Hemostatic defects associated with two infusion rates of dextran 70 in dogs

We investigated changes in hemostatic function after infusion of 6% dextran 70 (high molecular weight dextran) at 2 rates. Six healthy dogs underwent 3 regimens: 20 ml of dextran/kg of body weight administered in 1 hour (trial A), 20 ml of dextran/kg administered in 30 minutes (trial B), and 0.9% sodium chloride solution as a control administered over 1 hour to achieve hemodilution equivalent to that for 20 ml of dextran/kg (trial C). Before and at 2, 4, 8, and 24 hours after the start of trials A and B, we measured PCV, total solids (TS) concentration, amount of von Willebrand factor antigen (vWF-Ag), factor VIII coagulant activity (VIII:C), prothrombin time, activated partial thromboplastin time (APTT), platelet retention in a glass bead column, and buccal mucosa bleeding time (BMBT). Values were not obtained at 8 and 24 hours for trial C. Saline-induced changes in hemostasis were significant (P < 0.05) from baseline throughout the sample collection period. Significant differences (P < 0.05) between trial A and control were observed for vWF:Ag, VIII:C, BMBT, APTT, TS, and PCV values at 2 hours, and for VIII:C at 4 hours. Significant differences (P < 0.05) between trial B and control were observed for APTT, TS, and PCV values at 2 hours, and for vwf-ag, VIII:C, BMBT, APTT, TS, and PCV values at 4 hours. During trials A and B, mean values of analytes infrequently deviated from reference intervals, and clinical signs of bleeding were not observed in any dog. Data for the dextran infusions paralleled each other and had a tendency to normalize, infrequently reaching baseline by 24 hours. Differences in overall hemostatic function were not detected between dextran infusions. Dextran 70 +/- a dosage of 20 ml/kg induces minimal hemostatic abnormalities when infused over 30 or 60 minutes to clinically normal dogs, but may precipitate bleeding in dogs with marginal hemostatic function.