Methods of assessing energy expenditure in the intensive care unit

An essential component in developing the nutrition support plan for hospitalized patients is evaluating energy requirements. Assessing energy expenditure (EE) and identifying requirements in the critically ill patient present the clinician with a challenge; how to prevent overfeeding and minimize underfeeding? Both under- and overfeeding have been associated with increased morbidity and mortality. It is known that critical illness alters EE. This alteration is hormonally mediated and is characterized by changes in metabolic processes. Methods used by clinicians to assess EE in the critically ill patient vary significantly. It is the purpose of this review to outline the various methods for evaluating EE in critical illness with emphasis on their benefits and limitations.