P0048 PP ENERGY REQUIREMENTS DURING ACUTE CRITICAL ILLNESS AND RECONVALESCENCE

Abstract

Introduction: Energy expenditure measurements enable adequate nutritional support of critically ill children. Assessment of resting energy expenditure (REE) by a metabolic monitor is useful in clinical practise, but may underestimate total daily energy expenditure (TDEE) as determined by the doubly labelled water (DLW) method. Aim of this study was to assess the relation between TDEE and REE during critical illness and reconvalescence in the first week after intensive care admission. Furthermore, we compared measured energy expenditure data with healthy controls. Methods: We enrolled 11 patients (0–16 yrs) with septicaemia (4), multitrauma (1) and following major thoracic/abdominal surgery (6). For one week, we measured TDEE with DLW. In the same period, we daily measured REE with a metabolic monitor. Measured TDEE and REE were compared to each other and to data of healthy controls (reference). All data are presented as mean±SD, energy data in MJ/day. Results: We performed 6±2 REE measurements per patient (respiratory quotient: 0.88±0.09). PRISM derived mortality risk was 10±9%. Rate constant (KH/KO) and dilution space (DH/DO) ratios for the DLW method were 0.85±0.03 and 1.03±0.01 respectively. REE of patients (3.10±1.92) and controls (3.01±1.60) was not different (95% CI: −0.17 to 0.35. TDEE of patients (3.89±2.31) and controls (3.78±1.86) was not different either (95% CI: −0.51 to 0.73). Measured TDEE was higher compared to measured REE (95% CI: 0.17 to 1.42) with a ratio REE/TDEE of 81±15%. REE explained 85% of the variance in TDEE. Conclusion: These acutely ill patients were not hypermetabolic compared to healthy controls. On average REE accounted for 81% of TDEE. This discrepancy between TDEE and REE is substantial and should be accounted for while planning nutritional support.