Total parenteral nutrition in critically ill surgical patients: fixed vs tailored caloric replacement

In critically ill patients accurate measurement of total energy expenditure (TEE) is possible by means of continuous indirect calorimetry. Since in many ICUs the necessary equipment is not available, the Harris-Benedict formula (HB) is frequently used to calculate TEE. Supplemental application of a clinical correction factor (HBc) has been advised. In this study we assessed the reliability of both methods of calculation and of a standard nutritional regimen, all three compared to the calorimetrically measured TEE (gold standard). Although the basic HB-formula did not perform better than the standard regimen, significantly better results were obtained by supplemental application of the clinical correction factor (HBc). It is left undecided, whether or not indirect calorimetry is actually to be preferred in daily clinical practice.