Indirect calorimetry measurements in the ventilated critically ill patient: facts and controversies--the heat is on

The provision of nutrition to critically ill patients in the ICU often receives lower priority compared with hemodynamic and ventilation control. This frequently results in a significant calorie deficit. Overestimation of daily energy expenditure may also result in adverse outcomes. In many centers, nutritional decision making is based on predictive formulas, which have been shown to underestimate true energy requirements. Such estimations are ideally performed using indirect calorimetry. Nevertheless, the use of indirect calorimetry has been limited owing to costs and technical difficulties. Controversies about its actual clinical benefits are the focus of recent clinical studies and recommendations. The aim of this review was to describe the advantages of measuring indirect calorimetry within the concept of energy-protein goal-oriented therapy.