Metabolic, water and electrolyte changes after moderate surgical trauma. Observations after different schedules of parenteral nutrition.

The effects of a moderate surgical trauma on body composition, in conditions comparable to fasting were assessed in a balance study. Two groups of patients under normal nutritional conditions were compared after cholecystectomy. The patients underwent for three days the following schedules of parenteral therapy: incomplete nutrition with balanced intake of water, sodium and potassium but carbohydrate deficient and lacking in amino acids (group 1, 10 cases); or complete nutrition with respect to calories, amino acids and other electrolytes (group 2, 9 cases). An evident loss in body weight was observed in patients undergoing incomplete nutrition, not justified by a moderately negative water balance. Statistical comparison of the two groups showed equal or positive balances for group 1 while group 2 gave negative results for all the parameters, particularly for nitrogen and potassium, suggestive of a loss in lean body mass greater than that usually occurring after simple fasting. Results confirmed the poor significance of serum values in expressing even significant degrees of electrolyte depletion. Substantial modifications in body composition may appear as clinical manifestations in cases with pre-existing malnutrition or when drugs that affect or are affected by the water and electrolyte balance are administered.