Total parenteral nutrition and the patient with chronic obstructive pulmonary disease.

Patients with chronic obstructive pulmonary disease (COPD) are generally malnourished. A catabolic state predisposes these patients to infection and a subsequent increase in mortality. Nutritional support may be mandatory to prevent visceral deterioration, but side effects of total parenteral nutrition (TPN) feeding can be harmful to patients with COPD. The use of glucose concentrates causes an increase of CO2, creating a metabolic demand for O2 that usually cannot be met. Specific formulas of TPN for COPD patients, using lipids for calories and limiting glucose, lower the respiratory quotient. There still remains a dilemma for adequate nutritional repletion, however, because all nutrients alter respiratory demand. Patients in acute respiratory failure or those requiring mechanical ventilation create a vital challenge for the health care provider.