Epidural analgesia enhances the postoperative anabolic effect of amino acids in diabetes mellitus type 2 patients undergoing colon surgery.

BACKGROUND It has been suggested that diabetes mellitus type 2 amplifies the endocrine-metabolic stress response to surgery, and patients become more catabolic during the postoperative period. The aim of this study, conducted in patients with diabetes mellitus type 2 scheduled to undergo elective colorectal surgery, was to determine whether the anabolic effects of intravenous amino acids are more pronounced when receiving perioperative epidural analgesia compared with patient-controlled analgesia with intravenous morphine. METHODS Twelve patients were randomly assigned to receive either epidural analgesia or patient-controlled analgesia with intravenous morphine for perioperative pain control. Protein and glucose kinetics were measured before surgery and on the second postoperative day using L-[1-C]leucine and [6,6H2]glucose infusion during a fasted and a fed (amino acid infusion) state. RESULTS Preoperative parameters for glucose and protein kinetics were comparable in the fasted state for both groups. Postoperative amino acid infusion increased glucose concentration slightly (P = 0.124) and suppressed the endogenous rate of appearance of glucose (P < 0.0001) and glucose clearance (P < 0.0001) regardless of analgesia technique. The rate of appearance of leucine (P = 0.002), leucine oxidation (P < 0.0001), and protein synthesis (P = 0.026) increased, whereas net protein breakdown was decreased (P = 0.002), leading to a positive protein balance (P < 0.0001) in both groups. The increase in protein balance was greater in the epidural group compared with the patient-controlled analgesia group (P = 0.027). CONCLUSION Diabetic patients receiving an amino acid infusion after surgery achieved a positive protein balance without hyperglycemia. This anabolic effect was greater in patients receiving epidural analgesia compared with patient-controlled analgesia with intravenous morphine.