Affordable Access

Access to the full text

Positive fluid balance as an early biomarker for acute kidney injury: a prospective study in critically ill adult patients

  • Ávila, Maria Olinda Nogueira1, 2, 3
  • Rocha, Paulo Novis4
  • Perez, Caio A.5
  • Faustino, Tássia Nery3
  • Batista, Paulo Benigno Pena2, 6
  • Yu, Luis1
  • Zanetta, Dirce Maria T.7
  • Burdmann, Emmanuel A.1
  • 1 LIM 12, Disciplina de Nefrologia, Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, BR
  • 2 Monte Tabor Hospital Sao Rafael, Salvador, BA, BR
  • 3 Universidade do Estado da Bahia, Salvador, BA, BR
  • 4 Medicina Interna e Apoio Diagnostico, Universidade Federal da Bahia, Salvador, BA, BR
  • 5 Escola Bahiana de Medicina e Saude Publica, Salvador, BA, BR
  • 6 Faculdade de Medicina, Uniao Metropolitana de Educacao e Cultura UNIME/KROTON, Lauro de Freitas, BA, BR
  • 7 Departamento de Epidemiologia, Faculdade de Saude Publica, Universidade de Sao Paulo, Sao Paulo, SP, BR
Published Article
Faculdade de Medicina / USP
Publication Date
Feb 01, 2021
DOI: 10.6061/clinics/2021/e1924
PMID: 33567044
PMCID: PMC7847255
PubMed Central


OBJECTIVES: Positive fluid balance is frequent in critically ill patients and has been considered a potential biomarker for acute kidney injury (AKI). This study aimed to evaluate positive fluid balance as a biomarker for the early detection of AKI in critically ill patients. METHODS: This was a prospective cohort study. The sample was composed of patients ≥18 years old who stayed ≥3 days in an intensive care unit. Fluid balance, urinary output and serum creatinine were assessed daily. AKI was diagnosed by the Kidney Disease Improving Global Outcome criteria. RESULTS: The final cohort was composed of 233 patients. AKI occurred in 92 patients (40%) after a median of 3 (2-6) days following ICU admission. When fluid balance was assessed as a continuous variable, a 100-ml increase in fluid balance was independently associated with a 4% increase in the odds of AKI (OR 1.04; 95% CI 1.01-1.08). Positive fluid balance categorized using different thresholds was always significantly associated with subsequent detection of AKI. The mixed effects model showed that increased fluid balance preceded AKI by 4 to 6 days. CONCLUSION: These results suggest that a positive fluid balance might be an early biomarker for AKI development in critically ill patients.

Report this publication


Seen <100 times