DOCSLIB.ORG

Vocal Cord Dysfunction JAMES DECKERT, MD, Saint Louis University School of Medicine, St

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Vocal Cord Dysfunction JAMES DECKERT, MD, Saint Louis University School of Medicine, St Vocal Cord Dysfunction JAMES DECKERT, MD, Saint Louis University School of Medicine, St. Louis, Missouri LINDA DECKERT, MA, CCC-SLP, Special School District of St. Louis County, Town & Country, Missouri Vocal cord dysfunction involves inappropriate vocal cord motion that produces partial airway obstruction. Patients may present with respiratory distress that is often mistakenly diagnosed as asthma. Exercise, psychological conditions, airborne irritants, rhinosinusitis, gastroesophageal reflux disease, or use of certain medications may trigger vocal cord dysfunction. The differential diagnosis includes asthma, angioedema, vocal cord tumors, and vocal cord paralysis. Pulmo- nary function testing with a flow-volume loop and flexible laryngoscopy are valuable diagnostic tests for confirming vocal cord dysfunction. Treatment of acute episodes includes reassurance, breathing instruction, and use of a helium and oxygen mixture (heliox). Long-term manage- ment strategies include treatment for symptom triggers and speech therapy. (Am Fam Physician. 2010;81(2):156-159, 160. Copyright © 2010 American Academy of Family Physicians.) ▲ Patient information: ocal cord dysfunction is a syn- been previously diagnosed with asthma.8 A handout on vocal cord drome in which inappropriate Most patients with vocal cord dysfunction dysfunction, written by the authors of this article, is vocal cord motion produces par- have intermittent and relatively mild symp- provided on page 160. tial airway obstruction, leading toms, although some patients may have pro- toV subjective respiratory distress. When a per- longed and severe symptoms. son breathes normally, the vocal cords move Laryngospasm, a subtype of vocal cord away from the midline during inspiration and dysfunction, is a brief involuntary spasm of only slightly toward the midline during expi- the vocal cords that often produces aphonia ration.1 However, in patients with vocal cord and acute respiratory distress. Laryngospasm dysfunction, the vocal cords move toward is a common complication of anesthesia.11 the midline during inspiration or expiration, Another variation of vocal cord dysfunc- which creates varying degrees of obstruction.2 tion is spasmodic dysphonia, which causes Vocal cord dysfunction has numerous labels hoarseness and strained vocalization when in the literature, including paradoxical vocal the abnormal vocal cord motion occurs dur- cord dysfunction,3 paradoxical vocal fold ing speech.12 motion,4 and factitious asthma.5 Differential Diagnoses Clinical Presentation The primary diagnosis to consider in patients Vocal cord dysfunction occurs more often in with respiratory distress or wheezing is women than in men, and is common in per- asthma. Vocal cord dysfunction is often mis- sons 20 to 40 years of age.2,6,7 However, stud- diagnosed as asthma, and a considerable sub- ies have identified vocal cord dysfunction in set of patients with vocal cord dysfunction adolescents and in children as young as eight also have asthma, making the diagnosis more years.8 difficult.2,8 A careful patient history may help Patients with vocal cord dysfunction typi- to differentiate between the two conditions. cally present with recurrent episodes of sub- Unlike asthma, vocal cord dysfunction causes jective respiratory distress that are associated more difficulty with inspiration than expira- with inspiratory stridor, cough, choking sen- tion, and is commonly associated with a sen- sations, and throat tightness.3 The presence sation of throat tightness or choking. However, of wheezing can indicate an asthma exacer- further testing, including pulmonary function bation, but is commonly a mistaken descrip- testing and laryngoscopy, is usually required tion of the stridor characteristic of vocal to make the diagnosis.13 Additional conditions cord dysfunction.9,10 In one study, 59 percent in the differential diagnosis of vocal cord dys- of patients with vocal cord dysfunction had function are listed in Table 1. 