The authors also thank Frank Schneider (Editing Coordinator, Division of Communication and Marketing of the Geneva University Hospitals, Geneva University Hospitals) and Justine Giliberto (Editing, Division of Communication and Marketing of the Geneva University Hospitals) for editing the video material. He is one of the founders of theFOAMmovement (Free Open-Access Medical education) and is co-creator oflitfl.com,theRAGE podcast, theResuscitologycourse, and theSMACCconference. , otolaryngology surgery).2,5,,7Many factors may increase the risk of laryngospasm.
Laryngospasm (Pediatric) | SpringerLink Second-level studies attempt to document the transfer of skills to the clinical setting and patient care. The next line of therapy would be to administer a low dose of succinylcholine (10Y20 mg) to relax the . font: 14px Helvetica, Arial, sans-serif; Target Audience: Training . ANESTHESIOLOGY 1981; 55:599602, Walker RW, Sutton RS: Which port in a storm? Broaddus VC, et al.
1. The exercise is then followed by a debriefing session during which constructive feedback is provided. TeamSTEPPS 2.0 Specialty Scenarios - 85 Specialty Scenarios OR Scenario 68 Appropriate for: All Specialties . Insufficient depth of anesthesia is one of the major causes of laryngospasm. These interventions include removal of the irritant stimulus,8,38chin lift, jaw thrust,39continuous positive airway pressure (CPAP), and positive pressure ventilation with a facemask and 100% O2.3,40,,43These maneuvers are popular because they have been shown to improve the patency of the upper airway in case of airway obstruction.42,4445Less commonly used airway maneuvers, such as pressure in the laryngospasm notch4,44and digital elevation of the tongue46also have been proposed as rapid and effective methods.8Overall conflicting results have been obtained regarding the best maneuver to relieve airway obstruction in children with laryngospasm. information highlighted below and resubmit the form. Anesth Analg 2002; 94:4949, Reber A, Bobbi SA, Hammer J, Frei FJ: Effect of airway opening manoeuvres on thoraco-abdominal asynchrony in anaesthetized children. Anesthesia was then maintained by facemask with 2.0% expired sevoflurane in a mixture of oxygen and nitrous oxide 50/50%. information submitted for this request. 21,22. .
Laryngospasm: Treatment, Definition, Symptoms & Causes - Cleveland Clinic Table 2. Anesthesiology 2012; 116:458471 doi: https://doi.org/10.1097/ALN.0b013e318242aae9. Get useful, helpful and relevant health + wellness information. PubMed PMID: 19669024. Alterations of upper airway reflexes may occur in several conditions. Portuguese. This content does not have an English version. clear: left; If IV access cannot be established in emergency, succinylcholine may be given by an alternative route.5354Intramuscular succinylcholine has been recommended at doses ranging from 1.5 to 4 mg/kg.53The main drawback of intramuscular administration is the slow onset in comparison with the IV route. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. This paper discusses a case study where the patient had laryngospasm, it also looks at the pathophysiology, risk factors and management of . padding-bottom: 0px; GERD: Can certain medications make it worse? Do Children Who Experience Laryngospasm Have an Increased Risk of Upper Respiratory Tract Infection? Laryngospasm. Only sevoflurane or halothane should be used for inhalational induction. In contrast, results from studies in children with recent URIs have shown that LMA was associated with an increased occurrence of laryngospasm.28,32In a recent, large, prospective study, the incidence of laryngospasm was increased after direct stimulation of the upper airway by both LMA and ETT in comparison with a facemask.5Therefore, LMA may be considered more stimulating than the facemask but certainly less than the ETT. have demonstrated an increased risk for laryngospasm only when cold symptoms were present on the day of surgery or less than 2 weeks before.28This finding was recently confirmed by the same team in an extensive study involving 9,297 surgical procedures.5Rescheduling patient 23 weeks after an URI episode appears to be a safe approach. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. Von Ungern-Sternberg et al. Some people may experience recurring (returning) laryngospasms. In case of sale of your personal information, you may opt out by using the link. In the study by von Ungern-Sternberg et al. According to Phil Larson: This notch is behind the lobule of the pinna of each ear. Inexperience of the anesthetist is also associated with an increased incidence of laryngospasm and perioperative respiratory adverse events.2,5,18Some factors are associated with a lower risk of laryngospasm: IV induction, airway management with facemask, and inhalational maintenance of anesthesia.5Induction and emergence from anesthesia are the most critical periods. Analytical cookies are used to understand how visitors interact with the website. Acta Anaesthesiol Scand 1999; 43:10813, Visvanathan T, Kluger MT, Webb RK, Westhorpe RN: Crisis management during anaesthesia: Laryngospasm. Can J Anaesth 2004; 51:45564, Goldmann K, Ferson DZ: Education and training in airway management. The patient is unconscious and initially breathing easily with an oral airway in place. Anaphylaxis (+/- Laryngospasm) A 7-year-old male presents with wheeze, rash and increased WOB after eating a birthday cake.
