Mucosal pressures from the cuffed oropharyngeal airway vs the laryngeal mask airway

Abstract

We tested the hypothesis that pressures exerted on the pharyngeal mucosa by the laryngeal mask airway (LMA) and cuffed oropharyngeal airway (COPA) differ, in 20 male and 20 female adult patients. Microchip pressure sensors were attached to the LMA and COPA at four similar anatomical locations (base of the tongue, lateral pharynx, posterior pharynx and distal oropharynx) and two dissimilar locations (LMA, piriform fossa and hypopharynx; COPA, middle of the tongue and proximal oropharynx). Cuff volume was adjusted until oropharyngeal leak pressure (OLP) was 10 cm H2O and mucosal pressures were recorded. This was repeated at an OLP of 15 cm H2O and at maximal OLP. Overall mucosal pressures were higher for the COPA than the LMA at 10 cm H2O (17 vs 3 cm H2O; P < 0.0001), at 15 cm H2O (21 vs 6 cm H2O; P < 0.0001) and at maximal OLP (26 vs 9 cm H2O; P < 0.0001). Mucosal pressures were always higher for the COPA at the base of the tongue, posterior pharynx and lateral pharynx, but were similar in the distal oropharynx. Maximal OLP was higher for the LMA than the COPA (27 (95% confidence intervals 25-29) vs 16 (12-19) cm H2O; P < 0.0001). We conclude that pressures acting on the mucosa were higher with the COPA compared with the LMA.