In dogs, indications for colloid use include hypovolemic or distributive shock and hypoalbuminemia/decreased oncotic pressure. Tetrastarch is a third-generation hydroxyethyl starch with a smaller molecular weight and lower degree of molar substitution, and, thus, more rapid elimination and lack of accumulation as compared with other hydroxyethyl starches. Reports posit a possible lesser impact of tetrastarch on coagulation as well.
This randomized, placebo-controlled, blinded study aimed to compare the effects of an isotonic crystalloid and a synthetic colloid on coagulation in healthy dogs and in dogs with systemic inflammation. A secondary goal was to determine the correlation between thromboelastography (TEG) variables and traditional coagulation tests.
Healthy beagles (n = 16) were randomized into 2 fluid resuscitation groups: 40 mL/kg IV of either 0.9% NaCl or tetrastarch. Each dog was subjected to 2 treatment phases 2 weeks apart: placebo vs lipopolysaccharide to mimic systemic inflammation, followed by fluid resuscitation as assigned. Blood samples at 0, 1, 2, 4, and 24 hours were analyzed for coagulation and TEG variables. All dogs had similar increases in prothrombin time and activated clotting time. Compared with saline administration, tetrastarch resulted in prolonged aPTT, hypocoagulable and hyperfibrinolytic TEG variables, and significantly decreased platelet count and von Willebrand factor antigen in both healthy (placebo) and systemically inflamed dogs; all resolved within 4 hours. The traditional coagulation tests had weak correlations with TEG values.
Results indicated that tetrastarch induced a transient hypocoagulable and hyperfibrinolytic state. However, most coagulation variables were within reference ranges, which makes the clinical significance uncertain.