Effects of oxypolygelatin and dextran 70 on hemostatic variables in dogs.

OBJECTIVE

To evaluate and compare coagulation variables following the administration of oxypolygelatin and dextran 70 to clinically healthy dogs.

STUDY

DESIGN

Randomized cross-over experimental study.

ANIMALS: A total of eight healthy adult female Beagles aged 2-4 years old and weighing 11.8 +/- 2.7 kg.

METHODS

The dogs received a 15-minute intravenous (IV) infusion of 5 mL kg-1 oxypolygelatin or 10 mL kg-1 6% dextran 70. Before (PRE) and at 2, 5, and 24 hours after administration, packed cell volume (PCV), total solids concentration (TS), prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen concentration (FIB), platelet numbers (Plat), factor VIII coagulant activity (VIII:C), von Willebrand factor antigen concentration (vWf:Ag) and platelet function and buccal mucosal bleeding time (BMBT) were measured. Platelet function was assessed using aggregation and by measuring ATP release from aggregating platelets over 6 minutes, with 20, 10, and 5 micro m ADP and 5 and 10 micro g of collagen mL-1 as platelet activation agonists.

RESULTS

All baseline values were within our normal ranges, except for one dog that had low vWf:Ag PRE values prior to both dextran and oxypolygelatin administration. Following dextran and oxypolygelatin administration, the PCV and TP were significantly (p < 0.05) decreased. Plat, FIB, and vWf:Ag decreased, while BMBT and VIII:C increased following dextran administration. Dextran also caused a significant decrease in platelet aggregation in response to ADP. Oxypolygelatin caused a significant decrease in vWf:Ag, Plat, and FIB compared to PRE values. The total amount of ATP released, standardized to platelet number, did not vary significantly for either group at any sampling time from PRE values. No significant changes from PRE values were noted at any time in either group for PT or APTT.

CONCLUSION

At the doses administered, both dextran and oxypolygelatin can interfere with hemostatic variables in healthy dogs, but dextran's effect is more profound and prolonged when compared to oxypolygelatin.

CLINICAL RELEVANCE: Oxypolygelatin causes fewer hemostatic abnormalities when compared to dextran, making it a superior colloid for administration at the doses tested.