Quality assessment of intraoperative blood salvage and autotransfusion

Intraoperative blood salvage and autotransfusion are commonly used to minimize exposure to banked blood. Although this technique has been used widely for years, data vary regarding the quality of autotransfused blood. Salvaged blood may contain plasma, residual heparin, and free hemoglobin released from damaged cells. All of these factors may contribute to the adverse sequelae sometimes seen with autotransfusion. For these reasons, we have monitored autotransfused blood to assess its quality. Intraoperative blood salvage was used during most cardiac procedures and at the discretion of the surgeon in other specialties. Blood was collected through a double lumen catheter that was anticoagulated with heparin, filtered, centrifuged, and washed with saline. A sample of the blood was removed for analysis, which included hematocrit, heparin assay, fibrinogen, and free hemoglobin levels. Over a 6-year period, 1593 patients had intraoperative blood salvage with quality assessment. The majority of patients underwent cardiac operations (941 patients, 59%), whereas 243 had orthopedic (15%) and 208 had vascular (13%) procedures. Additionally, there were 127 pediatric patients (8%) and 74 miscellaneous procedures (5%). The highest average yield of salvaged blood was during vascular procedures (1073 +/- 76 mL), whereas orthopedic cases had the lowest yield (378 +/- 19 mL) and hematocrit (39%). There was minimal residual heparin activity, even in patients requiring systemic anticoagulation (0.3 to 0.5 units/mL). Patients undergoing pediatric procedures had the lowest concentration of free hemoglobin (476 mg/L), whereas all adult patients had higher free hemoglobin levels, especially vascular operations (990 mg/L). Intraoperative salvaged blood has minimal heparin activity, even in procedures requiring systemic anticoagulation. Fibrinogen, a marker of residual plasma, was undetectable in the majority of cases. These data indicate that intraoperative blood salvage generally results in a high-quality product (good hematocrit, low heparin, minimal plasma), although there are significant differences in free hemoglobin levels depending on the operative procedure.