Intestinal ischemic injury following mild hypothermic stress in the neonatal piglet.

The core body temperature of unanesthetized neonatal piglets was lowered 4 +/- 1 degrees C for 4.5 h. Although systolic blood pressure, arterial blood gases, and pH were similar in hypothermic and control animals, grossly evident small intestinal injury occurred in 94% of hypothermic piglets but in none of the controls (p less than 0.01). The histopathology of the intestinal lesions in the experimental animals was characteristic of ischemic injury and ranged from superficial mucosal necrosis to transmural infarct. The lesions were more frequent in the mid- and distal small bowel and involved the muscularis propria only in the distal small bowel. The location and histopathologic characteristics of the bowel lesions in these animals support the concept that mild hypothermia could be a pathogenetic factor in the ischemic bowel lesions of human neonatal necrotizing enterocolitis.