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At least 19 recordsLinked to original sources

Head-elevated laryngoscopy position: improving laryngeal exposure during laryngoscopy by increasing head elevation.

STUDY OBJECTIVE: The objective of this study was to determine the effect of increasing head elevation and neck flexion on the quality of laryngeal view during laryngoscopy. METHODS: Laryngoscopy with a straight blade was performed on 7 fresh human cadavers. Laryngeal views were recorded with the direct laryngoscopy video system, and the laryngoscopy angle was measured throughout the procedure with an angle finder attached to the handle of the laryngoscope. Each cadaver had laryngoscopy initiated with the head lying flat on the table and with atlanto-occipital extension. The head was then progressively elevated as much as possible (the head-elevated laryngoscopy position), increasing neck flexion and the laryngoscopy angle. Three physicians blinded to the laryngoscopy angle graded the quality of laryngeal view using the percentage of glottic opening (POGO) score. RESULTS: The laryngoscopy angle ranged from a mean of 32 degrees +/-8 degrees (1 SD) with the head flat on the table to a mean of 67 degrees +/-8 degrees with the head-elevated laryngoscopy position. The mean midposition laryngoscopy angle was 49 degrees +/-6 degrees. Comparing the 3 positions, mean POGO scores+/-1 SD significantly increased from 31%+/-10% (flat position) to 64%+/-12% (midposition) to 87%+/-13% (head-elevated laryngoscopy position). Both the midposition and the head-elevated laryngoscopy position compared with the flat position were statistically significant at a P value of less than.0001. The midposition also differed significantly from the head-elevated laryngoscopy position (P <.0007). Additionally, there was a significant linear relationship among the 3 positions (P <.0001). CONCLUSION: Increasing head elevation and laryngoscopy angle (neck flexion) significantly improves POGO scores during laryngoscopy on fresh human cadavers.

Cadaver↗

Endotracheal intubation with a gum-elastic bougie in unanticipated difficult direct laryngoscopy: comparison of a blind technique versus indirect laryngoscopy with a laryngeal mirror.

UNLABELLED: We evaluated the efficacy of intubation over a gum-elastic bougie by using either a blind technique or indirect laryngoscopy with a laryngeal mirror in patients with unexpected difficult direct laryngoscopy. In a prospective study, 60 consecutive patients with an unexpected Grade III or IV direct laryngoscopy were randomly allocated for intubation with a gum-elastic bougie either blindly (Group 1) or by indirect laryngoscopy with a laryngeal mirror (Group 2). We evaluated the failure rate of each method of intubation, complications related to either method, and the time required for intubation. Out of 725 patients evaluated over a 2-mo period, 60 patients (8.3%) had a Grade III laryngoscopy, and 30 of these were randomized into each group. There were 8 failed intubations in Group 1 compared with 1 failed intubation in Group 2 (P < 0.05). All eight failures in the blind intubation group ended with esophageal intubation. No additional complications were noted in either group. The time required for endotracheal intubation with each group was not significantly different (45 +/- 10 s versus 44 +/- 11 s). We conclude that intubation with a gum-elastic bougie had a lower failure rate using indirect laryngoscopy with a laryngeal mirror than a traditional blind technique. IMPLICATIONS: We evaluated the efficacy of intubation over a gum-elastic bougie by using either a blind technique or a laryngeal mirror. Intubation with a gum-elastic bougie had a lower failure rate using indirect laryngoscopy with a laryngeal mirror (P < 0.05) than a traditional blind technique.

Aged↗

[Diagnostic correlation between indirect laryngoscopy, fibro-laryngoscopy and microlaryngoscopy with the anatomopathological results].

We have studied 265 patients with an organical lesion of the larynx, using three different laryngoscopical methods: Indirect laryngoscopy, fibrolaryngoscopy and microlaryngoscopy. We have compared the correlation between each one and the anatomopatological diagnosis, concluding that microlaryngoscopy has the best correlation, better than the fibrolaryngoscopy and this one better than indirect laryngoscopy.

Diagnosis, Differential↗

Remifentanil vs. alfentanil for direct laryngoscopy: a randomized study comparing two total intravenous anaesthesia techniques. TIVA for direct laryngoscopy.

