Effects of glucocorticoids on serum amino acid levels during cardiac surgery in children

Abstract

Children undergoing cardiac surgery with cardio pulmonary bypass often receive glucocorticoids to reduce the systemic inflammatory response. Glucocorticoids stimulate protein breakdown and increase amino acid availability. We studied whether glucocorticoid treatment influences the availability of amino acids, specifically those involved in the nitric oxide pathway. We prospectively studied 49 children with congenital heart disease undergoing cardiac surgery. Serum cortisol and amino acid levels were measured in arterial blood sampled before surgery (t=-5min), directly after surgery (t=0h) and at t=12h and t=24h after surgery. Serum cortisol and amino acid levels were compared between children who had received glucocorticoids (G+) and children who had not (G-). Of 49 patients included ((49% male, age 1.7 (0.5-8.7) y)), 33 (67%) received glucocorticoids. Baseline characteristics were not different between groups, except a higher weighted inotropic score in the G+ group. At t=0h, serum cortisol levels in the G+ group were significantly higher than in the G- group (7218 vs. 660nmol/L; (p<0.05)), but not different at the other time points. The levels of plasma amino acids had dropped after surgery. Compared to the G- group, in the G+ group the total amount of amino acids was significantly higher at t=12 and t=24; citrulline levels were higher at t=12 and t=24; and glutamine and arginine levels were higher at t=12. Glucocorticoid treatment during cardiac surgery in children preserves serum amino acid levels post-surgery. The preservation of glutamine, citrulline and arginine levels might have a beneficial effect on the related NO metabolism.