Indirect calorimetry: applications in practice.

IC is the standard for determining energy expenditure in critically ill patients. The measured REE is an objective, patient-specific caloric reference that serves as the most accurate method of determining energy expenditure. Protocols addressing IC methodology are necessary to ensure technical accuracy and clinically useful results. The measured REE should be the caloric target without the addition of stress or activity factors for nutrition support regimens in the ICU. The RQ should be used primarily as an indicator of test validity. Optimal nutrition intervention requires continuous evaluation of all pertinent clinical data and careful monitoring of each patient's response to therapy.