The unanticipated difficult airway with recommendations for management

Consent and anaesthetic risk

The incidences of mortality and morbidity associated with anaesthesia were reviewed. Most of the published incidences for common complications of anaesthesia vary considerably. Where possible, a realistic estimate of the incidence of each morbidity has been made, based on the best available data. Perception of risk and communication of anaesthetic risk to patients are discussed. The incidences of anaesthetic complications are compared with the relative risks of everyday events, using a community cluster logarithmic scale, in order to place the risks in perspective when compared with other complications and with the inherent risks of surgery. Documentation of these risks and discussion with patients should allow them to be better informed of the relative risks of anaesthetic complications. Depending on specific comorbidities and the severity of operation, these risks associated with anaesthesia may increase for any one individual.

The gum elastic bougie eases tracheal intubation while applying cricoid pressure compared to a stylet

PURPOSE

To compare the ease of tracheal intubation facilitated by the gum elastic bougie or the malleable stylet while applying cricoid pressure.

METHODS

Sixty American Society of Anesthesiologists I-III adult patients undergoing elective surgeries participated in this study. After induction of anesthesia with 2.5 mg x kg(-1) propofol and vecuronium 0.1 mg x kg(-1), the laryngeal view was assessed without and with cricoid pressure. Patients were allocated randomly into two groups: a gum elastic bougie or stylet group. One of the two devices was used for tracheal intubation while applying cricoid pressure. The duration and ease of tracheal intubation was recorded.

MAIN RESULTS

In 58 patients, the trachea was intubated at the first attempt. In the stylet group, tracheal intubation was difficult and needed more time, especially when the glottic opening was not visible. In the bougie group, the duration and ease of intubation was not influenced by laryngeal view. In the remaining two patients with Cook's modified 3b laryngeal view, it was impossible to intubate the trachea with these devices.

CONCLUSIONS

Applying cricoid pressure worsened laryngeal view. The use of a gum elastic bougie was more effective than the use of a stylet to facilitate intubation.

Structure and process quality illustrated by fibreoptic intubation: analysis of 1612 cases

The purpose of this investigation was the description of structure and process quality based on the analysis of 1612 fibreoptic intubations. We evaluated all fibreoptic intubations (nasotracheal in awake patients and orotracheal in anaesthetised patients) from a previously described database over a period of 2 years. We assessed structure quality by evaluating the distribution of the fibreoptic intubations across all staff anaesthetists, and process quality by analysing the number of attempts, the time required, the cases where we had to switch to conventional intubation and the complications. In all, 955 nasotracheal and 657 orotracheal intubations were evaluated. Almost all anaesthetists performed at least 15 nasotracheal and 10 orotracheal intubations. The success rate was 85.2% at the first attempt. Within 3 min, 93.9% of all fibreoptic intubations were successfully completed. In 24 cases, fibreoptic intubation was abandoned. Severe nasal bleeding as a major complication occurred in 1.3% of the nasotracheal intubations.

Prevalence of a training module for difficult airway management: a comparison between Japan and the United Kingdom

To examine the education of trainees with regard to difficult airway management, we sent a questionnaire to all 89 Japanese University Departments of Anaesthesia (to be answered by a person who was responsible for teaching trainees) and all 280 Royal College of Anaesthetists' Tutors in the UK. The presence or absence of a formal training module for difficult airway management, timing and methods of training, types of airway devices that should be taught, and tutors' expertise with various techniques and devices were surveyed. Sixty-seven of the 89 Japanese tutors (75%) and 167 of 280 UK tutors (60%) replied to the questionnaire. Only 19 of 67 (28%) Japanese anaesthetists and 33 of 167 (20%) UK anaesthetists who replied, indicated that they had a difficult airway training module. In six Japanese departments (9%) and 115 (69%) UK departments, equipment for percutaneous transtracheal ventilation was readily available. Airway devices and techniques that tutors considered necessary to be mastered in the first 2 years of training, differed considerably between Japan and the UK, with notable differences in the use of gum elastic bougies and awake intubation. A training module for difficult airway management is often not provided and equipment for emergency transtracheal ventilation is often unavailable in both countries.

Use of a new videolaryngoscope (GlideScope) in the management of a difficult airway

PURPOSE

To describe the clinical use of a new videolaryngoscope in a patient who had repeatedly been difficult or impossible to intubate by conventional direct laryngoscopy. This device provided excellent glottic visualization and permitted easy endotracheal intubation.

