Notes on Thoracic Anaesthesia

April 2011

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Richard W. D. Nickalls 2

Richard W. D. Nickalls

Department of Anaesthesia, Nottingham University Hospitals, City Hospital Campus, Nottingham, UK

[email protected] http://www.nickalls.org/

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revision 6 April 2011 3

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The author gratefully acknowledges generous ﬁnancial support from the Nottingham Anaesthetic Trust Fund (Depart- ment of Anaesthesia, City Hospital), the City Hospital Medical Staff Research Fund, Smiths Medical (http://www.smiths- medical.com), SonoSite (http://www.sonosite.com) and the Anthony Booth Trust (http://www.aplasticanaemia.co. uk), and Stewart’s (http://www.stewartscoffees.co.uk) to cover printing costs and enable this booklet to be made freely available to those on the Thoracic and Intensive Care training modules.

PORTEX — Smiths Medical, Hythe, Kent, UK

The single biggest problem we face is that of visualisation. Richard P. Feynman (1918–1988)1

1The Mathematical Gazette, (1996); 80, 267 5

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HIS introductory booklet is essentially a collection of practical notes on some of the topics relevant to the thoracic anaesthesia training module, and reﬂects a distinctly T personal approach. It is largely a vehicle for useful references, and still represents ‘work in progress’; for example, Chapter 1 is clearly rudimentary—waiting to be distilled further. The main topics are essentially those for which I developed some interest and tried to establish some underlying conceptual structure. Most chapters were motivated by a particular question or line of approach, as follows.

Anatomy — what is the useful functional anatomy for thoracic anaesthetists? Bronchoscopy — how does the ﬁbreoptic bronchoscope inﬂuence our perceived orientation of the anatomy? Tracheostomy — how can we avoid tracheostomy-related problems? One-lung anaesthesia — is there an optimum sequence for placing a double- lumen tube? Drugs — can particular dilutions facilitate administering vasoactive drugs? Supporting technologies — how did some of the key developments arise? I would like to thank Dr J James 2 for help with the virtual bronchoscopy part of Figure 5.1, and all those anaesthetists who contributed data to the TEPID database. Finally, I would also like to acknowledge the considerable help and assistance I have received from the Operating Department Practitioners, the Theatre Practitioners, and the staff at the PGMEC library and Department of Medical Illustration. RWD Nickalls April 2011

2Department of Radiology, Nottingham University Hospitals, City Hospital Campus, Nottingham, UK.

6 Contents

Preface6

1 General topics 12 1.1 Syllabus ...... 12 1.2 General resources ...... 12 1.3 Preoperative evaluation ...... 18 1.3.1 Lung function evaluation ...... 18 1.3.2 Cardiac function evaluation ...... 20 1.3.3 Obesity-related problems ...... 20 1.4 Open lung biopsy ...... 20 1.5 Tracheal resection ...... 21 1.6 Differential lung ventilation ...... 21 1.7 Thymectomy and myasthenia gravis ...... 21 1.8 Bilateral pleurectomy via sternal split ...... 22 1.9 Lung-volume reduction surgery ...... 22 1.10 Management of ﬂail-chest ...... 23 1.11 Pneumothorax ...... 23 1.11.1 Radiology ...... 23 1.11.2 Cavity expansion with N2O...... 23 1.11.3 Chest drains ...... 24 1.11.4 Chest-drain bottles ...... 24 1.11.5 Subcutaneous emphysema ...... 25 1.12 Empyema ...... 25 1.13 Sickle cell disease ...... 25 1.13.1 Anaesthesia ...... 25 1.13.2 The transfusion controversy ...... 27 1.13.3 Managing sickle-cell crisis ...... 27 1.13.4 Pathophysiology ...... 28 1.13.5 Haemoglobin molecular-chemistry ...... 28 1.13.6 HbS & O2 dissociation curve ...... 29

7 CONTENTS 8

2 Epidural block 30 2.1 Anatomy ...... 31 2.1.1 The epidural database (TEPID) ...... 32 2.2 General aspects ...... 33 2.2.1 Awake or under GA? ...... 33 2.2.2 Midline approach ...... 33 2.2.3 Paramedian approach ...... 33 2.2.4 Reducing catheter migration / fallout ...... 34 2.2.5 Radiographic placement ...... 34 2.2.6 Fibreoptic guided placement ...... 34 2.3 Drugs ...... 34 2.4 Complications ...... 36 2.4.1 Epidural catheter disconnection ...... 36 2.4.2 Abscess ...... 36 2.4.3 Haematoma & DVT prophylaxis ...... 37 2.5 Paravertebral block ...... 37

3 Tracheostomy & related airway problems 40 3.1 Introduction ...... 41 3.1.1 Local anaesthetic for fibreoptic bronchoscopy of the trachea . . . 41 3.2 Tracheostomy tubes ...... 41 3.2.1 Portex ...... 42 3.2.2 Tracoe ...... 42 3.2.3 Rusch¨ ...... 43 3.2.4 Moore tube ...... 43 3.3 Tracheostomy—when? ...... 43 3.4 Percutaneous tracheostomy ...... 43 3.5 Surgical tracheostomy ...... 45 3.5.1 Recommendations ...... 45 3.6 Changing a tracheostomy tube ...... 49 3.6.1 Preparation ...... 50 3.6.2 Changing the tube ...... 51 3.6.3 Check the position bronchoscopically ...... 52 3.7 Anaesthetising a patient with a laryngectomy ...... 52 3.8 Anaesthetising a patient with a tracheostomy in situ ...... 52 3.8.1 Postoperative management ...... 54 3.9 Montgomery T-tube placement ...... 54 3.10 Difficult airway & trans-tracheal needle ventilation ...... 54 3.11 Miscellaneous problems ...... 55 3.11.1 Obstruction ...... 56 3.11.2 Difficulty inserting the inner tube ...... 57 3.11.3 Air leak ...... 57 CONTENTS 9

3.11.4 Tracheostomy recently removed ...... 58

4 Lung anatomy 59 4.1 Anatomical terms ...... 59 4.2 History of lung anatomy ...... 61 4.2.1 Bronchopulmonary segment ...... 61 4.3 Lung development & embryology ...... 63 4.4 Nomenclature ...... 64 4.4.1 Right lung ...... 64 4.4.2 Left lung ...... 64 4.5 Carina ...... 65 4.5.1 Factors moving the carina ...... 65 4.6 Right-upper lobe oriﬁce ...... 66 4.7 Aberrant bronchus ...... 66 4.8 References ...... 74

5 Fibreoptic bronchoscopy 78 5.1 History ...... 79 5.2 Bronchoscopy simulator ...... 80 5.3 Carina ...... 80 5.4 Left subcarina & beyond ...... 81 5.5 Right subcarina & beyond ...... 83 5.6 Image orientation ...... 85 5.6.1 Axial rotation ...... 85 5.6.2 Bending ...... 86 5.6.3 Camera-mode ...... 86 5.7 Anaesthesia for bronchoscopy ...... 87 5.7.1 Short duration ...... 87 5.7.2 Long duration ...... 87 5.7.3 Local anaesthesia & sedation ...... 89 5.7.4 Venturi jet ventilation ...... 89 5.8 References ...... 89 5.8.1 Complications ...... 90 5.8.2 Fibreoptic intubation ...... 90

6 Tubes and bronchus blockers 92 6.1 The Univent tube, 1984 ...... 92 6.2 The Hunsaker jet ventilation tube ...... 93 6.3 Bronchus blockers ...... 93 6.4 Double-lumen tubes ...... 94 6.4.1 History ...... 94 6.4.2 The BronchoCath ...... 96 6.4.3 The tube database (TEPID) ...... 97 CONTENTS 10

7 One-lung anaesthesia 100 7.1 Right double-lumen tube ...... 100 7.2 Left double-lumen tube ...... 100 7.3 Placing double-lumen tubes ...... 101 7.3.1 Preparation ...... 102 7.3.2 Intubation ...... 103 7.3.3 Stethoscope check ...... 105 7.3.4 Bronchoscopy — left-sided tube ...... 106 7.3.5 Bronchoscopy — right-sided tube ...... 109 7.3.6 Final tidal volume and pressure check ...... 110 7.4 Turning the patient laterally ...... 110 7.5 One-lung anaesthesia ...... 111 7.5.1 Preparation ...... 112 7.5.2 One-lung ventilation ...... 112 7.5.3 Management of one-lung anaesthesia ...... 113 7.5.4 Returning to two-lungs ...... 115 7.6 Turning the patient supine ...... 115 7.7 Extubation ...... 116 7.8 Complications ...... 116 7.8.1 Intraoperative ...... 116 7.8.2 Postoperative ...... 117 7.9 General references ...... 119 7.9.1 Tracheostomy and one-lung ventilation ...... 122 7.9.2 One-lung anaesthesia ...... 123 7.9.3 Tracheal bronchus ...... 124 7.9.4 Physiology & pathology ...... 124 7.9.5 Flow/pressure/volume loops ...... 125

8 Drugs 126 8.1 Cardiovascular drugs ...... 126 8.1.1 Infusions: dilutions and use ...... 128 8.1.2 Bolus dosage ...... 129 8.1.3 Noradrenaline ...... 130 8.1.4 References ...... 131 8.2 Somatostatin analogues & carcinoid ...... 133 8.2.1 Octreotide ...... 133 8.2.2 Ketanserin ...... 133 8.2.3 Carcinoid tumours ...... 133 8.2.4 Anaesthesia for bronchial carcinoid resection ...... 133 8.2.5 References ...... 136 8.3 Haemostatic drugs ...... 138 8.4 Remifentanil ...... 138 CONTENTS 11

8.4.1 Bolus ...... 138 8.4.2 Infusion ...... 139 8.4.3 References ...... 139

9 Supporting technologies 141 9.1 Serendipity ...... 142 9.2 Tuohy needle with Huber point and Lee markings ...... 143 9.3 Pulse oximetry ...... 144 9.4 MAC ...... 146 9.4.1 History ...... 146 9.4.2 Age-corrected MAC ...... 151 9.4.3 Temperature corrected MAC ...... 157 9.4.4 Dosage and MAC correction ...... 157 9.4.5 References ...... 161 9.5 Arterial line ...... 166 9.5.1 History ...... 166 9.5.2 Anatomy ...... 167 9.5.3 Allen test ...... 168 9.5.4 Systolic pressure variation ...... 170 9.5.5 Complications ...... 170 9.6 Central venous catheter ...... 171 9.6.1 History ...... 171 9.6.2 References ...... 174 9.6.3 Optimum position ...... 176 9.6.4 Anatomy ...... 176 9.6.5 Position of CVP tip ...... 177 9.6.6 General ...... 178 9.6.7 Ultrasound guided ...... 179 9.6.8 External jugular vein ...... 180 9.6.9 Axillary vein ...... 180 9.6.10 Femoral vein ...... 181 9.6.11 Complications ...... 182 9.7 Pulmonary artery catheter ...... 183 9.7.1 History ...... 183 9.7.2 Decline in use ...... 186 9.8 Computers & information technology ...... 187 9.8.1 History of the anaesthesia record ...... 187 9.8.2 The anaesthesia workstation ...... 189 9.8.3 References ...... 191

Colophon 196

Index 1 General topics

1.1 Syllabus

HE thoracic anaesthesia syllabus for the CCT in Anaesthesia is detailed in the ‘cardiothoracic’ sections of the Intermediate, Higher and Advanced-level training T documents (2nd edition, August 2010) on the Royal College of Anaesthetists website as follows: Intermediate: http://www.rcoa.ac.uk/docs/CCTAnnex C.doc Higher: http://www.rcoa.ac.uk/docs/CCTAnnex D.doc Advanced: http://www.rcoa.ac.uk/docs/CCT in Anaesthetics Annex E.doc

1.2 General resources

Books • Lewis MI and McKenna RJ (2010). Medical management of the thoracic surgery patient, 560 pp. (Saunders) ISBN 978-1-4160-3993-8. For TOC 1 see: http://www. sciencedirect.com/science/book/9781416039938 • Searl CP and Ahmed ST (Eds.) (2010). Core topics in anesthesia. 230 pp. (Cam- bridge University Press) ISBN 978-0-521-86712-2

• Mashour GA (2010). Consciousness, awareness and anesthesia. 274 pp. (Cambridge University Press) ISBN 978-0-521-51822-2 • Lumb A (Ed.) (2010). Nunn’s applied respiratory physiology. 7th ed. (Elsevier). 568 pp. ISBN 978-0-7020-2996-3

1Table Of Contents

12 CHAPTER 1. GENERAL TOPICS RWD Nickalls 

• Hopkins R, Peden C and Ghandi S [Eds.] (2009). Radiology for anaesthesia and intensive care. 2nd ed., 328 pp. (Cambridge University Press) ISBN 978-0-521- 73563-6 • Kofke WA and Nadkarni VM [Eds.] (2007). New vistas in patient safety and simulation. Anesthesiology Clinics; 25 (June), 209–390 (Elsevier, Inc) [chapters: Anesthesiology national CME program and ASA activities in simulation / Does simulation improve patient safety?: self-efﬁcacy, competence, operational performance, and patient safety / Simulation applications for human factors and systems evaluation / Credentialing and certifying with simulation / Statewide simulation systems: the next step for anesthesiology? / Crew resource management and team training / Simulation: translation to improved team performance / Virtual worlds and team training / Virtual reality simulations / Procedural simulation / Debrieﬁng with good judgment: combining rigorous feedback with genuine inquiry / Integration of standardized patients into simulation ] • Slinger P [Ed.] (2008). Thoracic anesthesia. Anesthesiology Clinics; 26 (June), 241–398 (Elsevier, Inc) [chapters: Evidence-based management of one-lung ventilation / Oxygen toxicity during one-lung ventilation: is it time to re-evaluate our practice? / Anesthetic considerations for airway stenting in adult patients / Perioperative anesthetic management for esophagectomy / Anesthetic considerations for patients with anterior mediastinal masses / The emerging role of minimally invasive surgical techniques for the treatment of lung malignancy in the elderly / Prevention and management of perioperative arrhythmias in the thoracic surgical population / Pulmonary vasodilators—treating the right ventricle / Post thoracotomy pain management problems / Postthoraco- tomy paravertebral analgesia: will it replace epidural analgesia? / Advances in extracorporeal ventilation ] • Allman KG, Wilson IH (Eds.) (2006). Oxford Handbook of Anaesthesia. 2nd. ed. (Oxford University Press) [good sections on (a) THORACICANAESTHESIA (pp. 351– 383), and (b) DRUG FORMULARY (pp. 1105–1165).] • Pearce A and Gould G (2005). Thoracics. In: Allman KG, McIndoe AK and Wilson IH (Eds.) Emergencies in Anaesthesia, 1st. ed., pp. 193–220 (Oxford University Press). • Cobbold RSC (2006). Foundations of biomedical ultrasound. (Oxford University Press). 822 pp. • Chassot PG (2003). Cardiovascular and thoracic anaesthesia. [see book review: Br. J. Anaesth.; 91, 928] • Kaplan JA and Slinger PD [Eds.] (2003). Thoracic anesthesia. 3rd ed., (Churchill Livingstone, Philadelphia, USA). ISBN 0443066191 [excellent] CHAPTER 1. GENERAL TOPICS RWD Nickalls 

• Marshall BE, Longnecker DE and Fairley HB [Eds.] (1988). Anesthesia for thoracic procedures. (Blackwell Scientiﬁc Publications). 632 pp.

Articles • Burwell DR and Jones JG (1996). The airways and anaesthesia; I: anatomy, physiology and ﬂuid mechanics. Anaesthesia; 51, 849–857 (September issue). II: pathophysiology. Anaesthesia; 51, 943–955 (October issue). • Campos JH (2009). Update on selective lobar blockade during pulmonary resections. Current Opinion in Anaesthesiology; 22, 18–22. • Canet J, Gallart L, Gomar C et al. (2010). Prediction of postoperative pulmonary complications in a population-based surgical cohort. Anesthesiology; 113, 1338– 1350. • Levin AI, Coetzee JF and Coetzee A (2008). Arterial oxygenation and one-lung anesthesia. Current Opinion in Anaesthesiology; 21, 28–36 [107 refs] • Metzger RJ, Klein OD, Martin GR and Krasnow MA (2008). The branching program of mouse lung development. Nature; 453, 745–756 (5 June). [editorial: 733–735 (Warburton 2008)] • Ott HC, Clippinger B, Cobrad C, Schuetz C, Pomerantseva I, Ikonomou L, Kotton D and Vacanti JP (2010). Regeneration and orthotopic transplantation of a bioartiﬁcial lung. Nature Medicine; 16, 927–933. • Payen J-F (2010). Toward tailored sedation with halogenated anesthetics in the Intensive Care Unit? Anesthesiology; 113, 1268–9. [Editorial] • Pearce A (2004). Thoracic anaesthesia update. Update in Anaesthesia (June 2004); 18. http://update.anaesthesiologists.org/2004/ [or follow links to thoracic topics] • Ross AF and Ueda K (2010). Pulmonary hypertension in thoracic surgical patients. Current Opinion in Anaesthesiology; 23, 25–33. • Severinghaus JW (2009). Gadgeteering for health care: [The JW Severinghaus lecture on translational science] Anesthesiology; 110, 721–728. • Shafer SL (2007). Did our brains fall out? Anesthesia & Analgesia; 104, 247–248. • Shafer SL (2009). Critical thinking in anesthesia. Anesthesiology; 110, 729–737. • Slinger PD (2003). Acute lung injury after pulmonary resection: more pieces of the puzzle. Anesthesia and Analgesia; 97, 1555–1557. [49 refs] • Warburton D (2008). Order in the lung Nature; 453 (5 June), 733–735 [editorial to Metzger et al. (2008)]. CHAPTER 1. GENERAL TOPICS RWD Nickalls 

Book/journal searches Good starting points are (a) Google books (http://books.google.com/), and (b) the Wikipedia page on ‘book sources’ (http://en.wikipedia.org/wiki/book_sources/). For buying books (secondhand and new) Abebooks (http://www.abebooks.com/) is particularly useful, since it is usually possible to ﬁnd the website & telephone number of the individual booksellers, and then buy from them directly.

• PubMed Central (PMC): http://www.ncbi.nlm.nih.gov/pmc/. A free archive of life sciences journals. See the ‘journal list’ for list of all available journals.

• Science Direct: http://www.sciencedirect.com/ A particularly useful interface for viewing the tables of contents (TOC) of journals.

• Unbound Medicine: http://www.unboundmedicine.com/medline/ebm/ This is a useful free interface to the MEDLINE search engine.

• Priory Medical Journals Online: http://www.priory.com/

• The Cochrane Library: http://www.thecochranelibrary.com/ • Copac: http://copac.ac.uk/ It is the national, academic and specialist library catalogue. It provides free access to the merged online catalogues of 24 major research libraries in the UK and Ireland, including the British Library, and the national libraries of Scotland, Wales and Ireland.

• British Library (London): http://www.bl.uk/ The BL integrated catalogue is freely available online.

• Nottingham Univ. library catalogue: http://aleph.nottingham.ac.uk/ALEPH/ • Project Gutenberg: http://www.gutenberg.org/ Free eBooks on-line.

Anesthesiology Clinics for TOC 2 see: http://www.sciencedirect.com/science/journal/19322275

• Cardiac anesthesia: today and tomorrow (2008); 26 (September) • Thoracic anesthesia (2008); 26 (June) • New vistas in patient safety and simulation (2007); 25 (June)

2Table Of Contents CHAPTER 1. GENERAL TOPICS RWD Nickalls 

Thoracic Surgery Clinics for TOC see: http://www.sciencedirect.com/science/journal/15474127

• Thymoma (2011); 21 (February) • Chest wall surgery (2010); 20 (November) • Air leak after pulmonary resection (2010); 20 (August) • Technical advances in mediastinal surgery (2010); 20 (May) • Imaging of thoracic diseases (2010); 20 (February) • Surgical conditions of the diaphragm (2009); 19 (November) • Thoracic surgery in the elderly (2009); 19 (August) • Update on surgical and endoscopic management of emphysema (2009); 19 (May) • Diseases of the mediastinum (2009); 19 (February) • Thoracic anatomy: Chest wall, airway, lungs. (2007); 17 (November)

Clinics in Chest Medicine for TOC see: http://www.sciencedirect.com/science/journal/02725231

• Interventional pulmonology (bronchoscopy) (2010); 31 (March) • Tuberculosis (2009); 30 (December) • Obesity and respiratory disease (2009); 30 (September) • Fungal diseases (2009); 30 (June) • Nonpulmonary critical care (2009); 30 (March) • Update in sepsis (2008); 29 (December) • Controversies in mechanical ventilation (2008); 29 (June) • Contemporary chest imaging (2008); 29 (March) • Artiﬁcial airways (2003); 24 (September). • Pulmonary function testing (2001); 22 (December). • Prolonged critical illness: management of long-term acute care (2001); 22 (March). • Flexible bronchoscopy update (2001); 22 (June). CHAPTER 1. GENERAL TOPICS RWD Nickalls 

• Acute respiratory distress syndrome (2000); 21 (September). • Intensive care unit complications (1999); 20 (June). • Flexible bronchoscopy in the 21st century (1999); 20 (March).

History • Comroe JH (1977). Retrospectroscope: insights into medical discovery. (Von Gehr Press, Menlo Park, California, USA). ISBN 0-9601470-1-2 [a collection of essays which originally appeared in American Review of Respiratory Disease during the period 1975–1977.] • Swazey JP and Reeds K (1978). Today’s medicine, tomorrow’s science: essays on paths of discovery in the biomedical sciences. (U.S. Department of Health, Education and Welfare, Public Health Service, National Institutes of Health, USA; DHEW Publication No. (NIH) 78-244). [available for download from http:// newman.baruch.cuny.edu/digital/2001/swazey_reeds_1978/] • Watson JD (1968). The Double Helix: a personal account of the discovery of the structure of DNA, (Weidenfeldt & Nicholson); (Penguin Books 1970); (WW Norton & Co., 1980; Ed. Gunter S. Stent3). • Maltby RJ (Ed.) (2002). Notable names in anaesthesia. (Royal Society of Medicine Press, London). ISBN 1853-155-128. 254 pp. • Sykes K and Bunker J (2007). Anaesthesia and the practice of medicine: historical perspectives. (224 pp.) ISBN 1-85315-674-4 • Medical History is the journal of the Wellcome Historical Medical Library, London. A useful resource of historical articles—some of which relate to anaesthesia. It is available on-line via PubMed Central at http://www.ncbi.nlm.nih.gov/pmc/ journals/228/. • The Wellcome Collection. http://www.wellcomecollection.org/ • The Wellcome Library. http://library.wellcome.ac.uk/ For a list of free online titles project see http://library.wellcome.ac.uk/backfiles/.

Miscellaneous • Slinger’s thoracic anaesthesia site: http://www.thoracic-anesthesia.com/ • Chest (see archive, collections and supplements): http://chestjournal.chestpubs. org/

3This excellent edition also includes a commentary, reviews, and copies of the original 1953 papers. CHAPTER 1. GENERAL TOPICS RWD Nickalls 

• Medscape’s clinical reference website: http://emedicine.medscape.com/ There is an extensive database on clinical procedures. See also the sections on thoracic surgery, radiology, critical− care, etc. − − • Best evidence topics: http://www.bestbets.org. A collection of mini-reviews presenting the evidence base for various topics.

• Virtual Hospital: http://www.uihealthcare.com/vh/ Many interesting thoracic articles available via their ‘search’ facility.

• Bronchoscopy Atlas: http://www.int-med.uiowa.edu/research/tlirp/ BronchoscopyAtlas/Home.html • Clinical Cases and Images website: http://clinicalcases.org/. • Learning Radiology website: http://www.learningradiology.com/ • Wikipedia is well worth a trawl occasionally, since it has an increasing number of surprisingly detailed medical entries with excellent links; for example: http://en.wikipedia.org/wiki/Tracheal_intubation http://en.wikipedia.org/wiki/History_of_tracheal_intubation http://en.wikipedia.org/wiki/History_of_anatomy http://en.wikipedia.org/wiki/History_of_general_anaesthesia

• Anesthesia Patient Safety Foundation (APSF): (http://www.apsf.org/).

• SHEPHERDS FALKINERS, 76 Southampton Row, London, WC1B 4AR. Tel: 020- 783-11151 http://store.falkiners.com/ (ﬁne paper & bookbinding supplies)

1.3 Preoperative evaluation

1.3.1 Lung function evaluation The British Thoracic Society guidelines article (BTS/SCTS Working Group 2001) recommends an FEV1 > 2 litres for pneumonectomy, and FEV1 > 1 5 litres for a lobectomy. Patients with values less than these are ‘high risk’ and should be evaluated· further (transfer factor; exercise test). However, some patients with diffuse interstitial lung disease may well have a low transfer factor in spite of good spirometry, and should be evaluated further. This document gives details of preoperative respiratory and cardiovascular function tests for all such patients, and is well worth reading. Good general reviews are Datta and Lahiri (2003), Powell and Caplan (2001), Portch and McCormick (2009). Role of supine LFTs? Finally, we should not overlook the possibility that some supine lung-function testing (and cardiac testing) might be more appropriate for supine patients under anaesthesia—but I have failed to ﬁnd any literature on this as yet. CHAPTER 1. GENERAL TOPICS RWD Nickalls 

• Brunelli A (Ed.) (2008). Preoperative evaluation of lung resection candidates. Thoracic Surgery Clinics; 18, No. 1. • BTS/SCTS Working Group (2001). Guidelines on the selection of patients with lung cancer for surgery. Thorax; 56, 89–108. [182 refs] [can be downloaded from: http://thorax.bmj.com] • Datta D and Lahiri B (2003). Preoperative evaluation of patients undergoing lung resection surgery. Chest; 123, 2096–2013 [review article] • Gould G and Pearce A (2006). Assessment of suitability for lung resection. Continu- ing Education in Anaesthesia, Critical Care & Pain; 6 (No 3), 97–100. [BJA related journal] [good overview] • Kearney DJ et al. (1994). Assessment of operative risk in patients undergoing lung resection: impact of predicted pulmonary function. Chest; 105, 753–759. • Kinnear WJM (1997). Lung function tests: a guide to their interpretation. (Notting- ham University Press, Nottingham, UK). ISBN 1-897676-80-8. • Mark JBD (Ed) (1999). Perioperative cardiopulmonary evaluation and management. Chest; 115 Supplement (May). http://chestjournal.chestpubs.org/ • Melendez JA and Fischer ME (1997). Preoperative pulmonary evaluation of the thoracic surgical patient. In: Wilson RS [Ed.] Anaesthesia; Chest Surgery Clinics of North America; 7, 641–654. (Philadelphia, PA: WB Saunders, USA). • Portch D and McCormick B (2009). Pulmonary function tests and assessment for lung resection. Update in Anaesthesia (June 2009), p. 13–21. http://update. anaesthesiologists.org/2009/ [good overview] • Powell CA and Caplan CE (2001). Pulmonary function tests in preoperative pulmonary evaluation [92 refs]. In: Chupp GL (Ed), Clinics in Chest Medicine; 22 (no. 4, December) [this vol of Clinics in Chest Medicine also includes useful articles by Pride NB (Tests of forced expiration and inspiration), and Gibson CJ (Lung volumes and elasticity)] • Rennotte MT, Bacle P, Aubert G and Rodenstein DO (1995). Nasal continuous positive airway pressure in the perioperative management of patients with obstructive sleep-apnoea submitted to surgery. Chest; 107, 367–374. • Rielly JJ (1999). Evidence-based pre-operative evaluation of candidates for thoracotomy. Chest; 116 (Suppl 6), 474S–476S. • Smetana GW (1999). Pre-operative pulmonary evaluation. N. Engl. J. Med.; 340, 937–944. [see also the follow-up letters stressing signiﬁcance of detecting preoperative sleep apnoea: Marx JJ et al. (1999), 341, 613–614] CHAPTER 1. GENERAL TOPICS RWD Nickalls 

1.3.2 Cardiac function evaluation • Eagle KA et al. (2002). ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery—executive summary. Anesth. Analg.; 94, 1052– 1064. [see editorial P 1378-9] • Fleisher LA (1998). Pre-operative cardiac evaluation before non-cardiac surgery. In: Bailliere’s` Clinical Anaesthesiology; Chapter 4, 373–390. (Bailliere` Tindall, London). • Mark JBD (Ed) (1999). Perioperative cardiopulmonary evaluation and management. Chest; 115 Supplement (May). http://chestjournal.chestpubs.org/

1.3.3 Obesity-related problems This list is included here since one-lung anaesthesia in obese patients is such a formidable technical exercise. It is sometimes worth considering the use of temporary post-extubation CPAP or BIPAP support in recovery. • Obesity and respiratory disease. Clinics in Chest Medicine (2009); 30 (September) • Adams JB and Murphy PG (2000). Obesity in anaesthesia and intensive care. Br. J. Anaesth.; 85, 91–108 [164 refs].

• Marik P and Varon J (1998). The obese patient in the ICU. Chest; 113, 492–498. • Shenkman Z, Shir Y and Brodsky JB (1993). Perioperative management of the obese patient. Br. J. Anaesth.; 70, 349–359. [excellent: 120 refs] • von Ungern-Sternberg BS, Regli A, Schneider MC, Kunz F and Reber A (2004). Effect of obesity and site of surgery on perioperative lung volumes. Br. J. Anaesth.; 92, 2002–2207.

1.4 Open lung biopsy

These patients usually have diffuse lung disease and relatively poor lung function, and are generally referred to the surgeons following a failed percutaneous or bronchoscopic lung biopsy. Although a single-lumen tube is often all that is required for a supine procedure (e.g., a mediastinotomy or mediastinoscopy), a double-lumen tube and lateral position is sometimes necessary. Consider selective lobar isolation if lung function is poor (see Mentzelopoulos, Rellos, Tzouﬁ et al. 2003).

• Mentzelopoulos SD, Rellos K, Tzouﬁ MJ et al. (2003). A double-lumen tube technique for selective lobar isolation. European Journal of Anaesthesiology; 20, 984–992. CHAPTER 1. GENERAL TOPICS RWD Nickalls 

1.5 Tracheal resection

• Cokis C and Strang T (2000). Airway management for carinal tumour resection. Anaesthesia and Intensive Care; 28, 570–572.

1.6 Differential lung ventilation

This is occasionally indicated in patients where the two lungs have a signiﬁcantly different compliance. The Drager¨ ventilators have the facility to be linked in pairs such that one functions as the slave of the other, allowing the phase relations of the two ventilators to be easily controlled.

• Hedenstierna G (1985). Differential ventilation in bilateral lung disease. Europ. J. Anaesthesiol.; 2, 1. • Hedenstierna G et al. (1984). Ventilation and perfusion of each lung during differential ventilation with selective PEEP. Anesthesiology; 61, 369.

1.7 Thymectomy and myasthenia gravis

Good articles on the anaesthetic management of myasthenia gravis are few in number; the most useful ones I have found are those by Zielinski (2011), Eisenkraft (1987) and Redfern et al. (1987). Note that the February 2011 issue of the Thoracic Surgery Clinics is on thymoma. A patient with myasthenia gravis is typically maintained on oral pyridostigmine tablets. Postoperatively either pyridostigmine (subcutaneously) or neostigmine 4 is generally used until the patient’s usual oral maintenance dose (pyridostigmine tablets) can be resumed. Note that 60 mg of the oral pyridostigmine preparation is equivalent to 2 mg of the parenteral product.5 A typical adult total daily parenteral dose of pyridostigmine is approximately 10–40 mg (1–4 mg given 3–4 hrly). The exact neuromuscular defect (presynaptic vs. postsynaptic) seems not to be fully resolved as yet. The presynaptic acetylcholine stores and their release are not diminished in myasthenia (Cull-Candy et al. 1980).

• Zielinski M (2011). Management of myasthenic patients with thymoma. Thoracic Surgery Clinics; 21 (February), 47–57. • Cull-Candy SG et al. (1980). On the release of transmitter at normal, myasthenia gravis, and myasthenic syndrome affected human end-plates. Journal of Physiology (Lond.); 299. 621–638 [from Sosis (1985)]

4Pyridostigmine is the preferred agent owing to its longer action. 5CHN Pharmacy factsheet. CHAPTER 1. GENERAL TOPICS RWD Nickalls 

• Eisenkraft JB (1987). Myasthenia gravis and thymic surgery: anaesthetic considerations. In: Gothard JWW [Ed.], Thoracic anaesthesia. Clinical Anaesthesiology; 1 (March); Chapter 8, 133–162. [excellent] • Redfern N et al. (1987). Thymectomy. Ann. Roy. Coll. Surg. Eng.; 68, 289–292.

1.8 Bilateral pleurectomy via sternal split

An important aspect of this procedure is taking care to avoid having both lungs partially deflated at the same time! This can easily happen once both pleura are open, and the resulting desaturation can be both severe and slow to recover. The problem tends to occur when the surgeons have almost finished working on the first lung, as then one of the surgeons may start investigating (& collapsing) the other lung before the first lung has been fully re-expanded. Note there is sometimes quite a long time-lag after re-expanding a lung and the saturation improving. The fact that the patient is supine compounds the problem, as there is no ‘bottom’ lung receiving most of the cardiac output. This is an important difference, since with a normal thoracotomy in the lateral position not only is the bottom lung always fully expanded but it is also receiving the majority of the cardiac output. The key principles are therefore (a) use a double-lumen tube, (b) use some PEEP, and (c) make sure the first lung is fully re-expanded before allowing the surgeons to start working on the other lung. The same general principles probably also apply for lung- volume reduction surgery, as this is usually a bilateral procedure via a sternal split as well (see below).

1.9 Lung-volume reduction surgery

• Calverley PMA (2003). Closing the NETT on lung volume reduction surgery. Thorax; 58, 651–653. [review of the National Emphysema Treatment Trial (NETT)] • Conacher ID (1997). Anaesthesia for the surgery of emphysema. Br. J. Anaesth.; 79, 530–538. • Cooper JD and Lefrak SS (1999). Lung-reduction surgery: 5 years on. The Lancet; 353 (Suppl. 1[surgery]), 26–27. [At 2 years pulmonary function had improved in the surgical group, but had worsened in the control (no-surgery group). By 3 5–4 yrs mortality during follow up was 30% (surgery) and 52% (no-surgery)] · • Szekely LA et al. (1997). Pre-operative predictors of operative morbidity and mortality in COPD patients undergoing bilateral lung-volume reduction surgery. Chest; 111, 550–558. CHAPTER 1. GENERAL TOPICS RWD Nickalls 

1.10 Management of ﬂail-chest

• Ahmed Z and Mohyuddin Z (1995). Management of flail chest injury: internal fixation versus endotracheal intubation and ventilation. The Journal of Thoracic and Cardiovascular Surgery; 110, 1676–1680. [Internal fixation (IF) is better; with IF mean period of IPPV was 3 9 days versus 15 days with IPPV only]. ·

1.11 Pneumothorax

• http://emedicine.medscape.com/thoracic_surgery/ >pneumothorax • Baumann MH and Strange C (1997). Treatment of spontaneous pneumothorax: a more aggressive approach? Chest; 112, 789–804 [132 refs] • Beauchamp G (1995). Spontaneous pneumothorax and pneumomediastinum. In: Pearson FG, [Ed.] Thoracic surgery. (Churchill Livingstone, New York, USA). pp. 1038–1040.

• Henry M, Arnold T and Harvey J (2003). BTS guidelines for the management of spontaneous pneumothorax. Thorax; 58 (Suppl 2), 39–52.

1.11.1 Radiology • O’Connor AR and Morgan WE (2005). Radiological review of pneumothorax. British Medical Journal; 330, 1493–1497.

1.11.2 Cavity expansion with N2O • Eger EI (1974). Nitrous oxide transfer to closed gas spaces. In: Eger EI Anaesthetic uptake and action (Williams & Wilkins Company, Baltimore, USA), Chapter 10, pp. 171–183. [lung cavity expansion is fast: volume doubles with 50% N2O; vol increases 4-fold with 75% N2O. Bowel expansion is much slower and less complete; with 75% N2O bowel gas volume increased 1 8-fold in 2 hrs, 2 5-fold in 4 hrs.] · · • Eger EI and Saidman LJ (1965). Hazards of nitrous oxide in bowel obstruction and pneumothorax. Anesthesiology; 26, 61–66. • Gold MI and Joseph SI (1973). Bilateral tension pneumothorax following induction of anaesthesia in two patients with chronic obstructive airway disease. Anesthesiol- ogy; 38, 93–97. CHAPTER 1. GENERAL TOPICS RWD Nickalls 

1.11.3 Chest drains Chest drains are potentially dangerous, and in May 2008 the National Patient Safety Agency (NPSA) issued an alert following 12 deaths and 15 serious adverse incidents—see the paper by Akram and Hartung (2009). The sizes of chest drains generally used in thoracic surgery are as follows: ward insertion 28 Fr; theatre insertion 36 Fr. Pneumonectomy: 1 drain; Lobectomy: 2 chest drains:- (anterior/apical/air) - (back/basal/blood). Chest drains are sometimes put on suction postoperatively in order to facilitate lung re- expansion (spontaneously breathing patients only). However, in the presence of a lung leak suction can be the cause of a tension pneumothorax if the total drain air flow is significant (i.e., if the suction cannot handle the total flow). Consequently, if you suspect a tension pneumothorax always disconnect the suction 6 from the under-water seal until the problem has been resolved. Never apply suction to a ventilated patient. There is also a nice ‘You tube’ internet video on “securing a chest drain” (search google for this). • Akram AR and Hartung TK (2009). Intercostal chest drains: a wake-up call from the National Patient Safety Agency rapid response report. J. R. Coll. Physicians Edinb.; 39, 117–120. [a nice review of chest drain-related complications] • Cerfolio RJ, Minnich DJ and Bryant DJ (2009). The removal of chest tubes despite an air leak or a pneumothorax. The Annals of Thoracic Surgery; 87, 1690–1694 (discussion: 1694-1696). • Harriss DR and Graham TR (1991). Management of intercostal drains (a review). British Journal of Hospital Medicine; 45, 383–386. • Harriss DR and Graham TR (1990). Management of intercostal drains British Medical Journal; 301, 1165. • Hyde J, Sykes T and Graham T (1997). Reducing morbidity from chest drains [editorial]. British Medical Journal; 314, 914–915. • Laws D, Neville E and Duffy J (2003). BTS guidelines for the insertion of a chest drain. Thorax; 58, 53–59.

1.11.4 Chest-drain bottles • Hunter J (2008). Chest drain removal. Nursing Standard; 22(45), 35–38. • Kam AC, O’Brien M and Kam PCA (1993) Pleural drainage systems. Anaesthesia; 48, 154–161. [excellent]

6If there is a tension pneumothorax, then disconnecting the suction will result in an immediate discharge of air through the under-water seal. CHAPTER 1. GENERAL TOPICS RWD Nickalls 

• Thompson R, Parker E, Sivaprakasam J and Hong V (2007). Observational study of the practice of chest drain removal in postoperative cardiac surgical patients. Anaesthesia; 62, 207–208. • Woodrow P (2005). Caring for patients with intrapleural chest drains. [East Kent Hospitals guidelines] Available on the internet [google key words: clinical guidelines Interpleural chestdrain guidelines (4)]

1.11.5 Subcutaneous emphysema • Beck PL, Heitman SJ and Mody CH (2002). Simple construction of a subcutaneous catheter for treatment of severe subcutaneous emphysema. Chest; 121, 647–649. • Cesario A, Margaritora S, Porziella V and Granone P (2003). Microdrainage via open technique in severe subcutaneous emphysema. Chest; 123, 2162–2163 [letter] • Herlan DB, Landreneau RJ and Ferson PF (1992). Massive spontaneous subcutaneous emphysema: acute management with infraclavicular “blow holes”. Chest; 102, 503–505. • Leo F, Solli P, Veronesi G et al. (2002). Efﬁcacy of microdrainage in severe subcutaneous emphysema. Chest; 122, 1498–1499.

1.12 Empyema

• DTB (2006). Managing empyema in adults. Drug and Therapeutics Bulletin; 44 (March), 17–21. http://www.dtb.org.uk/

1.13 Sickle cell disease

One-lung anaesthesia in patients with a sickle-cell condition is a formidable problem requiring preparation and coordination with the Haematology department. Unfortunately good references which are useful for thoracic anaesthetists are few in number.7 The NHS sickle cell and thalassaemia screening programme website (http://sct.screening. nhs.uk) is a useful source of information.

1.13.1 Anaesthesia The main principles are: (a) optimise Hb—aim for [HbA] greater than 70%—and treat anaemia, (b) chest physiotherapy and breathing exercises, (c) good hydration, (d) pre- oxygenation, (e) minimise factors which ‘right-shift’ the Hb dissociation curve,8 (f) use at

7See those I have indicated with a triangle . 8 4 i.e., correct acidosis, and avoid letting ETCO2 or temperature rise above normal. CHAPTER 1. GENERAL TOPICS RWD Nickalls 

9 least 50% FIO2 , (g) keep the patient warm, (h) no tourniquets (tourniquet deaths have been reported even with sickle-cell trait), (i) consider regional blocks to facilitate vasodilation, (j) avoid pre- and postoperative sedation. The most useful references I have come across from a purely practical point of view are marked by a triangle . 4 • Bannerjee AK, Layton DM, Rennie JA et al. (1991). Safe surgery in sickle-cell disease. Br J Surg; 78, 516–517. • Davies SC, Cronin E, Gill M, Greengross P, Hickman M and Normand C (2000). Screening for sickle cell disease and thalassaemia: a systematic review with sup- plementary research. Health Technology Assessment; 4 (No. 3). http://sct. screening.nhs.uk/ [see chapter 8: Prevalence of sickle cell and β-thalassaemia in England. (pp. 27–32)]. • Derkay CS, Bray G, Milmoe GJ et al. (1991). Adeno-tonsillectomy in children with sickle-cell disease. South Med J; 84, 205–208. • Esseltine DW, Baxter M, Bevan JC (1988). Sickle cell states and the anesthesiologist. Can. J. Anaesth; 35, 385–403. • Firth PG (2005). Anaesthesia for peculiar cells—a century of sickle cell disease. Br.4 J. Anaesth.; 95, 287–299. [excellent review; 96 refs] • Firth PG and Head CA (2004). Sickle cell disease and anesthesia. Anesthesiology; 4101, 766–785. [excellent review; 180 refs] • Gibson JR (1987). Anesthesia for the sickle-cell diseases and other hemoglobin- 4opathies. Seminars in Anesthesia; 6, 27–35. • Henderson K (1994). Sickle-cell disease and anaesthesia. Update in Anaesthesia; No. 4, 9–12. http://update.anaesthesiologists.org/1994/ • Homi J, Reynolds J, Skinner A et al. (1979). General anaesthesia and sickle-cell disease. BMJ; i, 1599–1601. • Howells TH, Huntsman RG, Boys JE and Mahmood A (1972). Anaesthesia and 4sickle-cell haemoglobin. Br. J. Anaesth.; 44, 975–987. • Marchant WA and Wright S (2001). Aortic cross-clamping in sickle cell disease. Anaesthesia; 56, 286–287. [letter] [exchanged transfused to Hb 10, HbA 61%, good hydration, warm, mild alkalosis: bypass cross-clamp 9 min; no problems] • McClain BC, Redd SA and Turner EA (1999). Sickle cell disease: a ’90s perspective4 on an old disease. In: Lake CL, Rice LJ and Sperry RJ (Eds) Advances in Anaesthesia; 16, 129–161 [97 refs].

9To facilitate vasodilation. CHAPTER 1. GENERAL TOPICS RWD Nickalls 

• Neumayr L, Koshy M and Haberkern C et al. (1998). Surgery in patients with 4Haemoglobin SC Disease. American Journal of Hematology; 57, 101–118. [cited from Marchant WA and Wright S, 2001] • Koshy M, Weiner SJ et al. (1995). The co-operative study of sickle-cell disease. Surgery and anaesthesia in sickle-cell disease. Blood; 86, 3676–3684. • Raff JP, Dobson CE and Tsai HM (2002). Transfusion of polymerised haemoglobin in a patient with severe sickle-cell anaemia. Lancet; 360, 464–465. • Vipond AJ and Caldicott LD (1998). Major vascular surgery in a patient with sickle cell disease. Anaesthesia; 53, 1204–1206.

1.13.2 The transfusion controversy These articles discuss two pre-operative treatments: (a) aggressive transfusion aimed at decreasing [HbS] to less than 30%, and (b) a more conservative approach designed simply to increase [Hb] to greater than 10 gm/100mls. While both regimens were equally effective in preventing post-operative complications, the ‘conservative’ regimen was associated with half as many transfusion reactions.

• Buchanan GR and Rogers ZR (1995). Preoperative transfusion in sickle-cell disease. N Eng J Med; 333, 1641. [letter] [reply to Vichinsky et al. 1995] • Haberkern CM, Neumayr LD, Orringer EP et al. (1997). Cholecystectomy in sickle- cell anemia patients: peri-operative outcome in 364 cases from the national preoperative transfusion study. Blood; 89, 1533–1542. • Vichinsky EP, Haberkern CM, Neumayr L et al. (1995). A comparison of conservative and aggressive transfusion regimes in the peri-operative management of sickle-cell disease. N Eng J Med; 333, 206.

1.13.3 Managing sickle-cell crisis • Ballas SK (1998). Sickle cell disease: clinical management. In: Bailliere’s Clinical Haematology, 11, (No. 1, March issue), 185–214. • Davies SC and Oni L (1997). Management of patients with sickle-cell disease. Br. Med. J.; 315, 656–60. • Konotey-Ahulu FID (1998). Opiates for sickle-cell crisis? Lancet; 351, 1438. • Serjeant GR (1997). Sickle-cell disease. Lancet; 350, 725–30. • Steinberg MH (1999). Management of sickle cell disease. New Engl. J. Med.; 340, 1021–1030. CHAPTER 1. GENERAL TOPICS RWD Nickalls 

• Vichinsky E (2002). New therapies in sickle cell disease. Lancet; 360, 629–631. [L-arginine augments nitric oxide production anti-sickling and vaso-dilation] → • Vijay V, Cavenagh JD and Yate P (1998). The anaesthetist’s role in acute sickle-cell crisis. Br. J. Anaesth.; 80, 820–828.

1.13.4 Pathophysiology • Mozzarelli A, Hofrichter J, and Eaton WA (1987). Delay-time of hemoglobin-S polymerization prevents most cells from sickling in vivo. Science; 237, 500–506. • Serjeant GR and Serjeant BE (2001). Sickle cell disease. (Oxford University Press, Oxford, UK) • Steinberg MH (1998). Pathophysiology of sickle cell disease. In: Bailliere’s Clinical Haematology, 11, (No. 1, March issue), 163–184.

1.13.5 Haemoglobin molecular-chemistry The famous chemist Linus Pauling was instrumental in the discovery that sickle-cell disease was due to a haemoglobin abnormality. Max Perutz and John Kendrew received the Nobel Prize in 1962 for determining the structure of haemoglobin. • Cooper C and Wilson M (1997). Cold feet. New Scientist; The Last Word, (Febru- ary 1st). [a fascinating note on the mechanism by which the amount of heat (∆H) associated with the exothermic oxygen-binding to haemoglobin —and its reverse— allows the feet of antarctic penguins to remain non-frozen. Its role in other animals is also explored.] • Itano HA and Pauling L (1949). A rapid diagnostic test for sickle cell anemia. Blood; 4, 66. • Pauling L and Itano HA, Singer SJ and Wells IC (1949). Sickle cell anaemia, a molecular disease. Science; 110, 543–548. • Perutz MF (2003). The second secret of life. In: I wish I’d made you angry earlier. (Cold Spring Harbor Laboratory Press; ISBN 0–87969–674–5). pp. 315–337. • Perutz MF (1997). Science is not a quiet life: unravelling the atomic mechanism of haemoglobin. (World Scientiﬁc Publishing Co. Pte. Ltd.; London/Singapore) 636 pp. ISBN 9810230575 (pbk.) [annotated collection of key papers by Perutz relating to the structure of haemoglobin; includes a section on ‘molecular pathology of human haemoglobin’.] • Perutz MF (1990). Mechanism of cooperativity and allosteric regulation in proteins. (Cambridge University Press; ISBN 0–521–38648–9). 101 pp. CHAPTER 1. GENERAL TOPICS RWD Nickalls 

• Swazey JP and Reeds K (1978). Today’s medicine, tomorrow’s science: essays on paths of discovery in the biomedical sciences. (U.S. Department of Health, Education and Welfare, Public Health Service, National Institutes of Health, USA; DHEW Publication No. (NIH) 78-244). See: Chapter 5: The lesson of rare maladies: sickled cells, molecular disease, and the genetic control of protein structure, pp. 73– 92. [available for download from http://newman.baruch.cuny.edu/digital/ 2001/swazey_reeds_1978/] [excellent historical overview of the science relating to sickle cell disease]

1.13.6 HbS & O2 dissociation curve • Becklake MR et al. (1955). Oxygen dissociation curves in sickle-cell anemia, and in subjects with the sickle-cell trait. J. Clin. Invest.; 34, 751–755. • Gill SJ et al. (1979). Oxygen binding to sickle-cell hemoglobin. J Mol Biol; 130, 175–189. [cited from Hsia, 1998]

• Hsia CCW (1998). Respiratory function of hemoglobin. N Engl J Med; 338, 239–247. • Ueda Y, Nagel RL and Bookchin RM (1979). An increased Bohr effect in sickle-cell anemia. Blood; 53, 472–480. [from Hsia, 1998] 2 Epidural block

IRTUALLY all thoracic patients at the City Hospital have an epidural block unless this is contraindicated for some reason. Note the recent epidural ‘best practice’ Vpublication (RCoA 2010). For history of the development of the epidural needle see Section 9.2.

• RCoA (2010). Best practice in the management of epidural analgesia in the hospital setting. Faculty of Pain Medicine, Royal College of Anaesthetists, UK (November 2010)

• Ballantyne JC (2004). Does epidural analgesia improve surgical outcome? Br. J. Anaesth.; 92, 4–6. [answer: ‘yes, but . . . ’] • Desborough JP (1996). Thoracic epidural analgesia in cardiac surgery. Anaesthesia; 51, 805–807. [editorial] • Gould TH, Grace K, Thorne G and Thomas M (2002). Effect of thoracic epidural anaesthesia on colonic blood ﬂow. Br. J. Anaesth.; 89, 446–451. • Howell CJ, Dean T, Lucking L, Dziedzic K, Jones PW and Johanson RB (2002). Randomised study of long term outcome of epidural versus non-epidural analgesia during labour. Br. Med. J., 325, 357–359. [no difference in incidence of back-pain] • Rigg JR, Jamrozik K, Myles PS et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. Lancet, 359, 1276–1282. [correspondence: Lancet, 360, 568–569.] • Sielenkamper¨ AW and van Aken H (2003). Thoracic epidural anesthesia: more than just anesthesia/analgesia? Anesthesiology; 99, 523–525. [neurophysiological effects & experiments in rats]

30 CHAPTER 2. EPIDURAL BLOCK RWD Nickalls 

• Teoh DA, Santosham KL, Lydell CC, Smith DF and Beriault MT (2009). Surface anatomy as a guide to vertebral level for thoracic epidural placement. Anesthesia and Analgesia; 108, 1705–1707. • Wheatley RG, Schug SA and Watson D (2001). Safety and efﬁcacy of postoperative epidural analgesia. Br. J. Anaesth., 87, 47–61.

