DOCSLIB.ORG

Objectives: Physics I—Physical Laws Upon Completion of the Lecture, The

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Objectives: Physics I—Physical Laws Upon Completion of the Lecture, The Objectives: Physics I—Physical Laws Upon completion of the lecture, the learner will have a working knowledge of: 1. Ideal gas laws a) Boyle's law b) Charles' Law c) Gay-Lussac's Law d) Combined Gas Law e) Avogadro's Hypothesis 2. Diffusion laws a) Pick's Law b) Graham's Law c) Henry's Law d) Dalton's Law 3. Units of Measure a) Metric system b) temperature conversion 4. Solubility coefficients a) blood-gas b) oil-gas c) tissue-gas 5. Physics of the circulatory system a) Ohm's Law b) Hagan-Pouseille equation c) La Place equation Objectives: Physics II—Medical Gases Upon completion of the lecture, the learner will have a working knowledge of: 1. Compressed gas cylinders a)E b) H 2. Oxygen tanks a) capacities b) pressures 3. Nitrous oxide tanks a) capacities b) pressures 4. Air Tanks a) composition b) pressures 5. Pressure relief valves 6. Connectors a) pin index safety system (PISS) 7. Yoke assembly a) contents 8. Proper storage/handling of tanks 9. Central supply of medical gases a) oxygen b) nitrous oxide c) central vacuum system Objectives: Physics III—The Anesthesia Machine Upon completion of the lecture, the learner will have a working knowledge of: 1. The general schematic of the anesthesia machine a) oxygen supply a. tank b. central pipeline i. diameter index safety system (DISS) ii. gauges 1. Bourden principle iii. pressure regulators iv. flush valve v. oxygen supply failure alarm vi. fail-safe valve vii. flow meters 1. construction 2. low and high flows a. gas viscosity vs. density 3. effect of barometric pressure b) Nitrous oxide and air 2. Oxygen ratio monitoring and proportioning systems 3. Common gas outlets/check valves 4. FDA (1993) recommendations for apparatus checkout 5. Vaporizers a) general principles b) vapor, evaporation, and vapor pressure c) minimum alveolar concentration (MAC) d) regulation of output e) variable bypass vaporizers f) effects of changes in barometric pressure g) vaporizer arrangement h) the pumping effect i) the desflurane vaporizer 6. Anesthesia breathing systems a) the circle system i. advantages and disadvantages ii. components a. CO2 absorber 1) chemical reaction b. APL valve c. inspiratory and expiratory valves d. reservoir bag e. circuit hoses f. fresh gas supply b) The Mapleson circuits a. A b. D Objectives: Physics IV—Waste Anesthetic Gases Upon completion of the lecture, the learner will have a working knowledge of: 1. The history and standards of measurement of waste anesthetic gases a) OSHAActof 1970 b) NIOSH recommendations i. halogenated agents ii. nitrous oxide 2. Sources of anesthetic gas spillage a) techniques to reduce OR pollution 3. OR ventilation systems 4. waste scavenging systems a) closed vs. open reservoir i. hoses ii. disposal routes 1. active vs. passive Objectives: Physics V—Ventilators Upon completion of the lecture, the learner will have a working knowledge of: 1. Intermittent positive pressure ventilation (IPPV) a. physiologic dead space b. CO2 production c. O2 consumption d. lung function under IPPV e. types of ventilation i. spontaneous ii. controlled iii. assisted iv. IMV 1. assisted v. airway pressure release ventilation vi. jet ventilation f. machine compliance g. classifications of ventilators