Heparin versus citrate regional anticoagulation during autotransfusion in a porcine intra-abdominal hemorrhage model

Our objective was to determine the effects of anticoagulants and blood loss on hemodynamic, hematologic, and coagulation parameters following autotransfusion in an animal model of intraabdominal hemorrhage. We performed a prospective, randomized observational animal study at an animal research laboratory at a university medical center. Eight Landrace, domestic pigs, weighing 17-23 kg, each underwent jugular venous and iliac arterial catheterization and laparotomy with retroperitoneal dissection for aortic exposure to simulate an operative environment. Following baseline laboratory and hemodynamic determinations, intra-abdominal hemorrhage was accomplished via aortotomy in three sequential 10 mL/kg blood volumes. After allowing pooling in the exposed retroperitoneum to ensure tissue contact, the shed blood was suctioned, processed, and washed in an autotransfusion device utilizing either heparin (n = 4) or acid-citrate-dextrose (n = 4) as a system anticoagulant. Prior to autologous transfusion, each pig received a 20 mL/kg intravenous bolus of 0.9 per cent saline to treat shock. The processed blood was then infused, and laboratory and hemodynamic measurements were repeated following each cycle of hemorrhage and autotransfusion. Sequential fixed volume hemorrhage resulted in significant reductions in mean arterial pressure. Despite crystalloid infusion and transfusion of processed shed blood, postresuscitation mean arterial pressure did not return to baseline values, with no difference noted between anticoagulant groups. Infusion of increasing volumes of autologous blood resulted in significant reductions in hematocrit, platelet count, fibrinogen, antithrombin III, ionized calcium, and total protein. The decrease in concentration of each variable was independent of the choice of anticoagulant with the exception of antithrombin III, with higher levels noted in animals receiving blood anticoagulated with acid-citrate-dextrose. Prothrombin time and partial thromboplastin time were unaffected by volume of autologous transfusion or choice of anticoagulant. We conclude that changes in hemodynamic, hematologic, and coagulation parameters associated with hemorrhage and autotransfusion appear related more to the volume of blood loss and the cumulative pheresis of plasma than to the choice of anticoagulant.

Effects of free glycerol contained in intravenous fat emulsion on plasma triglyceride determination

BACKGROUND

Plasma triglyceride analyses to evaluate the clearance of IV fat emulsion are necessary in patients receiving parenteral nutrition. Enzymatic kits for triglyceride analysis measure the glycerol that is hydrolyzed from triglyceride. This study investigates the effect of fat emulsion free glycerol on plasma triglyceride determination.

METHODS

Venous blood from fasting volunteers (n = 10) was drawn into tubes containing EDTA and was centrifuged to separate the plasma. An IV fat emulsion containing 2.25% glycerol was added to plasma samples to create serial dilutions ranging from 0.049% to 0.245% final lipid concentration. Total triglyceride and free glycerol concentrations were determined in each dilution and control sample. The free glycerol concentration was subtracted from the total triglyceride concentration to yield a true triglyceride value.

RESULTS

Increasing concentrations of fat emulsion added to donor plasma produced increases in total triglyceride and free glycerol concentrations. The increase in free glycerol concentration produced significant concentration-related differences between total and true triglyceride concentrations.

CONCLUSIONS

The total triglyceride level overestimated the true triglyceride concentration due to fat emulsion free glycerol. To assure reliable triglyceride results in patients receiving fat emulsion, blanking for free glycerol should be considered.

Hematologic problems of the elderly

Since hemoglobin and hematocrit values tend to be low in the elderly, confirming the presence of anemia and establishing its etiology involve complex considerations. Also discussed are such proliferative disorders as chronic lymphocytic leukemia.