2.1 Anatomy

Two excellent books on intercostal and epidural anatomy for anaesthetists are those by Mackintosh and Bryce-Smith (1953) and Mackintosh and Lee (1973). A convenient way of identifying the thoracic levels is to use the surface markings of the scapula; T2 = top border of scapula (superior angle); T5 = middle of scapula; T8 = bottom of scapula (inferior angle). Since a typical thoracotomy incision follows the 5th rib, the aim is to locate the tip of the catheter at about T5 (middle of scapula). Inserting the Tuohy needle at the level T7–T8 (bottom of the scapula one space) generally works well. For a thoraco-abdominal± incision and also for an Ivor-Lewis operation, the tip of the epidural catheter needs to be at about T7 (middle of the range T4–T10). Consequently, inserting the Tuohy needle two–three spaces further down from the bottom of the scapula ( one space) is generally satisfactory. ± • Carnie J, Boden J and Gao Smith F (2002). Prediction by computerised tomography of distance from skin to epidural space during thoracic epidural insertion. Anaesthesia; 57, 701–704. [midline, T6–T9] • Harrison GR and Clowes NWB (1985). The depth of the lumbar epidural space from the skin. Anaesthesia; 40, 685–687. • Hoffmann VLH, Vercauteren P, Buczkowski PW and Vanspringel GLJ (1997). A new combined spinal-epidural apparatus: measurement of the distance to the epidural and subarachnoid spaces. Anaesthesia; 52, 350–355. • Hogan QH (1998). Epidural anatomy: new observations. Can. J. Anaesth.; 45 (Suppl.), R40–R44. [part of the refresher course outline] • Kao MC, Tsai SK, Chang WK, Liu HT, Hsieh YC, Hu JS and Mok MS (2004). Pre- diction of the distance from skin to epidural space for low-thoracic epidural catheter insertion by computed tomography. Br. J. Anaesth., 92, 271–273. [paramedian approach only] • Mackintosh RR and Bryce-Smith (1953). Local analgesia: abdominal surgery. (E & S Livingstone). • Mackintosh RR and Lee JA (1973). Lumbar puncture and spinal analgesia, 3rd ed. (Churchill Livingstone). ISBN 0-443-00997-X CHAPTER 2. EPIDURAL BLOCK RWD Nickalls 

2.1.1 The epidural database (TEPID) 1 Several studies have tried to correlate the depth of the epidural space from the skin with a single parameter (e.g., height, weight or BMI), but none has proved particularly useful (see references in Section 2.1). This suggests that using only a single parameter is probably the wrong approach. Consequently my TEPID database uses three parameters (height, weight and gender) and gives quite accurate predictions (560+ patients in the database). Although the TEPID database was started in order to serve as a guide to the depth of the epidural space, it was John Alfred Lee (1906–1989), who was sufﬁciently concerned about the depth that he introduced the standard 1 cm markings on the Tuohy needle (Section 9.2) in order to try and reduce the number of inadvertent dural taps (Lee 1960; Maltby 2002). The midline depth of the epidural space in the region T6–L3 decreases from above downwards, and is, typically, most superﬁcial at the the L2/3 space. The TEPID data for an average male and female are shown in Table 2.1. The predictive value of paramedian data was poor, and consequently this is no longer collected or displayed.

Table 2.1: TEPID data for midline epidural depths (cm). The epidural spaces are counted up ( ve) and down (+ve) from the bottom of the scapula (BS) in the lateral − position (or sitting). The T7/8 space is generally level with the bottom of the scapula and is therefore deﬁned as BS(0). In the UK the average male and female heights are approximately 5ft 9in (176 cms) and 5ft 4in (164 cms) respectively. The results are given as: mean(SD)[range](n)

average male average female wt 76 7 5 kg wt 67 7 5 kg ± · ± · ht 176 7 5 cm ht 165 7 5 cm ± · ± · BS(+0) T7/8 5 7(0 59) [4 5–6 7] (20) 5 5(0 66) [3 7–7 0] (35) · · · · · · · · BS(+1) T8/9 5 3(0 53) [4 5–6 5] (12) 5 0(0 60) [4 0–6 5] (14) · · · · · · · · BS(+2) T9/10 5 0(1 0) [4 0–6 5] (6) 4 9(1 2) [3 5–7 0] (11) · · · · · · · · BS(+3) T10/11 4 4(0 56) [3 5–5 2] (8) 4 0(0 54) [3 0–5 0] (11) · · · · · · · · BS(+4) T11/12 — 3 7(1 1) [3 0–4 5] (2) · · · · BS(+5) T12/L1 4 (n=1) —

The TEPID database, together with a Perl program, is freely available. After entering the patient’s height/weight/gender the program displays both the epidural data and the relevant tube data (single and double-lumen).

1Tube and EPIdural Database (TEPID). This is a collection of thoracic epidural and tube data accumulated over many years. It is freely available from http://www.nickalls.org/dick/xenon/rwdnXenon.html CHAPTER 2. EPIDURAL BLOCK RWD Nickalls 

• Lee JA (1960). Specially marked needle to facilitate epidural block. Anaesthesia; 15, 186. [cited from Maltby 2002] • Maltby JR (2002). Lee’s ‘Synopsis of Anaesthesia’ & Lee epidural needle; John Alfred Lee (1906–1989). In: Notable names in anaesthesia. (The Royal Society of Medicine Press Limited, London). p. 114–116. [ISBN 1853-155-128.]

2.2 General aspects

2.2.1 Awake or under GA? There is currently some discussion regarding whether epidurals should be performed under GA or not (following a couple of reported cases from Germany of paraplegia following epidural under GA).

• Drasner K (2004). Thoracic epidural anaesthesia: asleep at the wheal? Anesthesia & Analgesia; 99, 578–579. [editorial]

• Fischer HBJ (1998). Anaesthesia; 53, 727–729. [editorial] • Gruning T (1999). Regional anaesthesia—before or after general anaesthesia? Anaesthesia, 54, 86–87. [letter] • Kao M-C, Tsai S-K, Tsou M-Y, Lee H-K, Guo W-Y and Hu JS (2004). Paraplegia after delayed detection of inadvertent spinal cord injury during thoracic epidural catheterization in an anesthetized elderly patient. Anesthesia & Analgesia; 99, 580–583. • Wildsmith JAW & Fischer HBJ (1999). Regional anaesthesia—before or after general anaesthesia? Anaesthesia, 54, 86–87. [letter]

2.2.2 Midline approach The midline depth of the epidural space appears to decrease from above downwards in the region T6–L3, probably being most superﬁcial at the the L2/3 space. Data from our own thoracic database (TEPID; see section 2.1.1) for an average male and female are shown in Table 2.1.

2.2.3 Paramedian approach The paramedian depth of the epidural space at T7–T8 is approximately 3–5 cms. Use the depth of the lamina as a guide: the epidural space is usually 2 cm deeper than the lamina. ≤ CHAPTER 2. EPIDURAL BLOCK RWD Nickalls 

2.2.4 Reducing catheter migration / fallout At the skin Catheter fall-out rate is significantly reduced by (a) good strapping, and (b) leaving more catheter in the epidural space. I originally used to leave about 4–5 cm inside the epidural space but this was associated with a significant ‘fall-out’ rate during the first few postoperative days. Some years ago I therefore decided to experiment by having the 15 cm mark at the skin, and since then (a) none has ‘fallen-out’ as far as I am aware, and (b) no adverse effects have been noticed.

At the filter A recent letter by Picton and Das (2004) described taping the catheter to the filter (including a small redundant loop of catheter) as a good method for reducing catheter disconnection at the filter. The problem of how to proceed if the epidural catheter itself becomes disconnected from the filter is addressed in Section 2.4.1.

• Picton P and Das S (2004). Decreasing epidural failure. Anaesthesia; 59, 729.

2.2.5 Radiographic placement The following two reports describe a paramedian radiographic technique for locating the tip of the Tuohy needle, and for checking loss of resistance using radio-opaque contrast.

• Johnson T and Haslett R (2000). X-ray image intensiﬁer assisted placement of a thoracic epidural. Anaesthesia, 55, 822–823. [letter] • Johnson TW, Morgan R and Smalley P (2003). Radiographic guided epidural placement. Anaesthesia; 58, 485–486. [letter]

2.2.6 Fibreoptic guided placement • Chien-Kun Ting et al. (2010). A new technique to assist epidural needle placement: ﬁberoptic-guided insertion using two wavelengths. Anesthesiology; 112, 1128–1135. [successful pilot in pigs]

2.3 Drugs

A fairly typical intraoperative epidural dose for a thoracotomy in an adult would be approximately 100–200 µg fentanyl plus 15–20 mls 0 25 % bupivicaine during the course of the operation. One approach is to mix 200 µg fentanyl· plus 6 mls 0 25% bupivicaine into the ﬁrst 10 ml syringe, and give this initial dose over about 15–30 mins· depending on the blood pressure. In elderly patients consider reducing the dose of fentanyl. CHAPTER 2. EPIDURAL BLOCK RWD Nickalls 

The usual postoperative regimen at the City Hospital is to use a standardised pre-ﬁlled bag (500 mls) containing a mixture of fentanyl 2 mg + bupivicaine 0 125%, starting at about 5 mls/hr (range 0–10 mls/hr). These bags are kept in the recovery· room in the DDA cupboard. Typically this standard regimen is started at the begining of the operation and adjusted accordingly. An alternative system, suitable for either ITU or HDU, is to use a syringe-driver—in this case a typical regimen for an adult would be to mix 200 µg fentanyl plus 56 mls of 0 25% bupivicaine (total 60 mls), starting at about 5 mls/hr (range 0–10 mls/hr). · The ideal mixture of fentanyl and bupivicaine is somewhat controversial, and practice varies widely. The optimum concentration for epidural fentanyl was stated to be 10 µg/ml fentanyl by Welchew EA (1983), who also noted that the addition of 0 125% bupivicaine can improve the analgesia. A greater strength of bupivicaine is said not· to signiﬁcantly improve analgesia, while a lower concentration of bupivicaine appears to have no advantage over using fentanyl alone (Badner et al. 1994). A recent study by Tan et al. (2004) compared fentanyl concentrations of 2, 5, and 10 µg/ml in bupivicaine 0 1% (plain) for thoracic epidurals, found that a concentration of fentanyl 5 µg/ml gave the· optimum balance between excessive pain and excessive sedation. Clonidine was used in thoracic epidurals for laparotomy by Curatolo et al. (2000); they suggested that an optimum combination was clonidine (5 µg/hr) plus bupivicaine (9 mg/hr) plus fentanyl (21 µg/hr). The addition of adrenaline to bupivicaine and fentanyl reduced plasma fentanyl concentrations. Postoperative pain-relief algorithm: There is a comprehensive algorithm printed on a poster in the thoracic high-dependency ward. Copies can be obtained from the thoracic surgeons.

• Badner NH, Bhandari R, Komar WE (1994). Bupivicaine 0 125% improves continuous postoperative epidural fentanyl analgesia after abdominal· or thoracic surgery. Can. J. Anaesth.; 41, 387–392.

• Curatolo M, Schnider TW, Petersen-Felix S, Weiss S, Signer C, Scaramozzino P and Zbinden AM (2000). A direct search procedure to optimize combinations of epidural bupivicaine, fentanyl and clonidine for postoperative analgesia. Anesthesiology; 92, 325–337. [thoracic epidurals] • Tan CNH, Guha A, Scawn NDA, Pennefather SH and Russell GN (2004). Optimal concentration of epidural fentanyl in bupivicaine 0 1% after thoracotomy. Br. J. Anaesth.; 92, 670–674. [fentanyl 5 µg/ml was optimum]· CHAPTER 2. EPIDURAL BLOCK RWD Nickalls 

• Welchew EA (1983). The optimum concentration for epidural fentanyl. A randomised double-blind comparison with and without 1:200,000 adrenaline. Anaes- thesia; 38, 1037–1041.

2.4 Complications

2.4.1 Epidural catheter disconnection The problem of how to proceed if the epidural catheter itself becomes disconnected from the ﬁlter is addressed by Grewal, Hocking and Wildsmith (2006), as follows.

A common concern is what to do if the epidural infusion system becomes disconnected somewhere between the bacterial ﬁlter and the patient. An interesting laboratory study using deliberately contaminated catheters suggested that reconnection is safe within 8 hrs provided that the ﬂuid inside the catheter is static (or the meniscus has moved < 12 5 cm) and does not move when lifted above the level of the patient. The outside must· be soaked in 10 % povidone iodine solution, or similar, for 3 mins and allowed to dry thoroughly before up to 20 cm is cut from the end with a sterile instrument. If these conditions are not met, the catheter must be removed. Grewal, Hocking and Wildsmith (2006)

• Grewal S, Hocking G and Wildsmith JAW (2006). Epidural abscesses. [review article] Br. J. Anaesth.; 96, 292–302.

2.4.2 Abscess Literature reports of epidural abscess suggest that this complication is not uncommon (about 0 1%). Patients should be examined frequently for fever, local tenderness and neurological· deﬁcit. The excellent review by Grewal, Hocking and Wildsmith (2006) and the AAGBI (2002) guidelines should be essential reading for all.

• AAGBI (2002). Infection control in anaesthesia. (Association of Anaesthetists of Great Britain and Ireland). • Gosavi C, Bland D, Poddar R and Horst C (2004). Epidural abscess complicating insertion of epidural catheters. Br. J. Anaesth.; 92, 294. • Grewal S, Hocking G and Wildsmith JAW (2006). Epidural abscesses. [review article] Br. J. Anaesth.; 96, 292–302. [see reply by Jeffreys Horton and Evans 2006] • Jeffreys A, Horton R and Evans B (2006) Epidural abscesses. Br. J. Anaesth.; 97, 115–116. • Ng KP (1996). Complete heart block during laparotomy under combined thoracic epidural and general anaesthesia. Anaesthesia and Intensive Care; 24, 257–260. CHAPTER 2. EPIDURAL BLOCK RWD Nickalls 

• Roberts CJ (2004). Epidural abscess complicating insertion of epidural catheters. Br. J. Anaesth.; 92, 294–295.

2.4.3 Haematoma & DVT prophylaxis Low molecular weight heparin (LMWH, enoxaparin, tinzaparin) is currently used in thoracic surgery. It is given once daily in the evening in order to facilitate day-time epidurals. Peak plasma concentrations occur at 4 hours and activity persists up to 24 hours. The PT and APTT are not generally affected by therapeutic doses, so monitoring requires measurement of anti-factor Xa levels (Roberts et al. 2004; Hirsh et al. 2001). Epidural catheters should not be removed earlier than 8 hours following anticoagulation. See Mcleod and Cumming (2004) for an overview. European guidelines recommend (a) once daily dosing with LMWH, (b) 12 hr interval between injection and either epidural catheter insertion or removal (Wheatley et al. 2001).

• McLeod GA and Cumming C (2004). Thoracic epidural anaesthesia and analgesia. Continuing Education in Anaesthesia, Critical Care and Pain; 4 (No. 1), 16–19. [BJA]

• Hirsh J, Warkentin TE, Shaughnessy SG, Anand SS, Halperin Jl, Raschke R, Granger C, Ohman EM and Dalen JE (2001). Heparin and low-molecular-weight heparin: mechanisms of action, pharmacokinetics, dosing, monitoring, efﬁcacy and safety. Chest; 119 (Suppl); 64S–94S. • Horlocken TT and Heit JA (1997). Low molecular weight heparin: biochemistry, pharmacology, perioperative prophylaxis regimens and guidelines for regional anaesthetic management. Anaesthesia and Analgesia; 85, 874–885. • Kearon C and Hirsh J (1997). Management of anticoagulation before and after elective surgery. NEJM; 336, 1506–1511. • Roberts HR, Monroe DM and Escobar MA (2004). Current concepts of hemostasis: implications for therapy. Anesthesiology; 100, 722–730.

2.5 Paravertebral block

Naja, Ziade et al. (2004) suggest that the paravertebral space is divided into a potential anterior (extrapleural) and posterior (sub-endothoracic) compartments by a so-called endothoracic fascia, and that such spaces inﬂuence drug spread—see reply letters by Fitzgerald and Harmon (2004) and by Naja and Lonnqvist¨ (2004) for more references and discussion. CHAPTER 2. EPIDURAL BLOCK RWD Nickalls 

As regards efﬁcacy, it seems that a paravertebral block compares well with an epidural block (see Casati et al. 2006; Mathews and Govenden 1989).

• Casati A, Alessandrini P, Nuzzi M, Litti E et al. (2006). A prospective, randomised, blinded comparison between continuous thoracic paravertebral and epidural infusion of 0 2% ropivacaine after lung resection surgery. European Journal of Anaesthesiol- ogy·; 23, 999–1004. [paravertebral is just as effective as epidural for analgesia, and has fewer haemodynamic complications] • Conacher ID and Kokri M (1987). Postoperative paravertebral blocks for thoracic surgery. Br. J. Anaesth.; 59, 155–161. • Eason MJ and Wyatt R (1979). Paravertebral thoracic block—a reappraisal. Anaes- thesia; 34, 638–642.

• Fitzgerald K, Harmon D et al. (2004). Thoracic paravertebral blockage. Anaesthesia; 59, 1028–1029. [letter: reply to Naja et al. 2004] • Govenden V and Mathews PJ (1988). Percutaneous placement of paravertebral catheters during thoracotomy. Anaesthesia; 43, 256.

• Loader J and Ford P (2009). Thoracic paravertebral block. Update in Anaesthesia (June 2009), p. 4–7. http://update.anaesthesiologists.org/2009/ [good practical overview] • Karmakar MK (2001). Thoracic paravertebral block. Anesthesiology; 95, 771–780. [review]

• Mathews PJ and Govenden V (1989). Comparison of continuous paravertebral and extradural infusions of bupivicaine for pain relief after thoracotomy. Br. J. Anaesth.; 62, 204–205. [paravertebrals were associated with less hypotension and less urine retention; analgesia was the same in both groups] • Naja MZ, Ziade MF, Rajab El et al. (2004). Varying anatomical injection points within the thoracic paravertebral space: effect on spread of solution and nerve blockade. Anaesthesia; 59, 459–463. [see interesting reply letter by Lang and Saito (2005): Anaesthesia; 60, 930–931] • Naja MZ et al. (2005). Distance between the skin and the thoracic paravertebral space. Anaesthesia; 60, 680–684. [median depth was 55 mm; the depth was least in the T4–T8 zone] • Naja MZ, Lonnqvist¨ PA et al. (2004). Thoracic paravertebral blockage. Anaesthesia; 59, 1028–1029. [letter: reply to Fitzgerald et al. 2004] CHAPTER 2. EPIDURAL BLOCK RWD Nickalls 

• Richardson J, Cheema SPS, Hawkins J and Sabanathan S (1996). Thoracic paravertebral space location. Anaesthesia; 51, 137–139. [used pressure measurement during needle advancement; sudden pressure fall as needle traverses the superior costo-transverse ligament] 3 Tracheostomy & related airway problems

A tracheostomy is like a snake—it can rear up and bite you when you least expect it.

HIS is a path littered with unforeseen hazard. Some basic guidelines can therefore be useful since most of us anaesthetise relatively few patients with, or for, a T tracheostomy. The key skills to learn are (a) changing a tracheostomy (Section 3.6) and (b) bronchoscopy (Chapter5). • Intensive Care Society UK (2008). Standards for the care of adult patients with a temporary tracheostomy. pp. 53. • Lesmo A and Ripamonti D (2010). Anatomical particularities and difficulty in tracheostomy: three case reports. Minerva Anestesiologica; 76, 649–652. [experience using the Fantoni Trans-Laryngeal Technique (TLT)] • Russell C and Matta B (2004). Tracheostomy: a multiprofessional handbook. (Cambridge University Press), 392 pp. ISBN 1–84110–1524. • Ernst A and Mehta C [Eds.] (2003). Artificial airways (2003); Clinics in Chest Medicine; 24 (September). [chapters: Endotracheal tubes / Tracheotomy: application and timing / Percuta- neous dilational tracheotomy techniques / Percutaneous tracheostomy—special considerations / Techniques of surgical tracheostomy / Comparison of surgical and percutaneous dilational tracheostomy / Minitracheostomy / The Montgomery T-tube tracheal stent / Acute complications of artificial airways / Long-term complications of artificial airways / Long-term care of the tracheostomy patient / Transtracheal oxygen catheters / Management of hypoxemia during flexible bronchoscopy]

40 CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

3.1 Introduction

As a general rule, whenever there is a problem with a tracheostomy (in theatre or on a ward) have a very low threshold for inspecting the position of the tracheostomy with a fibrescope—either with the intubating fibrescope or with the usual ‘large’ fibrescope. Many significant complications arising from a ‘blind’ manoeuvre would have been avoided completely if only a fibrescope had been used initially. Simple visualisation of the trachea in order to check the position of the tracheostomy does not require local anaesthesia, since this generally can be done by positioning the fibrescope just at the tracheal-end of the tracheostomy, i.e., without needing to touch the tracheal mucosa. However, sometimes it is advantageous to give some local anaesthetic to allow more freedom with the fibrescope. The following simple technique generally works very well.

3.1.1 Local anaesthetic for fibreoptic bronchoscopy of the trachea A reasonably effective adult dose is 80 mg plain lignocaine (2 mls of 4% lignocaine) which can either be blown down the bronchoscope, or down the dilator 1 of a Portex ‘Seldinger’ Mini-Trac (since this has a very useful Luer connector) with the tip positioned well down the tracheostomy. Take a 20 ml syringe (with a straight Luer connector so it can be pushed into the fibrescope inject port) and pull the plunger out to the 20 ml position; now inject 2 mls of 4% lignocaine into the empty syringe via the nozzle and then hold it vertically (nozzle down); now connect the 20 ml syringe vertically into the inject-port of the fibrescope (tip now positioned at the tracheal-end of the tracheostomy) and inject quickly (ideally at the end of expiration) all 20 mls (2 mls lignocaine + 18 mls air). This will deliver the lignocaine as a fine spray throughout the trachea, and usually gives very effective local analgesia above the carina.

3.2 Tracheostomy tubes

There is a huge range of tracheostomy tubes—cuffed and uncuffed, fenestrated & non- fenestrated; standard forms with and without inner-tubes (e.g., Portex, Tracoe); specialised forms (e.g., Montgomery tube (Section 3.9), Mini-Trac, double-lumen), as well as various attachments (speaking valves, humidiﬁers). Most of these are well described by Russell and Matta (2004). When purchasing standard tracheostomy tubes it is useful to consider only those for which the number deﬁning the tube ‘size’ is the same as the internal diameter of the

1In this case use a 20 ml syringe having a Luer-lock connector (available in ITU), as you generally have to push the syringe plunger in with signiﬁcant force (since the Portex Mini-Trac dilator has a very narrow channel). Unless you lock the syringe nozzle onto the Luer connector of the dilator it will probably disconnect as you inject, owing to the relatively high resistance to ﬂow. CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

inner-tube, as is standard with endo-tracheal tubes. The tracheostomy tubes currently used by the City Hospital are Portex and Tracoe, both of which follow this rule.

3.2.1 Portex2 (Smiths Medical) (Smiths Medical, Hythe, Kent, UK; tel: +44-(0)-1303-260-551) The Portex brand (Smiths Medical) includes a percutaneous dilation kit (UniPerc), as well as a range of tracheostomy tubes: 1. Non-fenestrated versions which are intended for short-term use only (usually changed weekly). The internal and external diameter speciﬁcations for the standard tracheostomy tube are given in Table 3.1. 2. Adjustable ﬂange versions (e.g., the UniPerc) for use in obese patients. 3. A left double-lumen tracheostomy tube.

3.2.2 Tracoe (Kapitex Healthcare Ltd., Kapitex House, 1 Sandbeck Way, Wetherby, West Yorkshire LS22-7GH, UK; tel: 01937–580211. http://www.kapitex.com) The Tracoe tracheostomy tubes used at the City Hospital (TRACOE twist MODEL 302) are fenestrated (multiple small holes) polyurethane radio-opaque low-pressure cuffed tubes, intended for medium-term use (up to 31 days). Note that neither the duration nor latex status seems to be speciﬁed in their documentation. The twist-lock connection is fully ‘locked’ when the two arrow heads are opposite one another. Each Tracoe box includes • Outer tube with swivelling neck-plate • A removable non-fenestrated inner-tube (white 15 mm connector; for suctioning and ventilation).

• A removable fenestrated inner-tube (blue 15 mm connector; for spontaneous respiration weaning) • Obturator (for insertion) and neck strap While Tracoe do make decannulation plugs and speaking valves, these are not included in the package (i.e., they are ‘extras’). These speaking-valves and other ‘extras’ are stocked by ITU. The Passey-Muir clinical information pack relating to tracheostomy tubes and speaking-valves is available from Kapitex Healthcare.

2In 1940 Sydney Leader, a dental surgeon at the Dental Hospital, London, set up a company based in his ﬂat in Great Portland Street. His company, which was called Portland Plastics Ltd., was later renamed Portex Ltd. in 1967 (see: Russell CA (1996). Developments in thermoplastic tracheal tubes. In: Essays on the History of Anaesthesia. (Royal Society of Medicine Press Ltd., London). p. 94–97). CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

3.2.3R usch¨ (Rusch¨ UK Ltd.,High Wycombe, Bucks, HP12 3NB. UK; tel: 01494–532761). Make a left and right 39 Fr double-lumen tracheostomy tube. Three intratracheal lengths are available (75, 85, 95 mm).

3.2.4 Moore tube (Kapitex Healthcare Ltd., Kapitex House, 1 Sandbeck Way, Wetherby, West Yorkshire LS22-7GH, UK; tel: 01937–580211. http://www.kapitex.com) The Moore tracheostomy tube (Boston Medical Products, Westborough, MA, USA) is a soft and ﬂexible long (115 mm) silicone non-cuffed tracheostomy (with a similar inner tube), which is typically used to maintain tracheostomy access (in a spontaneously breathing patient) following removal of a long adjustable-ﬂange tracheostomy. It can be easily cut to the appropriate length. Two sizes are available: 6 (ID 6.6 mm; OD 11 mm) and 8 (ID 7.5 mm; OD 12 mm).

3.3 Tracheostomy—when?

Commonly at 7–10 days or so, depending on likely duration of ITU care. A failed trial of extubation is a common indication for tracheostomy. Patients with concomitant respiratory disease tend to have a tracheostomy performed at an early stage. While a tracheostomy greatly facilitates nursing and respiratory care and shortens ITU stay, it does not generally reduce hospital stay as it tends to lengthen HDU stay, since most hospital wards cannot accommodate tracheostomy patients.

• Grifﬁths J, Barber VS, Morgan I and Young JD (2005). Systematic review and meta-analysis of studies of the timing of tracheostomy in adult patients undergoing artiﬁcial ventilation. Br. Med. J. (2005); 330, 1243 [see also letters: 331, 404–405]

3.4 Percutaneous tracheostomy

Percutaneous tracheostomy owes its popularity to the introduction of the ‘Blue-Rhino’ (William Cook Europe) modiﬁcation of the dilational technique by the American surgeon Pasquale Ciaglia in 1985 (Eggert and Jerwood 2003). Careful patient selection is important, and there is a signiﬁcant learning curve. While a percutaneous tracheostomy tends to have lower rate of long-term complications (e.g., tracheal stenosis) than a surgical tracheostomy, the early ‘percutaneous’ complication rate (e.g., bleeding, tracheal damage, pneumothorax) tends to be higher. Percutaneous complications, when they do occur, tend to be serious. The advantages of prior ultrasound scanning for aberrant vessels is suggested by several authors—see Gwilyn and Cooney CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

(2004), Shlugman et al. (2003), Toni et al. (2003). Damage to the posterior tracheal wall is an ever present danger—see Madden et al. (2004) on one approach to this problem using a covered stent. For a good overview see the handbook by Paw and Bodenham (2004); for details of two meta-analysis studies see the article by Eggert and Jerwood (2003). For experience with the Fantoni Trans-Laryngeal Technique see Lesmo and Ripamonti (2010).

• Ciaglia P, Firsching R and Syniec C (1985). Elective percutaneous dilational tracheostomy. Chest; 87, 715–719. [from Eggert and Jerwood 2003] • Dulguerov P, Gysin C, Perneger TV and Chevrolet J-C (1999). Percutaneous or surgical tracheostomy: a meta-analysis. Critical Care Medicine; 27, 1617–1625. • Eggert S and Jerwood C (2003). Percutaneous tracheostomy. Br. J. Anaesth. — CEPD Reviews; 8, 139–142. [good review of two recent meta-analysis studies] • Fikkers BG, van Veen JA, Kooloos JG et al. (2004). [surgical] Emphysema and pneumothorax after percutaneous tracheostomy: case report and anatomic study. Chest; 125, 1805–1814. [highlights danger of the fenestration in the outer tube damaging the posterior wall mucosa]

• Gwilyn S and Cooney A (2004). Acute fatal haemorrhage during percutaneous dilational tracheostomy. Br. J. Anaesth.; 92, 298. [letter] • Lesmo A and Ripamonti D (2010). Anatomical particularities and difﬁculty in tracheostomy: three case reports. Minerva Anestesiologica; 76, 649–652. [experience using the Fantoni Trans-Laryngeal Technique (TLT)]

• Madden BP, Sheth A, Ho TBL and McAnulty G (2004). Novel approach to management of a posterior tracheal tear complicating percutaneous tracheostomy. Br. J. Anaesth.; 92, 437–439. [see also reply letter by Fritz, Buerschaper and Wolf (2004); 93, 598]

• Paw HGW and Bodenham AR (2004). Percutaneous tracheostomy: a practical handbook. (Cambridge University Press). • Phukan DK and Andrzejowski J (2004). Percutaneous tracheostomy: a guidewire complication. Br. J. Anaesth.; 92, 891–893. [fracturing of the J-wire causing damage to the mucosa]

• Ryan DW and Kilner AJ (2003). Another death after percutaneous dilational tracheostomy. Br. J. Anaesth.; 91, 925–926. • Shlugman D, Satya-Krishna R and Loh L (2003). Acute fatal haemorrhage during percutaneous dilational tracheostomy. Br. J. Anaesth.; 90, 517–520. CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

• Toni R, Della Casa C, Mosca S, Malaguti A, Castorina S and Roti E (2003). An- thropological variations in the anatomy of the human thyroid arteries. Thyroid; 13, 183–192. • Walz MK et al. (1998). Percutaneous dilational tracheostomy—early results and long-term outcome in 326 critically ill patients. Intensive Care Medicine; 24, 685–690. [2 deaths in 326 patients. They also review the literature, revealing a further 7 deaths in 2034 patients (total death rate 1/263 ! Causes of death:- bleeding; obstruction & hypoxia]

• William Cook Europe. Ciaglia Blue RhinoTM : instructions for use. (Denmark), 2000; 91 pp. [from Eggert and Jerwood 2003]

3.5 Surgical tracheostomy

Assuming the patient already has a single-lumen endotracheal tube in place, then the main considerations are as follows (Rogers et al. 2001). • Make sure the cuff is not damaged by the surgeon. To this end it is recommended that the endo-tracheal tube be first pushed down close to the carina, using a fibreoptic bronchoscope to position the tube safely. Consider changing the endo-tracheal tube if it is too short to reach the carina. • Be alert to the potential fire risk (see recommendations below). Although flammable anaesthetic agents are no longer used in the UK, fires in the operating theatre continue to be an occasional hazard, particularly with operations on the airway. Thankfully, most such fires are evanescent and cause no harm, but unfortunately deaths do still occur. For example, in two separate fatalities reported by Stouffer (see Rogers et al. 2001), the fires spread uncontrollably with alarming speed, and in one case the operating theatre had to be evacuated. Interestingly, tracheostomy fires tend not to be as catastrophic as other airway fires, possibly because the tracheostomy acts as a vent.

3.5.1 Recommendations The following recommendations for anaesthesia for surgical tracheostomy are from the article by Rogers et al. (2001). The emphasis is on (a) avoiding a ﬁre, and (b) avoiding surgical damage to the ETT cuff. Note the interesting idea of instilling carbon dioxide directly into the tracheostomy wound described by Mani et al. (2007). 1. All theatre staff should be aware that an airway ﬁre may occur during tracheostomy. CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

• Have a fire extinguisher immediately available. It should be mounted inside the operating theatre near the entrance. In practice a carbon-dioxide fire-extinguisher will be the usual choice. Halon fire extinguishers are significantly better for operating theatre fires, but their use is declining owing to environmental concerns. • Have a bowl of saline and wet drapes available on the surgical instrument trolley at all times. • Have a self-filling ventilation bag (e.g., Ambu bag) available for ventilating the patient with room air. • Do not use nitrous oxide or any of the other flammable/explosive anaesthetic agents.

2. Use a single-lumen endotracheal tube which is long enough to allow the tip to be advanced to the carina (the carina is approximately 24–25 cms from the teeth in an average male). If a single-lumen endotracheal tube is in situ and is too short to reach the carina, then change it for one with a suitable length. If a double-lumen endotracheal tube (or a nasotracheal tube) is already in situ then change it for a single-lumen tube before tracheostomy. 3. Use saline to inﬂate the endotracheal cuff. Make sure there is no leak of anaesthetic gases past the endotracheal cuff.

4. Use the lowest safe FIO2 in either nitrogen (air/oxygen mixture) or helium. 5. If the tracheostomy wound is significantly deep (e.g., in an obese patient), use a suction device to clear any build up of diathermy products from within the wound. 6. Before the trachea is opened, advance the endotracheal tube down the trachea so the tip is close to the carina, in order to minimise the likelihood of damage to the cuff when the trachea is incised. Use a fibreoptic bronchoscope to position the tip of the endotracheal tube close to the carina, and mark the tube at the teeth when correctly positioned—this will serve as a useful position guide later if the surgeon fails to place the tracheostomy and you need to push the tube down quickly to get the cuff below the tracheal hole. 7. Incise the trachea using either a scalpel, scissors, or a harmonic knife. Do not use diathermy to cut through the trachea. 8. Once the trachea has been opened and the surgeon is ready to insert the tracheostomy tube, stop ventilating, deflate the endotracheal tube cuff and withdraw the endotracheal tube carefully under direct vision until the tip is just above the tracheal hole (do not withdraw the tube any further at this stage). Be prepared to push the endotracheal tube back down the trachea to secure the airway if there are any difficulties, either while inserting the tracheostomy, or during the initial ventilation CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

through the tracheostomy. Remember to keep the oral ETT in situ so you can put the bronchoscope down it (after suctioning) to inspect the tracheostomy. 9. Once the tracheostomy tube is secure in the trachea, inflate the tracheostomy cuff and suck out the tube using a suction catheter, checking that the suction tube passes easily through the whole length of the tube. If this is satisfactory then commence ventilation through the tracheostomy. However, always check that the tracheostomy tube is correctly located/positioned within the trachea using a fibreoptic bronchoscope— either now (if in doubt), or at the end of the procedure—remember to keep the oral ETT in situ so you can put the bronchoscope down it. This is primarily to check that the new tube is not partially obstructed or in a false passage (note that being able to pass a suction catheter does not exclude these possibilities), and to check that the end of the tracheostomy tube is not too close to the carina (this can occasionally be a problem with a long adjustable-flange tracheostomy tube). 10. If any difficulties arise with the tracheostomy tube, remove the tracheostomy tube and advance the endotracheal tube down the trachea so that the cuff lies below the tracheal hole. Have a long endotracheal bougie available (e.g., a gum-elastic bougie), to facilitate advancing the endotracheal tube in case of difficulties. Sometimes, if the tube is soft, it may bend in the pharynx and fail to go down into the trachea when you push it, in which case consider placing a bougie down the tube to stiffen it; a long gum-elastic bougie can also be useful in this situation.

11. If the endotracheal tube cuff has been damaged and the leak is significant, then adequate ventilation can usually be maintained by (a) using large tidal volumes, (b) pushing swabs firmly onto the tracheostomy hole to occlude the leak. Consider using a wide plastic occlusive dressing (e.g., OpSite or Tegaderm) under the swabs to reduce the leak further. Control the leak intermittantly as necessary between surgical attempts to insert the tracheostomy tube. Consider re-intubating if necessary.3 Hazard note: If a significant leak occurs during a tracheostomy when using a pressure-cycled ventilator (e.g., an ITU ventilator in BIPAB mode), the ventilator may fail to cycle and not ventilate the patient. Have a low threshold for switching to manual bag-ventilation whenever there is a leak in this particular setting. 12. In the event of fire, immediately disconnect the patient from the anaesthetic machine, switch off the anaesthetic gas flow, disconnect the gas pipelines, and ventilate with air using a self-inflating bag. Use an airway filter if there is smoke in the theatre. Consider flushing saline down the endotracheal tube to extinguish any intraluminal fire. Consider removing or changing the tube to minimise the inhalation of toxic products of combustion and spread of fire into the tracheobronchial tree. However,

3The neck will likely be well extended and without a pillow at this stage, and so you may need to insert a pillow to get good visualisation of the larynx. Also, use an uncut tube in order to make sure you will be able to get the cuff below the tracheostomy hole, and check the position relative to the carina with a ﬁbrescope. CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

changing the tube may be more risky than leaving it in if the patient was previously difficult to intubate, or the airway has become oedematous. 13. Finally: It is important to check the position of a fenestrated tracheostomy with the fibreoptic-bronchoscope by viewing it from above—from the larynx—in order to check whether the whole of the fenestration, or fenestration holes, of the outer tube are within the trachea. In practice this is most easily done via the original oral ETT—which should still be in situ for just this purpose. Note that the Tracoe tracheostomies have a total of nine small fenestrations symmetrically arranged in a circle on the larynx side of the tube; the three holes forming the vertical diameter should all be visible through the fibreoptic bronchoscope. In obese patients the distance between the skin and the anterior tracheal wall is often too big for the tracheostomy, resulting in some of the fenestration(s) being outside the trachea. The potential consequence of this, especially for ventilated patients, is that air may track back up the tracheostomy (between the inner and outer tubes) and out through the fenestration and into the tissue spaces of the neck, resulting in surgical emphysema. If the neck is too big, then use an adjustable flange tracheostomy instead.

References • ASA Taskforce (2008). Practice advisory for the prevention and management of operating room ﬁres. [a report by the American Society of Anesthesiologists Task Force on operating room ﬁres] Anesthesiology; 108, 786–801.

• ECRI (2003). A clinician’s guide to surgical fires: how they occur, how to prevent them, and how to put them out [guidance article]. Health Devices; 32(1), 5–24. From: Sentinel Event Alert, Issue 29: June 24, 2003. (Joint Commission on Accreditation of Healthcare Organisations) http://www.jointcommission.org/sentinel_ event_alert_issue_29_preventing_surgical_fires/ • Eipe N and Choudhrie A (2005). Airway fires: gas-bugs providing the fuel? Anesth. & Analg.; 101, 1563–1564. [letter] • Hamza M and Loeb RG (2000). Fire in the operating room. Journal of Clinical Monitoring and Computing; 16, 317–320. • Mani N, Malik V, Brewis C and Gray R (2007). Prevention of airway fire during a tracheostomy — a further precaution. Annals of the Royal College of Surgeons of England; 89, 818. [describe using an NG-tube via the larynx to pass carbon dioxide into the trachea close to the tracheostomy site] • Molodecka J and Long TMW (1992). Difficult tracheostomy and the ‘adjustable flange tracheostomy tube’. Today’s Anaesthetist; 7, 100. CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

• Rogers ML, Nickalls RWD, Brackenbury ET, Salama FD, Beattie MG and Perks AGB. (2001). Airway fire during tracheostomy: a review for surgeons and anaesthetists. Annals of the Royal College of Surgeons of England; 83, 376–380. • Wolf GL (2000). Danger from OR fires still a serious problem. Journal of Clinical Monitoring and Computing; 16, 237–238 [APSF Newsletter] • Yardley IE and Donaldson LJ (2010). Surgical fires, a clear and present danger. The Surgeon; 8, 87–92. [review]

A useful list of references relating to ‘Fire prevention and safety during surgical procedures’ can be found at: http://www.valleylabeducation.org/fire/pages/fire-read. html

3.6 Changing a tracheostomy tube

See also Section 3.11 Typically a tracheostomy is changed because it is either time-expired,4 damaged (hole in the cuff), or because a different size or format is now required. Occasionally a tracheostomy has to be changed as an emergency procedure owing to malposition, in which case particular care has to be taken as regards bronchoscopic visualisation and railroading over a suitable guide (bougie, oxygenating catheter, bronchoscope etc.). The main practical considerations are (a) whether the tracheostomy was percutaneous or surgical, (b) the external diameter of the existing tracheostomy tube, (c) whether the patient is ventilated or breathing spontaneously, (d) whether the patient is awake or anaesthetised, (e) how long since tracheostomy formation or last tube change, (f) whether malposition is suspected. Percutaneous: Since a percutaneous tracheostomy tube is often tightly held by the skin it may be quite difﬁcult to remove and replace. In view of this it is important to use only tracheostomies having an inner-tube, in order to avoid the necessity of having to change it soon after when the patient goes to the ward, or to facilitate weaning. It is important to be aware of the external diameter of the existing tracheostomy and aim to replace it with one having the same or slightly smaller external diameter if the skin is tight around it. Surgical: Since a surgically placed tracheostomy tube is usually only loosely held by the skin, changing the tracheostomy tube rarely presents a problem with regard to the size of the new tube, and it can usually be replaced (even with a slightly larger tube) without difﬁculty.

4A tracheostomy without an inner-tube (e.g., Portex) should be changed weekly; a tracheostomy with an inner-tube (e.g., Tracoe) should be changed monthly. CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

Table 3.1: Portex and Tracoe tracheostomy tubes

PORTEX TRACOEtwist (fenestrated) Size ID mm OD mm ID mm OD mm (inner-tube) (outer-tube) 4 4 0 4 0 7 2 · · · 5 5 0 5 0 8 6 · · · 6 6 0 8 3 6 0 9 2 · · · · 7 7 0 10 5 7 0 10 4 · · · · 8 8 0 11 9 8 0 11 4 · · · · 8 Long 8 0 11 0 — — · · 9 9 0 13 3 9 0 12 5 · · · · 10 10 0 14 0 10 0 13 8 · · · · 10 Long 10 0 13 8 — — · ·

3.6.1 Preparation • Always check the chest x-ray, listen to the chest, check pulse & blood pressure, oxygen saturation, inspired oxygen, and make sure there is venous access (ﬂush an existing cannula to make sure it is working). Check the notes to see (a) if the patient was difﬁcult to intubate through the mouth, (b) if previous tracheostomy changes were problematic, and (c) if there is any drug allergy. Have drugs and intubation equipment available. • Check whether the tracheostomy was percutaneous or surgical.

• Check the size and make of the existing tracheostomy tube. Check its external diameter—if this is smaller than that of the one you propose to replace it with then you may have difﬁculties, particularly if the tracheostomy was made percutaneously (usually this is not a problem if the tracheostomy was a ‘surgical’ one). The external diameters of tracheostomy tubes are given in Table 3.1.

• Check if the tracheostomy has a cuff (look for the pilot balloon). If there is no cuff then the patient may be breathing via the tracheostomy and via the nose/mouth (this will have implications for pre-oxygenation—see next Section). • Check the status of the inner-tube. If a fenestrated inner-tube is in situ (Tracoe blue connector) ﬁrst change it for the non-fenestrated version (Tracoe white connector), CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

since this (a) allows you to ventilate the patient if you need to, and (b) allows easy passage for a suction catheter/bougie since there is no hole for it to get stuck against.

3.6.2 Changing the tube • If the patient is awake, explain exactly what you are going to do. • Preoxygenate the patient. If there is no cuff (or it is damaged) then remember to preoxygenate via both the mouth (with a mask) and the tube. If there is a cuff then preoxygenate via a catheter mount at the tracheostomy, and check that you can gently ventilate the patient by hand, inﬂating the cuff as necessary. If there is no cuff, then preoxygenate both via a catheter mount at the tracheostomy and with a face mask, as the patient may be breathing via both routes. • Suck out the tracheostomy checking that the suction catheter passes easily into the trachea. If there is a lot of secretions, then continue suctioning until it is as dry as possible before changing the tube. • Have a large (orange tipped) suction catheter available for railroading the new tube. • Extend the patient’s neck using a supporting pillow under the shoulders for maximum access.

• Prepare the new tracheostomy tube by ﬁrst checking the cuff is intact, and then deﬂate the cuff fully and lubricate the cuff with some KY-jelly. Make sure that you have the non-fenestrated inner-tube inside, and that the suction catheter (for railroading) passes easily through the middle (use KY-jelly as necessary). Use the largest diameter suction catheter you can (orange is usually best) which will pass through the non-fenestrated inner-tube, and remember to cut the connector off the suction catheter. Have a smaller size tracheostomy available just in case. • Remove the neck ties holding the tracheostomy in place. • Have an assistant hold the patient’s head as a precaution. Have an assistant ready with a suction device for sucking out the stoma if necessary once the tracheostomy is out, since removing the tracheostomy often releases a lot of secretions into the stoma. • Insert the railroading catheter through the existing tracheostomy and pass it a good way into the trachea. • Remove the existing tracheostomy (remember to let the cuff down), suction the stoma as necessary, and railroad the new one into position. Be prepared to use a smaller tracheostomy if necessary. CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

• Once the new tracheostomy is in place inﬂate the cuff and check (a) you can pass a suction catheter easily into the trachea, (b) that you can ventilate the patient easily and that there is no cuff leak, (c) if the patient is breathing spontaneously check that the bag moves easily, and (d) listen carefully to the chest.

• If there are difﬁculties consider (a) removing the new tracheostomy and trying again after suctioning, (b) railroading the tube over a bronchoscope, (c) intubating through the mouth if necessary.

3.6.3 Check the position bronchoscopically • Always check at the end of the procedure that the new tracheostomy tube is correctly located/positioned within the trachea using a bronchoscope—check you can see the carina. This is the only reliable way of conﬁrming that the new tube is not partially obstructed or in a false passage (note that being able to pass a suction catheter does not exclude these possibilities). Note the distance between the end of the tracheostomy and the carina. • Finally, do a chest X-ray, and make an entry in the medical notes (size, method, problems, and bronchoscopy ﬁndings).

3.7 Anaesthetising a patient with a laryngectomy

Patients with a well established laryngectomy will of course be familiar with tracheostomy use and its management. Consequently, I ﬁnd the most convenient approach is to insert a cuffed tracheostomy on the ward preoperatively on the day of the operation, thus allowing plenty of time for the patient to get used to the tracheostomy before arriving in the anaesthetic room. This greatly facilitates induction and reduces the incidence of coughing.

3.8 Anaesthetising a patient with a tracheostomy in situ

A few basic precautions are worth bearing in mind. Be prepared to change the tracheostomy if necessary (Section 3.6), and always have a bronchoscope handy so you can check position/location if necessary. Before inducing the patient make sure you can actually ventilate the patient through the tracheostomy; i.e., check whether (a) the tracheostomy has a working cuff, and (b) if there is an inner-tube, make sure it is the non-fenestrated one.

• Check the notes to see if the patient was difﬁcult to intubate through the mouth. • Check the notes to see whether the tracheostomy was surgical (usually easy to replace with the same or larger size), or percutaneous (usually more difﬁcult to change; may need a smaller size available). CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

• Check the tracheostomy itself carefully to determine (a) the manufacturer, (b) the size, (c) whether it has a cuff (look for the pilot balloon), (d) is the inner-tube fenestrated or not? (remove it and see if there is a posterior hole in it), (e) is the inner-tube ‘locked’ in position? (check that the two small arrows (Tracoe) are aligned; Shiley tracheostomy tubes have two small dots which need to be aligned). Turn the inner tube clockwise to lock it. • Check you have a new (unopened) 5 same-size same-make tracheostomy tube available. For tracheostomy tubes having an inner-tube this precaution will also guarantee that you have to hand the all-important non-fenestrated inner-tube (white connector for both Shiley and Tracoe tubes). If the tracheostomy is a percutaneous one, then have the next size smaller also available. • Since a spontaneously-breathing patient may come to theatre with a fenestrated inner-tube in situ (Shiley green connector; Tracoe blue connector) remember to check before induction the status of the inner-tube (remove it and see if it has a posterior hole), and change to the non-fenestrated version (white connector for both Shiley and Tracoe) if necessary—this is why it is important to have a new unopened tracheostomy tube of the same size immediately available in theatre. Note that if you induce a patient with a fenestrated inner-tube in situ you may well not be able to ventilate the patient adequately owing to the huge leak into the pharynx which will become apparent as soon as you try to ventilate the patient. • If the patient comes to theatre with a fenestrated inner-tube in situ, do any suctioning after ﬁrst changing to a non-fenestrated inner-tube (white connector), as otherwise the suction catheter may get held up by the fenestration in the inner-tube. In the case of a Shiley tracheostomy tube the catheter may even pass through the large single fenestration in the outer tube and damage the posterior wall of the trachea. Note that Tracoe tracheostomy tubes have multiple small holes in the outer tube which prevent this problem. • Check that the patient’s tracheostomy is a cuffed one (i.e., look for the pilot balloon) and that the cuff is intact (check with a bag that there is no leak, and that you can (gently) ventilate the patient by hand). If the cuff leaks consider replacing the tracheostomy before induction (but remember, a fenestrated inner-tube will also cause a leak—see above). • Have some large (orange tipped) suction catheters available (for railroading) in case you need to change the tracheostomy tube. • Disconnection hazard: Since the anaesthesia circuit connects directly on to the inner-tube of the tracheostomy, then if the alignment arrows (or dots) at the connection become misaligned during the operation (e.g., if the patient is turned laterally),

5Check that the plastic bag inside the box is unopened—it is not uncommon (unfortunately) for someone to have opened it and taken the non-fenestrated inner-tube! CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

the anaesthesia circuit may rotate (anticlockwise) sufﬁciently to unlock the inner- tube, and may cause the inner-tube to fall out resulting in a disconnection. It is therefore extremely important to make sure that the tracheostomy and the alignment arrows (or dots) are clearly visible at all times, and that no anticlockwise torque is exerted by the circuit on the inner-tube.

3.8.1 Postoperative management While patients with a tracheostomy generally wake up very smoothly, they do present an unusual airway risk with regard to aspiration should they vomit. Consequently, the recovery staff need to be familiar with tracheostomy care, and be aware of the aspiration risk. A useful approach is to protect the airway using a catheter mount (on the tracheostomy), and have it directed to one side.

3.9 Montgomery T-tube placement

These T-tubes are used to stent a collapsing trachea. Surgical placement is via the trachea, and is usually extremely difﬁcult (may take up to 1 hour). Anaesthesia ideally requires two anaesthetists—one to manage the airway and jet-ventilation, and one to control TIVA and relaxation (see Section 5.7.2). Note that once the tube is in place it is then not possible to use an endotracheal tube for ventilation, and so the options are either an LMA, bag & mask, or perhaps jet-ventilation via a catheter.

• Ernst A and Mehta C [Eds.] (2003). Artiﬁcial airways. Clinics in Chest Medicine, 24 (September). (WB Saunders Company, London) [includes a chapter on the Montgomery T-tube tracheal stent] • Guha A, Mostafa SM and Kendall JB (2001). The Montgomery T-tube: anaesthetic problems and solutions. Br. J. Anaesth.; 87, 787–790 [excellent article]

3.10 Difﬁcult airway & trans-tracheal needle ventilation

See also Section 5.7.4 for references regarding Sanders jet ventilation via endotracheal tubes and rigid bronchoscopes.

