[Comparative study of postoperative nitrogen balance as a function of carbohydrate intake]

Postoperative nitrogen intake, which limits nitrogen catabolism and improves conditions of healing, classically implies a high calorie intake. The risks and dangers of hypertonic or hypersmotic solutions are such that the provision of nitrogen postoperatively in ordinary surgery is often avoided. The authors studied postoperative nitrogen balance for a given nitrogen intake with different calorie levels in a series of 50 patients undergoing digestive surgery. A first group (28 patients--mean age 54.6 years, mean weight 63.3 kg) received 12.4 g of nitrogen and 1000 calories per day. The second group (22 patients--mean age 52.5 years, mean weight 64.7 kg) received 12.4 g of nitrogen and 2200 calories. Daily nitrogen balance was calculated using the method of approximation described by Apfelbaum on the basis of urinary urea excretion. Statistical study of nitrogen balances for the first four days showed no statistically significant difference between the mean values in the two groups. For group A, the cumulative balance for the first four days was 7.60 g +/- 4.75 g, and for group B 7.85 G +/- 6.64 g. Limitation of postoperative nitrogen catabolism does not necessarily impose the need for high calorie intake, implying the use of a central venous catheter and administration at constant flow. The patient undergoing ordinary digestive surgery may benefit from postoperative nitrogen supplies, associated with a moderate calorie intake and administered via usual venous routes.