HEPARIN VERSUS CITRATE REGIONAL ANTICOAGULATION DURING AUTOTRANSFUSION IN A PORCINE INTRAABDOMINAL HEMORRHAGE MODEL

Our objective was to determine the effects of anticoagulants and blood loss on hemodynamic, hematologic, and coagulation parameters followin g autotransfusion in an animal model of intraabdominal hemorrhage. We performed a prospective, randomized observational animal study at an a nimal research laboratory at a university medical center. Eight Landra ce, domestic pigs, weighing 17-23 kg, each underwent jugular venous an d iliac arterial catheterization and laparotomy with retroperitoneal d issection for aortic exposure to simulate an operative environment. Fo llowing baseline laboratory and hemodynamic determinations, intra-abdo minal hemorrhage was accomplished via aortotomy in three sequential 10 mL/kg blood volumes. After allowing pooling in the exposed retroperit oneum to ensure tissue contact, the shed blood was suctioned, processe d, and washed in an autotransfusion device utilizing either heparin (n = 4) or acid-citrate-dextrose (n = 4) as a system anticoagulant. Prio r to autologous transfusion, each pig received a 20 mL/kg int-ravenous bolus of 0.9 per cent saline to treat shock. The processed blood was then infused, and laboratory and hemodynamic measurements were repeate d following each cycle of hemorrhage and autotransfusion. Sequential f ixed volume hemorrhage resulted in significant reductions in mean arte rial pressure. Despite crystalloid infusion and transfusion of process ed shed blood, postresuscitation mean arterial pressure did not return to baseline values, with no difference noted between anticoagulant gr oups. Infusion of increasing volumes of autologous blood resulted in s ignificant reductions in hematocrit, platelet count, fibrinogen, antit hrombin III, ionized calcium, and total protein. The decrease in conce ntration of each variable was independent of the choice of anticoagula nt with the exception of antithrombin III, with higher levels noted in animals receiving blood anticoagulated with acid-citrate-dextrose. Pr othrombin time and partial thromboplastin time were unaffected by volu me of autologous transfusion or choice of anticoagulant. We conclude t hat changes in hemodynamic, hematologic, and coagulation parameters as sociated with hemorrhage and autotransfusion appear related more to th e volume of blood loss and the cumulative pheresis of plasma than to t he choice of anticoagulant.