CLINICAL FEATURES

A 74-yr-old male presenting for repeat elective surgery had a history of failed intubations by direct laryngoscopy and pulmonary aspiration with a laryngeal mask airway. He refused awake flexible fibreoptic intubation. After the induction of general anesthesia, laryngoscopy was performed using a GlideScope. This provided complete glottic exposure and easy endotracheal intubation.

CONCLUSION

This new videolaryngoscope provided excellent laryngeal exposure in a patient whom multiple experienced anesthesiologists had repeatedly found to be difficult or impossible to intubate using direct laryngoscopy. The clinical role of this device awaits confirmation in a large series of difficult airways.

Management of the difficult airway: alternative airway techniques and adjuncts

Rapid-sequence intubation using conventional laryngoscopic technique remains the standard of airway management in emergency medicine and continues to have a success rate of approximately 98%. Preparation and proper intubation technique must be optimized at the initial attempt using direct laryngoscopy. Failure causes multiple repeated attempts, leading to a failed airway. Each repeated attempt increases the likelihood of bleeding, oral, pharyngeal, and laryngeal edema, and malposition, causing decreased visualization of the glottic opening, equipment failure, and hypoxia. Preparation must be an ongoing process. Faulty suction, no oxygen source, choice of the wrong laryngoscopic blade or ETT, poor light source, or misplaced equipment can domino into mechanical failure. Intubation equipment stations must be inventoried constantly, organized, and kept simple in their layout to decrease confusion during selection. Medication for sedation and paralysis should be readily available and not kept distant from the intubation station in a medication-dispensing unit that would require time for acquisition. Proper positioning of the patient remains paramount for alignment of the oral, pharyngeal, and laryngeal axis to provide optimal visualization of the vocal cords. Proper technique during insertion of the laryngoscope blade in the oral cavity for displacement of the tongue must be ensured. Without proper technique, even with proper positioning, the glottic opening cannot be visualized. Laryngeal pressure to maneuver the larynx into position should be exerted initially by the laryngoscopist's right hand and, when in view, maintained by an assistant to free the laryngoscopist's hand for ETT insertion. With preparation and proper technique, the first attempt is the best attempt, and the vicious cycle of multiple attempts and complications will be averted.

Obstetric emergencies

Obstetric hemorrhage is still a significant cause of maternal morbidity and mortality. Prevention, early recognition, and prompt intervention are the keys to minimizing complications. Resuscitation can be inadequate because of under-estimation of blood loss and misleading maternal response. A young woman may maintain a normal blood pressure until sudden and catastrophic decompensation occurs. All members of the obstetric team should know how to manage hemorrhage because timing is of the essence. Good communication with the blood bank ensures timely release of appropriate blood products. A well-coordinated team is one of the most important elements in the care of a compromised fetus. If fetal anoxia is presumed, there is less than 10 minutes to permanent fetal brain damage. Antepartum anesthesia consultation should be encouraged in parturients with medical problems.

'Airway Alerts'. How UK anaesthetists organise, document and communicate difficult airway management

A questionnaire on organisation, documentation and communication of airway problems during anaesthesia was sent to 271 anaesthetic college tutors in the UK. Their responses were compared with three published recommendations. There was a 72% response rate (195/271). The recommendations of the American Society of Anaesthesiologists Task Force on the Management of the Difficult Airway were met by 71% of respondents; 2% met those suggested by the Canadian Airway Focus Group and 2% met those suggested in a standard UK textbook on difficulties in tracheal intubation. Guidelines for management of the difficult airway were available in 142 departments (73%), but only 41 (21%) had guidelines for communication and dissemination of information. We present an 'Airway Alert' scheme which has since been adopted by the Difficult Airway Society.

The Esophageal-Tracheal Combitube

The ETC is an easily inserted, double-lumen/double-balloon supraglottic airway device. The major indication of the ETC is as a back-up device for airway management. It is an excellent option for rescue ventilation in both in- and out-of-the-hospital environments and in situations of difficult ventilation and intubation. It is useful especially in patients with massive airway bleeding or limited access to the airway and in patients in whom neck movement is contraindicated. Continued airway management with an ETC that has been placed is a reasonable option in many cases. Having thus secured the airway, it may not be necessary to abort the anesthetic or to continue with further airway management efforts. In order to avoid serious trauma to the esophagus or airway, redesigning the ETC using a softer material for the tube is advisable.

Management choices for the difficult airway by anesthesiologists in Canada

PURPOSE

This study assessed difficult airway management, training and equipment availability among Canadian anesthesiologists.

