197 NALOXONE INDUCED GUT ISCHEMIA DURING RESUSCITATION OF EXPERIMENTAL NEONATAL SEPTIC SHOCK

Abstract

Naloxone has been recommended for use in neonatal septic shock. To evaluate its effectiveness in peritonitis-induced septic shock, anesthetized newborn pigs were monitored and peritonitis was induced by intraperitoneal injection of E.coli and sterile pig feces. All pigs received fluid resuscitation, gentamicin, and bicarbonate to correct acidemia. When shock was evident, the pigs either received an initial IV bolus of naloxone (2 mg/kg) followed by a 2 mg/kg.hr infusion (Group I, n=9), or received no additional pharmacological intervention (Group II, n=7). Hemodynamic parameters assessed included mean arterial, pulmonary arterial, and central venous pressures; cardiac, stroke volume, and left ventricular stroke work indices; and systemic and pulmonary vascular resistance indices. There were no significant differences in any of the parameters measured between Groups I and II, although peripheral vascular resistance in Group I was transiently elevated acutely after naloxone infusion began. Mean survival times in the two groups were similar. Five of 9 Group I animals (56%), demonstrated gross and histologically proved intestinal ischemia (p<.02) while none of the animals in Group II demonstrated any notable sequelae. The data demonstrate that naloxone resuscitation results in an increase in vascular resistance without concomitant improvement in cardiac performance. These changes are associated with significant intestinal ischemia in this model.