ProSeal versus the classic laryngeal mask airway for positive pressure ventilation during laparoscopic cholecystectomy

Background. We tested the hypothesis that the ProSeal laryngeal mask airway (PLMA) is a more effective ventilatory device than the Classic laryngeal mask airway (LMA‡) for laparoscopic cholecystectomy. Methods. Eighty anaesthetized, paralysed patients (ASA 1-2, aged 18-80 yr) were randomly allocated for airway management with the PLMA or LMA. Ease of insertion and efficacy of seal were determined. Peak airway pressures were recorded immediately before and after carboperitoneum to 2.0 kPa. The inspired oxygen concentration and/or the ventilatory variable were adjusted according to a protocol to maintain Sp_O2 ≥95% and E' _CO2 <6.0 kPa. Oxygenation was considered suboptimal if Sp_O2 fell to 94-90% and failed if Sp_O2 was <90%. Ventilation was considered suboptimal if E' _CO2 was >6.0-7.3 kPa and failed if E' _CO2 was >7.3 kPa. Results. First-time insertion success rates were higher for the LMA (40/40 vs 33/40; P=0.02). Seven patients required two attempts with the PLMA. Oropharyngeal leak pressure was higher for the PLMA [29 (SD 6) vs 19 (4) cm H₂O; P<0.001]. There was a similar, significant increase in peak airway pressure after carboperitoneum for both devices (P<0.001). Before carboperitoneum, oxygenation and ventilation were optimal in all patients in both groups. After carboperitoneum, oxygenation was optimal in all patients in both groups, but ventilation was suboptimal more frequently with the LMA (8 vs 0; P=0.01). In three of these eight patients, ventilation failed but was subsequently optimal with the PLMA. Conclusion. The PLMA is a more effective ventilatory device for laparoscopic cholecystectomy than the LMA. We do not recommend the use of the LMA for laparoscopic cholecystectomy.