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<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.