AUTOTRANSFUSION - IS THERE A BENEFIT IN A CURRENT PRACTICE OF AGGRESSIVE BLOOD CONSERVATION

Findings from early studies suggested that the autotransfusion of shed mediastinal blood (ATS) after cardiac surgical procedures led to a reduction in the postoperative banked blood requirements. However, changes in baseline patient characteristics and other blood conservation methods may now negate the benefits of ATS. To determine whether the routine use of ATS is effective in the context of current surgical practice, risk factors related to postoperative banked blood requirements were analyzed in a prospective series of 155 consecutive patients undergoing cardiac operations: 71 patients before and 84 patients after the addition of ATS to an already aggressive standardized blood conservation protocol. The overall mean patient age was 66 +/- 11 years; the mean preoperative patient hemoglobin level was 11.8 +/- 1.8 g/dL; 48% of the procedures were elective and 12% were reoperations; coronary artery bypass grafting was performed in 73% of the patients and valve repair or replacement in 34%, with no differences between the non-ATS and ATS groups (all, p = not significant). The mean 24-hour postoperative blood loss was 1,278 +/- 814 mL in the non-ATS group and 1,721 +/- 1,510 mt in the ATS group (p < 0.03). The mean volume autotransfused in the ATS group was 1,122 +/- 97 mL. The overall reoperation rate for bleeding was 0.6% (70% confidence interval, 0 to 1.3%) and the hospital mortality was 1.9% (70% confidence interval, 0.8% to 3.1%), which did not differ between the non-ATS and ATS groups (both, p = not significant). In the non-ATS group, 56% of the patients required postoperative banked blood, compared with only 39% in the ATS group (p < 0.05). In the subgroup of patients undergoing isolated coronary artery bypass grafting, 71% (27/38) of the non-ATS patients required banked blood, compared with only 34% (19/56) of the ATS patients (p < 0.001). The mean hemoglobin values in the patients at hospital discharge were similar in the two groups (non-ATS, 10.8 +/- 1.3 g/dL; ATS, 10.2 +/- 1.1 g/dL; p = not significant). By multivariate analysis, identified risk factors for postoperative banked blood requirement were advanced preoperative angina class and heart failure class, smaller body surface area, and greater postoperative blood loss (all, p < 0.01). Controlling for these factors, nonuse of ATS was an additional significant incremental risk factor for banked blood requirement (p < 0.01; relative risk, 1.3; 95% confidence interval, 1.1 to 1.4). These data demonstrate the addition of routine ATS to a current practice of aggressive blood conservation confers a substantial reduction in the requirement for postoperative banked blood across the spectrum of patients undergoing cardiac surgical procedures.