Randomized crossover comparison between the i-gel and the LMA-Unique in anaesthetized, paralysed adults

Abstract

Background: The i-gel differs from other supraglottic airway devices, in that it has a softer, non-inflatable cuff. This study was designed to compare the performance of the i-gel and the LMA-Unique (LMA-U) when used during anaesthesia in paralysed patients.

Methods: Both devices were studied in 39 anaesthetized, paralysed patients in a randomized crossover trial. The primary outcome was airway leak pressure. Secondary outcomes included time to insertion, the number of insertion and reposition attempts, leak volumes, and leak fractions.

Results: There was no significant difference between the airway leak pressures of the two devices [median (IQR) leak pressures 25 (22-30) vs 22 (20-28) cm H(2)O for the i-gel and LMA-U, respectively; P=0.083, 95% CI of the mean difference -0.32 to 4.88 cm H(2)O]. The median (IQR) insertion time for the i-gel was significantly less than for the LMA-U [12.2 (9.7-14.3) vs 15.2 (13.2-17.3) s; P=0.007]. All the LMA-U devices and 38 of 39 i-gel airways were inserted at the first attempt. The number of manipulations required after insertion to achieve a clear airway was the same in both the groups (four in each). There were no statistically significant differences in leak volumes or leak fractions during controlled ventilation.

Conclusions: We found no difference in leak pressures and success rate of first-time insertion between the i-gel and the LMA-U. Time to successful insertion was significantly shorter for the i-gel. We conclude that the i-gel provides a reasonable alternative to the LMA-U for controlled ventilation during anaesthesia.