The Use of Indirect Calorimetry in Nutrition Therapy and Its Impact on Clinical Outcomes in Critically ill Patients: A review

Adequate “nutritional support is an essential element for achieving favorable outcomes in critically ill patients, which requires an accurate evaluation of energy needs to avoid under or overfeeding.” Energy requirements of critically ill patients can be assessed either by Predictive equations (PEs) or by “indirect calorimetry(IC) measurements.” However, assessment of energy expenditure (EE) is a challenging task in intensive care unit patients” because EE during critical illness is widely variable and the current PEs are inaccurate to determine the caloric requirement in these patients.” Currently, IC is considered a gold standard for measuring EE as recommended by guidelines.” Despite being the most accurate method of measuring EE, adequate data are lacking to validate the beneficial effects of IC-guided nutrition therapy on clinical outcomes in critically ill patients. Because of this, the actual clinical benefits of IC are poorly appreciated, and it is still an underutilized tool among dietitians in clinical practice.” Therefore, in many centers, PEs are commonly used instead. The purpose of this review is to summarize the findings of recent studies regarding IC-guided nutrition therapy and its impact on clinical outcomes in critically ill patients.