Correlation Between Bedside Anatomical Indicators and Lifting Force and Glottic Exposure Under Different Video Laryngoscopy Techniques

This single-center prospective observational study plans to enroll 196 patients undergoing elective general anesthesia. The study aims to investigate the correlation between preoperative bedside anatomical indicators (including modified Mallampati classification, upper lip bite test, mouth opening, head circumference, and thyromental distance) and the peak lifting force applied during video laryngoscopy, as well as the degree of glottic exposure (POGO score). The study will also evaluate the potential benefit of the direct epiglottis elevation technique in specific anatomical subgroups. After anesthesia induction, the same anesthesiologist will perform video laryngoscopy using two distinct techniques in a fixed sequence: the indirect (vallecula) method and the direct (subepiglottic) method. Peak lifting force will be quantitatively measured in real-time using a resistive thin-film pressure sensor attached to the laryngoscope blade. The primary outcomes are the POGO scores and peak lifting forces under both techniques. The secondary outcome includes the change in POGO score (ΔPOGO) between techniques. The study will provide quantitative evidence regarding the "anatomy-force-view" relationship and aid in individualized clinical decision-making for video laryngoscopy intubation.