Effects of Small‐ and Large‐Volume Resuscitation on Coagulation and Electrolytes during Experimental Endotoxemia in Anesthetized Horses

Background : Small‐volume resuscitation (SVR) has been advocated in place of large‐volume isotonic resuscitation for the treatment of endotoxemia in horses. The effects of this type of therapy during experimental endotoxemia on electrolytes and coagulation have not been evaluated in the horse. As part of a larger project, the objective of this study was to determine the effects of SVR (hypertonic saline solution [HSS] plus hetastarch [HES]) on coagulation and serum electrolytes concentration, and to compare SVR with large‐ and small‐volume isotonic resuscitation during experimental endotoxemia in anesthetized horses. Hypothesis : SVR does not affect coagulation parameters or serum electrolyte concentrations when compared with either small‐ or large‐volume isotonic crystalloids. Animals : Horses were randomly assigned to 1 of 3 groups. Under halothane anesthesia, endotoxemia was induced by administering 50 ?g/kg Escherichia coli endotoxin IV. The horses were treated for 30 minutes with 15 mL/kg of balanced polyionic crystalloid solution (control), 60 mL/kg of balanced polyionic crystalloid solution (ISO), or 5 mL/kg of HSS followed by 10 mL/kg HES (HSS‐HES). Methods : Prospective randomized trial. Results : Significant differences in coagulation parameters were not found among the groups. Thrombocytopenia was severe in all 3 groups. Serum ionized calcium concentration significantly decreased from baseline in control and ISO groups but not in the HSS‐HES group. Conclusions and Clinical Importance : These results suggest that the HSS‐HES combination, at the dosage used in this study had no adverse effects on coagulation beyond those produced by endotoxemia. HSS‐HES may have a protective effect against endotoxemia‐induced ionized hypocalcemia.