Comparative effects of dopamine, naloxone, and prostacyclin in the resuscitation of fecal-Escherichia coli peritonitis-induced septic shock in neonatal swine.

To explain the high neonatal mortality from peritonitis-induced septic shock despite current resuscitation practices, the efficacy of dopamine, naloxone, and prostacyclin was evaluated in an experimental neonatal model. Hemodynamics were monitored and survival was measured in anesthetized neonatal swine, which were subjected to fatal fecal-Escherichia coli peritonitis-induced septic shock. All the animals received fluid resuscitation, antibiotics, and bicarbonate to correct acidosis. Pharmacologic resuscitation began when cardiac output dropped below baseline in the experimental groups. Although significant differences were observed between groups in cardiac output, mean arterial and mean pulmonary arterial pressures, left ventricular stroke work, stroke volume, and pulmonary vascular resistance indices (P less than 0.02), and each animal exhibited favorable hemodynamic responses during the first several hours of dopamine and naloxone infusion, these drugs failed to prolong survival. Also, 5 of the 9 naloxone-treated pigs (56%), died with histologically proven intestinal ischemia (P less than 0.02). Thus, dopamine, naloxone, and prostacyclin (at doses commonly recommended for the treatment of septic shock) fail to positively influence the fatal course of this condition, and the use of naloxone in this model is associated with profound intestinal ischemia.