Daily variability of resting energy expenditure in acute kidney injury patients on dialysis

Abstract Introduction: It is needed for nutrition prescription correct estimate of resting energy expenditure (REE), which is a challenge given the possible daily variation in critically ill patients with acute kidney injury (AKI). Objective: To evaluate the daily variability of REE measured by indirect calorimetry (IC) in patients with AKI and dialysis indication and identify clinical variables associated with REE. Methods: The REE was measured on the time of dialysis indication and the subsequent four days. We also evaluated parameters that can influence the REE. The daily differences were analyzed by generalized linear model for repeated measures. We also used Spearman correlation and multiple linear regression. Results: There were 301 IC measurements in 114 patients, mean age of 60.65 ± 16.9 years and 68.4% were male. The average REE was 2081 ± 645 kcal, rising on day 5 (2270 ± 556 kcal) compared to the days 2 and 3 (2022 ± 754; 2022 ± 660 kcal, respectively, p = 0,04). When normalized to weight, there was no significant difference in REE (kcal/kg/day) during follow-up. REE was positively correlated with total leukocyte count, C-reactive protein, minute volume (MV), fraction of inspired oxygen (FiO2) urea nitrogen appearance (UNA), weight and height and inversely with age. After multiple regression, MV, FiO2, weight and age are correlated independently with REE. Conclusion: Patients with AKI have REE stable. The REE was associated independently with FiO2, MV, body weight and age. Thus, ventilatory parameters should be evaluated each day for the necessary dietary changes may be made.