Despite strict hand washing, sterile technique, and antibiotic-coated catheters, nosocomial infection and sepsis remain the leading acquired causes of morbidity and mortality in critically ill children. Subsequent use of antibiotics to treat nosocomial infection and sepsis is considered a major attributable factor in the rise of antibiotic-resistant organisms in this population of children. Presently, "prophylaxis" strategies are used to prevent stress-induced gastrointestinal bleeding; however, no "prophylaxis" strategy is used to prevent stress-induced nosocomial infection and sepsis. When left unopposed, the stress hormone, cortisol, induces lymphocyte apoptosis, lymphopenia, and immune insufficiency. Prolactin is the counter-regulatory stress hormone that prevents cortisol-induced apoptosis and immunosuppression. Zinc, selenium, and glutamine are also important in maintenance of lymphocyte health. Critically ill patients commonly develop hypoprolactinemia secondary to increased central nervous system dopaminergic activity, as well as zinc, selenium, and glutamine deficiency caused by increased utilization and decreased supply. Hypoprolactinemia can be prevented by metoclopramide, a dopamine 2 receptor antagonist commonly used as a prokinetic in children, and zinc, selenium, and glutamine deficiency can be prevented with enteral supplementation. This study will use a double-blind randomized controlled trial design to test the hypothesis that daily prophylaxis with metoclopramide, zinc, selenium and glutamine will reduce nosocomial infection and sepsis in critically ill children.