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

OBJECTIVE

To study whether high fat, low carbohydrate enteral nutrition could reduce VCO2 in patients during ventilator support and weaning from the ventilator in order to facilitate the weaning process.

DESIGN

prospective, randomized controlled study.

SETTING

Medical ICU of a university hospital.

PATIENTS

32 ventilator-dependent patients with a prospect of weaning from mechanical ventilation.

INTERVENTIONS

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.

MEASUREMENTS AND RESULTS

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 (both p-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 1/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.

CONCLUSION

High fat, low carbohydrate enteral feeding significantly reduced the RQ values in ventilated patients with decreases in VCO2, but in this study failed to reduce PaCO2 during weaning from the ventilator.