The ideal anaesthesia for direct laryngoscopy is profound and yet brief. The present study sought to determine whether a new anaesthetic technique based on infusion of the ultra short-acting opioid remifentanil was superior to our routine alfentanil multiple-dose technique in terms of haemodynamic stability, stress responses and recovery. A total of 58 patients were randomized to receive propofol and either remifentanil or alfentanil as part of a total intravenous anaesthesia. In the remifentanil group, systolic blood pressure during anaesthesia remained significantly lower than baseline values, while it increased significantly in the alfentanil group. None of the patients receiving remifentanil showed stress responses (hypertension, tachycardia, somatic or autonomic responses), compared to 22 patients (79%) in the alfentanil group (P < 0.0001). In the remifentanil group, hypotension or bradycardia requiring intervention arose in 5 (18%) and 3 patients (11%); neither response was seen in the alfentanil group. The period from the end of propofol infusion until extubation was 5 min longer in the remifentanil group (P < 0.0001), whereas the time from extubation until discharge was similar in the two groups. Thus, neither technique showed sufficient haemodynamic stability, and further studies are needed to determine optimal dosages of propofol and opioid.

Adolescent↗

A comparison of direct, indirect, and fiberoptic laryngoscopy to evaluate vocal cord paralysis after thyroid surgery.

After thyroidectomy, the anesthesiologist usually performs a laryngoscopy to detect laryngeal edema and nerve palsies. The goal of this study was to compare three different methods of laryngeal examination after tracheal extubation of the patients. For that purpose, between 1990 and 1995, a prospective series of 1608 patients operated for thyroidectomy has been studied. The series was divided into 4 groups. In group I (n = 200), four anesthesiologists have evaluated the efficiency of the immediate postextubation direct laryngoscopy. In group II (n = 100), one anesthesiologist has compared the direct, indirect, and flexible laryngoscopies in every patient in a fixed and timed fashion. In group III (n = 100), the four examiners have evaluated the flexible laryngoscopy at a different timing so as to eliminate the possible temporal relationship of the ease of visualization in group II. In group IV (n = 1208), the four examiners have evaluated flexible laryngoscopy, on a large scale, at any time during the 1-h stay in the recovery room. Special attention was directed to the patients with known cardiovascular diseases. Direct and indirect laryngoscopies were only effective in 76 and 73%, respectively, of the patients, whereas flexible laryngoscopy was effective in 99.6% of them. Flexible laryngoscopy was easy to perform in 96.5% of the patients versus 65 and 55% with direct and indirect laryngoscopies. Finally, variations in monitored cardiovascular parameters were significantly lower with flexible and indirect laryngoscopies than with direct laryngoscopy. These mild variations induced by flexible laryngoscopy were well tolerated by patients with known cardiovascular diseases. Flexible laryngoscopy is the best method for an immediate laryngoscopic examination after thyroidectomy.

Fiber Optic Technology↗

Diabetes mellitus and difficult laryngoscopy in renal and pancreatic transplant patients.

UNLABELLED: Limited mobility of the cervical spine or temperomandibular joint may contribute to increased difficulty of laryngoscopy in patients who have severe diabetes mellitus. The frequency of difficult laryngoscopy in diabetics undergoing renal and/or pancreatic transplants has been reported to be as high as 32%. We retrospectively reviewed the anesthetic records of all adult patients who underwent renal and/or pancreatic transplant and endotracheal intubation from January 1, 1985 to October 31, 1995. Characteristics specifically reviewed included the presence of diabetes mellitus, type of organ donor, age, gender, body mass index, previous difficult laryngoscopy, known characteristics potentially related to difficult laryngoscopy, and degree of difficulty with laryngoscopy. Laryngoscopy was graded as easy, minimally to moderately difficult, and moderately to extremely difficult to perform. Factors associated with any degree of difficult intubation were univariately assessed by using Fisher's exact test. Of 725 patients, 15 (2.1%) were identified as having difficult laryngoscopies, although all underwent successful endotracheal intubations. Factors associated with difficult laryngoscopy were diabetes mellitus (P = 0.002) and characteristics known to be related to difficult laryngoscopy (P = 0.02). These findings confirm an increase in the frequency of difficult laryngoscopy in diabetic patients undergoing renal and/or pancreatic transplant, although no laryngoscopies were rated as moderately to extremely difficult. We conclude that the frequency of difficult laryngoscopy in these diabetic patients is much lower than previous reports have suggested. IMPLICATIONS: Previous studies have suggested that airway management of many diabetic patients may be difficult. Our medical record review of patients with severe diabetes undergoing organ transplants showed that extraordinary techniques were not required to successfully manage their airways.

