Association between calorie surplus and ICU length of stay in the critically ill: A retrospective cohort study.
Abstract
BACKGROUND & AIMS: Patients suffering persistent critical illness have poor short and long-term outcomes and consume disproportionate amounts of heath care resources. Nutritional optimisation may improve outcomes, though few data exist on resting energy expenditure and nutritional requirements. We hypothesised that increased calorie surplus per day is associated with increased ICU length of stay in the critically ill. METHODS: Patients from a single ICU at Royal London Hospital were included in this retrospective cohort study. EXPOSURE: Caloric surplus measured by indirect calorimetry and nutritional intake. INCLUSION CRITERIA: Mechanical ventilation ≥3 days, expected to remain ventilated. PRIMARY OUTCOME: ICU length of stay (LoS). Serial indirect calorimetry was performed alongside recording markers of critical illness and predicted requirements. RESULTS: Across 30 patients (median LoS 21 days), increased ICU LoS was associated with actual daily calorie intake surplus to REE (R2 0.16, p<0.005). Median REE was less than predicted energy requirements 24 kcal/day/kgIBW (IQR, 20-28) vs. 28 kcal/day/kgIBW (IQR, 26-29), p<0.001. Patients with COVID-19 had a median calorie surplus (actual intake - REE) +344kcal/day (IQR 35-517), vs. -57kcal/day (IQR-324-211) in other patients, p=0.011, however they had a median LoS 44 days (IQR 26-58) vs 10 days (IQR 7-24) respectively, p<0.001. Obese patients had a median calorie deficit -32kcal/day (IQR-384-335) vs. +234kcal/day (IQR-79-499) non-obese patients, p=0.021. There was no significant association between calorie surplus or deficit, and markers of overfeeding. CONCLUSION: Overfeeding represents an easily modifiable factor to improve outcomes in patients suffering from persistent critical illness, for which indirect calorimetry may be useful. This article is protected by copyright. All rights reserved.