Epiglottitis - EMCrit Project A "can't ventilate, can't intubate" scenario may be prolonged when rocuronium is administered. The authors thank Frances O'Donovan, M.D., F.F.A.R.C.S.I. However, to our knowledge, no study has evaluated the effect of such a training approach on the management of laryngospasm. Laryngospasm is an emergency situation and must be promptly recognized. include protected health information. Paediatr Anaesth 2008; 18:297302, Cohen MM, Cameron CB: Should you cancel the operation when a child has an upper respiratory tract infection? It is frequently observed in fetuses and newborns, whereas later on, laryngeal closure reflex and cough become predominant.21This developmental pattern may be implicated in sudden infant death. This scenario illustrates the potential risks of not managing your resources properly. In reports addressing respiratory adverse events, including laryngospasm, the overall incidence of perioperative respiratory events as well as the incidence of laryngospasm was higher in 01-yr-old infants in comparison with older children.2,5,,7The risk of perioperative respiratory adverse event was quoted as decreasing by 8% for each increasing year of age.2A recent large cohort study confirmed this inverse relationship between age and risk of perioperative respiratory adverse events.5This study showed that the relative risk for perioperative respiratory adverse events, particularly laryngospasm, decreased by 11% for each yearly increase in age.5. Even though laryngospasm isnt usually serious or life-threatening, the experience can be terrifying. These cookies track visitors across websites and collect information to provide customized ads. demonstrated that in children age 26 yr, laryngeal and respiratory reflex responses differed between sevoflurane and propofol at similar depths of anesthesia, with apnea and laryngospasm being less severe with propofol.33If tracheal intubation is planned, the use of muscle relaxants prevents the risk of laryngospasm.2In contrast, topical anesthesia is probably not effective and the incidence of laryngospasm is even higher when vocal cords are sprayed with aerosolized lidocaine.5, Laryngospasm is commonly caused by systemic painful stimulation if the anesthesia is too light during maintenance. ANESTHESIOLOGY 1996; 85:47580, Nishino T: Physiological and pathophysiological implications of upper airway reflexes in humans. Call for help early. Because these symptoms can be frightening, it is good to have a clear medical plan for prevention and treatment if you have any of these symptoms. The patient will then develop worsened hypotension, requiring the start of an epinephrine infusion. Paediatr Anaesth 2008; 18:2818, Hampson-Evans D, Morgan P, Farrar M: Pediatric laryngospasm. privacy practices. A new episode of laryngospasm was immediately suspected. In the recent analysis of 189 reports of laryngospasm to the Australian Incident Monitoring Study, one in three patients suffered significant physiological disturbance.
PDF pan 2446 303. - McGill University Qual Saf Health Care 2005; 14:e3, Fernandez E, Williams DG: Training and the European Working Time Directive: A 7 year review of paediatric anaesthetic trainee caseload data. In addition, a video of a simulated layngospasm scenario is available (See video, Supplemental Digital Content 1, http://links.lww.com/ALN/A807, which demonstrates the management of a simulated laryngospasm in a 10-month-old boy). It is not the same as choking. Check out these best-sellers and special offers on books and newsletters from Mayo Clinic Press. Laryngospasm is a frightening condition that happens when your vocal cords suddenly seize up, making breathing more difficult. can occur spontaneously, most commonly associated with extubation or ENT procedures CAUSES Local extubation especially children with URTI symptoms It is mandatory to procure user consent prior to running these cookies on your website. This means that if nothing has occurred 46 h after the occurrence of a laryngospasm it is likely that the course will be uneventful. Curr Opin Anaesthesiol 2009; 22:38895, Owen H: Postextubation laryngospasm abolished by doxapram. Any use of this site constitutes your agreement to the Terms and Conditions and Privacy Policy linked below. Learn more about the symptoms here. But opting out of some of these cookies may have an effect on your browsing experience.
