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 (PA(O2) - Pa(O2)) 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. (PA(O2) - Pa(O2)) was measured before CPB and then at 30 min, 4 h and 8 h after CPB. Compared with group 1 (no CPAP), (PA(O2) - Pa(O2)) 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.
|Number of pages||5|
|Journal||British Journal of Anaesthesia|
|Publication status||Published - 1993|
- Cardiovascular surgery
- Gas exchange