• Benumof JL (1999). Airway exchange catheter: simple concept, potentially great danger [editorial] Anesthesiology; 91, 342–344. • Debenham TR (1985). Emergency transtracheal ventilation in anaesthesia or casualty department. Anaesthesia; 40, 599-560. [describes use of a standard IV ﬂuid giving- set—cut off the drip chamber and insert the sharp point (which is usually inserted into the infusion bag) into the trachea, and then connect the oxygen to the drip chamber using some connector] CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

• Gerig HJ, Schnider T and Heidegger T (2005). Prophylactic transtracheal catheterisation in the management of patients with anticipated difficult airways: a case series. Anaesthesia; 60, 801–805. [see excellent reply by Higgs and Vijayanand, pp. 1245–1246 (7 refs)] • Kaiser EF, Seschachar AM and Popovich MJ (2001). Tracheostomy tube replacement: role of the airway exchange catheter. Anesthesiology; 94, 718–719 [letter reply to Benumof 1999] • Layman P (1996). Difficult intubation. Today’s Anaesthetist; April, p. 52 [letter describing his technique of elective trans-tracheal (crico-thyroid) needle placement under local anaesthesia prior to a gas induction or difficult intubation. This letter cites the following three references.] • Layman P (1983). Trans-tracheal ventilation in oral surgery. Annals of the Royal College of Surgeons; 65, 318–320. • Layman P (1983). By-passing a problem airway. Anaesthesia; 38, 478–480. • Layman P (1983). An alternative to blind nasal intubation. Anaesthesia; 38, 165. • Mentzelopoulos SD and Tzouf MJ (2002). Anesthesia for tracheal and endobronchial interventions. Current Opinion in Anesthesiology; 15, 85–94. • Paw HGW and Sharma S (2006). Cricothyroidotomy; a short-term measure for elective ventilation in a patient with challenging neck anatomy. Anaesthesia & Intensive Care ; 34 (June), 384–387. [used the Melker cuffed device (Cook); 9 refs]

3.11 Miscellaneous problems

You may sometimes be called to see a patient whose tracheostomy tube has developed some ‘problem’. In general, the problem is either obstruction (partial or total), an air leak, or the tube has come out slightly and cannot be re-sited. If in doubt bronchoscope down the tracheostomy to check alignment and position. If the patient is paralysed & ventilated and the problem cannot be ﬁxed quickly, then consider reintubating through the mouth using an uncut 6 tube and advance the tube so it is just below the stoma (taking care not to inadvertently intubate a main bronchus 7),

6Uncut—since the tube must be long enough to get the cuff below the stoma. 7This is a very common error, and all too easy to make when using a long (uncut) tube in an emergency situation. Unfortunately, if you are intubating orally in order to overcome an obstructed tracheostomy (and are already wondering whether the tracheostomy tube has made a false passage), and then you discover the new oral tube seems to be obstructed as well, it is easy to wrongly assume that the cause is somehow related to the original tracheostomy problem and fail to appreciate that this new obstruction is simply due to the uncut oral tube being too far down. Checking the tube distance at the teeth is the best clue, since even a quick bronchoscopy at this stage may well be confusing (for example, showing strange and unfamiliar anatomy of small lower-lobe basal bronchi) unless you are already considering the possibility of the tube being too far down. CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

and then bronchoscope to check position in relation to the carina. If you have to bag the patient on a mask after the tracheostomy has been removed, then cover the hole with a wide plastic occlusive dressing (e.g., OpSite, Tegaderm) and ask someone to press on it to keep it in place and make it air-tight. If oral intubation is difﬁcult, consider intubating through the tracheostomy stoma, railroading over a bougie if necessary—stop as soon as the cuff is in the trachea, since you will be very close to the carina—and bronchoscope to check position. If the patient is breathing spontaneously and the problem cannot be ﬁxed easily, then consider removing the tracheostomy and railroading a new one. Consider oxygenating using both a face mask and a tracheostomy circuit, since the patient may be breathing through both routes.

3.11.1 Obstruction The commonest presenting problem is difficulty to pass a suction catheter.8 Any suggestion from the nursing staff that there are difficulties with suctioning must be taken seriously and investigated urgently. It is essential to use a bronchoscope in such cases in order to exclude partial (or even total) obstruction due either to malposition (e.g., where the tip of the tracheostomy may be only partially within the tracheal lumen), or to dried secretions.9 Remove any valve attachment (e.g. speaking valve etc) connected to the tracheostomy. Remove the inner-tube and check the lumen is patent. Check whether a suction catheter can be passed easily; check air movement with a bag (note that one can often pass a suction catheter and see bag movement even in cases of severe partial obstruction). Consider the cuff—this may be overinflated and obstructing the end (unlikely though as the cuff will be made of plastic and not rubber)—and see if letting the cuff down makes any difference. Consider malposition, especially if recent tracheostomy, recent tracheostomy change, or if the tracheostomy flanges do not lie flush with the skin. Sometimes simply releasing the retaining straps completely and observing whether the tracheostomy flanges sit nicely on the skin or not (sometimes this manoeuvre reveals a malpositioned tracheostomy being forced into an apparently normal position by the straps). Finally, consider removing the tracheostomy tube altogether if necessary. Always inspect with a bronchoscope.

• Kazi ST, Ali MA and Donohoe BO (2006). Accidental oro-endtracheostomy intubation. Anaesthesia, 61, 918. [death following tracheal obstruction, owing to failure of oral intubation—the oral ETT made an undetected anterior false passage at the tracheostomy stoma: importance of inspecting and then railroading over a fibrescope even with oral intubation if difficulties occur; may have overcome the problem if had fibrescope down ETT for guidance, or had railroaded the tracheostomy over a fibrescope initially]

8It is quite alarming in ITU how often ETTs are found to be partially obstructed, even after quite short periods of intubation. Even moderate secretions (and especially with thick secretions) should alert you to the posibility of impending obstruction, and to consider pre-emptive check-bronchoscopy and tube change if necessary. 9Note that ability to pass a suction catheter does not exclude signiﬁcant obstruction due to dried secretions. CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

• McGurie G and El-Beheiry H (2001). Loss of the airway during tracheostomy: rescue oxygenation and re-establishment of the airway. Canadian Journal of Anesthesia; 48, 697–700. [from Kazi et al. 2006] • McNamara J and Chisholm DG (1996). Use of a ﬁbreoptic intubating laryngoscope to replace a misplaced tracheostomy tube. Anaesthesia, 51, 894. [from Kazi et al. 2006] • Mirza S and Cameron DS (2001). The tracheostomy tube change: a review of techniques. Hospital Medicine; 62, 158–63. [from Kazi et al. 2006]

• Rajendram R and McGuire N (2006). Repositioning a displaced tracheostomy tube with an Aintree intubation catheter mounted on a ﬁbre-optic bronchoscope. Br. J. Anaesth.; 97, 576–579.

3.11.2 Difficulty inserting the inner tube Just occasionally, in a long term tracheostomy patient on a ward, the inner tube becomes difficult to insert. The most likely causes are (a) wrong size inner tube, (b) deformed inner tube etc. Try a new inner tube from a new tracheostomy package. Otherwise, consider inspecting the tube fenestrations with a fibreoptic bronchoscope (from the inside without the inner tube in) and also checking whether the tracheostomy is seated correctly on the skin. If the outer tube is not in sufficiently far, it may be that some of the more superficial holes are outside the trachea, in which case inspecting these from the inside with the bronchoscope reveals that the superficial holes appear pink (outside the trachea), while the deep ones appear black (inside the trachea). Tissue growing in through the holes may be enough to make it difficult to insert the inner tube. The solution is either to push the tracheostomy in fully, or possibly, just change the tracheostomy. This sort of problem arises because the tracheostomy has come out slightly on the ward, and remained not properly seated on the skin for several days or more. Although the bronchoscope and light-source can be taken to the ward, it is usually more practical to bring the patient to the ITU for investigation.

3.11.3 Air leak Consider a damaged cuff, poor position of the tracheostomy, wrong inner-tube (e.g., trying to ventilate a patient with a fenestrated inner-tube), or tracheostomy being too small (cuff leaks even when fully inflated). Finally, consider untying the straps and looking at the natural position of the tube and its flange in relation to the neck. Occasionally this reveals an obviously malpositioned tube, with the flange not sitting on the skin; the tracheostomy being forced into an apparently normal looking position by tight straps. CHAPTER 3. TRACHEOSTOMY & RELATED AIRWAY PROBLEMS RWD Nickalls 

3.11.4 Tracheostomy recently removed Its not uncommon for a patient whose tracheostomy has recently been removed (decannu- lated) to experience renewed secretion or airway problems, and require a new tracheostomy to facilitate suction, bronchoscopy and airway management. If the interval since decannulation is less than about one week then it is generally a simple matter to insert a new tracheostomy since there is usually still a hole, albeit small, at this stage. Since the aim is typically to facilitate suctioning, then occasionally just a Portex Mini-Trac may sufﬁce, but generally a small tracheostomy (say, size 7) is the minimum requirement,10 at least initially. Note that for ward use, the tracheostomy must have an inner-tube.11 Both the Portex ‘Seldinger’ Mini-Trac dilator,12 and also the blue rhino dilator,13 are extremely useful tools to have handy when dealing with this problem.

10Note that while a size 7 will allow tracheal inspection/visualisation with the small ‘intubating’ fibrescope (available from theatres), a size 8 tracheostomy is the smallest which will allow you to use the full-size suctioning fibrescope. 11A patient with a tracheostomy which does not have an inner-tube must be managed on HDU/ITU since this form of tracheostomy can easily get blocked by dried secretions. 12This has a very useful Luer connector and hence allows you to inject local anaesthetic down it directly into the trachea via even the smallest tracheal orifice. I have even used it in this way down a malpositioned tracheostomy tube (see Section 3.1.1). 13This is in the percutaneous tracheostomy pack, and can be used to further dilate the tracheal orifice if necessary. 4 Lung anatomy

HE thoracic anaesthetists’ interest in anatomy relates mainly to thoracic epidurals, bronchoscopy and tube positioning. While epidural anatomy is well catered for T (see Section 2.1), copies of the primary texts on the relevant lung anatomy (Brock 1942–1944, Brock 1954, Boyden 1955, Hollinger and Johnston 1957, Kavuru and Mehta 2004) are difﬁcult to ﬁnd.1 I am pleased, therefore, to be able to include (with permission) some diagrams and plates from Brock 2 (1942–1944, 1954), which contain quite the best lung anatomy diagrams for thoracic anaesthetists that I have found so far, not withstanding the excellent diagrams in Kavuru and Mehta (2004). See also references to the anatomy of the epidural space (Section 2.1), radial artery (Section 9.5.2), central veins (Section 9.6.4), and bronchoscopic anatomy (Chapter5). Other useful texts are Burwell and Jones (1996), Ellis et al. (2004), Itoh et al. (2004), Minnich and Mathisen (2007), Deslauriers (2007).

4.1 Anatomical terms 3

Alveolus (Gk): Diminutive of alveus (cavity) alveolus (small cavity). Azygos (Gk): a (without) + zugon (yoke) azygos→ (not yoked), i.e., not a paired structure. A non-paired body part, especially a vein.→ Azygos vein: A vein of the right superior thorax draining into the superior vena cava. Azygos lobe: A lung zone separated by an indentation (typically from above down) formed by an azygos vein and its superior mesentery (‘meso-azygos’). The so-called ‘azygos lobe’ is not a true lobe (it does not have a constant bronchus and vessels). First described by HA Wrisberg (1737–1808) in 1778—hence the ‘lobule of Wrisberg’ (Brock 1954, p. 216).

1Copies are available in the British Library, London. 2Lord RC Brock; thoracic surgeon at Guy’s Hospital, London. 3Modiﬁed from: The New Sh. Oxf. Eng. Dict. (1993); Jaeger EC and Page IH (1953), A source-book of medical terms (CC Thomas, Springﬁeld, Illinois, USA); Field EJ and Harrison RJ (1968), Anatomical terms: their origin and derivation, 3rd ed. (W Heffer & Sons, Cambridge, UK.)

59 CHAPTER 4. LUNG ANATOMY RWD Nickalls 

Bougie (Fr): bougie (candle). Bronchus (Gk): brogkhos, bronchos (windpipe). Bulla (L): bulla (bubble-like). Carina (L): carina (keel of a boat); carinatus (keel-like). The last ring of the trachea has a keel-like inferior projection carried back in the fork between the major bronchi. Chyle (Gk): chyl (juice). Clavicle (Gk): kleis (a key). (L): clavis; dim. clavicular (a bar for closing a window). Some suggest it is named from the Greek owing to its fancied resemblance to a key. However, it is most likely derived from the Latin because it resembles a curved window fastener, and joins or “locks the shoulder girdle to the body,” The Roman clavis was also an S-shaped metal bar used to strike bells. Costal (L): costa (rib). Cricoid (Gk): krikos (a ring). The shape of the cricoid cartilage is like a signet-ring. Diaphragm (Gk): dia (through, across) + phragma (fence). Effusion (L): effundere (pour out); effusus is past participle of effundere. Empyema (Gk): empyesis (suppuration), empyematos (abscess). Fissure (L): fissus (split, cloven). Hiatus (L): hiatus (a gap). Hilum (L): hilum (a trifle, a small thing). Point of attachment; point where an organ is attached by vessels & nerves. Lingula (L): lingere (to lick); lingula (tongue-like). Part of the left upper lobe (equivalent to the right middle lobe), consisting of superior and inferior segments supplied via the lingula bronchus. It is occasionally separated by a partial fissure from the rest of the upper lobe. The following is from Brock (1954, p. 82). The term “lingula” really refers to the tip or tongue-like projection of the lowest and most anterior part of the left upper lobe, but it is justifiable to make use of the name to describe the whole portion of which the lingula is really but a part. . . . Its chief practical importance lies in the frequency of which it is involved by bronchiectasis in common with the left lower lobe. Lung (Anglo-Saxon): lungen (light). The lungs were originally known as ‘lights’ because they were so light in weight. Manubrium (L): manubrium (a handle). The manubrium sterni is shaped like the handle of a sword. Mediastinum (L): Probably from per medium tensum (that which is tight down the middle); hence between the two lungs. Oesophagus (L): -phagos (eating) ysophagus. From the Greek oisophagos (gullet). Pharynx, pharyngeal (Gk): pharyngos→ (throat). Phrenic (Gk): phren (the mind). Taken to mean the seat of emotion around the heart, hence associated with the diaphragm. Pleura (Gk): pleura (side, rib). Sternum (Gk): sternon (the male breast). Stomach (Fr): estomac, stomaque; (L) stomachus; (Gk) stomakhos. CHAPTER 4. LUNG ANATOMY RWD Nickalls 

Thorax (Gk): thorax, thorakos (the chest). Thymus (Gk): thymos (thyme; an aromatic herb). The thymus gland is so named owing to a resemblance to a bunch of thyme. Throid (Gk): thyra (a door) thyreos (shield with a notch for the chin). Apparently the name ‘thyroid’ was introduced→ in 1646 by Thomas Wharton (1616–1673), English anatomist and physician at St. Thomas’ Hospital, London. Trachea (L): trachia (rough). (Gk): trachys. Also: Aspera arteria (air conduit). Vertebra (L): vertebra (a joint). From verto (I turn).

4.2 History of lung anatomy 4

Lung anatomy was initially investigated using the process of injecting coloured wax into the bronchi and vessels—a technique largely developed by Jan Swammerdam 5 (1637– 1680). Two types of wax models were developed: the so-called ‘wax corrosion’ cast, and the later wax-injected dried dissections; details of these techniques were often included in early anatomy books.6 A fine example of an early wax corrosion cast in a glass bell-jar is shown in the portrait of William Hunter (1718–1783) at the Royal College of Surgeons, London (Tompsett, 1965). The process of establishing the true basic anatomy of the lung was very slow, the first serious attempt to describe the anatomy in any useful detail being that by the famous Swiss anatomist Christoph Theodor Aeby (1835–1885). However, the models he worked from were poor and he made significant errors—based on comparative anatomy—which were perpetuated through his writings (Aeby 1880). Fortunately, these errors were soon revealed 7 by the pathologist William Ewart, whose careful work led to the modern concept of the bronchopulmonary segment.

4.2.1 Bronchopulmonary segment William Ewart (1848–1929) was a pathologist at the Brompton Hospital, London, and is generally regarded as the ‘father of segmental anatomy’ (Tompsett, 1965). Ewart was uneasy about the somewhat casual approach to lung anatomy, as he tells us in his treatise (Ewart 1889):

Moreover, a suspicion had arisen in my mind that the present deﬁciencies in our anatomical knowledge . . . might perhaps be held responsible for the halting . . . in the development of Pulmonary Surgery, contrasting with the steady progress made in the surgery of other organs. Ewart 1889 (from Tompsett 1965)

4For overviews see Tompsett (1965), Boyden (1955), Sealy et al. (1993), Fell and Pearson (2007). 5Tompsett (1965). 6Pole (1790) was one of the ﬁrst to include details of the injection process for making anatomical models. 7This is highlighted in the title of Ewart’s book (Ewart, 1889) in which he includes the following: ‘. . . with a criticism of Professor Aeby’s views on the bronchial tree . . . ’ CHAPTER 4. LUNG ANATOMY RWD Nickalls 

Ewart’s magniﬁcent achievement was the realisation that the lung consists of a number of functionally and anatomically separate components, which he termed ‘respiratory units’. He summarises his key ﬁndings regarding the bronchi as follows:

(3) The bronchial tubes do not anastomose. Each lobe therefore receives from the main bronchus a distinct air-supply. The same principle of separate supply extends, within the lobe, as far as the infundibula. This absence of anastomosis is physiologically of great moment. . . . Respiratory districts — At the root of the lung the conditions are very different, since the primary, secondary, and tertiary branches from the main bronchus radiate towards the periphery for considerable distances, without bearing any lobules. Within each lobe, large groups of lobules being served by separate bronchi are thus kept in practical isolation from each other as regards their air-supply. Each of these sublobar groups may be considered as forming a separate respiratory district, within which the tidal air, or the bronchial contents in general, may, perhaps, be capable of interchange from lobule to lobule. . . . A knowledge of the situation, within each lobe of the respiratory districts of which it is composed, is likely to be valuable to the clinical physician. But an attempt to deﬁne their anatomical boundaries would with advantage be postponed until a full description of the bronchial tree had supplied a sound basis for the subdivision of each lobe into its lobular groups. Ewart 1889, p. 65–66. Ewart died 8 in 1929, only a few years before the surgical signiﬁcance of his ‘respiratory districts’ became widely appreciated. Just three years later Kramer and Glass (1932) extended Ewart’s concept, viewing his respiratory districts as ‘pathological units’. Glass (1933) then coined the term bronchopulmonary segment, and soon after Churchill and Belsey (1939) demonstrated the surgical resectability of bronchopulmonary segments— establishing that they were effectively also ‘surgical’ units. A new era of thoracic surgery was being ushered in by developments in anatomy, as Boyden (1955) describes:

The modern period begins with the suggestive studies of Kramer and Glass (1932), the one a bronchoscopist,9 the other a surgical resident at the Mount Sinai Hospital in New York. Pressed by surgical colleagues for a better localization of lung abscesses, including a knowledge of where to enter the chest for drainage, Glass proposed “to establish a smaller and more accurate unit of localization than the lobe.” Unaware of Ewart’s pioneer work, he named the bronchopulmonary segment and stated that it represented “not only an anatomic but a pathologic unit:” this, by virtue of the fact that its orifice occupies a prominent position in the lobar bronchus and therefore is vulnerable to aspiration of infected material. Besides giving us the now generally accepted name for this unit, Glass injected the main divisions of each lobar bronchus with different “colored fluid dyes,” thereby providing the first diagrams of surface distribution. Relationship to the thoracic cage was determined from bronchograms of

8Obituary of Ewart W. (1848–1929). Lancet; 217, 408–409 [from Boyden 1955] 9Dr Rudolph Kramer: see also Kirschner (2003). CHAPTER 4. LUNG ANATOMY RWD Nickalls 

the lung. Altogether, eleven segments were recognized. In general these corresponded to Ewart’s districts, except that the two subsegments of the pectoral district and two subdivisions of the middle lobe were given the status of segments. Boyden 1955, p. 14

These were important and exciting times for thoracic surgery. Kirschner (2003) puts these great achievements in context as follows:

. . . Recognized today as a momentous advance in the surgical anatomy of the lung, this laid the groundwork for the localization and precise drainage of lung abscess, and the anatomical basis for precise pulmonary resection. Kirschner (2003), p. 329.

4.3 Lung development & embryology

The recent advent of molecular biology and gene expression promises a seriously detailed understanding of the development of the lung, as indicated by a recent paper by Metzger et al. (2008). Using a mouse model they reveal that—to use a computer programming analogy—lung development appears to be largely under the control of a molecular master branching-program coordinating three slaves (branching-subroutines). The development of lung branching is therefore perceived as proceeding according to a relatively ﬁxed sequence of repeating functional molecular branching-instructions, controlled by a relatively small number of genes operating at branch tips. The editorial relating to this paper summarises the interest in this area, as follows:

Whether a master branch generator controlling a select few slave subroutines represents a general developmental strategy that has been reused over evolutionary time in different branched organs, remains an intriguing possibility. Also, solving the speciﬁc problem of gas diffusion as a limit on size, and discovering how simpliﬁed, genetically controlled branching routines interact with physical and biological factors to direct complex yet reproducible patterns of development, will be matters of great interest. To quote Charles Darwin as interpreted by biologist Sean Carroll,10 they will aid our understanding of how “endless forms most beautiful”11 have evolved from a relatively simple tool-box of genetic modules. Warburton (2008).

10SB Carroll (2007). Endless forms most beautiful: the new science of Evo Devo and the making of the animal kingdom, (Norton, New York) ISBN 987-0393060164. 11This is a quote from the last paragraph of Darwin’s The origin of species (1859): ‘There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the ﬁxed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved’ (Nickalls, 2009). CHAPTER 4. LUNG ANATOMY RWD Nickalls 

4.4 Nomenclature

In May 1949 the nomenclature of the bronchi and segments was standardised by the Thoracic Society (BTS, 1950). For discussion see Boyden (1953).

4.4.1 Right lung The bronchus to the right upper lobe should no longer be called the ‘eparterial’ bronchus— use ‘upper lobe bronchus’ instead. The part of the bronchus between the upper lobe bronchus and the middle lobe bronchus should be called the ‘upper part of the right main bronchus’, and the lower part should be called the ‘lower part of the right main bronchus’. Upper lobe 1. Apical bronchus and segment 2. Posterior bronchus and segment 3. Anterior bronchus and segment Middle lobe 4. Lateral bronchus and segment 5. Medial bronchus and segment Lower lobe 6. Apical bronchus and segment 7. Medial basal (cardiac) bronchus and segment 8. Anterior basal bronchus and segment 9. Lateral basal bronchus and segment 10. Posterior basal bronchus and segment

4.4.2 Left lung (a) No segment 7, (b) the upper lobe has an upper division and a lower (lingula) division, (c) use the term ‘lingula’ in preference to ‘lower division’ Upper lobe — upper division bronchus 1. Apical bronchus and segment 2. Posterior bronchus and segment 3. Anterior bronchus and segment — lingula (lower division) bronchus 4. Superior bronchus and segment 5. Inferior bronchus and segment Lower lobe 6. Apical bronchus and segment 8. Anterior basal bronchus and segment 9. Lateral basal bronchus and segment 10. Posterior basal bronchus and segment CHAPTER 4. LUNG ANATOMY RWD Nickalls 

4.5 Carina

The safe positioning of an endotracheal tube relies not only on an understanding of the applied anatomy and an awareness of the likely position of the carina, but also on an appreciation of those factors which can move the carina relative to the end of the tube. In particular, the distance of the tip of a tube from the teeth is a very useful guide for recognising when a tube is likely to be close to the carina, or even beyond it. The surface marking of the carina in a supine patient is the manubrio-sternal angle (Burwell and Jones 1996, Ellis et al. 2004, Minnich and Mathisen 2007).

Table 4.1: Approximate distances in an average supine adult male.

Teeth vocal cords 15 cm −→Trachea 10 cm Carina left-subcarina 5 cm Carina right-upper−→ lobe oriﬁce 2 5 cm −→ · Teeth carina 25 cm Teeth −→left-subcarina 30 cm −→

4.5.1 Factors moving the carina The distance of the carina from the teeth varies quite markedly with (a) neck position ( 2 cm with flexion/extension), (b) body position (supine, lateral, lithotomy, Trende- lenberg)± particularly in obese patients or those with a large or distended abdomen, and (c) body height/weight. The length of the trachea (and hence position of the carina) is greatly influenced by the position of the diaphragm.12 While the carina is typically about 24 cms from the teeth in a lean supine adult male of normal height, it can be as little as 18 cms in an equivalent obese patient in lithotomy. The recent letter by Greenland (2004) gives some useful references regarding anatomy and how to position an endotracheal tube safely. With a single-lumen tube it is not uncommon for the tip to be inadvertently positioned at or below the carina in short and/or obese patients; the risk increasing further when such patients are head-down and/or in lithotomy. The risk is even more significant if there is also raised intra-abdominal pressure, as in laparoscopy (Nishikawa et al. 2004). Furthermore, in short patients the larynx-intubation guide-marks on standard endotracheal tubes may locate the tip of the tube too close to the carina (Chong et al. 2006; Cherng et al. 2002). Appreciating the factors which influence the position of the carina is especially important when positioning double-lumen tubes, since in this setting even small movements of the carina may not only jeopardise the adequacy of lung isolation and ventilation (see

12Hence: ‘what moves the diaphragm also moves the carina’ (see Section 7.4). CHAPTER 4. LUNG ANATOMY RWD Nickalls 

Section 7.4), but can equally well lead to obstruction and lobar collapse. The TEPID database (see Section 6.4.3) is a good predictor of the distance to the carina in supine patients, and has proved to be a useful practical guide in this regard. It is important to have a low threshold for using a ﬁbreoptic bronchoscope to check the tube position following any change in the patient’s position. Note that tube/carina problems are particularly likely to arise in the ITU, owing to the fact that patients ventilated in the ITU are subject to the combination of (a) PEEP, and (b) being nursed in a 45 deg semi-sitting position. This combination of factors typically results in the carina being signiﬁcantly further away from its usual supine location. For example, when trainees bronchoscope such patients they often express surprise at how far away the carina is. One must take care to avoid inadvertently positioning the ETT close to the carina if the patient is in a semi-sitting position, since later, when the patient is supine (for nursing or other reasons), the carina may rise too close to the end of the tube. The expected number of cms from the teeth is usually the best initial guide to ETT position in this setting.

4.6 Right-upper lobe oriﬁce

Typically the right-upper lobe (RUL) orifice is 2–2 5 cm below the carina, and is often positioned very slightly anterio-lateral (i.e., a right-sided· endo-bronchial tube often needs to be rotated slightly anticlockwise in order to align the side hole with the RUL orifice). The location of the RUL orifice relative to the carina is somewhat variable, and can even originate from the trachea directly (see below).

4.7 Aberrant bronchus

Supernumerary bronchus: A bronchus supplying a (supernumerary) segment which is additional to the usual bronchus (supplying its usual lung zone or segments). It is most frequently associated with the right upper lobe, and typically arises laterally from the right side of the trachea, about 2 cm above the normal right upper-lobe bronchus (Brock 1954, p. 201). For clinical implications see Section 7.9.3. Displaced bronchus: A bronchus which is otherwise normal (i.e., supplies its usual lung zone or segment), but is displaced (up or down) from its usual location. Displaced bronchi are much more common than supernumerary bronchi. The commonest displaced bronchus is an upward displacement of the apical bronchus of the right upper lobe. On the left side, a not uncommon displaced bronchus is that of the medial basal (‘cardiac’) bronchus, arising medially from the left lower-lobe bronchus above the origin of the anterior basal bronchus—exactly analogous to the ‘cardiac’ bronchus of the right lower lobe (Brock 1954, p. 207). For clinical implications see Section 7.9.3. CHAPTER 4. LUNG ANATOMY RWD Nickalls 

Figure 4.1: Drawing of a dissection to show the relation of the ﬁssures of the right lung, and to demonstrate the depth from the skin surface of the termination of the ﬁssure (From Brock (1942–1944), with permission) CHAPTER 4. LUNG ANATOMY RWD Nickalls 

Figure 4.2: Similar drawing of the left lung to show the ﬁssure (From Brock (1942–1944), with permission) CHAPTER 4. LUNG ANATOMY RWD Nickalls 

Figure 4.3: Top: Chest diagrams to show the level of the lobes and interlobar ﬁssures of the lungs as seen from the front and back. Bottom: Similar diagrams to show the bronchopulmonary segments. The lateral subsegments of the right upper lobe are indicated by broken lines (From Brock (1942–1944), with permission) CHAPTER 4. LUNG ANATOMY RWD Nickalls 

Figure 4.4: Top: Chest diagrams to show the bronchopulmonary segments as seen in the lateral view. The lateral subsegments of the right upper lobe are indicated by broken lines. Bottom: Similar diagrams to show the bronchi supplying the bronchopulmonary segments (From Brock (1942–1944), with permission) CHAPTER 4. LUNG ANATOMY RWD Nickalls  Brock (1942–1944), with permission) From : Lateral and medial views in which the individual segments have been Right lung Figure 4.5: injected with coloured gelatin. ( CHAPTER 4. LUNG ANATOMY RWD Nickalls  Brock (1942–1944), with permission) From : Lateral and medial views in which the individual segments have been Left lung Figure 4.6: injected with coloured gelatin. ( CHAPTER 4. LUNG ANATOMY RWD Nickalls 

Figure 4.7: Drawings of normal bronchi as seen at bronchoscopy in a supine patient. How- ever, in my experience the left upper bronchial oriﬁce in the left lower bronchi drawing is generally seen much closer to the 10–11 o’clock position—compare with Figures 5.1 and 5.2. See Section 4.4 for the more modern nomenclature. (From Brock (1942–1944), with permission). CHAPTER 4. LUNG ANATOMY RWD Nickalls 

4.8 References

• Anatomy Atlases: see the link from the Virtual Hospital website: http://www.uihealthcare.com/vh/ • Aeby C (1880). Der Bronchialbaum der Saugethiere¨ und des Menschen. Nebst Be- merkungen uber¨ den Bronchialbaum der Vogel¨ und Reptilien. (Wilhelm Engelmann, Leipzig). [from: Boyden 1955]

• Atkinson RS, Rushman GB and Lee JA (1987). A synopsis of anaesthesia. (IOP Publishing Ltd, Bristol, UK) • BTS (1950). Nomenclature of broncho-pulmonary anatomy; an international nomenclature accepted by the Thoracic Society. Thorax; 5, 222–228. [from Brock, 1954] • Boyden EA (1949). A synthesis of the prevailling patterns of the bronchopulmonary segments in the light of their variations. Dis. Chest; 15, 657–668. • Boyden EA (1953). A critique of the international nomenclature on bronchopulmonary segments. Dis. Chest; 23, 266–269. • Boyden EA (1955). Segmental anatomy of the lung. (McGraw-Hill Book Co. Ltd., London, UK). • Brock RC (1942). The level of the interlobar ﬁssures of the lungs. Guy’s Hospital Reports; 91, 140–146; • Brock RC (1942–1944). Observations on the anatomy of the bronchial tree, with special reference to the surgery of lung abscess. Guy’s Hospital Reports; Part I . Introduction. 91, 111–130; Part II. The left upper lobe. 92, 26–37; Part III. The middle lobe. 92, 82–88; Part IV. The lower lobes. 92, 123–144; Part V. The whole lung: anomalies and compound abscesses. 93, 90–107.

• Brock RC (1954). The anatomy of the bronchial tree. 2nd. ed., (Oxford University Press, Oxford, UK) [ﬁrst published in Guy’s Hospital Reports (1942–1944), 91–93] • Brock RC, Hodgkiss F and Jones HO (1942). Bronchial embolism and posture in relation to lung abscess. Guy’s Hospital Reports; 91, 131–139; • Burwell DR and Jones JG (1996). The airways and anaesthesia; I: anatomy, physiology and ﬂuid mechanics. Anaesthesia; 51, 849–857 (September issue). II: pathophysiology. Anaesthesia; 51, 943–955 (October issue). CHAPTER 4. LUNG ANATOMY RWD Nickalls 

• Cherng CH, Wong CS, Hsu CH and Ho ST (2002). Airway length in adults: estimation of the optimal endotracheal tube length for orotracheal intubation. Journal of Clinical Anesthesia; 14, 271–274. • Chong DYC, Greenland KB, Tan ST, Irwin MG and Hung CT (2006). The clinical implication of the vocal chords-carina distance in anaesthetized Chinese adults during orotracheal intubation. Br. J. Anaesth.; 97, 489–495. • Churchill ED and Belsey R (1939). Segmental pneumonectomy in bronchiectasis. Annals of Surgery; 109, 481–499. [from Patnaik and Saha 1999]

• Deslauriers J [Ed.] (2007). Thoracic anatomy, Part I —Chest wall, airway, lungs. Thoracic Surgery Clinics; 17 (November), 443–666 (Elsevier, Inc) [chapters: Historical perspectives of thoracic anatomy / Surface anatomy and surface landmarks for thoracic surgery / Muscles of the chest wall / The anatomy of the ribs and the sternum and their relationship to chest wall structure and function / The intercostal space / The costovertebral angle / Anatomy of the thoracic outlet / Correlative anatomy for the sternum and ribs, costovertebral angle, chest wall muscles and intercostal spaces, thoracic outlet / Anatomy of the neck and cervi- cothoracic junction / The glottis and subglottis: an otolaryngologist’s perspective / Glottis and subglottis: a thoracic surgeon’s perspective / Anatomy of the trachea, carina, and bronchi / Lobes, ﬁssures, and bronchopulmonary segments / Pulmonary vascular system and pulmonary hilum / Bronchial arteries and lymphatics of the lung / Correlative anatomy for thoracic inlet; glottis and subglottis; trachea, carina, and main bronchi; lobes, ﬁssures, and segments; hilum and pulmonary vascular system; bronchial arteries and lymphatics] • Eagle CCP (1992). The relationship between a person’s height and appropriate endotracheal tube length. Anaesthesia and Intensive Care; 20, 156–160.

• Ellis H, Feldman S and Harrop-Grifﬁths (2004). Anatomy for anaesthetists; 8th ed. (Blackwell Scientiﬁc Publications, Oxford, UK). • Ewart W (1889). The bronchi and pulmonary blood-vessels: their anatomy and nomenclature; with a criticism of Professor Aeby’s views on the bronchial tree of mammalia and of man. (JA Churchill, London, UK). [Obituary of Ewart W. (1848–1929). Lancet; 217, 408–409 [from Boyden 1955]] • Fell SC and Pearson FG (2007). Historical perspectives of thoracic anatomy. Tho- racic Surgery Clinics; 17 (November), 443–448. (Elsevier, Inc) [In: Deslauriers J [Ed.] (2007)].

• Goodman LR, Conrardy P, Laing F and Singer MM (1976). Radiographic evaluation of endotracheal tube position. American Journal of Roentgenology; 127, 433–434. [tube can move 2 cm with ﬂexion and extension of the neck] ± CHAPTER 4. LUNG ANATOMY RWD Nickalls 

• Glass A (1934). The bronchopulmonary segment with special reference to putrid lung abscess. Am. J. Roentgenol.; 31, 328–332. • Greenland K (2004). A response to ‘Auscultation of the chest after tracheal intubation by: Kahn AW and Morris S, Anaesthesia; v59, 626–62’. Anaesthesia; 59, 929–930. • Hannallah MS, Benumof JL and Ruttiman UE (1995). The relationship between left mainstem bronchial diameter and patient size. J. Cardiothorac. Vasc. Anesth.; 9, 119–121. [see also editorial pp. 117–118; and article pp. 784–785] • Hollinger PH and Johnston KC (1957). Clinical aspects of congenital anomalies of the trachea and bronchi. Dis. Chest; 31, 613–621. http://chestjournal. chestpubs.org/content/31/6/613.full.pdf • Itoh H, Nishino M and Hatabu H (2004). Architecture of the lung; morphology and function. J. Thoracic Imaging; 19, 221–227. [lung parenchyma; macroscopic and histological detail] • Joseph JE and Merendino KA (1957). The dimensional interrelationships of the major components of the human tracheobronchial tree. Surg. Gynecol. Obstet.; 105, 210–214. • Kavuru MS and Mehta AC (2004). Applied anatomy of the airways. In: Wang et al. (2004), Chapter 5, p 36–38. [contains many excellent colour diagrams showing the relationship between the cardio-pulmonary vessels and the bronchial tree] • Kirschner PA (2003). The history of thoracic surgery at Mount Sinai. The Mount Sinai Journal of Medicine; 70, No. 5, October 2003. (http://mountsinai.site- ym.com/) • Kramer R and Glass A (1932). Bronchoscopic localization of lung abscess. Annals of Otology, Rhinology and Laryngology; 41, 1210–1220. • Mackenzie M and MacLeod K (2003). Repeated inadvertent endobronchial intubation during laparoscopy. Br. J. Anaesth.; 91, 297–298. • Merendino KA and Kiriluk LB (1954). Human measurements involved in tracheobronchial resection and reconstruction procedures; report of a case of bronchial adenoma. Surgery; 35 (Apr), 590–597. [ISSN 0039-6060] • Metzger RJ, Klein OD, Martin GR and Krasnow MA (2008). The branching program of mouse lung development. Nature; 453 (5 June),745–756. [editorial: p. 733–735 (Warburton 2008)] • Minnich DJ and Mathisen DJ (2007). Anatomy of the trachea, carina and bronchi. Thoracic Surgery Clinics; 17, 571–585. CHAPTER 4. LUNG ANATOMY RWD Nickalls 

• Netter Images. This is a commercial site (Elsevier) giving high quality medical illustrations. For their excellent ﬁgure of bronchopulmonary segments see http: //www.netterimages.com/image/4426.htm

• Nickalls RWD (2009). Evolution of the end of ORIGIN. Science; 326, 801.

• Nishikawa K. Nagashima C, Shimodate Y, Igarashi M and Namili A (2004). Migration of the endotracheal tube during laparoscopy-assisted abdominal surgery in young and elderly patients. Can. J. Anaesth.; 51, 1053–1054. [migration was greater in the elderly, owing to effects of age on lung volumes.]

• Patnaik VVG and Saha JC (1999). Incidence of subsuperior bronchus — morpho- logical and bronchographic study. J. Anat. Soc. India; 48, 99–104. • Pole T (1790). The anatomical instructor, (W Darton & Co., London); (2nd ed 1824). • Sealy WC, Connally SR and Dalton ML (1993). Naming the bronchopulmonary segments and the development of pulmonary surgery. Annals of Thoracic Surgery; 55, 184–188. • Tompsett DH (1965). The bronchopulmonary segments. Medical History; April, 9 (2), 177–181. http://www.ncbi.nlm.nih.gov/pmc/journals/228/ • Wang Ko-Pen, Mehta AC and Turner JF (2004). Flexible bronchoscopy. 2nd ed. (Blackwell Publishing, UK) • Warburton D (2008). Order in the lung. Nature; 453 (5 June), 733–735 [editorial to Metzger et al. (2008)]. 5 Fibreoptic bronchoscopy

IBREOPTIC bronchoscopy is an essential tool for viewing bronchial anatomy, and for facilitating correct placement of single and double-lumen endotracheal tubes, F bronchial blockers and tracheostomies. In the Intensive Care Unit 1 it is also used for bronchoalveolar lavage (BAL), secretion control and to facilitate lung re-expansion. Facility with a fibreoptic bronchoscope and familiarity with the endobronchial anatomy should be essential for all anaesthetists. Note the recent bronchoscopy issue of Clinics in Chest Medicine edited by Mehta (2010). Fibreoptic brochoscopy should, in my view, be a much more routine procedure in the general operating room, since in my experience there are many general surgery patients who stand to benefit from a quick peri-operative bronchoscopy while they are intubated for surgery. For example, all those patients with pulmonary secretions, recent chest infection, COPD, smokers etc 2. Bronchoscoping such patients for secretion control 3 may well improve their oxygenation during anaesthesia, and will greatly reduce the likelihood of their suffering postoperative lobar collapse—a common cause for ITU admission postoperatively. Obese patients will often benefit from having the position of the ETT checked using a fibrescope, especially if in Trendelenberg.

• BTS (2001). British Thoracic Society guidelines on diagnostic ﬂexible bronchoscopy. Thorax; 56 (Suppl I), i1–121. http://www.brit-thoracic.org.uk/clinical-information/bronchoscopy/ bronchoscopy-guidelines.aspx • Hawkins N (2000). Fibreoptic intubation. (Greenwich Medical Media Ltd, Lond.)

1Although it is common practice to use a size 8 mm ETT for females in ITU, I find 8.5 mm a better size with regard to fibreoptic bronchoscopy. Once an 8 mm ETT has been in place for more than about 24/hrs, even a small amount of tube secretions is often sufficient to make passing the regular (large) fibrescope difficult, sometimes requiring the ETT to be changed to 8.5 mm. 2If the ETT requires suctioning, then a quick bronchoscopy will probably be of greater perioperative benefit. 3Remember to send off a sputum or BAL sample for Gram stain, microscopy and culture.

78 CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

• Campos JH (2009). Update on tracheobronchial anatomy and flexible fiberoptic bronchoscopy in thoracic anesthesia. Current Opinion in Anaesthesiology; 22, 4–10. • Jolliet PH and Chevrolet JC (1992). Bronchoscopy in the intensive care unit. Intensive Care Medicine; 18, 160–169. • Mehta AC (Ed.) (2010). Interventional pneumonology [bronchoscopy] Clinics in Chest Medicine, 31 (March). (WB Saunders Company, London). For table of contents (TOC) see http://www.sciencedirect.com/science/journal/ 02725231 • Mehta AC (Ed.) (2001). Flexible bronchoscopy update. Clinics in Chest Medicine, 22 (June). (WB Saunders Company, London). • Oho K and Amemiya R (1984). Practical fiberoptic bronchoscopy. 2nd ed. Trans- lated by JP Barron. (Igaku-Shoin Medical Publishers, Inc., New York) pp. 218. ISBN 0-89640-103-0 • Slinger PD (1989). Fibreoptic bronchoptic positioning of double-lumen tubes. J. Cardiothoracic Anesthesia; 3, 486–496. (http://www.thoracic-anesthesia. com/) • Wang Ko-Pen, Mehta AC and Turner JF (2004). Flexible bronchoscopy. 2nd ed. (Blackwell Publishing, UK). [see the excellent cardio-thoracic anatomy diagrams in chapter 5, showing how the vessels are related to the bronchial tree (Applied anatomy of the airways) by Kavuru MS and Mehta AC (2004), pp. 36–38] • Watson CB (1987). Fibreoptic bronchoscopy in thoracic anaesthesia. In: Gothard JWW [Ed.], Thoracic anaesthesia. Clinical Anaesthesiology; 1 (March); pp. 33–60.

5.1 History

Although the Englishman John Tyndall described the optical properties of flexible glass fibres in 1870, it was not until 1957 that the first ‘gastro-fibrescope’ was developed by B. Hirschowitz in the USA. An improved version was subsequently developed in Japan by the Machida Endoscope Co. Ltd in 1962. In 1964 the Japanese physician Shigeto Ikeda, in collaboration with the Machida Endoscope Co. Ltd, started developing a fibreoptic bronchoscope which was eventually manufactured in 1967 (Ikeda et al. 1968; Ikeda 1974). Ikeda’s conference presentation of an early prototype in 1966 is remembered by Dr Ono as follows:

It was at this transitional period of decreasing pulmonary tuberculosis to increasing lung cancer that a flexible bronchofibrescope came to be recognized. The credit for the first to report on the subject must go to Dr Shigeto Ikeda. He demonstrated it with motion pictures . . . in Copenhagen in August 1966. Also, Dr Ikeda was first to publish CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

an article on the use of the ﬂexible bronchoﬁbrescope which appeared in the Journal of Japan Broncho-esophagological Society and Keio Journal of Medicine in 1968. Ono J (Foreword; In: Ikeda, 1974).

• Becker DH (2010). Bronchoscopy: the past, the present and the future. Clinics in Chest Medicine, 31 (March), 1–18. • Ikeda S (1974). Atlas of flexible bronchofiberscopy. (Igaku Shoin Ltd., Tokyo). [Chapter 1 describes the historical development of the flexible bronchoscope] • Ikeda S, Yani N and Ishikawa S (1968). Flexible bronchofiberscope. Keio J. Medicine; 17, p. 1. [First journal article on the use of the fibreoptic bronchoscope] • Shore JM and Lippman HN (1965). A flexible choledochoscope. Lancet; i, 1200.

5.2 Bronchoscopy simulator

There is a useful online simulator for demonstrating endobronchial anatomy on Peter Slinger’s thoracic anaesthesia website (http://www.thoracic-anesthesia.com/). You ﬁrst have to take a brief test on double-lumen tube placement, giving a username and password, after which you can access the simulator. Importantly, you are then free to log-in and use the simulator anytime thereafter. Unfortunately some of the video images in the test are poor and unclear, but the simulator is generally good value and quite realistic.

5.3 Carina

The position of the carina is surprisingly variable (see Section 4.5), and depends on body shape, size, posture, operation (e.g., laparoscopy). Factors which alter the position of the diaphragm generally move the carina in a similar direction. Consequently, one should have a low threshold for using the fibrescope to check the position of the tube—when in doubt—and especially in the various cases described in Section 4.5. The TEPID database predicts the distance to the carina in supine patients reasonably well (see Section 6.4.3). To measure the distance between the end of the ETT and the carina, first place the tip of the fibrescope on the carina and then grip the fibrescope at the ETT swivel-connector. Now, while maintaining the same grip on the fibrescope, slowly withdraw the fibrescope until the end of the ETT just comes into view. Now the distance between your grip on the fibrescope and the ETT swivel-connector is the same as the distance between the end of the ETT and the carina. CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

5.4 Left subcarina & beyond

Figures 5.1 and 5.2 show the anatomy as seen down the fibrescope by an anaesthetist positioned at the head end of a supine patient (without the camera attachment.4) The key features to note are (a) the orifices of the second-order bronchi either side of the left subcarina lie on a line running from top left to bottom right (see dashed line in Figure 5.1), (b) the first part of the left lower-lobe bronchus is characterised by the orifice of the bronchus to the apical segment of the left lower lobe at the 6–7 o’clock position, and (c) the orifice of the lingula bronchus (lower division of the left upper lobe bronchus) is the first division (on the RHS) of the left upper lobe bronchus (see Section 4.4 for nomenclature).

Figure 5.1: Left: The left subcarina viewed from the carina, constructed from a CT-scan (so-called ‘virtual bronchoscopy’), showing the typical orientation of the left upper and lower second-order bronchi when viewed from the head end in a supine patient. Copyright © RWD Nickalls & J James 2005 Right: Schematic of the left picture, showing how the left upper-lobe bronchus divides into the lingula bronchus (Li) and the left upper division bronchus (LUL). In addition we see the characteristic position of the oriﬁce of the apical bronchus (A) of the apical segment of the left lower lobe (LLL) just inside the entrance of the left lower-lobe bronchus, typically at the 6–7-o’clock position. Note the typical orientation (straight dashed line) of the second-order bronchi either side of the subcarina. The schematic shows the view associated with the closest safe approach of the end of the double-lumen tube (dashed circle) with respect to the left subcarina and second-order bronchi. Copyright © RWD Nickalls 2005

4See Section 5.6.3 CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

Figure 5.2: Top left: Left lung medial supine view. Top right: Supine view of left lower-lobe bronchus. Bottom: Close up view of the left supine hilum. Note that the lung is shown in the supine position being viewed medially (cf. Figure 4.6), and hence the orientation of the left subcarina here is consistent with the images in Figure 5.1. Since this view also has the same orientation as that seen down the bronchoscope (viewed from the head end), it makes the anatomy much easier to understand. For example, we can now see clearly how in the supine position the bronchus to the apical segment (yellow) of the left lower-lobe descends almost vertically down from the ﬁrst part of the lower lobe bronchus (see also Figure 5.1 opposite). (From Brock (1942–1944), with permission). CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

5.5 Right subcarina & beyond

Figure 5.3 shows the right upper lobe and the typical arrangement of the three bronchopulmonary segments.

Figure 5.3: Left: The RUL viewed from the right main bronchus in the supine position, showing the typical orientation of the three bronchopulmonary segments; apical (blue), posterior (red), anterior (green). Right: Lateral prone view—cf. Figures 4.5 and 5.4( From Brock (1942–1944), with permission).

Figure 5.4 shows the anatomy as seen down the bronchoscope by an anaesthetist positioned at the head end of a supine patient (without the camera attachment.5) While the entrance to the right upper lobe is straightforward to recognise, its exact distance from the carina is fairly variable. The part between the right upper lobe and the middle lobe bronchus is known as the lower part of the right main bronchus.6 The key bronchoscopic features to note are (a) the entrance to the right upper lobe, and the configuration of its immediate subdivisions,7 (b) the orifice of the bronchus to the apical 8 segment (yellow) of the lower lobe typically at the 5–6 o’clock position, and (c) the orifice of the middle lobe bronchus typically at the 12–2 o’clock position.

5See Section 5.6.3 6Historically known as the bronchus intermedius—see Section 4.4 for correct nomenclature. 7Typically three symmetrical sub-bronchi as shown in Figure 4.7—but quite variable. 8Sometimes known (incorrectly) as the superior segment—see Section 4.4. CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

Figure 5.4: Top left: Right lung medial supine view. Top right: Supine view of right lower lobe bronchus. Bottom: Close up view of the right supine hilum. Note that the lung in these views is shown in the supine position (cf. Figure 4.5). The oriﬁce of the bronchus to the apical segment (yellow) of the lower lobe is typically in the 5–6 o’clock position. The oriﬁce of the middle lobe bronchus is at the same level but in the 12–2 o’clock position. (From Brock (1942–1944), with permission). CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

5.6 Image orientation

A significant but seemingly neglected aspect of the fibreoptic bronchoscope (fibrescope) is the influence of the 3-D geometry of the combined set of optical fibres on the fidelity of the perceived orientation of the viewed image associated with (a) axial rotation, and (b) bending of the fibrescope. This is an interesting, if somewhat non-intuitive, feature of fibreoptics which has a significant bearing on the interpretation of the viewed images. Surprisingly, I have not as yet found any texts which discuss this. It is important to be aware of this aspect of fibreoptic geometry, since appreciation of position within the essentially fractal structure of the bronchial tree is largely a matter of orientation and knowledge of asymmetric anatomical features. In my experience axial rotation (Section 5.6.1) can cause gross distortion of image orientation, whereas that associated with bending (Section 5.6.2) is generally minimal in a clinical setting. To further complicate matters, these effects vary depending on whether the fibrescope is being used normally (monocular-mode) or with the camera attachment (camera-mode). We will address camera-mode at the end, but in the meantime unless specified, we will assume that we are dealing with normal monocular-mode.

5.6.1 Axial rotation Under normal circumstances (monocular-mode) when a fibrescope is rotated axially (and able to freely rotate throughout its length), the visual image remains fixed (on the retina)— providing the observer’s head is fixed—and hence the image does not rotate. However, if, during manual proximal axial rotation, the fibrescope is gripped distally (i.e., fails to rotate synchronously with the proximal end) then the observer (fixed) will see the image rotate with, and in the same sense as, the proximal end of the fibrescope. Consequently, I routinely use the following simple manoeuvre to determine whether a given image reflects the true orientation of the object, namely:- manually rotate the fibrescope (axially) back and forth slightly and observe whether the image rotates accordingly or not. If the image fails to rotate (i.e., the fibrescope is not gripped or restricted distally) we can be confident 9 that the image shows the true orientation of the object, in which case the observed orientation can be safely used to guide the observer regarding true location within the bronchial tree. If the image does rotate with the fibrescope (i.e., the fibrescope is gripped or restricted distally), then a situation of false orientation can be said to exist, and hence the orientation must be assumed to be false unless proven otherwise,10 in which case the user should not place any reliance on the perceived orientation of the image when determining location. In this case, only those anatomical landmarks having a known asymmetry can be relied upon for determining location within the bronchial tree.

9Because no rotation implies that the ﬁbrescope is not gripped, and therefore we know the view is ‘true’. 10In the same way that although a ‘stopped’ watch will occasionally be correct (twice a day if it is an analogue watch), in practice the time shown must be assumed to be false until proven otherwise. CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

For example, the left upper- and lower-lobe orifices are orientated either side of the left subcarina typically on a line running from top-left to bottom-right when viewed in a supine patient from the head end (see Figure 5.1). If the fibrescope is gripped sufficiently so that ‘false orientation’ exists, then the apparent orientation of the left subcarina will vary with the rotation of the fibrescope. Consequently, the anaesthetist may be misled by the perceived orientation unless the existence of ‘false orientation’ is checked for (see above) and recognised. If ‘false orientation’ is confirmed, then the anaesthetist will need to check for known asymmetries (e.g., the location of the bronchus to the apical segment of the left lower lobe) in order to confirm that the object in question is actually the left subcarina. Naturally, in the context of thoracic surgery, one must be alert to the posibility that local pathology may alter the expected orientation of structures.

5.6.2 Bending As the fibrescope passes further into the bronchial tree, it is necessarily bent in various directions. For example, in order to look at the left subcarina the fibrescope must pass down the trachea (inclined approximately 15 degrees below the horizontal) and then down the left main bronchus (deviated about 45 degrees towards the left). Bending the fibrescope successively through these two directions results in the tip of the fibrescope being rotated axially in a clockwise direction (compared with a straight fibrescope held horizontally in the direction of the trachea), resulting in a small ‘false’ anti-clockwise rotation of the image of the left subcarina. The magnitude of the image rotation is the product of the first angle multiplied by the sine of the second angle, and in this particular example would be a 11 barely noticeable 10 degree anticlockwise rotation, namely 15◦ sin45◦ = 10 6◦. This represents another interesting, if somewhat even more non-intuitive,× example· of orientation distortion arising from the 3-D geometry of the fibrescope. If you removed the left main bronchus, mediastinum and right lung so as to be able to look directly at the left subcarina in the supine position (see Figure 5.2) you would see the true orientation, as shown by a CAT scan (see Figure 5.1).

