Estimating energy requirements in patients receiving parenteral nutrition
E. J. Quebbeman and R. K. Ausman
Adequate nutritional support should use a patient's energy expenditure as a
guide for administering sufficient but not excessive caloric intake.
Sixty-seven patients were evaluated using indirect calorimetry, to
determine the applicability of commonly used predictive equations for
energy expenditure in patients requiring parenteral nutrition. The
frequently used calculation that involves multiplying a constant value of
kilocalories per kilogram by the patients weight consistently
underestimated the energy requirements of patients of low body weight and
overestimated the requirements for heavy body weight. The Harris-Benedict
equation was found to be highly dependent on body weight and was not any
more accurate than estimations of individual requirements using a simpler
weight or surface area regression equation. We recommend that an actual
regression equation incorporating body weight or body surface area be used
to predict energy requirements and that the oversimplified but common use
of the constant value of kilocalories per kilogram be abandoned.
