Laryngeal View Research Articles

Comparison of Bullard laryngoscope and short-handled Macintosh laryngoscope for orotracheal intubation in pediatric patients with simulated restriction of cervical spine movements

To compare time to intubation, time to optimal laryngoscopy, best laryngeal view, and success rate of intubation with pediatric Bullard laryngoscope and short-handled Macintosh laryngoscope in children being intubated with neck stabilization. Securing airway of a patient with restricted cervical spine movement has been a challenge faced by anaesthesiologists around the world. Macintosh laryngoscope with manual inline stabilization is most commonly used. Bullard laryngoscope is also useful in this situation as minimal neck movement occurs with its use. Forty patients, ASA I or II, aged 2-10 years, were enrolled in this prospective, controlled, and randomized study. Patients were randomly allocated to one of two groups: Group MB (first laryngoscopy using short-handled Macintosh laryngoscope followed by pediatric Bullard laryngoscope) and Group BM (first laryngoscopy using pediatric Bullard laryngoscope followed by short-handled Macintosh laryngoscope) with manual inline stabilization after induction of anesthesia and paralysis. Trachea was intubated orally using the second equipment. Laryngeal view when obtained was always Grade 1 with Bullard laryngoscope (38/38) when compared to Macintosh laryngoscope [Grade 1 (10/40)]. The mean time to laryngoscopy (and intubation) was shorter with Macintosh laryngoscope [15.53 s (38.15 s)] than Bullard laryngoscope [35.21 s (75.71 s)], respectively. Success rate of intubation was higher with Macintosh laryngoscope (100%) when compared to Bullard laryngoscope (70%). Laryngoscopy and intubation is faster using a short-handled Macintosh laryngoscope with a higher success rate compared to pediatric Bullard laryngoscope in pediatric patients when manual inline stabilization is applied.

Superior glottic views with the GlideScope® and Airtraq® laryngoscopes compared with an anterior commissure laryngoscope

To the Editor, In the unanticipated difficult airway, an anesthesiologist or otolaryngologist may perform direct laryngoscopy with a rigid anterior commissure laryngoscope. There have been case reports of using the anterior commissure laryngoscope for laryngoscopic rescue in difficult airways. We describe a case in which the view we obtained using two different video laryngoscopes was improved over that seen by an experienced otolaryngologist using an anterior commissure laryngoscope and over that seen by an anesthesiologist using a direct laryngoscope. This observation provides anecdotal support for the role of video laryngoscopy as an early rescue device when direct laryngoscopy affords an inadequate laryngeal view. This report is presented with the written consent of the patient. A 41-yr-old man presented with a recurrence of a squamous cell carcinoma of the tongue. On this occasion, we planned a diagnostic panendoscopy tracheostomy, bilateral neck dissection, composite mandibular resection, and reconstruction. Twelve months earlier, the patient had undergone a panendoscopy, bilateral neck dissection, mandibulotomy, partial glossectomy, and a free forearm flap to the floor of the mouth. Seven months later, a recurrence prompted cisplatin chemotherapy and irradiation with 70 Gy delivered in 35 fractions over seven weeks. The anesthesia chart from the first operation revealed no problems with bag-mask ventilation; direct laryngoscopy offered a Cormack-Lehane (C/L) grade 1 laryngeal view. The patient’s airway assessment prior to the second operation revealed an obvious flap reconstruction of the right tongue, modified Mallampati 2 view, mouth opening greater than three finger breadths, and normal neck flexion with slightly restricted extension. He had full dentition and a prominent overbite but could just approximate his maxillary and mandibular incisors. His anterior neck was swollen and firm to the touch. His body mass index was 21 kg m, and he denied any gastro-esophageal reflux. We felt that direct laryngoscopy would be difficult, but not bag-mask ventilation. Anesthesia was induced with midazolam 2 mg, remifentanil 40 lg, propofol 150 mg, and succinylcholine 100 mg iv. Following induction of anesthesia bag-mask, ventilation was easily achieved. The staff otolaryngologist inserted the anterior commissure laryngoscope as part of the panendoscopy. Since this was achieved with some difficulty, the surgeon introduced an Eschmann Tracheal Tube Introducer (Smiths Medical International Ltd, Hythe, Kent, UK) into the patient’s trachea over which an 8-mm (internal diameter) endotracheal tube was advanced. The best laryngeal view obtained with the anterior commissure laryngoscope, by using external laryngeal pressure and considerable force, was a C/L 2-B. Once a tracheostomy had been performed, three different laryngoscopes were compared by one of the authors (S.K.). Direct laryngoscopy using a Macintosh #3 provided a C/L 3 view. The Airtraq Optical Laryngoscope (Prodol Meditec, Viscaya, Spain) and the GlideScope Cobalt Advanced Video Laryngoscope (AVL) (Verathon Medical, Bothell, WA, USA), both indirect laryngoscopes, provided better views compared with the previous two laryngoscopes. No Electronic supplementary material The online version of this article (doi:10.1007/s12630-010-9413-2) contains supplementary material, which is available to authorized users.

