Bacterial microflora, endogenous endotoxin, and prostaglandins in small bowel obstruction.

The objective of this experimental study of small bowel obstruction was to investigate luminal bacterial colonization and assess the most likely mediator substances responsible for the pathophysiologic alterations, those being endogenous endotoxin and prostaglandins. Eighteen pigs with small bowel obstruction and 11 sham-operated control animals given constant infusion therapy were investigated over 7 days. Bacteria determinations were performed at operation and at sacrifice. Endotoxin levels were determined three times and prostaglandin levels, twice daily in portal and central venous blood. In the pigs with small bowel obstruction, greatly increased microflora with a predominance of E. coli bacteria was observed in the obstructed bowel. Endotoxin measurements proved general release into the circulation, with potentially toxic levels in the systemic circulation arising relatively late on the fourth postobstruction day. Beginning on the first postobstruction day, stimulation of the prostaglandin system occurred which was initially limited to the gastrointestinal tract but spread systemically when the obstruction persisted for more than 5 days. Vasoactive eicosanoids were predominantly involved. The control animals showed none of the alterations seen in the animals with small bowel obstruction.