Is the Bain breathing circuit the future anesthesia system? An evaluation.

The Bain breathing circuit, a modified Mapleson D system, was evaluated with regard to oxygenation and CO2 elimination under controlled conditions and compared with the presently popular semiclosed breathing circuit (SCBC) with CO2 absorber. The authors demonstrated that the Bain system compares favorably with the SCBC in regard to oxygenation of manually ventilated patients with fresh gas inflow of 70 ml/kg/min while maintaining a PaCO2 at a mean of 38 torr versus an SCBC mean of 32 torr. The authors were impressed with the clinical simplicity, efficiency, and versatility of the Bain system and believe that it will play a major role in the future of anesthesia-machine design.