Adult↗

[Virtual laryngoscopy and multiplanar reformats with multirow detector CT for detection and grading of upper airway stenosis].

PURPOSE: A controlled trial was performed to compare non-invasive multislice CT (virtual laryngoscopy, axial CT slices, coronal and sagittal reformats) in the detection and grading of upper airway stenosis with fiberoptic laryngoscopy. MATERIAL AND METHODS: Multislice CT and fiberoptic laryngoscopy were used to examine 111 upper airway sections (supraglottis, glottis, subglottis, trachea) in 29 patients. CT data were acquired on a multirow detector CT (collimation 4 x 1 mm, reconstruction interval 1 mm, IV contrast) and postprocessing was performed using multiplanar reformatted images (MPR) and virtual laryngoscopy. RESULTS: All CT methods accurately detected upper airway stenosis (accuracy was 96 % for virtual laryngoscopy and MPR and 94 % for axial CT-slices). Correlation of fiberoptic and virtual laryngoscopy (r = 0.94) for grading of stenosis was closer than with sagittal reformats (r = 0.80), coronal reformats (r = 0.72), and axial CT slices (r = 0.57). Even high grade stenosis could be passed with virtual laryngoscopy that was impassable for fiberoptic laryngoscopy. CONCLUSIONS: Virtual laryngoscopy enabled better assessment of stenosis as compared to reading of axial CT slices or MPR. Virtual laryngoscopy is complementary to fiberoptic laryngoscopy and should be combined with axial CT slices and MPR readings for evaluation of the surrounding structures.

Adult↗

Oral clonidine blunts the hemodynamic responses to brief but not prolonged laryngoscopy.

STUDY OBJECTIVE: To determine whether a 300 micrograms dose of oral clonidine given 90 minutes prior to laryngoscopy and intubation provides hemodynamic protection from the stress of a brief (15-second) and/or a prolonged (45-second) laryngoscopy. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Inpatients and outpatients scheduled for general anesthesia with intubation at a university-affiliated medical center. PATIENTS: Forty patients who gave informed, written consent to receive either an oral placebo or clonidine 5 micrograms/kg (up to a maximum dose of 300 micrograms) 90 minutes prior to induction of anesthesia and to undergo either brief or prolonged laryngoscopy prior to intubation. INTERVENTIONS: The patients underwent a standardized induction sequence that included d-tubocurarine 3 mg, thiopental sodium 5 mg/kg, and succinylcholine 1.5 mg/kg. The four treatment groups (each n = 10) included (1) placebo with 15-second laryngoscopy, (2) placebo with 45-second laryngoscopy, (3) clonidine with 15-second laryngoscopy, and (4) clonidine with 45-second laryngoscopy. Heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were mechanically obtained and recorded at 1-minute intervals for 12 minutes. MEASUREMENTS AND MAIN RESULTS: There were no differences between groups in the premedication hemodynamic measurements. Within each group, maximal hemodynamic variables increased significantly over the corresponding baseline values for that group. In the 15-second, but not the 45-second, laryngoscopy, clonidine successfully blunted the maximum SBP and DBP obtained when compared with the corresponding control group. In both the 15- and 45-second clonidine groups, maximum HR was significantly lower than in the corresponding placebo groups. CONCLUSIONS: Oral clonidine, when used as a preoperative medication, affords hemodynamic protection to patients undergoing a 15-second laryngoscopy. However, the stress of a 45-second laryngoscopy may be too great or the 300 micrograms dose of clonidine too low to provide hemodynamic protection for patients in this group.

Administration, Oral↗

Difficult laryngoscopy: incidence and predictors in patients undergoing coronary artery bypass surgery versus general surgery patients.