5.6.3 Camera-mode A camera attachment is often used with the ﬁbrescope for teaching purposes, and also to facilitate visualisation during percutaneous dilational tracheostomy. Hazard for the unwary: It is very important to appreciate that camera-mode introduces two signiﬁcant differences with respect to image orientation compared with monocular-mode, and hence the orientation must be assumed to be false unless proven otherwise. Firstly, the camera introduces a systematic and arbitrary image rotation—since

11Note that assigning a negative sign to the directions Lower and Left (and conversely)—when viewed monocularly from the head-end of a supine patient—associates anticlockwise with +ve, and clockwise with ve image rotation. Thus, in the above example of the left subcarina, we have ( 15◦) (sin 45◦) = +10 6◦, i.e.,− there is anticlockwise image rotation. − × − · CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

it can be attached to the eye-piece in any position. Second, the camera reverses the axial rotation effect on the screen image compared to monocular-mode. For orientation to be correct during camera-mode, the camera position relative to the bronchoscope needs to be ‘calibrated’ against reality; i.e., when attaching the camera one must first rotate it relative to the bronchoscope in order to align the screen image appropriately with the patient before locking it in position. For example, when using camera-mode while performing a tracheostomy, we first ‘calibrate’ by rotating the camera relative to the bronchoscope until anterior movement on the trachea corresponds with vertical motion on the monitor/screen. Failure to calibrate accurately can result in a true anterior indentation of the trachea appearing instead to be from one side. As before, there are two scenarios to consider: (1) fibrescope free to rotate, and (2) fibrescope gripped distally. 1. Fibrescope free to rotate: When the fibrescope-camera unit is rotated axially the screen image rotates in the opposite direction, since the image mapping from the camera to the monitor screen is fixed [in monocular-mode, assuming the viewer’s head is fixed, there is no such rotation] This is typically the situation when surgeons use the camera attachment on a fibrescope passed down the lumen of a rigid bronchoscope, since in this setting the fibrescope is always free to rotate as there is nothing to grip it. 2. Fibrescope gripped: If the fibrescope is gripped distally while the proximal end is manually rotated, then the screen image does not rotate. [in monocular-mode there is rotation in the same direction] This situation often arises when the fibrescope is passed down an endotracheal tube, since the fibrescope is usually gripped to some extent by the rubber air-tight seal at the entrance of the endotracheal tube.

5.7 Anaesthesia for bronchoscopy

5.7.1 Short duration Intermittent boluses of propofol, suxamethonium and remifentanil 12 increments.

5.7.2 Long duration Propofol TIVA is particularly useful for prolonged bronchoscopy (e.g., for reboring tracheal tumours, multiple biopsies, insertion of stents.13) With the Alaris pump use the Schnider

12See Section 8.4. 13e.g., Montgomery tubes (see Section 3.9) CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

algorithm for propofol TCI,14 and the Minto algorithm for remifentanil TCI (Absalom and Struys 2007), since both of these use the Lean Body Mass (LBM) calculated from the entered total body weight and height. An arterial line is worth considering, especially with frail patients and difﬁcult cases. An induction plasma concentration (Cp) target for adults of 7 µg/ml followed (once the rigid bronchoscope has been inserted) by a maintenance target of about 5–6 µg/ml plus a narcotic (e.g., remifentanil) generally works well (reduce these somewhat if the patient is elderly and/or frail). Consider an initial remifentanil bolus of about 100 µg (for a 70 kg patient) followed by about 250 µg/hr. Sometimes it is more convenient to give the remifentanil as intermittent boluses rather than run a second pump. A long acting relaxant is generally best, but sometimes it is worth starting with intermittent suxamethonium and converting later if necessary. Historically, a suxamethonium infusion would often have been used in this setting; it can still be useful on occasions. The technique for adults is to use 500 mg in 500 mls saline—run at about 3 mg/min (a normal blood giving-set has 25 drops 1 ml, so 3 mg/min is 75 drops/min). Avoid using the infusion for more than about 30 mins≡ (in order to keep the total suxamethonium dose less than about 3 kg), and always use a nerve stimulator to help minimise the total dose and avoid a type-II× block (always take care to label the infusion very clearly).

• Absalom AR and Struys MMRF (2007). Overview of target controlled infusions and total intravenous anaesthesia. 108 pp. (Academia Press, Ghent, Belgium; http://www.academiapress.be/) ISBN 978-90-382-11077 [excellent small book sponsored by Cardinal Health, Basingstoke, Hampshire, UK.] • Aly EE (2002). Anaesthesia for bronchoscopy. Anaesthesia; 57, 93–94. (letter and reply) [using propofol and remifentanil] • Gillbe C and Hillier J (2005) Anaesthesia for bronchoscopy, tracheal and airway surgery. Anaesthesia and Intensive Care Medicine; 6, 422–425. • McKeage K and Perry CM (2003). Propofol. A review of its use in intensive care sedation of adults. CNS Drugs; 17, 235–272. [excellent] • Prakash N et al. (2001). Effects of remifentanil on haemodynamic stability during anaesthesia for rigid bronchoscopy. Anaesthesia; 56, 576–580. [see Aly 2002] • Purugganan RV (2008). Intravenous anesthesia for thoracic procedures. Current Opinion in Anaesthesiology; 21, 1-7.

14Note that there is a potential problem when using TCI with lean body mass (LBM) algorithms in obese patients. For any given height the calculated LBM rises to a maximum and then falls as weight increases, and so in obese patients you need to use that body weight which generates the maximum LBM—see Absalom and Struys (2007), pp. 30–33 for details and useful charts. CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

• Russell D (2002). Practical aspects of target-controlled infusion. Anaesthesia Rounds; (TMG Healthcare Communications Ltd., 62 Stert Street, Abingdon, Ox- fordshire, UK). 27 pp. + CD ROM. [Sponsored by AstraZenica]

5.7.3 Local anaesthesia & sedation • Conacher ID and Curran E (2004). Local anaesthesia and sedation for rigid bronchoscopy for emergency relief of central airway obstruction. Anaesthesia; 59, 290–292. [describes use of oral and trans-cricothyroid lignocaine, propofol and midazolam]

5.7.4 Venturi jet ventilation The ﬁrst practical venturi jet system for ventilating down a rigid bronchoscope was developed in 1967 by Richard Douglas Sanders (Buckley 1992; Sanders 1967; Aikens and Bancroft 1977; Maltby 2002). See article by Baraka et al. (2001) for details of its use for ventilating down an endotracheal tube (above a tracheal stenosis). Robinson (1997) describes the use of a Hunsaker jet ventilation tube. The potential dangers (e.g., pneumothorax) associated with jet ventilation via exchange catheters is addressed by Benumof (1991). See also Section 3.10 on difﬁcult airways.

5.8 References

• Bronchoscopy Atlas: html://www.int-med.uiowa.edu/research/tlirp/ BronchoscopyAtlas/Home.html • Baraka AS, Siddik SS, Taha SK, Jalbout MI and Massouh FM (2001). Low frequency jet ventilation for stent insertion in a patient with tracheal stenosis. Can. J. Anaesth.; 48, 701–704. • Buckley JJ (1992). Richard Douglas Sanders, MD. Anesthesiologist, inventor, painter (1906–1977). In: Fink BR, Morris LE, Stephen CR (Eds.) The history of anesthesia third international symposium. (Wood Library-Museum of Anesthesiol- ogy). p. 72–77. [cited from Maltby 2002] • Benumof JL (1999). Airway exchange catheter: simple concept, potentially great danger [editorial] Anesthesiology; 91, 342–344. • Carden E, Burns WW, McDevitt NB and Carson T (1973). A comparison of venturi and side-arm ventilation on anesthesia for bronchoscopy. Can. Anaesth. Soc. J.; 20, 569–574. • Carden E and Schwesinger WB (1973). The use of nitrous oxide during ventilation with the open bronchoscope. Anesthesiology; 39, 551–555. CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

• Carlon GC, Ray C, Grifﬁn et al. (1983). Tidal volume and airway pressure on high frequency jet ventilation. Crit. Care Med.; 11, 83–86. • Cromwell SB, Hirshman CA, McCullough RE and Cohen PJ (1975). Simpliﬁed delivery of volatile anesthetics for bronchoscopy. Anesthesiology; 43, 377–379. • Maltby RJ (Ed.) (2002). Sanders injector: Richard Douglas Sanders (1906–1977). In: Notable names in anaesthesia. (Royal Society of Medicine Press, London). p. 187–189. [ISBN 1853-155-128]. • Miyasaka K, Sloan IA, and Froese AB (1980). An evaluation of the jet injector (Sanders) technique for bronchoscopy in pediatric patients. Can. Anaesth. Soc. J.; 27, 117–124. • O’Sullivan TJ and Healy GB (1985). Complications of venturi jet ventilation during microlaryngeal surgery. Arch. Otolaryngol.; 111, 127–131. • Patel C and Diba A (2004). Measuring tracheal airway pressures during transtracheal jet ventilation: an observational study. Anaesthesia; 59, 248–251. [carinal pressure changes were small; approximately 13 mm Hg only] • Robinson RJ (1997). One-lung ventilation for thoracotomy using a Hunsaker jet ventilation tube. Anesthesiology; 87, 1572–1574. • Sanders RD (1967). Two ventilating attachments for bronchoscopes. Delaware Med. J.; 39, p. 170–176. • Spoerel WE and Grant PA (1971). Ventilation during bronchoscopy. Can. Anaesth. Soc. J.; 18, 178–188.

5.8.1 Complications • Suratt PM, Smiddy JF and Gruber B (1976). Death and complications associated with ﬁbreoptic bronchoscopy. Chest; 64, 747–751.

5.8.2 Fibreoptic intubation • Hawkins N (2000). Fibreoptic intubation. (Greenwich Medical Media Ltd, Lond.) • Murphy PA (1967). Fibre-optic endoscope used for nasal intubation. Anaesthesia; 22, 489. • Taylor PA and Towey RM (1972). The bronchoﬁbrescope as an aid to endotracheal intubation. Br. J. Anaesth.; 44, 611. • Mason RA (1992). Learning ﬁbreoptic intubation: fundamental problems. Anaes- thesia; 47, 729. CHAPTER 5. FIBREOPTIC BRONCHOSCOPY RWD Nickalls 

• Mason RA (1998). Education and training in airway management. Br. J. Anaesth.; 81, 305–307. • Morris IR (1994). Fibreoptic intubation. Canadian J. of Anaesthesia; 41, 996.

• Ovassapian A (1996). Fibreoptic endoscopy and the difﬁcult airway. 2nd ed. (Lipincott-Raven, Philadelphia, USA). 6 Tubes and bronchus blockers

Two recent articles are worth noting.

• Brodsky JB (2009). Lung separation and the difﬁcult airway. Br. J. Anaesth.; 103 (Suppl. I): i66–i75. [137 refs] • Campos JH (2009). Update on selective lobar blockade during pulmonary resections. Current Opinion in Anaesthesiology; 22, pp. 18–22.

6.1 The Univent tube, 1984

The Univent tube is a combined blocker and ETT, and made in Japan. The literature suggests that they are not as good as a well positioned double-lumen tube, but may well be useful in unusual situations.

• Campos JH, Reasoner DK and Moyers JR (1996). Comparison of a modiﬁed double- lumen endotracheal tube with a single-lumen tube with enclosed bronchial blocker [Univent tube]. Anesthesia and Analgesia; 83, 1268–1272. [conclusion:- DLT better than Univent tube (more malpositions with the Univent tube)] • Hultgren BL, Krishna PR and Kamaya H (1986). A new tube for one lung ventilation: experience with the Univent Tube. Anesthesiology; 65(3A), A481.

• Inoue M, Shohtsu A, Ogawa J et al. (1984). Endotracheal tube with movable blocker to prevent aspiration of intratracheal bleeding. Annals of Thoracic Surgery; 37, 497–499. • Kamaya H and Krishna PR (1985). New endotracheal tube (Univent tube) for selective blockade of one lung. Anesthesiology; 63, 342–343.

92 CHAPTER 6. TUBES AND BRONCHUS BLOCKERS RWD Nickalls 

6.2 The Hunsaker jet ventilation tube

• Robinson RJ (1997). One-lung ventilation for thoracotomy using a Hunsaker jet ventilation tube. Anesthesiology; 87, 1572–1574.

6.3 Bronchus blockers

Although Fogarty catheters have been used as bronchial blockers in adults (Ginsberg 1981) and in children (Tan and Tan-Kendrick 2002), special bronchus-blocker kits are now available. The one we generally use at the City Hospital is the Arndt endobronchial blocker set manufactured by Cook.1 This consists of a 9 Fr-gauge bronchus blocker (78 cm) having a blue balloon at the end, together with a special tube-adaptor having three channels one each for anaesthesia gases, the bronchus blocker, and the fibrescope. A new form of blocker has recently been described by Mungroop et al. (2010). The Arndt bronchus blocker has a small loop at its tip, and is guided into position by first sliding it along the fibrescope, and then positioning it under direct vision. The art seems to be to place the tip of the fibrescope just inside the required main bronchus (i.e., not right down to the subcarina) 2 and then push the blocker down. Once the blocker falls off the end of the fibrescope it will be visible and can then be manipulated into position under direct vision. It is important to make sure that both the end loop and balloon remain within the main bronchus (i.e., do not migrate further down into a second-order bronchus where they might stray into surgical territory). Note that two slightly different shaped balloons are supplied; one is long and thin (for the left main bronchus), and the other is fatter in the middle (for the right main bronchus). The length of each is about 2–2 5 cm (i.e., about half the length of the left main bronchus in an average adult man). ·

• Campos JH (2003). An update on bronchial blockers during lung separation techniques in adults. Anesthesia and Analgesia; 97, 1266–1274. • Culp WC and Kinsky MP (2004). Sequential one-lung isolation using a double Arndt bronchial blocker technique. Anesthesia & Analgesia; 99, 945–946.

• Ginsberg RJ (1981). New technique for one-lung anaesthesia using an endobronchial blocker. Journal of Thoracic and Cardiovascular Surgery; 82, 542–544. • Mungroop HE, Wai PTY, Morei MN, Loef BG and Epema AH (2010). Lung isolation with a new Y-shaped endobronchial blocking device—the EZ-blocker. Br. J. Anaesth.; 104, 119–120.

1William Cook Europe A/S, Sandet 6, DK-4632 Bjaeverskov, Denmark; http://www.cookmedical.com/cc/products.do/ 2Described to me by Dr K Alagesan. CHAPTER 6. TUBES AND BRONCHUS BLOCKERS RWD Nickalls 

• Tan GM and Tan-Kendrick APA (2002). Bronchial diameters in children—use of the Fogarty catheter for lung isolation in children. Anaesthesia & Intensive Care; 30, 615–618. • Uzuki M, Kanaya N, Mizuguchi A et al. (2003). One-lung ventilation using a new bronchial blocker in a patient with tracheostomy stoma. Anesthesia and Analgesia; 96, 1538–1539.

6.4 Double-lumen tubes

Several modern well engineered versions are available (e.g., Mallinckrodt, Portex, Rusch).¨ While none is perfect—each has its own advantages and disadvantages—all are certainly far better than the old red-rubber versions. The Mallinckrodt BronchoCath would seem to be the best of those currently available in the UK as regards ease of placement, bronchoscopic access, and having good robust connectors. Both Portex and Rusch¨ also make double- lumen tracheostomy tubes (see Section 3.2).

6.4.1 History Initial progress in thoracic anaesthesia seems to have been held up largely by trying to figure out how to overcome the problems associated with pneumothorax in a spontaneously breathing patient. Although physiologists have been ventilating the lungs of animals using bellows via a tube in the trachea for centuries,3 there seems to have been a mental-block about this in the medical community until relatively recently. The double-lumen tube was originally developed by the physiologist Henry Head (1889). He was interested in separating gas entering and leaving each of the two lungs in animals. His tube was widely used for determining differential lung function well before it was used in thoracic anaesthesia (Comroe 1977, p. 15). In 1949 Carlens (1908–1990) designed a double-lumen endobronchial tube for use in broncho-spirometry (Carlens 1949), and subsequently for one-lung anaesthesia (Bjork¨ and Carlens 1950). A series of different modifications by Bryce-Smith 4 (1959), Bryce-Smith and Salt (1960), White (1960a) and Robertshaw (1962) followed. Note that the routine use of one-lung ventilation for lung resection was first advocated only in 1957 (see Slinger 1990).

3The physicist Robert Hooke showed that a dog could be kept alive indefinitely by IPPV via the trachea using a set of bellows (Hooke, 1666). Importantly, he also indicated in this paper that after making numerous holes in the lungs, the dog could be maintained just as easily using a continuous through flow of air. Hence he proved that, contrary to contemporary thinking, the physical movement of the lungs did not of itself benefit an animal other than by simply ensuring the necessary movement of air in and out of the lungs, and that the lungs were simply a device for oxygenating the blood flowing through them. Note that the book De Motu Cordis by William Harvey (1578–1657) describing the circulation of blood through the lungs was published in 1632. 4Anaesthetist Roger Bryce-Smith (1918–2006) died in March 2006. See his obituary in British Medical Journal (2006); 332, 1277 (May 27). CHAPTER 6. TUBES AND BRONCHUS BLOCKERS RWD Nickalls 

See also articles on the general history of endobronchial anaesthesia (White 1960b), and on the history of the various tubes (Pappin 1979) and instruments (Hillard and Thompson 1963). See also the cardiothoracic section in Rushman, Davies and Atkinson (1996) for various historical references.

The Robertshaw tube (1962) A red-rubber tube with D-shaped lumina which has a lower resistance to gas ﬂow than either the Carlens or White double-lumen tubes (Robertshaw 1962). Angular deviation of the endobronchial part from the midline is 20 ◦ on the right and 45 ◦ on the left. Three sizes only; large, medium, small.

References • Bjork¨ VO and Carlens E (1950). The prevention of spread during pulmonary resection by the use of a double-lumen catheter. Journal of Thoracic Surgery; 20, 151 [from Pappin 1979] • Brodsky JB (2005). The evolution of thoracic anesthesia. Thoracic Surgery Clinics; 15, 1–10. • Bryce-Smith R (1959). A double-lumen endobronchial tube. Br. J. Anaesth.; 31, 274 [from Pappin 1979] • Bryce-Smith R and Salt R (1960). A right-sided double-lumen tube. Br. J. Anaesth.; 32, 230 [from Pappin 1979] • Carlens E (1949). New ﬂexible double-lumen catheter for broncho-spirometry. Journal of Thoracic Surgery; 18, 742–746 [from Maltby 2002] • Comroe JH (1977). Retrospectroscope: insights into medical discovery. (Von Gehr Press, Menlo Park, California, USA). • Hammond and Wright (1984). Comparison of the resistances of double-lumen endo-bronchial tubes. Br. J. Anaesth.; 56, 299–301.

• Head H (1889). On the regulation of respiration. Journal of Physiology, 10, 1–70. • Hillard EK and Thompson PW (1963). Instruments used in thoracic anaesthesia. In: Thoracic Anaesthesia (2nd edn) (Ed. by WW Mushin), p. 267. (Blackwell Scientiﬁc Publications, Oxford, UK). [from Pappin 1979]

• Hooke R (1666). An account of an experiment made by Mr. Hook, of preserv- ing animals alive by blowing through their lungs with bellows. Philosophical Transactions of the Royal Society; 1665–1678; vol 2, vol 2 1666-1667. [http: //www.journals.royalsoc.ac.uk/] CHAPTER 6. TUBES AND BRONCHUS BLOCKERS RWD Nickalls 

• Maltby RJ (Ed.) (2002). Carlens catheter: Eric Carlens (1908–1990). In: Notable names in anaesthesia. (Royal Society of Medicine Press, London). [ISBN 1853-155- 128]. • Pappin JC (1979). The current practice of endobronchial intubation Anaesthesia; 34, 57–64. [includes good history of double-lumen tubes] • Robertshaw FL (1962). Low resistance double-lumen endo-bronchial tube. Br. J. Anaesth.; 34, 576–579. • Rushman GB, Davies NJH and Atkinson RS (1996). A short history of anaesthesia: the ﬁrst 150 years. (Butterworth-Heinemann, Oxford, UK) ISBN 0-7506-3066-3. • Slinger PD (1990). Anaesthesia for lung resection. Can. J. Anaesth.; 37, Sxv–Sxxiv. [106 refs; part of the refresher course outline] • White GMJ (1960a). A new double-lumen tube. Br. J. Anaesth.; 32, 232.

• White GMJ (1960b). Evolution of endotracheal and endobronchial intubation. Br. J. Anaesth.; 32, 325.

6.4.2 The BronchoCath [Mallinckrodt Medical (UK) Ltd, 11 North Portway Close, Round Spinney, Northampton, NN3-8RQ, UK.] The BronchoCath (Mallinckrodt Medical, 1983) is a disposable polyvinylchloride (PVC) low resistance double-lumen endobronchial tube. Angular deviation of the endobronchial part from the midline is 15◦ on the right and 30◦ on the left. Five sizes for the left, four sizes for the right (see Table 6.1).

Table 6.1: BronchoCath Body of tube L endobronchial OD mm OD mm 41 Fr 14–15 10 6 39 Fr 13–14 10·1 37 Fr 13–14 10·0 35 Fr 12–13 9 ·5 32 Fr — —· 28 Fr — —

The Mallinckrodt bronchial cuff was originally clear and transparent (just like the tracheal cuff). It was subsequently changed to the current blue colour following complaints that the cuff was difﬁcult to visualise during ﬁbreoptic bronchoscopy. CHAPTER 6. TUBES AND BRONCHUS BLOCKERS RWD Nickalls 

Table 6.2: BronchoCath Size Length to teeth Large 41 Fr (L/R) 30 1 cm Medium 39 Fr (L/R) 28 ± 1 cm Intermediate 37 Fr (L/R) 27 ± 1 cm Small 35 Fr (L/R) 26 ± 1 cm V. Small 32 Fr (L only) ±— Child 28 Fr (L only) —

Table 6.3: This Table is from Brodsky et al. 1996 Measured tracheal Predicted L Size width on chest x-ray bronchus width 18 mm 12 2 mm 41 Fr ≥ 16 mm ≥ 10·9 mm 39 Fr ≥ 15 mm ≥ 10·2 mm 37 Fr ≥ 14 mm ≥ 9 ·5 mm 35 Fr ≤ ≤ ·

Although Mallinckrodt recently made some improvements to their left-sided tube, in my view these tubes still have serious design faults; for example (a) the left endobronchial tip is bevelled medially (should be bevelled slightly laterally to face the subcarina), (b) the right endobronchial tube should have a much larger right upper-lobe oriﬁce.

• Brodsky JB and Macario A (1995). Modiﬁed BronchoCath double-lumen tube. J. Cardiothorac. Vasc. Anesth.; 9, 784–785. [see also editorial pp. 117–118]

6.4.3 The tube database (TEPID) 5 Several studies have tried to correlate both tube size and depth of tube insertion with a single body parameter (e.g., height, weight or BMI), but none has proved particularly useful (see references below). This suggests that using only a single parameter is probably not a useful approach—not unexpected since tube distance from the teeth is markedly inﬂuenced by both diaphragm position (& hence with the degree of abdominal obesity) and height. Consequently my TEPID database uses three parameters (height, weight and gender), and gives quite accurate predictions (560+ patients in the database). The TEPID database of double-lumen tubes (DLT) can be useful for predicting both tube size and length for a given patient. For example, the predicted double-lumen tube lengths for an average supine male and female are given in Table 6.4.

5Tube and EPIdural Database (TEPID). This is a collection of thoracic epidural and tube data accumulated over many years. It is freely available from http://www.nickalls.org/dick/xenon/rwdnXenon.html CHAPTER 6. TUBES AND BRONCHUS BLOCKERS RWD Nickalls 

The TEPID program also gives the position of the DLT’s tracheal orifice, since this can be used to estimate the likely carina position (by adding approximately 1 5 cm, as the tracheal orifice of the double-lumen tube is typically 1–2 finger-breadths 6 from· the carina)

Table 6.4: TEPID data for length of double-lumen tube and tracheal oriﬁce position (cm) in an average supine male and female. In the UK the average male and female heights are approximately 5ft 9in (176 cms) and 5ft 4in (164 cms) respectively. See text regarding the value of the tracheal oriﬁce measurement. The results are given as: mean[range](n)

average male average female wt 76 7 5 kg wt 67 7 5 kg ± · ± · ht 176 7 5 cm ht 165 7 5 cm ± · ± · 41L 30 [27 5–32] (n=56) — · 39L 29 (n=1) 28 1 [26–30] (n=15) · 37L — 27 3 [26–29] (n=10) · 35L — 27 1 [26 5–28] (n=8) · · 41R 29 1 [28–30] (n=6) — · 39R 28 [27 5–29 5] (n=4) — · · 37R — 26 6 [25–29] (n=4) · 35R — 25 7 [25–27] (n=4) · tracheal oriﬁce 24 1 [21–26 5] (n=67) 21 5 [18 7–24] (n=41) · · · · The TEPID database, together with a Perl program, is freely available. After entering the patient’s height/weight/gender the program displays the relevant tube sizes and lengths (single and double-lumen).

References • Bahk J-H (1999). Prediction of double-lumen tracheal tube depth. J. Cardiothoracic Vasc. Anesth.; 13, 370–371.

• Benumof JL, Partridge BL, Salvatierra C and Keating J (1987). Margin of safety in positioning modern double-lumen endotracheal tubes. Anesthesiology; 67, 729–738. • Benumof JL (1988). Improving the design and function of double-lumen tubes. J. Cardiothorac. Vasc. Anesth.; 2, 729–733.

6Measured using a ﬁbrescope. CHAPTER 6. TUBES AND BRONCHUS BLOCKERS RWD Nickalls 

• Brodsky JB, Benumof JL and Ehrenwerth J et al. (1991). Depth of placement of double-lumen endobronchial tubes. Anesthesia and Analgesia; 73, 570–572. • Brodsky JB, Macario A and Mark JBD (1996). Tracheal diameter predicts double- lumen tube size: a method for selecting left double-lumen tubes. Anesthesia and Analgesia; 82, 861–864. • Dyer RA, Heijke SAM, Russell WJ, Bloch MB and James MFM (2000). Can insertion length for a double-lumen endobronchial tube be predicted? Anaesthesia and Intensive Care; 28, 666–668. [they compared (separately) height, weight, and the external surface distance (sternal-angle to ear-lobe via mouth) and found no useful correlation] • Hannallah MS, Benumof JL and Ruttiman UE (1995). The relationship between left mainstem bronchial diameter and patient size. J. Cardiothorac. Vasc. Anesth.; 9, 119–121. [see also editorial pp. 117–118; and article pp. 784–785]

• Joseph JE and Merendino KA (1957). The dimensional interrelationships of the major components of the human tracheobronchial tree. Surg. Gynecol. Obstet.; 105, 210–214. • Kato H, Suzuki A, Nakajima Y, Makino H, Sanjo Y, Nakai T, Shiraishi Y, Katoh T and Sato S (2009). A visual stethoscope to detect the position of the tracheal tube. Anesthesia and Analgesia; 109, 1836–1842.

• Slinger P (1995). Choosing the appropriate double-lumen tube; a glimmer of science comes to a dark art [editorial]. J. Cardiothorac. Vasc. Anesth.; 9, 117–118. [see also article on pp. 784–5]

• Slinger PD (2007). Lung isolation review. (http://www.thoracic-anesthesia. com/) • Yasumoto M, Higa K, Nitahara K, Shono S and Hamada T (2006). Optimal depth of insertion of left-sided double-lumen endobronchial tubes cannot be predicted from body height in below average-sized adult patients. European Journal of Anaesthesi- ology, 23, 42–44. [Japanese subjects of height 155 cm] ≤ 7 One-lung anaesthesia

E now focus on the practical details of positioning double-lumen tubes and the subsequent management of one-lung anaesthesia. The core skills are W (a) knowledge of the relevant anatomy, (b) some facility with the ﬁbrescope, and (c) a clear idea of what deﬁnes the ‘optimum’ position of the tube or blocker. For anaesthetic details regarding the standard range of thoracic operations/procedures see the overviews by Sanders (2006) and by Pearce & Gould (2005). Thoracic anaesthesia was the subject of an excellent recent issue of Anesthesiology Clinics (Slinger 2008). Preoperatively it is important to look at both the chest X-ray and CT-scan for potential problems not only with the operative side, but also with the dependent side and the trachea— for example, always check for a tracheal bronchus (see Ho et al., 2004). Listen to the chest to identify, among other things, any silent areas; after intubation such areas might otherwise mistakenly suggest tube malposition. In particular, note whether the upper lobes sound clear or not. Always use a CVP line for a thoracotomy.

7.1 Right double-lumen tube

Owing to the hazard of obstructing the right upper-lobe bronchus, relatively few right-sided tubes are used—probably only when a left-sided tube or bronchus blocker cannot be used (e.g., a sleeve resection of the left main bronchus).

7.2 Left double-lumen tube

For most left-lung surgery and all other thoracic surgery it is possible to use a left-sided tube or a bronchus blocker. However, when planning to use a left-sided tube or blocker for left lung surgery, it is a good idea to discuss this with the surgeons, just in case they are

100 CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

expecting a right-sided tube to be used. For example, they might anticipate having to do a sleeve resection for which you may not be able to use a left-sided tube. Since a left sided tube is used for both left and right thoracic surgery the strategy while on one-lung varies slightly depending on whether the endobronchial part of the tube is in the top lung (operative side) or the bottom lung (dependent side). The position of the patient (supine or lateral) also influences the strategy. Top-side (left endobronchial tube): In this case the primary danger is that the bronchial cuff may migrate back into the trachea and obstruct ventilation to the bottom lung. Conse- quently the strategy when on one-lung is to try and keep the bronchial cuff well below the carina, and not to worry unduly if the tip of the tube gets fairly close to the left subcarina. If when on one-lung, ventilation suddenly becomes obstructed, then this is almost always because the bronchial cuff is obstructing the bottom lung, and so the solution is (a) deflate the bronchial cuff temporarily, (b) push the tube further down the left main bronchus, (c) re-inflate the cuff, and finally (d) check the cuff position with a fibrescope. While you are on one-lung it is of no matter if the tip of the tube now obstructs the left upper lobe—the tube can be pulled back as necessary when returning to two-lungs, or when the surgeon needs to staple a lobar bronchus. Note that once the patient is in the lateral position, then the bulk of the cardiac output is going to the bottom lung, and so inadvertently obstructing the upper-lobe prior to going on to one-lung is not too problematic—the top lung will need to be collapsed anyway once the surgeons open the chest. However, this is not the case while the patient is supine (e.g., in the anaesthetic room) and significant desaturation may occur if the tube is pushed too far down at this stage. Bottom-side (left endobronchial tube): In this case the primary danger is that the tube may migrate further down and obstruct ventilation to the left upper lobe. Consequently the strategy when on one-lung is to try and keep the bronchial cuff close to the carina. Sometimes the endobronchial part of the tube is slightly too long for the patient, such that the tip is dangerously close to the left subcarina even when the cuff is at the carina, in which case a smaller tube is necessary.

7.3 Placing double-lumen tubes

Is there an optimum method for placing a given double-lumen tube? If by ‘optimum’ we mean the most efﬁcient sequence in the sense that information arising from each manoeuvre builds logically on previous manoeuvres, then the answer would seem to be ‘yes’. Prior to intubation it is important to exclude a supernumerary or displaced ‘tracheal’ bronchus (see Section 4.7) during bronchoscopy 1. Once intubated, it makes sense to start bronchoscopy with the tracheal side (view the carina via the tracheal lumen),

1Typically this is performed by the surgeons; it is important to (a) check for a tracheal bronchus, (b) check the position of the right upper lobe bronchus, and (c) suction any secretions, particularly in the ‘bottom’ lung. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

and then progress to the endobronchial side, since information gathered by looking at the tracheal side influences how one interprets findings on the endobronchial side. An optimum sequence for positioning a double-lumen tube would seem to be something along the following lines. • Listen to the chest preoperatively. • Bronchoscopy (to detect a tracheal bronchus, visualise the position of the RUL orifice and configuration of its bronchopulmonary segments, suction secretions). • Insert double-lumen tube. • Stethoscope check (to detect upper-lobe obstruction by the tube), • Bronchoscope check: – tracheal side first (to see if the tube is down the correct side, and if there is any bronchial cuff above the carina). – bronchial side second (fine-tune position of the end of the tube). – tracheal side again (check and fine-tune position of bronchial cuff). Note that numerous studies have shown that double-lumen tubes are rarely optimumly positioned without bronchoscopic fine tuning. It is useful to consider the process of placing a double-lumen tube in several stages as follows: (a) preparation, (b) intubation, (c) stethoscope check, (d) bronchoscopy check, (e) final volume and pressure check, (g) turning the patient laterally. We now consider these in order.

7.3.1 Preparation Consider a ‘secretion drying’ premed (e.g., hyoscine) Hyoscine hydrobromide 2 (0 2–0 4 mg IM 1 hour preop). This greatly helps visualisation· · of the bronchial anatomy, and facilitates double-lumen tube placement. I therefore routinely use a hyoscine premed when I intend to place either a right-sided double-lumen tube or a bronchial blocker, as in these cases it helps to have particularly good viewing conditions since correct placement is sometimes not straight-forward. Getting the timing/dose of hyoscine right is quite important, since the action of hyoscine rarely lasts longer than about 90 mins in my experience.3 The doses I use are: average adult female (0 2–0 3 mg IM); average adult male (0 3–0 4 mg IM). · · · · 2Hyoscine hydrobromide (ampoules of 0 4 mg in 1 ml) Hyoscine is an anti-muscarinic agent; slightly sedating; and sometimes results in a slowish heart rate.· Important to use the full name on the prescription form to avoid possible confusion with Buscopan (hyoscine butylbromide; 20 mg in 2 mls.) 3It may therefore be better to use a longer acting agent like glycopyrollate instead, but I have not used it in this setting. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

Check the tubes, cuffs and suction catheters • Double-lumen tubes. Make sure you are familiar with the particular variety of double-lumen tube to be used, and that all the appropriate sizes are available. Make sure the correct connectors are available and that they all fit together. Check that the pilot balloons connect to the correct cuffs (see Nystrom 2003) and that the cuffs are intact; tracheal cuff (approx. 8 mls); bronchial cuff (approx. 3–4 mls). • Check the tube accommodates the ‘intubating’ fibrescope. If you are likely to need the ‘small’ double-lumen tube (35 Fr), then check that the fibrescope will pass through the tube. The Mallinckrodt BronchoCath sizes 41–37 Fr will always accept the 4 5 mm diam intubating fibrescope. However, sometimes the 35 Fr (‘small’) tube will· not accept the 4 5 mm fibrescope, so it is as well to check this before (i.e., find a 35 Fr which will accept· the fibresope). As regards lubrication, consider using Xylocaine spray as this seems to be much better than KY-jelly.

• Check the suction catheters are long enough (165 cms) The suction catheters should be about 5 cm longer than the double-lumen tube.

Consider starting with a single-lumen tube In potentially difﬁcult patients, and those likely to be in the anaesthetic room for a long time (e.g., oesophagectomy and other major cases), consider starting with a single-lumen tube, and placing the double-lumen tube as the ﬁnal anaesthetic-room procedure once all the lines are in. This has the advantage of allowing you to place the CVP, arterial line, NG-tube, bladder catheter etc. without worrying whether the double-lumen tube may have moved in the meantime, possibly resulting in the upper-lobe becoming obstructed (see Section 7.3.3). I therefore routinely adopt this approach in all cases needing a CVP line.

Anticipate the insertion distance of the double-lumen tube The TEPID database of tubes is useful for predicting both tube size and length for a given patient (see Section 6.4.3). In general the required size for an average male and female is 41 Fr and 39 Fr respectively. The distances are roughly as follows: 41 Fr (30–31 cm), 39 Fr (29 cm), 37 Fr (27–28 cm), 35 Fr (25–26 cm). A rough rule for the number of centimetres is the French gauge minus 10.

7.3.2 Intubation Apply gel lubrication to the tracheal cuff as it reduces leakage past the cuff (Sanjay et al. 2006). Use the stylette to give a suitable bend on the endobronchial part of the tube, and insert with the curve facing upwards. Once the bronchial cuff is through the cords rotate CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

the tube back into its anatomical position, and push gently into position. Since the trachea has only a thin layer of muscle posteriorly, it is easily perforated. If there is any resistance then consider trying a smaller tube. Both cuffs are extremely delicate and are easily torn. Consequently take great care not to let the cuffs touch the teeth; consider using a protective gauze/drape if necessary. Always check that the cuffs are still intact following intubation—it will be difficult to change the tube once the patient is on the table. Once the tube is in place, then inflate the tracheal cuff so you can ventilate both lungs satisfactorily. Then inflate the bronchial cuff with a small amount of air (say, 2–3 mls) just so that you will be able to see the cuff when viewing with the fibrescope. Its not important to have the bronchial cuff fully inflated at this stage.

Railroading the tube Sometimes intubation can be extremely difﬁcult, and the only way is to ‘railroad’ the tube over a bougie. Check that the bougie is long enough—at least 60 cm long (i.e., 35+25 cm). Railroading a double-lumen tube usually requires a fair bit of force, and so some care is necessary in order not to damage the trachea or lung. The aim is to keep the end of the bougie above the carina at all times. Since the carina is approximately 24–25 cms from the teeth (adult male), then in order to keep the end of the bougie above the carina (to avoid damage from inadvertently pushing it in too far) it is useful to make a clear mark on the bougie at about 24 cms, and maintain this at or above the teeth when railroading the tube. Since all tubes are now transparent, this mark will be easily visible through the tube wall.

If encountering problems, consider placing a single-lumen tube and checking the anatomy with a fibrescope If there are problems positioning the double-lumen tube then it is sometimes a good idea simply to replace it with a single-lumen tube and check the anatomy carefully with the fibrescope, rather than run the risk of making things worse (e.g., obstructing an upper lobe and collapsing it). Sometimes just checking you can identify the anatomy, or even measuring the distance to the carina or left subcarina, will greatly help during the next attempt at placing the double-lumen tube. Consider railroading the double-lumen tube over the fibrescope. Consider using a single-lumen tube and a bronchus blocker. The TEPID database can be a useful guide for tube size and length, especially in short patients (see Section 6.4.3). The commonest initial problems are (a) the tube keeps going down the wrong side, (b) the endobronchial part of the tube is too big and fails to go down the main bronchus, (c) the tube is in too far, (d) sometimes the endobronchial part of a left-sided tube is slightly too long for the patient, and a smaller tube is needed. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

7.3.3 Stethoscope check • Once the double-lumen tube is in place first check that there is good air entry (i.e., with no added sounds) to both upper lobes by listening with a stethoscope just inferior to (and touching) the clavicles. Air-entry here should sound exactly the same as for the lower lobes (see Chapter4 for surface markings). If there are any added sounds in the upper-lobe zone (or if it is quiet) then gently withdraw the tube about 1 cm at a time while listening until the air entry improves. For example, if after placing a left double-lumen tube we hear added sounds over the right upper lobe, then we can assume (providing it was clear before) that the tube has gone down the wrong side. Conversely, if the left upper lobe is now quiet, then we know the tube is down the correct side, and all we need to do is pull it back until we have good air entry in the left upper lobe. It is important to auscultate the upper lobes immediately and carefully after intubation because an undetected obstructed upper-lobe will very quickly collapse (within about 5 minutes); the speed being hastened partly by the high inspired oxygen typically used at this stage, and partly by the increased pressures generated by the ventilator.4 Once the lobe has collapsed, auscultation over the lobe may well seem quite normal, since the remaining lung expands to fill this space. If the collapsed lung is on the operation side (‘top’ side) then this will be revealed at thoracotomy.5 However, if this occurs on what will be the dependent side (‘bottom’ side) and goes un-noticed, then this could be disastrous—most probably resulting in severe hypoxia when on one lung. • Next, check air-entry to the lower lobes by listening on the mid-axillary line below the level of the nipples (see Figures 4.1 and 4.2 for surface markings). • Now check lung isolation. Clamp each side in turn and check (a) that there is no air-entry on the clamped side (add air to the bronchial cuff as necessary), and (b) that there is good air-entry on the opposite side. It should be easy to squeeze the bag when on one lung—any significant resistance at this stage is usually a sign that the tube is not correctly positioned. If in doubt, let the bronchial cuff down and then check further with the fibrescope—the bronchial cuff can be inflated later after confirming that the tube is correctly positioned.

• Mark the tube at the teeth (with a felt-tip pen) and then tie the tube in place using a rolling-hitch, as described recently by Frank Aldridge (Aldridge 2006), making sure the mark is visible above the knot and from the ‘top’ side (so you can see it once the patient is in the lateral position). This mark will be useful during the operation

4Note that the pressures generated by the ventilator tend to keep a partially obstructed lobe open. Once a lobe totally I is obstructed it will experience a net compression from the lung surrounding it. This, plus a high F O2 , results in rapid collapse of the lobe. 5This may be associated with some desaturation, especially while supine—see Section 7.2 CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

(to indicate if the tube has moved), and also at the end of the operation when the patient is supine again (the tube can be pulled back to its original anaesthetic-room position—see Section 7.6). Make sure that the two pilot balloons are inside the tie—if they remain outside there is the danger that they may be damaged if the tube position has to be adjusted and the knot moved along the tube. • Finally, suck out audible secretions at this stage (i.e., before using the ﬁbrescope).

7.3.4 Bronchoscopy — left-sided tube The strategy underlying placement of a left-sided tube has two aims as follows. 1. To position the bronchial cuff at or below the carina. 2. To position the tip of the tube proximal to the left subcarina.

Bronchoscope check—tracheal side We proceed by asking three questions.

1. Is the tube down the correct side? If not, then reposition the tube. If simple measures to reposition the tube fail (withdrawing the tube, turning the head to the right 6, advancing the tube again), then consider railroading the tube into the left main bronchus under direct vision over the fibrescope (place the fibrescope down the endobronchial (left) side; withdraw the tube so the end is just above the carina—usually at about 23–24 cms at the teeth in an average man; advance the fibrescope down the left main bronchus close to the left subcarina, and railroad the tube down to a suitable position). 2. Is there any bronchial cuff above the carina? If there is cuff above the carina, then push the tube down a bit further so the cuff is just below the carina. If you can’t see the cuff at all, then the tube may well be too far down (we check this later when looking down the endobronchial side). However, in view of the earlier stethoscope-check we should be confident at this stage that the tube is not so far down that it is compromising the left upper-lobe. 3. Is the tracheal lumen of the tube very close to the carina? If it is too close (less than one finger width) then the tube may well be too far down (see Section 5.3 on how to measure this distance).

Armed with all this information, we now bronchoscope the endobronchial side.

6Improves the alignment of the trachea with the left main bronchus. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

Figure 7.1: Left lung: medial supine view of the hilum—enlarged from Figure 4.6 and rotated into the supine position. Notice how in the supine position the bronchus to the (yellow) apical segment of the lower lobe descends vertically down from the ﬁrst part of the left lower-lobe bronchus—compare with Figure 7.2 where the oriﬁce is denoted by the letter A (From Brock (1942-1944), with permission).

Bronchoscope check—endobronchial side There are two stages.

1. Observe the carina and right main bronchus (dark circular shadow) through the plastic wall of the tube (i.e., looking medially). Notice the position of the bronchial cuff (blue) in relation to the carina—i.e., check to see that the top of the bronchial cuff is at or below the carina. 2. Position the end of the double-lumen tube optimumly in relation to the left subcarina, by noting the position of the upper and lower-lobe bronchi in relation to the end of the tube (see Figures 7.1 and 5.1). The closest the tube should be to the subcarina is when the oriﬁces of the two second-order bronchi either side of the left subcarina, together just ﬁt into the diameter of the end of the tube, as shown in the schematic diagram in Figure 7.2. The tube can of course be further out than this, providing that the bronchial cuff remains at or below the carina. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

Figure 7.2: Left: This is a schematic showing the position of the orifice of the lingula bronchus (Li) and the origin of the bronchus to the apical a segment (A) of the left lower lobe in relation to the second-order bronchi and the end of the double- lumen tube (dashed circle), as viewed down the fibrescope from the head end in a supine patient. This schematic depicts the closest safe approach of the end of the tube to the left subcarina. We can define this as being when the two diameters of the orifices of the second-order bronchi bordering the left subcarina just fit into the diameter of the end of the tube. Compare this with the bronchoscopic image on the right which shows the view seen when the tube is slightly too far down. Copyright © RWD Nickalls 2005 Right: View of the entrance of the left lower-lobe bronchus (same orientation as in the schematic on the left). If you see this view bordered by the end of the tube, then the tube is slightly too far down. The shadow at the 11 o’clock position is the orifice of the left upper-lobe bronchus (partially hidden by the end of the tube which is almost touching the left subcarina). Since the endobronchial end of the left double-lumen tube is unfortunately usually bevelled slightly medially b a tube in this position tends to look down into the left lower lobe, as illustrated here. The orifice at the 6 o’clock position is the entrance of the bronchus to the apical a segment of the left lower lobe; the remaining orifices are two basal bronchi c of the left lower lobe—compare with Figures 7.1, 4.6 and 5.2 (from the website of P Slinger d with permission).

aSometimes (wrongly) described as the superior segment. bThe tube should really be bevelled slightly laterally (i.e., to be facing the subcarina). cTwo of the three basal bronchi are visible at the 3 o’clock position dhttp://www.thoracic-anesthesia.com/ CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

7.3.5 Bronchoscopy — right-sided tube The strategy underlying placement of a right-sided tube has two aims as follows.7

1. To align the side hole with the right upper-lobe bronchus. 2. To ensure there is an adequate gap between the endobronchial part of tube and the wall of the upper part of the right main bronchus 8 (i.e., distal to the right upper- lobe bronchus). This is a useful precaution, since if the side hole later becomes mis-aligned (often the case once the patient has been turned into the lateral position) then the gases can still get in and out of the right upper-lobe by passing between the tube and the bronchial wall.

The commonest initial problem associated with placing a right double-lumen tube is to inadvertently position it too far down; the top of the medial part of the bronchial cuff needs to be extremely close to the carina—at least initially anyway.

Bronchoscopy—tracheal side Since it is generally necessary to have the bronchial cuff very close to the carina in order to align the side hole with the right-upper lobe bronchus, start by positioning the tube so that the medial side of the top of the bronchial cuff lies at or just below the carina (i.e., as close to the carina as possible). Note that the Mallinckrodt right-sided tube has a large amount of blue plastic cuff-material stuck to the tube above the bronchial cuff on the medial side, so look carefully to distinguish between the blue ‘real’ cuff and the reﬂected blue plastic on the tube proximal to the cuff. Having positioned the cuff close to the carina, then mark the tube on the top side at the teeth (with a felt-tip pen) making sure the mark is just visible above the knot.

Bronchoscopy—endobronchial side There are two stages.

1. Pass the fibrescope to the end of the tube and withdraw slowly looking towards the right-hand side of the tube until the side hole comes into view. Advance the fibrescope through the side hole and try and locate the right upper-lobe bronchus. If the bronchus or edge of the orifice is visible, then move the tube slightly (rotating it if necessary) in order to get maximum alignment. If the bronchus is not visible, then move the tube in and out slightly, repeating after a small rotation if necessary, until the right upper-lobe bronchus is found.

7Note that the algorithm for placing a right-sided double-lumen tube is signiﬁcantly different from that for placing a left-sided tube. 8This used to be called the bronchus intermedius—see Section 4.4 for correct nomenclature. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

2. Now proceed to determine whether there is an adequate gap (distal to the side hole) between the endobronchial part of the tube and the bronchial wall. Advance the ﬁbrescope through the side hole and try to look distally at the space between the tube and the bronchial wall. If there is a gap then it is usually fairly easy to see. Even if it seems quite small, this is usually acceptable since the gap will increase slightly when on ‘one-lung’ ventilation as the mean airway pressure will be increased then. If there is no gap at all, then consider using a smaller tube, or perhaps a bronchus blocker, unless you are conﬁdent you can maintain good alignment in the lateral position. For a given patient, I therefore use a smaller right-sided tube (one size smaller) than I would for a left-sided tube.

7.3.6 Final tidal volume and pressure check Just before turning the patient into the lateral position it is useful to check while the patient is still supine that the ventilator pressures and tidal volume generated by the theatre ventilator are appropriate. Strange pressures at this stage may suggest that all is not well with the tube position. As a general rule, a normal tidal volume (TV) and respiratory rate (RR) will generate a pressure on two lungs of about 20 cm H2O (average male using a 41 Fr double-lumen tube). Clamping the ‘top’ side should then result in the peak pressure rising to no more than 30–35 cm H2O, with a plateau of about 25 cm H2O. If the pressures are much different from these, then now is a good time to adjust the TV, ﬂow and RR accordingly—the ﬁne tuning can be done later. Aim to use the same TV and RR for one-lung as for two-lungs.

7.4 Turning the patient laterally

The initial bronchoscopy after turning the patient into the lateral position commonly shows some degree of tube malposition—sometimes major malposition—the bronchial cuff typically now appearing to be positioned slightly above the carina, even though it had been perfectly positioned when supine. The tube position, however, is generally unchanged relative to the teeth, since the tube is usually well tied in. The cause is therefore, not tube movement, but movement of the carina. The reality, therefore, is that turning patients from supine to the lateral position is often associated with signiﬁcant caudal movement of the carina. This is especially the case in obese patients, and those with a pronounced abdominal paunch. Conversely, there is rarely much movement of the carina in thin patients. This caudal movement of the carina is most likely due the fact that the diaphragm descends further once the patient is in the lateral position since the abdominal contents will move caudally and outwards. Consequently the lungs also descend, resulting in the carina being pulled downwards towards the bronchial cuff, with the effect that the bronchial cuff may then come to lie in the trachea. If turning is also associated with some outward CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

movement of the tube at the teeth, then catastrophic tube malposition can easily occur, with the end of the tube coming to lie in the trachea, or even in the wrong bronchus.

• Before turning first check that the patient is on two-lung ventilation. With a top- side tube consider temporarily deflating the bronchial cuff (leave the 5-ml syringe attached so you can easily inflate the cuff with the same volume afterwards). • In patients in whom the tube has been difficult to position, consider checking the ventilation pressures and volumes just prior to turning; these can serve as a useful guide after the patient has been turned (see Section 7.3.6). • Hold the tube at the mouth during turning, taking care to not to let the tube come out any distance at all. In an obese patient push the tube in slightly during turning to the lateral position (perhaps 1 cm) to compensate for the anticipated caudal movement of the diaphragm and hence of the carina also. • Once the patient is in the lateral position, check that you have easy access to the two pilot-cuff balloons. Reinflate the bronchial cuff if you deflated it prior to turning (keeping the syringe attached serves as a useful reminder). • Finally, check the tube position bronchoscopically and adjust accordingly. Try to do this before starting one-lung ventilation. If the cuff is now in the trachea, then check first whether or not the tip is still in the correct bronchus before pushing it further down. If already on one-lung ventilation, then consider returning to two-lung ventilation before repositioning the tube, since you can then deflate the bronchial cuff and see more clearly. You may be forced to deflate the bronchial cuff anyway if ventilation becomes obstructed while on one-lung. Deflate both cuffs before moving the tube in order to avoid damaging the trachea and bronchus.9 After repositioning the tube you may well have to tie the tube in again.

7.5 One-lung anaesthesia

It is convenient to consider the following stages: (a) preparation, (b) going on to one-lung, (c) management of one-lung anaesthesia, (d) returning to two-lungs, (e) turning supine, (f) extubation.

