The effect of pre-operative glucose loading on postoperative nitrogen metabolism

The nitrogen sparing effect of glucose loading at either 1 mg kg-1 min-1 or 5 mg kg-1 min-1 from the evening before surgery was compared with similar glucose infusions commenced after elective surgery. Thirty-two patients undergoing abdominal surgery of moderate severity were studied. Glucose at 5 mg kg-1 min-1 reduced urea excretion compared with glucose at 1 mg kg-1 min-1. The timing of the carbohydrate infusion was not critical in altering the overall extent of the protein sparing at either rate. High dose glucose infusions markedly reduced overall urea and 3-methylhistidine excretion. This implies a reduction in protein breakdown. A pre-operative high dose infusion of glucose may in particular improve protein synthesis for the first 24 h after surgery.