Glutamine administration in patients undergoing cardiac surgery and the influence on blood glutathione levels

Cardiac surgery with an extracorporeal circulation cardiopulmonary bypass (CPB) is characterized by an oxidative stress response. Glutathione (GSH) belongs to the major antioxidative defense. In metabolic stress, glutamine (GLN) may be the rate-limiting factor of GSH synthesis. Decreased GLN plasma levels were observed after various critical states. We evaluated, in patients undergoing open heart surgery with CPB, the effects of a peri-operative GLN supplementation on GSH in whole blood and assessed their influence on the Sequential Organ Failure Assessment score and the intensive care unit length of stay.

In this prospective, randomized, double-blinded study, we included 60 patients (age older than 70 years, ejection fraction <40% or mitral valve replacement) undergoing an elective cardiac surgery with CPB. We randomly assigned each subject to receive an infusion with either GLN (0.5 g/kg/day, group 1) or an isonitrogeneous, isocaloric, isovolemic amino acids solution (group 2) or saline (group 3).

From the first post-operative day GLN plasma levels in group 1 were significantly increased compared with the other groups. With saline GSH the levels decreased significantly post-operatively compared with GLN. We observed a significant correlation between GLN delivery and GSH levels.

A peri-operative high-dose GLN infusion increased plasma GLN concentrations and maintained the GSH levels after cardiac surgery with CPB.