Hypovolaemia and healing in colonic anastomoses.

Colonic anastomotic leakage is more common following emergency resections than after elective operations. Transient hypovolaemia, which is more likely to occur during emergency surgery, has been shown to impair collagen metabolism in abdominal and skin wounds but its effect on colonic anastomotic healing has not been previously examined. Acute intra-operative loss of 10 per cent circulating blood volume in rats significantly impaired collagen concentration in both ileocolic (P less than 0.02) and colocolic (P less than 0.05) anastomoses measured on the third postoperative day. This degree of blood loss did not significantly affect early anastomotic strength. Hypovolaemia leads to tissue hypoxia, and this in turn may lead to impaired anastomotic healing. Measurement of tissue oxygen tension may predict poor healing by identifying inadequate intestinal perfusion. Colonic pTO2 measured in rabbits was significantly lower than in small bowel (37 +/- 18 mmHg versus 42 +/- 18 mmHg; P less than 0.001), and fell significantly in colon following 10 per cent blood loss (P less than 0.001). We conclude that adequate intra-operative fluid replacement during colonic resection and anastomosis is a prerequisite for successful healing.