The purpose of this study was to determine the optimal timing of intravenous
glucagon infusion for the treatment of acute occlusive
mesenteric ischemia. The superior mesenteric artery (SMA) was occluded for 85 min in 106 Sprague-Dawley anesthetized rats. The animals were divided into 12 treatment groups according to the timing of
glucagon and saline administration, and survival was measured to 48 hr. Without treatment, all rats died within 24 hr. Intravenous saline (10 ml/kg/hr) for 2 hr did not significantly improve 48-hr survival (17-33%).
Glucagon (1.6 micrograms/kg/min iv) plus saline (10 mg/kg/hr iv) for 2 hr after SMA occlusion significantly improved survival from 33% (saline control) to 83% (P less than 0.02). The same treatment begun 1 hr before SMA release (during
ischemia) did not significantly improve survival (33% at 48 hr).
Glucagon infusion during occlusive
mesenteric ischemia was detrimental when added to effective postischemia treatment, reducing survival from 83 to 33% (P less than 0.02). Adequate saline infusion was required for
glucagon efficacy after
ischemia, as shown by an intermediate 48-hr survival of 50% when only maintenance saline (1.5 ml/kg/hr) was given. These data suggest that
glucagon therapy should be delayed until after operative release of an acute SMA occlusion and should be accompanied by vigorous volume expansion.