Nutritional support in respiratory failure

Abstract

Malnutrition leads to lethal complications in the critically ill patient. The ramifications of generalized somatic muscle debility also affect the muscles of ventilation with sequelae of compromised ventilatory function. Visceral protein depletion retards immune competence and wound healing. The malnourished patient is predisposed to infection, prolonged intensive care stays, and increased morbidity and mortality. The application of nutritional support to patients with respiratory disease necessitates meticulous attentiveness to avoid clinical misadventure. A proper nutrition prescription requires an understanding of, as with any therapeutic intervention, its benefits, risks, and side effects. Each of the specific food substances, carbohydrate, fat, and protein, has its own influence on the respiratory quotient. The metabolism of each has particular effects on the respiratory system; nutrition itself may influence the work of breathing. Excess parenteral or enteral nutrition may produce severe complications. Deficiencies or excesses of specific ions, elements, or vitamins may be exacerbated. Enteral nutrition must be carefully timed and precisely formulated to prevent gastric atony and aspiration or diarrhea with electrolyte and acid base abnormalities. There are numerous methods of determining energy needs - some are estimates, others require sophisticated technology. This ability to monitor nutritional therapy allows for a level of precision in patient care heterofore unavailable to the health care team.