Comparison of three blood-processing techniques during and after cardiopulmonary bypass

The return of extracorporeal circuit blood at the termination of cardiopulmonary bypass is an important feature of blood conservation during open heart procedures. However, the relative benefits and disadvantages of different circuit blood salvage methods remain unclear. Accordingly, the purpose of this study was to examine whether quantifiable differences exist between three different circuit blood-salvaging techniques: direct infusion, centrifugation, and ultrafiltration. Sixty patients with very similar preoperative characteristics were randomly assigned to each of the three groups, and blood coagulation screens, plasma profiles, and respiratory function were determined at 20 minutes and at 6 and 18 hours after cardiopulmonary bypass. Early after cardiopulmonary bypass (20 minutes), the plasma colloid osmotic pressure and fibrinogen and platelet concentrations were significantly higher with ultrafiltration (p < 0.05) versus those observed for the other two methods. The plasma thromboplastin times were significantly (p < 0.05) longer after cardiopulmonary bypass with centrifugation as compared to direct infusion and ultrafiltration. However, the coagulation profiles and plasma composition normalized by 18 hours after cardiopulmonary bypass with all three blood-salvaging methods. There were no significant differences in terms of blood utilization or chest tube drainage over the entire postoperative period among any of the circuit blood-salvaging methods. These results suggest that ultrafiltration of postcardiopulmonary circuit blood may preserve plasma colloid pressure and platelet concentration in the early postoperative period, but these differences do not persist. Thus, for routine cardiopulmonary bypass procedures, direct infusion, centrifugation, and ultrafiltration may all be satisfactory methods of circuit blood salvage.