Failure to predict difficult tracheal intubation for emergency caesarean section

Difficult tracheal intubation following induction of general anaesthesia for caesarean section is a cause of morbidity and mortality. Our aim was to evaluate five bedside predictors that might identify women with potential intubation difficulty immediately prior to emergency caesarean section. Women requiring emergency caesarean section with general anaesthesia and tracheal intubation who had been assessed by the same experienced anaesthesiologist preoperatively were included in this study. Mallampati score, sternomental distance, thyromental distance, interincisor gap and atlantooccipital extension were all measured. The same anaesthesiologist performed laryngoscopy and graded the laryngeal view according to Cormack and Lehane. Exact logistic regression was used to identify significant independent predictors for difficult intubation (Cormack and Lehane grades ≥ 3) with two-sided P value less than 0.05 considered as significant. In 3 years, 239 women were recruited. Cormack and Lehane grades of 2 or less (easy) were found in 225 and grade of at least 3 (difficult) in 14 women. Patients' characteristics (age, height, weight, BMI or weight gain) were not significantly associated with difficulty of intubation. The incidence of difficult intubation was 1/17 women [95% confidence interval (CI) from 1/31 to 1/10]. A positive result from any of the five predictors combined had a sensitivity of 0.21 (95%CI 0.05-0.51), a specificity of 0.92 (95%CI 0.88-0.96), a positive predictive value of 0.15 (95%CI 0.032-0.38) and a negative predictive value of 0.95 (95%CI 0.91-0.97) for a Cormack and Lehane grade of at least 3 at laryngoscopy. Airway assessment using these tests cannot be relied upon to predict a difficult intubation at emergency caesarean section as the low sensitivity means that 79% (95%CI 49-95) of difficult intubations will be missed.

Part 8: Advanced life support: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations

Part 8: Advanced life support: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations

Comparison of three videolaryngoscopes: Pentax Airway Scope, C‐MAC™, Glidescope® vs the Macintosh laryngoscope for tracheal intubation*

We compared the intubating characteristics of the Pentax Airway Scope, the C-MAC and the Glidescope with those of the Macintosh laryngoscope in 400 patients without predictors of difficult intubation. We found shorter intubation times with the Airway Scope (mean (SD) 20.6 (11.5) s) compared with the C-MAC (31.9 (17.6) s) and Glidescope (31.2 (15.0) s), p < 0.001. The median (IQR [range]) score for ease of intubation was significantly lower (better) with the Airway Scope (0 (0-8.75 [0-60])) than with the C-MAC (10 (0-20 [0-90])) or Glidescope (0 (0-20 [0-80])), p < 0.001. Ease of blade insertion in the C-MAC (0 (0-0 [0-30])) was superior to that of the Airway Scope (0 (0-0 [0-70])), Macintosh (0 (0-0 [0-80])) or Glidescope (0 (0-10 [0-60])), p = 0.006. More patients had a grade 1 laryngeal view with the Airway Scope (97%) compared with the C-MAC (87%), Glidescope (78%), or Macintosh (58%), p < 0.001. There were no grade 3 laryngeal views with the Airway Scope. The three videolaryngoscopes had comparable first attempt successful intubation rates: 95% for the Airway Scope, 93% for the C-MAC and 91% for the Glidescope.

