High fat, low carbohydrate, enteral feeding in patients weaning from the ventilator

To study whether high fat, low carbohydrate enteral nutrition could reduce $\dot VCO_2 $ in patients during ventilator support and weaning from the ventilator in order to facilitate the weaning process. Prospective, randomized controlled study. Medical ICU of a university hospital. 32 ventilator-dependent patients with a prospect of weaning from mechanical ventilation. High fat feeding administered to 15 patients and standard isocaloric feeding administered to 17 patients, both in a dosage of 1.5 times basal metabolic rate. Respiratory and metabolic measurements were obtained both during mechanical ventilation and weaning procedures. High fat feeding was associated with significantly lower RQ values compared with standard feeding; the mean (±SEM) RQ values during mechanical ventilation amounted to 0.91±0.01 and 1.00±0.02 and during weaning to 0.72±0.02 and 0.86±0.02 for high fat and standard nutrition respectively (bothp-values<0.001). High fat feeding reduced the CO₂-excretion both during mechanical ventilation and weaning, but only the decrease during weaning proved to be significant; the mean (±SEM) CO₂-excretion amounted to 0.177±0.010 and 0.231±0.011 l/min STPD for the high fat and standard feeding respectively (p<0.01). No significant differences were found in the PaCO₂ during weaning between the two feeding groups. High fat, low carbohydrate enteral feeding significantly reduced the RQ values in ventilated patients with decreases $\dot VCO_2 $ , but in this study failed to reduce PaCO₂ during weaning from the ventilator.