The prediction of difficult intubation in obese patients using mirror indirect laryngoscopy: A prospective pilot study.

BACKGROUND: The incidence of difficult laryngoscopy and intubation in obese patients is higher than in the general population. Classical predictors of difficult laryngoscopy and intubation have been shown to be unreliable. We prospectively evaluated indirect mirror laryngoscopy as a predictor of difficult laryngoscopy in obese patients. MATERIALS AND METHODS: 60 patients with a body mass index (BMI) greater than 30, scheduled to undergo general anesthesia, were enrolled. Indirect mirror laryngoscopy was performed and was graded 1-4 according to Cormack and Lehane. A view of grade 3-4 was classified as predicting difficult laryngoscopy. Additional assessments for comparison were the Samsoon and Young modification of the Mallampati airway classification, Wilson Risk Sum Score, neck circumference, and BMI. The view obtained upon direct laryngoscopy after induction of general anesthesia was classified according to Cormack and Lehane as grade 1-4. RESULTS: Sixty patients met the inclusion criteria; however, 8 (13.3%) patients had an excessive gag reflex, and examination of the larynx was not possible. 15.4% of patients who underwent direct laryngoscopy had a Cormack and Lehane grade 3 or 4 view and were classified as difficult. Mirror laryngoscopy had a tendency toward statistical significance in predicting difficult laryngoscopy in these patients. CONCLUSIONS: This study is consistent with previous studies, which have demonstrated that no one individual traditional test has proven to be adequate in predicting difficult airways in the obese population. However, the new application of an old test - indirect mirror laryngoscopy - could be a useful additional test to predict difficult laryngoscopy in obese patients.

Learning curves of novice anesthesiology residents performing simulated fibreoptic upper airway endoscopy.

BACKGROUND: In various medical and surgical specialties, it is essential to acquire fibreoptic upper airway endoscopy skills for successful endotracheal intubation, especially when faced with a difficult airway. The aim of our study was to evaluate the learning curves of residents performing fibreoptic upper airway endoscopy in the simulation environment. METHODS: Following a standardized video and practice session, 16 residents newly enrolled in the anesthesiology program performed nasal fibreoptic endoscopy of the upper airway (endpoint being the carina) on a high fidelity simulator. Weekly 20-min sessions continued for a period of one month. Each attempt was designated as either a "success" or a "failure" based on the study participant's ability or inability to visualize the carina in ≤60 sec and with ≤five collisions with the simulated mucosal wall. Proficiency was attained when the downward graphical trend of the cumulative sum (CUSUM) analysis crossed two adjacent boundary lines, i.e., an acceptable failure rate was reached. RESULTS: The residents' mean number of attempts at fibreoptic airway endoscopy was 47 (9) with a range of 32-64. Time to visualization of the carina was 51 (36) sec. Three classical patterns of CUSUM trends were observed: proficient (n = 7); not proficient with a downward (improvement) trend (n = 3); and not proficient with an upward (worsening) trend (n = 6). The number of attempts at which proficiency was achieved varied from 27 to 58. CONCLUSION: There is a large variation in the learning curves of residents performing fibreoptic upper airway endoscopy. The training for fibreoptic airway endoscopy should be tailored to the needs of each individual.

A survey of airway training among U.S. and Canadian anesthesiology residency programs.

STUDY OBJECTIVE: To determine the current trends in airway education in academic programs. DESIGN: Survey instrument. SETTING: American academic medical center. SUBJECTS: 147 directors of American and Canadian anesthesiology residency programs. MEASUREMENTS: An invitation to complete an online questionnaire was sent. Non-responding institutions were contacted repeatedly by email and telephone to ensure a reasonable response rate. MAIN RESULTS: 88 of the 147 (60%) programs completed the survey. Forty-three respondents (49%) reported that they had formal airway rotations, and 39 respondents said that a designated titled faculty member was responsible for airway training. Didactic lecture and manikin instruction were used by more than two thirds of the programs. Documentation of supervised airway experience was recorded in 71 (82%) programs. The majority of the programs (81%) had videolaryngoscopes. A fiberoptic bronchoscope was nearly universally available, and approximately one third (34%) of graduating residents were estimated to have performed more than 25 awake fiberoptic intubations. For most techniques, the estimates of the required number of procedures to ensure competence varied widely. CONCLUSIONS: The number of programs with a formal airway management program continues to increase, and programs are incorporating newer intubation techniques. The criteria for competence have not been established.

