A formula to calculate the standard liver volume in children and its application in pediatric liver transplantation

Due to a lack of available size-matched liver grafts from children, most pediatric recipients are transplanted with technical variant grafts from adult donors. Size requirements for these grafts are not well defined, and consequences of mismatched graft sizes in pediatric liver transplantation are not known. Existing formulas for calculation of a standard liver volume are mostly derived from adults disregarding the age-related percentual liver weight changes in children. In this study, we aimed to establish a formula for general use in children to calculate the standard liver volume. In a second step, the formula was applied in pediatric patients undergoing liver transplantation at our institution between 2000 and 2010 (n = 377). Analysis of a large number (n = 388) of autopsy data from children by regression analysis revealed a best fit for two formulas: "Formula 1," children 0 to ≤1 year (n = 246): standard liver volume [ml] = -143.062973 +4.274603051 * body length [cm] + 14.78817631 * body weight [kg]; "Formula 2," children >1 to <16 years (n = 142): standard liver volume [ml] = -20.2472281 + 3.339056437 * body length [cm] + 13.11312561 * body weight [kg]. In comparison with children receiving size-matched organs, we found an elevated risk of liver graft failure in children transplanted with a small-for-size graft, whereas large-for-size organs seem to have no negative impact.