It is known that pneumoperitoneum and changes of body position during laparoscopic surgery influenced peak inspiratory pressure (PIP). We asked the question whether oropharyngeal leak pressure (OLP) is changed by changes in intraabdominal pressure and position during laparoscopic surgery with a ProSeal laryngeal mask airway (PLMA). Since gynecological laparoscopic surgery (Lap-Gy) and laparoscopic cholecystectomy (Lap-C) require different surgical positions, we included both surgeries in this study so that we could investigate the effects of various positions on OLP.

Lap-Gy (n = 15) was performed in the trendelenburg position combined with the lithotomy position, whereas Lap-C (n = 10) was performed in the reverse trendelenburg position. The measured variables were PIP and OLP. We also marked the fiberoptic score to determine the intraoral position (FP) of the PLMA. OLP was measured using a manometric stability test. The variables were measured in a regular sequence as follows: S-0°-0, L-0°-0, L-0°-15, L-(-15°)-15, L-(-30°)-15 in Lap-Gy and S-0°-0, S-0°-15, S-(+15°)-15, S-(+30°)-15 in Lap-C. At each measured point, the capital S means supine and L lithotomy. Intermediate numbers with a '°' superscript are table angles to the horizontal plane (degrees) , '-' means the trendelenburg position and '+', the reverse trendelenburg position, and the last number represents intraabdominal pressure (mmHg).

PIP was significantly increased when L-0°-0 changed to L-0°-15, L-0°-15 to L-(-15°)-15 and L-(-15°)-15 to L-(-30°)-15 in Lap-G, and when S-0°-0 was changed to S-0°-15 in Lap-C (P < 0.05). But, OLP and FP were not significantly altered by changes in postion or intraabdominal pressure in both Lap-Gy and Lap-C.

PIP was affected by pneumoperitoneum and positional changes. But, increases in intraabdominal pressure by pneumoperitoneum and changes in position during laparoscopic surgery had no effect on OLP and FP of PLMA.