Prediction of Resting Energy Expenditure in Children: May Artificial Neural Networks Improve Our Accuracy?

The inaccuracy of resting energy expenditure (REE) prediction formulae to calculate energy metabolism in children may lead to either under- or overestimated real caloric needs with clinical consequences. The aim of this paper was to apply artificial neural networks algorithms (ANNs) to REE prediction. We enrolled 561 healthy children (2-17 years). Nutritional status was classified according to World Health Organization (WHO) criteria, and 113 were obese. REE was measured using indirect calorimetry and estimated with WHO, Harris-Benedict, Schofield, and Oxford formulae. The ANNs considered specific anthropometric data to model REE. The mean absolute error (mean \ub1 SD) of the prediction was 95.8 \ub1 80.8 and was strongly correlated with REE values (R2 = 0.88). The performance of ANNs was higher in the subgroup of obese children (101 \ub1 91.8) with a lower grade of imprecision (5.4%). ANNs as a novel approach may give valuable information regarding energy requirements and weight management in children

Resting Energy Expenditure assessment in mechanically ventilated critically ill children: the importance of Indirect Calorimetry

Introduction. Malnutrition is common in critically ill children, and is considered a negative prognostic factor for their clinical outcomes1,2. Traditionally, Resting Energy Expenditure (REE) is calculated using predictive equations. These equations might be inaccurate in the critical scenario. Indirect Calorimetry (IC) is the gold standard to measure REE and allows tailored nutrition support3 . Aim of the study was to evaluate the accuracy of commonly employed equations as compared to IC-derived values in critically ill children. Methods. Children admitted to our unit between January 2017 and March 2019, aged <18 years and mechanically ventilated were enrolled. Endotracheal tube leak >10% and/or a fraction of inspired oxygen 650.6 constituted exclusion criteria. Harris-Benedict, Schofield and WHO formulae were applied to estimate REE. We performed IC for 30 minutes and REE was measured. The agreement between IC- and equation-based values of REE was assessed via paired t-test and BlandAltman analysis. Data are expressed as mean and standard deviation. Statistical significance was defined as p<0.05. Results. Forty-four critically ill children (4.3\ub14.2 years, 18.1\ub116.4 kg) admitted for acute respiratory failure (n=24), neurological (n=13) or other diseases (n=7) were studied. Measured REE ranged between 16 and 89 kcal/kg/die (mean 43\ub115). Typically, all formulae significantly over-estimated the REE, as compared to IC (Table 1). Furthermore, the Bland-Altman analysis revealed wide limits of agreement, suggesting low accuracy of the prediction equations. Conclusions. In critically ill, mechanically ventilated patients REE is on average significantly lower than predicted by currently applied equations. This finding might be explained by a reduced work of breathing and/or the use of sedatives and paralyzing agents. Measurement of REE through IC is essential to avoid over/underfeeding in this population. References 1. Agostoni C et al. JPGN 2016 2. Taku Oshima et al. Clinical Nutr 2017 3. Smallwood CD et al. J Pediatr. 201

Gas-exchange and resting energy expenditure measurement with indirect calorimetry in children supported with non-invasive ventilation

Introduction. Nutrition plays a fundamental role in critically ill children and personalized nutritional therapy requires the measurement of resting energy expenditure (REE) [1-2]. Indirect calorimetry (IC) is the gold standard for REE assessment and is based on V\ue22fO2 and V\ue22fCO2 measurements. Furthermore, IC provides information on carbohydrates/lipids consumption by defining the respiratory quotient (RQ). However, while IC is validated for spontaneously breathing and mechanically ventilated patients, it is not for patients undergoing non-invasive ventilation (NIV) [3]. Aim of the study is therefore to validate IC for children undergoing NIV by comparing IC results obtained during spontaneous breathing with data gathered during NIV-CPAP (continuous positive airway pressure). Methods. Patients (age <6 years) admitted to our pediatric intensive care unit (PICU) and weaning from NIV-CPAP were enrolled. Two IC measurements (Canopy mode) were performed for 20 minutes in randomized order in the following conditions: 1) Spontaneous breathing (SB), 2) NIV-CPAP (performed by single-limb circuit and vented mask). Average values for V\ue22fCO2 , V\ue22fO2, RQ and REE were obtained in the two conditions. Comparison between groups was performed via paired t-test. Agreement was assessed via Bland-Altman analysis. Statistical significance was defined as p<0.05. Results. Four patients (median age 8 months, median weight 8 kg) were enrolled. V\ue22fCO2 , V\ue22fO2, RQ and REE did not differ significantly between groups. Limits of agreement (LOA) and BIAS indicate a good agreement between the two measures (Table 1). Conclusions. Our preliminary data suggest that IC can be accurately performed in children undergoing NIV using a single limb circuit with intentional leaks. These results need to be confirmed on a broader cohort of critically ill children. References 1. De Cosmi V et al. Nutrients. 2017, 18:9 2. Mehta NM et al. Pediatr Crit Care Med. 2017, 18:675-715 3. Taku Oshima et al. Clinical Nutr 2017; 36:651-66

Fluid therapy in mechanically ventilated critically ill children: the sodium, chloride and water burden of fluid creep

Background: Fluid therapy is a cornerstone of pediatric intensive care medicine. We aimed at quantifying the load of water, sodium and chloride due to different fluid indications in our pediatric intensive care unit (PICU). We were particularly interested in the role of fluid creep, i.e. fluid administered mainly as the vehicle for drugs, and the association between sodium load and water balance. Methods: Critically ill children aged 643 years and invasively ventilated for 6548 h between 2016 and 2019 in a single tertiary center PICU were retrospectively enrolled. Need for renal replacement therapy, plasmapheresis or parenteral nutrition constituted exclusion criteria. Quantity, quality and indication of fluids administered intravenously or enterally, urinary output and fluid balance were recorded for the first 48 h following intubation. Concentrations of sodium and chloride provided by the manufacturers were used to compute the electrolyte load. Results: Forty-three patients (median 7 months (IQR 3-15)) were enrolled. Patients received 1004 \ub1 284 ml of water daily (153 \ub1 36 ml/kg/day), mainly due to enteral (39%), creep (34%) and maintenance (24%) fluids. Patients received 14.4 \ub1 4.8 mEq/kg/day of sodium and 13.6 \ub1 4.7 mEq/kg/day of chloride, respectively. The majority of sodium and chloride derived from fluid creep (56 and 58%). Daily fluid balance was 417 \ub1 221 ml (64 \ub1 30 ml/kg/day) and was associated with total sodium intake (r2 = 0.49, p < 0.001). Conclusions: Critically ill children are exposed, especially in the acute phase, to extremely high loads of water, sodium and chloride, possibly contributing to edema development. Fluid creep is quantitatively the most relevant fluid in the PICU and future research efforts should address this topic in order to reduce the inadvertent water and electrolyte burden and improve the quality of care of critically ill children