Difficult Laryngoscopy Experienced by In-training Anesthesiologists in Apparently Normal Indian Surgical Population. How Much Does Optimal External Laryngeal Manipulation Help?

Background: The incidence of difficult laryngoscopy among in-training anesthesiologists remains unclear. In addition, the effectiveness of optimal external laryngeal manipulation (OELM) in enhancing the laryngoscopic view during elective intubations by these trainees has not been assessed. Aim: This study aimed to determine the incidence of difficult laryngoscopy, defined by the Cormack–Lehane grading system, and to evaluate the impact of OELM on the laryngoscopic view. Furthermore, the diagnostic accuracy of five difficult airway predictors (upper lip bite test, Mallampati classification, atlanto-occipital extension, thyromental distance, and interincisor gap) was examined. Methodology: This prospective observational study was conducted at a 1000-bed tertiary care hospital. Patients undergoing general anesthesia were included, except those requiring nasal intubation, laryngeal mask airways, ASA grades III–IV, faciomaxillary trauma, airway tumors, or emergency intubation. Operators were anesthesiologists with at least six months of training and 100 intubations. Preoperative airway assessments included the upper lip bite test (ULBT), Mallampati score, atlanto-occipital extension, thyromental distance, and interincisor gap. Laryngoscopy was performed after induction with thiopentone and vecuronium, with ventilation confirmed. The laryngeal view was graded per Cormack–Lehane criteria. Optimal external laryngeal manipulation (OELM) was applied if needed. A senior anesthesiologist supervised all procedures. With an estimated difficult laryngoscopy prevalence of 18%, the required sample was 1750; 1914 patients were included. Ethics approval was obtained, and the study was registered (CTRI/2016/01/006510). Statistical analysis was conducted using SPSS v17 and WINPEPI v11. Results: Of 1914 laryngoscopic attempts, 18.7% were difficult (grades 3 and 4). OELM significantly reduced the incidence of difficult views to 4.44% (P < 0.001), with no failed intubations. The study concluded that in-training anesthesiologists encounter difficult laryngoscopic views in about one in five cases. However, the five airway predictors studied showed limited effectiveness as screening tools for difficult laryngoscopy, while OELM proved to be a valuable technique for improving laryngoscopic views during elective intubations. Conclusions: Almost one in five laryngoscopic views encountered by in-training anesthesiologists is difficult (Cormack–Lehane grade 3 or 4). The five different airway predictors studied found that these tests were poor for screening predicting difficult laryngoscopy. OELM is a “handy” technique to improve difficult laryngoscopic view during elective intubations.