# Nutrition in Pediatric Intensive Care: A Narrative Review
## 4 Optimal Energy and Protein Delivery for a Critically Ill Child  
The optimal energy delivery varies significantly over the PICU stay (lower E demands in the acute state, higher in the recovery state). A simple formula (such as 20-25 kcal/kg in the acute stage and 30-35 kcal/kg in recovery in adults) [4; 9; 30; 31] will not fit all age categories, as E demands per kilogram are higher in neonates and infants. The ideal method for the individualized E demand estimation is considered the indirect calorimetry (IC) [4; 18]. The availability of IC in PICUs is, however, still limited. In the case of IC's absence, the [PERSON], Food Agriculture Organization, World Health Organization (WHO) or United Nations University equations without additional risk factors can be used for optimal energy delivery calculation (see Table 1). [18], where the Schofield equation (age, gender, height and weight) is preferred by the ESPNIC [1]. Another recommended method for optimal/individualized E-target estimation is the volumetric measurement of VO\({}_{2}\) and/or VCO\({}_{2}\)[4; 12; 32]. The Harris-Benedict equation, which has been used for several decades, is not recommended in adult or pediatric intensive care anymore. Although not well-defined for the pediatric population, in the acute phase of adult critical illness, a hypocaloric target of 70% energy expenditure should be used [4]. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & & **Schofield Equation (kcal/Day)** & \\ \hline \multirow{4}{*}{\begin{tabular}{c} **VCO\({}_{2}\)** \\ **VCO\({}_{2}\)** \\ **VCO\({}_{3}\)** \\ **VCO\({}_{4}\)** \\ **VCO\({}_{5}\)** \\ **VCO\({}_{6}\)** \\ **VCO\({}_{7}\)** \\ **VCO\({}_{8}\)** \\ **VCO\({}_{9}\)** \\ **VCO\({}_{10}\)** \\ **VCO\({}_{11}\)** **VCO\({}_{12}\)** **VCO\({}_{13}\)** **VCO\({}_{14}\)** **VCO\({}_{15}\)** **V\({}_{16}\)** **V\({}_{17}\)** \\ \end{tabular} & \begin{tabular}{c} 569.59 \\ 958.59 \\ 950.03 \\ 1865.29 \\ \end{tabular} \\ \hline \multirow{4}{*}{\
\begin{tabular}{c} **VCO\({}_{2}\)** \\ **VCO\({}_{3}\)** \\ **VCO\({}_{4}\)** \\ **VCO\({}_{5}\)** \\ **VCO\({}_{6}\)** \\ **VCO\({}_{7}\)** \\ **VCO\({}_{8}\)** \\ **VCO\({}_{9}\)** \\ **VCO\({}_{10}\)** \\ **VCO\({}_{11}\)** **VCO\({}_{12}\)** **VCO\({}_{13}\)** **VCO\({}_{14}\)** **V\({}_{15}\)** **V\({}_{16}\)** **V\({}_{17}\)** \\ \end{tabular} &
\begin{tabular}{c} 567.58 \\ 888.56 \\ 1467.31 \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Energy delivery calculation equations with model examples. The aim of protein delivery is to avoid a negative protein balance (high risk in the early phase). For pediatric patients, the protein delivery should be minimally 1.5 g/kg/day (even higher in patients with respiratory failure and burns) [1; 18]. However, data confirming the positive influence of higher protein delivery (over 1.5 mg/kg/day) in the acute phase of critical illness on overall clinical outcome are currently missing [1; 18]. The protein (or amino acid) delivery should not exceed 3 g/kg/day or 2 g/kg/day in stable adolescents [33]. Despite insufficient data for pediatric patients, in adult patients, hypocaloric nutrition (not exceeding 70% of energy target) during the acute phase of critical illness with a progressive increase over 3 days up to 100% of the E target in the case of indirect calorimetry is used. On the contrary, if the energy need is estimated using predictive equations, hypocaloric nutrition is recommended (not exceeding 70% of calculated energy need) during the first week of critical illness [4]. In the acute phase, the protein E to nonprotein E ratio (defined by grams of nitrogen to nonprotein kcal ratio) should be higher (e.g., 1 gN:80 nonprotein kcal) compared to the late phase, where anabolic process prevails (ration 1 gN:130 or higher). The E and protein delivery aims for 66% (up to 100%) of calculated targets in the first seven days after PICU admission [18], preferentially by enteral route, if possible.