Laryngoscopic techniques to assess vocal cord mobility following thyroid surgery

Assessment of vocal cord mobility using Macintosh laryngoscope is frequently performed after extubation following thyroid surgery to rule out laryngeal nerve palsy. This study compared patient comfort and assessment accuracy of post-operative vocal fold mobility with Macintosh laryngoscope and fibreoptic endoscope. One hundred four physically fit patients undergoing thyroid surgery were included for the study. Tele-laryngoscopy was done to rule out pre-existing vocal cord palsy. Direct laryngoscopy (DL) was performed to each patient after extubation, followed by nasal fibreoptic endoscopy (NFE) to assess the vocal cord mobility. Tele-laryngoscopic assessment was repeated after 1 week to compare the DL and NFE findings. Patient reactivity score (PRS) and haemodynamic parameters were recorded with each technique. Macintosh laryngoscope could pick up 4 (50% sensitivity and 88% specificity) and fibreoptic endoscope 7 (87.9% sensitivity and 98.9% specificity) out of the 8 vocal cord palsies identified by tele-laryngoscopy. Patients had significant discomfort during DL (PRS median 3) when compared with NFE and tele-laryngoscopy (PRS median 2), P<0.05. Grade 1 view of larynx in 92.1% patients during intubation worsened to grade 2 (76.3%) and grade 3 (15.8%) during extubation with DL, and a significant rise in mean arterial pressure and heart rate was observed from the baseline value till 5 min and when compared with NFE (P<0.05). NFE provides accurate assessment of vocal fold mobility with reasonable patient comfort in the immediate post-operative period. Macintosh laryngoscope fails to give optimum visualization and predisposes the patient to significant discomfort and stress.

Cormack–Lehane classification revisited

BackgroundThe Cormack–Lehane (CL) classification is broadly used to describe laryngeal view during direct laryngoscopy. This classification, however, has been validated by only a few studies reporting inconclusive data concerning its reliability. This discrepancy between widespread use and limited evidence prompted us to investigate the knowledge about the classification among anaesthesiologists and its intra- and inter-observer reliability. MethodsOne hundred and twenty interviews were performed at a major European anaesthesia congress. Participants were interviewed about their general knowledge on grading systems to classify laryngeal view during laryngoscopy and were subsequently asked to define the grades of the CL classification. Inter- and intra-observer reliabilities were tested in 20 anaesthesiologists well familiar with the CL classification, who performed 100 laryngoscopies in a full-scale patient simulator. ResultsAlthough 89% of interviewed subjects claimed to know a classification to describe laryngeal view during laryngoscopy, 53% were able to name a classification. When specifically asked about the CL classification, 74% of the interviewed subjects stated to know this classification, whereas 25% could define all four grades correctly. In the simulator-based part of the study, inter-observer reliability was fair with a κ coefficient of 0.35 and intra-observer reliability was poor with a κ of 0.15. ConclusionsThe CL classification is poorly known in detail among anaesthesiologists and reproducibility even in subjects well familiar with this classification is limited.