9A useful technique is to first attach an empty 5 and 10 ml syringe to the bronchial and tracheal cuffs respectively. When you are ready to advance the tube under bronchoscopic control, ask someone to deflate the cuffs—but to keep the syringes firmly attached. Once the tube is in the new position, the cuffs can be quickly inflated with the same volume which was withdrawn originally. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

7.5.1 Preparation • Check the position of the tube with the ﬁbrescope.

• Check the tidal volume (TV) and pressures. An average-sized man with a 41 Fr double-lumen tube and normal tidal volume and respiratory rate (say, 10/min) will have a peak inspiratory pressure with two- lung ventilation of approximately 20 cm H2O. With one-lung ventilation the peak inspiratory pressure typically increases to about 30 cm H2O. Two lungs: Check that the TV is reasonable and that the inspiratory pressure is 20 cm H2O. Use a relatively slow rate (say, 10 /min). ≤ One-lung: Clamp the top lung (at the end of expiration) just for a few breaths to see what TV and pressures are generated. Check that the inspiratory pressure rises smoothly and uniformly. Aim for a peak one-lung pressure of 30 cm H2O, with a ≤ plateau pressure of 27 cm H2O (Slinger 2003). If the peak pressure remains high, then exclude causes≤ of increased resistance (e.g., secretions, bronchospasm, tube too far in etc). If the plateau pressure remains high with a reasonable TV, then check the tube position. If the tube position is ﬁne, then consider reducing the TV slightly, and adjusting the respiratory rate as necessary.

• Check the end-tidal PCO2. If this is high, then try to bring this down to normal values before the surgeons need one-lung ventilation. • Have a Jackson-Rees paediatric T-piece circuit available on a separate oxygen ﬂowmeter for use later with the top lung.

7.5.2 One-lung ventilation For an excellent overview regarding the possible options for managing hypoxaemia during one-lung ventilation see the recent article by Roze,´ Lafargue and Ouattara (2011)

• Before going on to one-lung ventilation (a) note the tidal volume, end-tidal PCO2,

saturation and airway pressures (peak and plateau), and (b) increase the FIO2 to at least 50%. If using nitrous oxide and a volatile remember to increase the volatile concentration when reducing the nitrous oxide concentration in order to maintain the same MAC— see Figures 9.1, 9.2, 9.3. • Go on to one-lung ventilation by clamping the top lung (proximal to the suction oriﬁce) at the end of expiration, and open the suction oriﬁce to air (to allow the top lung to collapse). CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

• Check that the tidal volume and airway pressures are appropriate on one-lung. If there is an air-leak check that the bronchial cuff is adequately inﬂated. If the airway pressures are too high coupled with a small TV consider going back on to two lungs and reviewing the tube position.

• Check to see if the top lung is deﬂating (ask the surgeons if necessary). • Check for auto-PEEP. Listen to the bottom tube with a stethoscope (use the diaphragm) while watching the airway-pressure dial, and check that (a) the inspiratory and expiratory breath sounds are clear and uniform, and (b) no auto-PEEP is being generated (i.e., check there is an end-expiratory pause). If there is no end-expiratory pause then lengthen the expiratory phase by ﬁrst reducing the respiratory rate (see the excellent paper by Szegedi et al. 2002), and adjust the TV as necessary to minimise rise in end-tidal PCO2. Suck out any audible secretions.

• If everything is fine (and the lungs are visible 10) then connect the Jackson-Rees T-piece (with 100% oxygen at about 1–2 L/min) to the top lung. It seems that even when the lung has collapsed down there is significant entrainment of gas by the lung (see articles by Pfitzner et al. 1999; 2001), and so the idea of the T-piece is to allow oxygen to be entrained by the lung instead of air. Have the oxygen enter the T-piece as close to the double-lumen tube as possible. Check that the T-piece bag has a hole in it (note that some disposable T-piece circuits use a valve and a closed reservoir bag).

• Check that the pulse, blood pressure and end-tidal PCO2 are satisfactory. • Start monitoring the saturation more closely as this will usually begin to fall over the next few minutes.

7.5.3 Management of one-lung anaesthesia There are some general concepts worth bearing in mind.

• Keep the saturation 90% by increasing the FIO as necessary. ≥ 2 In particular, avoid the combination of low saturation plus low cardiac output (i.e., low oxygen delivery to the coronaries). To this end, avoid giving very much down the epidural until the saturation and BP have stabilised at a reasonable level. If necessary periodically squeeze oxygen into the top lung manually 11 in order to

10This precaution lessens the risk of barotrauma should the hole in the T-piece bag become obstructed— providing the surgeons can see the lung they will alert you if the lung starts expanding. 11E.g., using a paediatric T-piece circuit. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

maintain an adequate oxygenation (avoid applying PEEP to the bottom lung—unless the patient is obese—as this generally makes matters worse by shunting more blood to the top lung). Once you know you can control the saturation at a reasonable level, then gradually ‘top-up’ the epidural as necessary.

• Avoid excessive ventilator pressures. Slinger (2003) highlights the association of postoperative acute lung injury with plateau ventilatory pressures on one lung > 27 cm H2O.

• Try to keep the end-tidal PCO2 below 5 5 kPa. · The end-tidal to arterial PCO2 difference can be quite large on one-lung (Ip-Yam PC et al. 1994), so it is best to try and keep the end-tidal level reasonably low to avoid a 12 respiratory acidosis. Do a blood-gas to check the PaCO2 if necessary. As a general rule the end-tidal PCO2 is a poor guide to the arterial PCO2 if it does not plateau out, in which case a blood gas is more useful.

• Suction out the top lung periodically. • Periodically check the tube position with the fibrescope. Avoid looking down the ‘bottom’ lung unnecessarily at this stage in order to keep the bottom lung well inflated, since there is always a leak when using the fibrescope. Once you are happy the tube is correctly positioned, then top lung bronchoscopy will serve as a guide to tube movement. With a right-sided double-lumen tube check (a) the alignment of the side hole with the right-upper lobe orifice, and (b) the position of the bronchial cuff in relation to the carina. When a left-sided tube is used in the bottom lung avoid having the end of the tube too close to the subcarina (danger of the tube obstructing the upper-lobe of the bottom lung). Conversely, when a left-sided tube is used in the top lung avoid having the bronchial cuff too close to the carina (danger of the bronchial cuff herniating above the carina and obstructing gas flow to the bottom lung). • Control hypotension with fluids and/or vasoconstrictors as necessary. A thoracic epidural will usually make the hands vasodilate significantly, and this, when it occurs, is a helpful sign. Metariminol (10 mg in 20 mls saline; dose 1–2 mls) seems to be better and longer lasting than phenylephrine (1 mg in 20 mls saline; dose 1–2 mls). If having to give frequent boluses, then consider a noradrenaline infusion (2 mg in 50 mls saline; rate 2–8 mls/hr)—see also Section 8.1. Consider dopamine (200 mg in 50 mls; rate 2–8 mls/hr) for bowel surgery (e.g., oesophagectomy).

12Make a note of the arterial–end-tidal difference for use as a guide later. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

• Avoid excessive IV fluids, especially crystalloids. Slinger (2003) highlights the association of postoperative acute lung injury with excessive IV fluids in the first 24 hours. Limit crystalloids to about 1 L, and then use only Gelofusin or blood depending on the haematocrit. If the patient is clearly vasodilated (perhaps from the epidural) then consider using a noradrenaline infusion (Section 8.1). Aim to be more conservative with fluids for a pneumonectomy.

7.5.4 Returning to two-lungs • Always suction out the top lung before inflating it. • Following a lobectomy or pneumonectomy the surgeons will usually wish to test the stump under water using inflation pressures of approximately 30–40 cms water, so remember to remove the tube clamp and close the suction orifice. If there is a lung leak then you may need to return to one-lung for a while before testing the stump again. Once the surgeons are happy with the stump then return to two-lung ventilation (with smaller tidal volumes perhaps while the chest drains are inserted). Sometimes going back on to two-lungs is associated with a fall in blood pressure, so be prepared to infuse fluids or give vasoconstrictors at this stage.

• Once the saturation is adequate, then the FIO2 can be reduced as necessary. Remem- ber to reduce the volatile concentration (if adding nitrous oxide) in order to avoid an unduly high total-MAC. • Check all parts of the lung are adequately inﬂated before the surgeons close the chest completely. • Adjust the epidural rate/dose as necessary so as to have given an adequate amount before the end of the operation (i.e., at least 15–20 mls 0 25% bupivicaine before the end). · • Make sure the chest drains are attached to the under-water seal as soon as the chest is air-tight. Check that the chest-drain bottles are attached correctly (i.e., chest drains are attached directly to the under-water seal tube) and that the under-water seal is working. Check also that the air-exit hole is not obstructed—remove the bung completely if in doubt. Inﬂate the lungs manually a few times to remove as much of the residual air as possible.

7.6 Turning the patient supine

Turning the patient from the lateral position (on the table) to supine onto the HDU bed is a particularly hazardous moment (see Pearce and Gould 2005) with respect to cardiac arrest CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

(the heart can get trapped in a pericardial window—cardiac herniation), exsanguination (a vascular tie can slip or work loose) and tension pneumothorax (a chest drain can become occluded).

• Keep the saturation probe and the arterial line attached and running (monitoring) until after extubation to safeguard against overlooking signiﬁcant haemodynamic or respiratory changes.

• Increase the FIO2 to 100%. • The effect of changing posture back to the supine position will cause the carina to move cranially (see Section 7.4), with the effect that the endobronchial part of the tube may inadvertently occlude the upper lobe bronchus. Following a pneumonectomy, hypoxia at this stage may indicate an obstructed upper lobe. Such problems can be avoided by (a) pulling the tube back out to the position it had in the anaesthetic room (i.e. look for the mark on the tube—see Section 7.3.3), and (b) sitting the patient up somewhat. • Check the chest drains for any signiﬁcant blood loss or air leak. • If the patient is to be electively ventilated in ITU then change the tube to a single lumen tube before going to ITU. Suction out both lungs before changing the tube.

7.7 Extubation

• Position the patient sitting up at about 45 degrees. • Suction out both lungs before extubation. • If the operation is a pneumonectomy, then just prior to extubation remember to inﬂate the lung well and clamp the chest drain (two clamps) while the pressure is maintained (usually only one drain following a pneumonectomy).

7.8 Complications

7.8.1 Intraoperative Most intraoperative complications are tube & airway related (e.g., damage to the trachea or bronchus), obstruction from tracheal compression (thyroid surgery, big mediastinal tumours), lung collapse secondary to failure to position the tube correctly. Other signiﬁcant problems are pneumothorax of the dependent lung (often difﬁcult to diagnose for cer- tain), hypotension, major blood loss, bradycardia/cardiac arrest (carcinoid tumours—see Figure 8.1). CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

An unusual but dramatic complication which is easily treated, is an acute unilateral pulmonary oedema which arises from the operative side as a result of an inadvertent acute incarceration or twisting of the exposed lung causing an obstruction of venous outﬂow of a section of lung. Typically occurring after a period of one-lung anaesthesia, the oedema arises from a piece of lung which the surgeon has pushed to one side away from the operative ﬁeld. Bronchoscopy demonstrates the oedema is associated with the operative side. The surgeon should immediately and carefully check all the collapsed lung for any twisting, which once straightened, will resolve the problem quite quickly.

• Burton NA, Fall SM, Lyons T and Graeber GM (1983). Rupture of the left main-stem bronchus with a polyvinylchloride double-lumen tube. Chest; 83, 928–929. • Gilbert TB, Goodsell CW and Krasna MJ (1999). Bronchial rupture by a double- lumen endotracheal tube during staging thoracoscopy. Anesthesia and Analgesia; 88, 1252–1253. • Hannallah M and Gomes M (1989). Bronchial rupture associated with the use of a double-lumen tube in a small adult. Anesthesiology; 67, 457–459. • Mackie AM and Watson CB (1984). Anaesthesia and mediastinal masses; a case report and review of the literature. Anaesthesia; 39, 899–903. [30 refs] • Sakuragi T, Komano K, Yasumoto M and Dan K (1997). Rupture of the left mainstem bronchus by the tracheal portion of a double-lumen endobronchial tube. Acta Anaesthesiol. Scand.; 41, 1218–1220. • Skobel E, Gehbauer G, Hanna P, Breuer C (2004). Bronchoscope observations after conservatively postintubation tracheobronchial rupture. Chest Medicine on-line; http://www.priory.com/cmol/skobel.htm • Smith BAC and Hopkinson RB (1984). Tracheal rupture during anaesthesia. Anaes- thesia; 39, 894–898. [19 refs + literature search] • Wagner DL, Gammage G and Wong ML (1985). Tracheal rupture following insertion of a disposable double-lumen tube. Anesthesiology; 63, 698–700.

7.8.2 Postoperative Pulmonary complications are the leading cause of morbidity in the postoperative thoracic patient; for example atelectasis, secretions, lower respiratory infection and ventilator insufﬁciency. Postoperative bronchoscopy therefore has a major role in managing these common and potentially life-threatening complications. All too often bronchoscopy is unduly delayed; it should be seen as an adjunct to physiotherapy and other more routine elements of postoperative care, and not viewed as a treatment of last resort. See the excellent review and pointer to recent literature by Keith and Kernstein (2005). This is on the CD. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

Sometimes a small/moderate bronchial tear is found at routine postoperative bronchoscopy; this will usually heal well if left alone (see Skobel et al. 2004 above).

• Bolliger CT, Jordan P, Soler M, Stulz P, Tamm M, Wyser Ch, Gonon M and Perru- choud AP (1996). Pulmonary function and exercise capacity after lung resection. Eur. Respir. J.; 9, 415–421. • Duggan M and Kavanagh BP (2005). Pulmonary atelectasis. [review article] Anesthesiology; 102, 838–854. • Keith J and Kernstine K (2005). The role of bronchoscopy in the prevention of common post-thoracotomy pulmonary complications: bronchoscopy in thoracic patients: an emphasis on post-thoracotomy bronchoscopy. Virtual hospital; http: //www.uihealthcare.com/vh/

Acute lung injury/pulmonary oedema An excellent editorial by Slinger (2003) comments on the ﬁndings of Licker et al. (2003), and highlights four factors thought to be signiﬁcant independent risk factors for ‘acute lung injury’ following one-lung anaesthesia, namely (a) excessive intravascular volume, (b) high intraoperative ventilatory pressures (> 27 cm H2O), (c) pneumonectomy, (d) preoperative alcohol abuse. Suggested guidelines for the management of one-lung anaesthesia are as follows.

1. Avoid over inflation of the dependent lung. Consider using smaller (more physiological) tidal volumes if possible (say, 5 mls/kg) plus oxygen insufflation, and with PEEP if necessary. Limit plateau inspiratory pressures to <25 cm H2O. 2. Minimise pulmonary intravascular pressures. This is primarily by fluid restriction, but also by minimising hypercarbia and hypoxia.

To this end a plot of the Datex AS/3 monitor’s plateau ventilatory pressure (Pplateau) was added to our computer-generated anaesthetic record sheet, in order to have a record of this parameter in the notes, as shown in Figure 8.1 (page 135).

• Hayes JP, Williams EA, Goldstraw P and Evans TW (1995). Lung injury in patients following thoracotomy. Thorax; 50, 990–991. [7 refs; about incidence of ARDS and pulmonary oedema postoperatively] • Licker M, de Perrot M, Spiliopoulos A, Robert J, Diaper J, Chevalley C and Tschopp J-M (2003). Risk factors for acute lung injury after thoracic surgery for lung cancer. Anesthesia and Analgesia; 97, 1558–1565. [49 refs; see also editorial by Slinger (2003)] • Mathru M, Blakeman B, Dries D, Kleinman B and Kumar P (1990). Permeability pulmonary oedema following lung resection. Chest; 98, 1216–1218. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

• Peters RM (1989). Post-pneumonectomy pulmonary oedema. Appl. Cardiopulmon. Pathophysiol.; 3, 43–51. • Slinger PD (2003). Acute lung injury after pulmonary resection: more pieces of the puzzle. Anesthesia and Analgesia; 97, 1555–1557. [editorial relating to article by Licker et al. (2003)] • Williams EA, Evans TW and Goldstraw P (1996). Acute lung injury following lung resection: is one-lung anaesthesia to blame? Thorax; 51, 114–116. [41 refs] • Wittnich C, Trudel J, Zidulka A and Chiu RC (1986). Misleading “pulmonary wedge pressure” after pneumonectomy: its importance in postoperative ﬂuid therapy. Ann. Thoracic Surg.; 42, 192–196.

Pneumonectomy The recent UK pneumonectomy outcome study (Powell et al. 2009) showed that The major complication incidence was: 30-day mortality 5.4%; treated cardiac arrhythmia 19.9%; unplanned intensive care unit admission 9.3%; further surgery 4.8%; inotrope usage 3.5%. Age, ASA physical status P3, pre-operative diffusing capacity for carbon monoxide (DLCO) and epidural≥ analgesia were collectively the strongest risk factors for major complications.

7.9 General references

• Aldridge F (2006). Get a grip! A knotty problem solved Anaesthesia, 61, 822. [An insightful new approach to tying the tube in securely.] See also: Knots on the web (http://www.earlham.edu/~peters/knotlink.htm); Rolling Hitch (http://en.wikipedia.org/wiki/Rolling_hitch); Rolling Hitch (http://www.apparent-wind.com/knots/rolling-hitch/) • Alliaume B, Coddens J and Deloof T (1992). Reliability of auscultation in positioning of double-lumen endobronchial tubes. Can. J. Anaesth., 39, 689–690. • Bahk J-H (1999). Prediction of double-lumen tracheal tube depth. J. Cardiothoracic Vasc. Anesth.; 13, 370–371. • Benumof JL, Partridge BL, Salvatierra C and Keating J (1987). Margin of safety in positioning modern double-lumen endotracheal tubes. Anesthesiology; 67, 729–738. • Benumof JL (1988). Improving the design and function of double-lumen tubes. J. Cardiothorac. Vasc. Anesth.; 2, 729–733. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

• Boucek CD, Landreneau R, Freeman JA, Strollo D and Bircher HG (1998). A comparison of techniques for placement of double-lumen endo-bronchial tubes. Journal of Clinical Anesthesia, 10, 557–560. [from Cheong & Koh 1999] • Brodsky JB (2000). Placement of double lumen tubes—time to shed light on an old problem. Br. J. Anaesth., 85, 166–167 [reply to Pennefather/Russell editorial above; 16 refs]. • Brodsky JB (1988). Con: proper positioning of a double-lumen tube can only be accomplished with the use of endoscopy. J, Cardiothoracic Vasc, Anesth.; 2, 105–109.

• Brodsky JB, Benumof JL and Ehrenwerth J et al. (1991). Depth of placement of double-lumen endobronchial tubes. Anesthesia and Analgesia; 73, 570–572. • Brodsky JB, Macario A and Mark JBD (1996). Tracheal diameter predicts double- lumen tube size: a method for selecting left double-lumen tubes. Anesthesia and Analgesia; 82, 861–864. • Brodsky JB, Macario A, Cannon WB and Mark JBD (1995). ‘Blind’ placement of plastic left double-lumen tubes. Anesth. Intensive Care; 23, 583–586. • Brodsky JB and Mark JBD (1983). A simple technique for accurate placement of double-lumen endobronchial tubes. Anesthesiol. Rev.; 10, 26–30.

• Brodsky JB, Shulman MS and Mark JBD (1985). Malposition of the left sided double-lumen endobronchial tubes. Anesthesiology; 62, 667–669. • Campos JH, Massa and Kernstine KH (2000). The incidence of right upper-lobe collapse when comparing a right-sided double-lumen tube versus a modified left double-lumen tube for left-sided thoracic surgery. Anesthesia and Analgesia; 90, 535–540. • Cheong KF and Koh KF (1999). Placement of left-sided double-lumen endobronchial tubes: comparison of clinical and fibreoptic-guided placement. Br. J. Anaesth.; 82, 920–921. [compared blind intubation with intubation with the the fibrescope already in the tracheal lumen watching the tip and bronchial cuff as you approach the carina and left main bronchus. They preferred the second method as easy and more reliable in awkward cases.] • Chow MYH and Ip-Yam PC (2000). Placement of double-lumen tubes. Br. J. Anaesth.; 85, 332 [reply to Pennefather/Russell editorial above; 11 refs].

• Dyer RA, Heijke SAM, Russell WJ, Bloch MB and James MFM (2000). Can insertion length for a double-lumen endobronchial tube be predicted? Anaesthesia CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

and Intensive Care; 28, 666–668. [they compared (separately) height, weight, and the external surface distance (sternal-angle to ear-lobe via mouth) and found no useful correlation] • Ehrenwerth J (1988). Pro: proper positioning of a double-lumen tube can only be accomplished with endoscopy. J. Cardiothoracic Vasc. Anesth.; 2, 101–104. • Fortier G, Cote D, Bergeron C and Bussieres JS (2001). New landmarks improve the positioning of the left Broncho-Cath double-lumen tube—comparison with the classic technique. Can. J. Anaesth.; 48, 790–794.

• Hannallah MS, Benumof JL and Ruttiman UE (1995). The relationship between left mainstem bronchial diameter and patient size. J. Cardiothorac. Vasc. Anesth.; 9, 119–121. [see also editorial pp. 117–118; and article pp. 784–785] • Inoue S, Nishimine N, Kitaguchi K, Furuya H and Taniguchi S (2004). Double- lumen tube location predicts tube malposition and hypoxaemia during one lung ventilation. Br. J. Anaesth.; 92, 195–201. • Joseph JE and Merendino KA (1957). The dimensional interrelationships of the major components of the human tracheobronchial tree. Surg. Gynecol. Obstet.; 105, 210–214. • Nystrom PG (2003). Reverse assembly of a double-lumen tube. Anesthesia and Analgesia; 96, 1536. • Pearce A and Gould G (2005). Thoracics. In: Allman KG, McIndoe AK and Wilson IH (Eds.) Emergencies in Anaesthesia, 1st. ed., pp. 193–220 (Oxford University Press). • Pennefather SH and Russell GN (2000). Placement of double lumen tubes—time to shed light on an old problem. Br. J. Anaesth.; 84, 308–310 [editorial—see several replies below]. • Pﬁtzner J (2000). One-lung anaesthesia: the need for renewed respect. Br. J. Anaesth.; 85, 331 [reply to Pennefather/Russell editorial above; 2 refs].

• Powell ES et al. 2009. UK pneumonectomy outcome study (UKPOS): a prospective observational cohort study of pneumonectomy outcome. Journal of Cardiothoracic Surgery; 4, 41– • Russell WJ (1996). Further reﬂections on ‘a blind guided technique for placing double-lumen endo-bronchial intubation’. Anaesthesia and Intensive Care; 24, 123.

• Russell WJ (1992). A blind guided technique for placing double-lumen endobronchial tubes. Anaesthesia and Intensive Care; 20, 71–74. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

• Sanders D (2006). Thoracic surgery. In: Allman KG and Wilson IH (Eds.) Oxford Handbook of Anaesthesia, 2nd. ed., pp. 351–383 (Oxford University Press). • Sanjay PS, Miller SA, Corry PR, Russell GN and Pennefather SH (2006). The effect of gel lubrication on cuff leakage of double lumen tubes during thoracic surgery. Anaesthesia, 61, 133-137. [gel lubrication of the tracheal cuff signiﬁcantly reduced leakage past the cuff] • Slinger P [Ed.] (2008). Thoracic anesthesia. Anesthesiology Clinics; 26 (June), 241–398 (Elsevier, Inc) [chapters: Evidence-based management of one-lung ventilation / Oxygen toxicity during one-lung ventilation: is it time to re-evaluate our practice? / Anesthetic considerations for airway stenting in adult patients / Perioperative anesthetic management for esophagectomy / Anesthetic considerations for patients with anterior mediastinal masses / The emerging role of minimally invasive surgical techniques for the treatment of lung malignancy in the elderly / Prevention and management of perioperative arrhythmias in the thoracic surgical population / Pulmonary vasodilators—treating the right ventricle / Post thoracotomy pain management problems / Postthoraco- tomy paravertebral analgesia: will it replace epidural analgesia? / Advances in extracorporeal ventilation ] • Slinger P (2001). Lung isolation in thoracic anesthesia: state of the art. Can. J. Anaesth.; 48, R3-3 • Slinger P (1995). Choosing the appropriate double-lumen tube; a glimmer of science comes to a dark art [editorial]. J. Cardiothorac. Vasc. Anesth.; 9, 117–118. [see also article on pp. 784–5] • Slinger PD (1989). Fibreoptic bronchoscopic positioning of double-lumen tubes. J. Cardiothoracic Vasc. Anesth.; 3, 486–96. • Yasumoto M, Higa K, Nitahara K, Shono S and Hamada T (2006). Optimal depth of insertion of left-sided double-lumen endobronchial tubes cannot be predicted from body height in below average-sized adult patients. European Journal of Anaesthesi- ology, 23, 42–44. [Japanese subjects of height 155 cm] ≤ 7.9.1 Tracheostomy and one-lung ventilation • Robinson RJ (1997). One-lung ventilation for thoracotomy using a Hunsaker jet ventilation tube. Anesthesiology; 87, 1572–1574. • Tobias JD (2001). Variations on one-lung ventilation. J. Clin. Anesth.; 13, 35–39. • Uzuki M, Kanaya N, Mizuguchi A et al. (2003). One-lung ventilation using a new bronchial blocker in a patient with tracheostomy stoma. Anesthesia and Analgesia; 96, 1538–1539. CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

7.9.2 One-lung anaesthesia • Bassi A, Milani WRO, El Dib R and Matos D (2009). Intravenous versus inhalation anaesthesia for one-lung ventilation (Review). The Cochrane Library; 2009, issue 3. (pp. 23) (http://www.thecochranelibrary.com/) • Levin AI and Coetzee JF (2005). Arterial oxygenation during one-lung anesthesia. Anesth. Analg.; 100, 12–14. • Levin AI, Coetzee JF and Coetzee A (2008). Arterial oxygenation and one-lung anesthesia. Current Opinion in Anaesthesiology; 21, 28–36. [107 refs] • Licker M, de Perrot M, Spiliopoulos A, Robert J, Diaper J, Chevalley C and Tschopp J-M (2003). Risk factors for acute lung injury after thoracic surgery for lung cancer. Anesthesia and Analgesia; 97, 1558–1565. [49 refs; see also editorial by Slinger (2003)] • Pearce A and Gould G (2005). Thoracics. In: Allman KG, McIndoe AK and Wilson IH (Eds.) Emergencies in Anaesthesia, 1st. ed., pp. 193–220 (Oxford University Press). • Pfitzner J, Peacock MJ and Daniels BW (2001). Administering ambient pressure oxygenation to the non-ventilated lung during thoracoscopic surgery. Anaesthesia; 56, 281–282. • Pfitzner J, Peacock MJ and Daniels BW (1999). Ambient pressure oxygen reservoir apparatus for use during one-lung anaesthesia. Anaesthesia; 54, 454–458. • Pfitzner J, Peacock MJ and McAleer PT (1999). Gas movement in the nonventi- lated lung at the onset of single-lung ventilation for video-assisted thoracoscopy. Anaesthesia; 54, 437–443. • Roze´ H, Lafargue M and Ouattara A (2011). Case scenario: management of intraoperative hypoxemia during one-lung ventilation. Anesthesiology; 114, 167–174. [55 refs] • Slinger PD (1989). Fibreoptic bronchoptic positioning of double-lumen tubes. J. Cardiothoracic Anesthesia; 3, 486–496. • Slinger PD (1990). Anaesthesia for lung resection. Can. J. Anaesth.; 37, Sxv–Sxxiv. [106 refs; part of the refresher course outline] • Slinger PD (1995). New trends in anaesthesia for thoracic surgery including thoracoscopy. Can. J. Anaesth.; 42, R77–R84. [part of the refresher course outline] • Slinger PD (2003). Acute lung injury after pulmonary resection: more pieces of the puzzle. Anesthesia and Analgesia; 97, 1555–1557. [editorial relating to article by Licker et al. (2003)] CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

• Slinger PD (2005). Management of one-lung anesthesia. Anesthesia and Analgesia; (Supplement: IARS 2005 Review Course Lectures; pp. 89–94) [52 refs]

• Slinger PD (2007). Lung isolation review. (http://www.thoracic-anesthesia. com/) • Strachan L (2006). One-lung ventilation. Update in Anaesthesia (June 2006), p. 20–23. http://update.anaesthesiologists.org/2006/ • Szegedi LL, Bardoczky GI, Engelman EE and d’Hollander AA (1997). Airway pressure changes during one-lung ventilation. Anesthesia and Analgesia, 84, 1034– 1037. • Szegedi LL, Barvais L, Sokolow Y, Yernault JC and d’Hollander AA (2002). Intrinsic positive end-expiratory pressure during one-lung ventilation of patients with pulmonary hyperinﬂation. Inﬂuence of low respiratory rate with unchanged minute volume. Br. J. Anaesth.; 88, 56–60. [decreasing RR while maintaining MV decreases PEEPi while maintaining PCO2.]

7.9.3 Tracheal bronchus See article by Ho et al. (2004) for a brief review of the recent literature

• Conacher ID (2000). Implications of a tracheal bronchus for adult anaesthetic practice. Br. J. Anaesth.; 85, 317–321.

• Ho AM-H, Karmakar MK, Lam WW, Lam FO, Lee TW, Ng SK and Chung DC (2004). Does the presence of a tracheal bronchus affect the margin of safety of double-lumen tube placement? Anesthesia and Analgesia; 99, 293–295. [reviews the recent literature on tracheal bronchus — nearly all are on the right-hand side and within 2 cm of the carina; 10 refs]

• Ikeno S, Mitsuhata M, Saito K, Hirabayashi Y, Akazawa S, Kasuda H and Shimizu R (1996). Airway management for patients with a tracheal bronchus. Br. J. Anaesth.; 76, 573–575.

7.9.4 Physiology & pathology • Abe K et al. (1998). The effects of propofol, isoflurane and sevoflurane on oxygenation and shunt fraction during one-lung anaesthesia. Anaesthesia & Analgesia, 87, 1164–1169. [propofol was best] • Burwell DR and Jones JG (1996). The airways and anaesthesia; I: anatomy, physiology and fluid mechanics. Anaesthesia; 51, 849–857. (September issue) II: pathophysiology. Anaesthesia; 51, 943–955. (October issue) CHAPTER 7. ONE-LUNG ANAESTHESIA RWD Nickalls 

• Cohen E (1997). Anesthesia. Physiology of the lateral position and one-lung ventilation. Chest Surgery Clinics of North America; 7(4) (November), 753–771. (WB Saunders Company) • Eisenkraft JB (1994). Anaesthesia and hypoxic pulmonary vasoconstriction. In: Recent advances in anaesthesia and analgesia 18; Chapter 7, pp. 103–122. [86 refs] • Ip-Yam PC, Innes PA, Jackson M et al. (1994). Variation in the arterial to end-tidal

PCO2 difference during one-lung thoracic anaesthesia. Br. J. Anaesth.; 72, 21–24. • Peltola K (1983). Central haemodynamics and oxygenation during thoracic anaesthesia. Acta Anaesthesiol. Scand.; 275, 1–42. • Portch D and McCormick B (2009). Pulmonary function tests and assessment for lung resection. Update in Anaesthesia (June 2009), p. 13–21. http://update. anaesthesiologists.org/2009/ • Ross AF and Ueda K (2010). Pulmonary hypertension in thoracic surgical patients. Current Opinion in Anaesthesiology; 23, 25–33. • Staub NC (1985). Site of hypoxic vasoconstriction. Chest; 88 (Suppl), 24S–45S. • Sykes K (1999). Pulmonary physiology during one-lung ventilation. In: Ghosh S and Latimer RD [Eds] Thoracic anaesthesia: principles and practice, Chapter 2, pp. 24–41. (Butterworth–Heinemann, Oxford, UK).

7.9.5 Flow/pressure/volume loops • Bardoczky GI, Vries J de, Merilainen¨ P, Schoﬁeld J and Tuomaala L (2006). Appligu- ide: patient spirometry—monitoring of patient ventilation during anesthesia. (GE Healthcare, Finland). pp. 46 [excellent—available as a PDF from GE Healthcare, Technical Department] • Fernandez-P´ erez´ ER and Hubmayr RD (2006). Interpretation of airway pressure waveforms. Intensive Care Med.; 32, 658–659.

• Kryger et al. (1976). Diagnosis of obstruction of the upper and central airways. Ann. J. Med.; 61, 85–93. 8 Drugs

8.1 Cardiovascular drugs

The key to using these drugs effectively is knowing the likely side effects, appropriate dilutions and safe bolus doses. Learn how to bolus the drugs listed in Table 8.2 (see Section 8.1.2) using a 1 ml syringe—very useful when the pumps/power fail. Use dedicated CVP ports—one drug per port. Avoid piggy-backing several drugs together, especially when titrating a new drug infusion. Always reduce infusions slowly and review the effect—avoid stopping these infusions suddenly as blood pressure may fall rapidly. Check infusions will not run out during transfer to and from ITU.

Table 8.1: Commonly used drugs for rapid bolus control of hypotension in adults (70 kg).

Drug Dilution (in saline) Bolus dose Ephedrine 30 mg/5 ml 0 5–1 ml 30 mg/1 ml ampoule · Metaraminol (Aramine) 10 mg/20 mls 0 5–1 ml 10 mg/1 ml ampoule · Phenylephrine 1 mg/20 mls 0 5–1 ml 1 mg/10 ml ampoule · Methoxamine (Vasoxine) 20 mg/20 mls 0 5–1 ml 20 mg/1 ml ampoule ·

126 CHAPTER 8. DRUGS RWD Nickalls 

• Adrenaline has both α and β effects.

• Dobutamine has a predominant β1 effect (inotropic & chronotropic), with minimal effect on peripheral vascular resistance (due to its modest β2 and α effects). Dobutamine is the only catecholamine administered as a racemic mixture. It is this mixture which results in its characteristic β1 selectivity, since the ve isomer is an α agonist, while the +ve isomer is an α antagonist (Zaritsky and− Chernow 1988). Dobutamine may cause hypokalaemia. • Ephedrine is a so-called ‘indirect’ agonist, as it causes release of catecholamines (α + β) at the terminal, and hence tachyphylaxis occurs with frequent use. It causes a moderate increase in BP and HR. If ephedrine fails to have much effect,1 then consider using a pure α-agonist (e.g., metaraminol, phenylephrine, noradrenaline). Avoid using ephedrine if HR > 100. For useful references regarding ephedrine and phenylephrine see Cooper (2005), Gambling DR and McLaughin KR (2010). See editorial by Smiley (2009) regarding use in Cesarean section. • Isoprenaline has almost pure β effects. Used almost exclusively to increase the heart rate in patients with acute complete heart block. • Metaraminol is a pure α-agonist. An IV bolus lasts about 5–10 minutes and commonly elicits a small reflex bradycardia (therefore avoid using if bradycardia exists). Metaraminol is slightly longer acting than than phenylephrine, and is therefore better for bolus use. If you need to give multiple metaraminol boluses then consider using a noradrenaline infusion via a CVP line (see below). If no CVP line then metaraminol can be used as a 5 mg IM dose, or as a temporary slow infusion (5–10 mg in 1 litre). • Noradrenaline is an almost pure α-agonist. It does actually have a very small β effect on heart rate, and, unlike metaraminol, does not cause a reflex bradycardia with bolus doses. Contrary to popular opinion, a noradrenaline infusion for supporting a normal blood pressure is generally beneficial to the kidney and renal function in sepsis (Lee et al. 2004; Bellomo and Giantomasso 2001). Noradrenaline is often of value both operatively and postoperatively in patients with a history of hypertension, to counteract the vasodilatory effects of anaesthesia (general and epidural) and maintain their normal preoperative blood pressure and renal function. • Phenylephrine is a pure α-agonist. It seems to have a slightly shorter duration of action compared to metaraminol, but otherwise its action is essentially similar to metaraminol. See related references cited for Ephedrine above. • Terlipressin (triglycyl-lysine-vasopressin) is a pro-drug which breaks down to the active lysine-vasopressin (Kam, Williams and Yoong 2004). Terlipressin is often

1If initial doses of ephedrine fail to have much effect, then this is usually a sign of sepsis and that noradrenaline should be used instead. CHAPTER 8. DRUGS RWD Nickalls 

used in ITU to supplement a noradrenaline infusion in septic shock (better blood pressure control, less tachycardia, better renal and gut perfusion). The adult dose is 1–2 mg IV (repeat 4-hourly initially); effect half-life is 6 hrs. • Vasopressin (ADH) is increasingly being used in septic shock to supplement a noradrenaline infusion (see Roth 2006; Kam, Williams and Yoong 2004, Sun et al. 2003). Vasopressin (American Pharmaceuticals) is available in ampoules of 20 U/ml.

8.1.1 Infusions: dilutions and use An important but commonly overlooked aspect of practical drug delivery is the dilution. In my view the hallmark of a well chosen dilution is that, in addition to satisfying the necessary pharmaceutical requirements, it facilitates both the mental calculation and the means of infusion and safe effective bolus delivery, particularly in urgent/emergency situations. The dilutions listed in Table 8.2 approach this ideal; they are practical and easy to remember, dosage is easy to determine without reliance on calculators or charts. Indeed, an awareness of Table 8.2 would easily have avoided the calculation error described recently by de Wildt et al. (2007), associated with setting up a noradrenaline infusion.

Table 8.2: Single strength dilutions (adults, 70 kg): start infusion at 5 mls/hr and titrate in increments of 2 mls/hr. When bolusing adrenaline, noradrenaline or isoprenaline start with 0 1–0 2 mls, titrating amount to effect (approximate bolus dose is · · 1–2 mins worth of current infusion). Drug Dilution (in saline) Bolus Infusion Dopamine 3 kg 1–10 mls/hr × mg in 50 mls 0 1–0 2 ml Dobutamine 1 · · (1–10 µg/kg/min) GTN 3 kg 1–10 mls/hr × mg in 50 mls 0 1–0 2 ml SNP · · (0 1–1 µg/kg/min) 10 · Adrenaline 3 kg 1–40 mls/hr Noradrenaline × mg in 50 mls 0 1–1 ml · (0 01–0 4 µg/kg/min) Isoprenaline 100 · ·

The entries in Table 8.2 are based on the following rule, which is a simpliﬁed and more practical form of that described by Sellick (1985), namely: for a patient weighing W kg, then diluting 3 W mg of any drug in 50 mls yields a solution for which 1 ml/hr is equivalent to 1 µg/kg/min.× When initiating an infusion, use the ‘single strength’ concentration listed in Table 8.2 (adults), and start at a rate of approximately 5 ml/hr, using boluses (see Section 8.1.2) as necessary. If the patient’s condition later requires increasingly large infusion rates, CHAPTER 8. DRUGS RWD Nickalls 

then higher concentrations (e.g., double strength, quadruple strength etc) can be used instead to avoid volume overload. If the patient is ‘obviously’ septic then start with a ‘double-strength’ dilution. A useful rule-of-thumb is to increase the infusion rate in steps of about 20%, but to decrease it in smaller steps (e.g., 10%). Although 50 ml syringe-drivers are generally used in the operating theatres, in an ITU however, where the infusions often run for long periods of time, it is generally more convenient to use larger volumes (e.g., 100 ml or 250 ml bags) in conjunction with the usual ITU infusion-delivery systems.

Example 1 A 70 kg patient requires a dobutamine infusion. The dobutamine entry in Table 8.2, shows that diluting 210 mg (3 70) in 50 ml 5% dextrose gives a concentration for which 1 ml/hr is equivalent to 1 µg/kg/min.× Start the infusion at 5 mls/hr.

Example 2 A 30 kg patient requires a GTN infusion. The GTN entry in Table 8.2, shows that diluting 9 mg (3 30/10) in 50 ml 5% dextrose gives a concentration for which 1 ml/hr is equivalent to 0 1 µg/kg/min.× Start the infusion at 5 mls/hr. · 8.1.2 Bolus dosage In emergency situations it is sometimes necessary to give IV bolus doses of these drugs (typically for GTN, adrenaline, noradrenaline). Consequently, it is very important that the dilution of the maintenance infusion used should simplify this, i.e., allow an IV bolus to be given manually and quickly using a syringe, so as not to be dependent on the electronic delivery system which can sometimes fail. An important ‘feature’ of the ‘single strength’ dilutions shown in Table 8.2 is that they facilitate the manual administration of appropriate bolus doses, quickly, safely and easily, typically using a 1 ml syringe (see examples below). I have found empirically that an appropriate initial bolus dose is a volume roughly equivalent to 1–2 minutes worth of the current maintenance infusion (depending on the severity of the problem). In practice the 1-minute bolus volume is easily calculated since an infusion rate of 6 ml/hr is equivalent to 0 1 ml/min; a maintenance infusion rate of R ml/hr is therefore equivalent to 0 1 R/6 ml· in one minute. For example, a 1-minute bolus volume for an infusion running· × at 12 mls/hr is 0 1 12/6 = 0 2 ml. In general the bolus volume can be easily and conveniently delivered· × using a 1 ml· syringe—always readily available on any ward. If the effect of the initial bolus is inadequate, sequentially double the bolus volume until a therapeutic bolus volume is found. CHAPTER 8. DRUGS RWD Nickalls 

8.1.3 Noradrenaline Example 1 Consider a 70 kg routine surgical patient requiring a noradrenaline infusion to counteract the effects of an epidural (typical requirement: single strength noradrenaline running at 2–8 mls/hr). 3 70 Step 1: Dilute 100× mg noradrenaline into 50 mls saline, (i.e., approximately 2 mg in 50 mls), and start the infusion at 5 mls/hr (equivalent to 0 05 µg/kg/min). Remember to include a three-way tap and a filled labelled 1 ml syringe,· and connect the infusion to the central-line port as a separate dedicated infusion. Step 2: Now fill the central-line deadspace cautiously, using 0 1–0 2 ml increments, until a bolus results in a transient rise in blood pressure. Then titrate· the· infusion using increments of about 2–4 mls/hr to obtain a suitable blood pressure, using small boluses via a 1 ml syringe as necessary to gain control. If the patient is significantly ‘septic’ then the infusion rate may well need to be increased, up to 50 mls/hr as necessary.2 A useful rule-of-thumb is to increase the infusion rate in steps of 20%, but to decrease it in steps of only 10%. Notes: If there is occasion to rescue a low BP of, say, 60–70 mm Hg, then a bolus of approximately 1–2 mins worth of the infusion will be an appropriate first choice test dose. For example, if the current infusion rate is 6 mls/hr then consider a test bolus of about 0 1–0 2 mls (since an infusion of 6 mls/hr is equivalent to 0 1 ml/min). · · · Example 2 Consider a 70 kg septic ITU patient on double-strength noradrenaline at 12 mls/hr, and suppose you are now called because the infusion has suddenly stopped, and the blood pressure is falling. This amount of noradrenaline is not unusual in the ITU—even the use of ‘quad’ strength is not uncommon. However, what is not widely appreciated is that if a ‘high-dose’ noradrenaline infusion stops suddenly (e.g., battery failure; line occlusion; bag/syringe empty etc.) the blood pressure fall will be rapid and profound—for example, falling to about 40–50 mmHg within 1 minute or so—and so this problem constitutes a significant emergency and must be addressed immediately. The essence of the problem, therefore, is how to administer 2 minutes worth of noradrenaline to the patient within less than 1 minute from a standing start. Step 1: Note the infusion rate:— 12 mls/hr in this case. Step 2: Divide the current infusion rate by 6 to determine the number of 0 1 ml units the patient would normally be receiving per minute 3 (this is the minimum bolus· volume).

2If large infusion ﬂow rates become necessary, then consider using twice the concentration (or more) with an appropriately reduced rate (one can happily use a ‘single’ strength dilution up to 50 mls/hr or so in a theatre setting). 3An infusion of 6 mls/hr is equivalent to 0 1 mls/min. · CHAPTER 8. DRUGS RWD Nickalls 

Thus, in this example we have 12/6 = 2, and so the ‘1-minute’ bolus volume is 2 0 1 mls = 0 2 mls. × · ·Step 3: Fill a 1 ml syringe directly from the infusion bag/reservoir/pump and inject 2 mins worth of noradrenaline infusion as a bolus—0 4 ml in this case (2 0 2)—down a separate 4 CVP/IV line and flush it in with 10 mls saline.· If there is already× · significant bradycardia, then atropine and temporary cardiac massage may also be necessary to help the drug get around. Titrate against the blood pressure, approximately 0 2 mls/min, as necessary, until the original infusion problem is fixed and ‘up and running’· again. Notes: In this particular setting, since the bolus volume is so small and a rapid response is required, the bolus must be flushed in with, say, 10–20 mls saline, in order to guarantee that the bolus is delivered into the circulation (i.e., so the drug cannot inadvertently remain within the CVP line). Consequently, a drug-free CVP-line must be used, and if any uncertainty exists, then give the bolus (initially at least) into a peripheral vein. This scenario occurs not infrequently, particularly in patients returning from theatre with their noradrenaline syringe driver on ‘empty’. You then have to sort out the severe hypotension and maintain an adequate blood pressure manually for about 5 mins or so while the nurses set up a new noradrenaline infusion. Fortunately, when a syringe driver alarms and stops there are usually several mls left in the syringe/system which can be used to fill your 1 ml syringe.

Example 3 Postoperative use of noradrenaline in patients with a history of hypertension. A patient with a long history of hypertension requiring quadruple drug antihypertensive therapy, was admitted postoperatively to ITU (following a nephrectomy; preop creatinine 150), with a blood pressure of 110–120 mmHg and poor urine output. From the notes it was clear that her usual blood pressure was approximately 160–170 mmHg, and so a CVP line was inserted and noradrenaline used to push the blood pressure up to 160 mmHg, with the effect that her urine output increased signiﬁcantly and her creatinine stabilised out at 160–170. The noradrenaline was weaned down over about 4 days (during which her pre-op antihypertensive drugs wore off) by which time her blood pressure stabilised at about 160 mmHg and she was returned to the ward. Her normal antihypertensive therapy was then gradually re-introduced.

8.1.4 References

• Aantaa R and Jalonen J (2006). Perioperative use of α2-adrenoceptor agonists and the cardiac patient. European Journal of Anaesthesiology; 23, 361–372. [clonidine and dexmedetomidate]

4Avoid using the existing noradrenaline CVP line, since you need to guarantee that (a) only the bolus dose is given, and (b) it is delivered into the circulation—you can not ﬂush the bolus with saline down the existing noradrenaline infusion line. Much safer to give it initially via a separate line, until you have control of the blood pressure. CHAPTER 8. DRUGS RWD Nickalls 

• Bellomo R and Giantomasso Di (2001). Noradrenaline and the kidney; friends or foes? Critical Care; 5, 294–298. • Cooper DW (2005). Ephedrine, phenylephrine and fetal acidosis. Anaesthesia; 60, 1237–1238. [10 refs]

• de Wildt SM, Verzijden R, van den Anker JN and de Hoog M (2007). Information technology cannot guarantee patient safety. British Medical Journal; 334, 851–852. [highlights a recent drug-infusion calculation error generated by a palm-computer medical drug program]

• Gambling DR and McLaughin KR (2010). Ephedrine and phenylephrine use during Cesarean delivery. Anesthesiology; 112, 1287–1288. • Kam PCA, Williams S and Yoong FFY (2004). Vasopressin and terlipressin: pharmacology and its clinical relevance. Anaesthesia; 59, 993–1001 [Review article] • Lee R, Giantomasso Di, May E and Bellomo R (2004). Vasoactive drugs and the kidney. Best Practice & Research Clinical Anaesthesia; 18, 53–74. • O’Donnell A (2006). Drug formulary. In: Allman KG, Wilson IH (Eds.) Oxford Handbook of Anaesthesia. 2nd. ed. pp. 1105–1165. • Roth JV (2006). The use of vasopressin bolus to treat refractory hypotension secondary to reperfusion during orthotopic liver transplantation. Anesthesia & Analgesia; 103 (July), 261. [6 refs] [Used an infusion of vasopressin 4 U/h, plus two boluses of 0 4 U, in a 83 Kg man relatively refractory to noradrenaline (20 mls/hr of ‘single-strength’· noradrenaline).] • Sellick BC (1985). The calculation of infusion rates. Anaesthesia; 40, 599.

• Smiley RM (2009). Burden of proof. Anesthesiology; 111, 470–472. [Editorial regarding ephedrine and phenylephrine in Cesarean section] • Sun Q et al. (2003). Low-dose vasopressin in the treatment of septic shock in the sheep. Am. J. Respir. Crit. Care Med.; 168, 481–486. [used 1 2 U/hr; good introduction and discussion; 44 refs] ·

• Zaritsky AL and Chernow B (1988). Catecholamines and other inotropes. In: Chernow B (Ed.) The pharmacologic approach to the critically ill patient, Chapter 31, (pp. 584–602). CHAPTER 8. DRUGS RWD Nickalls 

8.2 Somatostatin analogues & carcinoid

An good overview with useful references is presented by Mason (2001).

8.2.1 Octreotide Sandostatin: 1ml ampoule; three concentrations available: 50/100/200 µg/ml Octreotide is a synthetic analogue of the hypothalamic release-inhibiting hormone somatostatin (BNF), and is a key drug in the management of patients with carcinoid syndrome (Farling and Durairaju 2004; Vaughan and Brunner 1997; Battershill PE and Clissold SP 1989). It is used to counteract serotonin (5HT) and kinin activity and to gain full control of symptoms (subcutaneously (adults): initially 50 µg 1–2 times/day increasing to 200 µg 3 times/day). Octreotide is increasingly being used in the treatment of congenital and postoperative chylothorax (Roehr CC, Jung A, Proquitte´ H et al. 2006).

8.2.2 Ketanserin

Ketanserin is a selective antagonist of anti-5HT2, the α1-adrenoreceptor, and the H1- histamine receptor (Koopmans et al. 2005; Hughes and Hodkinson 1989). Ketanserin reduces portal pressure in animals (Chernow 1988). A 10 mg bolus IV (adults) has been used successfully in carcinoid crisis to block mediators (Koopmans et al. 2005, Hughes and Hodkinson 1989). Alternatively (adults), ketanserin 10 mg given over 3 mins followed by an infusion of 3 mg/hr is suggested by Mason (2001), Fischler et al. (1983), Hughes and Hodkinson (1989).

8.2.3 Carcinoid tumours Carcinoid (neuroendocrine) tumours have their origin in the endocrine argentafﬁne cells of the small bowel mucosa, which are part of the so-called APUD family (Amine content, Precursor Uptake, and Decarboxylation). Carcinoid is characterised biochemically by an increased urinary excretion of 5-hydroxyindole-acetic acid (5-HIAA; Mol wt 191), the normal range being 10–47 µMol/24 hrs (1 9–8 9 mg/24 hrs). A range of peptides, kinins and prostaglandins· · can be secreted, including kallikrein, bradykinin, serotonin (5HT), histamine, and substance-P. Less commonly secreted are insulin, ACTH, MSH, gastrin and glucagon. The carcinoid syndrome symptoms of diarrhoea, sedation, hypertension are thought to be due to serotonin; ﬂushing, hypotension and bronchospasm are thought to be due to bradykinin (Mason and Steane 1976).

8.2.4 Anaesthesia for bronchial carcinoid resection The anaesthetic management of such patients consists primarily of (a) using the drug octreotide for preoperative symptom control (2 days–2 weeks) and also as part of the premedication regimen, (b) avoiding drugs which liberate histamine (e.g., atracurium, CHAPTER 8. DRUGS RWD Nickalls 

morphine), (c) using small boluses of octreotide (adults: 10–20 µg) as necessary to counteract symptomatic episodes (flushing, hypotension, bronchospasm). Ketanserin (adults: 10 mg bolus IV) 5 has been used successfully in carcinoid crisis to block mediators (Koop- mans et al. 2005, Hughes and Hodkinson 1989). Steroids are often used perioperatively. Bradykinin may be the key mediator of hypotension in carcinoid syndrome (Veall et al. 1994). Preoperative control of symptoms: Octreotide is typically given subcutaneously in doses (adults) of 50–200 µg 8-hrly. Premedication: Octreotide 50–100 µg subcutaneously 1 hr preoperatively (adults). Induction: Insert the arterial line under local prior to induction. Try to avoid the use of rigid bronchoscopy by the surgeons on induction in order to minimise airway stimulation— suggest they consider flexible bronchoscopy via a single-lumen tube if necessary. Intra-operatively (adults): Use octreotide intravenously as required to control exac- erbations of bronchospasm, hypotension with flushing, and bradycardia (100 µg diluted in 10–20 mls saline). Titrate using small boluses of approximately 10–20 µg. Bradycardia associated with heart-block has been reported following a 100 µg bolus (Dilger et al. 2004). Acute hypertension may be due to serotonin (5HT) (blocked by ketanserin), while acute hypotension may be due to bradykinin (blocked by octreotide). Have a syringe of adrenaline (1/10,000) 6 immediately available to treat episodes of profound bradycardia or asystolic arrest Consider ondansetron (give slowly 7) for its anti-5HT activity (Wilde and Markham 1996). Consider using chlorpheniramine (anti-H1) and ranitidine (anti-H2) (Vaughan, Howard and Brunner 2000, Mason and Steane 1976). Monitor blood glucose (carcinoid tumours may secrete insulin or glucagon). Epidural bupivicaine + fentanyl is fine. The vasopressors of choice in carcinoid surgery are most probably phenylephrine, metaraminol, and also methoxamine (not currently available), since they are not catecholamines 8 (Koopmans et al. 2005). However, I have used a noradrenaline infusion in carcinoid cases on several occasions uneventfully.

