Effects of hypercaloric feeding on nutrition status and carbon dioxide production in patients with long-term mechanical ventilation

Abstract

Background: To clarify clinical arguments regarding nutrition support in patients with long-term mechanical ventilation, we investigated the effects of hypercaloric feeding on nutrition status and carbon dioxide production.

Methods: Twenty-eight mechanically ventilated, clinically stable patients with nasogastric tube feeding were recruited and randomly divided into the control and hypercaloric groups, which were provided with 1.2- and 1.8-fold of resting energy expenditure (REE), respectively. The arterial and venous blood samples were collected, the anthropometric measurements were determined, the serum concentrations of nutrition-related proteins were measured, and the parameters on the ventilator and indirect calorimeter were recorded on weeks 0, 2, and 4.

Results: There were no significant changes in anthropometric measurements, blood gas tensions, and REE between the control and hypercaloric groups during the experimental period (mixed model with repeated measures analysis, p < .05). After adjusted for values on week 0 and time, patients with hypercaloric feeding had significantly increased levels in white blood cells, hemoglobin, and hematocrit. However, the control group had significantly decreased and the hypercaloric group had significantly increased serum concentrations of prealbumin and transferrin, rate of carbon dioxide production, and respiratory quotient (RQ) from week 0 to week 4.

Conclusion: Our results suggest that 4 weeks of hypercaloric feeding may significantly increase the production of carbon dioxide but may not significantly alter the clinical outcomes in patients with long-term mechanical ventilation. The adverse effects of hypercaloric feeding may easily be overlooked, and the appropriateness of nutrition support should be carefully monitored in patients with mechanical ventilation.