Indirect calorimetry in malnutrition: nutritional assessment or therapeutic reference?

The measurement of gas exchange for use in indirect calorimetry is a clinical research tool struggling to find its proper place in the care of acutely ill and nutritionally depleted patients. Some investigators have proposed that it should be used as part of the nutritional assessment. Unfortunately, in common with many other measurements for nutritional assessment, the information provided must be integrated with other information. It is recognized that factors other than malnutrition may influence the level of the metabolic rate. Despite the lack of precision and specificity, the measurement of energy expenditure provides an important reference for determining patients' requirements for energy intake. As with many other procedures in clinical medicine, the more severely ill the patient, the less the accuracy of standard formulas for estimating energy expenditure. Thus, actual measurements of energy expenditure assume special value.