i. volume limited ii. pressure limited h. controlled ventilation variables i. minute volume ii. tidal volume iii. inspiratory flow and plateau i. volume ventilators i. bellows ii. control box 1. rate 2. minute volume 3. VT 4. I:E ratio 5. sigh 6. alarma 7. manual cycle j. the ventilatory cycle k. limitations of PPV I. subclasses of ventilators on various anesthesia machines Objectives: Physics VI—Capnography Upon completion of the lecture, the learner will have a working knowledge of: a. types of capnographs i. side stream vs. main stream b. measurement techniques i. infrared vs. mass spectrometry c. the normal capnogram i. 4 phases 1. inspiratory baseline 2. expiratory upstroke 3. expiratory plateau 4. inspiratory downstroke d. the abnormal capnogram i. COPD ii. increased inspiratory resistance iii. rebreathing iv. cardiac oscillations v. "Curare Clefts" e. differences between PaCO2 and PeCO2 Objectives: Physics VII—Oximetry Upon completion of the lecture, the learner will have a working knowledge of: 1. Modes of oxygen transport a) functional saturation (SaO2) b) oxyhemoglobin (O2Hb) c) oxygen content (CaO2) d) oxyhemoglobin dissociation curve 1. Pso e) O2 delivery f) O2 consumption (VO2) 1. Pick equation 2. Physics of the pulse oximeter a) light wavelengths b) blood pulsations c) ratio of O2Hb and RHb 3. Sources of error a) dyes b) COHb and MetHb c) wavelength uncertainty d) signal to noise ratio 1. weak pulses 2. Penumbra effect 3. patient movement 4. venous blood pulsations 5. Bovie interference 4. Accuracy Objectives: Physics VIII—Blood Pressure Monitoring Upon completion of the lecture, the learner will have a working knowledge of: 1. Definition of CO 2. modes of invasive BP monitoring a) waveforms 3. manual BP monitoring 4. oscillometric BP monitoring 5. Penaz technique of BP monitoring 6. Arterial tonometric BP monitoring 7. Pulse transit technique of BP monitoring Objectives: Physics IX—Hazards of the Delivery System Upon completion of the lecture, the learner will have a working knowledge of: 1. causative factors of anesthetic mishaps 2. definition of hypoxia a) causative factors 3. measurement of FiO2 b) O2 analyzers i. O2 galvanic cell ii. polarographic sensors iii. paramagnetic analyzers 4. causes of O2 failure in the anesthesia machine a) upstream b) within the machine or circuit 5. definition of hyperoxia 6. definition of hypercarbia a. causative factors 7. definition of hypocarbia a. causative factors 8. circuit pressure and volume problems 9. anesthetic overdose and underdose 10. electrical failure Objectives: Physics X—Lasers Upon completion of the lecture, the learner will have a working knowledge of: 1. definition of laser 2. medical lasers a. CO2 b. Nd:YAG c. Argon d. KTP e. Dye 3. laser hazards a. ANSI classifications i. ranges 1-4 b. eye damage from lasers 4. considerations during laser surgery of the airway a. ventilation b. ET tubes c. selection of airway gases d. management of airway fires Objectives: Physics XI—Electrical Safety Upon completion of the lecture, the learner will have a working knowledge of: 1. Principles of electricity a. Ohm's law b. power c. electrical work d. impedance e. capacitance f. inductance 2. electrical shock hazards 3. grounded electrical power 4. ungrounded power a. line isolation monitor i. conditions for alarms ii. equipment ground wire iii. ground fault circuit interrupter (GFCI) 5. microshock 6. electrosurgery.