156 American Family Physician www.aafp.org/afp Volume 81, Number 2 ◆ January 15, 2010 Downloaded from the American Family Physician Web site at www.aafp.org/afp. Copyright © 2010 American Academy of Family Physicians. For the private, noncommercial use of one individual user of the Web site. All other rights reserved. Contact [email protected] for copyright questions and/or permission requests. Vocal Cord Dysfunction SORT: KEY RECOMMENDATIONS FOR PRACTICE Evidence Clinical recommendation rating References Exercise-induced vocal cord dysfunction should be strongly considered in patients diagnosed C 7, 8 with exercise-induced asthma who respond poorly to usual treatment. Pulmonary function testing with a flow-volume loop is useful in confirming a diagnosis of vocal C 2, 22-25 cord dysfunction. Reassurance and breathing instruction may resolve an acute episode of vocal cord dysfunction. C 27 Pretreatment with inhaled ipratropium (Atrovent) may be a helpful adjunct in patients with C 8 exercise-induced vocal cord dysfunction. A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease- oriented evidence, usual practice, expert opinion, or case series. For information about the SORT evidence rating system, go to http://www.aafp. org/afpsort.xml. ammonia, dust, smoke, soldering fumes, Table 1. Differential Diagnosis of Vocal Cord Dysfunction and cleaning chemicals. Studies have shown a clear temporal relationship between expo- Anaphylaxis Laryngotracheobronchitis (croup) sure and onset of symptoms.17 Angioedema Presence of foreign body RHINOSINUSITIS Asthma Tracheal stenosis Epiglottitis Vocal cord paralysis Postnasal drip associated with rhinosinusitis Hypoparathyroidism Vocal cord tumors or polyps has been linked to airway hyperresponsive- Laryngomalacia (in adults) ness.18 A high prevalence of rhinosinusitis in patients with vocal cord dysfunction and case reports of resolution of vocal cord dysfunc- Precipitating Factors tion symptoms with treatment suggest that rhinosinusitis Vocal cord dysfunction is associated with a variety of may play a role in some patients.17 precipitating factors, but no clear unifying pathophysi- ology has been identified. GASTROESOPHOGEAL REFLUX DISEASE Gastroesophageal reflux disease (GERD) has been impli- EXERCISE cated in triggering vocal cord dysfunction.19 In some Exercise is a common cause of vocal cord dysfunction. studies, a high prevalence of GERD was identified in Exercise-induced vocal cord dysfunction is often mis- patients with vocal cord dysfunction20; however, treat- diagnosed as exercise-induced asthma.8 It should be ment of GERD was only effective in decreasing vocal strongly considered in patients with dyspnea on exertion cord dysfunction in some patients. who have been diagnosed with exercise-induced asthma, particularly if they respond poorly to usual treatment Medication use with bronchodilators.7 Neuroleptic drugs, specifically phenothiazines, may cause transient vocal cord dysfunction. This appears to PSYCHOLOGICAL CONDITIONS be a focal dystonic reaction and is associated with extra- Studies have reported associations between vocal cord pyramidal signs, such as torticollis.21 dysfunction and multiple psychological conditions, including posttraumatic stress disorder, anxiety, depres- Diagnostic Approaches sion, and panic attack.14 Anxiety disorders appear to be The most valuable diagnostic tests for vocal cord dys- particularly common in adolescent patients with vocal function are pulmonary function testing with a flow- cord dysfunction.15 However, associated depression and volume loop and flexible laryngoscopy. Other testing, anxiety may also be consequences of persistent respira- such as measurement of arterial blood gases, may be use- tory symptoms, rather than causes.16 ful in ruling out other possible diagnoses. IRRITANTS PULMONARY FUNCTION TESTING Exposure to environmental and occupational irritants Pulmonary function testing with a flow-volume loop is has been found to precipitate respiratory symptoms con- the most commonly used diagnostic test to confirm vocal sistent with vocal cord dysfunction. Common airborne cord dysfunction. In the flow-volume loop, it is typical irritants associated with vocal cord dysfunction include for the expiratory loop to be normal and the inspiratory January 15, 2010 ◆ Volume 81, Number 2 www.aafp.org/afp American Family Physician 157 Vocal Cord Dysfunction 14 14 13 13 12 12 11 11 10 10 9 9 loop to be flattened, which is consistent with 8 8 an extrathoracic upper airway obstruction 7 7 6 6 (Figure 1). This pattern is characteristic of 5 5 patients when they are symptomatic.22 Even 4 4 when asymptomatic, some patients with 3 3 second) 2 2 vocal cord dysfunction will demonstrate 1 1 per 2 0 0 inspiratory loop flattening. Exercise flow- 43210 5 543210 -1 -1 volume loops, performed in conjunction -2 -2 (liters with exercise testing, may be useful in iden- -3 -3 -4 -4 tifying patients with exercise-induced vocal Flow -5 -5 cord dysfunction.23 -6 -6 -7 -7 Pulmonary function testing is particu- -8 -8 larly useful in differentiating vocal cord -9 -9 -10 -10 dysfunction from asthma because bron- -11 -11 chospasm produces an impaired expiratory -12 -12 -13 -13 loop that is different from that seen in vocal -14 -14 24 cord dysfunction. In cases with an unclear Volume (liters) etiology, or if concurrent asthma and vocal cord dysfunction are suspected, methacho- Figure 1. Flow-volume loop. (Left) Normal expiratory and inspiratory line challenge
Load more

Recommended publications
  • Vocal Cord Dysfunction in Amyotrophic Lateral Sclerosis Four Cases and a Review of the Literature
    NEUROLOGICAL REVIEW SECTION EDITOR: DAVID E. PLEASURE, MD Vocal Cord Dysfunction in Amyotrophic Lateral Sclerosis Four Cases and a Review of the Literature Maaike M. van der Graaff, MD; Wilko Grolman, MD, PhD; Erik J. Westermann, MD; Hans C. Boogaardt; Hans Koelman, MD, PhD; Anneke J. van der Kooi, MD, PhD; Marina A. Tijssen, MD, PhD; Marianne de Visser, MD, PhD e describe 4 patients with amyotrophic lateral sclerosis (ALS) and glottic nar- rowing due to vocal cord dysfunction, and review the literature found using the following search terms: amyotrophic lateral sclerosis, motor neuron disease, stri- dor, laryngospasm, vocal cord abductor paresis, and hoarseness. Neurological Wliterature rarely reports vocal cord dysfunction in ALS, in contrast to otolaryngology literature (4%- 30% of patients with ALS). Both infranuclear and supranuclear mechanisms may play a role. Vocal cord dysfunction can occur at any stage of disease and may account for sudden death in ALS. Treat- ment of severe cases includes acute airway management and tracheotomy. Arch Neurol. 2009;66(11):1329-1333 Amyotrophic lateral sclerosis (ALS) is a neu- (VCAP), it is potentially life threatening, as rodegenerative disease characterized by fea- a predominance of vocal cord adduction re- tures indicative of both upper and lower sults in glottic narrowing or even occlu- motor neuron degeneration. Initial manifes- sion. Assessment by an otolaryngologist is tations usually include weakness in the bul- then of the highest priority. Stridor is a well- bar region or weakness of the limbs. Progres- known symptom in multiple system atro- sive weakness leads to increasing disability phy and may also incidentally occur in other and respiratory insufficiency, resulting in neurodegenerative diseases.8-10 Laryngo- death.
    [Show full text]
  • Full Text (PDF)
    REVIEW COPD Physiological and clinical relevance of exercise ventilatory efficiency in COPD J. Alberto Neder1, Danilo C. Berton1,2, Flavio F. Arbex3, Maria Clara Alencar4, Alcides Rocha3, Priscila A. Sperandio3, Paolo Palange5 and Denis E. O’Donnell1 Affiliations: 1Respiratory Investigation Unit and Laboratory of Clinical Exercise Physiology, Queen’s University and Kingston General Hospital, Kingston, ON, Canada. 2Division of Respiratory Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil. 3Pulmonary Function and Clinical Exercise Physiology, Respiratory Division, Federal University of Sao Paulo, Sao Paulo, Brazil. 4Division of Cardiology, Federal University of Minas Gerais, Belo Horizonte, Brazil. 5Dept of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy. Correspondence: J. Alberto Neder, 102 Stuart Street, Kingston, Ontario, Canada K7L 2V6. E-mail: [email protected] @ERSpublications Ventilatory efficiency is a key measurement for the interpretation of cardiopulmonary exercise testing in COPD http://ow.ly/1nsY307pbz8 Cite this article as: Neder JA, Berton DC, Arbex FF, et al. Physiological and clinical relevance of exercise ventilatory efficiency in COPD. Eur Respir J 2017; 49: 1602036 [https://doi.org/10.1183/13993003.02036- 2016]. ABSTRACT Exercise ventilation (V′E) relative to carbon dioxide output (V′CO2) is particularly relevant to patients limited by the respiratory system, e.g. those with chronic obstructive pulmonary disease (COPD). ′ − ′ High V E V CO2 (poor ventilatory efficiency) has been found to be a key physiological abnormality in symptomatic patients with largely preserved forced expiratory volume in 1 s (FEV1). Establishing an ′ − ′ association between high V E V CO2 and exertional dyspnoea in mild COPD provides evidence that exercise intolerance is not a mere consequence of detraining.
