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

We tested the hypothesis that pressures exerted on the pharyngeal mucosa bythe laryngeal mask airway (LMA) and cuffed oropharyngeal airway (COPA)differ, in 20 male and 20 female adult patients. Microchip pressure sensorswere attached to the LMA and COPA at four similar anatomical locations(base of the tongue, lateral pharynx, posterior pharynx and distaloropharynx) and two dissimilar locations (LMA, piriform fossa andhypopharynx; COPA, middle of the tongue and proximal oropharynx). Cuffvolume was adjusted until oropharyngeal leak pressure (OLP) was 10 cm H2Oand mucosal pressures were recorded. This was repeated at an OLP of 15 cmH2O and at maximal OLP. Overall mucosal pressures were higher for the COPAthan the LMA at 10 cm H2O (17 vs 3 cm H2O; P < 0.0001), at 15 cm H2O (21vs 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 ofthe tongue, posterior pharynx and lateral pharynx, but were similar in thedistal 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). Weconclude that pressures acting on the mucosa were higher with the COPAcompared with the LMA.