Indirect calorimetry, indications, interpretation, and clinical application

Streszczenie

The aim of this review is to inform clinicians about the new possibilities in clinical nutrition (enteral or parenteral) based on indirect calorimetry. This method allows for the provision of an appropriate number of calories to undernourished hospitalized patients for nutritional repletion or maintenance. Providing too few or too many calories may result in adverse clinical consequences and worsen the course of the disease, especially in critically ill patients. Thus, optimizing nutrition support according to the individual and specific needs of patients is an urgent task. Indirect calorimetry (IC) is the only practical, clinical method to measure resting energy expenditure (REE). However, from a clinical perspective, knowledge of only one part of total energy expenditure (TEE) is insufficient to plan feeding that covers the actual energy needs of an individual patient. Currently, there is no method better than IC for accurately determining the resting energy needs of hospitalized patients. Although many predictive equations for REE have been developed, none of them can account for all the factors associated with changes in metabolism in critically ill patients. The most widely used equation for this purpose, the Harris and Benedict equation, was issued over 100 years ago and is inaccurate in about 40% of patients. To date, indirect calorimetry remains the gold standard for assessing REE. This paper addresses how to use and interpret indirect calorimetry in planning clinical nutrition for critically ill patients.