Difficulties with Gum Elastic Bougie Intubation in an Academic Emergency Department

Background The difficulties with gum elastic bougie (GEB) use in the emergency department (ED) have never been studied prospectively. Objectives To determine the most common difficulties associated with endotracheal intubation using a GEB in the ED. Methods We conducted a prospective, observational study of GEB practices in our two affiliated urban EDs with a 3-year residency training program and an annual census of 150,000 patients. Laryngoscopists performing a GEB-assisted intubation completed a structured data form after laryngoscopy, recording patient characteristics, grade of laryngeal view (using the modified Cormack-Lehane classification), reason for GEB use, and problems encountered. Data were analyzed using standard statistical methods and 95% confidence intervals. Results A GEB was used for 88 patients. The overall success rate was 70/88 (79.6%; 95% confidence interval [CI] 71.1–88.0%). The GEB failure rate of the first laryngoscopist was 25/88 (28.4%; 95% CI 21.0–40.3%), with the two most common reasons being: inability to insert the bougie past the hypopharynx in 13 (52%; 95% CI 32.4–71.6%) and inability to pass the endotracheal tube over the bougie in six (24%; 95% CI 7.3–40.7). Conclusions The GEB is a helpful rescue airway device, but emergency care providers should be aware that failure rates are relatively high at a teaching institution.

The GlideScope for tracheal intubation in patients with grade IV modified Cormack and Lehane

The GlideScope for tracheal intubation in patients with grade IV modified Cormack and Lehane

A comparison of direct laryngoscopic views depending on pillow height

This study was conducted to determine the optimal pillow height for the best laryngoscopic view. Fifty patients were enrolled and preanesthetic airway evaluations were recorded. After induction of anesthesia, the Macintosh 3 blade was used for direct laryngoscopy without a pillow or with a pillow 3, 6, or 9 cm high in randomized order while the laryngeal view was imaged continuously on a monitor of the integrated video system. The best direct laryngoscopic view was sought for in each condition and graded by one anesthesiologist. The correlations between the preanesthetic airway assessments and the pillow height providing the best laryngoscopic view were analyzed. The laryngoscopic view with the 9-cm pillow was significantly superior to that with other pillows and without a pillow (P < 0.001). The incidence of difficult laryngoscopy (Cormack and Lehane grade 3) was 16% without a pillow. In these cases, laryngoscopic views were improved with a 9-cm pillow. In five patients with a short neck (<15 cm), better laryngoscopic view was observed with a 3- or 6-cm pillow compared with the 9-cm pillow. Neck length had a significant correlation (rho = 0.326, P = 0.027) with the pillow height providing the best laryngoscopic views. We recommend the use of a 9-cm pillow during direct laryngoscopy in the sniffing position. In contrast, pillows <9 cm appear to be advantageous in short-necked patients.

Cricoid pressure and laryngeal manipulation in 402 pre-hospital emergency anaesthetics: Essential safety measure or a hindrance to rapid safe intubation?

Objectives This is the first study to look at the effects of cricoid pressure/laryngeal manipulation on the laryngeal view and intubation success in the emergency or pre-hospital environment. Cricoid pressure is applied in the hope of reducing the incidence of aspiration. However the technique has never been evaluated in a randomized trial and may adversely affect laryngeal view. In order to improve intubating conditions cricoid pressure may be released and the larynx manipulated into a more favourable position. Methods We carried out a prospective observational study to evaluate the effects of cricoid pressure and laryngeal manipulation on laryngeal view in our physician led pre-hospital trauma service. Results 402 patients were included over a 16-month period. We intubated 98.8% patients on the first or second attempt. In 61 intubations (in 55 patients, 13.6%) the larynx required manipulation to facilitate intubation. In 22 intubations cricoid pressure was removed with the laryngeal view improving in 50%. Bimanual laryngeal manipulation was used in 25 intubations and the larynx better visualised in 60% of these. Backwards upwards rightwards pressure was applied to the larynx in 14 intubations and the laryngeal view improved in 64%. Two patients regurgitated when cricoid pressure was released. Both had prolonged periods of bag valve mask ventilation and difficult intubations. Discussion The results suggest that cricoid pressure should be removed if the laryngeal view obtained is not sufficient to allow immediate intubation. Further manipulation of the larynx is likely to improve the chances of successful tracheal tube placement.

