[Initial clinical experience with cardiopulmonary bypass and auto-oxygenation]

Cardiopulmonary bypass has been successfully used in cardiac surgery for more than 39 years. In spite of many technical improvements oxygenators are still damaging to blood. We therefore decided to change the conventional CPB into biventricular bypass without an oxygenator, using the patient's lungs for autooxygenation. A double-pump system without an oxygenator was used in 11 patients undergoing aortocoronary bypass grafting. The cardiopulmonary pulmonary setup consisted of two separate systems with two roller pumps, plastic reservoirs and filters, and one cardiotomy reservoir and heat exchanger. Cannulations were performed through the right atrium and pulmonary artery for right-sided bypass, and through the left atrium and aorta for left-sided bypass. The results confirmed the full reliability of autooxygenation during CPB. All patients were well oxygenated with and inspired oxygen fraction of 30%. Values of arterial and venous O2 saturation as well as pO2 and pCO2 varied within the normal range. Platelet count decreased by 23% between interval I and IV, but only by 12% during biventricular bypass. Fibrinogen concentration decreased by 7% between interval I and IV, but only by 4% during biventricular bypass. No patient developed postperfusion syndrome. In our small series of patients, biventricular bypass was found to be simple to handle and to provide good conditions for the surgical procedure. It appears to be more physiological and less traumatic than conventional CPB. The described approach may further improve results of aortocoronary bypass grafting. (Tab. 2, Fig. 1, Ref. 12.).