Search for a new dynamic formula to predict the liver volume: the energy expenditure model.

Abstract

Background: The assessment of liver volume (LV) is of paramount importance before surgical resection or transplantation to reduce the risk of postoperative hepatic insufficiency. It is usually measured with computed tomography and/or with some formulas, which are static methods. The aim of this study was to develop a new dynamic metabolic formula to predict the LV. Methods: Using computed tomography LV was calculated in 101 adult patients without liver diseases. LV was then correlated with the patients’ metabolic status calculated with the Harris-Benedict equation for the basal energy expenditure (BEE). The activity energy expenditure (AEE) was also calculated considering major surgery as an activity that require at least 10% more of BEE. Using linear regression analysis, a new formula was derived and was compared with the Heinmann, Urata, Emre, Vauthey, and Yoshizumi formulas. Results: A new basal formula was established: LV=0.789xBEE+272. It was found to be most accurate among those tested (R2=0.39, P<0.001). The model indicated that Heinmann’s, Emre’s, and Vauthey’s formulas overestimated the LV, while Urata’s and Yoshizumi’s formulas underestimated the LV. Similarly, a new activity formula was established: LV=0.789xAEE+272. Conclusion: The new formulas here derived give a dynamic perspective of the LV, which might be influenced by the actual patients’ metabolic status. Using the AEE is possible to estimate an increased value of LV, which may contribute to reduce the risk of postoperative hepatic insufficiency.