Effects of Tetrastarch Administration on Hemostatic, Laboratory, and Hemodynamic Variables in Healthy Dogs and Dogs with Systemic Inflammation
Hydroxyethyl starches (HES) are the most routinely used synthetic colloids during fluid resuscitation and have reported effects on coagulation. The overall goal of the investigation in this thesis was to evaluate the effects of tetrastarch administration on hemodynamic, laboratory, and hemostatic variables in healthy dogs and dogs with systemic inflammation. The objectives were to compare hemodynamic and laboratory variables in dogs receiving an isotonic crystalloid (0.9% NaCl) or tetrastarch during health and after induction of systemic inflammation; to compare the hemostatic effects of an isotonic crystalloid (0.9% NaCl) and synthetic colloid (tetrastarch) in healthy dogs and dogs with induced systemic inflammation; to compare two different protocols for TEG® activation and to determine the correlation between TEG® variables and traditional coagulation test results. Sixteen adult purpose-bred Beagles were randomized into one of two groups receiving fluid resuscitation with either 40 mL/kg IV isotonic crystalloid (0.9% NaCl) or synthetic colloid (tetrastarch) after administration of lipopolysaccharide (LPS; 5 μg/kg, IV) or an equal volume of placebo (0.9% NaCl, IV). Blood samples, for analysis, were collected at 0, 1, 2, 4, and 24 hours from the time of fluid resuscitation. After a 14-day washout period, the study was repeated such that dogs received the opposite treatment (LPS or placebo) and the same resuscitation fluid. Resuscitation with equal volumes of 0.9% NaCl and tetrastarch caused similar changes in hemodynamic and laboratory variables in dogs with LPS-induced systemic inflammation; however, larger increases in HR and blood pressure were seen within the first 2 hours following tetrastarch administration compared to 0.9% NaCl. Tetrastarch administration increased COP in all dogs, despite a decrease in TS. Tetrastarch bolus administration to dogs with LPS-induced systemic inflammation also resulted in a transient hypocoagulability characterized by a prolonged PTT, decreased clot formation speed and clot strength, and acquired type 1 von Willebrand disease. Considering the limited additional benefit of tetrastarch administration on hemodynamic variables demonstrated, as well as the transient adverse hemostatic effects of tetrastarch administration, the increased cost associated with the use of tetrastarch likely negates its use as a first line treatment during fluid resuscitation in dogs.