A Comparison of Four Methods for Assessing Oropharyngeal Leak Pressure with the Laryngeal Mask Airway (LMA) in Paediatric Patients

Background: This study compares four tests for assessing oropharyngeal leak pressure with the laryngeal mask airway (LMA). We tested the hypothesis that the oropharyngeal leak pressure and interobserver reliability differs between tests.

Methods: Eighty paralysed anaesthetized paediatric patients (weight 10-30 kg) were studied with the intracuff pressure set at 60 cmH2O. Four different oropharyngeal leak pressure tests were performed in random order on each patient by two observers blinded to each other's measurements. Test 1 involved detection of an audible noise. Test 2 involved detection of endtidal CO2 in the oral cavity. Test 3 involved observation of the aneroid manometer dial as the pressure increased and noting the airway pressure at which the dial reaches stability. Test 4 involved detection of an audible noise by neck stethoscopy.

Results: The mean oropharyngeal leak pressure was 12.5 cmH2O and was similar between tests. The intraclass correlation coefficient was 0.99 for all tests and was classed as excellent.

Conclusions: We conclude that all four tests provide accurate and reliable information about oropharyngeal leak pressure in children.