Metabolic and respiratory effects of enteral nutrition in patients during mechanical ventilation

Abstract

The effect of enteral feeding on O2-consumption ( {Mathematical expression}) and CO2-production ( {Mathematical expression}) was studied in 9 ventilator-dependent patients, who were in a stable condition without signs of hypermetabolism. Resting energy expenditure (REE) in postabsorptive state was assessed and enteral feeding was started by continuous drip (480 kcal carbohydrate, 360 kcal vegetable fat and 160 kcal milkprotein: 6.4 g Nitrogen/ 1000 ml). Patients were given a moderate and a high caloric intake: 1.5 and 2.0 times REE. {Mathematical expression} and {Mathematical expression} were measured for a 24 h period, beginning 7 h after the start of the dietary intake. Significant greater increases in {Mathematical expression}, {Mathematical expression} and RQ were found during high caloric intake compared with the moderate caloric intake. {Mathematical expression}, {Mathematical expression} and arterial blood-gases were measured in 4 patients during weaning from the ventilator. The increase in {Mathematical expression} induced by the high caloric feeding resulted in a rise in arterial CO2 tension (PaCO2) and respiratory distress. High caloric enteral nutrition can cause a significant increase in {Mathematical expression} inducing respiratory distress during weaning from the ventilator in patients with limited pulmonary reserves. Moderate caloric nutrition will be preferable to these patients in order to facilitate the weaning. © 1988 Springer-Verlag.