Berry C B, Butler P J, Myles P S
Department of Anaesthesia, Alfred Hospital, Prahran, Victoria, Australia.
Br J Anaesth. 1993 Dec;71(6):864-8. doi: 10.1093/bja/71.6.864.
It is not clear if the use of continuous positive airway pressure (CPAP) during cardiopulmonary bypass (CPB) improves lung function after cardiac surgery. We have measured alveolar-arterial oxygen partial pressure difference (PAO2-PaO2) in 61 patients undergoing elective coronary artery bypass surgery. We studied three groups of patients: in group 1 the lungs were disconnected from the breathing system (no CPAP) during CPB; in group 2, 5 cm H2O CPAP with air was applied to the lungs; in group 3, 5 cm H2O of CPAP was applied with 100% oxygen. (PAO2-PaO2) was measured before CPB and then at 30 min, 4 h and 8 h after CPB. Compared with group 1 (no CPAP), (PAO2-PaO2) was significantly smaller in groups 2 and 3 at 30 min (P = 0.036), but not at 4 h and 8 h after CPB (P = 0.32, P = 0.96). The time to extubation (P = 0.42) and early extubation (P = 0.87) were not affected by the use of CPAP. The results of this study do not support the use of CPAP during CPB as a mechanism of improving lung function after cardiac surgery.
目前尚不清楚在体外循环（CPB）期间使用持续气道正压通气（CPAP）是否能改善心脏手术后的肺功能。我们测量了61例行择期冠状动脉搭桥手术患者的肺泡-动脉血氧分压差（PAO2-PaO2）。我们研究了三组患者：第1组在CPB期间肺与呼吸系统断开连接（无CPAP）；第2组，对肺施加5 cm H2O的空气CPAP；第3组，对肺施加5 cm H2O的100%氧气CPAP。在CPB前以及CPB后30分钟、4小时和8小时测量（PAO2-PaO2）。与第1组（无CPAP）相比，第2组和第3组在30分钟时（PAO2-PaO2）显著更小（P = 0.036），但在CPB后4小时和8小时时并非如此（P = 0.32，P = 0.96）。拔管时间（P = 0.42）和早期拔管情况（P = 0.87）不受CPAP使用的影响。本研究结果不支持在CPB期间使用CPAP作为改善心脏手术后肺功能的一种机制。