    [Show full text]
  • The Use of Heliox in Treating Decompression Illness
    The Diving Medical Advisory Committee DMAC, Eighth Floor, 52 Grosvenor Gardens, London SW1W 0AU, UK www.dmac-diving.org Tel: +44 (0) 20 7824 5520 [email protected] The Use of Heliox in Treating Decompression Illness DMAC 23 Rev. 1 – June 2014 Supersedes DMAC 23, which is now withdrawn There are many ways of treating decompression illness (DCI) at increased pressure. In the past 20 years, much has been published on the use of oxygen and helium/oxygen mixtures at different depths. There is, however, a paucity of carefully designed scientific studies. Most information is available from mathematical models, animal experiments and case reports. During a therapeutic compression, the use of a different inert gas from that breathed during the dive may facilitate bubble resolution. Gas diffusivity and solubility in blood and tissue is expected to play a complex role in bubble growth and shrinkage. Mathematical models, supported by some animal studies, suggest that breathing a heliox gas mixture during recompression could be beneficial for nitrogen elimination after air dives. In humans, diving to 50 msw, with air or nitrox, almost all cases of DCI can be adequately treated at 2.8 bar (18 msw), where 100% oxygen is both safe and effective. Serious neurological and vestibular DCI with only partial improvements during initial compression at 18 msw on oxygen may benefit from further recompression to 30 msw with heliox 50:50 (Comex therapeutic table 30 – CX30). There have been cases successfully treated on 50:50 heliox (CX30), on the US Navy recompression tables with 80:20 and 60:40 heliox (USN treatment table 6A) instead of air and in heliox saturation.
    [Show full text]
  • Vocal Cord Dysfunction: a Review Neha M
    Dunn et al. Asthma Research and Practice (2015) 1:9 DOI 10.1186/s40733-015-0009-z REVIEW Open Access Vocal cord dysfunction: a review Neha M. Dunn1*, Rohit K. Katial2 and Flavia C. L. Hoyte2 Abstract Vocal cord dysfunction (VCD) is a term that refers to inappropriate adduction of the vocal cords during inhalation and sometimes exhalation. It is a functional disorder that serves as an important mimicker of asthma. Vocal cord dysfunction can be difficult to treat as the condition is often underappreciated and misdiagnosed in clinical practice. Recognition of vocal cord dysfunction in patients with asthma-type symptoms is essential since missing this diagnosis can be a barrier to adequately treating patients with uncontrolled respiratory symptoms. Although symptoms often mimic asthma, the two conditions have certain distinct clinical features and demonstrate specific findings on diagnostic studies, which can serve to differentiate the two conditions. Moreover, management of vocal cord dysfunction should be directed at minimizing known triggers and initiating speech therapy, thereby minimizing use of unnecessary asthma medications. This review article describes key clinical features, important physical exam findings and commonly reported triggers in patients with vocal cord dysfunction. Additionally, this article discusses useful diagnostic studies to identify patients with vocal cord dysfunction and current management options for such patients. Keywords: Vocal cord dysfunction, Paradoxical vocal fold movement, Vocal cord, Asthma-comorbidity Introduction medical literature 70 years later, in 1974, by Patterson Vocal cord dysfunction (VCD) is a term that refers to in- and colleagues in a 33 year old woman with 15 hospitali- appropriate adduction of the vocal cords during inhalation zations for what they termed “Munchausen’s stridor” [6].
