Failure of exogenous ATP and creatine phosphate to modify the course of E coli endotoxin shock in the cat

Exogenous adenosine triphosphate (ATP) (in combination with MgCl2) and also creatine phosphate (CrP), have been administered intravenously to endotoxin-shocked cats. Untreated shocked cats exhibited systemic hypotension during the first hour and again from four hours. Cardiac output fell progressively, and markedly elevated arterial lactate levels were evident within one hour of endotoxin administration. Treatment with ATP (10 mg/kg every 30 minutes) during shock led to rapid hemodynamic deterioration in all cats; most of the cats were dead before completion of dosing (at three hours). Long-lasting systemic hypotension and bradycardia were associated with this ATP administration and marked hypoglycemia developed in the survivors. Neither ATP (62 mg/kg) administered before endotoxin, nor CrP (500 mg/kg; administered either prior to endotoxin, or one hour afterwards) significantly modified the hemodynamic or metabolic changes associated with endotoxin shock in this species. Neither ATP nor CrP increased survival (assessed at five hours). Other workers have demonstrated improved survival from shock with ATP treatment. There may be species differences in the responsiveness to exogenous ATP or, alternatively, a difference in the role of high-energy phosphates in different types of shock.