Load more

Recommended publications
  • Respiratory and Gastrointestinal Involvement in Birth Asphyxia
    Academic Journal of Pediatrics & Neonatology ISSN 2474-7521 Research Article Acad J Ped Neonatol Volume 6 Issue 4 - May 2018 Copyright © All rights are reserved by Dr Rohit Vohra DOI: 10.19080/AJPN.2018.06.555751 Respiratory and Gastrointestinal Involvement in Birth Asphyxia Rohit Vohra1*, Vivek Singh2, Minakshi Bansal3 and Divyank Pathak4 1Senior resident, Sir Ganga Ram Hospital, India 2Junior Resident, Pravara Institute of Medical Sciences, India 3Fellow pediatrichematology, Sir Ganga Ram Hospital, India 4Resident, Pravara Institute of Medical Sciences, India Submission: December 01, 2017; Published: May 14, 2018 *Corresponding author: Dr Rohit Vohra, Senior resident, Sir Ganga Ram Hospital, 22/2A Tilaknagar, New Delhi-110018, India, Tel: 9717995787; Email: Abstract Background: The healthy fetus or newborn is equipped with a range of adaptive, strategies to reduce overall oxygen consumption and protect vital organs such as the heart and brain during asphyxia. Acute injury occurs when the severity of asphyxia exceeds the capacity of the system to maintain cellular metabolism within vulnerable regions. Impairment in oxygen delivery damage all organ system including pulmonary and gastrointestinal tract. The pulmonary effects of asphyxia include increased pulmonary vascular resistance, pulmonary hemorrhage, pulmonary edema secondary to cardiac failure, and possibly failure of surfactant production with secondary hyaline membrane disease (acute respiratory distress syndrome).Gastrointestinal damage might include injury to the bowel wall, which can be mucosal or full thickness and even involve perforation Material and methods: This is a prospective observational hospital based study carried out on 152 asphyxiated neonates admitted in NICU of Rural Medical College of Pravara Institute of Medical Sciences, Loni, Ahmednagar, Maharashtra from September 2013 to August 2015.
    [Show full text]
  • Acute Effects of Mechanical Ventilation with Hyperoxia on the Morphometry of the Rat Diaphragm
    ISSN 1413-3555 Rev Bras Fisioter, São Carlos, v. 13, n. 6, p. 487-92, nov./dez. 2009 ARTIGO ORIGIN A L ©Revista Brasileira de Fisioterapia Efeitos agudos da ventilação mecânica com hiperoxia na morfometria do diafragma de ratos Acute effects of mechanical ventilation with hyperoxia on the morphometry of the rat diaphragm Célia R. Lopes1, André L. M. Sales2, Manuel De J. Simões3, Marco A. Angelis4, Nuno M. L. Oliveira5 Resumo Contextualização: A asssistência ventilória mecânica (AVM) prolongada associada a altas frações de oxigênio produz impacto negativo na função diafragmática. No entanto, não são claros os efeitos agudos da AVM associada a altas frações de oxigênio em pulmões aparentemente sadios. Objetivo: Analisar os efeitos agudos da ventilação mecânica com hiperóxia na morfometria do diafragma de ratos. Métodos: Estudo experimental prospectivo, com nove ratos Wistar, com peso de 400±20 g, randomizados em dois grupos: controle (n=4), anestesiados, traqueostomizados e mantidos em respiração espontânea em ar ambiente por 90 minutos e experimental (n=5), também anestesiados, curarizados, traqueostomizados e mantidos em ventilação mecânica controlada pelo mesmo tempo. Foram submetidos à toracotomia mediana para coleta da amostra das fibras costais do diafragma que foram seccionadas a cada 5 µm e coradas pela hematoxilina e eosina para o estudo morfométrico. Para a análise estatística, foi utilizado o teste t de Student não pareado, com nível de significância de p<0,05. Resultados: Não foram encontrados sinais indicativos de lesão muscular aguda, porém observou-se dilatação dos capilares sanguíneos no grupo experimental. Os dados morfométricos do diâmetro transverso máximo da fibra muscular costal foram em média de 61,78±17,79 µm e de 70,75±9,93 µm (p=0,045) nos grupos controle e experimental respectivamente.