    [Show full text]
  • Vocal Cord Dysfunction (VCD)
    Leaders In Allergy & Asthma Care For Over 40 Years Vocal Cord Dysfunction (VCD) Vocal cord dysfunction (VCD) is a disorder of the vocal cords (or vocal folds). When a patient experiences VCD, the vocal cords adduct (come together) during inspiration when they should abduct (spread apart). Smooth movement of air into and out of the chest is obstructed and it is harder to breathe. During VCD episodes patients feel anxious, helpless, or terrified. Patients typically feel as if they can’t breathe. Some patients feel faint. The exact cause of VCD remains unknown. Symptoms that commonly occur during VCD include: Wheezing (a whistling sound typically from the neck) Shortness of breath Hoarseness Audible breathing (stridor) Throat or chest tightness Triggers of VCD include: Exercise Coughing Acid reflux (GERD) Breathing cold air Breathing irritants (tobacco smoke, pollution, strong odors etc.) Stress (emotional and psychosocial issues) VCD verses Asthma VCD may mimic or coexist with asthma. Symptoms and triggers of VCD can overlap with those of asthma. Correct diagnosis is important since asthma medication will have little or no effect on symptoms caused by VCD and may even make symptoms worse. Patients who have VCD along with asthma will frequently find that their usual asthma therapy is no longer as effective at preventing breathing difficulties or that asthma "rescue medication" no longer works. Diagnosis Correct diagnosis is important. The diagnosis of VCD is made based on history, physical examination, and testing. Testing to evaluate asthma is important. Your doctor may recommend special testing to determine if you have asthma, VCD, or both.
    [Show full text]
  • Diagnostic Direct Laryngoscopy, Bronchoscopy & Esophagoscopy
    Post-Operative Instruction Sheet Diagnostic Direct Laryngoscopy, Bronchoscopy & Esophagoscopy Direct Laryngoscopy: Examination of the voice box or larynx (pronounced “lair-inks”) under general anesthesia. An instrument called a laryngoscope is carefully placed into the mouth and used to visualize the larynx and surrounding structures. Bronchoscopy: Examination of the windpipe below the voice box in the neck and chest under general anesthesia. A long narrow telescope is passed through the larynx and used to carefully inspect the structures of the trachea and bronchi. Esophagoscopy: Examination of the swallowing pipe in the neck and chest under general anesthesia. An instrument called an esophagoscope is passed into the esophagus (just behind the larynx and trachea) and used to visualize the mucus membranes and surrounding structures of the esophagus. Frequently a small biopsy is taken to evaluate for signs of esophageal inflammation (esophagitis). What to Expect: Diagnostic airway endoscopy procedures generally take about 45 minutes to complete. Usually the procedure is well-tolerated and the child is back-to-normal the next day. Mild throat or tongue discomfort may persist for a few days after the procedure and is usually well-controlled with over-the-counter acetaminophen (Tylenol) or ibuprofen (Motrin). Warning Signs: Contact the office immediately at (603) 650-4399 if any of the following develop: • Worsening harsh, high-pitched noisy-breathing (stridor) • Labored breathing with chest retractions or flaring of the nostrils • Bluish discoloration of the lips or fingernails (cyanosis) • Persistent fever above 102°F that does not respond to Tylenol or Motrin • Excessive coughing or respiratory distress during feeding • Coughing or throwing up bright red blood • Excessive drowsiness or unresponsiveness Diet: Resume baseline diet (no special postoperative diet restrictions).
    [Show full text]
  • Editorial Vocal Cord Dysfunction and Wheezing
    Thorax 1991;46:401-404 401 THORAX Thorax: first published as 10.1136/thx.46.6.401 on 1 June 1991. Downloaded from Editorial Vocal cord dysfunction and wheezing Most respiratory physicians have experience of treating A case report entitled "Au igen's..tridor" in 1974 patients whose symptoms of wheezing seem out ofpropor- illustrated several points that are common to the spectrum tion to the pathophysiology (if any) of their asthma. These of vocal cord dysfunction.' The patient, a 33 year old patients are difficult to treat and often continue to have woman, was admitted to hospital on 15 occasions with severe symptoms. They frequently have side effects from inspiratory wheeze precipitatea by infection or emotional their treatment, in particular iny n- uZset. Clinical examination showed nothing abnormal drome. Although this is acknowledged widely within the apart from Achypnoea and high pitched stridor. The specialty it is not well documented in published papers. attacks resolved atter emergency treatment. The results of Wheezing occurs in a wide range oforganic lung diseases subseq:unt inveuLigaLioIs, including taryngoscopy and as a result of reversible and irreversible airflow limitation, bronchoscopy, were normal. Once the nature of the illness localised endobronchial disease (tumour or sarcoidosis), was recognised the patient was referred for psychiatric care and diffuse lung disease (pulmonary oedema or lym- and no further attacks were reported. phangitis). The differential diagnosis ofacute wheezing also Subsequent reports of "non-organic acute upper airway includes a separate disease entity that we choose to call obstruction"8 and "functional upper airway obstruction"' "vocal cord dysfunction." This condition has a psy- provided more detailed physiological data.
