Effect of experimental endotoxemia on thrombelastography parameters, secondary and tertiary hemostasis in dogs.

Abstract

BACKGROUND: Thrombelastography (TEG) and indicators of secondary and tertiary hemostasis might be altered in dogs with endotoxemia. HYPOTHESIS: Endotoxemia influences measures of coagulation in dogs. ANIMALS: Ten healthy cross-bred dogs. MATERIAL AND METHODS: Prospective laboratory study between controls (n = 5) receiving 0.9% saline IV and the study group (n = 5) treated with low-dose lipopolysaccharide (0.02 mg/kg IV). Physical examination and sampling for measurement of leukocytes, platelets, and coagulation variables were performed at time points 0, 1, 4, and 24 hours. Coagulation variables included kaolin-activated TEG, 1-stage prothrombin time (OSPT), activated partial thromboplastin time (aPTT), fibrinogen, factor VIII, antithrombin, protein C, protein S, activated protein C (APC)-ratio calculated from aPTT with and without presence of APC), and D-Dimers. RESULTS: Endotoxemia-induced clinical signs included lethargy (n = 5/5), diarrhea (n = 4/5), emesis (n = 4/5), and abdominal pain (2/5). After 1 hour there was severe leukopenia (2.5 &#xb1; 0.7 &#xd7; 10(9)/L; mean &#xb1; SD, P < .0001) and a 2.2-fold increase in D-Dimers (0.81 &#xb1; 0.64 mg/L, P < .0001). After 4 hours there was hyperthermia (40.3 &#xb1; 0.4&#xb0;C, P < .0001) and increases in OSPT (10.5 &#xb1; 2.7 seconds, P < .0001), aPTT (16.7 &#xb1; 5.2 seconds, P = 0.002). A significant decrease in fibrinogen (1.5 &#xb1; 1.0 g/L, P = 0.001), protein C (31 &#xb1; 33%, P < .0001), protein S (63 &#xb1; 47%, P < .0001), TEG &#x3b1; (58 &#xb1; 19, P = .007), and TEG maximal amplitude (50 &#xb1; 19 mm, P = .003) was seen compared with the controls. APC-ratio rose significantly (2.5 &#xb1; 0.2, P < .0001) without exceeding the reference interval (n = 4/5). CONCLUSION AND CLINICAL IMPORTANCE: D-Dimers are the earliest indicator for endotoxemia-associated coagulation abnormalities followed by decreased protein C concentration. APC-ratio and TEG were not good screening variables.