Epidural blockade improves substrate utilization after surgery

The purpose of this study was to test the hypothesis that epidural blockade with local anesthetic improves the anticatabolic effects of glucose after colorectal surgery. Sixteen patients were randomly assigned to undergo a 6- h stable isotope infusion study (3 h fasted, 3 h glucose infusion at 4 mg.k g(-1).min(-1)) on the second postoperative day with or without perioperativ e epidural blockade. Protein synthesis, breakdown and oxidation, and glucos e production and clearance were assessed by L-[ 1-C-13] leucine and [6,6-H- 2(2)]glucose. Epidural blockade did not affect protein and glucose metaboli sm in the fasted state. Glucose infusion increased glucose clearance (P< 0. 05), accompanied by an increase in the respiratory quotient (P< 0.05) and a decrease in leucine oxidation (P< 0.05) only in the presence of epidural b lockade. An inverse correlation (r = -0.74, P< 0.05) between changes in glu cose clearance and leucine oxidation was observed. In conclusion, epidural blockade facilitates whole body glucose uptake and inhibits endogenous prot ein oxidation after abdominal surgery, indicating a shift from a protein to a more glucose-dominated substrate utilization.