[Correlation of equations for energy expenditure with indirect calorimetry in critically ill patients]

Nutrition in the Intensive Care Unit (ICU) is a cornerstone; however, energy requirements are a controversial issue that has not yet been resolved. Calorimetry is the gold standard for calculating energy expenditure, but it is expensive and not available in all ICU areas. Formulas have been developed to calculate basal energy expenditure (BAE) and make the process easier.

To validate the predictive formulas of BAE compared to that obtained with ventilatory indirect calorimetry (IC) within the nutritional assessment in ICU patients.

Analytical cross-sectional retrolective study. We performed BAE measurement on patients in the ICU of a third level hospital with ventilatory indirect calorimetry and compared the results obtained with those of the Harris Benedict, Muffin-St. Jeor, Institute of Medicine, and Faisy equations.

A total of 49 patients were included; a moderate correlation with statistical significance was found between the BAE measurements obtained by indirect calorimetry, with those obtained by four predictive equations that were studied. The Faisy equation obtained the strongest correction with r = 0.461 (p = 0.001).

The correlation between the BAE obtained by predictive equations and by IC goes from mild to moderate, due to the heterogeneity of critical patients and their changing nature throughout their disease.