The purpose of this randomized, double-blind study is to evaluate the utility of transitioning benzodiazepine sedation to dexmedetomidine in medical or surgical ICU patients requiring sedation when tracheal extubation is nearing.

This study is designed to determine the effect of administering parenteral glutamine dipeptide on rates of nosocomial infections and hospital mortality in patients requiring SICU care AND parenteral nutrition after cardiac, vascular or intestinal surgery. Consented patients are randomized to receive standard TPN or glutamine dipeptide-supplemented TPN.