    [Show full text]
  • Subacute Normobaric Oxygen and Hyperbaric Oxygen Therapy in Drowning, Reversal of Brain Volume Loss: a Case Report
    [Downloaded free from http://www.medgasres.com on Monday, July 3, 2017, IP: 12.22.86.35] CASE REPORT Subacute normobaric oxygen and hyperbaric oxygen therapy in drowning, reversal of brain volume loss: a case report Paul G. Harch1, *, Edward F. Fogarty2 1 Department of Medicine, Section of Emergency Medicine, University Medical Center, Louisiana State University School of Medicine, New Orleans, LA, USA 2 Department of Radiology, University of North Dakota School of Medicine, Bismarck, ND, USA *Correspondence to: Paul G. Harch, M.D., [email protected] or [email protected]. orcid: 0000-0001-7329-0078 (Paul G. Harch) Abstract A 2-year-old girl experienced cardiac arrest after cold water drowning. Magnetic resonance imaging (MRI) showed deep gray mat- ter injury on day 4 and cerebral atrophy with gray and white matter loss on day 32. Patient had no speech, gait, or responsiveness to commands on day 48 at hospital discharge. She received normobaric 100% oxygen treatment (2 L/minute for 45 minutes by nasal cannula, twice/day) since day 56 and then hyperbaric oxygen treatment (HBOT) at 1.3 atmosphere absolute (131.7 kPa) air/45 minutes, 5 days/week for 40 sessions since day 79; visually apparent and/or physical examination-documented neurological improvement oc- curred upon initiating each therapy. After HBOT, the patient had normal speech and cognition, assisted gait, residual fine motor and temperament deficits. MRI at 5 months after injury and 27 days after HBOT showed near-normalization of ventricles and reversal of atrophy. Subacute normobaric oxygen and HBOT were able to restore drowning-induced cortical gray matter and white matter loss, as documented by sequential MRI, and simultaneous neurological function, as documented by video and physical examinations.
    [Show full text]
  • Short-Time Intermittent Preexposure of Living Human Donors To
    Hindawi Publishing Corporation Journal of Transplantation Volume 2011, Article ID 204843, 8 pages doi:10.1155/2011/204843 Clinical Study Short-Time Intermittent Preexposure of Living Human Donors to Hyperoxia Improves Renal Function in Early Posttransplant Period: A Double-Blind Randomized Clinical Trial Kamran Montazeri,1 Mohammadali Vakily,1 Azim Honarmand,1 Parviz Kashefi,1 Mohammadreza Safavi,1 Shahram Taheri,2 and Bahram Rasoulian3 1 Anesthesiology and Critical Care Research Center, Isfahan University of Medical Sciences, P.O. Box 8174675731, Isfahan 81744, Iran 2 Isfahan Kidney Diseases Research Center (IKRC) and Internal Medicine Department, Alzahra Hospital, Isfahan University of Medical Sciences, P.O. Box 8174675731, Isfahan 81744, Iran 3 Research Center and Department of Physiology, Lorestan University of Medical Sciences, P.O. Box 6814617767, Khorramabad, Iran Correspondence should be addressed to Azim Honarmand, [email protected] Received 6 November 2010; Revised 5 January 2011; Accepted 26 January 2011 Academic Editor: Wojciech A. Rowinski´ Copyright © 2011 Kamran Montazeri et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The purpose of this human study was to investigate the effect of oxygen pretreatment in living kidney donors on early renal function of transplanted kidney. Sixty living kidney donor individuals were assigned to receive either 8–10 L/min oxygen (Group I) by a non-rebreather mask with reservoir bag intermittently for one hour at four times (20, 16, 12, and 1 hours before transplantation) or air (Group II).
