Harris-Benedict equation for critically ill patients: Are there differences with indirect calorimetry? Camila C. Japur MSc a, ⁎ , Fernanda R.O. Penaforte MSc a , Paula G. Chiarello PhD a , Jacqueline P. Monteiro PhD b , Marta N.C.M. Vieira PhD b , Anibal Basile-Filho PhD c a Departamento de Clínica Médica, Universidade de São Paulo, Brasil b Departamento de Pediatria e Puericultura, Universidade de São Paulo, Brasil c Departamento de Cirurgia e Anatomia Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brasil Keywords: Energy expenditure; Indirect calorimetry; Correction factors; Hypometabolism; Hypermetabolism Abstract Purpose: The aim of this study was to compare the measured energy expenditure (EE) and the estimated basal EE (BEE) in critically ill patients. Materials and Methods: Seventeen patients from an intensive care unit were randomly evaluated. Indirect calorimetry was performed to calculate patient's EE, and BEE was estimated by the Harris- Benedict formula. The metabolic state (EE/BEE × 100) was determined according to the following criteria: hypermetabolism, more than 130%; normal metabolism, between 90% and 130%; and hypometabolism, less than 90%. To determine the limits of agreement between EE and BEE, we performed a Bland-Altman analysis. Results: The average EE of patients was 6339 ± 1119 kJ/d. Two patients were hypermetabolic (11.8%), 4 were hypometabolic (23.5%), and 11 normometabolic (64.7%). Bland-Altman analysis showed a mean of -126 ± 2135 kJ/d for EE and BEE. Only one patient was outside the limits of agreement between the 2 methods (indirect calorimetry and Harris-Benedict). Conclusions: The calculation of energy needs can be done with the equation of Harris-Benedict associated with lower values of correction factors (approximately 10%) to avoid overfeeding, with constant monitoring of anthropometric and biochemical parameters to assess the nutritional changing and adjust the infusion of energy. © 2009 Elsevier Inc. All rights reserved. 1. Introduction Energy requirements estimation of healthy persons is a challenge for professionals because differences in real energy expenditure (EE) may occur even among persons of the same sex, age, weight, and height due to various genetic and environmental characteristics (ethnic origin, body composi- tion, diet, physical activity, environmental temperature, and altitude) [1]. For critically ill patients, these difficulties are even stronger because, in addition to all of those factors, there are influences of the disease itself and the effects of treatment, which may change oxygen consumption (VO 2 ) and/or carbon dioxide production (VCO 2 ) [2,3]. There are predictive equations used to estimate energy needs, asso- ciated to specific factors to correct the change in EE for each type of disease. Energy expenditure predictive equations may overestimate the energy needs up to 50% [4,5], probably ⁎ Corresponding author. E-mail address: camila@fmrp.usp.br (C.C. Japur). 0883-9441/$ – see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.jcrc.2008.12.007 Journal of Critical Care (2009) 24, 628.e1–628.e5