    [Show full text]
  • Efficacy of Fiberoptic Laryngoscopy in the Diagnosis of Inhalation Injuries
    ORIGINAL ARTICLE Efficacy of Fiberoptic Laryngoscopy in the Diagnosis of Inhalation Injuries Thomas Muehlberger, MD; Dario Kunar, MD; Andrew Munster, MD; Marion Couch, MD, PhD Background: Asignificantproportionofburnpatientswith Results: Six (55%) of 11 patients had clinical findings and inhalation injuries incur difficulties with airway protection, symptoms that indicated, under traditional criteria, endo- dysphagia, and aspiration. In assessing the need for intu- tracheal intubation for airway protection. Visualization of bation in burn patients, the efficacy of fiberoptic laryngos- the upper airway with fiberoptic laryngoscopy obviated the copy was compared with clinical findings and the findings need for endotracheal intubation in all 11 patients. These of diagnostic tests, such as arterial blood gas analysis, mea- patients also failed to evidence an increased risk of aspira- surement of carboxyhemoglobin levels, pulmonary func- tion or other swallowing dysfunction. tion tests, and radiography of the lateral aspect of the neck. Conclusions: In comparison with other diagnostic cri- Objective: To determine if these patients were at risk teria, fiberoptic laryngoscopy allows differentiation of for aspiration or dysphagia, barium-enhanced fluoro- those patients with inhalation injuries who, while at scopic swallowing studies were performed. risk for upper airway obstruction, do not require intu- bation. These patients may be safely observed in a moni- Design: Prospective study. tored setting with serial fiberoptic examinations, thus avoiding the possible complications associated with in- Settings: Burn intensive care unit in an academic ter- tubation of an airway with a compromised mucosalized tiary referral center. surface. In these patients, swallowing abnormalities do not manifest. Main Outcome Measures: Need for endotracheal in- tubation and potential for aspiration.
    [Show full text]
  • Respiratory Therapy Pocket Reference
    Pulmonary Physiology Volume Control Pressure Control Pressure Support Respiratory Therapy “AC” Assist Control; AC-VC, ~CMV (controlled mandatory Measure of static lung compliance. If in AC-VC, perform a.k.a. a.k.a. AC-PC; Assist Control Pressure Control; ~CMV-PC a.k.a PS (~BiPAP). Spontaneous: Pressure-present inspiratory pause (when there is no flow, there is no effect ventilation = all modes with RR and fixed Ti) PPlateau of Resistance; Pplat@Palv); or set Pause Time ~0.5s; RR, Pinsp, PEEP, FiO2, Flow Trigger, rise time, I:E (set Pocket Reference RR, Vt, PEEP, FiO2, Flow Trigger, Flow pattern, I:E (either Settings Pinsp, PEEP, FiO2, Flow Trigger, Rise time Target: < 30, Optimal: ~ 25 Settings directly or by inspiratory time Ti) Settings directly or via peak flow, Ti settings) Decreasing Ramp (potentially more physiologic) PIP: Total inspiratory work by vent; Reflects resistance & - Decreasing Ramp (potentially more physiologic) Card design by Respiratory care providers from: Square wave/constant vs Decreasing Ramp (potentially Flow Determined by: 1) PS level, 2) R, Rise Time (­ rise time ® PPeak inspiratory compliance; Normal ~20 cmH20 (@8cc/kg and adult ETT); - Peak Flow determined by 1) Pinsp level, 2) R, 3)Ti (shorter Flow more physiologic) ¯ peak flow and 3.) pt effort Resp failure 30-40 (low VT use); Concern if >40. Flow = more flow), 4) pressure rise time (¯ Rise Time ® ­ Peak v 0.9 Flow), 5) pt effort (­ effort ® ­ peak flow) Pplat-PEEP: tidal stress (lung injury & mortality risk). Target Determined by set RR, Vt, & Flow Pattern (i.e. for any set I:E Determined by patient effort & flow termination (“Esens” – PDriving peak flow, Square (¯ Ti) & Ramp (­ Ti); Normal Ti: 1-1.5s; see below “Breath Termination”) < 15 cmH2O.
