Does the ProSeal laryngeal mask airway prevent aspiration of regurgitated fluid?

In this randomized, cross-over cadaver study, we determined whether a new a irway device, the ProSeal laryngeal mask airway (PLMA; Laryngeal Mask Compa ny, Henley-on-Thames, UK), prevents aspiration of regurgitated fluid. We st udied five male and five female cadavers (6-24 h postmortem). The infusion set of a pressure/controlled, continuous flow pump was inserted into the up per esophagus and ligated into place. Esophageal pressure (EP) was increase d in 2-cm H2O increments. This was performed without an airway device (cont rol) and over a range of cuff volumes (0-40 mL) for the classic laryngeal m ask airway (LMA), the PLMA with the drainage tube clamped (PLMA clamped) an d unclamped (PLMA unclamped). The EP at which fluid was first seen with a f iberoptic scope in the hypopharynx (control), above or below the cuff, or i n the drainage tube, was noted. Mean EP at which fluid was seen without any airway device was 9 (range 8-10) cm H2O. EP at which fluid was seen was al ways higher for the PLMA clamped and LMA compared with the control tall, P < 0.0001). The mean EP at which fluid was seen for the PLMA unclamped was s imilar to the control at 10 (range 8-13) cm H2O. For the PLMA unclamped, fl uid appeared from the drainage tube in all cadavers at 10-40 mt cuff volume and in 8 of 10 cadavers at zero cuff volume. Mean EP at which fluid was se en above the cuff was similar for the PLMA clamped and LMA at 0-30 mt cuff volume, but was higher for PLMA clamped at 40-mL cuff volume (81 vs 48 cm H 2O, P = 0.006). Mean EP at which fluid was seen below the cuff was similar at 0-10 mt cuff volume, but was higher for the PLMA clamped at 20, 30, and 40 mt cuff volume (62, 68, 73 vs 46, 46, 46 cm H2O, respectively, P < 0.04) . For the PLMA clamped and the LMA, fluid appeared simultaneously above and below the cuff at all cuff volumes. We concluded that in the cadaver model , the correctly placed PLMA allows fluid in the esophagus to bypass the pha rynx and mouth when the drainage tube is open. Both the LMA, and PLMA with a closed drainage tube, attenuate Liquid flow between the esophagus and pha rynx. This may have implications for airway protection in unconscious patie nts.