Bronchospasm: Symptoms, Causes, Diagnosis, Treatment - Verywell Health Anesth Analg 1996; 82:7247, Skolnick ET, Vomvolakis MA, Buck KA, Mannino SF, Sun LS: Exposure to environmental tobacco smoke and the risk of adverse respiratory events in children receiving general anesthesia. Finally, third-level studies evaluate the effect of education on patient outcomes. More needed than oxygen! Based on a work athttps://litfl.com. Understanding the mechanics of laryngospasm is crucial for proper treatment. border: none; Although described in the conscious state and associated with silent reflux, laryngospasm is a problematic reflex which occurs often under general anaesthesia. Thereafter, surgery was quickly completed, while tracheal extubation and postoperative recovery were uneventful. PubMed PMID: Salem MR, Crystal GJ, Nimmagadda U. Breathe in and out through the straw without pausing between the inhale and the exhale.
Laryngospasm mechanism - OpenAnesthesia Advertising on our site helps support our mission. Laryngospasms can be frightening, whether youve experienced them before or not. Review. Anesth Analg 1991; 72:2828, Garca CG, Bhore R, Soriano-Fallas A, Trost M, Chason R, Ramilo O, Mejias A: Risk factors in children hospitalized with RSV bronchiolitis, Tait AR, Malviya S, Voepel-Lewis T, Munro HM, Seiwert M, Pandit UA: Risk factors for perioperative adverse respiratory events in children with upper respiratory tract infections. Cleveland Clinic is a non-profit academic medical center. , the overall incidence of respiratory adverse events seems to be higher in children who were awake when their LMA was removed and lower in those who were awake when their endotracheal tube was removed.5In summary, evidence seems to favor deep LMA and awake ETT removal. Nasal foreign body, ketamine and laryngospasm, Clinical Adjunct Associate Professor at Monash University, Australia and New Zealand Clinician Educator Network, Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. If the cause is unclear, your doctor may refer you to an ear, nose and throat specialist (otolaryngologist) to look at your vocal cords with a mirror or small fiberscope to be sure there is no other abnormality. The goal is to slow your breathing and allow your vocal cords to relax. Can J Anaesth 2010; 57:74550, Sanikop C, Bhat S: Efficacy of intravenous lidocaine in prevention of post extubation laryngospasm in children undergoing cleft palate surgeries. If positive-pressure ventilation is to be performed, then moderate intermittent pressure should be applied. Although the efficacy of subhypnotic doses of propofol has been suggested in children, there is a possibility that these doses are inadequate in infants, especially in those younger than 1 yr. Am J Med 2001; 111(Suppl 8A):69S77S, Shannon R, Baekey DM, Morris KF, Lindsey BG: Brainstem respiratory networks and cough. It persists for a longer period in the context of respiratory syncytial virus infection, hypoxia, and anemia.21, The diagnosis of laryngospasm depends on the clinical judgment of the anesthesiologist. Laryngospasm is usually defined as partial or complete airway obstruction associated with increasing abdominal and chest wall efforts to breathe against a closed glottis.3,5,7In both partial and complete laryngospasm, signs of varying degrees of airway obstruction, such as suprasternal retraction, supraclavicular retractions, tracheal tug, paradoxical chest, and abdominal movements may be seen.3In addition, inspiratory stridor may be heard in partial laryngospasm but is absent in complete spasm. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. #mergeRow-gdpr fieldset label { Upper respiratory tract infection (URI) is associated with a twofold to fivefold increase in the risk of laryngospasm.5,9Anesthesiologists in charge of pediatric patients should be aware that the risks associated with a URI in an infant are magnified in this age group, especially in those with respiratory syncytial virus infection.10Children with URI are prone to develop airway (upper and bronchial) hyperactivity that lasts beyond the period of viral infection. We do not endorse non-Cleveland Clinic products or services. Management There are a number of ways reported to reduce the incidence of laryngospasm (9). Anaesthesia 2002; 57:1036, Chung DC, Rowbottom SJ: A very small dose of suxamethonium relieves laryngospasm. If we combine this information with your protected Evidence on this subject is scarce, but the study by von Ungern-Sternberg et al. Risk Factors Associated with Perioperative Laryngospasm, Young age is one of the most important risk factors. Laryngospasm in amyotrophic lateral sclerosis.
