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RACTICE Guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints and are not intended to replace local institutional policies. In addition, Practice Guidelines developed by the American Society of Anesthesiologists (ASA) are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice Guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert and practitioner opinion, open-forum commentary, and clinical feasibility data. This document updates the “Practice Guidelines for Management of the Difficult Airway: An Updated Report by

Objectives: There is international consensus that elderly patients with head and neck cancer should be treated curatively, like younger patients. Because of common comorbidities in elderly patients, perioperative complications are likely. The McPeek postoperative outcome score was used to evaluate the success of surgical interventions in patients with head and neck cancer. Methods: We included 168 patients in the study (56 in the study group, 75 years of age or more; and 112 in the control group, less than 60 years of age). All patients underwent major surgery for head and neck cancer. Results: The median McPeek scores were 8 in the study group and 9 in the control group (p = 0.04). Regression analysis revealed that neither age (p = 0.085) nor the American Society of Anesthesiologists physical status score (p = 0.342) were independent predictors of the McPeek score. Synchronous surgical interventions (p = 0.00051) and duration of surgery (p = 0.0015) had a significant impact on McPeek score performance. Conclusions: The McPeek score seems to be an appropriate tool for comparing major surgeries for head and neck cancer in different age groups. It is possible to assess the influence of anesthetic and surgical interventions and complications that affect the length of hospitalization. The results confirm that the overall complication rate after surgery in elderly patients does not differ significantly from that in their younger counterparts. Therefore, extended surgical treatment should be offered to both age groups when no serious comorbidities are present. The postoperative outcome seems to depend on the duration and extent of the surgical intervention.

To compare the direct and indirect (video monitor) views of the glottic opening using a new Macintosh blade that is modified to provide a video image of airway structures during laryngoscopy.Prospective multicenter trial.11 university-affiliated hospitals.867 adults undergoing elective surgery requiring general anesthesia and tracheal intubation.Patients received general anesthesia and were paralyzed. Direct laryngoscopy was supervised by one of the investigators at each institution. The best possible view was obtained with a Macintosh video laryngoscope during direct vision using standard techniques such as external laryngeal manipulation and backward, upward, and rightward pressure, if necessary. The laryngoscopist then looked at the video monitor and performed any necessary maneuvers to obtain the best view on the video monitor. Thus, 2 assessments were made during the same laryngoscopy (direct naked-eye view vs video monitor view). Tracheal intubation was then performed using the monitor view. Glottic views were rated according to the Cormack-Lehane scoring system, as modified by Yentis and Lee. A questionnaire was completed for each patient.Data from 865 patients were suitable for analysis. Visualization was considered easy (Cormack-Lehane score3) in 737 patients and difficult (Cormack-Lehane score=3 or 4) in 21 for both direct and video-assisted views. In 7 patients, the view was considered easy during direct visualization yet difficult on the video monitor view. On the other hand, the view was considered difficult in 100 patients during direct visualization yet easy on the video monitor view (P0.001).Video-assisted laryngoscopy provides an improved view of the larynx, as compared with direct visualization. This technique may be useful for cases of difficult intubation and reintubation as well as for teaching laryngoscopy and intubation.

Background An unexpected difficult intubation occurs because physical examination of the airway is imperfect in predicting it. Lingual tonsil hyperplasia (LTH) is one risk factor for an unanticipated failed intubation that is not detectable during a routine oropharyngeal examination. The authors attempted to determine the incidence of LTH in unanticipated failed intubation in patients subjected to general anesthesia. Methods Thirty-three patients with unanticipated failed intubation via direct laryngoscopy were subjected to airway examinations and fiberoptic pharyngoscopy to determine the cause(s) of failure. Mouth opening, mandibular subluxation, head extension, thyromental distance, and Mallampati airway class were recorded. Fiberoptic pharyngoscopy was then performed to evaluate the base of the tongue and valleculae. Results Of these 33 patients, none had an airway examination that suggested a difficult intubation. The lungs of 12 patients were difficult to ventilate by mask. In 15 patients, airway measurements were within normal limits with Mallampati class of I or II. Ten patients had a Mallampati class III airway, 6 associated with obesity and 5 with mildly limited head extension. Among the 5 morbidly obese patients, most of the weight was distributed on the lower trunk and body. The 3 remaining patients had a thyromental distance of 6 cm or less but otherwise had a normal airway examination. The only finding common to all 33 patients was LTH observed on fiberoptic pharyngoscopy. Conclusion Lingual tonsil hyperplasia can interfere with rigid laryngoscopic intubation and face mask ventilation. Routine physical examination of the airway will not identify its presence. The prevalence of LTH in adults and the extent of its contribution to failed intubation is unknown.

