In vitro effects of lipid emulsion on platelet function and thromboelastography in canine blood samples

OBJECTIVE: To determine whether soybean oil emulsion has an in vitro effect on platelet aggregation and thromboelastography in blood samples obtained from healthy dogs. ANIMALS: 12 healthy adult dogs. PROCEDURES: Blood samples were collected from each dog into tubes containing EDTA, hirudin, or sodium citrate for a CBC, collagen- and ADP-induced impedance aggregometry, or thromboelastography, respectively. Whole blood platelet aggregation, determined with ADP or collagen agonists, was measured in blood samples containing hirudin and final lipid concentrations of 0, 1, 10, and 30 mg/mL. The thromboelastographic variables R (reaction time), K (clotting time), α angle, and maximum amplitude were evaluated in blood samples containing sodium citrate and final lipid concentrations equivalent to those used for assessment of platelet aggregation. RESULTS: Median maximum ADP- and collagen-induced platelet aggregation in blood samples containing 1, 10, or 30 mg of lipid/mL did not differ significantly from the value for the respective lipid-free blood sample. Maximum amplitude determined via thromboelastography was significantly reduced in blood samples containing 10 and 30 mg of lipid/mL, compared with findings for lipid-free blood samples. Values of other thromboelastographic variables did not differ, regardless of lipid concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Maximum amplitude determined via thromboelastography in canine blood samples was significantly affected by the addition of lipid to final concentrations that are several orders of magnitude higher than clinically relevant lipid concentrations in dogs. Lipid treatment appears to have no significant effect on hemostatic variables in dogs, although clinical studies should be performed to confirm these in vitro findings.