    [Show full text]
  • Oxygen Content in Semi-Closed Rebreathing Apparatuses for Underwater Use. Measurements and Modeling
    Doctoral Thesis in Technology and Health Stockholm, Sweden 2015 Oxygen content in semi-closed rebreathing apparatuses for underwater use. Measurements and modeling OSKAR FRÅNBERG KTH ROYAL INSTITUTE OF TECHNOLOGY ENGINEERING SCIENCES Oxygen content in semi-closed rebreathing apparatuses for underwater use. Measurements and modeling OSKAR FRÅNBERG Doctoral thesis No. 6 2015 KTH Royal Institute of Technology Engineering Sciences Department of Environmental Physiology SE-171 65, Solna, Sweden ii TRITA-STH Report 2015:6 ISSN 1653-3836 ISRN/KTH/STH/2015:6-SE ISBN 978-91-7595-616-9 Akademisk avhandling som med tillstånd av KTH i Stockholm framlägges till offentlig granskning för avläggande av teknisk doktorsexamen fredagen den 25/9 2015 kl. 09:00 i sal D2 KTH, Lindstedtsvägen 5, Stockholm. iii Messen ist wissen, aber messen ohne Wissen ist kein Wissen Werner von Siemens Å meta e å veta Som man säger på den Kungliga Tekniska Högskolan i Hufvudstaden Att mäta är att väta Som man säger i dykeriforskning Till min familj Olivia, Artur och Filip iv v Abstract The present series of unmanned hyperbaric tests were conducted in order to investigate the oxygen fraction variability in semi-closed underwater rebreathing apparatuses. The tested rebreathers were RB80 (Halcyon dive systems, High springs, FL, USA), IS-Mix (Interspiro AB, Stockholm, Sweden), CRABE (Aqua Lung, Carros Cedex, France), and Viper+ (Cobham plc, Davenport, IA, USA). The tests were conducted using a catalytically based propene combusting metabolic simulator. The metabolic simulator connected to a breathing simulator, both placed inside a hyperbaric pressure chamber, was first tested to demonstrate its usefulness to simulate human respiration in a hyperbaric situation.
    [Show full text]
  • Hyperoxia Induces Glutamine-Fuelled Anaplerosis in Retinal Mã¼ller Cells
    ARTICLE https://doi.org/10.1038/s41467-020-15066-6 OPEN Hyperoxia induces glutamine-fuelled anaplerosis in retinal Müller cells Charandeep Singh 1, Vincent Tran1, Leah McCollum1, Youstina Bolok1, Kristin Allan1,2, Alex Yuan1, ✉ George Hoppe1, Henri Brunengraber3 & Jonathan E. Sears 1,4 Although supplemental oxygen is required to promote survival of severely premature infants, hyperoxia is simultaneously harmful to premature developing tissues such as in the retina. 1234567890():,; Here we report the effect of hyperoxia on central carbon metabolism in primary mouse Müller glial cells and a human Müller glia cell line (M10-M1 cells). We found decreased flux from glycolysis entering the tricarboxylic acid cycle in Müller cells accompanied by increased glutamine consumption in response to hyperoxia. In hyperoxia, anaplerotic catabolism of glutamine by Müller cells increased ammonium release two-fold. Hyperoxia induces glutamine-fueled anaplerosis that reverses basal Müller cell metabolism from production to consumption of glutamine. 1 Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA. 2 Molecular Medicine, Case Western Reserve School of Medicine Cleveland, Cleveland, OH 44106, USA. 3 Department of Nutrition, Case Western Reserve School of Medicine Cleveland, Cleveland, OH 44106, USA. ✉ 4 Cardiovascular and Metabolic Sciences, Cleveland Clinic, Cleveland, OH 44195, USA. email: [email protected] NATURE COMMUNICATIONS | (2020) 11:1277 | https://doi.org/10.1038/s41467-020-15066-6 | www.nature.com/naturecommunications 1 ARTICLE NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-020-15066-6 remature infants require oxygen supplementation to sur- We first ensured that the isotopic steady state was established for Pvive, but excess oxygen causes retinovascular growth sup- at least 20 h before treating part of the cells with hyperoxia.