OBJECTIVE: Cardiac surgery patients might have a higher incidence of difficult laryngoscopy than the general population because of older age, dental problems, and obesity. The authors estimated the incidence and predictors of difficult laryngoscopy in coronary artery bypass surgery patients. DESIGN: Prospective, controlled study. SETTING: University setting. PARTICIPANTS: Patients undergoing coronary artery bypass or general surgery. INTERVENTIONS: Two hundred consecutive patients undergoing coronary artery bypass graft and 444 general surgery patients, all aged >40 years, were compared for the incidence and predictors of difficult laryngoscopy, defined as a grade III or IV view. MEASUREMENTS AND MAIN RESULTS: Predictors of difficult laryngoscopy were considered mouth opening <4 cm, limited cervical mobility, thyromental distance <6 cm, protruding or partially missing upper teeth, and Mallampati classes 3 and 4. More cases of difficult laryngoscopy were recorded in cardiac patients (10% v 5.2%, p <0.023). The cardiac patients were older, mostly men, and belonged to ASA III-IV risk classes. Mallampati classes 3 and 4 were more frequent in the control group. With univariate analysis, difficult laryngoscopy correlated with 7 variables: older age, ASA-IV risk class, protruding or partially missing upper teeth, limited mouth opening, limited neck movement, thyromental distance <6 cm, and diabetes mellitus. Multivariate analysis adjusted for propensity score identified older age (odds ratio = 1.05/yr, 95% confidence interval = 1.005-1.09, p < 0.03) and limited neck movement (odds ratio = 9.5, 95% confidence interval = 2.2-41, p < 0.003), but not cardiac surgery per se, as independent predictors of difficult laryngoscopy. CONCLUSIONS: Difficult laryngoscopy was more frequent in cardiac surgery patients (10% v 5.2%). Older age and limited neck movement, but not cardiac surgery per se, were independent predictors of difficult laryngoscopy.

Adult↗

Left-molar approach improves the laryngeal view in patients with difficult laryngoscopy.

BACKGROUND: The molar approach of laryngoscopy is reported to improve glottic view in sporadic cases of difficult laryngoscopy. The authors studied the effect of molar approaches and optimal external laryngeal manipulation (OELM) using the Macintosh blade. METHODS: A series of 1,015 adult patients who underwent general anesthesia and tracheal intubation was studied. Laryngoscopy was carried out using a Macintosh no. 3 or 4 standard blade. Three consecutive trials of direct laryngoscopy using the midline and left- and right-molar approaches were carried out under full muscle relaxation with optimal head and neck positioning. The best glottic views were recorded for each approach with and without OELM. RESULTS: Difficult laryngoscopy with a midline approach accounted for 6.5% (66 cases) before OELM and 1.97% (20 cases) after OELM. A left-molar approach with OELM further reduced difficult laryngoscopy to seven cases (P < 0.001 vs. midline approach with OELM); a right-molar approach with OELM reduced difficult laryngoscopy to 18 cases (P = 0.48). CONCLUSIONS: The left-molar approach with OELM improves the laryngeal view in patients with difficult laryngoscopy.

Adolescent↗

Reducing the risks of laryngoscopy in anaesthetised infants.

We have evaluated the use of oxygen insufflation during laryngoscopy with an Oxyscope laryngoscope blade compared to conventional laryngoscopy for maintenance of transcutaneous PO2 during intubation of anaesthetised, spontaneously breathing infants. Twenty healthy children aged between 1 and 24 months were anaesthetised with halothane in oxygen. Laryngoscopy and intubation were performed in a double-blind fashion using a Miller No. 1 Oxyscope blade either with or without oxygen insufflation. Transcutaneous oxygen tension, arterial pressure and heart rate were measured before and after laryngoscopy, and duration of laryngoscopy was recorded. Transcutaneous oxygen tension decreased by 7.1% (SD 6.1%) when oxygen insufflation was used, compared to 33.0% (SD 15.1%) without oxygen insufflation (p less than 0.0001). There were no significant differences in mean duration of laryngoscopy or patient age. We conclude that oxygen insufflation during laryngoscopy and intubation of spontaneously breathing, anaesthetised infants effectively minimises the decrease in transcutaneous oxygen tension from pre-laryngoscopy levels, and makes instrumentation of the airway safer.

Anesthesia, Inhalation↗

Local anesthetic administration for awake direct laryngoscopy. Are glossopharyngeal nerve blocks superior?

