Influence of Injury and Nutrition on Muscle Water and Electrolytes

Abstract

Injury is followed by a sequence of metabolic alterations which include fluid and sodium retention. This study used the percutaneous biopsy technique to analyze changes in muscle composition in regions nonadjacent to the area of surgical injury. The effect of nutritional intake on the changes observed in emphasized. Twenty-eight patients undergoing colectomy and 22 patients undergoing total hip replacement were studied. The patients undergoing colectomy resections received total parenteral nutrition with varying nitrogen intake. The patients undergoing hip replacement received either a) 5% dextrose solutions, b) 3.5% amino acid solutions, or c) both. Muscle biopsy procedures were performed preoperatively and postoperatively (day three on the colectomy patients) (day four on the hip replacement patients). The role of inactivity was assessed in eight healthy subjects maintained on strict bedrest for four days. Four subjects received a regular diet, while four received 5% dextrose solution for four days. The tissue samples were analyzed for water, sodium, chloride, potassium, magnesium, and in selected cases glycogen. No significant effects of bedrest with either a regular diet or semistarvation were observed. Surgical injury caused an increase in muscle water, sodium, and chloride while there was a slight reduction in potassium in all groups, with the exception of those colectomy patients who received no amino acids after operation. There was no effect of varying the level of nitrogen intake in the colectomy patients, nor was there an effect of different hypocaloric infusions, in the hip replacement patients. The colectomy patients on admission to the hospital, showed some signs of prior nutritional depletion. After receiving four days of preoperative nutrition, there was a decrease in extracellular water, in sodium and chloride towards normal values. Following injury, there was an increase in muscle water, sodium and chloride, while potassium decreased slightly. In the postoperative period there were only minimal effects of nutritional intake on the observed changes.