    [Show full text]
  • Moderate Intermittent Hypoxia/Hyperoxia: Implication for Correction of Mitochondrial Dysfunction
    Cent. Eur. J. Biol. • 7(5) • 2012 • 801-809 DOI: 10.2478/s11535-012-0072-x Central European Journal of Biology Moderate intermittent hypoxia/hyperoxia: implication for correction of mitochondrial dysfunction Research Article Olga A. Gonchar*, Irina N. Mankovska Department of Hypoxic States, Bogomoletz Institute of Physiology National Academy of Sciences of Ukraine, 01024 Kiev, Ukraine Received 26 January 2012; Accepted 06 June 2012 Abstract: The purpose of this study was to appreciate the acute hypoxia-induced mitochondrial oxidative damage development and the role of adaptation to hypoxia/hyperoxia (H/H) in correction of mitochondrial dysfunction. It was demonstrated that long-term sessions of moderate H/H [5 cycles of 5 min hypoxia (10% O2 in N2) alternated with 5 min hyperoxia (30% O2 in N2) daily for two weeks] attenuated 2+ basal and Fe /ascorbate-induced lipid peroxidation (LPO) as well as production of carbonyl proteins and H2O2 in liver mitochondria of rats exposed to acute severe hypoxia (7% O2 in N2, 60 min) in comparison with untreated animals. It was shown that H/H increases the activity of glutathione peroxidase (GPx), reduces hyperactivation of Mn-SOD, and decreases Cu,Zn- SOD activity as compared with untreated rats. It has been suggested that the induction of Mn-SOD protein expression and the coordinated action of Mn-SOD and GPx could be the mechanisms underlying protective effects of H/H, which promote the correction of the acute hypoxia- induced mitochondrial dysfunction. The increase in Mn-SOD protein synthesis without changes in Mn-SOD mRNA level under H/H pretreatment indicates that the Mn-SOD activity is most likely dependent on its posttranslational modification or on the redox state of liver mitochondria.
    [Show full text]
  • Physical Therapy Practice and Mechanical Ventilation: It's
    Physical Therapy Practice and Mechanical Ventilation: It’s AdVENTageous! Lauren Harper Palmisano, PT, DPT, CCS Rebecca Medina, PT, DPT, CCS Bob Gentile, RRT/NPS OBJECTIVES After this lecture you will be able to describe: 1. Indications for Mechanical Ventilation 2. Basic ventilator anatomy and purpose 3. Ventilator Modes, variables, and equations 4. Safe patient handling a. Alarms and what to expect b. Considerations for mobilization 5. Ventilator Liberation 6. LAB: Suctioning with Bob! INDICATIONS FOR MECHANICAL VENTILATION Cannot Ventilate Cannot Respirate Ventilation: the circulation of air Respiration: the movement of O2 from the outside environment to the cellular level, and the diffusion of Airway protection CO2 in the opposite direction ● Sedation ● Inflammation Respiratory Failure/Insufficiency ● Altered mental status ●Hypercarbic vs Hypoxic ●Vent will maintain homeostasis of CO2 and O2 ●Provides pressure support in the case of fatigued muscles of ventilation VENTILATOR ANATOMY ● Power supply/no battery ● O2 supply and Air supply ● Inspiratory/Expiratory Tubes ● Flow Sensor ● Ventilator Home Screen ● ET tube securing device- hollister ● Connection points - ET tube and trach HOME SCREEN What to observe: ● Mode ● Set rate ● RR ● FiO2 ● PEEP ● Volumes ● Peak and plateau pressures HOME SCREEN ● Mode ● Set rate ● RR ● FiO2 ● PEEP ● Volumes ● Peak and plateau pressures VENTILATION VARIABLES, EQUATIONS, & MODES Break it down ... VARIABLES IN DELIVERY Volume Flow (speed of volume delivery) in L/min Closed loop system ● No flow adjustment
    [Show full text]
  • Intracerebral Hemorrhage Related to Systemic Gas Embolism During Hysteroscopy
