Is measured energy expenditure correlated to injury severity score in major trauma patients?

A common method for calculating energy needs (PEE) in acute trauma patients is multiplying the Harris-Benedict equation (BEE) by activity factors (AF) and variable stress factors (SF) depending on the injury severity. Selection of the SF can be an arbitrary and potentially inaccurate decision. The purposes of this study were: (1) to investigate the relationship between injury severity score (ISS) to postinjury energy expenditure (MEE), and (2) to compare the MEE to PEE when using the SF of 1.75. Thirty-five severely injured patients (mean ISS = 27.5 +/- 10.7 SD) admitted to our Level I Trauma Center of the University of New Mexico were prospectively assessed for energy needs [PEE = BEE x 1.2(AF) x 1.75(SF)] and ISS. Total nutritional support delivered estimated needs. Indirect calorimetry measurements were obtained on all of the patients within the first 7-10 days following injury. No correlation (r = -0.042) existed between the MEE and ISS. There was a significant correlation (r = 0.772, P < 0.05) between PEE and MEE when using the SF of 1.75 for all of the patients. These results suggest that there is not a correlation between ISS and subsequent MEE in major trauma patients. In addition, using the SF of 1.75 will closely estimate energy needs in acute trauma patients.