    [Show full text]
  • Respiratory Problems – Occupational and Environmental Exposures
    The respiratory tract Respiratory problems Occupational and environmental exposures Ryan F Hoy Background Case study The respiratory tract comes into contact with approximately A man, 23 years of age and previously well, presents with 14 000 litres of air during a standard working week. The 2 months of cough, shortness of breath and weight loss. quality of the air we breathe has major implications for our He reports intermittent fevers and flu-like symptoms over respiratory health. Any part of the respiratory tract, from the the same period. During a recent 2 week holiday to Bali nose to the alveoli, may be adversely affected by exposure to he felt significantly better, but after returning home he airborne contaminants. has had a recurrence of symptoms. Objective Occupational and exposure history identifies him as This article outlines some common occupational and commencing work at a mushroom farm 12 months environmental exposures that can lead to respiratory problems. ago where he is exposed to dust from the mixing of mushroom compost. He is not required to use respiratory Discussion protection at work. His cough and chest tightness Some of the effects of exposures may be immediate, whereas usually start in the afternoon at work and persist into others such as asbestos-related lung disease may not present the evening. Other workers at the mushroom farm have for many decades. Airborne contaminants may be the primary reported similar symptoms and have had to leave the cause of respiratory disease or can exacerbate pre-existing workplace as a result. respiratory conditions such as asthma and chronic obstructive pulmonary disease.
    [Show full text]
  • Training Objectives for a Diving Medical Physician
    The Diving Medical Advisory Committee Training Objectives for a Diving Medicine Physician This guidance includes all the training objectives agreed by the Diving Medical Advisory Committee, the European Diving Technology Committee and the European Committee for Hyperbaric Medicine in 2011. Rev 1 - 2013 INTRODUCTION The purpose of this document is to define more closely the training objectives in diving physiology and medicine that need to be met by doctors already fully accredited or board-certified in a clinical speciality to national standards. It is based on topic headings that were originally prepared for a working group of European Diving Technology Committee (EDTC) and the European Committee of Hyperbaric Medicine (ECHM) as a guide for diving medicine some 20 years ago by J.Desola (Spain), T.Nome (Norway) & D.H.Elliott (U.K.). The training now required for medical examiners of working divers and for specialist diving medicine physicians was based on a EDTC/ECHM standard 1999 and subsequently has been enhanced by the Diving Medical Advisory Committee (DMAC), revised and agreed in principle by DMAC, EDTC and ECHM in 2010 and then ratified by EDTC and ECHM in 2011. The requirements now relate to an assessment of competence, the need for some training in occupational medicine, the need for maintenance of those skills by individual ‘refresher training’. Formal recognition of all this includes the need to involve a national authority for medical education. These objectives have been applied internationally to doctors who provide medical support to working divers. (Most recreational instructors and dive guides are, by their employment, working divers and so the guidance includes the relevant aspects of recreational diving.
    [Show full text]
  • A Review of the Use of Heliox in the Critically Ill
    Special review A Review of the use of Heliox in the Critically Ill T. WIGMORE, E. STACHOWSKI Intensive Care Unit, Westmead Hospital, Westmead, NEW SOUTH WALES ABSTRACT Heliox, a mix of oxygen and helium, has a number of potential medical applications resulting from its relatively lower density. This paper reviews the physics underlying its utility and considers the evidence for its use. While there are studies that support its role, particularly in patients with exacerbations of asthma and chronic obstructive pulmonary disease (COPD), the data are inconclusive. (Critical Care and Resuscitation 2006; 8: 64-72) Key words: Heliox, helium, airway obstruction, asthma, chronic obstructive pulmonary disease Helium was discovered in 1868 by the French astro- a given pressure difference. Clinically this can be utilis- nomer Pierre-Jules-Cesar Janssen during a spectro- ed to assist patients who suffer from airway narrowing. scopic study of a total solar eclipse in India. It was named later the same year by the British astronomer Table 1. Physical properties of pure gases at RTP Joseph Norman Lockyer and chemist Sir Edward (298 degrees Kelvin and 1 atmosphere pressure) Frankland, the name derived from helios, the Greek for Density Viscosity Thermal sun. It is an inert gas present in the atmosphere (ρ) (η) conductivity (0.00052%) and was used initially in airships and Kg/m3 microPoise W/m K balloons. Today, most commercial helium is recovered from Air 1.184 184.33 0.025 natural gas using a cryogenic separation process, foll- owing which it is refined and liquefied. Liquid helium is Carbon 1.811 148.71 0.017 shipped from the production site to various storage Dioxide facilities worldwide before being distributed in the Helium 0.166 197.61 0.14 gaseous form into cylinders for on-site use.
    [Show full text]