RWAY MANAGEMENT is the cornerstone of safe anesthesia delivery. Endocrine disorders such as diabetes mellitus, acromegaly, obesity, a nd thyroid disorders including goiter and malignancies may adversely affect the airway and increase the risk of difficult intubation. Given the thorough review of the pathophysiology of various endocrine diseases in other parts of this monograph, this article will focus solely on how these disorders affect the airway and its management.

Background The laryngeal mask airway (LMA; LMA North America, Inc., San Diego, CA) has a well-established role in the emergency and elective treatment of patients with difficult-to-manage airways (DA). In this study, the authors report their clinical experience with the intubating LMA (LMA-Fastrach; LMA North America, Inc., San Diego, CA) in 254 patients with different types of DA. Methods The authors reviewed the anesthetic and medical records of patients with DA in whom the LMA-Fastrach was used electively or emergently at four institutions from October 1997 through October 2000. In each case, the number of insertion and intubation attempts was recorded. Success rates for blind and fiber optically guided intubation through the LMA-Fastrach were calculated, up to a maximum of five attempts per patient. Results The LMA-Fastrach was used in 257 procedures performed in 254 patients with DA, including patients with Cormack-Lehane grade 4 views; patients with immobilized cervical spines; patients with airways distorted by tumors, surgery, or radiation therapy; and patients wearing stereotactic frames. Insertion of the LMA-Fastrach was accomplished in three attempts or fewer in all patients. The overall success rates for blind and fiber optically guided intubations through the LMA-Fastrach were 96.5% and 100.0%, respectively. Conclusions The LMA-Fastrach was used successfully in a high percentage of patients who presented with a variety of DA. The clinical experience presented herein indicates that this device may be particularly useful in the emergency and elective treatment of patients in whom intubation with a rigid laryngoscope has failed and in the treatment of patients with immobilized cervical spines.

Soon after the introduction of the flexible bronchoscope into clinical medicine, anesthesiologists recognized its value in airway management. 4,14,37,38,49,71 Because of its continuous refinement, the introduction of new techniques in fiberoptic airway management, and the relative ease of exploring an airway with it, the scope of the anesthesiologist's role in airway management has been expanded. 2,16,29,32,59,72 The enormous popularity of the flexible bronchoscope in anesthesia practice has led to the publication of books and monograms devoted to its role in that setting. 43,44,53,57 The flexible bronchoscope is used for airway management more than any other intubation technique or device, even though it was not developed for this purpose nor used for the first fiberoptic tracheal intubation. A flexible fiberoptic choledochoscope was used to perform the first fiberoptic nasotracheal intubation in a patient with a difficult airway complicated by Still's disease. 38 Today, the flexible bronchoscope is used for many perioperative applications including tracheal intubation, endobronchial placement of double-lumen tubes and blockers, and evaluation of the airway: ADiagnostic 1Evaluation of a compromised airway aTumors bInfections cEpiglottitis dTracheal stenosis eLaryngeal polyps fSmoke inhalation 2Differential diagnosis of stridor 3Identification of the source of hemoptysis 4Identification of malpositioned tracheal and endobronchial tubes BTherapeutic 1Treatment of acute atelectasis 2Correcting malpositioned endotracheal tube 3Correcting malpositioned endobronchial tubes and blockers 4Tracheobronchial toilet CProblem solving 1Management of failed intubation 2Management of difficult intubation 3Management of failed positioning of endobronchial tubes and blockers 4Identification of the causes of acute hypoxemia DOther 1Fiberoptic changing of the endotracheal tube 2Checking nasogastric tube position 3Checking jet stylet position 4Evaluation for optimal time of extubation aMajor head and neck surgeries bEdema of the upper airway cEpiglottitis

Applications of the fiberoptic bronchoscope (fiberscope) in the intensive care unit setting include evaluation of the airway, trachea and bronchial intubation, aid to changing endotracheal tubes, and placement for difficult nasogastric tubing. Intubation of the awake versus the unconscious or anesthetized patient is discussed along with the devices available. Finally, success of alleviating major airway complications begins with proper training.

