Critically ill patients experience a degree of hyperinflammation, cellular immune dysfunction, and oxidative stress. Supplementation with key nutrients, like glutamine and antioxidants, is most likely to have a favourable effect on these physiological parameters leading to an improvement in clinical outcomes. The results of two separate meta-analyses suggested that glutamine and antioxidants may be associated with improved survival. We have recently completed a dosing study to determine the maximal tolerable dose (MTD) of glutamine dipeptides and antioxidants in critically ill patients with evidence of hypoperfusion. The purpose of this protocol is to evaluate the effect of high dose glutamine and antioxidant supplementation on mortality in a large scale randomized trial.