METHODS

A postal survey of active members of the Canadian Anesthesiologists' Society was conducted in 2000. Respondents chose an induction condition and intubation technique for each of ten difficult airway scenarios. Availability of airway devices in their workplaces was assessed. Chi square analyses were used to compare groups. A P value of < 0.05 was considered statistically significant.

RESULTS

Eight hundred and thirty-three of 1702 (49%) surveys were returned. Staff comprised 88%, and residents 12%. Fifty-five percent had attended a difficult airway workshop within five years and 30% received mannequin airway training during residency. Direct laryngoscopy (48%) or fibreoptic bronchoscopy (34%) were the preferred techniques for intubation. For laryngeal, subglottic and unstable cervical spine scenarios, awake intubation with fibreoptic bronchoscope was most widely chosen. Asleep intubation with direct laryngoscopy was most commonly selected for trauma scenarios. Availability of difficult airway equipment varied between regions and types of hospital. Cricothyroidotomy equipment and difficult airway carts were not universally available.

CONCLUSIONS

Our survey assessed current preferences, training and equipment availability for the difficult airway amongst Canadian anesthesiologists. Direct laryngoscopy and fibreoptic bronchoscopy were the preferred technique for intubation despite widespread availability of newer airway equipment. Lack of certain essential airway equipment and difficult airway training should be addressed.

The LMA-ProSeal is an effective alternative to tracheal intubation for laparoscopic cholecystectomy

PURPOSE

To compare LMA-ProSeal (LMA-PS) with endotracheal tube (ETT) with respect to pulmonary ventilation and gastric distension during laparoscopic cholecystectomy.

METHODS

We randomized 109 ASA I-III adults to LMA-PS or ETT after stratifying them as non-obese or obese (body mass index > 30 kg x m-2). After preoxygenation, anesthesia was induced with propofol, fentanyl and rocuronium. An LMA-PS (women #4, men #5) or ETT (women 7 mm, men 8 mm) was inserted and the cuff inflated. A #14 gastric tube was passed into the stomach in every patient and connected to continuous suction. Anesthesia was maintained with nitrous oxide, oxygen and isoflurane. Ventilation was set at 10 mL x kg-1 and 10 breaths x min-1. The surgeon, blinded to the airway device, scored stomach size on an ordinal scale of 0-10 at insertion of the laparoscope and upon decompression of the pneumoperitoneum.

RESULTS

There were no statistically significant differences in SpO2 or P(ET)CO2 between the two groups before or during peritoneal insufflation in either non-obese or obese patients. Median (range) airway pressure at which oropharyngeal leak occurred during a leak test with LMA-PS was 34 (18-45) cm water. Change in gastric distension during surgery was similar in both groups. Four of 16 obese LMA-PS patients crossed over to ETT because of respiratory obstruction or airway leak.

CONCLUSIONS

A correctly seated LMA-PS or ETT provided equally effective pulmonary ventilation without clinically significant gastric distension in all non-obese patients. Further studies are required to determine the acceptability of the LMA-PS for laparoscopic cholecystectomy in obese patients.

An unexpected difficult laryngoscopy

A case of unexpected difficult laryngoscopy in a patient with gross hydrocephalus and generalized hypertonus is described. The 30-month-old girl had no antecedent history of such difficulty, having had two recent uneventful anaesthetics. We suggest that the reason for our inability to open the patient's mouth was a result of contracture of the temporalis muscle. The patient was managed using a laryngeal mask airway with controlled ventilation.

The Shikani Seeing Stylet for difficult intubation in children: initial experience

The Shikani Seeing Stylet is a recently introduced reusable intubating stylet, produced in adult and paediatric versions. It combines features of a fibreoptic bronchoscope and a lightwand. Inside a malleable stainless steel sheath, the Shikani Seeing Stylet has a fibreoptic cable leading to a distal light source and high-resolution lens. In use, the stylet is placed in the lumen of the selected endotracheal tube and the light source enables the stylet to be used as a lightwand, while the fibreoptic capability enables visualization of the laryngeal inlet. It is portable, relatively inexpensive and easy to maintain. This report describes the use of the stylet on eight occasions in seven children, all of whom were assessed preoperatively as being potentially difficult to intubate. Three had been difficult to intubate previously. All were anaesthetized using inhalational anaesthesia. Once an adequate depth of anaesthesia had been achieved, conventional direct laryngoscopy was performed and identified as Grade 3 in six of the patients and Grade 1 in one. Tracheal intubation was then attempted using the Shikani Seeing Stylet. On six of the eight occasions the attempt was made by different anaesthetists, none of whom had any prior clinical experience with the stylet. There were seven successful intubations and one failure in a patient who could not be intubated by any method. The Shikani Seeing Stylet seems a useful device for use in children with difficult airway problems, suspected cervical spine instability or limited mouth-opening.