Evaluation of the upper lip bite test in predicting difficult laryngoscopy

Study Objective To evaluate the accuracy of the upper lip bite test (ULBT) in predicting difficult laryngoscopy. Design Prospective, observational outcome study. Setting Operating room of a large tertiary-care academic medical center. Patients 6,882 consecutive adult, ASA physical status I, II, III, IV, and V patients, scheduled for procedures in all surgical specialties. Interventions Upper lip bite test class was determined for all patients preoperatively. Measurements The Cormack & Lehane grade of laryngeal view was determined at endotracheal intubation. Main Results Only 171 patients had ULBT class III, predicting a difficult laryngoscopy, while 173 patients presented with a Cormack & Lehane grade of 3 or 4. Of the 173, 14 patients had a previous ULBT class of III. Sensitivity and positive predictive value of the ULBT were 8.1% and 8.2%, respectively. Conclusions The ULBT is a poor predictor of difficult laryngoscopy when used as the single bedside screening test in a North American patient population. Its use cannot be recommended.

A New Maneuver for Endotracheal Tube Insertion During Difficult Glidescope Intubation

The GlideScope Video Laryngoscope (Verathon, Bothell, WA) is a video laryngoscopy system that can be used for routine intubation, but is also commonly used as an alternative for difficult or failed airways. Previous reports have identified a very high incidence of grade 1 and grade 2 Cormack-Lehane glottic views, but despite these high-grade views, intubation is sometimes difficult due to the angle of insertion and shape of the endotracheal tube. Several maneuvers have been reported to increase the likelihood of successful endotracheal tube placement in these uncommon cases of failure. We report the case of a patient who could not be intubated with the GlideScope despite an easily obtained grade 1 laryngoscopic view. The impediment to intubation was identified as a sharp angulation of the trachea with respect to the larynx, such that the trachea formed a steep posterior angle with the laryngeal/glottic axis. Intubation was achieved using a previously unreported maneuver, in which the endotracheal tube with a sharply curved malleable stylet was inserted through the glottis, and then rotated 180 degrees to permit passage down the trachea. We believe that this maneuver may be useful in other cases of failed GlideScope intubation, when a high-grade laryngeal view is obtained but tube passage is not possible due to a sharp posterior angulation of the trachea.

Comparison of the laryngeal view during intubation using Airtraq and Macintosh laryngoscopes in patients with cervical spine immobilization and mouth opening limitation

BackgroundFor patients suspicious of cervical spine injury, a Philadelphia cervical collar is usually applied. Application of Philadelphia cervical collar may cause difficult airway. The aim of this study was to evaluate the laryngeal view and the success rate at first intubation attempt of the Airtraq and conventional laryngoscopy in patients with simulated cervical spine injury after application of a Philadelphia cervical collar.MethodsAnesthesia was induced with propofol, remifentanil, and rocuronium. After a Philadelphia cervical collar applied, patients were randomly assigned to tracheal intubation with an Airtraq (Group A, n = 25) or with conventional laryngoscopy (Group L, n = 25). Measurements included intubation time, success rate of first intubation attempt, number of intubation attempts, and percentage of glottic opening (POGO) score. Mean blood pressure and heart rate were also recorded at baseline, just before and after intubation.ResultsThe success rate of the first attempt in Group A (96%) was significantly greater than with the Group L (40%). POGO score was significantly greater in Group A (84 ± 20%) than in Group L (6 ± 11%). The duration of successful intubation at first tracheal intubation attempt and hemodynamic changes were not significantly different between the two groups.ConclusionsThe Airtraq offers a better laryngeal view and higher success rate at first intubation attempt in patients who are applied with a Philadelphia cervical collar due to suspicion of cervical spine injury.