BACKGROUND: Glossopharyngeal nerve (GPN) blocks may provide reliable analgesia for awake direct laryngoscopy, although this has not been evaluated prospectively. This study was designed to determine if GPN blocks provide a superior route of local anesthetic administration for awake direct laryngoscopy as measured by hemodynamic, gag, and subjective pain responses. METHODS: A prospective, randomized, single-blinded, crossover design was used. All participants (n = 11) were anesthesiologists. Three routes of local anesthetic administration were evaluated: 2 min of 2% viscous lidocaine swish and gargle (S&G); S&G combined with 10% lidocaine spray (S&G/spray); and S&G combined with 1% lidocaine bilateral GPN blocks (S&G/block; anterior tonsillar pillar method). Five minutes after the local anesthetic was administered, laryngoscopy was performed and sustained for 20 s. Noninvasive hemodynamic measurements and serum lidocaine concentrations were determined. Visual analogue scale scores and a poststudy questionnaire were used to assess participants' ability to tolerate local anesthetic administration and laryngoscopy and their choice for use in clinical practice. RESULTS: No significant hemodynamic changes were observed, although there was a modest increase (< 15%) in heart rate in the S&G/block group in the first minute after laryngoscopy. Serum lidocaine concentrations were higher (P < 0.05) in the S&G/block group at 5 and 10 min (0.5 +/- 0.1 and 1.0 +/- 0.2 microgram/ml) compared with the S&G group. Participants' visual analogue scale scores, which assessed their ability to tolerate laryngoscopy, showed that S&G (5.4 +/- 0.9) resulted in more discomfort (P < 0.05) than either S&G/spray (3.5 +/- 0.9) or S&G/block (3.3 +/- 0.7). The laryngoscopist's visual analogue scale scores, which assessed the ease of visualization, revealed a trend (P < 0.08) toward less coughing and gagging with S&G/spray (1.8 +/- 0.9) compared with S&G (4.0 +/- 1.3) and S&G/block (3.7 +/- 1.1). Oropharyngeal discomfort lasting 24 h or more was reported by 91% of participants after S&G/block, whereas no participant reported oropharyngeal discomfort after S&G or S&G/spray. Significantly more participants (73%) indicated their preference for using S&G/spray in future clinical practice compared with S&G (P < 0.01) and S&G/block (P < 0.05). CONCLUSIONS: Glossopharyngeal nerve blocks do not provide a superior route of local anesthetic administration for awake direct laryngoscopy. Two minutes of 2% viscous lidocaine S&G followed by 10% lidocaine spray was the anesthetic route preferred by participants and laryngoscopists.

Anesthetics, Local↗

A comparison of the stress response to laryngoscopy. The Macintosh versus the McCoy blade.

The cardiovascular changes and catecholamine concentrations were compared in 20 patients before and after laryngoscopy with either the Macintosh or the McCoy laryngoscope blades. Following induction with fentanyl and thiopentone and muscle relaxation with vecuronium the vocal cords were visualised for 10 s with either the Macintosh or McCoy blade, chosen at random. Heart rate, arterial blood pressure and plasma noradrenaline and adrenaline concentrations were measured before, and at, laryngoscopy, and 1, 3 and 5 min later. There was a significant increase in both heart rate (33%) and arterial blood pressure (27%) after laryngoscopy using the Macintosh blade (p < 0.01). Use of the McCoy blade did not result in any significant change in either heart rate or arterial blood pressure. There was a slight increase (p > 0.05) in plasma noradrenaline concentrations using the Macintosh blade which persisted for 5 min after laryngoscopy. This was not observed with the McCoy blade. There was no change in plasma adrenaline concentrations with either blade during the 5 min after laryngoscopy when compared to the values before laryngoscopy. It is concluded that the stress response to laryngoscopy is less marked with the use of the McCoy blade and is probably due to a reduction in the force necessary to obtain a clear view of the larynx.

Adolescent↗

Hemodynamic and catecholamine responses to laryngoscopy with vs. without endotracheal intubation.

To study the relationship between the intensity of the stimulus exerted against the base of the tongue during direct laryngoscopy and the magnitude of associated hemodynamic and catecholamine responses, a study was conducted in 40 ASA I or II patients. Laryngoscopy lasting 40 s was performed with a size 3 Macintosh blade connected to a force-displacement transducer. The intensity of the stimulus exerted during laryngoscopy is expressed by the product of its average force (N) and duration (s) and given as impulse in Ns. Highly significant relationships were found between the impulse during laryngoscopy and the maximal hemodynamic and catecholamine responses. Also, when laryngoscopy was followed by orotracheal intubation, significant relationships were found with steeper slopes of the regression lines for systolic blood pressure, heart rate and plasma epinephrine concentrations. A more rapid regression of hemodynamic data was seen in intubated patients, whereas their plasma catecholamine concentrations regressed more slowly. The mechanisms of the responses to laryngoscopy and orotracheal intubation are proposed to be by somato-visceral reflexes. Stimulation of proprioceptors at the base of the tongue during laryngoscopy induces impulse-dependent increases of systemic blood pressure, heart rate and plasma catecholamine concentrations. Subsequent orotracheal intubation recruits additional receptors that elicit augmented hemodynamic and epinephrine responses as well as some vagal inhibition of the heart.

