EFFECT OF ANESTHESIA AND LAPAROTOMY ON BLOOD-FLOW TO THE STOMACH, SMALL BOWEL, AND COLON OF THE DOG

Abstract

The effect of anesthesia and laparotomy in the distribution of blood flow to the different tissue layers of the stomach, small bowel and colon of the dog was studied using a double-isotope, microsphere technqiue. In conscious dogs, total jejunal flow significantly exceeded ileal and colonic flow. Mucosal flow comprised .apprx. 2/3 of total gastric and small bowel flow, but less than 1/2 of colonic flow. There was a marked increase in flow to all levels of the alimentary tract, and to each tissue layer 15 min after anesthesia induction. This increase was transient, since by 1 h flow to all gut levels had nearly decreased to baseline levels. Laparotomy per se did not significantly alter blood flow to the full thickness or mucosal layer of the stomach, small bowel or colon. Future studies of gut function or blood flow evidently should be performed in conscious animals or in anesthetized animals only after complete cardiovascular stabilization. Neither laparotomy nor anesthesia caused a redistribution of flow away from the mucosal layers, and hence the observation that patients have often stopped bleeding at the time of operation for uncontrolled hemorrhage is unexplained.