Jaw Thrust Improves the Fiberoptic Laryngeal View during Fiberoptic Nasotracheal Intubation

Jaw Thrust Improves the Fiberoptic Laryngeal View during Fiberoptic Nasotracheal Intubation

Which laryngeal mask for fiberoptic-aided wire-guided catheter exchange tracheal intubation? The Classic-LMATM or the Proseal-LMATM: a mannequin study

Study Objective: To compare the ease of use, operator preference, time to completion, and failure rates while performing a fiberoptic-aided wire-guided airway exchange tracheal intubation through the the LMA-Classic TM and LMA-Proseal .Design: Prospective, randomized trialSetting: SimulationInterventions: Twenty-five participants of various experience grades performed four intubations each, one hundred intubations total, on an AirSim TM airway trainer through a #3 laryngeal mask using a fiberoptic endoscope and an Arndt Airway Exchange Catheter Set.Measurements: Laryngeal view after LMA insertion was graded by one of the investigators. The time to intubation and any intubation failures were recorded. Participants were asked to rate the ease of performing the intubation through each LMA and which device they preferred.Main Results: Intubation was reported to be easier through the cLMA than the pLMA. Consequently, participants preferred the cLMA for use as an airway conduit. However, the time to completion and failure rates were essentially the same in all groups. First attempt intubation success rate was 92% overall.Conclusion: Fiberoptic-aided wire-guided catheter exchange intubation can be performed successfully through either the cLMA or the pLMA. Personal experience with each device should dictate which device is chosen initially. GRANTS, SPONSORS, AND FUNDING SOURCES The AirSim TM airway trainer used in this study was supported by intramural departmental funds

2009 in Review

2009 in Review

Tracheal intubation with the AirwayScope™ videolaryngoscope using straight vs curved reinforced tubes

To the Editor, The AirwayScope (AWS-S100; IMI Co., LTD., Koshigaya Saitama, Japan) is proposed as an alternative to the classical Macintosh laryngoscope for tracheal intubation in patients with cervical spine instability and/or neck stiffness, because it offers a better laryngeal view with less cervical spine movement. Its introducer, the INTLOCK, gives the straight reinforced tube a downward orientation, whereas the curved tube points upwards. Therefore, intubation difficulties may be more frequent with the straight tube because of more likely impingement with the arytenoids (Fig. 1). We compared straight and curved reinforced endotracheal tubes in terms of intubation success rate, delay of intubation, incidence of impingement with the arytenoids, and postoperative sore throat and hoarseness. After obtaining approval from the Research Ethics Committee of Wakayama Medical University and written informed patient consent, 55 patients (45–84 yr) American Society of Anesthesiologists’ physical status I–III undergoing lumbar spine surgery had their tracheal intubation performed with an AWS using a tube size 7.5 for females (F) and 8.0 for males (M). Patients were assigned to the curved group (curved reinforced tube; Covidien, Mansfield, MA, USA), n = 25, M/F = 14/11, or to the straight group (straight reinforced tube; Fuji Systems Co., Bunkyo-ku, Tokyo, Japan), n = 30, M/F = 14/16. If intubation did not succeed at the first attempt, another insertion was allowed by adjusting the AWS direction upward. Twenty-four hours after surgery, severity of sore throat and hoarseness were graded. Sample size calculation was performed using the time from laryngeal view to intubation as the primary end point. Twenty-five patients were needed for an 89% power to detect changes of 4.8 sec at a significance level of 0.05; standard deviation (SD) = 5.2. Statistical analysis was performed using the Mann–Whitney U test or the v test. Patients in both groups had similar characteristics, including sex ratio, age, body mass index, Mallampati score, and duration of anesthesia. The intubation success rate was greater in the curved group than in the straight group (100% vs 83.3%, respectively; P 0.05). When failure of tracheal intubation occurred in the straight group, it was due to the arytenoid cartilages interfering with the tube advancement and not due to an inadequate view of the larynx. The time from laryngeal view to intubation lasted longer in the straight group than in the curved group (11.1 ± 5.2 sec vs 6.3 ± 4.7 sec, respectively; mean ± SD; P 0.05), whereas the time until the glottic view did not differ between groups (10.2 ± 7.0 sec vs 9.8 ± 5.9 sec, respectively). These results suggest that intubation delay in the straight group was not due to the inadequate laryngeal view. The number of insertion attempts was greater in the straight group than in the curved group (2.4 ± 1.4 attempts vs 1.2 ± 0.5 attempts, respectively; P 0.05), reflecting the need for more upward adjustments of the introducer tip T. Minonishi, MD H. Kinoshita, MD, PhD (&) K. Tange, MD Y. Hatano, MD, PhD Wakayama Medical University, Wakayama, Japan e-mail: hkinoshi@nike.eonet.ne.jp; hkinoshi@wakayama-med.ac.jp