Adult↗

The modified Cormack-Lehane score for the grading of direct laryngoscopy: evaluation in the Asian population.

The use of a modified Cormack-Lehane scoring system (MCLS) of laryngoscopic views, as previously introduced in the Western population, was investigated during direct laryngoscopy in the Asian population. We studied the distribution of the different grades of MCLS, the predictive factors and rate of difficult laryngoscopy, and the association with difficult intubation. Six hundred and five patients requiring tracheal intubation during general anaesthesia were prospectively studied. The optimal views during direct laryngoscopy were scored using the 5-grade MCLS system. The distribution of the laryngoscopy scores was 73.9% Grade 1 (full view of the vocal cords), 21.0% Grade 2A (partial view of the vocal cords), 3.3% Grade 2B (only the arytenoids and epiglottis seen), 1.6% Grade 3 (only epiglottis visible) and 0.2% Grade 4 (neither the epiglottis nor glottis seen). External laryngeal pressure was necessary in 45.3% of cases to optimize laryngoscopic views. Grade 2B was associated with significantly higher incidence of difficult intubation compared with Grade 2A (65% vs 13.4%). The rates of difficult laryngoscopy and intubation were 5.1% and 6.9% respectively. The Mallampati classification and thyromental distance were associated with low predictive value for difficult laryngoscopy. The MCLS better delineates the difficulty experienced during laryngoscopy than the original Cormack-Lehane grading

Adolescent↗

Videotape feedback in teaching laryngoscopy.

PURPOSE: To evaluate if videotape feedback provides educational insights for students learning laryngoscopy that they would not otherwise perceive. METHODS: Twenty-six medical students were videotaped while performing laryngoscopy for oral intubation. Before and after reviewing their performance on the videotape, they answered a standardized questionnaire assessing the adequacy of positioning, head movement during laryngoscopy, degrees of neck flexion and head extension, time elapsed, and whether the laryngoscope contacted the upper lip or teeth. After the review, they were asked if being videotaped was distracting, whether it provided new instructional insights and, if so, which was most important. RESULTS: Only 4% of students felt that initial head and neck positioning was suboptimal and this increased to 38% after videotape review (P = 0.029). The perceived inadequacy of positioning seemed related to initial overestimation of head extension (34.0 +/- 15 degrees) compared with that seen on videotape (21.5 +/- 13.5 degrees, P = 0.003). The estimated duration of laryngoscopy was underestimated (55 +/- 32 sec vs. 75 +/- 29 sec, P = .024) before videotape review. Although 26.9% (7/26) of students admitted feeling distracted by the video camera, all felt the experience had educational value. CONCLUSION: Videotape feedback changed students' perception of how they performed laryngoscopy. In particular, head extension was overestimated and duration of laryngoscopy underestimated.

Anesthesiology↗

Prediction of prolonged laryngoscopy.

Duration of laryngoscopy must be kept as short as possible to prevent disturbances of oxygenation and ventilation. Because the factors associated with prolonged laryngoscopy are not well known, we studied 1000 patients undergoing tracheal intubation under general anaesthesia to determine the possible effects of their characteristics on the incidence of prolonged laryngoscopy (defined as lasting longer than 15 s). Multiple logistic regression analysis was performed to determine the odds ratio for significant factors. Prolonged laryngoscopy occurred in 158 patients (15.8%). Six characteristics were determined as risk factors for a prolonged laryngoscopy: weight > 80 kg [OR 3.7 (95% CI 1.9-7.1)]; tongue protrusion < 3.2 cm [OR 2.0 (1.0-4.2)]; mouth opening < 5 cm [OR 4.3 (2.1-8.9)]; upper incisor length > 1.5 cm [OR 4.2 (2.0-8.6)]; Mallampati class > 1 [OR 10.0 (7.1-14.6)]; and head extension < 70 degrees [OR 7.1 (3.8-13.6)]. The presence of three of these factors predicted prolonged laryngoscopy with a sensitivity of 0.72 and a specificity of 0.91

Adult↗