Parenteral amino acid supplementation with high dose insulin prevents hypoaminoacidemia during cardiac surgery

ABSTRACT Objective Surgery triggers a stress response that produces insulin resistance and hyperglycemia. During cardiac surgery, administration of high dose insulin along with dextrose titration maintains normoglycemia, but dramatically decreases plasma amino acids (AAs) compared to pre-operative fasting levels. Hypoaminoacidemia limits protein synthesis and prevents anabolic responses after surgery. We investigated whether parenteral infusion of AA during and immediately after cardiac surgery would prevent hypoaminoacidemia in patients receiving high dose insulin therapy. Methods Sixteen patients undergoing coronary artery bypass grafting (CABG) surgery were randomly allocated to receive AAs with % kcal equivalent to either 20% (n=8) or 35% (n=8) of their measured resting energy expenditure (REE). Insulin was infused at constant rate of 5 mU/(kg•min) while dextrose was titrated to maintain normoglycemia during and until 5 hours after surgery. Plasma AA concentrations were measured at baseline before and after surgery. Results Compared to the 20% AA group after surgery, AA concentrations were significantly higher in the 35% AA group for 12 out of 20 AAs (p Conclusion AA supplementation at 35% REE, but not 20% REE, can effectively prevent hypoaminoacidemia caused by high dose insulin therapy during cardiac surgery.