Randomised comparison of Pentax AirwayScope and Glidescope for tracheal intubation in patients with normal airway anatomy

We compared intubating characteristics of the Pentax AirwayScope and Glidescope in a randomised controlled trial involving 140 patients. We found significantly shorter intubation times with mean (SD) 21.3 (12.3) vs 30.2 (13.2) s, lower intubating difficulty scores 4.4 (10.4) vs 12.8 (16.3) p < 0.001, and better grade 1 laryngeal views with the Pentax AirwayScope (95.7 vs 81.4%, p = 0.015). Significantly more optimisation manoeuvres were needed to successfully intubate with the Glidescope, with significant inability to align the tip of the tracheal tube with the glottic opening with the Glidescope in 9 (13%) vs no patients, p = 0.013. There was more mucosal bleeding (4 (5.7%) vs 1 (1.4%), p = 0.366), more lip bleeding (3 (4.3%) vs 1 (1.4%), p = 0.620) and significantly more postoperative sorethroat, 13 (18.6%) vs 0, p < 0.001 associated with the Glidescope.

The Diagnostic Value of the Upper Lip Bite Test Combined with Sternomental Distance, Thyromental Distance, and Interincisor Distance for Prediction of Easy Laryngoscopy and Intubation: A Prospective Study

Accuracy of upper lip bite test (ULBT) has been compared with the Mallampati classification. In this study, we investigated whether the combination of the ULBT classification with sternomental distance (SMD), thyromental distance (TMD), and interincisor distance (IID) or a composite score can improve the ability to predict easy laryngoscopy and intubation compared with each test alone. In a prospective study, 380 patients who were scheduled for elective surgery were selected randomly and enrolled in the study. Before inducing anesthesia, the airways were assessed, and ULBT class, SMD, TMD, and IID determined. Laryngoscopic view according to the Cormack and Lehane grading system was determined after induction of anesthesia and Grades 3 and 4 defined as "difficult intubation." By using receiver operating characteristic analysis, the best cutoff points of the tests were calculated. Finally, sensitivity, specificity, positive and negative predictive values and accuracy of these tests and their combinations with the ULBT were calculated. The prevalence of difficult intubation was 5% (n = 19). Class III ULBT, IID <4.5 cm, TMD <6.5 cm, and SMD <13 cm were defined as predictors of difficult intubation. There was no significant difference regarding difficult intubation based on gender (P < 0.05), whereas there were significant differences between the older tests and laryngeal view (P < 0.05, Mc-Nemar test). Specificity and accuracy of the ULBT were significantly higher than TMD, SMD, and IID individually (specificity was 91.69%, 82.27%, 70.64%, and 82.27%, respectively, and accuracy was 91.05%, 71.32%, 81.84%, and 76.58%, respectively). The combination of the ULBT with SMD provided the highest sensitivity. We conclude that the specificity and accuracy of the ULBT is significantly higher than the other tests and is more accurate in airway assessment. However, the ULBT in conjunction with the other tests could more reliably predict easy laryngoscopy or intubation.