[Serious intraoperative problems--a five-year review of 83,844 anesthetics]

PURPOSE

The low incidence of mortality and major morbidity in anesthesia makes it difficult to study the pattern of potential accidents and to develop preventive strategies. Anesthetic 'near-misses', however, occur more frequently. Using data from a simple routine-based system of problem reporting, we have analyzed the pattern and causes of serious non-fatal problems, in order to improve preventive strategies.

METHODS

We prospectively recorded anesthesia-related information from all anesthetics for five years. The data included intraoperative problems, which were graded into four levels, according to severity. We analyzed only the serious nonfatal problems, which were sorted according to clinical presentation, and also according to which factor was most important in the development of the problem. We assessed any untoward consequences for the patient, and whether the problems could have been prevented.

RESULTS

Serious problems were recorded in 315 cases out of 83,844 (0.4%). Anesthesia was considered the major contributing factor in 111 cases. Difficult intubation, difficult emergence from general anesthesia, allergic reactions, arrhythmia and hypotension were the dominating problems. Twenty-six anesthesia related problems resulted in changes in level of postoperative care, and one patient later died in the intensive care unit after anaphylactic shock. Eighty-two problems could have been prevented by simple strategies.

CONCLUSION

Analysis of serious nonfatal problems during anesthesia may contribute to improved preventive strategies. Data from a routine-based system are suitable for this type of analysis. Intubation, emergence, arrhythmia, hypotension and anaphylaxis cause most serious problems, and should be the object of preventive strategies.

Airway management in the emergency department

Airway management in the emergency department and the role of anaesthetists and emergency physicians is reviewed. The training for emergency physicians in the advanced airway skills of rapid sequence induction and tracheal intubation is discussed.

Prehospital tracheal intubating conditions during rapid sequence intubation: rocuronium versus vecuronium

INTRODUCTION

The study purpose was to evaluate tracheal intubating conditions and cardiovascular effects of rocuronium (roc) and vecuronium (vec) in the transport setting.

METHODS

A prospective blinded study of adult patients requiring emergency rapid sequence oral tracheal intubation using direct laryngoscopy. Patients received equipotent doses of roc 1.0 mg/kg (n = 44) or vec 0.15 mg/kg (n = 56) on an alternate day basis.

RESULTS

Intubation was successful in 95% of patients in the vec group and 100% in the roc group. The percentage of patients having good or excellent jaw relaxation and vocal cord exposure was similar between groups (vec/79%, roc/77%). Eleven patients (vec/7, roc/4) had difficult intubation as evidenced by Grade III or IV view and more than three attempts. Five patients in the vec group had inadequate neuromuscular blockade versus 1 patient in the roc group (P = 0.17). No cardiovascular differences occurred between groups after intubation.

CONCLUSION

Tracheal intubating conditions and clinical evidence of complete neuromuscular blockade tended to be better after roc than after vec.

A new technique for difficult intubations

A Macintosh laryngoscope was modified to allow a rigid fibreoptic scope to be attached. Our purpose was to determine if Cormack and Lehane scores could be improved using the described fibreoptic technique, thus allowing easier intubating conditions. In order to assess its value for intubation, a study was performed on 53 patients. Thirty-three of these patients were classified to be difficult intubations (suspected or unanticipated). The Cormack and Lehane scores were improved by the use of the modified laryngoscope by one to three grades compared to the standard laryngoscopy. Significantly improved intubating condition were observed. The assessment demonstrates that many patients with Mallampati scores of III and IV can be successfully managed by this technique.

Rapid sequence induction: a national survey of practice

We performed a national postal survey exploring anaesthetists' practice in rapid sequence induction. All respondents used pre-oxygenation, although the technique employed, and its reliability, varied. Thiopental and succinylcholine, given after waiting for signs of loss of consciousness, were the most widely used drugs for rapid sequence induction. Propofol and rocuronium were used by more than a third of respondents, and most respondents (75%) also routinely administered an opioid. Cricoid pressure was used universally but the practice of its application varied widely. The commonest aids used if intubation was difficult were the gum elastic bougie, the long laryngoscope blade and the laryngeal mask. After failed intubation, approximately half of respondents would maintain the supine position. Failure to intubate at rapid sequence intubation had been seen by 45% of respondents but harm was uncommon. In contrast, 28% had seen regurgitation, which frequently led to considerable harm and to three deaths. In spite of this, practice of a failed intubation drill was uncommon (15%) and anaesthetic assistants were rarely known to practice application of cricoid pressure. Consultants were less likely than trainees to use rocuronium as a muscle relaxant, and more likely to choose morphine if administering an opioid. They were less likely to practice a failed intubation drill. Other aspects of practice varied little between grades. This survey suggests that many anaesthetists do not follow best practice when performing a rapid sequence induction.