    UHM 2010, Vol. 37, No. 2 – Intracerebral hemorrhage in systemic gas embolism Intracerebral hemorrhage related to systemic gas embolism during hysteroscopy EMILIE GUILLARD, BÉNÉDICTE NANCY, HERVÉ FLOCH, ANNE HENCKES, GUY COCHARD, JOSIANE ARVIEUX, CHARLES CHRISTIAN ARVIEUX CHU Brest, Pôle Anesthesiology Intensive Care SAMU, Department of Anesthesiology and Intensive Care, Center for Hyperbaric Medicine, Brest, F-29200 France CORRESPONDING AUTHOR: Dr. Guy Cochard – [email protected] ABSTRACT Iatrogenic gas embolism is a rare but serious problem that has been documented in almost all medical specialties including gynecology. We present a 49-year-old woman undergoing operative hysteroscopy and myomectomy, who sustained sudden hypotension and decrease in the end-tidal carbon dioxid levels during the procedure. Systemic gas embolism was confirmed by echocardiographic evidence of bubbles in both right and left cardiac cavities and a rise of troponin. Hyperbaric oxygen was rapidly administered in addition to maintenance of vital functions and anti-thrombotic prevention with calciparin. A right hemiparesis was apparent after recovery from general anesthesia. Brain-computed tomography and magnetic resonnance imaging, performed on Days 3 and 2 respectively, showed a left fronto-parietal hematoma surrounded by edema. Having ruled out risk factors for a primary ischemic or hemorrhagic stroke, we concluded that hemorragic transformation of the ischemic cerebral lesion caused by gas embolism was responsible for the observed intraparenchymal hematoma. As far as we know, this is the first report relating cerebral gas embolism with an intracerebral hemorrhage. It provides an argument against anticoagulant therapy during the early stages of gas embolism care. INTRODUCTION transthoracic echocardiography. Cerebral imaging Air and gas embolism have been reported in almost studies demonstrated a single intraparenchymal all areas of clinical and surgical practice, including hematoma, consistent with the hemorrhagic operative hysteroscopy (1-3).
    [Show full text]
  • Misleading Hyperoxia Test
    Arch Dis Child: first published as 10.1136/adc.61.6.604 on 1 June 1986. Downloaded from 604 Archives of Disease in Childhood, 1986, 61 Misleading hyperoxia test A M C ENRIQUES, R McKAY, R M ARNOLD, AND J L WILKINSON The Royal Liverpool Children's Hospital, Liverpool carbon dioxide tension steadily increased. Chest SUMMARY A 2 day old infant with infracardiac total x ray films eventually showed bilateral diffuse anomalous pulmonary venous connection achieved opacities, and the hyperoxia test was repeated at 17 an arterial oxygen tension > 250 mmHg, breathing days. On this occasion, arterial oxygen tension 100% oxygen. Diagnosis of cardiac disease was increased only to 75 mmHg, and the patient was delayed several weeks. The anatomical basis for this referred for cardiac investigation. phenomenon was streaming of systemic venous On admission, the respiratory rate was 70 breaths return across an inferior vena cava type atrial septal per minute with intercostal recession and mild defect. central cyanosis. The second heart sound was single and accentuated, but no murmurs could be heard. Cardiorespiratory distress in the newborn infant may result from a variety of disorders. The hyper- oxia or nitrogen washout test is widely used and claimed to be a sensitive and accurate discriminator between cyanotic and acyanotic cardiac lesions and pulmonary disease. 1 An oxygen tension greater than 250 mmHg in an arterial sample from the right arm copyright. after 100% oxygen has been administered for 5-10 minutes is said to exclude cyanotic heart disease;2 while a value of more than 150 mmHg makes its occurrence extremely unlikely.3 In the patient presented here, however, a combination of factors obscured the typical presentation of a common mixing type, cyanotic heart lesion.