Example of intraoperative hypotension Figure 8.1 shows an episode of extreme hypotension during a thoracic carcinoid resection. During this operation there were two such episodes (one cardiac standstill) which responded rapidly to open cardiac massage, adrenaline (2 ml of 1/10,000) and 20 µg octreotide via the CVP line. Although a noradrenaline infusion was being used at the time (to counteract the epidural), each of these episodes appeared to be related to surgical manipulation; no noradrenaline boluses were given at any stage.

5Alternatively ketanserin 10 mg over 3 mins followed by an infusion of 3 mg/hr (Mason 2001). 61 mg in 10 mls saline. 7See letter by Cherian and Maguire 2005. 8Since o dihydroxybenzine is called catechol, sympathomimetic amines having the same OH-substitutions in the benzine− ring (i.e., in both the 3- and 4- positions) are termed catecholamines (e.g., dopamine, dobutamine, noradrenaline, adrenaline, isoprenaline). CHAPTER 8. DRUGS RWD Nickalls 

ANÆSTHESIA RECORD page 16/33 300

eeee eeee e e e e 250 e e ee e e e e ee ee 200 e e eee ee ee ee e 150 ee ee e ee inv BP ee ◦ ee NIBP 2 e eee rrrr r cc cc 100 e e r r r c c cc – e e e e r r ccr r r c HR• • eee eeeeeee eeeee ee e cr r rrr rrrrrr rrr r r r cc cc c ecg c r cc c r c r c c c HRoxim• c r r r r rrr rrr crrr cccr crrrrrrrr crrrrcc cr r e rr r rrrrrrr rrrr c cr cr crrrrrrrrrrrrrrrrrr rrrr 50 rrrrrr rrr r rrr rrrrrrrrr rrrrrrrrrrrrrrrrr rrr r r c cc cc c cc r r c cccc cc c cc c cc cc cc cc r err e cc cc c c e r ec c cc r r ee 20 c e eeeer ec r c r c CVP — c cc cc c cc 0 18:24 18:25 18:26 18:27 18:28 18:29 18:30 100 c ccc cccc c ccc ccccc ccccccccccc c cc cc c cc c cc c cc cc ccc cc ccc cccc ccc cc cc cccc cccc cc SAT cc c c c cc cc cc c cc c ◦ 90 FI O2 • 80 r r r r r 18:24 18:25 18:26 18:27 18:28 18:29 r r rr18:30r 70 N2O 2 rr r r r r r rr r 50 r r rr r rrrrrrrrrr r r rr rrrrrr rr rrrrrrrrrrr rrrrr rr r r FI O2 • 30 Pplateau◦ c c c c c cc cc c c cc cc cc c c c cc c c cc c c cc cccc c 10 ccccc c ccc18:24c c cc cc c cc cc c18:25cc cc c c c cc18:26c cc c cc 18:27c c c c18:28c c cc c c 18:29c c c c c18:30cc 10 8 33 333 3333333333333333333333333333333333333333333333 6 333333333333333333333333 33 3 3 ETCO2 333333333 4 ⋄ 2 18:24 18:25 18:26 18:27 18:28 18:29 18:30 20 1000 • 15 750 2 TVexp 22222222222222222222222222222 2222222 2 2222222222222222222222222222222222222222210222 500 rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr2 22222 2 rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr RR 5 250 • 0 0 18:24 18:25 18:26 18:27 18:28 18:29 18:30 4 ... 3 VAPinsp — 2 VAPexp 3333333333333333333333333333333333333333 333333333333333333333333333333333333333333333333 1 3 MACage 0 18:24 18:25 18:26 18:27 18:28 18:29 18:30

c Nickalls RWD, Dales S & Nice AK 1994–2011: Xenon5 ANÆSTHESIARECORDSYSTEM Linux

EMAIL:[email protected] [www.nickalls.org] Figure 8.1: Anaesthetic record during a thoracic carcinoid resection in an adult, showing an episode of bradycardia and extreme hypotension which responded to cardiac massage, bolus of adrenaline (2 ml 1/10,000) and 20 µg octreotide—see text. Notice the transient reduction in ETCO2 due to low cardiac output associated with the period of hypotension. The patient made a full and uneventful recovery. Datex AS/3 monitor; data points at 5 sec intervals; BP, NIBP, CVP mmHg;

Pplateau cm H2O; TV mls; SAT, FIO2 , ETCO2 ,FIN2O, MACage, VAP (sevoﬂurane) %. CHAPTER 8. DRUGS RWD Nickalls 

8.2.5 References • Allman KG and Wilson IH (Eds.) (2006). Oxford Handbook of Anaesthesia. 2nd. ed., [APUDomas and anaesthesia for carcinoid (pp. 172–174)]

• Battershill PE and Clissold SP (1989). Octreotide: a review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in conditions associated with excessive peptide secretion. Drugs; 38, 658–702.

• Carcinoid Cancer Foundation (http://www.carcinoid.org/): This web site is mainly for patients and has lots of general information. However, it also has a good medical section (http://www.carcinoid.org/content/medical-reviews/) which has several useful articles. • Cherian A and Maguire M (2005). Transient blindness following intravenous ondansetron. Anaesthesia; 60, 938–939. [advise slow IV injection; 5HT3 and 5HT3A receptors are involved in modulation of retinal signals] • Chernow B [Ed.] (1988). The pharmacologic approach to the critically ill patient, 2nd ed. (Williams & Wilkins, Baltimore, USA). 336–337. • Cortinez LI (2000). Refractory hypotension during carcinoid resection. Anaesthesia; 55, 505–506. [see also: Vaughan DJ, Howard JM and Brunner MD 2000]

• Dery R (1971). Theoretical and clinical considerations in anaesthesia for secreting carcinoid tumours. Can. Anaesth. Soc. J.; 18, 245–263. [cited from Vaughan DJ, Howard JM and Brunner MD 2000] • Dilger JA, Rho EH, Que FG, Sprung J (2004). Octreotide-induced bradycardia and heart block during surgical resection of a bronchial carcinoid tumor. Anaesthesia and Analgesia; 98, 318–320. [this event followed a 100 µg bolus] • Farling PA and Durairaju AK (2004). Remifentanil and anaesthesia for carcinoid syndrome. Br. J. Anaesth.; 92, 893–895. [excellent review] • Fischler M, Dentan M, Westernam MN et al. (1983). Prophylactic use of ketanserin in a patient with carcinoid syndrome. Br. J. Anaesth.; 55, 920. [cited from Mason 2001] • Hughes EW and Hodkinson BP (1989). Carcinoid syndrome: the combined use of ketanserin and octreotide in the management of an acute crisis during anaesthesia. Anaesthesia and Intensive Care; 17, 367–370. [cited from Koopmans et al., 2005]

• Keens SJ, Desmond NJ and Utting JE (1986). Carcinoid syndrome with myasthenia gravis. Anaesthesia, 41, 404–407. CHAPTER 8. DRUGS RWD Nickalls 

• Kema IP, de Vries EG and Muskiet FA (2000). Clinical chemistry of serotonin and metabolites. J. Chromatogr. Biomed. Sci. Appl.; 747, 33–48. [cited from Koopmans et al., 2005] • Kinney MA, Warner ME, Nagorney DM et al. (2001). Perianaesthetic risks and outcomes of abdominal surgery for metastatic carcinoid tumours. Br. J. Anaesth.; 87, 447–452. • Koopmans KP, Brouwers AH, De Hooge MN et al.(2005). Carcinoid crisis after injection of 6-18F-Fluorodihydroxyphenylalanine [18F-DOPA] in a patient with metastatic carcinoid. The Journal of Nuclear Medicine; 46, 1240–1243.

• Kvols LK, Martin JK, Marsh HM et al. (1985). Rapid reversal of carcinoid crisis with a somatostatin analogue [letter]. N. Engl. J. Med.; 313, 1229–1230. [cited from Koopmans et al., 2005] • Mason R (2001). Anaesthesia databook: a perioperative and peripartum manual. 3rd ed. (see section on Carcinoid syndrome). • Mason RA and Steane PA (1976). Carcinoid syndrome: its relevance to the anaesthetist. Anaesthesia, 31, 228–242. • Roehr CC, Jung A, Proquitte´ H et al. (2006). Somatostatin or octreotide as treatment options for chylothorax in young children: a systematic review. Intensive Care Med.; 32, 650–657. [56 refs] • Vaughan DJ and Brunner MD (1997). Anesthesia for patients with carcinoid syndrome. Int. Anesthesiol. Clin.; 35, 129–142. [excellent] • Vaughan DJ, Howard JM and Brunner MD (2000). Refractory hypotension during carcinoid resection. Anaesthesia; 55, 927 [letter] [see also: Cortinez 2000].

• Veall G, Peacock J, Bax N and Reilly C (1994). Review of the anaesthetic management of 21 patients undergoing laparotomy for carcinoid syndrome. Br. J. Anaesth.; 72, 335–341. [cited from Cortinez 2000] • Wilde IM and Markham A (1996). Ondansetron. A review of its pharmacology and preliminary clinical ﬁndings in novel applications. Drugs; 52, 773–794. CHAPTER 8. DRUGS RWD Nickalls 

8.3 Haemostatic drugs

Note that the hospital has a ‘major haemorrhage’ guideline. See also review by Mahdy and Webster (2004) discussing the role of agents for reducing perioperative blood loss and transfusion requirements. Consider the cell-saver. • Bombeli T and Spahn DR (2004). Updates in perioperative coagulation: physiology and management of thromboembolism and haemorrhage Br. J. Anaesth.; 93, 275– 287. [excellent review article]

• Mahdy AM and Webster NR (2004). Perioperative systemic haemostatic agents. Br. J. Anaesth.; 93, 842–858.

Recombinant factor VIIa The hospital has a Guideline for use of Factor VIIa for use in massive haemorrhage.

• Ahonen J and Jokela R (2005). Recombinant factor VIIa for life-threatening post- partum haemorrhage. Br. J. Anaesth.; 94, 592–595. • Spahn DR and Makris M (2005). Is recombinant FVIIa the magic bullet in the treatment of major bleeding? Br. J. Anaesth.; 94, 553–555. [editorial] • Welsby IJ, Monroe DM, Lawson JH and Hoffmann M (2005). Recombinant activated factor VII and the anaesthetist. [review article] Anaesthesia; 60, 1203–1212.

8.4 Remifentanil

Remifentanil (Ultiva) is an ultra short-acting narcotic, used either as a bolus or as an infusion. Remifentanil pharmacokinetics are not modiﬁed by hepatic or renal failure (Absalom and Struys 2006). Duration of action when given as a bolus is approximately 10 mins. See the excellent review by Scott and Perry (2005).

8.4.1 Bolus

Drug Dilution (in saline) Bolus dose (adults) Remifentanil (Ultiva) 1 mg/20 mls 0 5–1 5 µg/kg 1 mg ampoule (50 µg/ml) · · CHAPTER 8. DRUGS RWD Nickalls 

Induction of anaesthesia Remifentanil is an extremely useful co-induction agent for intubation and for bronchoscopy. It is very cardio-stable and reduces the propofol induction dose by about 50%. Typical co-induction dose for 70 kg adult: 70–100 µg (in 25–50 µg increments over 2 mins). Use approximately half the dose in the elderly. Watch out for (a) respiratory depression, especially in the elderly (only give during pre-oxygenation), (b) bradycardia (have atropine handy), (c) hypotension.

During anaesthesia Bradycardia seems to be most pronounced during anaesthesia with volatiles, so once anaesthesia has been established then titrate initially with 10–20 µg boluses (70 kg adult) in order to determine the effective dose.

8.4.2 Infusion For sedation and analgesia in ventilated patients in an ITU setting, the recommendation is to start at about 0 1 µg/kg/min and titrate by 20% depending on the response, as shown in the following Table.· ±

Drug Dilution (5% Dex or saline) Infusion (adults) Remifentanil 3 kg start at 10 mls/hr mg in 50 mls (Ultiva) × (0 1 µg/kg/min) 100 · For anaesthesia, any recommendation of speciﬁc ranges of MAC to supplement a remifentanil infusion should really be based on a review of the growing literature of observed MAC reductions (see: Breslin et al. 2001, Lang et al. 1996, van Delden et al. 2002). For TCI techniques see Absalom and Struys (2007). The Minto 3-compartment model (Minto, Schnider, Egan et al. 1997; Minto, Schnider and Shafer 1997) most commonly used for remifentanil, uses age and lean body mass (LBM) as co-variables, and so requires entry of weight, height and gender as well (Absalom and Struys 2007, p. 16).

8.4.3 References • Absalom AR and Struys MMRF (2007). Overview of target controlled infusions and total intravenous anaesthesia. 108 pp. (Academia Press, Ghent, Belgium; http://www.academiapress.be) ISBN 978-90-382-11077 [excellent small book sponsored by the marketing department of Carefusion, Basingstoke, RG22-4BS, Hampshire, UK; tel: +44(0)1256-388462] CHAPTER 8. DRUGS RWD Nickalls 

• Breslin D, Reid JE, Mirakhur RK, Hayes AK and McBrien ME (2001). Sevoflurane- nitrous oxide anaesthesia supplemented with remifentanil: effect on recovery and cognitive function. Anaesthesia; 56, 114–119. This article attempts to determine the appropriate remifentanil infusion rate associated with sevoflurane at 1 5, 1 0 and 0 5 MAC. They found that a remifentanil infusion of 0 34 (range 0 20–·0 49· µg/kg/min)· requires a MAC of 0 5 in a population of mean age· 30 years and· mean· BMI 25 1 for operations of mean· duration 57 mins. · • Lang E, Kapila A, Shlugman D, Hoke JF, Sebel PS and Glass PSA (1996). Reduction of isoflurane minimal alveolar concentration by remifentanil. Anesthesiology; 85, 721–728. Their conclusion (majority of patients in the age-range 31–55) was that isoflurane (in oxygen only) concentrations of 0 4–0 5 % (i.e., 0 4 MAC40 approx from my charts) required a remifentanil infusion rate· of· 0 15–0 3 µ·g/kg/min for adequate anaesthesia (plasma level of 4–8 ng/ml). · ·

• Minto, CF, Schnider TW, Egan TD et al. (1997). Inﬂuence of age and gender on the pharmacokinetics and pharmacodynamics of remifentanil. I. Model development. Anaesthesiology; 86, 10–23. • Minto, CF, Schnider TW and Shafer SL (1997). Pharmacokinetics and pharmacodynamics of remifentanil. II. Model application. Anaesthesiology; 86, 24–33.

• Purugganan RV (2008). Intravenous anesthesia for thoracic procedures. Current Opinion in Anaesthesiology; 21, 1–7. • Scott LJ and Perry CM (2005). Remifentanil. A review of its use during the induction and maintenance of general anaesthesia. Drugs; 65, 1793–1823. [excellent]

• van Delden PG, Houweling PL, Bencini AF, Ephraim EP, Frietman RC, van Niekert J, van Stolk MA, Verheijen R, Wajer OJ, Mulder PGH (2002). Remifentanil– sevoflurane anaesthesia for laparoscopic cholecystectomy: comparison of three dose regimens. Anaesthesia; 57, 212–7. This article determined the appropriate remifentanil infusion rate associated with sevoflurane (with no nitrous oxide) at 1 2, 0 8 and 0 4 MAC. They found that a remifentanil infusion of 0 23 (range 0 12·–0 73· µg/kg/min)· requires a MAC of 0 8 in a population of mean age· 47 years.· Their· conclusion was that the optimum· combination (for anaesthesia quality and recovery rate) was sevoflurane ET 1 24 % 9 · (i.e., MAC47 = 0 7 approx from my charts ) and remifentanil 0 23 µg/kg/min (I have converted their· µg/kg/hr to µg/kg/min). ·

9See Figures 9.1, 9.2, 9.3. 9 Supporting technologies

ERE we address some of the supporting technologies associated with thoracic anaesthesia. The motivation is historical—to highlight some of the key references H and see how discoveries were made.1 Since our subject is thoracic anaesthesia the recent historical overview by Brodsky 2 (2005) is an excellent starting point. Unfortunately the historical background of medical discoveries tends to be insufficiently emphasised, but time spent reading original papers and early documentation is usually well rewarded, often revealing not only scientists with extreme focus and mental tenacity but also the occasional hand of serendipity.3 Two insights are commonly cited as influencing discovery and subsequent innovative development. The first is awareness of the problem, immortalised by Louis Pasteur (1822– 1895) in the succinct but misquoted phrase Chance favours the prepared mind.4 The second is appreciating the significance of a discovery. For example, although Crawford Long (1815–1878) was apparently the first person to use ether for a surgical operation, we really owe the initial development of clinical anaesthesia to William Morton 56 (1819–1868) who appreciated its value to humanity, and to John Snow (1813–1858) who laid the scientific foundations of inhalational anaesthesia.7 1See the memorable September 2002 issue of the ASA Newsletter (http://www.asahq.org/) on the history of monitoring. 2Brodsky JB (2005). The evolution of thoracic anesthesia. Thoracic Surgery Clinics; 15, 1–10. 3See accounts by Comroe (1977), Swazey and Reeds (1978) and Watson (1968) in Section 1.2 (History). 4The full sentence actually used by Pasteur in his inaugural address (1854) as the professor of chemistry at the Faculte´ des Sciences at Lille, was In the field of observation, chance only favours those minds which have been prepared. (Mackay A (1977). The harvest of a quiet eye; a selection of scientific quotations. Institute of Physics, London; ISBN 0-85498-031-8. page 116.) 5MacQuitty B (1969). The battle for oblivion: the discovery of anaesthesia. (GG Harrap & Co. Ltd., London). 6It now appears that there were in fact several other people experimenting with ether at that time (see [Section 9.4.5] Stone, Meyer and Alston 2010). 7See more on John Snow in Section 9.4.1.

141 CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

9.1 Serendipity

The word serendipity is often used in the context of discovery and innovation; its original usage was very speciﬁc—discovering, quite by accident, something that you were not looking for (Remer 1965). The word is ascribed to Horace Walpole (1717–1797), who used it in 1754 in a letter 8 to Horace Mann, then living in Florence (Toynbee 1903; Remer 1965, Boyle 2000).

This discovery indeed is almost of that kind I call serendipity, a very expressive word, which as I have nothing better to tell you, I shall endeavour to explain to you: you will understand it better by the derivation than by the deﬁnition. I once read a silly fairy tale, called The three princes of serendip:9 as their highnesses travelled, they were always making discoveries, by accidents and sagacity, of things which they were not in quest of: for instance, one of them discovered that a mule 10 blind of the right eye had travelled the same road lately, because the grass was eaten only on the left side, where it was worse than on the right—now do you understand serendipity? One of the most remarkable instances of this accidental sagacity (for you must observe that no discovery of a thing you are looking for, comes under this description) was of my Lord Shaftsbury, who happening to dine at Lord Chancellor Clarendon’s, found out the marriage of the Duke of York and Mrs Hyde, by the respect with which her mother treated her at table. Horace Walpole — January 28, 1754 From: Toynbee (1903)

The animal in the original story was actually a camel. The relevant extract from the 1964 English translation of the 1557 Italian version (Boyle 2000), runs as follows.

Misfortune befalls the princes when a camel driver stops them on the road and asks them if they have seen one of his camels. Although they have not, they have noticed signs that suggest a camel has passed along the road. Ever ready to dazzle with their wit and sagacity, the princes mystify the camel driver by asking him if the lost camel is blind in one eye, missing a tooth and lame. The camel driver, impressed by the accuracy of the description, immediately hurries off in pursuit of the animal. After a fruitless search, and feeling deceived, he returns to the princes, who reassure him by supplying further information. The camel, they say, carried a load of butter on one side and honey on the other, and was ridden by a pregnant woman. Concluding that the princes have stolen the camel, the driver has them imprisoned. It is only after the driver’s neighbour ﬁnds the camel that they are released. The princes are brought before the Emperor Beramo, who asks them how they could give such an accurate description of a camel they have never seen. It is clear from the princes’ reply that they had brilliantly interpreted the scant evidence observed along the road. 8Letter dated 28 January, 1754—see Toynbee (1903). 9Sri Lanka. 10A camel in the English version. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

As the grass had been eaten on one side of the road where it was less verdant, the princes deduced that the camel was blind on the other side. Because there were lumps of chewed grass on the road the size of a camel’s tooth, presumably they had fallen through the gap left by a missing tooth. The tracks showed the prints of only three feet, the fourth being dragged, indicating that the animal was lame. That butter was carried on one side of the camel and honey on the other was clear because ants had been attracted to melted butter on one side of the road and ﬂies to spilled honey on the other. Boyle (2000)

• Boyle R (2000). The three princes of Serendip. http://livingheritage.org/ three_princes.htm

• Remer TG (1965). Serendipity and the three princes: from the PEREGRINAGGIO of 1557 (University of Oklahoma Press, Norman, Oaklahoma, USA). [includes an English translation of the 1557 Peregrinaggio edition] • Toynbee P (1903). Letters of Horace Walpole; arranged by Mrs. Paget Toynbee. (The Clarenden Press, Oxford, UK). See letter dated: 28 January, 1754. Walpole’s letters (Ed. P Cunningham, 4 vols) are available on the Project Gutenberg website (http://www.gutenberg.org/). For the letter of 28 January 1754 (to Horace Mann) see letter 90, Volume 2 (1749–1759), pages 203–205:

9.2 Tuohy needle with Huber point and Lee markings

Not only is the modern epidural needle a fusion of three primary ideas, but it actually started life as spinal needle. Of the many designs which have been developed few have endured (see the excellent review by Frolich¨ et al. 2001). Edward Boyce Tuohy (1908–1959) was an anaesthetist at the Mayo Clinic (Rochester, Minnesota, USA), interested in continuous spinal anaesthesia (Maltby 2002). Although this technique was ﬁrst described by Henry Dean in 1906, it was mainly developed during the 1940s by William Lemmon (Maltby, 2002). However Lemmon’s technique was far from ideal since it required the needle to remain in position (tip in the CSF) during anaesthesia in order to allow intermittent top-ups as required. Tuohy’s idea was to develop a method of introducing a catheter into the lumbar CSF space via a spinal needle to facilitate continuous spinal anaesthesia—the needle itself could then be removed once the catheter was in place. Continuous caudal anaesthesia via a caudal catheter was already fairly widely used, and lumbar subarachnoid catheters were also sometimes used for drainage in meningitis. In 1944 Tuohy described this technique using an ordinary 15-gauge spinal needle (Maltby 2002), and only later, in 1945, did he decide to incorporate the Huber point (designed by Ralph L Huber (1890–1953) and made by Becton Dickinson) taking advantage of its lateral opening which allowed the catheter to be directed sideways into the CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

space (Tuohy 1945). In 1949, both MM Curbelo and Charles Flowers described using the Tuohy needle for epidural anaesthesia. Tuohy was later appointed professor of anaesthesia at the Georgetown Medical Centre in Washington, DC. Finally, we owe the 1 cm markings on the standard Tuohy needle to the English anaesthetist John Alfred Lee (1906–1989). He added them so that anaesthetists would know fairly accurately the depth of the needle tip, and hoped that this small reﬁnement might reduce the number of dural taps (Lee 1960; Maltby 2002).

• Eldor J (1995). Huber needle and Tuohy catheter. Regional Anesthesia; 20, 252–253 [cited from Maltby 2002] • Frolich¨ MA and Caton D (2001). Pioneers in epidural needle design. Anesthesia and Analgesia; 93, 215–220.

• Lee JA (1960). Specially marked needle to facilitate epidural block. Anaesthesia; 15, 186. [cited from Maltby 2002] • Maltby JR (2002). Notable names in anaesthesia. (The Royal Society of Medicine Press Limited, London). [JA Lee (pp. 114–116); EB Tuohy (pp. 216–218)] • Schorr MR (1966). Needles: some points to think about Part II. Anesthesia and Analgesia; 45, 514–519 [cited from Maltby 2002] • Tuohy EB (1945). Continuous spinal anesthesia: a new method utilizing a ureteral catheter. Surgical Clinics of North America; 25, 834–840 [cited from Maltby 2002]

9.3 Pulse oximetry

For a detailed review of the long and and fascinating history of blood gases, oximetry and pulse oximetry see Severinghaus (2002; 1986) and Severinghaus and Astrup (1987). The ﬁrst practical oximeter was the eight-wavelength ear-oximeter developed in 1964 by Robert Shaw and subsequently marketed by Hewlett-Packard in 1970 (Moyle 1994). In 1971 Takuo Aoyagi (1936–), a Japanese biomedical engineer at the Nihon Kohden Corporation (Tokyo), used the pulsatility of the absorption signal to separate arterial and tissue absorption and determine arterial saturation. Severinghaus describes it thus:

Takuo Aoyagi . . . attempted to eliminate arterial pulsatile ‘noise’ in his earpiece dye dilution curves by subtracting infra-red signals. He observed that the compensated noise varied with oxygen saturation and realised that it might be used to compute the arterial oxygen saturation. Severinghaus (1989) CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

The first commercial pulse oximeter appeared in 1970 (Moyle 1994), and in 1982 the Stanford anaesthetist William New (1942–), with Jack Lloyd and engineer Jim Coren- ham, founded Nellcor 11 Incorporated to mass-produce clinically useful pulse-oximeters (Rendall-Baker and Bause 2002). If a finger pulse-oximeter fails owing to significant peripheral vasoconstriction, then an ear-probe will usually be satisfactory. Alternatively, a digital nerve block may help (Erasmus 2003).

• Astrup PB and Severinghaus JW (1986). History of blood gases, acids and bases. (Munksgaard, Copenhagen). [from Severinghaus 1989] • Breathnach CS (1972). The development of blood gas analysis. Medical History; 16, 51–62. (available from http://www.ncbi.nlm.nih.gov/pmc/journals/228/) • Erasmus PD (2003). Digital block improves pulse oximetry signal in vasoconstricted patients. Anaesthesia; 58, 1033–1034. • Kofke WA (2003). An interview with John W. Severinghaus. Association of University Anesthesiologists (AUA) Update; Fall 2003 issue. http://www.auahq. org/fall03aua.pdf [an interesting 4 page article in which Severinghaus describes how he became involved in MAC, blood gases and oximetry] • Moyle JTB (1994). Pulse oximetry. (BMJ Publishing Group, London). • Pole Y (1999). Evolution of the pulse-oximeter. The History of Anaesthesia Society Proceedings; 26, 21–22.

• Rendell-Baker L and Bause GS (2002). Cardiorespiratory monitoring: a pictorial sampler. ASA Newsletter; 66, No. 9 (September) (http://www.asahq.org/) • Severinghaus JW (2002). The history of clinical oxygen monitoring. In: Eds. Diz JC, Franco A, Bacon DR, Rupreht J and Alvarez J. The History of Anesthesia. Proceedings of the Fifth International Symposium on the History of Anesthesia; Santiago, Spain, 19–23 September 2001. Excerpta Medica, International Congress Series 1242. ISBN 0-444-51293-4 (Elsevier Science). pp. 115–120. • Severinghaus JW and Astrup PB. (1987). History of blood gas analysis. International Anesthesiology Clinics; 25, no. 4, (Little, Brown & Co.., Boston, USA). [ﬁrst published as a series of articles in Journal of Clinical Monitoring in 1986]

• Severinghaus JW (1986). Historical development of oxygenation monitoring. In: Pulse Oximetry. Eds. Payne JP & Severinghaus JW, (Springer-Verlag), pp. 1–18 [covers spectroscopy, oximetry and blood gas electrodes]

11The name ‘Nellcor’ was derived from a synthesis of the surnames NEw, LLoyd, CORenham (Rendall-Baker and Bause 2002). CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Severinghaus JW and Astrup PB. (1986). History of blood gas analysis. VI. Oxime- try. Journal of Clinical Monitoring; 2, 270–288. • Severinghaus JW and Honda Y. (1987). History of blood gas analysis. VII. Pulse oximetry. Journal of Clinical Monitoring; 3, 135–138. • West JB (1998). High life; a history of high-altitude physiology and medicine. (Oxford University Press). • Yoshiya I, Shimada Y and Tanaka K (1980). Spectrophotometric monitoring of arterial oxygen saturation in the ﬁngertip. Med. Biol. Eng. Comput.; 18, 27–32. [excellent]

9.4 MAC

Ether contributes other benefits besides preventing the pain. It keeps patients still, who otherwise would not be. John Snow From: Eger (1974),12 p. 1 9.4.1 History John Snow John Snow (1813–1858) appears to have been the first person to appreciate the importance of controlling the inspired concentration of volatile anaesthetics, and within five years of William Morton’s ether demonstration 13 he had single-handedly established the scientific foundations underpinning the pharmacokinetics of volatile anaesthetics. Snow was a London-based GP with hospital connections, and had been interested for a long time in the use of inhalation agents on respiration. He initially investigated the use of carbon dioxide, and had been experimenting with inhaled ether since 1843 believing it to be a useful medicine for improving circulation. In 1846 he published an article entitled “Pathological effects of atmospheres” (Maltby 2002; Vinten-Johansen et al. 2003). Consequently, following Morton’s ether demonstration (October 16, 1846) at the Massachusetts General Hospital (Boston, USA), and the subsequent demonstration in London in December 1846, Snow found himself in the right place at the right time. Furthermore, with his interest in chemistry and recent researches into inhaled ether he also found himself to be just the right person to get involved in this new anaesthesia phenomenon. Since his GP work was not very profitable, Snow decided to take up anaesthesia. Snow was extraordinarily industrious and productive. By mid 1847 he had (a) defined and published the temperature characteristics of ether vapour (January 1947), (b) designed

12This quotation, which heads Eger’s own chapter on MAC, is from: Snow 1847 (part 4). 13William Morton (1819–1868) gave his demonstration on October 16, 1846. For an excellent account of the history and background see MacQuitty (1969). CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

an ether inhaler, (c) defined a range of clinical stages of anaesthesia (his five ‘degrees of narcotism’), and (d) performed many animal experiments with a view to determining the effects of different inspired concentrations of both ether and chloroform. Snow appreciated the significance of knowing the saturated vapour pressure, and went on to show that the amount of volatile agent required to produce anaesthesia was inversely related to its solubility in the blood. Snow published his findings in an eighteen-part series of articles in the journal London Medical Gazette during the period 1848 to 1851, entitled “On narcotism by the inhalation of vapours”. In the following extracts (all from Part–I of the series) Snow describes the effects on a mouse of a sequence of step increases in the inspired concentration of ether (from approximately 1 2 % to 4 7 %).14 Notice the detail of his observations, and how he pays particular attention· to how· well the mouse breathes (I have added a calculated ether concentration in MAC mouse at each stage to make it easier to follow his experiments).

I consider, however, that I have found a plan of determining more exactly the [required] proportion of ether and of other volatile substances present in the blood in the different degrees of narcotism. It consists of ascertaining the most diluted mixture of vapour and of air that will sufﬁce to produce any particular amount of narcotism; and is founded on the following considerations, and corroborated by its agreeing with the comparative physiological strength of the various substances. . . . The plan which I adopted to ascertain the smallest quantity of vapour, in proportion to the air, that would produce a given effect, was to weigh a small quantity of the volatile liquid in a little bottle, and introduce it into a large glass jar covered with a plate of glass; and having taken care that the resulting vapour was equally diffused through the air, to introduce an animal so small, that the jar would represent a capacious apartment for it, and wait for that period when the effects of the vapour no longer increased. . . .

Exp. 17. — Two grains of ether were put into a jar holding 200 cubic inches [1 16 %, 0 36 MAC], and the vapour diffused equally, when a tame mouse was introduced,· and allowed· to remain a quarter of an hour, but it was not appreciably affected.

Exp. 18. — Another mouse was placed in the same jar, with three grains of ether, being a grain and a half to each 100 cubic inches [1 75 %, 0 55 MAC]. In a minute and a half it was unable to stand, but continued to move· its limbs· occasionally. It remained eight minutes without becoming further affected. When taken out it was sensible to pinching, but fell over on its side in attempting to walk. In a minute and a half the effect of the ether appeared to have gone off entirely.

Exp. 19. — A white mouse in the same jar, with four grains of ether [2 33 %, 0 72 MAC], was unable to stand at the end of a minute, and at the end of another· minute· ceased to move, but continued to breath naturally, and was taken out at the end of ﬁve minutes. It moved on being pinched, began to attempt to walk at the end of a minute, and in two minutes more seemed quite recovered.

14MAC ether = 3 2 % (Eger 1974, p. 5). mouse · CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

Exp. 20. — Five grains of ether, being two and a half grains to each 100 cubic inches [2 92 %, 0 91 MAC], were diffused throughout the same jar, and a mouse put in. It became· rather· more quickly insensible than the one in the last experiment. It was allowed to remain eight minutes. It moved its foot a very little when pinched, and recovered in the course of four minutes.

Exp. 21. — A white mouse was placed in the same jar with six grains of ether [3 5 %, 1 1 MAC]. In a minute and a half it was lying insensible. At the end of three minutes· the· breathing became laborious, and accompanied by a kind of stertor. It continued in this state till taken out, at the end of seven minutes, when it was found to be totally insensible to pinching. The breathing improved at the end of a minute; it began to move at the end of three minutes; and ﬁve minutes after its removal it had recovered.

Exp. 22. — The same mouse was put into this jar on the following day, with seven grains of ether, being 3 5 grs to the 100 cubic inches [4 08 %, 1 28 MAC]. Stertorous breathing came on sooner· than before; it seemed at the· point· of death when four minutes had elapsed; and being then taken out, was longer in recovering than after the last experiment.

Exp. 23. — Two or three days afterwards the same mouse was placed in the jar, with eight grains of ether, being 4 grains to the 100 cubic inches [4 66 %, 1 46 MAC]. It became insensible in half a minute. In two minutes and a half the· breathing· became difﬁcult, and at a little more than three minutes it appeared that the breathing was about to cease, and the mouse was taken out. In a minute or two the breathing improved, and in the course of ﬁve minutes from its removal it had recovered.

. . . We ﬁnd from the eighteenth experiment, that a grain and a half of ether for each 100 cubic inches of air, is sufﬁcient to induce the second degree of narcotism in the mouse; and a grain and a half of ether make 1 9 cubic inches of vapour, of sp. gr. 2 586. 15· · Now the ether I employed boiled at 96 ◦[F]. At this temperature, consequently, its vapour would exclude the air entirely; and the ether vapour in contact with the liquid giving it off, could only be raised to 100◦ by such a pressure as would cause the boiling point of the ether to rise to that temperature. That pressure would be equal to 32 4 inches of mercury [1 082 Atm.], or 2 4 inches above the usual barometrical pressure;· and the vapour would· be condensed somewhat,· so that the space of 100 cubic inches [at 1 082 Atm.] would contain 108 cubic inches at the usual pressure [1 Atm.]. This is the quantity,· then, with which we have to compare 1 9 cubic inches, in order to ascertain the degree of saturation of the space in the air-cells· of the lungs, and also of the blood; and by calculation, as when treating of chloroform,

1 9 is to 108 as 0 0175 is to 1 · · So that we ﬁnd 0 0175 [1 75 %], or 1/57th, to be the amount of saturation of the blood by ether necessary· to produce· the second degree of narcotism; Snow (1848a)

15 F 32 C 96 ◦F = 35 5 ◦C. ( −9 = 5 ). Pure diethyl-ether boils at 34 51 ◦C (CRC Handbook of chemistry and physics; 1972). · · CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

Notice the interesting way in which Snow calculates the vapour concentration resulting 16 17 18 19 from 1 5 grains of liquid diethyl-ether in 100 cubic inches of air at 100 ◦F as 1 75 %.· My own calculation runs as follows. Since the molecular weight of diethyl-ether is· 74 12, the volume of pure ether vapour at STP occupied by 96 75 mg liquid ether (1 5 grains)· is given by 20 · · 96 75 22 4 · = 29 24cc · × 74 12 · · 21 If we now correct this volume for a temperature of 100 ◦F (37 7 ◦C) we obtain 29 24 310 7/273 = 33 3 cc. Adding this volume of pure vapour to 100· cubic inches of· air 22× (also· at 37 7 C)· gives a concentration of · ◦ 33 3 · = 0 01754 1 75 % 33 3 + (100 2 543 310 7/273) · ≡ · · × · × · However, we have made some simplifying assumptions (e.g., constant pressure and complete mixing), and since Snow only used a glass jar with a simple lid, it is likely that some of the mixture escaped from the jar before mixing was complete.23 It is clear from these extracts from Snow’s publications, that Snow was seeking the inspired concentration associated with each of his five ‘degrees of narcotism’, and that he was guided by two key principles, namely (a) to determine ‘the most diluted mixture’ which gave these effects (i.e., the minimum concentration), and (b) waiting until ‘the effect no longer increased’ (i.e., at equilibrium). Snow’s pharmacological approach of linking particular inspired concentrations of vapour to particular states or depths of anaesthesia, and then using this information to try and deliver a safer form of anaesthesia by controlling the inspired vapour concentration was, therefore, strikingly similar to our modern use of MAC.24 His experiments were carefully performed, observed, and well documented—in fact so much so that they even allow us to make a reasonably accurate estimate of MAC for the mouse. For example, Snow’s experiments 20 and 21 suggest that the inspired concentration of ether associated with 50 % movement was between 2 9 % and 3 5 %, giving an estimate close to the modern value of MAC ether for the mouse 25· of 3 2 %.· mouse · 161 grain = 64 5 mg. 17 · CH3 CH2 OCH2 CH3; molecular weight = 74 12; BP = 34 51 C · · ◦ 181 cubic inch = 2 543 = 16 38 cc. 19 · · 100 ◦F = 37 7 ◦C. 201 gm mol of· vapour occupies 22 4 L at STP. 21Note that this is roughly mouse body· temperature. 22We keep the pressure constant and assume complete mixing. 23Please email me if you improve on this analysis. 24The first paper on MAC was by Merkel and Eger (1963). The definition of MAC is as follows:– the minimum alveolar concentration, at equilibrium, and at 1 atmosphere pressure, which prevents movement in 50 % of patients to a standard surgical incision. For an excellent early overview of MAC see Chapter 1 in the timeless classic book by Eger (1974). 25Eger (1974), p. 5. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

100 years or so later in the early 1960s Eger and Severinghaus embodied Snow’s concepts in the form of MAC (Merkel and Eger 1963; Saidman and Eger 1964; Eger, Saidman, and Brandstater 1965a).

Edmond Eger In 1960 Edmond Eger joined the San Francisco Department of Anaesthesia, and became a ‘Research Fellow’ to John Severinghaus (Eger 2002, Maltby 2002). Eger and Dr Giles Merkel (Research Fellow) were given the task of deﬁning the properties of a new volatile anaesthetic agent called halopropane. Eger describes the early steps as follows.

From studies John [Severinghaus] and others had performed with carbon dioxide, we knew that measuring the end-tidal concentration of a gas gave us a handle on the arterial partial pressure for that gas. Also, the work of Kety and Schmidt indicated that the cerebral partial pressure of an inert gas should rapidly equilibrate with the partial pressure in arterial blood. So, if we measured the end-tidal concentration of halopropane and held it stable for a sufﬁcient period of time, the end-tidal concentration would give us a measure of the anesthetic partial pressure at its site of action. With that, we had the ﬁrst part of MAC. The second part was not hard to come by. . . . Movement. A categorical response, seemed just the thing . . . So we married the end-tidal concentration with movement–no movement as an index of anesthesia, and MAC was born. Everything except the name. John’s group met every Monday morning to discuss the previous week’s work and what might be done in the coming week . . . At one of these Giles and I told of our technique for determining the minimal alveolar anesthetic concentration, and John connected this to the ratio of the speed of an airplane relative to the speed of sound (a MAAC ratio). John now says it never was clear why we chose MAC rather than MAAC. I don’t remember either, except that we wanted to emphasise the word “alveolar”. Besides, voicing “MAAC” might make us sound like bleating sheep rather than anesthesiologists. The next step was to determine MAC in humans. . . . The result was the series of articles that were published in 1965 (Eger, Saidman and Brandstater 1965a, 1965b; Eger et al. 1965). Eger (2002)

John Severinghaus Severinghaus (Severinghaus 2009, Maltby 2002) recalled this episode in a recent journal interview as follows (Kofke 2003).

Dr. Eger was interested in the relative potency of anesthetics. He wanted a way to compare them numerically in terms of their alveolar concentrations at the time of establishment of a minimal level of anesthesia to permit surgery. It was clear to all that for each patient or animal, there was a critical alveolar (and thus arterial and ultimately brain) pressure of an agent that just prevented a motor response to pain. He CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

believed this would be a relatively invariant number between patients This would be the minimal alveolar anesthetic concentration. I recalled that in aviation, a similar index, Mach, was the ratio of an aircraft’s speed to the speed of sound.26 A hypersonic flight was defined, for example, as Mach 2, twice the speed of sound. I suggested the same symbol be used for the ratio of concentration of the anesthetic in the alveoli (as determined in the airway at end expiration) to that critical no-movement level, which would be defined as 1 MAC, originally MAAC. It still should be MAAC since we can’t agree on whether the single ‘A’ refers to alveolar or anesthetic or both. Kofke (2003)

William Mapleson In 1979, a far-sighted William Mapleson anticipated the increasingly central role of MAC with respect to how anaesthetists delivered a given depth of anaesthesia, as follows (see also Maltby 2002).

. . . To this end, the anaesthetist will be invited to set his ﬂows of oxygen and nitrous oxide in the normal way and then to set the brain tension of anaesthetic he requires, not in kPa or mmHg, but in total MAC units. Mapleson (1979).

More recently the clinical utility of MAC has been extended by establishing its variation with age (Mapleson, 1996), temperature (Eger 2001) and hair colour (Liem et al. 2004).

9.4.2 Age-corrected MAC Although several factors are known to be associated with altered anaesthetic requirements,27 age is the most important owing to the increasingly large age-range met with in clinical practice. While age has long been known to inﬂuence anaesthetic requirement (Gregory, Eger and Munson 1969), the exact variation of MAC with age was formalised only recently by Mapleson (1996), following a meta-analysis of the available data (see Table 9.1). In particular, Mapleson showed that semi-log plots of MAC against age (age 1 year) for all inhalational agents are linear and parallel, and hence it is probable that all≥ the inhalational agents achieve their effects by a similar mechanism. On this basis, therefore, Mapleson derived the following relationship between age and MAC from the pooled data,

0 00269(age 40) MACage = MAC40 10− · − × which expresses MAC for a given age as a function of that at 40 years (MAC40). The computed real-time MAC as displayed by the Datex AS/3 and S/5 anaesthesia monitors relates to normothermic patients aged approximately 35 years-old. However,

26Severinghaus worked on radar technology during World War II (Kofke 2003). 27The key factors are narcotics (see section on remifentanil in the appendix), age, temperature, pregnancy, and hair colour (Liem et al. 2004, showed that patients with red hair had a 19 % increased MAC requirement). CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

Table 9.1: MAC data based on age 1 year. The 95 % conﬁdence limits (CL) for ages 1 ≥ and 80 years are up to 1 % greater than at MAC40 (from Mapleson 1996). ∗ For the CO2 value see Eisele and Eger (1967).

Agent 1 year 40 years 80 years 95 % CL ( % MAC40) ± Halothane 0 95 0 75 0 58 6 Isoflurane 1·49 1·17 0·91 6 Enflurane 2·08 1·63 1·27 17 Sevoflurane 2·29 1·80 1·40 6 Desflurane 8·3 6·6 5·1 10 · · · Carbon dioxide∗ — 30 — — Xenon 92≈ 72 57 16 Nitrous oxide 133 104 81 8 since many of the thoracic patients are quite elderly it is more appropriate clinically to use an age-corrected MAC. A real-time software version which incorporates nitrous oxide is shown in Figure 9.5 (page 159). Print versions 28 in the form of graphs which allow for nitrous oxide use have been designed (Nickalls and Mapleson 2003), a separate chart being used for each volatile agent as shown in Figures 9.1–9.3. The use of nitrous oxide is accommodated in the charts by offsetting the right-hand N2O scales vertically by the amount given by MACage, volatile F E N0 2O × MACage, N2O · The print versions are available for download 29 and also in Allman and Wilson (2006). A nomogram by Lerou (2004) also gives age-corrected MAC.

Software The iso-MAC information is also available for some hand-held devices, for example, as the software MACpalm and ACTc. MACpalm: The MACpalm program is available from http://www.medicaldownload. com/medicalsoftware/macpalm.html. The installation is described in the MACpalm manual. ACTc: The Anesthesia Clinical Tutor and Calculator (ACTc) program is available from http://www.gasshead.com/. A manual is available at http://www.gasshead.com/ content/TutorACTc.pdf

28These allow anyone to conﬁdently use the common volatile agents with patients of any age without any guesswork or the need for superhuman memory. The motivation for developing a convenient graphic version arose from my wanting a paper-equivalent for use when working at another hospital, since I then had no access to my own real-time computer version based in the thoracic theatre at the City Hospital. 29http://www.nickalls.org/dick/xenon/rwdnXenon.html#workstation-mac CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

ISOFLURANE End-expired (%) in 67% 50% MAC N2O N2O 2 4 · 1 6 ...... 1 6 1 8 · ...... · · 2 2 •...... · ...... 1 4 1 6 1 4 .... •...... · · 2 0 ...... · · ...... •...... 1 2 1 4 xygen/air ...... · · o .. .. 1 8 ...... •...... 1 2 ...... 1 0 1 2 % . . . · ...... • ...... · · •...... · 1 6 ...... • ...... 1 0 100 · • ...... 0 8 1 0 ...... • ...... · · in ...... • ...... 1 4 · ...... • ...... 0 8 · ...... • ...... • .. 0 6 ...... • ...... · · (%) ...... 1 2 0 8 ...... • ...... · ...... 0 4 0 6 · • ...... • ...... · · 1 0 • ...... • ...... · • ...... • 0 2 0 4 0 6 ...... • ...... · · 0 8 · ...... • ...... End-tidal ...... • ...... 0 2 · ...... • ...... 0 ...... • ...... · 0 6 ...... • · c RWD Nickalls 2003 ...... 0

0 10 20 30 40 50 60 70 80 90 100 Age (years)

Figure 9.1: Age-related iso-MAC curves drawn using the data of Mapleson (1996), The dots on the iso-MAC curves are to help alignment. The left-hand ordinate scale indicates the end-expired isoflurane concentration when using an oxygen/air mixture. The two right-hand ordinate scales indicate the end-expired isoflurane concentration when using nitrous oxide 50 % and 67 % in oxygen. The vertical shifts for the nitrous oxide 50 % and 67 % scales are 0 56 and 0 75 respectively. · · For a given age and MAC the associated end-expired isoflurane concentration is read from the appropriate ordinate scale. For example, a MAC of 1 2 for a · 60-year old patient using isoflurane and nitrous oxide 67 % in oxygen requires an end-expired isoflurane concentration of approximately 0 5 %. · CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

SEVOFLURANE End-expired (%) in MAC 67% 50% 3 8 N O N O · 2 2 3 6 1 6 ...... 2 4 · · ...... · 2 6 3 4 • ...... 2 2 · · ...... · 2 4 3 2 ...... 1 4 ...... • ..... 2 0 · ...... · ...... 2 2 3 0 · ...... · xygen/air ...... • ...... 1 8 · o ...... · ...... 2 0 ...... · 2 8 ...... • ...... 1 6 · % ...... · 1 2 ...... 1 8 ...... · 2 6 · ...... • ...... 1 4 · • ...... · ...... 1 6 100 . ... • . · 2 4 ...... 1 2 ... • ...... · · ...... • ...... 1 4 in 1 0 ...... · 2 2 ...... • ...... 1 0 · ...... • ...... · · ...... • ...... · 1 2 2 0 ...... • ...... 0 8 · (%) ...... • ...... · ...... 1 0 ...... · 1 8 0 8 ...... • ...... 0 6 · ...... • ...... · · ...... 0 8 1 6 • ...... · ...... • ...... 0 4 • ...... · · ...... • • ...... · 0 6 1 4 ...... 0 6 ...... • ...... 0 2 · ...... · ...... • ...... 0 4 End-tidal · ...... · 1 2 ...... • ...... 0 · ...... • ...... · ...... 0 2 1 0 ...... • ...... • ...... · · ...... 0 0 8 c ...... · RWD Nickalls 2003 0 10 20 30 40 50 60 70 80 90 100 Age (years)

Figure 9.2: CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

DESFLURANE End-expired (%) in 67% 50% MAC 14 0 N2O N2O · 13 0 1 6 ...... 9 0 10 0 · ...... · · · •...... 12 0 ...... 8 0 9 0 . .... · ...... • ..... · · 1 4 ...... 7 0 8 0 11 0 · ...... xygen/air ...... • ...... · · o ...... · ...... • ..... 6 0 10 0 ...... 7 0 % ...... 1 2 ...... · ...... · · ...... • ..... · ...... • ...... 5 0 ...... 6 0 100 9 0 ...... • ...... · · · • ...... • ...... in ...... 1 0 ...... 4 0 5 0 8 0 ...... • ...... • ...... · ...... · · · ...... • ...... • ...... (%) ...... • ...... 3 0 4 0 7 0 ...... · ...... • ...... · · 0 8 ...... · ...... • ...... 2 0 ...... 3 0 6 0 • ...... • ...... · · · • ...... • ...... • ...... 1 0 2 0 5 0 0 6 ...... • ...... End-tidal ...... · ...... • ...... · · · ...... • ...... 0 1 0 4 0 ...... • ...... • · · ...... • ...... 3 0 c RWD Nickalls 2003 ...... 0 · 0 10 20 30 40 50 60 70 80 90 100 Age (years)

Figure 9.3: CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

Figure 9.4: An example of one of the new age and temperature-corrected MAC charts (see Section 9.4.3 for details). A Perl program prompts the user for agent name and patient age and then prints the chart out in the operating theatre. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

9.4.3 Temperature corrected MAC It is well established that MAC decreases as body temperature decreases. In fact even John Snow was aware of the influence of temperature, as the following extract shows.30 As the narcotism of frogs, by vapour too much diluted to affect animals of warm blood, depends merely on their temperature, it follows that by warming them, they ought to be put into the same condition, in this respect, as the higher classes of animals; and although I have not raised their temperature to the same degree, I have found that as it is increased, they cease to be affected by dilute vapour that would narcotise them at a lower temperature. Snow (1848a) However, it is less well known that (a) MAC decreases linearly with core temperature fall (approximately 2–5 % reduction in MAC per degree centigrade from 37 ◦C), and (b) the rate of MAC decrease with temperature fall is considerably more for vapours than for gases; for example the change in MAC / ◦C for halothane and cyclopropane in dogs is 5 3 % and 2 % respectively (Eger, Saidman, and Brandstater 1965b; Eger 1974). In humans the· linear rate of fall of MAC with temperature in the clinical range is approximately 5 % per degree centigrade for isoflurane, sevoflurane and desflurane, while that for nitrous oxide shows essentially no change (Eger 2001). These findings can be used to combine both age and temperature correction for MAC in a single chart—most easily done by creating a separate chart for each year of age—as shown in Figure 9.4. The additional functionality of such a chart is particularly useful, since the end-tidal agent requirement is most likely to be underestimated in young patients with a pyrexia. In practice, it is a simple matter to create and print this combined age and temperature-corrected iso-MAC chart for a specific patient on demand in the operating theatre.31 For example, suppose we wish to deliver 1 2 MAC to a 15 year-old patient with · a temperature of 39 ◦C. The Datex AS/3 and S/5 monitors show a value of 1 2 MAC for an end-tidal sevoflurane concentration (in air) of approximately 2 2 %, whereas· the age/temperature correction chart (see Figure 9.4) indicates that to achieve· the same MAC value in this patient (age 15 yrs; temp 39 ◦C) actually requires an end-tidal value of 2 8 % (i.e., a 27 % increase compared with the Datex displayed value). ·

9.4.4 Dosage and MAC correction Awareness The problem of awareness and the need for research in this area is often highlighted (Bergman et al. 2002, Guidry 2005, Leslie and Davidson 2010) and, as one might expect, data gathered by automatic anaesthesia management systems (AIMS) has been particularly

30This temperature work relates to chloroform—see his Experiment 16 (Snow 1848a). 31I have written a Perl program for this which is freely available. This program and separate charts for the ages 0–120 yrs are available on the thoracic CD-ROM in PDF format. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

useful in this regard. For example, using archived AIMS data, Driscoll et al. (2007) were not only able to establish volatile agent underdosing as the cause of awareness in three cases, but were also able to show that the clinicians’ manual component of the relevant parts of the anaesthesia records were unreliable and failed to reflect events accurately. More recently, the role of underdosing as a cause of awareness during anaesthesia has been highlighted in two large studies (Ghoneim et al. 2009, Xu et al. 2009), both of which found that awareness was associated with reduced drug dosage, being younger, and with non-volatile anaesthetic techniques. Similarly, Kent (2010) found that the two main causes of awareness in the Closed Claims database were light anaesthesia and anaesthetic delivery problems. Unfortunately EEG depth of consciousness monitoring techniques (e.g., BIS) are still problematic and unreliable (Mychaskiw et al. 2001, Rampersad and Mulroy 2005). Furthermore, in spite of several well publicised large neuromonitoring trials and surveys (Ekman et al. 2004, Myles et al. 2004; Sebel et al. 1997; Sebel et al. 2004; Avidan et al. 2008) there are still no data to suggest, in those cases where volatile agents are used, that neuromonitoring offers any advantage with regard to preventing awareness, over the rigorous implementation of ‘corrected’ MAC monitoring. Indeed, it is significant that the study of 20,000 patients by Sebel et al. (2004) actually showed that the BIS-monitored cohort had a higher incidence of awareness (0 18%) than the control cohort 32 (0 1%) (McCulloch 2005). In the BIS/MAC study by Avidan· et al. (2008) the authors concluded· that “...Our findings do not support routine BIS monitoring as part of standard practice.” Indeed, the associated editorial by Orser (2008) expressed concern regarding BIS-like devices, as follows.

