Cardiovascular and Hematological Effects of Hetastarch and Hypertonic Saline Solutions During Experimental Endotoxemia in Horses

Justification: Endotoxemia and sepsis are major causes of mortality in horses, resulting in significant economic losses for the equine industry.

Objective: To determine the effects of the combination of Hypertonic Saline Solution and Hetastarch in endotoxemic horses.

Animals: Eighteen horses divided into three groups of six.

Procedure: All horses received a total dose of intravenous E. coli endotoxin infused at 50 ug/kg; divided into a bolus infusion of 20 ug/kg followed by 30 ug/kg given over 30 minutes. After induction of endotoxic shock; group I (control) received a bolus (15 ml/kg) of isotonic solution, group II (isotonic solution) received a bolus (60 ml/kg) of balanced polyionic crystalloid solution and group III (Hypertonic saline plus Hetastarch) received a bolus of 5 ml/kg of hypertonic saline, followed by a bolus of 10 ml/kg of Hetastarch. Hemodynamic and hematological parameters were measure at different time points.

Results: Hemodynamic, biochemical and hematological differences were observed among the three groups.

Conclusions and Relevance: the use of large volume crystalloid fluid resuscitation causes volume overload, exerting deleterious effects on the cardiovascular and pulmonary systems. The use of small volume resuscitation (HSS-HES) showed a trend towards better cardiovascular and pulmonary function, without the deleterious effects of volume overload. Abnormalities with regard to coagulation were not seen for the time period of the experimental protocol and the dose regimen used for HSS-HES. Small volume resuscitation in critically ill horses shows promise for its beneficial effects in cardiovascular and pulmonary functions.