Asymptomatic lingual tonsillar hypertrophy and difficult airway management: a report of three cases

PURPOSE

To report on the airway management of three cases of asymptomatic lingual tonsillar hypertrophy (LTH).

MATERIAL

On three separate occasions, patients presenting for elective surgery were subsequently found to have asymptomatic LTH. In all cases preoperative airway examination was essentially unremarkable and no unusual difficulties were anticipated. In the first case, despite an inability to visualize the glottic opening, the patient was intubated successfully on the initial attempt and had no further problems in the perioperative period. In the second case, neither direct laryngoscopy, utilizing the MacIntosh and McCoy blades, nor fibreoptic visualization enabled successful intubation. Ventilation was maintained with a laryngeal mask airway (LMA) until the anesthetic was reversible. Upon awakening and removal of the LMA, the patient totally obstructed and could not be ventilated, necessitating emergency cricothyroidotomy. The third patient was an elderly gentleman in whom successful intubation was eventually achieved, with considerable difficulty, by the otorhinolaryngologist (ENT surgeon) utilizing a straight blade. On a second occasion, he was again intubated by the same ENT surgeon, this time utilizing the anterior commissure blade. All three patients were subsequently discharged without further sequelae.

CONCLUSION

Asymptomatic LTH can cause varying degrees of unexpected difficulty in securing the airway and, at present, no single method will necessarily improve the chances of successful intubation. Therefore, strategies to manage unanticipated difficult intubation secondary to supraglottic airway pathology need to be performed and practiced, including the establishment of a transtracheal airway.

Airway management behaviour, experience and knowledge among Danish anaesthesiologists--room for improvement

BACKGROUND

Problems with managing the airways in relation to anaesthesia causes severe morbidity and mortality. A large proportion of these adverse respiratory events is preventable. Still patients continue to die from airway disasters related to anaesthesia, also in Scandinavia. The goal of this study is to identify which efforts are likely to improve this situation.

METHODS

A questionnaire asking about experience, behaviour and availability of various items of equipment was mailed to all members of the Danish Society of Anaesthesiologists and were returned anonymously.

RESULTS

More than 65% of respondents have sufficient access to a flexible fibrescope, but still 17% of specialists have no access and the vast majority (>67%) has little (1-10 times) or no experience in its use for awake intubation. A total of 52-70% knew the basic principles of the ASA difficult airway algorithm, but despite this only 25-50% would perform awake intubation if a difficult intubation was expected. More than 20% of respondents had experienced preventable airway management mishaps. In all, 18-46% did not know how to oxygenate via the cricothyroid membrane.

CONCLUSION

There is room for improvement regarding airway management skills among Danish anaesthesiologists. It is likely that airway management can be improved by: A) Better knowledge of an appropriate plan, algorithm, for airway management. B) Awake intubation used more often. C) More experience in fibreoptic intubation. D) All anaesthesiologists accepting that previous difficult intubation is an indicator of future difficulties. E) All anaesthesiologists knowing, and practising on manikins, how to oxygenate via the cricothyroid membrane. F) Always having a laryngeal mask airway immediately available when inducing anaesthesia.

Fiberoptically-guided insertion of transtracheal catheters

IMPLICATIONS

Regular use of the transtracheal catheter (TTC) both offers an opportunity for training for the difficult airway and facilitates elective endoscopic surgery. Fiberoptic guidance and exploratory puncture improve the insertion of the TTC.

Asymptomatic vallecular cyst: airway management considerations

Airway problems are easiest to manage when they are anticipated. Difficult intubation might, however, occur in patients with no obvious signs or symptoms suggesting airway difficulty. We describe a case where laryngeal inlet was obscured by a large vallecular cyst that was discovered during rapid-sequence induction of general anesthesia, causing difficulty in tracheal intubation. Once the patient was allowed to recover from general anesthesia, the trachea could be safely intubated using a fiberoptic bronchoscope.

Video-intuboscopic assistance is a useful aid to tracheal intubation in pediatric patients

PURPOSE

To evaluate the efficacy of video-intuboscopic assisted tracheal intubation in a difficult intubation setting.