Patients with deep neck infections, especially those with Ludwig's angina, may die as a result of airway management mishaps. Skillful airway management is critical, but a safe method of airway control in these patients is yet to be established. We subjected patients with deep neck infections to fiberoptic tracheal intubation by using topical anesthesia to provide general anesthesia for surgical interventions. Patient characteristics and techniques for intubations were recorded on a special data-collection form. Of the 26 patients, 17 had Ludwig's angina, and 9 had other types of deep neck infections. Three patients were tracheally intubated while in the sitting position, 2 in Fowler's position, and 21 in the supine position with the head up 10 degrees-15 degrees. Tracheal intubations were successful in 25 patients: 19 nasally and 6 orally. After surgery, seven patients were kept tracheally intubated, and five patients had tracheostomies. Complications were limited to three cases of mild epistaxis and four oversedations with transient hypoxemia. Twelve patients remembered part of the procedure, and two considered it unpleasant. Tracheal intubation with a flexible bronchoscope by using topical anesthesia is highly successful in adult patients with deep neck infections. Tracheostomy using local anesthesia is recommended if fiberoptic intubation is not feasible, if the clinician is not skillful in the use of awake fiberoptic intubation, or if intubation attempts have failed.

Aspiration as a result of gastroesophageal reflux (GER) and regurgitation remains a serious potential problem in anesthetized patients. The incidence of GER with either the Esophageal Tracheal Combitube (ETC) or the laryngeal mask airway (LMA) was investigated using tracheal and esophageal pH electrodes.Following approval by the Institutional Review Board and written informed consent, 57 patients of ASA physical status I to III were randomly assigned to receive either an LMA (Group I, n = 28) or an ETC (Group II, n = 29) during general anesthesia. All patients were paralyzed and received positive pressure ventilation. Two monocrystalline antimony catheters were used for pH monitoring: one unipolar catheter with a single pH sensor for tracheal pH measurements and one bipolar catheter with proximal and distal sensors for pharyngeal and esophageal pH measurements, respectively.One episode of GER occurred in a patient in Group II, yet there were no pH changes reflected in the oropharyngeal or tracheal regions. There were 3/25 (12%) patients in Group I vs 1/25 (4%) patients in Group II that met the pH criterion for aspiration (pH below 4.0 that lasted at least 15 sec), yet no patient developed any clinical signs of aspiration. In all patients, hemodynamic and respiratory variables remained stable throughout the period of measurement (data not included).In this pilot study, the ETC appears comparable to the LMA regarding the incidence of GER and tracheal acid aspiration.

An unexpected difficult intubation occurs because physical examination of the airway is imperfect in predicting it. Lingual tonsil hyperplasia (LTH) is one risk factor for an unanticipated failed intubation that is not detectable during a routine oropharyngeal examination. The authors attempted to determine the incidence of LTH in unanticipated failed intubation in patients subjected to general anesthesia.Thirty-three patients with unanticipated failed intubation via direct laryngoscopy were subjected to airway examinations and fiberoptic pharyngoscopy to determine the cause(s) of failure. Mouth opening, mandibular subluxation, head extension, thyromental distance, and Mallampati airway class were recorded. Fiberoptic pharyngoscopy was then performed to evaluate the base of the tongue and valleculae.Of these 33 patients, none had an airway examination that suggested a difficult intubation. The lungs of 12 patients were difficult to ventilate by mask. In 15 patients, airway measurements were within normal limits with Mallampati class of I or II. Ten patients had a Mallampati class III airway, 6 associated with obesity and 5 with mildly limited head extension. Among the 5 morbidly obese patients, most of the weight was distributed on the lower trunk and body. The 3 remaining patients had a thyromental distance of 6 cm or less but otherwise had a normal airway examination. The only finding common to all 33 patients was LTH observed on fiberoptic pharyngoscopy.Lingual tonsil hyperplasia can interfere with rigid laryngoscopic intubation and face mask ventilation. Routine physical examination of the airway will not identify its presence. The prevalence of LTH in adults and the extent of its contribution to failed intubation is unknown.