. . . the delegation of critical elements of patient care to a “black box” approach, in which decisive factors are under proprietary control, must be avoided.”

Since the MAC paradime has been so successful (White, 2003), and because there are no known convincingly documented cases of awareness which are not associated with possible underdosing, it was recently suggested (Nickalls and Mahajan 2010)

. . . that the time has come to reformulate the concept and adopt a new and pragmatic working premis, namely, that all cases of awareness are due to underdosing unless there is convincing veriﬁable information to the contrary. . . . We . . . must confront the problem of underdosing by putting in place systems which we can have conﬁdence in to deliver an adequate dose, implementing the latest alarms (Umesh 2009), algorithms (Mashour, Esaki Vandervest et al. 2009), and corrections for age (Mapleson 1996, Nickalls and Mapleson 2003, Eger 2001), temperature (Eger 2001), and so forth as they come available.

In practice, however, there are studies showing a very low incidence of awareness even without using brain function monitoring (Pollard et al. 2007), and when volatile agents are used the end-tidal MAC approach is still the most reliable method for avoiding awareness,

32See letter by McCulloch (2005). CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

and is recommended by the Royal College of Anaesthetists (see RCOA 2006). Indeed, anaesthetists can easily be made even more aware of the current MAC status simply by using use a real-time colour-coded dial-display of corrected MAC (see Figure 9.5).

Figure 9.5: Left: Example of the real-time age-corrected MAC-widget displayed by the author’s open-source anaesthesia workstation software a interfaced to the Datex S/5 monitor. If the corrected MAC is too low (as shown in this case—total MAC 0 7) then, in addition to sounding an audible alarm, the dial of the ≈ · MAC-widget turns red. Right: Screenshot showing the MAC widget displaying a white dial (corrected MAC in the normal range). The MAC-widget software can easily be run on a laptop interfaced to an anaesthesia monitor.

What is the minimum MAC multiple which avoids awareness? 1 MAC has long been regarded as a signiﬁcant boundary since isoﬂurane at 1 MAC was shown to prevent implicit memory during surgery (Dwyer et al. 1992). More recently this problem was addressed by Hardman and Aitkenhead (2005), who stated that a stable end-tidal value greater than 1 MAC makes awareness extremely unlikely, as follows.

Risk of awareness correlates with depth of anaesthesia. . . . Fortunately, clinical investigations have shown a reasonably reliable association between recall and MAC; patients exhaling more than 0 8 MAC are unlikely to recall intraoperative events, and spontaneous recall is virtually· eliminated if > 1 MAC is exhaled, except after a sudden increase in inspired concentration. Hardman and Aitkenhead (2005)

That the end-tidal agent concentration should be maintained 1 MACage in order to reliably avoid awareness is consistent with a recent fMRI ﬁnding by≥ Kerssens et al. (2005), namely that while auditory activation in a group of 6 subjects (mean age 23 years) was detected CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

when breathing 1% end-tidal sevoflurane in oxygen/air (0 5 MACage), such activation was absent when breathing 2% end-tidal sevoflurane (i.e., when· breathing 1 MAC, since sevo MAC23 = 2%). It is significant, therefore, that in the BIS/MAC study by Avidan et al. (2008) the end-tidal agent concentration was less than 0 7 MAC in three of the four cases of definite awareness, and in seven of of the nine cases· of possible awareness. Thus the lower acceptable limit of 0 5 MAC suggested by Eger and Sonner (2005), Myles (2007) would seem to be far too low· to reliably prevent awareness. Consequently the values suggested by Hardman and Aitkenhead (2005)—see above—particularly when age and temperature corrected, would seem to be the best current advice. Note that the MAC value displayed by monitors having no age and temperature correction is most likely to underestimate the true MAC requirement in young patients with a high temperature (Section 9.4.3) and (possibly) with red hair (Liem et al. 2004). Indeed, it may be significant, therefore, that the two patients with documented awareness during BIS monitoring with sevoflurane reported by Ekman et al. (2004) were quite young (aged 16 and 22 years). Unfortunately the details of the aware patients who received volatile agents in the non-BIS group were not given.

Research In all work relating to depth of anaesthesia or awareness, it is essential to collect accurate real-time end-tidal anaesthetic gas (ETAG) concentrations and core temperatures using automated anaesthesia record keeping (AARK) equipment, drugs and doses used, as well as patient age, height, gender and hair-colour. The presented awareness-related data must be sufﬁcient to enable readers to calculate the corrected MAC for each patient; consequently the observed ETAG concentrations for each patient should always be presented. Where MAC corrections have been applied, the literature source of the corrections used must be indicated. Furthermore, mean age-corrected values need to be correctly determined; for example, the age correction for MAC is non-linear and hence the mean MAC value for a group must be derived from the corrected MAC of each individual subject/patient. In view of the importance of determining minimum MAC values for reliably preventing awareness, journal editors should ensure that awareness-related MAC data presented in journal articles are sufﬁcient to allow readers to determine the corrected MAC values for each patient (Nickalls and Mahajan 2010).

Data sharing Ideally all cases of inadvertent awareness should be documented, and archived, together with all the anaesthesia data associated with such cases (including all machine-automated end-tidal data) and placed in the public domain. Such a database could then form the basis of research, and may therefore, help “. . . recognise those few cases which may suggest either that the accepted dosage threshold should be raised or, perhaps, a signiﬁcant pharmacogenetic difference” (Nickalls and Mahajan 2010). CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

However, although original data documented in journals is still often difﬁcult to access from the authors or organisation (Wicherts et al. 2006, Anon 2006, Kaiser 2008), fortunately the climate of opinion is now strongly in favour of data-sharing, with funding organisations increasingly stipulating that authors place their data in open-access reposito- ries within a set period after publication in peer-reviewed journals (Short 2007, Wadman 2009). Nevertheless, we should continue to press for even more safeguards; for example, the adoption by anesthesia journals of an authorship policy specifying the preservation and sharing of original data (Anon 2009a). Authors and researchers need to embrace the new culture of ‘integrity, access and stewardship’ (Anon 2009b)—not only making the data available, but safe-guarding it as well.

9.4.5 References • Allman KG and Wilson IH (Eds.) (2006). Oxford Handbook of Anaesthesia. 2nd. ed., 1160–1162. • Anon [editorial] (2006). A fair share. Nature; 444, 653–654 (7th December). • Anon [editorial] (2009a). Authorship policies. Nature; 458, 1078 (30th April). • Anon [editorial] (2009b). Information overload. Nature; 460, 551 (30th July). • Avidan MS, Zhang L, Burnside BA et al. (2008). Anesthesia awareness and the bispectral index. New Engl. J. Med.; 358, 1097–1108. [see also the accompanying editorial by Orser (2008)] • Bergman IJ, Kluger MT and Short TG (2002). Awareness during general anaesthesia: a review of 81 cases from the Anaesthetic Incident Monitoring Study. Anaesthesia; 57, 549–556. • Borzova VV and Smith CE (2010). Monitoring and Prevention of Awareness in Trauma Anesthesia. The Internet Journal of Anesthesiology [ISSN: 1092-406X], 23, No 2. (http://www.ispub.com/) • Bowdle TA, Sebel PS, Ghoneim MM et al. (2005). How likely is awareness during anesthesia? Anesthesia and Analgesia; 100, 1545. [reply to letter by Eger EI and Sonner JM (2005)] • Driscoll WD, Columbia MA and Peterfreund RA (2007). Awareness during general anaesthesia: analysis of contributing causes aided by automatic data capture. Journal of Neurosurgical Anesthesiology; 19, 268–272. • Dwyer R, Bennett HL, Eger EI and Peterson N (1992). Isoﬂurane anesthesia prevents unconscious learning. Anesthesia and Analgesia; 75, 107–112. • Eger EI (1974). Anesthetic uptake and action. (Williams and Wilkins Company, Baltimore, USA), p. 12. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Eger EI (2001). Age, minimum alveolar anesthetic concentration, and minimum alveolar anesthetic concentration-awake. Anesthesia and Analgesia; 93, 947–953. [has an appendix on temperature correction] • Eger EI (2002). A brief history of the origin of Minimum Alveolar Concentration (MAC). Anesthesiology; 96, 238–239. • Eger EI II, Brandstater B, Saidman IJ, Regan M, Severinghaus J and Munson E (1965). Equipotent alveolar concentrations of methoxyﬂurane, halothane, diethyl ether, ﬂuroxene, cyclopropane, xenon and nitrous oxide in the dog. Anesthesiology; 26, 771–777. • Eger EI, Eisenkraft JB and Weiskopf RB (2003). The pharmacology of inhaled anesthetics. 327 pp. (Sponsored by the Dannemiller Memorial Education Foundation, and also Baxter Healthcare Corporation) [Library of Congress no. TXV1-035635] • Eger EI II, Saidman IJ and Brandstater B (1965a). Minimum alveolar anesthetic concentration: A standard of anesthetic potency. Anesthesiology; 26, 756–763. • Eger EI II, Saidman IJ and Brandstater B (1965b). Temperature dependence of halothane and cyclopropane anesthesia in dogs: Correlation with some theories of anesthetic action. Anesthesiology; 26, 764–770. [from Eger 1974] • Eger EI and Sonner JM (2005). How likely is awareness during anesthesia? Anes- thesia and Analgesia; 100, 1544. [see reply by Bowdle et al. (2005)] • Eisele JH and Eger EI (1967). Narcotic properties of carbon dioxide in the dog. Anesthesiology; 28, 856–865. [cited from Anaesthesia and Analgesia (2001); 93, 398] • Ekman A, Lindholm M-L, Lennmarken C and Sandin R (2004). Reduction in the incidence of awareness using BIS monitoring. Acta Anaesthesiol. Scand.; 48, 20–26. • Ghoneim MM, Block RI (1997) Learning and memory during general anesthesia. An update. Anesthesiology; 87, 387–410 • Ghoneim MM, Block RI, Haffarnan M and Mathews M (2009). Awareness during anesthesia: risk factors, causes and sequelae: a review of reported cases in the literature. Anesthesia and Analgesia; 108, 527–535. • Gregory GA, Eger EI and Munson ES (1969). The relationship between age and halothane requirement in man. Anesthesiology; 30, 488–491. [from Eger 1974] • Guidry OF (2005). Awareness monitoring: some personal opinions. ASA Newslet- ter; 69 (January). http://www.asahq.org/ • Hardman JG and Aitkenhead AR (2005). Awareness during anaesthesia. Continuing Education in Anaesthesia, Critical Care & Pain; 5, 183–186. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Kaiser J (2008). Making clinical data widely available. Science; 322, 217–218 (October 10). • Katoh T, Bito H and Sato S (2000). Influence of age on hypnotic requirement, Bispectral Index, and 95 % spectral edge frequency associated with sedation induced by sevoflurane. Anesthesiology; 92, 55–61. • Kent CD (2010). Awareness during general anesthesia: ASA Closed Claims Database and Anesthesia Awareness Registry. ASA Newsletter; 74 (February), 14–16. http://www.asahq.org/ • Kerssens C, Hamann S, Peltier S, Hu XP, Byas-Smith MG and Sebel PS (2005). At- tenuated brain response to auditory word stimulation with sevoflurane. A functional magnetic imaging study in humans. Anesthesiology; 103, 11–19. • Kofke WA (2003). An interview with John W. Severinghaus. Association of University Anesthesiologists (AUA) Update; Fall 2003 issue. http://www.auahq. org/fall03aua.pdf • Lerou JGC (2004). Nomogram to estimate age-related MAC. Br. J. Anaesth.; 93, 288–291. • Leslie K and Davidson (2010). Awareness during anesthesia: a problem without solutions? Minerva Anestesiologica; 76, 624–628.

• Liem EB, Lin C-M, Suleman M, Doufas AG, Gregg RG, Veauthier JM, Loyd G and Sessler DI (2004). Anesthetic requirement is increased in redheads. Anesthesiology, 101, 279–83. [MAC requirement is increased by 19 %] • MacQuitty B (1969). The battle for oblivion. (GG Harrap & Co Ltd., London.)

• Maltby RJ (Ed.) (2002). Notable names in anaesthesia. (Royal Society of Medicine Press, London). [ISBN 1853-155-128] [includes EI Eger, WW Mapleson, J Sever- inghaus, J Snow] • Mapleson WW (1979). From Clover to computer: towards programmed anaesthesia? Anaesthesia; 34: 163–172. [an edited version of the 19th Joseph Clover Lecture]

• Mapleson WW (1996). Effect of age on MAC in humans: a meta-analysis Br. J. Anaesth.; 76: 179–185. http://bja.oxfordjournals.org/content/76/2/ 179.full.pdf • Mashour GA, Esaki RK, Vandervest JC, Shanks A and Kheterpal S (2009). A novel electronic algorithm for detecting potentially insufﬁcient anesthesia: implications for the prevention of intraoperative awareness. J. Clin. Monit. Comput.; 23, 273–277. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• McCulloch TJ (2005). Use of BIS monitoring was not associated with a reduced incidence of awareness. Anesthesia and Analgesia; 100, 1221–1222. [comments on the Sebel et al. 2004 paper] • Merkel G and Eger EI (1963). A comparative study of halothane and halopropane anesthesia: Including a method for determining equipotency. Anesthesiology; 24, 346–57. • Mychaskiw G, Horowitz M, Sachdev V and Heath BJ (2001). Explicit intraoperative recall at bispectral index of 47. Anesth. Analg.; 92, 808–809. [28 yr male with awareness during the sternal split for a CABG. Values at this stage were FIO 0 26, FIN O 0 67, inspired sevoflurane 2%] 2 · 2 · • Myles PS (2007). Prevention of awareness during anaesthesia. Best Practice and Research in Clinical Anaesthesiology; 21, 345–355. • Myles PS, Leslie K, McNeil J, Forbes A and Chan MT (2004). Bispectral index monitoring to prevent awareness during anaesthesia: the B-Aware randomised controlled trial. Lancet; 363, 1757–1763. • Nickalls RWD and Mapleson WW (2003). Age-related iso-MAC charts for isoflurane, sevoflurane and desflurane in man. Br. J. Anaesth.; 91, 170–174. http://dx.doi.org/10.1093/bja/aeg132 • Nickalls RWD and Mahajan RP (2010). Awareness and anaesthesia: think dose, think data. Br. J. Anaesth.; 104, 1–2. [Editorial] http://dx.doi.org/10.1093/bja/aep360 • Orser BA (2008). Depth-of-anesthesia monitor and the frequency of intraoperative awareness. New Engl. J. Med.; 358, 1189–1191. [editorial to the Avidan et al. 2008 study] • Peyton PJ, Chong M, Stuart-Andrews C, Robinson GJB, Pierce R and Thompson BR (2007). Measurement of anaesthetics in blood using a conventional infrared clinical gas analyzer. Anesthesia and Analgesia; 105, 680–687. [accuracy and precision of the Datex Capnomac compares well with gas chromatography methods]

• Pollard RJ, Coyle JP, Gilbert RL and Beck JE (2007). Intraoperative awareness in a regional medical system. Anesthesiology, 106, 269–274. • Rampersad SE and Mulroy MF (2005). A case of awareness despite an ‘adequate depth of anesthesia’ as indicated by a bispectral index monitor. Anesth. Analg.; 100, 1363–1364.

• RCOA (2006). Loss of consciousness monitoring. A statement by the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Sandin RH, Enlund G, Samuelsson P and Lenmarken C (2000). Awareness during anaesthesia: a prospective case study. Lancet; 355, 707–711. • Sebel PS, Lang E, Rampi IL et al. (1997). A multicenter study of bispectral electroen- cephalogram analysis for monitoring anaesthetic effect. Anaesthesia and Analgesia; 84, 891–899. • Sebel PS, Bowdle TA, Ghoneim MM et al. (2004). The incidence of awareness during anesthesia: a multicenter United States study. Anesthesia and Analgesia; 99, 833–839.

• Severinghaus JW (2009). Gadgeteering for health care: [The JW Severinghaus lecture on translational science] Anesthesiology; 110, 721–728. • Short R (2007). Open access will mean peer review becomes “the job of the many, not the select few”. British Medical Journal; 334 (17 February), 330. • Snow J (1847). On the inhalation of the vapour of ether in surgical operations. Reprinted in Br. J. Anaesth. (1953); 25, pp. 53–67 (part 1), 162–169 (part 2), 253–262 (part 3), 349–382 (part 4). Also available from UCLA Department of Epidemiology website: http://www.ph.ucla.edu/epi/snow.html • Snow J (1848a). On narcotism by the inhalation of vapours (Part I). London Medical Gazette; 6NS 33, 850–854 [included in Snow 1848b]

• Snow J (1848b). On narcotism by the inhalation of vapours (parts I–VII). (Wilson and Ogilvy, London). A facsimile edition with an introductory essay by RH Ellis (Royal Society of Medicine Services Ltd., London, 1991) ISBN 1-85315-158-0 • Soto R, Nguyen TC and Smith RA (2005). A comparison of Bispectral Index and Entropy, or how to misinterpret both. Anesthesia and Analgesia; 100, 1059–1061.

• Stone ME, Meyer MR and Alston TA (2010). Elton Romeo Smilie, the not-quite discoverer of ether anesthesia. Anesthesia & Analgesia; 110, 195–197. • Umesh G, Jasvinder K and Shetty N (2009). Low minimum alveolar concentration alarms: a standard for preventing awareness during general anaesthesia. J. Clin. Monit. Comput.; 23, 185–186. • Vinten-Johansen P, Brody H, Paneth N, Rachman S and Rip M (2003). Cholera, chloroform and the science of medicine: a life of John Snow. (Oxford University Press, UK) • Wadman M (2009). Open-access policy ﬂourishes at NIH. Nature; 458, 690–691 (9th April).

336NS indicates New Series No 6. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• White D (2003). Uses of MAC. Br. J. Anaesth.; 91, 167–169. [editorial] • Wicherts JM, Borsboom D, Kats J and Molenaar D (2006). The poor availability of psychological research data for reanalysis. American Psychologist; 61, 726–728. [cited in Anon 2006] • Xu L, Wu AS, Yue Y (2009). The incidence of intra-operative awareness during general anesthesia in China: a multicenter observational study. Acta Anaesthesiologica Scandinavica; 53, 873–882.

9.5 Arterial line

9.5.1 History The first direct measurement of arterial blood pressure is generally said to have been in 1733 by Stephen Hales (1677–1761) using a glass tube 9 feet long connected flexibly (using the trachea of a goose) to the femoral and carotid arteries of horses (Comroe 1977, pp. 15–17). Some eight years earlier the physician and mathematician Daniel Bernoulli (1700–1782) was measuring fluid pressure in pipes using a narrow tube (Quinney 1997). In 1828 Jean-Louis Poiseuille (1799–1869) developed this technique further (see also: Zuck 1997) using a U-tube filled with mercury to determine the pressure at various points along the aorta (his later researches into flow in small tubes led to his famous Poiseuille’s Law). The first clinically useful placement of an arterial catheter for this purpose was developed by Peterson et al. (1949). They described their method as follows.

A small plastic catheter, inserted into an artery through a needle, is left in the artery when the needle is withdrawn. Attached to a capacitance manometer, this technique permits recording for long periods of time without discomfort and allows relatively free mobility of the subject. Comroe (1977), p. 36

Use of the strain-gauge (Tomlinson, 1876) for transducing arterial pressure was ﬁrst described a few years earlier by Lambert and Wood (1947). See letter by Kannan (2005) for recent use of ultrasound to facilitate arterial line placement.

• Barr PO (1961). Percutaneous puncture of the radial artery with a multipurpose Teﬂon cannula for indwelling use. Acta Physiol. Scand; 51, 643. • Comroe JH (1977). Retrospectroscope: insights into medical discovery. (Von Gehr Press, Menlo Park, California, USA). • El-Hamamsy I, Duurrleman¨ N, Stevens L-M, Leung TK, Theoret S, Carrier M and Perrault LP (2003). Incidence and outcome of radial artery infections following cardiac surgery. Annals of Thoracic Surgery; 76, 801–804. [strict systematic changing of arterial lines on a timely basis is unwarranted] CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Hales S (1733). Statical essays: Containing haemastatics. vol 2. (Innys and Manby, London). 361 pp. • Kannan S (2005). Another use for ultrasound in the ICU. Anaesthesia; 60, 944. [used a 7 MHz ultrasound probe; useful in oedematous patients; 7 refs]

• Peterson LH, Dripps RD and Risman G (1949). A method for recording the arterial pressure pulse and blood pressure in man. Am. Heart J.; 37, 771–782. • Poiseuille JLM (1828). Recherches sur la Force du Coeur Aortique; These` No. 166 (Didot, Paris).

• Quinney DA (1997). Daniel Bernoulli and the making of the ﬂuid equation. http://plus.maths.org.uk/issue1/bern/ • Tomlinson H (1876). On the increase in resistance to the passage of an electric current produced on wires by stretching. Proc. Soc. Exp. Biol. Med.; 64, 186–190.

• Wong AYC and O’Regan AM (2003). Gangrene of digits associated with radial artery cannulation. Anaesthesia; 58, 1034–1035. [overview of rare complications, and discusses use of the ‘modiﬁed’ Allen test] • Zuck D (1997). Anaesthesia and physiology: the ﬁrst twenty years. The History of Anaesthesia Society Proceedings; 20, 75–90.

9.5.2 Anatomy An extensive collateral network of superficial and deep palmar arches normally connects the radial and ulna arteries in the hand. However, in 58 % of patients the palmar arches are incomplete, and of these ‘incomplete’ cases approximately 4 % will suffer significant vascular insufficiency if the radial artery is removed or occluded (Cable, Mullany & Schaff 1999; Lippert H and Pabst R 1985) — see Allen test below.

• Brzezinski M, Luisetti T and London MJ (2009). Radial Artery Cannulation: A Com- prehensive Review of Recent Anatomic and Physiologic Investigations. Anesthesia and Analgesia, 109, 1763–1781. • Coleman SS and Anson BJ (1961). Arterial patterns in the hand based upon a study of 650 specimens. Surg. Gynecol. Obstet.; 113, 409.

• Husum B and Palm T (1978). Arterial dominance in the hand. Br. J. Anaesth.; 50, 913. • Lippert H and Pabst R (1985). Arterial variations in man: classiﬁcation and frequency. (JF Bergmann Verlag, Munich, Germany). [cited by Cable, Mullany & Schaff 1999] CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Riekkinen HV, Karkola KO and Kankainen A (2003). The radial artery is larger than the ulna. Annals of Thoracic Surgery, 75, 882–884. [mean internal diameter is 3 1 mm (range: 2–4 mm)] · 9.5.3 Allen test Edgar V Allen (1900–1961) was a physician at the Mayo Clinic, and co-author of a textbook on vascular medicine (Allen, Barker and Hines 1946). He described a simple test (the so-called Allen test) to reveal ulnar or radial artery occlusion at the wrist (Allen 1929). His description with respect to the ulnar artery is as follows.

If obstruction of the ulnar artery is suspected, the radial arteries are located by their pulsations; the examiner places one thumb lightly over each radial, with the four fingers of each hand behind the patient’s wrist, thus holding the wrist lightly between the thumb and fingers. The patient closes his hands as tightly as possible for a period of 1 minute in order to squeeze the blood out of the hand; the examiner compresses each wrist between the thumb and fingers, thus occluding the radial arteries; the patient quickly extends his fingers partially while compression of the radial arteries is maintained by the examiner. The return of color to the hand and fingers is noted. In individuals with an intact arterial tree the pallor is quickly replaced by rubor of a degree higher than normal. Cable, Mullany & Schaff (1999)

Before ‘harvesting’34 or even cannulating the radial or ulnar artery, the adequacy of collateral vessels should be assessed by an Allen test (after EV Allen 1929), to determine if they alone can adequately supply the hand. If a vessel fails the Allen test, then the other vessel certainly should not be harvested, and probably ought not to be cannulated either.

Modiﬁed Allen test Erroneous results can arise if the test is not performed correctly (Greenhow 1972). Note that the wrist must not be hyperextended as this can cause vessel occlusion and invalidate the test (Fuhrman et al. 1992). The slightly more controlled so-called ‘modiﬁed’ Allen test (Vaghadia et al. 1988) is now generally used (compressing both arteries simultaneously), in conjunction with the following ‘pass’ or ‘fail’ times.

[both] the ulnar and radial arteries are compressed at the wrist for 30 secs to induce hand ischaemia, while the hand is drained of blood by tight clenching.≥ The test vessel is then released and the time to adequate perfusion of the tips of the ﬁngers and thumb noted. The vessel is said to pass or fail the test as follows: pass (< 5 secs); equivocal (6–10 secs); fail (> 10 secs) Royse et al. (1999)

34The radial artery is sometimes removed (known as ‘harvesting’) for use in coronary-artery or temporal-artery bypass procedures—see Royse et al. (1999). CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

Note that the vessels should actually be compressed just proximal to the point where the tip of the cannula is expected to lie, in order to detect essential collateral branches distal to the likely cannula tip position (Gandhi and Reynolds 1983). Plethysmography is more sensitive than either the Allen test or pulse-oximetry (Fuhrman et al. 1992).

• Allen, EV (1929). Thrombo-angiitis obliterans:35 methods of diagnosis of chronic occlusive arterial lesions distal to the wrist, with illustrative cases. American Journal of Medical Sciences; 178 (August), 237–244. • Allen, EV, Barker NW and Hines EA (1946). Peripheral vascular diseases. (WB Saunders Company, Philadelphia, USA). [from Wright 1952] • Cable DG, Mullany CJ and Schaff HV (1999). The Allen test. Annals of Thoracic Surgery; 67, 876–877. [excellent – includes a photograph of Allen]

• Fuhrman TM, Pippin WD, Talmage LA and Reilley TE (1992). Evaluation of collateral circulation of the hand. J. Clinical Monitoring and Computing; 8, 28–32. • Gandhi SK and Reynolds AC (1983). A modiﬁcation of Allen’s test to detect aberrant ulna collateral circulation. Anesthesiology; 59, 147–148.

• Glavin RJ and Jones HM (1989). Assessing collateral circulation in the hand — four methods compared. Anaesthesia; 44, 594–595. • Greenhow DE (1972). Incorrect performance of Allen’s test—ulnar-artery flow erroneously presumed inadequate. Anesthesiology; 37, 356–357. • Paul BZS and Feeney CM (2003). Combining the modified Allen’s test and pulse oximetry for evaluating ulna collateral circulation to the hand for radial artery catheterization of the ED 36 patient. The California Journal of Emergency Medicine; 4, 89–91. • Royse et al. (1999). Radial artery harvest technique, use and functional outcome. European J. of Cardio-thoracic Surgery; 15, 186–193. [available for download at: http://www.heartweb.com.au/] • Sinton I (2003). Digital ischaemia after ulnar artery cannulation. Br. J. Anaesth.; 91, 302–303. [letter] • Vaghadia H, Schechter MT, Sheps SB and Jenkins LC (1988). Evaluation of a postocclusive reactive circulatory hyperaemia (PORCH) test for the assessment of ulna collateral circulation. Can. J. Anaesth.; 35, 591–8. [a ‘modified’ Allen test]

35Buerger’s disease. 36Emergency Department CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

9.5.4 Systolic pressure variation Real-time measurement of systolic-diastolic pressure variation with respect to spontaneous ventilation or with IPPV may be useful as an index of hypovolaemia, either via pulse oximetry waveform variation or via direct arterial measurement. • Fujita Y and Sari A (2003). On-line monitoring of systolic pressure variation. Anesthesia and Analgesia; 96, 1529–1530. • Reuter DA, Felbinger TW, Kilger E et al. (2002). Optimizing ﬂuid therapy in mechanically ventilated patients after cardiac surgery by an on-line monitoring of left ventricular stroke volume variations: comparison with aortic systolic pressure variations. Br. J. Anaesth.; 88, 124–126.

9.5.5 Complications Complications from arterial cannulation are rare, but therapeutic vasodilation in the form of stellate ganglion block (Gyanendra et al. 1998), or use of intra-arterial phentolamine (Burrell 1977) or papaverine is sometimes required. • Burrell AR (1977). Treatment of ischaemia following radial artery cannulation. Anaesthesia and Intensive Care; 5, 388. [used intra-arterial phentolamine (diluted to 0 5 mg/ml) and gave a 3 ml bolus, followed a while later by a 5 ml bolus.]. · • Gyanendra U and Kashyap L (1998). Accidental single brachial artery puncture leading to reversible ischaemia of the upper limb. Intensive Care Medicine; 24, 197. [severe spasm following 16-G needle puncture treated using repeated stellate ganglion block] • Leroy O, Billiau V, Beuscart C, Santre C, Chidiac C, Ramage C and Mouton Y (1989). Nosocomial infections associated with long-term radial artery cannulation. Intensive Care Med.; 15, 241–246. • Lindsay SL, Kerridge R and Collett BJ (1987). Abscess following cannulation of the radial artery. Anaesthesia; 42, 654–657. • Mastan M and Van Oldenbeek C (2003). Digital ischaemia after ulnar artery cannulation. Br. J. Anaesth.; 90, 111. [letter]. [see reply: Sinton I (2003); 91, 302–303; uses a modiﬁed Allen test] • Ryan DW (1989). Limitations of invasive intravascular monitoring. Intensive Therapy and Clinical Monitoring; 10, 216–220. • Slogoff S, Keats AS and Arlund C (1983). On the safety of radial artery cannulation. Anesthesiology; 59, 42–47. • Wilkins RG (1985). Radial artery cannulation and ischaemic damage—a review. Anaesthesia; 40, 896–899. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

9.6 Central venous catheter

9.6.1 History The development of intravascular catheters and the techniques for inserting them has resulted in important advances both diagnostically (angiography) and therapeutically (CVP & Hickman lines; angioplasty).

Werner Forssmann In the 1920s Werner Forssmann (1904–1979), then a surgical resident, was looking for safer ways of delivering cardio-active drugs to the heart (i.e., other than via direct needle injection), and eventually he hit upon the idea of using a long IV catheter. In 1929, when he was only 26, Forssmann tested this idea in a Berlin hospital, by inserting a long urinary catheter via the antecubital fossa into his own right atrium and confirmed its intra-cardiac position radiologically. He went on to use this method for injecting intra-cardiac contrast in animals, paving the way for diagnostic cardiac angiography, for which he was awarded the Nobel Prize in 1956, together with Cournand (1895–1988) & Richards (1895–1973). The following translation of part of Fossmann’s original article (Forssmann, 1929) is by Luft (1994). In cases of shock, such as those engendered by sudden cardiac standstill, or during anesthetic emergencies and poisonings, it may be desirable to deliver medications directly to the heart itself. . . . Nevertheless intracardiac puncture is a dangerous procedure for several reasons, including injury to the coronary arteries and its branches, pericardial tamponade, injury to the diaphragm, and pneumothorax. . . . For these reasons I considered a new method to approach the heart in a less dangerous fashion, namely the catheterisation of the right heart from the venous system. Experiments on a cadaver were productive. I was able to catheterize any vein in the antecubital fossa and was able to regularly reach the right ventricle. . . . I next undertook experiments on a living subject, namely on myself. I first convinced a colleague to puncture a vein in my right antecubital fossa with a large needle. I next advanced a well-oiled ureteral catheter size 4 Charriere in diameter through the needle into the vein. The catheter allowed itself to be advanced with trivial ease to 35 cm. Because my friend objected to our proceeding with these experiments further, we broke them off even though I felt perfectly well. One week later I tried again alone. I anesthetized my own left antecubital fossa and because I was not able to manipulate the needle by myself I constructed a “cut-down” and advanced the catheter along its full 65 cm length. From surface estimates, I reasoned that the catheter tip would be at the level of the heart. I documented the position of the catheter with roentgenograms that I obtained by standing in front of the fluoroscope while observing the catheter in a mirror held by a nurse. In conclusion, I would like to point out the utility of this technique in providing new opportunities to research the metabolic activities and actions of the heart. Forssemann (1929) [From: Luft (1994)] CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

Andre´ Cournand and Dickinson Richards Cournand and Richards extended Forssmann’s intravascular catheter concept and developed long single and double-lumen catheters which allowed them to sample blood and pressures from the right heart and pulmonary artery (c. 1940s). They also determined approximate left atrial pressures by wedging the catheters by pushing them as far as they would go (i.e., not balloon-occlusion wedge pressures as determined by Swan and Ganz in 1967). They studied cardio-pulmonary physiology and patho-physiology, and showed that hypoxia, sufﬁcient to make the arterial oxygen saturation less than 80 %, resulted in signiﬁcant pulmonary vasoconstriction and a rise in pulmonary artery pressure (Cournand 1956; Richards 1956). Interestingly, they also showed that an infusion of acetylcholine (0 5 mg/min) into the pulmonary artery reversed the pulmonary vasoconstriction while not affecting· the systemic blood pressure (Harris et al. 1956; Cournand 1956).

Sven-Ivar Seldinger Radiologists often need to insert long large-diameter catheters into arteries in order to inject contrast into distant vessels. In the early 1950s, however, the two existing techniques had significant shortcomings. For example, the catheter-through-needle technique was associated with a significant leak at the vessel entry point (catheter smaller than needle), and the long narrow catheters made it difficult to inject contrast fast enough to be effective. The catheter-over-needle technique was only feasible with quite short catheters (since the needle did not bend, and long needles were difficult to manipulate safely). In 1952 Sven-Ivar Seldinger (1921–1998) a Swedish radiologist at the Karolinska Hospital, Stockholm overcame these difficulties by developing his catheter-over-guidewire technique (Seldinger 1953; Seldinger 1987; Higgs et al. 2005; Greitz 1999). He actually used a guidewire with a straight flexible tip. Seldinger described the process of development as follows.

However, rightly or not, some people considered the procedure [translumbar aortography] hazardous and searched for a technique where a catheter could be inserted via a peripheral artery. Surgical cut down methods had been reported . . . and Bierman et al. (1951) . . . suggested a percutaneous technique in which a catheter was inserted through a puncture instrument into the femoral artery and advanced to the aorta. The catheter had to be wide enough to permit a very rapid injection. If not, the contrast medium would be so diluted by the voluminous aortic bloodﬂow that diagnostic angiographs would not be obtained. In turn a very wide-bore puncture instrument, with consequent risk of trauma, was required. Thus there was obviously a need for an improved percutaneous method for aortography, and one of the requirements to the solution was an increased bore of the catheter. . . . There existed a “puncture equipment” named after Cournand, consisting of an inner sharp needle in an outer blunt cannula, the edge exceeding the cannula by one or two mm. One alternative was to use a ﬂexible catheter instead of the cannula, but it would certainly be tricky to handle an inner needle, half a meter or more long. I avoided this CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

trouble by cutting a side hole on a polythene catheter at such a level that a cutting needle of convenient length, when inserted through it, exceeded the tip of the catheter by one or two mm. After some moulding of the catheter and a minute incision in the skin, this instrument could be inserted into the artery by percutaneous puncture. Some obvious disadvantages were inherent in this technique. For instance, the thin- walled catheters were so flexible that, sometimes it was impossible to advance them further into the vessel. This difficulty could often be overcome. When intravascular position was obtained, the needle could be withdrawn from the side hole and replaced by a semi-flexible metal wire which was introduced through the entire length of the catheter to support it. Now! After an unsuccessful attempt to use this technique I found myself, disappointed and sad, with three objects in my hand—a needle, a wire and a catheter—and, in a split second, I realised in what sequence I should use them: needle in—wire in—needle off—catheter on wire—catheter in—catheter advance—wire off. I have been asked how this idea turned up and I can quote Phokion,37 the Greek: “I had a severe attack of common sense.” The tools could not be less complicated; they could be found among the instruments of any hospital and, if necessary, could be completed at the nearest ironmonger’s. Any handy person could use them. With the ‘beginner’s luck’ the first angiography performed with this technique was a success: a subclavian arteriography, with one single exposure, the catheter introduced through the brachial artery after puncture at the cubital level, which revealed a parathyroid adenoma, unsuccessfully searched for by the surgeon in the mediastinum, With my permission, the Head of the Department, Knut Lindblom, reported on the technique at the Radiological Congress of Northern Europe which took place in Helsinki one week later, in June 1952. Seldinger (1987)

The January 1984 issue of the American Journal of Roentgenology 38 (volume 142) celebrated the 30th anniversary of the Seldinger Technique with a series of articles on Seldinger 39. The article by Doby (1984) gives an excellent historical overview, and includes some detailed sketches by Seldinger himself relating to his development of the technique.

Stanley Baum and Herbert Abrams A not uncommon problem associated with the straight guidewire, particularly when cannulating the femoral artery, was failure to advance easily. This problem was largely overcome in 1964 by Baum and Abrams’ development of the J-tipped catheter which is threaded over the guidewire (Baum and Abrams 1964). Once the catheter has been

37Phocion (402–317 B.C.): Athenian statesman, general, and pupil of Plato. 38See their web site at http://www.ajronline.org/ 39The main articles are listed in the references. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

positioned above the obstruction then the catheter is changed (by reinserting the guidewire) for a special angiography catheter.

Charles Dotter At approximately the same time the American radiologist Charles Dotter (1920–1985), widely regarded as the father of interventional radiology, was beginning to lay the foundations of this new speciality at the Oregon Health State University,40 in conjunction with his student Melvin Judkins. In 1963 Dotter inadvertently unblocked an occluded right iliac artery while passing a catheter through it in order to reach the aorta for an abdominal aortogram, and realised that intravascular catheterisation can be used therapeutically as well as diagnostically. On 16 January 1964, Dotter, together with Judkins, performed the first deliberate dilation of an arterial obstruction, and thereafter developed the tools and techniques for what is now known as transluminal angioplasty (Payne 2001). Dotter also developed the first safety J-tipped guidewire (Judkins et al. 1967), flow-guided catheter, an intravascular biopsy catheter, and intravascular coils which were the forerunner of expandable stents (http://www.ohsu.edu/dotter/ctdotter.htm).

PICC catheters—Broviac JW and Hickman With the advent of intensive care, intravenous nutrition and chemotherapy central catheters were increasingly used for long periods of time, leading to signiﬁcant catheter-related infections. This prompted engineers to address design and materials issues, leading to new long-term so-called PICC catheters,41 ﬁrst by Broviac et al. (1973) and later by Hickman et al. (1979). Special valved catheters (Croshong catheter) were developed by Bard Access Systems.

9.6.2 References • Baum S and Abrams HL (1964). A J-shaped catheter for retrograde catheterization of tortuous vessels. Radiology; 83, 436–437. [ﬁrst description/use of the J-catheter]

• Broviac JW, Cole JJ and Scribner BH (1973). A silicone rubber atrial catheter for prolonged parenteral alimentation. Surg. Gynaecol. Obstet.; 136, 602–606. • Cournand AF (1956). Control of the pulmonary circulation in man with some remarks on methodology. (Nobel Lecture)

• Doby T (1984). A tribute to Sven-Ivar Seldinger. American Journal of Roentgenol- ogy; 142 (Jan), 1–3. [http://www.ajronline.org/cgi/reprint/142/1/1. pdf]

40see http://www.ptca.org/nv/history.html, and also http://www.ohsu.edu/dotter/ 41PICC — Peripherally Inserted Central Catheter. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Forssmann W (1929). Catheterization of the right heart. Klinische Wochenschrift; 8 (No. 45), 2085–2087. [from Luft 1994] • Greitz T (1999). Sven-Ivar Seldinger. Am. J. Neuroradiol.; 20 (June/July), 1180– 1181. [http://www.ajnr.org/cgi/reprint/20/6/1180] • Harris P, Fritts HW, Clauss RH, Odell JE and Cournand A (1956). Inﬂuence of acetylcholine on human pulmonary circulation under normal and hypoxic conditions. Proc. Soc. Exptl. Biol. Med.; 93, 77. • Higgs ZCJ, Macafee DAL, Braithwaite BD and Maxwell-Armstrong CA (2005). The Seldinger technique: 50 years on. Lancet, 366, 1407–1409. • Judkins M, Kidd HJ et al. (1967). Lumen-following J-guide for catheterization of tortuous vessels. Radiology; 88, 1127. • Luft FC (1994). The birth of a common procedure. Annals of Internal Medicine; 120, 974. • Payne MM (2001). Charles Theodore Dotter, the father of intervention. Texas Heart Institute Journal; 28, 28–38. http://www.ncbi.nlm.nih.gov/pmc/journals/ 92/. • Richards DW (1956). The contribution of right heart catheterization to physiology and medicine, with some observations on the pathophysiology of pulmonary heart disease. (Nobel Lecture) • Seldinger SI (1953). Catheter replacement of the needle in percutaneous arteriography: a new technique. Acta Radiologica Scandinavica; 39, 368–376. • Seldinger SI (1987). A leaf out of the history of angiography. In: Silvestre ME, Abecasis F and Veiga-Pires JA (1987); Radiology: Faculty Pro- ceedings of the 6th European Congress of Radiology, Lisbon, Portugal, 31 May–6 June 1987. (Excerpta Medica, International Congress Series No. 749; Elsevier Sci- ence Publishers BV [Biomedical Division], Amsterdam, The Netherlands.) ISBN: 0-444-80947-3. p. 3–6. [from Greitz (1999)] • (1984) — special ‘Seldinger’ issue of the American Journal of Roentgenology; 142 (Jan): – Sven-Ivar Seldinger: a biography and bibliography. American Journal of Roentgenology; 142 (Jan), 4. – The Seldinger technique. American Journal of Roentgenology; 142 (Jan), 5–7. [a reproduction of Seldinger’s original article] – Testimonials to Seldinger. American Journal of Roentgenology; 142 (Jan), 8–11. [reﬂections by Dotter CT, Grainger RG, Nordenstrom¨ B, Abrams HL, and Athanasoulis CA] CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

9.6.3 Optimum position The current view regarding the optimum location of the tip of a CVP-catheter is driven by the need to avoid the possibility of the catheter migrating into the pericardium. Conse- quently the tip should be above the pericardial reflection on to the SVC (Chalkiadis and Goucke 1998), which is generally held to be at the level of the carina (T4–T5; sternal angle)—i.e., above the left and right atria. Ryu et al. (2007) give a simple landmark-based method for safely positioning the tip of the CVP line in relation to the carina. Several articles have appeared recently describing the use of ultrasound to facilitate CVP-line placement, including a good editorial by Scott (2004). Techniques for correcting/relocating subclavian and internal-jugular catheters which have taken an aberrant course are addressed by Pattnaik and Bodra (1999); they highlight an article by Kayal et al. (1989) who used ultrasound while flushing with saline to detect when the tip of the catheter is in the correct vessel. Pattnaik and Bodra (1999) suggest listening with a stethoscope is useful. An alternative approach to the ‘aberrant catheter’ problem, might be to consider placing a new J-wire into the same vein via the proximal lumen 42 (hopefully in the internal jugular vein), removing the misplaced CVP line and then railroading a new one—with luck the new wire will be in a better location (one could check the new wire position with an x-ray first perhaps). Occasionally a CVP line inserted via the left IJ vein will go down the left internal mammary vein; quite how this happens is not clear since the curved tip of the J-wire should prevent the wire from going down a small vessel. The distal lumen in such cases is typically associated with difficult aspiration and poor CVP waveform. Since redirecting a misplaced CVP line can be difficult, consider monitoring the CVP via one of the more proximal lumens—withdrawing the line slightly if necessary—until you see a good CVP waveform. Consequently, always X-ray a left IJ line before considering railroading a Swan-sheath over it. For information and video clips relating to CVP insertion technique see the Clinical Cases web-site (http://clinicalcases.org/).

9.6.4 Anatomy • Albrecht K et al. (2004). Applied anatomy of the superior vena cava—the carina as a landmark to guide central venous catheter placement. Br. J. Anaesth.; 92, 75–77.

• Davidson A, Blumgard C, Paes ML and Enever G (1993). Posture and internal jugular vein size studied with the ‘Siterite’ ultrasound device. Br. J. Anaesth.; 71, 771P. [November issue] [gives a useful table of depth and diameter of the vein for various amounts of head tilt. My own working of their data gives the mean depth of the middle of the vein as 1 64 cm, which is equivalent to a distance of 2 3 cm at 45 degrees to the skin] · · 42I have not tried this as yet, but it seems as though it ought to work. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Daseler EH and Anson BJ (1959). Surgical anatomy of the subclavian artery and its branches.Surg. Gynecol. Obstet.; 108, 149–174. • Galloway S and Bodenham A (2003). Ultrasound imaging of the axillary vein— anatomical basis for central venous access. Br. J. Anaesth., 90, 589–595. • Mathers LH, Smith DW and Frankel L (1992). Anatomic considerations in placement of central venous catheters. Clinical Anatomy; 5, 89–106. • Pahwa R and Kumar A (2003). Persistent left superior vena cava: an intensivist’s experience and review of the literature. Southern Medical Journal; 96, 528–529. [see example CXR on the http://www.learningradiology.com/ website (search for ‘persistent left superior vena cava’)] • Latto IP, Ng WS, Jones PL and Jenkins BJ [Eds.] (2000). Percutaneous central venous and arterial catheterisation; 3rd ed, (W. B. Saunders Company Ltd., London, UK). • Schummer W, Schummer C and Frober¨ R (2003). Internal jugular vein and anatomic relationship at the root of the neck. Anesthesia and Analgesia; 96, 1540. • Schummer W, Schummer C and Geold M (2002). Persistent left superior vena cava: clinical implications for central venous cannulation. American Society for Parenteral and Enteral Nutrition; 17, 304–308. • Sulek CA, Gravenstein N, Blackshear RH and Weis L (1996). Head rotation during internal jugular vein cannulation and the risk of carotid artery puncture. Anesthesia and Analgesia; 82, 125–128. [keeping the head in the midline position reduces the incidence of carotid artery puncture]

9.6.5 Position of CVP tip • Albrecht K et al. (2004). Applied anatomy of the superior vena cava—the carina as a landmark to guide central venous catheter placement. Br. J. Anaesth.; 92, 75–77. • Chalkiadis GA and Goucke CR (1998). Depth of central venous catheter insertion in adults: an audit and assessment of a technique to improve tip position. Anaesthesia and Intensive Care; 26, 61–66. [they used the subclavian method—their tailored technique (8 cm distal from the tip of needle) gave a mean distance from the skin of 13 2 cm (range: 11 5–15 cms; n=73)] · · • Rath GP, Bithal PK, Toshniwal GR, Prabhakar H and Dash HH (2009). Saline ﬂush test for bedside detection of misplaced subclavian catheter into ipsilateral internal jugular vein. Br. J. Anaesth., 102, 499–502. • Ryu H-G, Bahk J-H, Kim J-T and Lee J-H (2007). Bedside prediction of the central venous-catheter insertion depth. Br. J. Anaesth., 98, 225–227. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

9.6.6 General • Chalkiadis GA and Goucke CR (1998). Depth of central venous catheter insertion in adults: an audit and assessment of a technique to improve tip position. Anaesthesia and Intensive Care; 26, 61–66. [they used the subclavian method—their tailored technique (8 cm distal from the tip of needle) gave a mean distance from the skin of 13 2 cm (range: 11 5–15 cms; n=73)] · · • Fukazawa K, Aguina L and Pretto E (2010). IMAGESINANESTHESIOLOGY: Internal jugular valve and central placement. Anesthesiology; 112, 979. • Kayal RD, Salloum LJ, Snyder AB and Barone JE (1989). A simple method of repositioning the wayward central catheter. Journal of Parenteral and Enteral Nutrition; 13, 438–439. • Kitagawa N et al. (2004). Proper shoulder position for subclavian venepuncture. Anesthesiology; 101, 1306–1312. [evidence from CT studies suggests that best position is with the shoulder pushed inferiorly] • Messahel FM and Al-Mazroa AA (1992). Cannulation of the internal jugular vein; the very high approach. Anaesthesia; 47, 842–844. • Nandwani N, Fairﬁeld MC, Krarup K and Thompson J (1997). The effect of laryngeal mask airway insertion on the position of the internal jugular vein. Anesthesia; 52, 77–83. [no lateral movement, but perhaps some slight anterior movement 0 6–1 1 cm, mean 0 8 cm] · · · • Ng PK, Ault MJ and Maldonaldo LS (1996). Peripherally inserted central catheters in the intensive care unit [review]. J. Intensive Care Medicine; 11, 49–54. • Oropello JM, Leibowitz AB, Manasia A, Guidice RD and Benjamin E (1996). Dila- tor associated complications of central vein catheter insertion: possible mechanisms of injury and suggestions for prevention. Journal of Cardiothoracic and Vascular Anesthesia; 10, 634–637. • Pattnaik SK and Bodra R (1999). Another ‘whoosh’ test. Anaesthesia; 54, 1224– 1225. [they describe gradually withdrawing the the malpositioned central line while listening for the disappearance of the distal ‘whoosh’ sound (caused by ﬂushing it with saline) with a stethoscope over the vein. Also list other useful references on this theme (6 refs)]. • Latto IP, Ng WS, Jones PL and Jenkins BJ [Eds.] (2000). Percutaneous central venous and arterial catheterisation; 3rd ed, (W. B. Saunders Company Ltd., London, UK). • Sha K et al. (1998). Use of transoesophageal echocardiography probe imaging to guide internal jugular vein cannulation. Anesthesia & Analgesia, 87, 1032–1033. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Stickle BR and McFarlane H (1997). Prediction of a small internal jugular vein by external jugular vein diameter. Anaesthesia, 52, 220–222. [if the external jugular vein is greater than 7 mm diam, then the internal jugular vein is likely to have a diameter less than 7 mm, and so may be difﬁcult to ﬁnd]

• Tripathi M, Dubey PK and Ambesh SP (2005). Direction of the J-tip of the guidewire in Seldinger technique is a signiﬁcant factor in misplacement of subclavian vein catheter: a randomised controlled study. Anesthesia and Analgesia; 100, 21–24. • Tripathi M and Tripathi M (1996). Subclavian vein cannulation: an approach with deﬁnite landmarks. Ann. Thoracic Surgery; 61, 238–240.

