Background:The incidence of difficult intubation in patients undergoing general anaesthesia is estimated to be approximately 1-18% whereas that of failure to intubate is 0.05-0.35%.1,2,3 Various methods have been used for prediction of difficult laryngoscopy. Although, upper lip bite has been shown to be a promising test in its introductory article, repeated validation in various populations is required for any test to be accepted as a routine test. We have compared upper lip bite test (ULBT), modified Mallampati test (MMC) and thyromental distance (TMD) individually and in various combinations to verify which of these predictor tests are significantly associated with difficult glottic exposure.Methods:After obtaining institutional ethics committee approval, 402 ASA I and II adult patients undergoing elective surgical procedures requiring endotracheal intubation were included. All the three test were performed in all the patients preoperatively and their glottic exposure was recorded by Cormack-Lehane classification during intubation. Sensitivity, specificity, positive predictive value and negative predictive value were used for comparison.Results:In our study, the incidence of difficult laryngoscopy was 11.4% and failure to intubate 0.49%. None of the three are a suitable predictive test when used alone. Combination of tests added incremental diagnostic value.Conclusion:We conclude that all three screening tests for difficult intubation have only poor to moderate discriminative power when used alone. Combinations of individual tests add some incremental diagnostic value.

Background and Aims:Desflurane and sevoflurane have low blood gas solubility co-efficients, allowing a rapid awakening from anaesthesia. However, desfluraneis pungent and may cause airway irritability. We compared desflurane and sevoflurane with respect to recovery and occurrence of adverse airway responses in spontaneously breathing patients while using the ProSeal™ laryngeal mask airway (LMA).Methods:Ninety-four adult patients undergoing hysteroscopic procedures were divided into sevoflurane (S) group or desflurane (D) group. Patients were premedicated with midazolam 0.03 mg/kg and fentanyl 1μg/kg. Anaesthesia was induced with propofol 2.0–2.5 mg/kg, followed by insertion of a ProSeal™ LMA. Adverse airway responses such as cough, hiccups, laryngospasm and breathholding were recorded. In the post-operative period: time to awakening, response to verbal commands, orientation, ability to sit with support and the recovery room Aldrete score were recorded.Results:Three patients in group S (6.4%) and six patients (13.3%) in Group D had adverse airway events. The mean time to eye opening (Group S-10.75 ± 7.54 min, Group D-4.94 ± 1.74 min), obeying verbal commands (Group S-13.13 ± 8.75 min, Group D-6.55 ± 1.75 min), orientation (Group S-15.42 ± 8.46 min, Group D-6.23 ± 2.4 min) and to sit with support (Group S-36.09 ± 12.68 min, Group D-14.35 ± 3.75 min) were found to be lesser with desflurane than with sevoflurane (P < 0.001). The mean time to recovery was delayed in Group S-46.00 ± 12.86 min compared to Group D-26.44 ± 5.33 min (P < 0.001).Conclusion:Desflurane has faster awakening properties than sevoflurane without an increase in adverse airway events when used during spontaneous ventilation through a ProSeal™ LMA along with propofol and fentanyl.

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