Effect of laparoscopic colon resection on postoperative glucose utilization and protein sparing: an integrated analysis of glucose and protein metabolism during the fasted and fed States using stable isotopes.

HYPOTHESIS

Using a stable isotope method to quantify postoperative changes in glucose and protein metabolism, patients undergoing laparoscopic-assisted colon resection and receiving 4 mg . kg(-1) . min(-1) of dextrose intravenously will (1) have more pronounced suppression of endogenous glucose production, leading to (2) a greater reduction in whole-body protein breakdown.

DESIGN

Randomized protocol study.

SETTING

Tertiary health care center in Montreal, Quebec.

PATIENTS

Twelve patients scheduled for colonic resection were randomly allocated to undergo either laparoscopic (n = 6) or open (n = 6) surgery.

INTERVENTIONS

Patients underwent a 6-hour stable isotope infusion study (3 hours fasted and 3 hours fed with dextrose infusion) on postoperative day 2. Whole-body protein breakdown and synthesis, amino acid oxidation, and endogenous glucose production and clearance were measured during the postabsorptive state using L-[1-(13)C]leucine and [6,6-(2)H(2)]glucose. Gas exchange and plasma concentrations of metabolites and hormones were also measured.

MAIN OUTCOME MEASURES

Endogenous glucose production and whole-body protein breakdown during the fasted and fed states.

RESULTS

In the fasted state, laparoscopy did not affect protein and glucose metabolism. Dextrose infusion suppressed endogenous glucose production in both groups, with the greatest extent in the laparoscopic group (P = .01). Higher respiratory quotients (P = .001) in the latter group also indicated increased exogenous glucose oxidation. Neither surgical approach nor nutrition affected aspects of protein metabolism.

CONCLUSIONS

Laparoscopy for colon resection facilitates whole-body glucose uptake and utilization and oxidation of exogenous glucose with no protein-sparing effect. The laparoscopic approach modulates gluconeogenesis, although it is not sufficient in the presence of exogenous energy to promote nitrogen retention.