Importance of dehydration in anastomotic and subcutaneous wound healing: an experimental study in rats.

Objective: To find out if preoperative and postoperative dehydration adversely affect anastomotic and subcutaneous healing.

Design: Randomized study.

Material: 18 Wistar rats.

Interventions: Dehydration established in nine rats by withdrawal of food and water for 24 hours before operation, and by injections of frusemide twice daily. Laparotomy and division of intestine 5-8 cm from the ileocaecal valve. Implantation of expanded polytetrafluoroethylene (ePTFE) tubes in the backs of the necks. All rats killed after five days.

Main Outcome Measures: Measurements of weight loss and of hydroxyproline per centimetre in the ePTFE tubes and standardized biopsy specimens of the intestine. Presence of anastomotic dehiscence at necropsy.

Results: Preoperative and postoperative dehydration caused a 24% weight loss in the experimental group on day 5 compared with 8% in the control group. Dehydrated animals accumulated less collagen in the ePTFE tubes than control animals (p less than 0.05). There were three anastomotic breakdowns in the dehydrated group compared with one in the control group. There was a loose but significant correlation between collagen accumulation in the anastomoses and the weight of the animal (r = 0.5, p less than 0.05).

Conclusion: Preoperative and postoperative dehydration has a deleterious effect on subcutaneous, and to a lesser extent on anastomotic healing in rats.