Twenty‐four hour hyperinsulinemic‐euglycemic clamp improves postoperative nitrogen balance only in low insulin sensitivity patients following cardiac surgery

Background Critically ill patients often suffer from a protein catabolic state. The aim of this study was to demonstrate that nitrogen balance ( NB ) in cardiac patients admitted to the intensive care unit ( ICU ) is related to their insulin sensitivity level and that supraphysiologic doses of insulin can restore anabolism. Materials and methods Twenty‐eight patients that were admitted to ICU in enteral and/or parenteral nutrition have been enrolled in this study. All patients received a standard nutrition protocol for at least 3 days before starting the study. These patients received either enteral or parenteral nutrition based on 1.4 kcal/kg/h and 1.1 g/kg/24 h of proteins. Participants were studied for three 24 h periods (P 1 , P 2 , and P 3 ). Twenty‐four hour NB was calculated from urinary urea nitrogen excretion, fixed protein and energy intake during each of the three periods (P 1 , P 2 , and P 3 ). Simultaneous to P 2, a 24 h hyperinsulinemic‐euglycemic clamp ( HEC ) was performed to determine patients’ insulin sensitivity ( IS ) or insulin resistance ( IR ), as well as the impact of high doses of insulin on NB . Results Nitrogen balance remained consistently positive in the IS group regardless of the clamp. In IR patients, NB was negative before the clamp and became positive during P 2 and P 3 . Insulin sensitivity improved during the HEC in IR patients ( P  < 0.001). Conclusions A negative NB was found only in insulin resistant patients admitted to the ICU for more than 7 days. A 24‐h period HEC improved NB in these patients.