Background Although bronchial reactivity can be assessed by changes in airway resistance, there is no well-accepted measure of upper airway reactivity during anesthesia. The authors used the stimulus of endotracheal tube cuff inflation and deflation to assess changes in airway reactivity in patients anesthetized with sevoflurane and desflurane. Methods Sixty-four patients classified as American Society of Anesthesiologists physical status I or II participated in this randomized, double-blind study. Patients were anesthetized with either sevoflurane or desflurane at 1.0 and 1.8 minimum alveolar concentration (MAC). The trachea was stimulated by inflating the endotracheal tube cuff. A blinded observer assessed the severity of patient response to the stimulus and changes in hemodynamic variables. The process was repeated at the second MAC treatment condition. Results At 1.0 MAC, patients anesthetized with desflurane had a more intense response and a greater likelihood of significant coughing and associated hemodynamic changes (both at P < 0.05). At 1.8 MAC, sevoflurane and desflurane both suppressed clinically significant responses to tracheal stimulation. Interrater reliability was excellent for this measure of upper airway reactivity (P < 0.001). Conclusions The assessment of the cough response to tracheal stimulation by endotracheal tube cuff inflation is a reliable and clinically meaningful measure of upper airway reactivity. At 1.0 MAC, sevoflurane is superior to desflurane for suppressing moderate and severe responses to this stimulus.

The flexible bronchoscope (FB) has been used to secure the difficult airway in pediatric patients. Difficult intubations in patients with cystic hygromas have been performed in awake patients or after the induction of general anesthesia. A recent case report acknowledges the challenges of performing intubations in pediatric patients under sedation because of their inability to fully cooperate. The following case demonstrates the two step-two fiberoptic bronchoscopic tracheal intubation performed using sedation and topical anesthesia in a neonate with a difficult airway.

Effective airway management is essential for safe administration of anesthesia and successful resuscitation of cardiac arrest patients. A new interest in the safety of airway management has emerged in the past 15 yr, signified by the introduction of new airway devices, the emergence of guidelines for managing the difficult airway, the large number of publications on the subject, and the formation of the Society for Airway Management. These strides are unmatched in any other period of 15 yr since the birth of general anesthesia in 1846. The introduction of the LMA-ClassicTM in 1988, followed by the LMAFastrachTM and the LMA-ProSealTM (The Laryngeal Mask Company (UK) Limited, Bucks, United Kingdom), has generated more than 2000 publications alone. The third edition of Principles of Airway Management is a timely publication reflecting the changes and improvements in airway management. In this new edition, Drs. Finucane and Santora present 13 chapters of clinically useful, technically oriented information. With the exception of Chapter 1, “Airway Anatomy,” all of the chapters are extensively revised and expanded. The high quality of the drawings and pictures from the second edition is preserved, and many new ones are added. The third edition is expanded, with 160 more pages than the second edition. Several chapters are worthy of special mention. A well-deserved new chapter is devoted to laryngeal mask airways. The new chapter discusses the various applications of laryngeal mask airways in airway management, their role in management of a difficult airway, and their application in specific procedures such as fiberoptic bronchoscopy during general anesthesia. I was also impressed with the chapter discussing airway evaluation. Considering space limitations, there is thorough consideration of tests thought to predict difficult direct laryngoscopy, including the significant limitations of all these techniques. The chapter addressing the difficult airway benefits from the consideration of both difficult mask ventilation and difficult intubation. Appreciation of both is critical because each presents a different scenario and requires a different route in the difficult airway algorithm of the American Society of Anesthesiologists’ Practice Guidelines for Management of the Difficult Airway. Failure of both facemask ventilation and tracheal intubation presents an extremely dangerous situation, calling for good judgment, correct selection, and skillful application of the method to avoid brain damage or death. This chapter is also enhanced by a supplemental nine-page appendix that summarizes syndromes associated with a difficult airway. Another highlight includes the chapter dealing with fiberoptic intubation, specific techniques for intubation, and preparation of a patient for awake intubation. Several tables and drawings add to the value and clarity of this chapter. One criticism I have of this text is the arrangement of some of the materials. The chapter entitled “Fiberoptic Airway Management Techniques” would be better positioned after the chapter describing “The Difficult Airway.” The discussion of the complications of tracheal intubation would more logically follow the chapter describing techniques of tracheal intubation. The LMA-ClassicTM and LMA-ProSealTM should be presented early in the chapters describing basic airway management and basic airway management equipment, reflecting their fundamental importance in current practice. The LMA-FastrachTM and flexible bronchoscope should also be briefly mentioned in the intubation chapter, because their use is now routine in intubation techniques and must be mastered in nonemergency situations. The longest chapter, “Surgical Approach to Airway Management,” includes transtracheal jet ventilation and retrograde intubation, which do not seem to belong in this chapter. One of the unique strengths of this text is the emphasis on teaching of airway skills, especially that of rigid and fiberoptic intubation. Airway-related deaths, hypoxic brain damage, unnecessary tracheostomies, other major complications, and thousands of case cancellations after failed intubation each year are unacceptably high. We need better and more serious training of individuals engaged in airway management, and this text represents an important contribution to this effort. In summary, the authors should be commended for their contribution to the understanding of the basics and the importance of airway management. This text is well written and richly illustrated, with numerous excellent references. Reading this book is strongly recommended for all those engaged in airway management, from medical students to experienced practitioners. It offers practical clinical information that is critical for safe airway management and should be a readily available reference in all acute care settings.