METHODS

In 50 pediatric patients (mean age 12.8 +/- 3.1 yr, range 6-16 yr) a grade 3 direct laryngoscopic view was simulated. Eight certified registered nurse anesthetists without experience in endoscopic intubation performed tracheal intubation on five or more patients using the video-optical intubation stylet. Time from insertion of the tube into the oral cavity until the tip had passed the vocal cords was recorded. Failed intubation was defined as intubation >60 sec, arterial oxygen saturation <92% or esophageal intubation. Subjective degree of difficulty was asked from the operators using a Likert-scale.

RESULTS

Forty-six of the 50 patients were successfully intubated within 60 sec and without arterial oxygen desaturation. In four patients, video-assisted tracheal intubation failed due to prolonged intubation time. Intubation times ranged from 10-40 sec (median 15 sec). Mean intubation time in the first patient (24.5 +/- 17.3 sec) appeared longer than for the fifth patient (20.8 +/- 10.9 sec), but the difference was not statistically significant (P=0.87). Mean estimated degree of difficulty was 3.9 +/- 2.1. Subjective estimates of difficulty increased with intubation times (P=0.001).

CONCLUSION

The video-optical intubation stylet can be considered a valuable aid for tracheal intubation in pediatric patients with a difficult airway.

Poor man's LMA: achieving adequate ventilation with a poor mask seal

PURPOSE

This report describes a technique of ventilation prior to laryngoscopy and intubation that proved to be simple, inexpensive and effective for a patient whose airway evaluation suggested difficult mask ventilation. The technique is called Poor Man's LMA.

CLINICAL FEATURES

A 60-yr-old male, measuring 170 cm, weighing 117 kg, edentulous and with a full beard, was to undergo uvulopalatopharyngoplasty. After induction of general anesthesia with a hypnotic, analgesic and non-depolarizing muscle relaxant, it was soon determined that mask bag ventilation was difficult due to an inadequate seal between the mask and the patient's full beard. To improve ventilation, an endotracheal tube was placed into the oropharynx, the lips and nose compressed by a colleague in order to prevent gas egress, and effective manual ventilation established by connecting the circle system to the endotracheal tube. Subsequent direct laryngoscopy and intubation were accomplished without incident.

CONCLUSION

The patient's clinical features made conventional mask bag ventilation difficult and inadequate. The Poor Man's LMA technique improved oxygenation and ventilation in preparation for intubation. Further investigations on the usefulness of this technique are warranted.

New equipment and techniques for airway management in trauma

A patent, unobstructed airway is fundamental in the care of the trauma patient, and is most often obtained by placing a cuffed tube in the trachea. The presence of shock, respiratory distress, a full stomach, maxillofacial trauma, neck hematoma, laryngeal disruption, cervical spine instability, and head injury all combine to increase tracheal intubation difficulty in the trauma patient. Complications resulting from intubation difficulties include brain injury, aspiration, trauma to the airway, and death. The use of devices such as the gum-elastic bougie, McCoy laryngoscope, flexible and rigid fiberscopes, intubating laryngeal mask, light wand, and techniques such as rapid-sequence intubation, manual in-line axial stabilization, retrograde intubation, and cricothyroidotomy, enhance the ability to obtain a definitive airway safely. The management of the failed airway includes calling for assistance, optimal two-person bag-mask ventilation, and the use of the laryngeal mask airway, Combitube, or surgical airway. The simulation of airway management using realistic simulator tools (e.g. full-scale simulators, virtual reality airway simulators) is a promising modality for teaching physicians and advanced life support personnel emergency airway management skills.

A multiple-hospital anaesthetic problem register: establishment of a regionally organized system for facilitated reporting of potentially recurring anaesthetic-related problems

A regionally organized system aiming to facilitate reporting and retrieval of information about potentially recurring anaesthetic-related problems has been established, covering 20 separate hospitals. Components of the system include a reporting package to facilitate use by anaesthetists in busy clinical practice; centralized clerical support; supervision by anaesthetists; reports and laminated cards supplied to the patient; and a permanently accessible database. A new classification system for difficulties in airway management has been developed as part of the system. After initial establishment, the system has been utilized by a broad cross-section of anaesthetists in the region. The first 350 reports are described. The reporting rate is approximately 0.3% of all anaesthetics given in the region. We believe the success of this system has been primarily due to features aiming to facilitate reporting, "local" ownership and supervision by clinical anaesthetists.

