Comparison of 2 cuff inflation methods of laryngeal mask airway Classic for safe use without cuff manometer in adults

Purpose

This single-center, prospective, randomized, double-blind, 2-arm, parallel group comparison trial was performed to establish whether the adult-sized laryngeal mask airway (LMA) Classic (The Laryngeal Mask Company Ltd, Henley-on-Thames, UK) could be used safely without any consideration of cuff hyperinflation when a cuff of the LMA Classic was inflated using half the maximum inflation volume or the resting volume before insertion of device.

Basic procedures

Eighty patients aged 20 to 70 years scheduled for general anesthesia using the LMA Classic were included. Before insertion, the cuff was partially filled with half the maximum inflation volume in the half volume group or the resting volume created by opening the pilot balloon valve to equalize with atmospheric pressure in the resting volume group. Several parameters regarding insertion, intracuff pressure, airway leak pressure, and leakage volume/fraction were collected after LMA insertion.

Major findings

The LMA Classic with a partially inflated cuff was successfully inserted in all enrolled patients. Both groups had the same success rate of 95% at the first insertion attempt. The half volume group had a lower mean intracuff pressure compared with the resting volume group (54.5 ± 16.1 cm H₂O vs 61.8 ± 16.1 cm H₂O; P = .047). There was no difference in airway leak pressure or leakage volume/fraction between the 2 groups under mechanical ventilation.

Conclusions

The partially inflated cuff method using half the maximum recommended inflation volume or the resting volume is feasible with the adult-sized LMA Classic, resulting in a high success rate of insertion and adequate range of intracuff pressures.