Fluid management in patients with acute kidney injury-A post-hoc analysis of the FINNAKI study

Purpose: Whether positive fluid balance among patients with acute kidney injury (AKI) stems from decreased urine output, overzealous fluid administration, or both is poorly characterized. Materials and methods: This was a post hoc analysis of the prospective multicenter observational Finnish Acute Kidney Injury study including 824 AKI and 1162 non-AKI critically ill patients. Results: We matched 616 AKI (diagnosed during the three first intensive care unit (ICU) days) and non-AKI patients using propensity score. During the three first ICU days, AKI patients received median [IQR] of 11.4 L [8.0-15.2]L fluids and non-AKI patients 10.2 L [7.5-13.7]L, p < 0.001 while the fluid output among AKI patients was 4.7 L [3.0-7.2]L and among non-AKI patients 5.8 L [4.1-8.0]L, p < 0.001. In AKI patients, the median [IQR] cumulative fluid balance was 2.5 L [-0.2-6.0]L compared to 0.9 L [-1.4-3.6]L among non-AKI patients, p < 0.001. Among the 824 AKI patients, smaller volumes of fluid input with a multivariable OR of 0.90 (0.88-0.93) and better fluid output (multivariable OR 1.12 (1.07-1.18)) associated with enhanced change of resolution of AKI. Conclusions: AKI patients received more fluids albeit having lower fluid output compared to matched critically ill non-AKI patients. Smaller volumes of fluid input and higher fluid output were associated with better AKI recovery. (c) 2021 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).