The difficult airway

The difficult airway, although rare, still occurs with a frequency sufficient to require that all personnel associated with airway management be familiar with methods to use when confronted with a challenging airway. Methods of airway assessment are helpful but lack adequate sensitivity and specificity. The most effective means of anticipating a difficult airway lies in an integrated approach utilizing the history, physical exam, and the patient's medical record. The most effective manner of dealing with a difficult airway involves proper anticipation, patient preparation, and the development of practical, well thought out contingency plans. Most importantly, extubation must only occur after a plan has been designed to ensure that the patient may be adequately supported in the event of a premature extubation. Certain injuries to the airway and esophagus are more common in patients in whom intubation was difficult. Such patients should be closely watched and informed about the signs and symptoms of tracheal and esophageal injury.

Validation of a simple algorithm for tracheal intubation: daily practice is the key to success in emergencies--an analysis of 13,248 intubations

A fundamental skill of the anesthesiologist is airway management. We validated a simple endotracheal intubation algorithm with a large proportion of fiberoptic tracheal intubations used for years in daily practice. Over 2 yr, 13,248 intubations (>90% of all intubations, including obstetrics and ear, nose, and throat patients) in a heterogeneous patient population at our acute care hospital were evaluated prospectively. About 80 physician and nurse anesthetists were involved. Once the indication for intubation (oral or nasal) was established, the first step was to choose between the primary conventional technique (laryngoscope with Macintosh blades) and the primary fiberoptic technique. For the conventional technique, a well defined procedure had to be followed (maximum of two attempts at intubation; if unsuccessful, switch to secondary oral fiberoptic intubation). For the primary fiberoptic technique, the anesthesiologist had to decide between nasotracheal intubation in awake patients and oral intubation in anesthetized patients. Fiberoptics were used for 13.5% of the intubations. By following our algorithm, intubation failed in 6 out of 13,248 cases (0.045%; 95% confidence interval 0.02%-0.11%). We demonstrate that a simple algorithm for endotracheal intubation, basically limited to fiberoptics as the only aid, is successful in daily practice. Only methods that are practiced daily can be used successfully in emergencies.

Airway difficulties caused by improperly applied cricoid pressure

Cricoid pressure, when properly applied, may prevent gastric regurgitation and may improve the view of laryngoscopy. When improperly applied, however, it can impede laryngoscopy and mask-ventilation. When faced with a "cannot intubate" or "cannot mask-ventilate" situation, clinicians should reevaluate the manner with which the assistant is applying cricoid pressure and must be prepared to adjust or even to release it.

Fibreoptic nasal intubation in children with anticipated and unanticipated difficult intubation

The establishment of a tracheal airway with direct laryngoscopy can be either a very difficult or an impossible task in children with congenital or acquired facial malformations. Out of 46 patients categorized as difficult tracheal intubation, fibreoptic laryngoscopy was used successfully in 44 children anaesthetized by mask with sevoflurane and oxygen or by an intravenous infusion of propofol and mask oxygenation. There were two failures (4.3%). One was due to excessive bleeding and secretions produced by the multiple attempts to intubate with direct laryngoscopy and the other failure in a patient with Pierre Robin syndrome and very small nasal passages that precluded the introduction of the endoscope. Fibreoptic laryngoscopy was successful in 37 cases (80.4%) on the first attempt to intubate and in seven (15.2%) on a second or third attempt. We conclude that fibreoptic laryngoscopy in anaesthetized children with difficult anticipated or unanticipated tracheal intubation in trained hands is a safe technique that can be lifesaving. Therefore, we urge all anaesthesia trainees to become proficient in fibreoptic tracheal intubation.

The laryngeal mask airway: a comprehensive review for the Emergency Physician

The Laryngeal Mask Airway (LMA) was developed in the 1980s, but has only recently begun to be used in Emergency Medicine. The LMA affords effective assisted ventilation without requiring endotracheal intubation or visualization of the glottis. In doing so, it is more efficacious than a bag-valve-mask apparatus, although the risk of aspiration of gastric contents persists, particularly if the device is not properly placed. The LMA also has significant potential utility in management of the difficult airway. Most reported clinical experience with the LMA has come from the operating room. This article provides an overview of the extensive potential utility of the LMA in the Emergency Department and prehospital settings as well as a comprehensive review of the pertinent advantages, disadvantages, and complications associated with its use.

Obstetric anesthesia practice in Canada

PURPOSE

To describe obstetric anesthesia in Canada as practiced in 1997: to identify practices at variance with the literature and the opinions of experts: and to identify questions for future research.

