Comparison of laryngeal exposure in bed-up-head-elevated Macintosh laryngoscopy vs. supine C-MAC video laryngoscopy: a randomized non-inferiority trial.

Background: Tracheal intubation can be challenging, especially in unanticipated cases, where patient positioning plays a critical role. The bed-up-head-elevated (BUHE) position may improve intubation outcomes.

Research design and methods: This randomized non-inferiority trial included 90 ASA I-II patients undergoing elective surgery. Patients were randomly allocated into two groups. Group 1 underwent Macintosh laryngoscopy in the BUHE position followed by C-MAC laryngoscopy in the supine position, while Group 2 followed the reverse order. Endotracheal intubation was attempted with the second blade used for laryngoscopy. Laryngeal exposure was evaluated using Percentage of Glottic Opening (POGO) scores and Cormack - Lehane (CL) grading with a non-inferiority margin of -15% for POGO scores. Secondary outcomes included time required for intubation, attempts, adjuncts, effort, and complications.

Results: BUHE Macintosh laryngoscopy yielded a mean POGO score of 50.5% compared to 63.4% with supine C-MAC laryngoscopy, with a mean difference of -12.9% (95% CI: -16.6% to -9.3%). CL grading favored C-MAC, while secondary outcomes showed no significant differences.

Conclusion: BUHE Macintosh laryngoscopy resulted in lower laryngeal exposure, as the confidence interval crossed the non-inferiority margin. However, secondary outcomes remained comparable. Further studies are required to validate these findings and refine non-inferiority margins.

Trial registration-: CTRI/2023/02/050036.