Autotransfusion after cardiac operation: Assessment of hemostatic factors

Reinfusion of mediastinal blood after coronary bypass grafting reduces the need for homologous transfusion with its hazards. To determine the efficacy of autotransfusion using the cardiotomy reservoir used during operation as a postoperative collection system, we studied the characteristics of reservoir blood (minimum 500 ml, mean 810 ml) and compared the hematologic profiles of 21 patients before and after blood infusion. The mean hematocrit value of the shed blood was 25% ± 7%, platelet count 60,000 ± 39,000/μml, fibrinogen 19 ± 25 mg/dl, and factor VIII 11% ± 7%. The fibrinopeptide A concentration was 400 ng/ml, and the Bβ 15-42 peptide was 28 ± 14 pmol/ml. These values indicate defibrination of the blood before collection (no clots were found in the reservoirs), and no significant differences were detected between the types of reservoirs used (Bently, n = 10, Shiley, n = 11). Infusion of reservoir blood between 500 and 1860 ml did not significantly affect the factor VIII, fibrinopeptide A, or Bβ 15-42 peptide levels. Fibrinogen levels increased from 254 to 395 mg/dl (p < 0.001). Only six of 21 patients received bank blood before discharge. These findings indicate that extensive coagulation occurs within the mediastinum before the blood is collected, that mediastinal blood can be safely infused without inducing fibrinolysis or disseminated intravascular coagulation, and that use of the cardiotomy reservoir is a safe and inexpensive method of autotransfusion after coronary artery bypass grafting.