METHODS

In 1997, a detailed postal questionnaire asking about the practice of obstetric anesthesia was mailed to all 1,539 specialist anesthesiologist members of the Canadian Anaesthetists' Society residing in Canada. Nonresponders were mailed a second questionnaire three months later

RESULTS

There were 865 completed questionnaires returned for analysis (56.2%). Of these, 522 anesthesiologists practiced obstetric anesthesia (60.3%). The data were subdivided into those from anesthesiologists with a full or part-time university based practice (40.1%) and those from a community based practice (59.9%). University based and community-based anesthesiologists have very similar patterns of practice. Specific areas where anesthesia practice was different from current recommendations included: (1) information provided when obtaining consent for labour epidural analgesia, (2) use of opioids and local anesthetics for initiation of epidural analgesia, (3) use of coagulation testing in preeclampsia, (4) the common use of cutting spinal needles, (5) use of neuraxial morphine and nonsteroidal anti-inflammatory agents after Cesarean deliveries, (6) optimal treatment of neuraxial opioid side effects, (7) when to insert an endotracheal tube for general anesthesia after delivery, and (8) withdrawing epidural catheters through epidural needles.

CONCLUSIONS

This survey presents reference data on the practice of obstetric anesthesia in Canada in 1997. Anesthesiologists with university affiliation have very similar practices to those without university affiliations.

Bullard laryngoscope: Management of difficult airway in maxillofacial surgery

Difficult intubation has an incidence of 1.5-8.5%. Failed intubation occurs in 0.13-0.3% of general anaesthetics and it has been found that 30% of the mortality attributed to anaesthesia is related to difficulties in the management of the airway(1). Many techniques and instruments have been advocated in the management of difficult airways; one of these being the Bullard laryngoscope (BL). We report the management of two cases of difficult airway due to limited mouth opening using the Bullard laryngoscope.

The utility of three-dimensional computed tomography in unanticipated difficult endotracheal intubation

IMPLICATIONS

We experienced a case of unanticipated difficult intubation with direct laryngoscopy because of narrowing of the retropharyngeal air space and laryngeal vestibulum. It is suggested that three-dimensional computed tomography is useful for evaluating both the abnormality of an airway and its relationship to surrounding tissue.

Gastric distension and ventilation during laparoscopic cholecystectomy: LMA-Classic vs. tracheal intubation

PURPOSE

The standard laryngeal mask airway LMA-Classic was designed as an alternative to the endotracheal tube (ETT) or the face mask for use with either spontaneous or positive pressure ventilation. Positive pressure ventilation may exploit leaks around the LMA cuff, leading to gastric distension and/or inadequate ventilation. We compared gastric distension and ventilation parameters with LMA vs ETT during laparoscopic cholecystectomy.

METHODS

One hundred and one, ASA I-II adults scheduled for elective laparoscopic cholecystectomy were randomly assigned to LMA-Classic or ETT. Patients with BMI >30 kg x m(-2), hiatus hernia or gastroesophageal reflux were excluded. Following induction of anesthesia, an in-and-out orogastric tube was passed to decompress the stomach before insertion of the LMA (women size #4, men size #5) or ETT (women 7 mm, men 8 mm). Anesthesia was maintained with isoflurane in nitrous oxide and oxygen (FIO2 0.3-0.5), rocuronium and fentanyl. The surgeon, blinded to the type of airway, scored gastric distention 0-10 at insertion of the laparoscope and immediately before removal at the end of the surgical procedure.

RESULTS

Incidence and degree of change in gastric distension were similar in both groups. Ventilation parameters during insufflation (mean +/- SD) for LMA and ETT were: S(P)O2 98 +/- I vs 98 +/- I, P(ET)CO2 38 +/- 4 vs 36 +/- 4 mm Hg and airway pressure 21 +/- 4 vs 23 +/- 3 cm water.

CONCLUSION

Positive pressure ventilation with a correctly placed LMA-Classic of appropriate size permits adequate pulmonary ventilation. Gastric distension occurs with equal frequency with either airway device.

Augmented fiberoptic intubation

Patients who are difficult to intubate are randomly encountered. Patients who are in the postoperative period or who have suffered trauma have a greater chance of being difficult to intubate. The ability to quickly mobilize trained personnel and advanced equipment provides the best chance for a good outcome for these patients. Practice in placement of and intubation with LMAs is an important step toward providing an extensive safety net for patients needing intubation.

Emergent airway management. Indications and methods in the face of confounding conditions

Optimal airway management requires an experienced caregiver, attention to detail, and knowledge of the patient's physiology. A variety of pharmacologic agents have proved useful in obtaining a secure airway and minimizing risk to the patient. Depending on the skills of the caregiver, oral intubation has become the preferred means of airway control in most patients. Advances in technique, equipment, and pharmacology have greatly improved the art of airway management; however, there is no substitute for an experienced clinician.