[Changes of whole body protein turnover due to the severity of surgical stress]

This study was conducted to understand the mechanisms underlying the loss of body nitrogen after surgical trauma. Thirteen patients who underwent moderate to severe abdominal surgery and six for control were studied. The measurement of whole body protein turnover was made on the third and tenth postoperative day during isonitrogenous and isocaloric TPN using the constant infusion method of [15N] glycine. Nitrogen balance was improved markedly in 6 patients, who received moderate surgical procedures (group I). However the balance was still negative at the tenth postoperative day in 7 patients, who received severe surgery with some critical complications (group II). A significant increase in whole body protein breakdown on the third postoperative day in groups I and II were found (p less than 0.02, p less than 0.001, respectively). Breakdown was higher in group II than in group I (p less than 0.02). Whole body protein synthesis tended to increase on the third postoperative day in group II, but was within the normal range in group I. In conclusion, the change of whole body protein turnover was different depending upon the severity of stress. Protein synthesis unchanged in moderate stress, but tended to increase in severe stress with a greater increase of breakdown.