Low molecular weight dextran in the treatment of necrotizing enterocolitis and midgut volvulus in infants

Cytoprotective agents in experimental small bowel volvulus

An accepted experimental model for midgut volvulus was used to produce small bowel strangulation obstruction of 48 hours duration in Sprague-Dawley rats. A 93% perioperative mortality rate resulted after release of the volvulus. Treatment with three cytoprotective agents at the time of volvulus release resulted in the following mortality rates: superoxide dismutase, 89%; ibuprofen, 50%; prostaglandin E1 (PGE1, 11%. The predominant cause of death in all treatment groups was bowel infarction, with a smaller number succumbing to either sepsis or circulatory collapse. Concomitant administration of ephedrine or indomethacin to suppress prostaglandin E1's splanchnic vasodilatory activity did not cause any increase in mortality. A trial of aspirin, to simulate PGE's antiplatelet actions, showed no reduction in mortality when compared with detorsion alone. Prostaglandin E1 and, to a lesser extent, ibuprofen, appear to have cytoprotective effects during reperfusion of bowel compromised by volvulus, independent of their influence on the mesenteric vasculature and thrombogenesis.

A mouse model for the study of necrotizing enterocolitis

A mouse model for the study of necrotizing enterocolitis is presented. It is a model of temporary intestinal ischemia and consists of occluding both superior mesenteric vessels with a bulldog clamp for varying periods of time. The resultant lesions resemble the intestinal lesions seen in necrotizing enterocolitis in respect to the gradual development of the necrotizing lesions and their patchy distribution. We also studied the effect of intravenous saline and low molecular weight dextran in preventing the development of these ischemic lesions. In moderate ischemia, saline and dextran show a similar protective effect, and in severe ischemia, both show a protective effect, with dextran being more effective than saline.

Routine contrast enemas for diagnosing and managing strictures following nonoperative treatment of necrotizing enterocolitis

A study to determine the value of contrast enemas in diagnosing and managing intestinal strictures following nonoperative treatment of necrotizing enterocolitis was performed from 1978 through 1983. From 1974 through 1977, 17 patients survived nonoperative treatment of NEC and three developed symptomatic strictures, an incidence of 18% (3/17). Since then a total of 31 infants were treated for NEC; three patients survived operation for perforation and there were seven deaths, leaving 21 in the study group. Sixteen patients had contrast enemas three to six weeks after resolution of NEC, which revealed strictures in five patients. Four of the five patients with strictures demonstrated on contrast enema were without obstructive symptoms. Three of the four remained asymptomatic without treatment, and one eventually required surgery for intestinal obstruction. The fifth patient developed intestinal obstruction while still in the nursery and a contrast study demonstrated an ileal stricture. A sixth patient had a normal contrast study and developed intestinal obstruction from an ileal stricture. The incidence of strictures was 38% (6/16). In five patients, appointments for contrast studies were not kept, although clinical follow-up was complete in all. The incidence of symptomatic strictures for the contrast study period was therefore 14% (3/21). Although some authors have recommended routine contrast enemas in patients surviving nonoperative treatment of NEC, contrast enemas had no advantage over clinical follow-up in the management of patients in this study. We have discontinued the use of routine contrast enemas in favor of close follow-up and careful instruction to parents as to the early signs of intestinal obstruction.

Low molecular weight dextran and reexploration in the management of ischemic midgut-volvulus

Administration of low molecular weight dextran and reexploration in 36-48 hr, is recommended in cases of ischemic midgut volvulus. Five cases are presented utilizing this technique and many centimeters of small bowel were saved that would have been resected at time of the original exploration. One patient died as a result of sepsis due to central intravenous nutrition: the others are alive and well.

Necrotizing enterocolitis in term infants

Despite the fact that necrotizing enterocolitis is considered a disease of premature infants, 20% of all affected infants at Babies Hospital over the past 20 years were products of term gestations. Two distinct subgroups of such infants were noted (1) five infants with congenital heart disease and/or congestive heart failure (e.g.hypoplastic left heart syndrome), all but one of whom developed the disease in the first week of life; (2) eight infants who developed the disease at a much later age after a protracted period of diarrhea. This histopathologic features of the disease in term infants are the same as those in premature infants. Further, the pathogenesis of the disease in term infants does not appear to differ basically from that in premature infants. These facts, lead away from the concept of NEC as a disease of simple etiology.