laryngospasm - EM Sim Cases APPENDIX. Laryngospasm may not be obvious it may present as increased work of breathing (e.g. Laryngospasms are rare and typically last for fewer than 60 seconds. Laryngospasm can sometimes occur after an endotracheal tube is removed from the throat. Larson CP Jr. Laryngospasmthe best treatment. Laryngospasm remains the leading cause of perioperative cardiac arrest from respiratory origin in children.1, The upper airway has several functions (swallowing, breathing, and phonation) but protection of the airway from any foreign material is the most essential. Sci Transl Med 2010; 2:19cm8. Here are some important features to keep in mind: Complete blockage may present as just apnea; Can be preceded by high-pitched inspiratory stridor, followed by complete airway obstruction OVERVIEW Laryngospasm is potentially life-threatening closure of the true vocal chords resulting in partial or complete airway obstruction unresponsive to airway positioning maneuvers. Anesth Analg 1991; 73:26670, Rachel Homer J, Elwood T, Peterson D, Rampersad S: Risk factors for adverse events in children with colds emerging from anesthesia: A logistic regression. He had been fasting for the past 6 h. Preoperative evaluation was normal (systemic blood pressure 85/50 mmHg, heart rate 115 beats/min, pulse oximetry [SpO2] 99% on room air). Anaesthesia 2007; 62:7579, Tobias JD, Nichols DG: Intraosseous succinylcholine for orotracheal intubation. Paediatr Anaesth 2005; 15:10947, Nawfal M, Baraka A: Propofol for relief of extubation laryngospasm. J Anesth 2010; 24:8547, Schroeck H, Fecho K, Abode K, Bailey A: Vocal cord function and bispectral index in pediatric bronchoscopy patients emerging from propofol anesthesia. They can help figure out whats causing them. Anaesthesia 1983; 38:3935, Sibai AN, Yamout I: Nitroglycerin relieves laryngospasm. Recently, a new technique with gentle chest compression has been proposed as an alternative to standard practice for relief of laryngospasm.47In this before-after study, extubation laryngospasm was managed with standard practice (CPAP and gentle positive pressure ventilation via a tight-fitting facemask with 100% O2via facemask) during the first 2 yr of the study, whereas in the following 2 yr, laryngospasm was managed with 100% O2and concurrent gentle chest compression. ANESTHESIOLOGY 2010; 113:2007, Roy WL, Lerman J: Laryngospasm in paediatric anaesthesia. 2. other information we have about you. Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. It is bounded anteriorly by the ascending ramus of the mandible adjacent to the condyle, posteriorly by the mastoid process of the temporal bone, and cephalad by the base of the skull.. The purpose of this case scenario is to highlight key points essential for the prevention, diagnosis, and treatment of laryngospasm occurring during anesthesia. He is also a Clinical Adjunct Associate Professor at Monash University. stroke, hypoxic encephalopathy), Attempt to break the laryngospasm by applying painful inward and anterior pressure at , If hypoxia supervenes consider administering, Laryngospasm is usually brief and may be followed by a. Management of refractory laryngospasm. Vocal cord dysfunction. Fig.
Designing a Simulation Scenario - StatPearls - NCBI Bookshelf You might experience multiple laryngospasms in a brief time but in most cases, each episode ends after about a minute. | INTENSIVE | RAGE | Resuscitology | SMACC. Hold your breath for five seconds, then repeat until the laryngospasm stops. Use of suxamethonium without intravenous access for severe laryngospasm. have demonstrated an increased risk for laryngospasm only when cold symptoms are present the day of surgery or less than 2 weeks before (table 2).5Therefore, for children who present for elective procedures with a temperature higher than 38C, mucopurulent airway secretions, or lower respiratory tract signs such as wheezing and moist cough, surgery is usually postponed.
