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

Nina Inkinen,Renske Wiersema,Sakari Jukarainen,Suvi T Vaara,Ville Pettilä,Meri Poukkanen

doi:10.1016/j.jcrc.2021.05.002

Abstract

Whether positive fluid balance among patients with acute kidney injury (AKI) stems from decreased urine output, overzealous fluid administration, or both is poorly characterized. 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. 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. 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.

Highlights

Fluid therapy is one of the most common interventions in intensive care units (ICUs) all over the world
We found no association between cumulative fluid input, fluid output, and balance on day three and the day Acute kidney injury (AKI) developed (Supplemental Table S2)
In propensity score -matched, well-balanced cohort of 616 AKI and 616 non-AKI patients, we found AKI patients to both receive more fluids and have reduced fluid output, and have higher fluid balance compared to non-AKI patients on the third ICU day

Summary

Introduction

Fluid therapy is one of the most common interventions in intensive care units (ICUs) all over the world. Intravenous resuscitation fluid is given to critically ill patients mainly to restore intravascular volume [1], but considerable amounts of administered fluid are maintenance fluids and carrier fluids for drugs and nutrition [2]. Acute kidney injury (AKI) is one of the most significant disorders worsening the outcome of critically ill patients. It increases morbidity, mortality and costs [3,4,5,6,7,8]. Ensuring sufficient renal perfusion by preventing fluid deficit has conventionally been one of the cornerstones of AKI treatment [9,10,11]

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