Cardiac surgery with cardiopulmonary bypass is associated with a systemic inflammatory response syndrome. The major clinical features of this include a reduction of pulmonary compliance and increased extracellular fluids, with increased pulmonary shunt fraction similar to acute respiratory distress syndrome, thus resulting in prolonged mechanical ventilation time (VAM) and intensive care unit length of stay (ICU STAY). We evaluated the feasibility of an intraoperatory cardiopulmonary bypass (CPB) circuit connected with a monitor for continuous veno-venous hemofiltration (CVVH) to ameliorate pulmonary function after open heart surgery reducing VAM and ICU STAY. Forty patients undergoing elective coronary artery bypass grafting were randomized at the time of surgery into a control group (20 patients who received standard cardiopulmonary bypass) and a study group (20 patients who received CVVH during cardiopulmonary bypass). The analysis of postoperative variables showed a significative reduction of VAM in treated group (CVVH group mean 3.55 h +/- 0.85, control group 5.8 h +/- 0.94, P < 0.001) and ICU STAY (CVVH group mean 29.5 h +/- 6.7, control group 40.5 h +/- 6.67, P < 0.001). In our experience, the use of intraoperatory CVVH during cardiopulmonary bypass is associated with lower early postoperative morbidity.