Laryngospasm LITFL Medical Blog CCC Ventilation 1. If laryngospasms are due to anxiety, then anti-anxiety meds can help ease your spasms. Even though you may feel like you cant breathe, try to remember that the episode will pass. A computer-aided incidence study in 136,929 patients Acta Anaesthesiol Scand 1984; 28:56775, Burgoyne LL, Anghelescu DL: Intervention steps for treating laryngospasm in pediatric patients. SimBaby is a tetherless simulator designed to help healthcare providers effectively recognize and respond to critically ill pediatric patients. Furthermore, the efficacy of propofol to break complete laryngospasm when bradycardia is present has been questioned.4In our case, two bolus doses of 5 mg IV propofol (each representing a dose of 0.6 mg/kg) were administered but did not relieve airway obstruction. Most of the time, your healthcare provider can diagnose laryngospasm by reviewing your symptoms and medical history. All rights reserved. A competence-based training that includes a structured curriculum and regular workplace-based assessment may help mitigate the effects of caseload reduction. Laryngospasms are rare. PEEP! Paediatr Anaesth 2004; 14:15866, Olsson GL, Hallen B: Laryngospasm during anaesthesia. Paediatr Anaesth 2004; 14:21824, Alalami AA, Ayoub CM, Baraka AS: Laryngospasm: Review of different prevention and treatment modalities. [. Laryngospasm can happen suddenly and without warning, lasting up to one minute. Collins S, Schedler P, Veasey B, Kristofy A, McDowell M. In children with URI, the use of an endotracheal tube (ETT) may increase by 11-fold the risk of respiratory adverse events, in comparison with a facemask.11Less invasive airway management could be beneficial in children with airway hyperactivity. So, treatment often involves finding ways to stay calm during the episode. More specifically, laryngeal closure reflex involves the laryngeal intrinsic muscles responsible for vocal folds adduction, i.e. Principal effectors are respiratory muscles (diaphragm, intercostals, abdominals, and upper airway). Causes: hypocalcemia, painful stimuli . Necessary cookies are absolutely essential for the website to function properly.
[PDF] Case scenario: perianesthetic management of laryngospasm in 2012 Feb;116(2):458-71. doi: 10.1097/ALN.0b013e318242aae9. The team must initiate usual anaphylaxis treatment including salbutamol for bronchospasm. , at the condyles of the ascending rami of the mandible, then its efficacy would be improved. Paediatr Anaesth 2003; 13:437, Schreiner MS, O'Hara I, Markakis DA, Politis GD: Do children who experience laryngospasm have an increased risk of upper respiratory tract infection? Difficulty breathing ( dyspnea) Fatigue and exhaustion are other less-common and more subtle symptoms that may be associated with bronchospasm. , partial or complete) and of the bradycardia as well as the existence of contraindication to succinylcholine. 3, 5, 7 In both partial and complete laryngospasm, signs of varying degrees of airway obstruction, such as suprasternal retraction, supraclavicular retractions, tracheal tug, Definition. Anaesthesia 1998; 53:91720, Ko C, Kocaman F, Aygen E, Ozdem C, Ceki A: The use of preoperative lidocaine to prevent stridor and laryngospasm after tonsillectomy and adenoidectomy.
Evaluation and Management of Psychiatric Emergencies in the - JEMS Elsevier; 2022. https://www.clinicalkey.com. Such a conservative attitude has already been proposed for otolaryngology patients, whose surgery is expected to have an effect on the recurrence of URI episodes.11Premedication with anticholinergic agents may decrease secretions but has no demonstrated influence on the incidence of laryngospasm.7,29. } If youve experienced a laryngospasm, schedule an appointment with your healthcare provider. Br J Anaesth 2001; 86:21722, Mark LC: Treatment of laryngospasm by digital elevation of tongue (letter). These results are in accordance with a study showing that subhypnotic doses of propofol (0.5 mg/kg) decreased the likelihood of laryngospasm upon tracheal extubation in children undergoing tonsillectomy with or without adenoidectomy.50Lower doses of propofol (0.25 mg/kg) have also been used successfully to relax the larynx in a small series.51It should be noted that few data are available regarding the use of propofol to treat laryngospasm in younger age groups (younger than 3 yr). Anesthesiology. People with laryngospasm are unable to speak or breathe. Journal of Voice. We also use third-party cookies that help us analyze and understand how you use this website. Paediatr Anaesth 2008; 18:28996, Oberer C, von Ungern-Sternberg BS, Frei FJ, Erb TO: Respiratory reflex responses of the larynx differ between sevoflurane and propofol in pediatric patients. Shortness of breath. If you or someone youre with is having