Indirect calorimetry: should it be part of routine care or only used in specific situations?

Indirect calorimetry (IC) is increasingly recommended to guide energy delivery in the ICU. This review aims to provide a critical overview of current literature in support of these recommendations. There is insufficient evidence to ascertain a mortality benefit from IC-guided energy delivery. However, large variations in energy expenditure during critical illness pose a risk for significant under- and overfeeding if IC is not routinely used. Even in the absence of demonstrable clinical benefits, there is a strong physiological rationale in favor of performing IC. Measurements can be prioritized in complex patients and should be repeated during prolonged ICU stay.