Nutritionally associated increased carbon dioxide production. Excess total calories vs high proportion of carbohydrate calories.

This study compared carbon dioxide production (VCO2) from isocaloric nutritional regimens with varying concentration of carbohydrates with VCO2 from low and high caloric nutritional regimens with constant concentrations of carbohydrates (CHO) in 20 stable mechanically ventilated patients. Ten patients (group A) received total parental nutrition in the form of three isocaloric nutritional regimens; 40 percent CHO/40 percent fat/20 percent protein, 60 percent CHO/20 percent fat/20 percent protein, and 75 percent CHO/5 percent fat/20 percent protein. The VCO2 did not change with increasing CHO proportion; 205 +/- 35 ml/min, 203 +/- 25 ml/min, and 211 +/- 35 ml/min, respectively. Ten additional patients (group B) received three nutritional regimens at 1.0, 1.5, and 2.0 times the estimated resting expenditure with a 60 percent CHO/20 percent fat/20 percent protein proportion. The VCO2 increased with increasing total calories, 181 +/- 23 ml/min, 211 +/- 38 ml/min, and 244 +/- 40 ml/min (p less than 0.05). High caloric feeding increases VCO2 in contrast to high percentage carbohydrate formulation. Thus, moderate caloric intake appears to be more important in avoiding nutritionally related increases in VCO2 in stable mechanically ventilated patients.