A proposed classification of simulators.

This paper provides a coherent and comprehensive classification of simulators, using a five letter coding system, and is based on the characteristics of the user interface and the logic controller.

Review of video laryngoscopy and rigid fiberoptic laryngoscopy.

PURPOSE OF REVIEW: Recent advances in fiberoptic systems and video technology have resulted in the development of new intubation devices and techniques. A defining characteristic of rigid fiberoptic and videolaryngoscopic techniques is that glottic opening is viewed indirectly in place of direct line-of-sight. Various issues common to all instruments in this group are highlighted, and a few recently released tools are described. The aim of this article is to review material published since January 2007. RECENT FINDINGS: Indirect laryngoscopic techniques seemed to be easy to learn by both novice and experienced intubators, and can be used to teach both direct laryngoscopy and fiberoptic intubation. An adequate glottic view is generally easily obtained, which is frequently superior to that obtained by direct laryngoscopy. However, endotracheal tube insertion may be problematic, and various techniques have been developed to facilitate this procedure. Indirect laryngoscopic techniques are proving useful in situations of both anticipated and unanticipated difficult intubations, and therefore challenge the preeminence of flexible fiberoptic intubation. SUMMARY: As indirect laryngoscopic tools become more available, and clinicians become more facile in their use, the management of (potentially) difficult intubations is likely to change. Further technological advances are likely to lead to the development of even more new instruments.

Teaching without a teacher: developing competence with a Bullard laryngoscope using only a structured self-learning course and practicing on a mannequin.

STUDY OBJECTIVE: To show that a complex motor skill can be taught without requiring active expert faculty participation. DESIGN: Prospective descriptive study. SETTING: Simulation laboratory of an academic anesthesiology department. SUBJECTS: Novice users of the Bullard laryngoscope, predominantly residents. INTERVENTIONS: Novice Bullard users were presented with a PowerPoint presentation using text and pictures describing the use of the Bullard. The learners were also provided with a Bullard laryngoscope and a mannequin on which to practice. Self-learning time was not restricted. MEASUREMENTS: Learners decided for themselves when they were competent and ready for competency assessment. The assessment tool was a checklist of essential steps developed by faculty experienced in Bullard laryngoscopy. The primary end-point was successful intubation. MAIN RESULTS: All learners were deemed competent. The mean self-learning time was 14.1 minutes (SD, 3.1 min; range, 9.2-21.0 min). All subjects indicated a high level of satisfaction with the learning technique. CONCLUSIONS: Teaching a complex motor skill with no expert instruction is possible.

Assessment of recurrent laryngeal nerve during thyroid surgery with laryngeal mask airway.

OBJECTIVE: To study the feasibility of using laryngeal mask anesthesia (LMA) with bronchoscopic evaluation of recurrent laryngeal nerve (RLN) integrity when stimulated. DESIGN: Single-institution prospective case series. SETTING: A single, mid-Atlantic region academic medical center. PATIENTS: Twenty-seven adult volunteers. INTERVENTIONS: Laryngeal mask anesthesia for thyroid surgery, monitored by flexible laryngoscopy and nerve integrity testing. MAIN OUTCOME MEASURES: Success rates for LMA use in thyroid surgery, bronchoscopic visualization of laryngeal glottis, and documentation of RLN integrity following surgery. RESULTS: We report our experience on 27 consecutive cases in which LMA with RLN stimulation was used for thyroid surgery. Twenty-five of 27 patients underwent successful LMA and visual documentation of RLN integrity by bronchoscopic inspection of nerve stimulation. CONCLUSIONS: Direct visualization of vocal cords using a fiberoptic bronchoscope via an LMA provides a safe and feasible method of laryngeal assessment following thyroid dissection. Continuous real-time video monitoring may be the next step in development of this technique as a patient safety measure for thyroid and parathyroid surgery.