Hemodynamic and metabolic alterations associated with intravenous infusionof a combination of adenosine triphosphate and magnesium chloride in conscious horses

Objective-To determine hemodynamic and metabolic effects of IV infusion of ATP-MgCl2 combination and maximal safe IV infusion rate in conscious horses , Animals-6 adult female horses. Procedure-All horses received an IV infusion of AfPMgCl(2) combination, beg inning at a rate of 0.05mg of ATP/kg of body weight/min, which was increase d by 0.05 mg/kg/min increments at 10-minute intervals until a rate of 1.0 m g/kg/min was achieved. Datawere collected prior to the start of the infusio n, at the end of each infusion rate, and at 15-minute intervals for the nex t hour after discontinuation of the infusion. Measured or calculated hemody namic variables included cardiac output, cardiac index, heart rate, stroke volume, systemic and pulmonary arterial pressures, and systemic and pulmona ry vascular resistances. Arterial blood gas tensions, CBC, plasma biochemic al profiles, urine volume and specific gravity, and selected clinical signs of disease also were evaluated. Results-intravenous infusion of ATP;MgCl2 significantly increased cardiac o utput, decreased systemic vascular resistance, and caused mild pulmonary hy pertension. Magnitude of the hemodynamic alterations was dependent on rate of infusion. Maximal safe infusion rate for these horses was 0.3 mg/kg/min. All horses became lethargic, and their appetites diminished during the inf usion; 5 horses had mild signs of abdominal discomfort. Flank sweating was observed in all horses as infusion rate increased. Urine volume and specifi c gravity and hematologic, biochemical, and arterial blood gas alterations were detected during and after infusion. Conclusions and Clinical Relevance-Intravenous administration of ATP-MgCl2 in healthy, conscious; adult horses caused various metabolic and hemodynami c alterations that were without appreciable detrimental effects.