Comparison of the oropharyngeal leak pressure in head rotation between a first-generation laryngeal mask and the i-gel laryngeal mask during general anesthesia - a randomized controlled trial.

BACKGROUND

The laryngeal mask airway (LMA) is essential in anesthesia, using an air-inflatable cuff for optimal pharyngeal fit. The i-gel® LMA (i-gel) is unique for its thermoplastic elastomer material making an air-inflatable cuff unnecessary and has shown higher oropharyngeal leak pressure (OLP) than first-generation LMA (cLMA) in neutral head position, however, mixed results for head rotation. This prospective study aimed to compare OLP between the cLMA and i-gel during head rotation.

METHODS

Patients undergoing elective surgery securing the airway with either cLMA or i-gel were included. Exclusion criteria included a Body Mass Index > 30 kg/m², cervical spine pathologies or restricted head rotation. OLP was measured after induction at 60° bilateral head rotation for primary outcome. Secondary outcomes were OLP at 0° head rotation and postoperative complications on postoperative day 1.

RESULTS

116 patients were randomized to either the cLMA (n = 60) or i-gel (n = 56) group. No significant difference was found in the OLP with 60° head rotation to the left (cLMA 20 cmH2O [Interquartile range [IQR] 18-22], i-gel 21 cmH2O [IQR 18-22.75], P = 0.752) and the right (cLMA 20 cmH2O [IQR 18-22], i-gel 20 cmH2O [IQR 15-21], P = 0.324). OLP was also comparable in a neutral head position (P = 0.368). No significant differences in postoperative outcome were observed.

CONCLUSIONS

This study demonstrated comparable OLP between cLMA and i-gel during head rotation. This indicates equivalent efficacy and seal integrity of both LMAs during head rotation, resulting in sufficient tidal volumes during rotated head positions.

TRIAL REGISTRATION: German Clinical Trials Register, retrospectively registered under DRKS00031785 (date of registration 26.04.2023).