UNLABELLED Despite the availability of several techniques and devices for the management of the difficult airway, little information has been published regarding the prevalence of their use by anesthesiologists in the United States. To determine current practice patterns, we surveyed clinicians using a questionnaire consisting of 14 difficult airway scenarios. Anesthesiologists were requested to indicate their likely approach to anesthetic induction (e.g., awake but sedated, general anesthesia with spontaneous ventilation, general anesthesia with apnea after assuring a patent airway, or general anesthesia with apnea) and the primary device they would use to intubate (e.g., direct laryngoscopy [DL], flexible fiberoptic bronchoscope [FOB], rigid fiberoptic device, surgical airway, retrograde intubation kit, laryngeal mask airway, gum elastic bougie, or Combitube). The availability of these devices was also determined (in room at all times, available "stat," available if arranged preoperatively, or not available). The survey was mailed to 1000 randomly chosen active members of the American Society of Anesthesiologists. Second and third surveys were mailed to non responders. Four hundred seventy-two completed surveys were returned. Responses by demographic groups were compared by using chi 2 analysis. DL and FOB-aided tracheal intubation techniques were chosen for most cases by most anesthesiologists (P 10 yr of clinical experience and those older than 55 yr of age preferred DL with apneic conditions (P < 0.05). Anesthesiologists who had attended workshops within the last 5 yr had greater availability of retrograde guidewire equipment and FOBs (P < 0.05). There was little use of newer alternative airway devices. IMPLICATIONS Although the teaching of alternative methods of securing a difficult airway has become ubiquitous, most anesthesiologists rely on direct laryngoscopy and fiberoptic-aided intubation in most clinical circumstances. Although workshops in the management of the difficult airway may have resulted in increased use of the fiberoptic bronchoscope and the availability of retrograde guidewire intubation equipment, other devices have not enjoyed such an increase.

This study compared a graduated training programme with that of a traditional teaching method to facilitate the learning of the technique of fibreoptic nasotracheal intubation. Thirty-two anaesthesia trainees were randomly assigned to two groups. The graduated programme involved: practice on a bronchoscopy teaching model; exposure of the epiglottis and vocal cords in patients recovering from general anaesthesia; performance of fibreoptic nasotracheal intubation in awake sedated patients. The traditional programme involved: demonstration (on a patient) of one fibreoptic nasotracheal intubation by the instructor; performance of fibreoptic nasotracheal intubation (by the trainee) in awake sedated patients. Nasotracheal intubation was accomplished significantly more often by the trainees in the graduated programme (86 out of 96 (89.6%) v. 64 out of 96 (66.5%) (P less than 0.01). The results demonstrate that trainees who undergo a graduated training programme using simulators are initially more successful at awake fibreoptic nasotracheal intubation than those who have learned in the traditional manner, and that the conditions of the investigation were acceptable to the trainees and patients.