ATP-MgCl2 pre-treatment in an animal model of asphyxial arrest.

ATP-MgCl2 treatment has been found to be a promising intervention in many models of hypoxic/ischemic injury. In this study, the effect of pre-treatment with ATP-MgCl2 on the hemodynamic response to asphyxia in the rat was examined. Rats were anesthetized with halothane and N2O2. A tracheostomy and femoral artery and vein cutdowns were performed. Rats were infused intravenously with either ATP-MgCl2 (approximately 50 mumol/kg) or normal saline (control group) over 15 min. Animals were then asphyxiated for 8 min by occlusion of the ventilator tubing. Following the asphyxia, 1 min of cardiopulmonary resuscitation (CPR) was attempted. Heart rate and blood pressure were monitored continuously throughout the experiment. A total of 41 animals (21 ATP-MgCl2, 20 control) were studied. Analysis of variance (ANOVA) was used to test for differences between groups. The ATP-MgCl2 group had a lower heart rate (HR) and mean arterial pressure (MAP) during the infusion. During asphyxia the ATP-MgCl2 group had a lower MAP but higher HR when compared to the control group. No significant differences were observed in the rates of successful resuscitation between ATP-MgCl2-treated rats (10 of 21, 48%) and controls (12 of 20, 60%). Possible reasons for the apparent lack of benefit of ATP-MgCl2 therapy are discussed.