CPAP at 10 cm H(2)O during cardiopulmonary bypass does not improve postoperative gas exchange

Objective: To compare postoperative (PO) pulmonary gas exchange indexes in patients submitted to myocardial revascularization (MR) with or without the application of continuous positive airway pressure (CPAP) during cardiopulmonary bypass (CPB). Methods: Thirty adult patients submitted to MR with CPB between March and September 2005 were randomly allocated to two groups: CPAP (n=15), patients that received CPAP at 10 cmH(2)O during CPB, and control (n=15), patients that didn't receive CPAP. PaO(2)/FiO(2) and P(A-a)O(2) were analyzed at four moments: Pre dust before CPB, with FiO(2)=1.0); Post (30min post-CPB, with FiO(2)=1.0); immediate PO period (12h post-surgery, with FiO(2)=6.4 by using a Venturi (R) facial mask) and first PO day (24h post-surgery, with FiO(2)=0.5 by a facial mask). Results: PaO(2)/FiO(2) and P(A-a)O(2) tend to get significantly worst as time elapsed during the postoperative period in both groups, but no differences were observed between them at any moment. When PaO(2)/FiO(2) was subdivided into three categories, a greater prevalence of patients with values between 200 mmHg and 300mmHg were observed in CPAP group only at moment Post (30min post-CPB; p = 0.02). Conclusion: CPAP at 10cmH2O administered during CPB, although had lightly improved PaO(2)/FiO(2) at 30 minutes post-CPB, had no significant sustained effect on postoperative pulmonary gas exchange. We concluded that in patients submitted to MR, application of 10 cmH(2)O CPAP does not improve postoperative pulmonary gas exchange.23220921