G. Briassoulis E. Briassouli T. Tavladaki S. Ilia D. M. Fitrolaki A. M. Spanaki Unpredictable combination of metabolic and feeding patterns in malnourished critically ill children: the malnutrition–energy assessment question Accepted: 21 September 2013 Published online: 17 October 2013 Ó Springer-Verlag Berlin Heidelberg and ESICM 2013 Presented in part at ESPNIC, Rotterdam, 14 June 2013. Dear Editor, Advances in paediatric critical care have resulted in the increased survival of chronically ill patients. In many units, such patients represent [ 50 % of the workload and are often mal- nourished [1]. Prediction of energy expenditure (PEE) equations are simple alternatives to the gold stan- dard of assessing resting energy expenditure (REE) by indirect calo- rimetry (IC). However, recent work has suggested that PEE equations fail to adequately predict REE. New paediatric intensive care unit (PICU)- oriented equations have been found to be no better than well-established tools, such as the Schofield-HW equation [2]. We have compared PICU-specialized and commonly used PEE equations with REE using a new modular metabolic monitor (E- COVX) in well-nourished and mal- nourished critically ill children. The E-COVX compact metabolic module has the advantage of not being influ- enced by uneventful open endotracheal suctioning [3]. It is suitable for repeated 30-min measurements in well-sedated mechanically ventilated children with stable respiratory patterns in a variety of ventilation modes [4]. We hypothesized that IC using the E-COVX would show that energy expenditure is unpredictable in mal- nourished children and that replacing REE with any PEE equation, includ- ing the new PICU-oriented equations, might not be applicable for estimating energy expenditure in patients suf- fering from malnutrition during a critical illness. The Ethics Committee of the Institutional Review Board approved this study, and parents or guardians of the children gave informed, written consent. Mechanically ventilated critically ill children, consecutively admitted to the PICU of the University Hospital, Heraklion, Crete, were enrolled in the study. Thirty consecutive 1-min gas exchange measurements (VO 2 and VCO 2 ) were taken and the respiratory quotient (RQ) and REE were calcu- lated for each patient (results were blinded from the attending physi- cian). The nutritional status was evaluated for the presence of protein- energy malnutrition as defined by Waterlow [5]. The PEE was esti- mated and basal metabolic rate (PBMR) was predicted using the common Harris–Benedict, Schofield– HW, Seashore, Fleisch, Caldwell– Kennedy and Henrys formulas, as well as equations specifically devel- oped for the PICU by White and by Meyer [2]. Patients were classified as hypermetabolic, normometabolic and hypometabolic when the REE was [ 110, 90–110 and \ 90 % of the Schofield–PBMR, respectively, and as overfed, adequately fed and underfed when the caloric intake was [ 110, 80–110 and \ 80 % of the REE, respectively. Forty-four patients (28 boys, 16 girls) were studied (total measure- ments 1,320). Four patients were admitted after an elective procedure; the remaining patients were admitted as a result of an acute illness or injury. Twelve (27.3 %) patients presented severe (4) or moderate (8) malnutrition. All patients survived. The REE did not differ between patients according to a body temper- ature of \ 37.1 °C (1,068 ± 460 kcal/ day) or C37.1 °C (824 ± 217 kcal/ day) or with a Ramsey sedation score of [ 3 versus B3 (956 vs. 915 kcal/ day). The mean differences between the non-malnourished and malnour- ished groups of patients were non- significant when calculated using the REE (178 ± 119 kcal/day, p \ 0.3), the White PEE equation (-80 ± 133 kcal/day, p \ 0.6), and the Meyer PEE equation (-171 ± 101 kcal/day, p \ 0.09). In contrast, the PEE calculated accord- ing to the Schofield–HW equation was lower in the malnutrition group (-251 ± 186 kcal/day, p \ 0.05), even though malnourished patients were fed more compared to the non- malnourished (399 ± 96 kcal/day, p \ 0.0001) (Fig. 1a). In the non-malnourished group, the Schofield equation was shown to overestimate REE compared to the two PICU-oriented PEE (p \ 0.0001). In the malnourished group, REE was lower than the PEE calculated using the Schofield-HW equation (p \ 0.0001), the White equation (p \ 0.02), and the Meyer equation (p \ 0.04) (Fig. 1a). Also, compared to the non-malnutrition group where energy intake was lower than REE (-256 ± 430 kcal/day, p \ 0.002), energy intake in the malnutrition group was higher than REE (301 ± 325 kcal/day, p \ 0.02). A contrasting combination of hypo-metabolism and over-feeding (79.8 ± 24 % vs. 145 ± 68 %, p = 0.0001) was demonstrated in the malnourished group of patients (Fig. 1b). Although new PICU-oriented PEE equations are the least likely to overestimate REE and therefore pre- ferred when REE cannot be Intensive Care Med (2014) 40:120–122 DOI 10.1007/s00134-013-3123-5 LETTER