Randomized clinical trial of the effects of immediate enteral nutrition on metabolic responses to major colorectal surgery in an enhanced recovery protocol

Abstract

Abstract Background The effects of immediate postoperative enteral nutrition on postoperative nitrogen balance and insulin resistance were studied in patients subjected to an enhanced-recovery protocol. Methods Eighteen patients undergoing major colorectal surgery in an enhanced-recovery protocol were randomized to immediate postoperative enteral feeding for 4 days with either complete or hypocaloric nutrition. Nitrogen balance and changes in glucose kinetics, substrate utilization (indirect calorimetry) and insulin sensitivity (hyperinsulinaemic–euglycaemic clamp) were measured. Values are mean(s.e.m.). Results Mean postoperative urinary nitrogen losses were low (10·7(1·0) versus 10·5(0·7) g per day for complete versus hypocaloric nutrition) and insulin resistance was insignificant (−20(7) versus − 27(11) per cent), with no difference between groups. Complete enteral feeding was given without hyperglycaemia (blood glucose concentration 5·8(0·4) versus 5·0(0·4) mmol/l) and resulted in nitrogen balance (+0·1(0·8) versus − 12·6(0·6) g nitrogen per day; P < 0·001). Conclusion This enhanced-recovery protocol was associated with minimal postoperative insulin resistance and nitrogen losses after surgery. Immediate postoperative enteral nutrition was provided without hyperglycaemia and resulted in nitrogen balance.