How a positive fluid balance develops in acute kidney injury: A binational, observational study

Kyle C White; Ary Serpa-Neto; Rod Hurford; Pierre Clement; Kevin B Laupland; Marlies Ostermann; Barnaby Sanderson; Michelle Gatton; Rinaldo Bellomo

doi:10.1016/j.jcrc.2024.154809

How a positive fluid balance develops in acute kidney injury: A binational, observational study

J Crit Care. 2024 Apr 11:154809. doi: 10.1016/j.jcrc.2024.154809. Online ahead of print.

Authors

Kyle C White¹, Ary Serpa-Neto², Rod Hurford³, Pierre Clement⁴, Kevin B Laupland⁵, Marlies Ostermann⁶, Barnaby Sanderson⁶, Michelle Gatton⁷, Rinaldo Bellomo⁸

Affiliations

¹ Intensive Care Unit, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia; Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia; Queensland University of Technology (QUT), Brisbane, Queensland, Australia. Electronic address: kyle.white@health.qld.gov.au.
² Australian and New Zealand Intensive Care Research Centre (ANZIC-RC), School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia; Department of Critical Care Medicine, Hospital Israelita Albert Einstein, São Paulo, Brazil.
³ Intensive Care Unit, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia.
⁴ Department of Intensive Care Services, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia.
⁵ Queensland University of Technology (QUT), Brisbane, Queensland, Australia; Department of Intensive Care Services, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia.
⁶ King's College London, Guy's & St Thomas' Hospital, Department of Critical Care, London, UK.
⁷ Queensland University of Technology (QUT), Brisbane, Queensland, Australia.
⁸ Department of Critical Care, University of Melbourne, Melbourne, Australia; Department of Intensive Care, Austin Hospital, Heidelberg, Australia; Department of Intensive Care, Royal Melbourne Hospital, Melbourne, Australia.

PMID: 38609773
DOI: 10.1016/j.jcrc.2024.154809

Abstract

Purpose: A positive fluid balance (FB) is associated with harm in intensive care unit (ICU) patients with acute kidney injury (AKI). We aimed to understand how a positive balance develops in such patients.

Methods: Multinational, retrospective cohort study of critically ill patients with AKI not requiring renal replacement therapy.

Results: AKI occurred at a median of two days after admission in 7894 (17.3%) patients. Cumulative FB became progressively positive, peaking on day three despite only 848 (10.7%) patients receiving fluid resuscitation in the ICU. In those three days, persistent crystalloid use (median:60.0 mL/h; IQR 28.9-89.2), nutritional intake (median:18.2 mL/h; IQR 0.0-45.9) and limited urine output (UO) (median:70.8 mL/h; IQR 49.0-96.7) contributed to a positive FB. Although UO increased each day, it failed to match input, with only 797 (10.1%) patients receiving diuretics in ICU. After adjustment, a positive FB four days after AKI diagnosis was associated with an increased risk of hospital mortality (OR 1.12;95% confidence intervals 1.05-1.19;p-value <0.001).

Conclusion: Among ICU patients with AKI, cumulative FB increased after diagnosis and was associated with an increased risk of mortality. Continued crystalloid administration, increased nutritional intake, limited UO, and minimal use of diuretics all contributed to positive FB.

Key points: Question How does a positive fluid balance develop in critically ill patients with acute kidney injury? Findings Cumulative FB increased after AKI diagnosis and was secondary to persistent crystalloid fluid administration, increasing nutritional fluid intake, and insufficient urine output. Despite the absence of resuscitation fluid and an increasing cumulative FB, there was persistently low diuretics use, ongoing crystalloid use, and a progressive escalation of nutritional fluid therapy. Meaning Current management results in fluid accumulation after diagnosis of AKI, as a result of ongoing crystalloid administration, increasing nutritional fluid, limited urine output and minimal diuretic use.

Keywords: Acute kidney injury; Creatinine; Critical illness; Diuretics; Fluid balance; Oliguria; Water-electrolyte imbalance.