Successful direct laryngoscopy and endotracheal intubation depend on proper head and neck positioning, airway anatomy, and cervical spine mobility. Optimal positioning improves glottic visualization and intubation ease, but the ideal head elevation required remains unclear. Traditional bedside airway assessment methods are subjective and may not reliably predict difficulty.This randomized controlled study was conducted to evaluate the effect of different pillow heights used for head and neck positioning on airway geometry and intubation characteristics. The study also assessed ultrasound guided hyomental distance and hyomental distance ratio as objective predictors of airway extensibility and ease of laryngoscopy.Adult patients undergoing elective surgery under general anesthesia were randomly allocated into two groups. Ultrasound measurements were obtained in neutral and extended positions before induction. Direct laryngoscopy was performed and laryngoscopic view and intubation difficulty were recorded. Intubation time, number of attempts, and hemodynamic responses were also noted. Results showed that the group with 9 cm pillow height demonstrated greater hyomental distance, better airway extension, improved vocal cord visualization, and shorter intubation time compared to the other group. Hemodynamic responses were comparable between groups.

The study suggests that optimal head and neck positioning improves airway geometry and facilitates easier intubation. Ultrasound guided hyomental distance ratio may serve as an objective tool in preoperative airway assessment.