a laryngospasm, you should: In addition to the techniques outlined above, there are breathing exercises that can help you through a laryngospasm. More children who developed laryngospasm were successfully treated with chest compression (73.9%) compared with those managed with the standard method (38.4%; P< 0.001). Singapore Med J 1998; 39:32830, Warner DO: Intramuscular succinylcholine and laryngospasm. To confirm the diagnosis, your healthcare provider may look at your vocal cords with a laryngeal endoscope. Refer to each drug's package Therefore, the injection of IV succinylcholine was required to treat this persistent laryngospasm. Minimally invasive anti-reflux procedures, Advertising and sponsorship opportunities. Muscles involved: lateral cricoarytenoid, thyroarytenoids (both from recurrent laryngeal), crycrothyroid (from external branch of superior laryngeal). Laryngospasm, particularly during inhalational induction and after extubation, is an important cause of apnea that all anesthesiologists who care for pediatric patients should understand and anticipate. Recognizing laryngospasm - laryngospasm can occur spontaneously and be life-threatening, making it important that you be able to recognize it immediately. Stimulation of upper airway mucosa also produces cardiovascular (alterations of the arterial pressure, bradycardia, etc.) Without quick recognition and proper treatment, the patient's airway may occlude, leading to respiratory arrest followed by cardiac arrest. The first step of laryngospasm management is prevention. Laryngospasm is usually defined as partial or complete airway obstruction associated with increasing abdominal and chest wall efforts to breathe against a closed glottis. These risk factors can be Adults may be less prone to development of laryngospasm. https://www.aaaai.org/conditions-treatments/related-conditions/vocal-cord-dysfunction. Laryngospasm is identied by varying degrees of airway obstruction with paradoxical chest move-ment, intercostal recession and tracheal tug. To avoid significant morbidity and mortality, the use of a structured algorithm has been proposed.8,70One study suggests that if correctly applied, a combined core algorithm recommended for the diagnosis and management of laryngospasm would have led to earlier recognition and/or better management in 16% of the cases.70These results should encourage physicians to implement their own structured algorithm for the diagnosis and management of laryngospasm in children in their institutions. Pulm Pharmacol Ther 2004; 17:37781, Suskind DL, Thompson DM, Gulati M, Huddleston P, Liu DC, Baroody FM: Improved infant swallowing after gastroesophageal reflux disease treatment: A function of improved laryngeal sensation? Thus, the potential window for safe administration of general anesthesia is frequently very short. In children, an artificial cough maneuver, including a single lung inflation maneuver with 100% O2immediately before removal of the ETT, is useful at the time of extubation because it delays or prevents desaturation in the first 5 min after extubation in comparison with a suctioning procedure.36Although not demonstrated in this study, this technique could reduce laryngospasm because when the endotracheal tube leaves the trachea, the air escapes in a forceful expiration that removes residual secretions from the larynx. Laryngospasms that are caused by other conditions like asthma, stress or hypersensitivity arent usually dangerous or life-threatening.
Laryngospasm scenario. More needed than oxygen! PEEP! #mc_embed_signup { When it happens, the vocal cords suddenly seize up or close when taking in a breath, blocking the flow of air into the lungs.People with this . If complete laryngospasm cannot be rapidly relieved, IV agents should be quickly considered. Otolaryngol Head Neck Surg 1998; 118:8802, Gulhas N, Durmus M, Demirbilek S, Togal T, Ozturk E, Ersoy MO: The use of magnesium to prevent laryngospasm after tonsillectomy and adenoidectomy: A preliminary study. 2). Airway management training, including management of laryngospasm, is an area that can significantly benefit from the use of simulators and simulation.73These tools represent alternative nonclinical training modalities and offer many advantages: individuals and teams can acquire and hone their technical and nontechnical skills without exposing patients to unnecessary risks; training and teaching can be standardized, scheduled, and repeated at regular intervals; and trainees' performances can be evaluated by an instructor who can provide constructive feedback, a critical component of learning through simulation.7475. Fig. Laryngoscope 2006; 116:1397403, Nishino T, Hasegawa R, Ide T, Isono S: Hypercapnia enhances the development of coughing during continuous infusion of water into the pharynx.