• Willeford KL and Reitan JA (1994). Neutral head position for placement of internal jugular vein catheters. Anaesthesia; 49, 202–204. • Williamson RM and Werstler E (2006). Central line in patients with AV ﬁstula. Anaesthesia; 61 (August), 819-820. [describes confusion with the sampled blood gases in a renal patient with a left-arm dialysis ﬁstula]

9.6.7 Ultrasound guided • Chapman GA, Johnson D and Bodenham AR (2006). Visualisation of needle position using ultrasonography. Anaesthesia; 61, 148–158.

• Fukazawa K, Aguina L and Pretto E (2010). IMAGESINANESTHESIOLOGY: Internal jugular valve and central placement. Anesthesiology; 112, 979. • Galloway S and Bodenham A (2003). Ultrasound imaging of the axillary vein— anatomical basis for central venous access. Br. J. Anaesth., 90, 589–595.

• Habib FA and McKenney MG (2004). Surgeon-performed ultrasound in the ICU setting. Surgical Clinics of North America; 84, 1151–1179. [see section on CVP line placement 1165–1166, with screen images] • Hall AP and Russell WC (2005). Towards safer central venous access: ultrasound guidance and sound advice. Anaesthesia; 60, 1–4. [see also correspondence from Reavley P (2005)] • Hatﬁeld A and Bodenham A (2005). Ultrasound for central venous access. Continu- ing Education in Anaesthesia, Critical Care & Pain; 5, 187–190. • National Institute for Clinical Excellence (NICE) (2002). Guidance on the use of ultrasound locating devices for placing central venous catheters. Technology Appraisal Guidance No. 49 (September 2002); 24 pp. http://guidance.nice. org.uk/TA49/Guidance/pdf/English CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Riopelle JM, Ruiz DP, Hunt JP et al. (2005). Circumferential adjustment of ultrasound probe position to determine the optimal approach to the internal jugular vein: a noninvasive geometric study in adults. Anesth. Analg.; 100, 512–519. • Scott DHT (2004). The king of the blind extends his frontiers. Br. J. Anaesth.; 93, 175–177. [editorial on ultrasound-guided techniques]

9.6.8 External jugular vein If the external jugular vein distends on head-down position, then a Venﬂon in this site adequately reﬂects CVP providing the chest is not open. Placing a central catheter via this route has a high failure rate.

• Blitt CD, Wright WA, Petty WC and Webster TA (1974). Central venous catheterisation via the external jugular vein. A technique employing the J-wire. JAMA; 229, 817. • Briscoe CE (1973). A comparison of jugular [external] and central venous pressure measurement during anaesthesia. Br. J. Anaesth.; 45, 173.

• Dailey RH (1988). External jugular vein cannulation and its use for CVP monitoring. Journal of Emergency Medicine; 6, 133. • Shah MV, Swai EA and Latto IP (1986). Comparison between pressures measured from the proximal external jugular vein and a central vein. Br. J. Anaesth.; 58, 1384.

9.6.9 Axillary vein • Andel H, Rab M, Felfernig M et al. (1999). The axillary vein central venous catheter in severely burned patients. Burns; 25, 753–756.

• Galloway S and Bodenham A (2003). Ultrasound imaging of the axillary vein— anatomical basis for central venous access. Br. J. Anaesth., 90, 589–595. • Levine E and Budzikowski AS (2009). Catheterisation, axillary vein. http://emedicine.medscape.com/article/1348912-overview http://emedicine.medscape.com/article/1348912-media http://emedicine.medscape.com/article/1348912-treatment (other related procedures are at: >clinical procedures>vascular) Accessed May 2010. − • Nickalls RWD (1987). A new percutaneous infra-clavicular approach to the axillary vein. Anaesthesia; 42, 151–154. http://www.nickalls.org/dick/papers/ anes/axillaryvein1987.pdf CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Restrepo Valencia CA (2008). Axillary catheter for hemodialysis, an alternative vascular access. Nefrologia;, 28, 77–81. • Sandhu NS (2004). Transpectoral ultrasound-guided catheterization of the axillary vein: an alternative to standard catheterization of the subclavian vein. Anesthesia and Analgesia; 99, 183–187. • Sharma A, Bodenham AR and Mallick A (2004). Ultrasound-guided infraclavicular axillary vein cannulation for central venous access. Br. J. Anaesth.; 93, 188–192. • Taylor BL and Yellowlees I (1990). Central venous cannulation using the infraclavicular axillary vein. Anesthesiology; 72, 55.

9.6.10 Femoral vein There are many papers in the literature showing that CVP is accurately reﬂected by inferior vena cava and common iliac venous pressure measurements in supine patients (both adult and paediatric), providing the transducer is zeroed at the usual right-atrial level on the mid-axillary line. Measurements of inferior vena cava pressures seem to be approximately 0 5 mm Hg lower than superior vena cava pressures on average, and rarely more than 3·mm Hg different, even in patients with high PEEP or raised mean airway pressures (Desmond 2003). Femoral CVP results may be less accurate in patients with signiﬁcantly raised intra-abdominal pressure [the references below are from Desmond (2003)].43 • Chait HI, Kuhn MA, Baum VC (1994). Inferior vena caval pressure reliably predicts right atrial pressure in pediatric cardiac surgical patients. Crit. Care Med.; 22, 219–24. • Desmond J (2003). Is the central venous pressure reading equally reliable if the central line is inserted via the femoral vein? http://www.bestbets.org/ (search under ‘author’) • Ho KM, Joynt GM, Tan P. (1998). A comparison of central venous pressure and common iliac venous pressure in critically ill mechanically ventilated patients. Crit. Care Med.; 26, 461–4. • Nahum E, Dagan O, Sulkes J, et al. (1996). A comparison between continuous central venous pressure measurement from right atrium and abdominal vena cava or common iliac vein. Intensive Care Med.; 22, 571–4. • Joynt GM, Gomersall CD, Buckley TA, et al. (1996). Comparison of intrathoracic and intra-abdominal measurements of central venous pressure. Lancet; 347, 1155–7. • Walsh JT, Hildick-Smith DJ, Newell SA, et al. (2000). Comparison of central venous and inferior vena caval pressures. Am. J. Cardiol.; 85, 518–20.

43I thank Dr Mofolashade Enebeli-Cliffe for drawing my attention to many of these references. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

9.6.11 Complications These are mostly related to air embolism, vessel damage from needle or dilator or kinked guide-wire, introducing the guide-wire outside the vessel, catheter knotting, dysrhythmias, pneumothorax and cardiac tamponade. Unusual anatomy 44 and failure to use ultrasound visualisation appear to be prominent factors in many complications (see Section 9.6.4).

Guide-wire problems The guide-wire is easily kinked, and once kinked it can not be straightened and can easily damage/tear the vein if introduced into it. A simple test to check for such kinking while trying to advance the dilator (over the wire) is to intermittently check that you can slide the wire back and forth (say, 1 cm or so) inside the introducer. Any difficulty in sliding the wire back and forth is a good± sign that the wire may have become kinked—in which case withdraw the guide-wire carefully to bring the kink to the skin for inspection. In my experience, the guide-wire is most easily damaged/kinked when using the femoral approach in fat patients, since in these cases one often has to press the Sonosite probe down quite firmly (and hence distort the subcutaneous tissue) in order to see the vein clearly. The kinking of the guide-wire usually occurs while trying to introduce the dilator through the subcutaneous tissue, since in fat patients the path of the guide-wire here becomes quite curved into a sigmoid shape once the Sonosite probe is removed.45 In my experience in this setting, it is best to have an assistant replace the Sonosite probe and press down as before (i.e., to straighten the subcutaneous path of the guide-wire) while introducing the dilator. If a dialysis catheter guide-wire does become kinked in a difficult case, it is often possible to rescue the situation and exchange it safely, since the guidewire will generally still be in the vein even when pulled back slightly to bring the kink to the skin 46. The idea is to first railroad an ordinary CVP line over the wire and into the vein (ie., with the kink still showing just above the skin), replace the damaged guide-wire with a new dialysis catheter guide-wire, then remove the CVP line, and then continue with the dialysis line as before. • Dhanani J, Senthuran S, Olivotto R, Boots RJ and Lipman J (2007). The entrapped central venous catheter. Br. J. Anaesth.; 98, 89–92. [a new catheter pierced an existing catheter in the same vein; interventional radiology used for diagnosis and determination of a removal strategy; the literature is reviewed; 11 refs]

• Lobato EB, Gravenstein N and Paige GB. (1997). Dilator-associated complications

44Persistence of the left superior vena cava (LSVC)—which is asymptomatic—is thought to be the most common anomaly of the venous circulation and can be a signiﬁcant hazard with regard to CVP line placement (see paper by Schummer, Schummer and Gerald (2002) listed in Section 9.6.4). 45Since the guide-wire is initially introduced via a straight needle, its path to the vein will only remain straight (after removing the needle) while the Sonosite probe is pressing down over the vein. 46It is therefore, a good idea to introduce plenty of guide-wire into the vein before starting to thread the dilator. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

of central vein catheter placement: possible mechanisms of injury and suggestions for prevention. Journal of Cardiothoracic and Vascular Anesthesia; 11, 539. • Muhn M, Sunder-Plassmann G and Druml W (1996). Malposition of a dialysis catheter in the accessory hemiazygos vein. Anesthesia and Analgesia; 83, 883–885. • Oropello JM, Leibowitz AB, Manasia A, Guidice RD and Benjamin E (1996). Dilator-associated complications of central vein catheter placement: possible mechanisms of injury and suggestions for prevention. Journal of Cardiothoracic and Vascular Anesthesia; 10, 634–637. • Jiha JG, Weinberg GL and Laurito CE (1996). Intraoperative cardiac tamponade after central venous cannulation. Anesthesia and Analgesia; 82, 661–665. • Scott WL and Collier P (2001). The vessel dilator for central venous catheter placement: forerunner for success or vascular misadventure? Journal of Intensive Care Medicine; 16, 263–269.

9.7 Pulmonary artery catheter

9.7.1 History Michael Lategola and Hermann Rahn Balloon-flotation pulmonary artery catheters were first used by the American physiologists Lategola and Rahn for pressure recording, blood sampling and vessel occlusion in experiments with dogs (Lategola and Rahn 1953). Since their balloon covered the distal tip they were only able to measure pressures proximal to the occluded vessel. Thermodilution cardiac output was first described in animals the following year (Fegler 1954).

Ronald Bradley The ﬁrst person to describe the use of a pulmonary-artery catheter in man was Ronald Bradley, a physician at St. Thomas’ Hospital, London (Bradley 1964). He used an extremely narrow catheter (0 63 mm diam) having no balloon, to determine pulmonary artery pressures and waveforms,· and later went on to determine thermodilution cardiac output in man using a thermistor-tipped catheter (Branthwaite and Bradley 1968), and suggested the use of PA-diastolic pressure as an index of mean left-atrial pressure (Jenkins, Bradley and Branthwaite 1970). Bradley also wrote an excellent book on the physiology of heart failure (Bradley 1977).

Harold Swan and William Ganz Bradley’s catheters had no balloon and were extremely difﬁcult to position, and so the technique remained clinically impractical until Swan et al. (1970) developed the modern CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

balloon-ﬂotation catheter. Since Swan wished to determine left atrial pressure he arranged that pressures could be measured distal to the balloon. Oddly enough Swan fails to credit Bradley and Branthwaite (1968) with the thermodilution technique in man—instead he credits this to Ganz (Swan 1991). Swan (1922–2005) graduated from St. Thomas’ Hospital Medical School, London, in 1945, and went on to become the Director of the Division of Cardiology at Cedars-Sinai Medical Center in Los Angeles, California. He has set on record the key early ideas and development of the ﬂow-directed balloon-tipped catheter (Swan 1991; 2005) as follows.

In 1950 as a lecturer in physiology at St. Thomas’ Hospital of the University of London, I had come to know a young medical student, Ronald Bradley, who was completing a bachelor’s degree in physiology. I had noted a paper published in the Lancet (Bradley 1964), in which Bradley had claimed that it was possible to catheterize the pulmonary artery for measurement of pressures using an extremely fine Portex tubing . . . and I therefore attempted to place it. . . . In our hands this approach had little success . . . In the fall of 1967, I had the occasion to take my (then young) children to the beach in Santa Monica. On the previous evening, I had spent a frustrating hour with an extraordinary pleasant but elderly lady in an unsuccessful attempt to place one of Bradley’s catheters. It was a hot Saturday and the sailboats on the water were becalmed. However, approximately half a mile offshore, I noted a boat with a large spinnaker well set and moving through the water at a reasonable velocity. The idea then came to to put a sail or a parachute on the end of a highly flexible catheter and thereby increase the frequency of passage of the device into the pulmonary artery. I felt convinced that this approach would allow for the rapid and safe placement of a flotation catheter without the use of fluroscopy and would solve the problem of arrhythmias. . . . I had been appointed a consultant to the Edwards Laboratories, then a small manufacturing company whose products included the Starr-Edwards heart valve and the Fogarty embolectomy catheter. . . . I brought my concept to the attention of Mr David Chonette and Mr Will Perrie. They had the facilities for extrusion of catheters of different sizes . . . To test the concept, however, they had the ability to manufacture balloons (as for the Fogarty catheter) and suggested that, as a first effort, a double- lumen extruded catheter should be manufactured with one lumen available to inflate a flotation balloon. This proved to be acceptable and they agreed to fabricate five such catheters. . . . As luck would have it, when the Edwards Laboratories delivered their first catheters, Willie [Ganz] was finishing an experiment with his animal in good condition. I brought the prize catheters to the laboratory and connected the pressure lumen to an appropriate strain gauge manometer. The catheter was then introduced via the exposed jugular vein into the right atrium and, observing with fluroscopy, the balloon was inflated. It immediately disappeared, and the technician reported no change in the recorded pressure. I immediately assumed an inadequacy of balloon tensile strength and mentally blamed faulty construction by the Edwards Laboratory. However, repeat visualization revealed that the catheter had migrated in one heartbeat through the right heart and was recording the wedge pressure in a distal pulmonary artery. Deflation of the balloon allowed its prompt return to the superior vena cava. . . . Willie Ganz accepted the CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

responsibility of clearing up the many technical details, but the concept was proved and the new device was born. . . . A triple-lumen catheter allowed measurement of simultaneous pressures in the wedge position (the pulmonary occluded pressure) and in the right atrium. With a slight modiﬁcation, a thermistor was inserted close to the guiding balloon and the thermodilution technique of Willie Ganz (Ganz et al. 1971) for determination of cardiac output was applied. Swan (1991)

Swan (1922–2005) died on 7th February, 2005, and his last paper (Swan 2005) appeared in the October 2005 issue of Anesthesiology. A photograph of Swan can be found on the Anesthesiology web site.47

• Achan V (1999). Another European view: the origin of pulmonary artery catheterization. Critical Care Medicine; 27, 2850–2851. • Amin DK, Shah PK and Swan HJC (1986). The Swan-Ganz catheter: choosing and using the equipment. Journal of Critical Illness; 1, 34–37.

• Amin DK, Shah PK and Swan HJC (1986). The Swan-Ganz catheter: insertion technique. Journal of Critical Illness; 1, 38–45. • Amin DK, Shah PK and Swan HJC (1986). The Swan-Ganz catheter: tips on interpreting results. Journal of Critical Illness; 1, 40–48. • Amin DK, Shah PK and Swan HJC (1986). The Swan-Ganz catheter: indications for insertion. Journal of Critical Illness; 1, 54–61. • Bradley RD (1964). Diagnostic right-heart catheterisation with miniature catheters in severely ill patients. Lancet; 2, 941–942. • Bradley RD (1977). Studies in acute heart failure. (Edward Arnold Ltd., London). ISBN 0–7131–4295–2, 76 pp. • Branthwaite MA and Bradley RD (1968). Measurement of cardiac output by thermal dilution in man. J. Applied Physiology; 24, 434–438. • Comroe JH (1977). Retrospectroscope: insights into medical discovery. (Von Gehr Press, Menlo Park, California, USA).

• Fegler G (1954). Measurement of cardiac output in anesthetized animals by a thermodilution method. Quarterly Journal of Experimental Physiology; 39, 153– 164. [from: MacKenzie 2003]

47http://journals.lww.com/anesthesiology/; follow the ‘enhancements index’ link 2005. → CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Ganz W, Donoso R, Marcus HS, Forrester JS and Swan HJC (1971). A new technique for measurement of cardiac output by thermodilution in man. American Journal of Cardiology; 27, 392–396. • Jenkins BS, Bradley RD and Branthwaite MA (1970). Evaluation of pulmonary arterial end diastolic pressure as an indirect estimate of left atrial mean pressure. Circulation; 42, 75. • Lategola M and Rahn H (1953). A self-guiding catheter for cardiac and pulmonary arterial catheterization and occlusion. Proc. Soc. Exp. Biol. Med.; 84 667–668. • Poplausky MR, Rozenblit G, Rundback H et al. (2001). Swan-Ganz catheter-induced pulmonary artery pseudoaneurysm formation: three case reports and a review of the literature. Chest; 120, 2105–2111. • Shaw TJI (1979). The Swan-Ganz pulmonary artery catheter: incidence of complications, with particular references to ventricular dysrhythmias, and their prevention. Anaesthesia; 34, 651–656. [recommends use of lignocaine 1mg/kg IV] • Swan HJC (2005). The pulmonary artery catheter in anesthesia practice. Anesthe- siology, 103, 890–893. [Swan’s ﬁnal paper—includes some interesting historical detail regarding the development of the PA catheter] • Swan HJC (1991). Development of the pulmonary artery catheter. Disease-a- Month; 37 (August), 485–508 (Elsevier). [whole of this classic issue (p. 478–543) is devoted to the Swan-Ganz catheter, including a reprint of the excellent four- part series by Amin, Shah and Swan (1986) listed below. Available on-line via http://www.sciencedirect.com/ & also via the ATHENS internet database] • Swan HJC, Ganz W, Forrester J, Marcus H, Diamond G and Chonette D (1970). Catheterization of the heart in man with use of a ﬂow-directed balloon-tipped catheter. New England Journal of Medicine; 283, 447–451.

9.7.2 Decline in use In recent years the use of pulmonary artery catheters has declined somewhat, partially owing to lack of good evidence that it improves outcome (ESCAPE committee 2005; Shah et al. 2005; Hall 2005), and partly owing to new non-invasive cardiac output monitoring devices (e.g., PiCCO, LiDCO, oesophageal doppler).

• ASA (2003). Practice guide-lines for pulmonary artery catheterisation: an updated report by the American Society of Anesthesiologists Task Force on pulmonary artery catheterisation. Anesthesiology; 99, 988–1014.

• ESCAPE committee (2005). Evaluation study of congestive heart failure and pulmonary artery catheter effectiveness: the ESCAPE trial. JAMA; 294, 1625–1633. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Hall JB (2005). Searching for evidence to support pulmonary artery catheter use in critically ill patients. JAMA; 294, 1693–1694.

9.8 Computers & information technology

The first anaesthetic machine to incorporate a microprocessor was in 1976 (Katz 2006), and since then computers have progressively influenced anaesthesia delivery and patient safety. One of the next major influences on anaesthesia practice is likely to be related to data processing, particularly in the areas of smart alarms and decision support. While development and take-up in the operating theatre is almost imperceptible just now, the future surely lies in computers offering anaesthetists seriously useful facilities. The initial motivation with regard to data handling lay in automating the anaesthesia record. However, while this technology has been effectively solved for over 15 years (see Kenny 1990), the take-up by anaesthetists in the UK remains almost zero.

9.8.1 History of the anaesthesia record The documentation of events, procedures undertaken, physiological parameters (vital signs) which are associated with the process of anaesthesia (for example, in conjunction with surgery or an intensive care setting) is known as the Anaesthesia Record. This record serves two main functions, namely (a) medical (the moment-to-moment drug history and vital-signs serves as a useful practical aid), and (b) medico-legal (the anaesthesia record is a legal document in its own right, setting out the facts as they unfold during an anaesthetic).

Background Effective surgical anaesthesia using inhaled diethyl-ether (“ether”) was ﬁrst established in 1842 by Crawford Long (1815–1878) in a handful of unpublicised cases. Some four years later in 1846 ether anaesthesia was rediscovered and popularised by William Morton (1819–1868), who gave a public demonstration on 16th October 1846 at the Massachusetts General Hospital (Boston, USA). Subsequently, John Snow (1813–1858), Joseph Clover (1825–1882), and Mounier (1855) demonstrated the importance of monitoring the pulse and respiration during anaesthesia (Ellis 1995; Rushman, Davies and Atkinson 1996), but it was not until 1894, at the Massachusetts General Hospital, Boston, that surgeons Ernst A Codman (1869–1940) and Harvey Cushing (1869–1939) established the practice of keeping a careful written record (on graph paper) of the patient’s pulse and respiration rate during operations—known as the ‘ether chart’ (Beecher 1940; Hirsch and Smith 1986). Apparently this was prompted by a death under anaesthesia in 1893 (Rushman, Davies and Atkinson 1996, p. 128). In 1901 they started including measurements of the arterial blood pressure using the newly described apparatus of Scipione Riva-Rocci (1863–1937) of Turin (Cushing 1902; Cushing 1903; Rushman, Davies and Atkinson 1996, p. 157). CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

Ralph Waters (1936; 1942) championed and emphasised the importance of written anaesthetic records, and later Noseworthy (1945) produced special cards on which to record anaesthetic details (see Rushman, Davies and Atkinson 1996, p. 111, for an illustration).

Automation An automated anaesthesia record is significantly superior to the usual hand-written record, since it samples data much more frequently and more accurately, and hence it has significant medico-legal advantages regarding the documentation of patient care, particularly during complicated and/or unstable cases. The first mechanical device capable of printing an anaesthetic record was the Nargraf machine of 1930 developed by EI McKessons (Westhorpe 1989), which generated a semi-automated record of inspired oxygen, tidal volume and inspiratory gas pressure. After this little of real technological significance was developed in the area of anaesthesia monitoring until the 1970s, when advances in chip technology gave rise to clinically useful portable electronic devices for measuring such things as arterial and central venous blood pressure, breath-by-breath concentrations of oxygen, carbon dioxide and inhalational anaesthetics, pulse oximetry, and of course, small computers. From an interfacing point of view, a very significant and far reaching feature was incorporated into virtually all early medical monitoring devices, namely a specialised serial communications interface known as the RS-232 port.48 Equally significant, therefore, was the decision by IBM to incorporate the RS-232 port into the IBM Personal Computer which appeared in 1981. Fortunately all IBM-compatible PCs since then have also incorporated the RS-232 serial port. Owing to the widespread use of the RS-232 interface in medical equipment it soon became a relatively easy matter to use a PC to access the numerous measured and derived parameters output by patient monitoring devices, and consequently anaesthetists increasingly explored methods for automating data collection and processing, with a view to developing useful trend displays of measured data, real-time calculation of derived parameters, and hard-copy data printouts. The RS-232 interface is likely to be replaced at some stage by the Medical Interface Bus (MIB; IEEE-1073). This is a high-tech high-speed medical plug-and-play version of the familiar domestic USB interface, and will greatly facilitate medical device inter-connectivity, largely by allowing the relevant interface software to be more easily standardised.

Guidelines The Royal College of Anaesthetists has published a summary of what data ought to be collected (in addition to the electronic data from the anaesthesia monitors) as part of the

48The Electronic Industries Association Recommended Standard 232. In 1986 the prefix RS was superceded by the prefix EIA. In 1988 the Telecommunications Industry Association (TIA) was formed by the merger of the US Telephone Suppliers Association and EIA/ITG, and subsequent documents are therefore prefixed by EIA/TIA. The 1991 revision was EIA/TIA-232-E. (Nickalls and Ramasubramanian 1995). CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

Anaesthesia Record (Adams 1996), building on the work of Lack et al. (1994). The extent to which these guidelines are actually being met has also been looked at (Smith 1997). The required record set which appears to be emerging, consists of a number of ﬁelds within the following general categories: pre-, per- and postoperative information, untoward events and hazard ﬂags.

9.8.2 The anaesthesia workstation It is clear that computerisation, both in the operating theatre and in ITU, has the potential to free anaesthetists and nurses from much of the work of documentation (e.g., drug doses, procedures, measured parameters etc.), releasing significant amounts of time which is better spent on direct patient care. Anaesthesia Information Management Systems (AIMS) which incorporate sophisticated record-keeping systems clearly offer the advantage of allowing the anaesthetists to concentrate fully on the patient, leading to enhanced vigilance and improved patient care and safety. Much work has gone into studying the anaesthetists’s workload (Weinger et al. 1997; Byrne, Sellen and Jones 1998; Leedal and Smith 2005). For example, Kennedy et al. (1976) showed that anaesthetists commonly spend 10–15 % of their time producing the handwritten record. Similarly, Smith (1997) pointed out that about 10 % of the anaesthetists’ time was related to record keeping, and that if this were to increase then this would likely be to the patient’s detriment. A similar study by Wong et al. (2003) showed that an ICU information system reduced the time spent by nurses on documentation by 31 %, with the significant benefit being that almost half of the time saved was transferred to patient assessment and direct patient care. Secondary data processing by anaesthetists in the UK is well behind other countries, with electronic data collection being actively supported by foreign health organisations. For example, in 2001 the ‘summer’ newsletter of the Anesthesia Patient Safety Foundation (APSF) was devoted to Information systems in anaesthesia (Thys, 2001). In 2002 the APSF formally endorsed the use of automated anesthesia information management systems (AIMS) as the following quote indicates.

In this context it is heartening that the . . . APSF has recently endorsed the use of automated anesthesia information management systems (AIMS): “The Anesthesia Patient Safety Foundation endorses and advocates the use of automated record keeping in the perioperative period and the subsequent retrieval and analysis of that data to improve patient safety.” Gage (2002)

Anaesthetists urgently need to harness the power of computing technology in a way which can help both in the operating theatre and in the clinic, most likely via some form of anaesthesia workstation. While such systems will probably be commercial, this is not necessarily the only route. Providing anaesthetists take some interest in the details, it is quite possible for useful systems to be developed along the Open Source model, as for CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

example, the immensely successful Linux operating system, and the excellent software tools TEX, LATEX, Perl and others. The emphasis for such a workstation needs to be on helping the anaesthetist give a safe anaesthetic during difficult circumstances. It would access data from a range of sources via the Medical Interface Bus (e.g., anaesthesia monitors, HIS) and then process the data in various ways; for example, generating the anaesthesia record, offering smart alarms, decision support and predictive physiological and pharmacokinetic modelling, as well as enabling data export, data storage and emergency communications. For a long time now, even with a modest PC, it has been a simple matter to access high quality data from anaesthesia monitors (Nickalls and Ramasubramanian 1995; Nickalls 1998, Nickalls, Dales and Nice 2010) and create excellent anaesthesia records offering medico-legal security. These are relatively straightforward to write and get up and running, as, for example, the graphic record shown in Figure 8.1 (page 135) generated by the author’s open-source anaesthesia workstation software.49 With little additional work a theatre-based PC can also display warnings, equipment status information and value- added parameters; for example, real-time age-corrected MAC (Nickalls and Mapleson 2003), smart diabetes monitoring & management, as well as extensive general and drug information support (see Figure 9.5, page 159). Although there has been widespread uptake of AIMS technology by anaesthetists, it is clear that the optimum interface design to facilitate easy and intuitive use is difficult to achieve. Interface design must minimise keyboard/mouse entries by the anaesthetists while maximising information display. All too often the user interface is awkward to use with the effect that time is wasted and data collection is incomplete (Driscoll et al., 2007). However, since anaesthesia practice is much the same the world over, it is to be expcted that with sufficient computer-engineering research an optimum and intuitive interface will emerge given time. A typical example of current progress in making practical automated anaesthesia records and the involvement of XML is that described by Meyer-Bender et al. (2010). The wider adoption of AIMS technology also has the potential to bring about a significant reduction of intraoperative awareness (Nickalls and Mahajan 2010). Of course commercial AIMS technology is available and can be extremely useful (for example, the NarKoData system 50—see Benson et al. 2000, and the Saturn Information System, Drager—see¨ Driscoll et al. 2007), but some can be far from ideal, and relatively unhelpful in facilitating anaesthesia-related activities, or even generating good quality records. These latter failings largely account for the poor take-up of commercial systems by anaesthetists in the UK. That said, improvements are of course being made all the time. Computerisation also offers a significant research benefit. For example, in a study by Muller¨ et al. (2002) anaesthetists were able to search the database of their automated anaesthesia record-keeper and establish useful risk factors predictive of subsequent inotropic support requirement following cardio-pulmonary bypass. Driscoll et al. (2007) used AIMS

49Xenon5; © Nickalls RWD, Dales S and Nice AK (1996–2011) —see Figure 9.5, (page 159) and Figure 8.1 (page 135). 50IMESO, GmbH, Huttenberg, Germany. CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

data to establish underdosage as the cause of awareness in three patients.

Databases Extracting data from big databases requires a good data dictionary (Sanderson and Monk 2003) as, for example, the currently well advanced SNOMED Clinical Terms program (SNOMED-CT),51 which is a dynamic health care terminology infrastructure being developed as part of the NHS National Program for Information Technology (NPfIT). A demonstration program can be accessed from the SNOMED-CT home page. Another NPfIT dictionary database of interest to anaesthetists is the Dictionary of Medicines and Devices (dm+d).52 This consists of a number of coordinated XML-encoded pharmaceutical databases, which also incorporate the associated SNOMED encoding. Of particular interest to anaesthetists is the Virtual Therapeutic Moiety (VTM) database of approximately 2000 ofﬁcial drug names which are to be used henceforth in all European computer interactions relating to drugs. This list is updated frequently and can be downloaded from the website (password required). This useful list was incorporated into the author’s experimental anaesthesia workstation used in the CHN thoracic theatres.

The future The future holds the exciting prospect of developing sophisticated (and possibly Open Source) anaesthesia workstations giving anaesthetists access to good data displays and trends, sophisticated alarms (smart-alarms), real-time predictive modelling for drugs and physiological parameters, information management and decision-support systems (Sanderson, Watson and Russell 2005; Tarassenko, Hann and Young 2006, Berken- stadt et al. 2006). A possible view of the future was presented recently by John, Pe- ter, Chacko et al. (2009). Finally, we note that since 2010 the NHS has been em- bracing the Open Source domain—this can only be a good sign for anaesthetists (see http://www.ehealthopensource.org/).

9.8.3 References • Adams AP (1996). A revised anaesthetic record set. Royal College of Anaesthetists’ Newsletter 27 (1996); 8–9. • Beecher HK (1940). The ﬁrst anesthesia records (Codman, Cushing). Surg. Gynecol. Obstet., 71, 689–693. • Benson M, Junger A, Fuchs C, Quinzio L, Bottger S and Hemplemann G (2000). Use of an anesthesia information management system (AIMS) to evaluate physiologic effects of hypnotic agents used to induce anesthesia. J. Clin. Monit. Comput.; 16, 183–190. 51http://www.ihtsdo.org/snomed-ct/ 52http://www.dmd.nhs.uk/ CHAPTER 9. SUPPORTING TECHNOLOGIES RWD Nickalls 

• Berkenstadt H, Yusim Y, Katznelson R, Ziv A, Livingstone D and Perel A (2006). A novel point-of-care information system reduces anaesthesiologists’ errors while managing case scenarios. European Journal of Anaesthesiology, 23, 239–250. • Byrne AJ, Sellen AJ and Jones JG (1998). Errors on [handwritten] anaesthetic record charts as a measure of anaesthetic performance during simulated critical incidents. Br. J. Anaesth.;80, 58–62. • Cushing HW (1902). On the avoidance of shock in major amputation by cocainiza- tion of large nerve trunks preliminary to their division. With observations on blood pressure changes in surgical cases. Annals of Surgery, 36, 321–345. [from Hirsch & Smith (1986)] • Cushing HW (1903). On routine determinations of arterial tension in operating rooms and clinic. Boston Med. Surg. Journal, 148, 250–256. [from Hirsch & Smith (1986). Reproduced in ‘Classical File’, Survey of Anesthesiology (1960); 4, 419]

• Driscoll WD, Columbia MA and Peterfreund RA (2007). An observational study of anesthesia record completeness using an Anaesthesia Information Management System. Anesthesia and Analgesia; 104, 1454–1461. • Ellis RH (1995). The Casebooks of Dr John Snow. (Wellcome Institute for the History of Medicine); p. 22, p. 30.

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...TEX is potentially the most signiﬁcant invention in typesetting this century. It introduces a standard language in computer typography and in terms of importance could rank near the introduction of the Gutenberg press. Gordon Bell (1979) 1

2 HIS booklet was typeset using the 2010 TEXLive implementation of the open- 3 45 source LATEX system on a PC (Mandriva2006-Linux operating system), and T printed at 300 dpi from PDF files generated using PDFLATEX. The line drawing in 6 Figure 5.1 and the iso-MAC charts were generated using mathsPICPerl. Image manipulation was achieved using standard Open Source utilities, including GIMP, DVIPS, fitps.pl, GhostScript, ps2pdf and epstopdf. The text-editor used was KILE 1.6. The index was compiled automatically using the TEX package makeindex. The ‘hazard’ glyph shown in the margin (used on page 47) was created by the Stan- 7 8 ford computer scientist Donald Knuth and featured prominently in Knuth’s TEX books . This delightful and unusual ‘dangerous-bend’ notation has a curious provenance; it was originally the brain-child of a remarkable and prolific group of mathematicians, known collectively as Bourbaki,9 10 who used a variant form of it to highlight the trickier mathematical sections in their series of books. 1 In the Forword to: Knuth, DE (1979). TEX and METAFONT, new directions in typesetting. (American Mathematical Society and Digital Press, Stanford). 2http://www.tug.org/texlive/ 3The Open Source initiative defines nine requirements which software must comply with in order for it to be regarded as ‘Open Source’—see http://www.opensource.org/docs/definition.html. 4 LATEX is the de facto standard for the production of scientific documents (http://www.tug.org/). 5 For an overview of TEX&LATEX see http://www.nickalls.org/dick/links/rwdnLinks.html#tex 6http://www.ctan.org/tex-archive/graphics/mathspic/perl/ 7DE Knuth. In: Shasha D and Lazere C (1995). Out of their minds: the lives and discoveries of 15 great computer scientists (Copernicus [Springer-Verlag New York]). 8 Knuth DE (1990). The TEXbook, (American Mathematical Society & Addison-Wesley). 9Halmos PR (1957), “Nicolas Bourbaki”. Scientific American, (May issue). 10Aczel AD (2007). The artist and the mathematician: the story of Nicolas Bourbaki, the genius mathematician who never existed, (High Stakes Publishing, London, UK.)

196 Index

Abrams, H, 173 thymectomy, 21 ACTc software, 152 tracheal resection, 21 acute lung injury, 118 use of computers, 187 adrenaline, 127, 128 anaesthesia record Aeby, CT, 61 automation, 188 Aintree intubation catheter, 57 carcinoid case, 135 airway history, 187 difficult problems, 54 anatomy jet ventilation, 54 aberrant bronchus, 66 Allen test, 168 Aeby, CT, 61 history, 168 anatomical terms, 59 modified Allen test, 168 arterial circulation of the hand, 167 anaesthesia Boyden, EA, 62 bronchoscopy, 87 bronchopulmonary segment, 61 carcinoid, 133 carina, 65 computer workstation, 189 central veins, 176, 177 drug database, 191 displaced bronchus, 66 history of anaesthesia record, 187 epidural, 31 lung biopsy, 20 Ewart, W, 61 lung volume reduction, 22 Glass, A, 62 myasthenia gravis, 21 history (lung anatomy), 61 one-lung, 100, 111 Hunter, W, 61 extubation, 116 Kramer, R, 62 management of, 113 lingula, 60 postoperative complications, 116, lung, 59 117 lung embryology, 63 preparation, 112 palmar arches of the hand, 167 returning to two-lungs, 115 right-upper lobe orifice, 66 turning patient supine, 115 supernumerary bronchus, 66 ventilation, 112 Swammerdam, J, 61 patient with tracheostomy, 52 tracheal bronchus, 124 pleurectomy-bilateral, 22 wax models of lung, 61 SNOWMED clinical terms, 191 Aoyagi, T, 144

197 INDEX RWD Nickalls 

APUD, 133 Arndt, 93 Arndt bronchus-blocker, 93 Broviac, JW, 174 arterial line, 166 Bryce-Smith double-lumen tube, 94 history, 166 bupivicaine, 34 systolic pressure variations, 170 atelectasis, 117 camera-mode (bronchoscopy), 86 awareness & MAC, 157 carcinoid, 133 axial rotation of bronchoscope, 85 anaesthesia for, 133 axillary vein, 180 anaesthesia record, 135 central line and, 180 APUD, 133 blood glucose, 134 Baum, S, 173 chlorpheniramine, 134 bending of bronchoscope, 86 HIAA, 133 Bernoulli, D, 166 ketanserin, 133 Bourbaki, N, 196 octreotide, 133 Boyden, EA, 62 ondansetron, 134 Bradley, R, 183 ranitidine, 134 Brock, RC, 59 carina, 65, 80 BronchoCath double-lumen tube, 96 Carlens double-lumen tube, 94 bronchopulmonary segment, 61 Carlens, E, 94, 95 bronchoscopy, 78, 80 Carroll, S, 63 anaesthesia for, 87 catechol, 127 axial rotation of bronchoscope, 85 catecholamines, 127 bending of bronchoscope, 86 central line, 171 camera-mode, 86 Abrams, H, 173 carina, 80 anatomy of central veins, 176 complications, 90 axillary vein, 180 history, 79 Baum, S, 173 Ikeda, S, 79 Broviac, JW, 174 image orientation, 85 complications, 182 intubation, 90 Cournand, A, 172 left subcarina, 81 Dotter, C, 174 local anaesthesia for, 41 external jugular vein, 180 right subcarina, 83 femoral vein, 181 simulators, 80 Forssmann, W, 171 Tyndall, J, 79 general references, 178 venturi jet ventilation, 89 history, 171 bronchus J-wire, 174 aberrant bronchus, 66 optimum position, 176 displaced bronchus, 66 position of tip, 177 supernumerary bronchus, 66 Richards, D, 172 tracheal bronchus, 124 Seldinger, S-I, 172 bronchus blocker, 92, 93 ultrasound guided, 179 INDEX RWD Nickalls 

central veins J-wire, 174 anatomy, 176, 177 position of tip, 177 axillary vein, 180 ultrasound guided, 179 external jugular vein, 180 femoral vein, 181 Darwin, C, 63 chest drains, 24 data sharing, 160 chlorpheniramine, 134 desﬂurane, 155 Clover, J, 187 difﬁcult airway, 54 Codman, EA, 187 displaced bronchus, 66 colophon, 196 dobutamine, 127, 128 complications, 36 dopamine, 128 acute lung injury, 118 Dotter, C, 174 arterial line, 170 double-lumen tube, 94 atelectasis, 117 BronchoCath, 96 epidural abscess, 36 bronchoscopy–left DLT, 106 epidural haematoma, 37 bronchoscopy–right DLT, 109 one-lung anaesthesia, 116, 117 Bryce-Smith, 94 pulmonary oedema, 117, 118 Carlens, E, 94, 95 tracheal damage, 116 checking equipment, 103 tracheal rupture, 116 database, 97 computers, 187 history, 94 anaesthesia record, 187 intubation, 103 drug dictionary/database, 191 optimum method, 101 IBM PC, 188 placing, 101 MAC software, 152 preparation, 102 MIB, 188 railroading, 104 RS-232 port, 188 Robertshaw, FL, 95 SNOWMED clinical terms, 191 stethoscope check, 105 Virtual Therapeutic Moiety (VTM), summary, 102 191 Table of sizes, 96 Corenham, J, 145 TEPID database, 97 Cournand, A, 172 tidal volume and pressure check, 110 Cushing, H, 187 tracheal bronchus, 124 CVP line tracheostomy, 122 anatomy of central veins, 176 turning patient supine, 115 anatomy problems, 182 turning patient laterally, 110 axillary vein, 180 White, GMJ, 95 complications, 182 drugs, 126 external jugular vein, 180 adrenaline, 127, 128 femoral vein, 181 bupivicaine, 34 general references, 178 cardiovascular, 126 guide-wire problems, 182 catechol, 127 catecholamines, 127 INDEX RWD Nickalls 

chlorpheniramine, 134 terlipressin, 127 desflurane, 155 tinzaparin, 37 dictionary/database, 191 TIVA, 87, 139 dilutions, 128 vasopressin, 128 dobutamine, 127, 128 DVT prophylaxis and epidurals, 37 dopamine, 128 enoxaparin, 37 Eger, EI, 150 ephedrine, 126 embryology of lung, 63 fentanyl, 34 empyema, 25 GTN, 128 enoxaparin, 37 haemostatic agents, 138 ephedrine, 126, 127 heparin, 37 epidural, 30 infusions, 128 abscess, 36 isoflurane, 153 anatomy, 31 isoprenaline, 127, 128 awake or GA?, 33 ketanserin, 133 bupivicaine, 34 LMWH, 37 catheter disconnection, 36 metaraminol, 126, 127 database, 32 methoxamine, 126 depth (midline), 32 neostigmine, 21 disconnection, 36 noradrenaline, 127, 128, 130, 131 drugs, 34 octreotide, 133 DVT prophylaxis, 37 ondansetron, 134 fentanyl, 34 phenylephrine, 126, 127 fibreoptic-guided placement, 34 propofol, 87 haematoma, 37 TCI, 87, 88 Huber point, 143 pyridostigmine, 21 Huber, RL, 143 ranitidine, 134 Lee epidural needle, 32, 143, 144 recombinant factor VIIa, 138 Lee, JA, 32, 143, 144 remifentanil, 87, 88, 138 midline, 33 bolus, 138 paramedian, 33 infusion, 139 paravertebral block, 37 MAC equivalent, 139 radiographic placement, 34 TCI, 87, 88, 139 reducing catheter fallout, 34 sevoflurane, 154 TEPID database, 32 single strength dilution, 128 Tuohy needle, 143 SNP, 128 Tuohy, EB, 143 somatostatin analogues, 133 evolution of the lung suxamethonium infusion, 88 Carroll, S, 63 table—single strength dilutions, 128 Darwin, C, 63 table—vasoactive drugs, 126 Ewart, W, 61 TCI, 139 external jugular vein, 180 central line and, 180 INDEX RWD Nickalls 

femoral vein, 181 Cournand, A, 172 central line and, 181 Cushing, H, 187 fentanyl, 34 Dotter, C, 174 fibreoptics double-lumen tube, 94 Tyndall, J, 79 Eger, EI, 150 flail chest, 23 Ewart, W, 61 Forssmann, W, 171 Forssmann, W, 171 Ganz, W, 183 Ganz, W, 183 Glass, A, 62 glass fibres, 79 Gutenberg press, 196 Glass, A, 62 Hales, S, 166 GTN, 128 Harvey, W, 94 Gutenberg press, 196 Head, H, 94 Hooke, R, 94 haemostatic drugs, 138 Huber, RL, 143 recombinant factor VIIa, 138 Hunter, W, 61 Hales, S, 166 Ikeda, S, 79 Harvey, W, 94 Knuth DE, 196 Head, H, 94 Kramer, R, 62 heparin, 37 Lategola, M, 183 HIAA, 133 LATEX, 196 history Leader, S, 42 Abrams, H, 173 Lee, JA, 32, 143, 144 Aeby, CT, 61 Lloyd, J, 145 Allen test, 168 Long, C, 141, 187 Allen, EV, 168 lung anatomy, 61 anaesthesia record, 187 MAC, 146, 150, 151 anatomy of the lung, 61 Mann, H, 142 Aoyagi, T, 144 Mapleson, WW, 151 arterial line, 166 McKessons, EI, 188 Baum, S, 173 modified Allen test, 168 Bernoulli, D, 166 Morton, W, 141, 146, 187 Bourbaki, N, 196 Mounier, CCR, 187 Boyden, EA, 62 Nargraf machine, 188 Bradley, R, 183 New, W, 145 bronchoscopy, 79 Noseworthy, M, 188 Broviac, JW, 174 oximetry, 144 Carlens, E, 94, 95 Pasteur, L, 141 central line, 171 Poiseuille, J-L, 166 Clover, J, 187 Portex, 42 Codman, EA, 187 pulmonary artery catheter, 183 computing, 187 pulse oximetry, 144 Corenham, J, 145 INDEX RWD Nickalls 

Rahn, H, 183 ketanserin, 133 Richards, D, 172 knots Riva-Rocci, S, 187 rolling-hitch, 105 Seldinger, S-I, 172 Knuth, DE, 196 serendipity, 142 Kramer, R, 62 Severinghaus, JW, 150 Shaw, R, 144 laryngectomy Snow, J, 141, 146, 187 and tracheostomy, 52 calculation of inhaled %, 149 Lategola, M, 183 temperature effect, 157 LATEX, 196 Swammerdam, J, 61 Leader, S, 42 Swan, H, 183 Lee, JA, 32, 143, 144 TEX, 196 left subcarina, 81 Tuohy, EB, 143 lingula, 60 Tyndall, J, 79 Linux, 196 Walpole, H, 142 Lloyd, J, 145 Waters, R, 188 Long, C, 141, 187 wax models, 61 lung White, GMJ, 95 volume reduction, 22 Hooke, R, 94 anatomical terms, 59 Huber, RL, 143 anatomy, 59 Hunsaker jet ventilation tube, 93 biopsy, 20 Hunsaker tube, 90, 122 embryology, 63 Hunter, W, 61 lung anatomy, 59 history, 61 IBM PC, 188 lung function Ikeda, S, 79 evaluation, 18 image orientation (bronchoscopy), 85 obesity, 20 iso-MAC chart tests, 18 ACTc software, 152 lung volume reduction, 22 desflurane, 155 for download, 152 MAC, 146 isoflurane, 153 ACTc software, 152 MACpalm software, 152 age correction, 151 sevoflurane, 154 awareness, 157 isoflurane, 153 desflurane, 155 isoprenaline, 127, 128 Eger, EI, 150 history, 146 J-wire, 174 iso-MAC chart Jackson-Rees T-piece circuit, 112 desflurane, 155 jet ventilation for download, 152 airway control, 54 isoflurane, 153 tracheostomy, 54 sevoflurane, 154 INDEX RWD Nickalls 

isoflurane, 153 bronchoscopy–right DLT, 109 Lerou nomogram, 152 complications, 116, 117 MACpalm software, 152 extubation, 116 Mapleson, WW, 151 Hunsaker jet ventilation tube, 90, research, 160 122 Severinghaus, JW, 150 intraoperative complications, 116 sevoflurane, 154 Jackson-Rees T-piece circuit, 112 Snow, J, 146 left double-lumen tube, 100 table of MAC data, 152 management of, 113 temperature correction, 157 placing double-lumen tubes, 101 MACpalm software, 152 postoperative complications, 117 Mallinckrodt BronchoCath DLT, 96 preparation, 112 Mann, H, 142 returning to two-lungs, 115 Mapleson, WW, 151 right double-lumen tube, 100 mathsPIC, 196 stethoscope check, 105 McKessons, EI, 188 tidal volume and pressure check, 110 metaraminol, 126, 127 tracheostomy, 122 methoxamine, 126 turning patient laterally, 110 MIB, 188 turning patient supine, 115 modified Allen test, 168 ventilation, 112 Montgomery tracheostomy tube, 54 oximetry Moore tracheostomy tube, 43 Aoyagi, T, 144 Morton, W, 141, 146, 187 history, 144 Mounier, CCR, 187 Nellcor, 145 myasthenia gravis, 21 pulse oximetry, 144

Nargraf machine, 188 paravertebral block, 37 Nellcor, 145 Pasteur, L, 141 neostigmine, 21 percutaneous tracheostomy, 43, 49 Netter images (anatomy), 77 phenylephrine, 126, 127 New, W, 145 pleurectomy-bilateral, 22 nitrous oxide, 23 pneumothorax, 23 cavity expansion, 23 chest drains, 24 noradrenaline, 127, 128, 130, 131 nitrous oxide, 23 Noseworthy, M, 188 surgical emphysema, 25 Poiseuille, J-L, 166 obesity, 20 Portex lung function, 20 history, 42 octreotide, 133 tracheostomy tube, 42 ondansetron, 134 preoperative evaluation, 18 one-lung, 100 cardiac status, 20 anaesthesia, 100, 111 lung status, 18 bronchoscopy–left DLT, 106 propofol, 87 INDEX RWD Nickalls 

TCI, 87, 88 sickle cell disease, 25 pulmonary artery catheter, 183 simulators Bradley, R, 183 bronchoscopy, 80 decline in use, 186 single strength dilution (drugs), 128 Ganz, W, 183 Snow, J, 141, 146, 187 history, 183 calculation of inhaled %, 149 Lategola, M, 183 temperature effect, 157 Rahn, M, 183 SNP, 128 Swan, H, 183 software pulmonary oedema, 118 MAC software, 152 pulse oximetry, 144 somatostatin analogues, 133 history, 144 sternal split, 22 pyridostigmine, 21 supernumerary bronchus, 66 supporting technologies, 141 Rusch¨ double-lumen tube, 43 surgical emphysema, 25 Rusch¨ tracheostomy tube, 43 surgical tracheostomy, 45, 49 radial artery, 167 suxamethonium infusion, 88 ‘harvesting’ of, 168 Swammerdam, J, 61 Rahn, M, 183 Swan, H, 183 ranitidine, 134 syllabus recombinant factor VIIa, 138 advanced-level training, 12 remifentanil, 87, 88, 138 higher-level training, 12 bolus, 138 intermediate-level training, 12 infusion, 139 MAC equivalent, 139 TCI, 87, 88 TCI, 87, 88, 139 propofol, 88 research & data sharing, 160 remifentanil, 88, 139 research & MAC, 160 technology Richards, D, 172 supporting, 141 right subcarina, 83 TEPID database right upper-lobe oriﬁce, 66 epidural database (midline), 32 Riva-Rocci, S, 187 tube database, 97 Robertshaw double-lumen tube, 95 terlipressin, 127 Robertshaw, FL, 95 TEX, 196 rolling-hitch, 105 three princes of Serendip, 142 RS-232 port, 188 thymectomy, 21 tinzaparin, 37 Seldinger, S-I, 172 TIVA, 87, 139 Serendip, three princes of, 142 tracheal bronchus, 124 serendipity, 142 displaced bronchus, 66 Severinghaus, JW, 150 supernumerary bronchus, 66 sevoﬂurane, 154 tracheal damage, 116 Shaw, R, 144 tracheal rupture, 116 INDEX RWD Nickalls 

tracheostomy, 40 jet ventilation (bronchoscopy), 89 Aintree intubation catheter, 57 Virtual Therapeutic Moiety (VTM), 191 air leak, 57 anaesthetising patient with, 52 Walpole, H, 142 changing a tracheostomy, 49 Waters, R, 188 Hunsaker jet ventilation tube, 90, wax models of lung anatomy, 61 122 White, GMJ, 95 inner tube problems, 57 laryngectomy, 52 local anaesthesia for bronchoscopy, 41 miscellaneous problems, 55 Montgomery tube, 54 Moore tube, 43 obstruction, 56 one-lung ventilation, 122 percutaneous, 43, 49 Portex tube, 42 Rusch¨ tube, 43 surgical, 45, 49 recommendations, 45 Table—tube sizes, 50 timing, 43 Tracoe tube, 42 Tracoe tracheostomy tube, 42 tube, 92 database, 97 double-lumen, 92, 94 Hunsaker jet ventilation tube, 93 TEPID database, 97 Univent, 92 Tuohy, EB, 143 turning patient laterally, 110 turning patient supine, 115 Tyndall, J, 79 ulna artery, 167 ‘harvesting’ of, 168 Univent tube, 92 vasopressin, 128 venturi Hunsaker jet ventilation tube, 93