Intraoperative epidural blockade prevents the increase in protein breakdown after abdominal surgery

Background: The aim of this study was to investigate the effect of epidural blockade with bupivacaine, restricted to the intraoperative period, on pro tein catabolism after major abdominal surgery. Methods: Fourteen patients undergoing cystoprostatectomy were randomly assi gned to receive either general anaesthesia with isoflurane (control group, n=7) or a combination of general anaesthesia and epidural blockade with bup ivacaine from segment T4 to S5 (epidural group, n=7). Rates of urea (Ra ure a) and glucose production (Ra glucose) were measured three days before and three days after the operation using stable isotope tracers ([N-15(2)]urea, [6,6-H-2(2)] glucose). Protein breakdown was calculated from the urea prod uction rate. Plasma concentrations of metabolic substrates (urea, glucose, lactate, glycerol, amino acids) and hormones (insulin, glucagon, cortisol, adrenaline, noradrenaline) were also determined. Results: Protein breakdown significantly increased after surgery in the con trol group (P <0.05), while it remained unaltered in the epidural group (co ntrol; 66 (54-76), epidural; 43 (29-58) mg . kg(-1) . h(-1), P <0.05, media n (range)). Glucose plasma concentration. and R-a glucose increased in both groups to a similar extent (P <0.05). Plasma concentration of branched cha in amino acids decreased after epidural analgesia to a value significantly lower than in the control group (P <0.05). Glutamine plasma concentration d ecreased in the control group (P <0.05), but did not change in the epidural group. There were no differences in plasma concentrations of insulin, cort isol and catecholamines between the two groups. Glucagon plasma concentrati on in the epidural group was significantly lower than in the control group (P <0.05). Conclusion: Intraoperative epidural blockade inhibits the increase in prote in breakdown after abdominal surgery.