    [Show full text]
  • Oxygen Administration in Patients Recovering from Cardiac Arrest: a Narrative Review Ryo Yamamoto* and Jo Yoshizawa
    Yamamoto and Yoshizawa Journal of Intensive Care (2020) 8:60 https://doi.org/10.1186/s40560-020-00477-w REVIEW Open Access Oxygen administration in patients recovering from cardiac arrest: a narrative review Ryo Yamamoto* and Jo Yoshizawa Abstract High oxygen tension in blood and/or tissue affects clinical outcomes in several diseases. Thus, the optimal target PaO2 for patients recovering from cardiac arrest (CA) has been extensively examined. Many patients develop hypoxic brain injury after the return of spontaneous circulation (ROSC); this supports the need for oxygen administration in patients after CA. Insufficient oxygen delivery due to decreased blood flow to cerebral tissue during CA results in hypoxic brain injury. By contrast, hyperoxia may increase dissolved oxygen in the blood and, subsequently, generate reactive oxygen species that are harmful to neuronal cells. This secondary brain injury is particularly concerning. Although several clinical studies demonstrated that hyperoxia during post-CA care was associated with poor neurological outcomes, considerable debate is ongoing because of inconsistent results. Potential reasons for the conflicting results include differences in the definition of hyperoxia, the timing of exposure to hyperoxia, and PaO2 values used in analyses. Despite the conflicts, exposure to PaO2 > 300 mmHg through administration of unnecessary oxygen should be avoided because no obvious benefit has been demonstrated. The feasibility of titrating oxygen administration by targeting SpO2 at approximately 94% in patients recovering from CA has been demonstrated in pilot randomized controlled trials (RCTs). Such protocols should be further examined. Keywords: Cardiac arrest, Post cardia arrest syndrome, Oxygen, Hyperoxia, Hypoxic brain injury Background indicates that the initiation of oxygen treatment and the Many patients develop hypoxic brain injury after the re- amount of oxygen should be deliberately decided.
    [Show full text]
  • Lipid Peroxidation in Newborn Rabbits: Effects of Oxygen, Lipid Emulsion, and Vitamin El
    003 1-3998/86/2006-0505$02.00/0 PEDIATRIC RESEARCH Vol. 20, No. 6, 1986 Copyright O 1986 International Pediatric Research Foundation, Inc. Printed in U.S.A. Lipid Peroxidation in Newborn Rabbits: Effects of Oxygen, Lipid Emulsion, and Vitamin El JON R. WISPE,~MATTHEW KNIGHT,' AND ROBERT J. ROBERTS Division of Neonatology, Department of Pediatrics, University of lowa, College of Medicine, Iowa City, Iowa 52242 ABSTRACT. The extent of in vivo lipid peroxidation and with hyperoxic exposure, including bronchopulmonary dysplasia the in vivo antioxidant effects of a-tocopherol and a- and retrolental fibroplasia. tocopheryl acetate were studied in newborn rabbits exposed The exact mechanism by which oxidant tissue damage occurs to one of two oxidant stresses: hyperoxia (FIO~>0.9) or is not clear. Several lines of evidence support the hypothesis that parenteral lipid emulsion infusion. Lipid peroxidation was oxidant injury is mediated by the generation of partially reduced monitored by measurement of expired ethane and pentane, oxygen species (1-3). These reactive species may damage tissues tissue thiobarbituric acid (TBA) reactants, and tissue lipid by peroxidation of lipids, oxidation of proteins and nucleic acids, peroxides. Seventy-two h of hyperoxia did not increase any or through yet undefined mechanisms. It has long been presumed of the parameters of lipid peroxidation although mortality that polyunsaturated fatty acids in membranes are particularly was higher in oxygen exposed animals. a-Tocopherol (100 susceptible to oxidative processes, and that "lipid peroxidation" mg/kg, intravenous) lowered expired hydrocarbons and is a central feature of oxygen-associated tissue damage. Lipid tissue TBA reactants, but raised liver lipid peroxides in peroxidation is associated with the generation of lipid-derived both air and hyperoxia exposed pups.
    [Show full text]