Prevention of secondary cardiovascular instability after intestinal ischemia and reperfusion improves survival

Previous studies of small intestinal ischemia and reperfusion (I/R) in immature rats report secondary systemic organ injury and low survival rates; however, in these studies the cardiovascular stability of the rat was not established. To prevent the secondary hemodynamic deterioration accompanying intestinal I/R, we have developed a model that utilizes aggressive fluid resuscitation. Under anesthesia, 4-wk-old male Sprague-Dawley rats (n = 189) underwent 90 min of I/R (superior mesenteric artery occlusion) or sham (SH) operation while receiving lactated Ringer with 5% dextrose at 15 (IR15, SH15) or 65 (IR65, SH65) ml.kg-1 x h-1 i.v. The results indicate that aggressive fluid resuscitation in the IR65 group significantly attenuated the hypotension, hemoconcentration, metabolic acidosis, and amount of gross bowel injury observed in the IR15 group, while increasing postreperfusion renal and intestinal blood flow, prolonging survival time of nonsurvivors, and improving overall group survival. These findings suggest that maintenance of hemodynamic stability is necessary in models of bowel I/R. Furthermore, this model allows for selective study of the isolated effects of intestinal I/R without the additional complications resulting from secondary cardiovascular instability.