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Abstract: TH-OR16

Trajectories of Fluid Management after Initiation of Kidney Replacement Therapy in Critically Ill Patients: Insights from the STARRT-AKI Trial

Session Information

Category: Acute Kidney Injury

  • 101 AKI: Epidemiology, Risk Factors, and Prevention

Authors

  • Beaubien-Souligny, William, Centre Hospitalier de l'Universite de Montreal, Montreal, Quebec, Canada
  • Ghamarian, Ehsan, Applied Health Research Centre, Toronto, Ontario, Canada
  • Bagshaw, Sean M., University of Alberta, Edmonton, Alberta, Canada
  • Thorpe, Kevin, Applied Health Research Centre, Toronto, Ontario, Canada
  • Wald, Ron, St. Michael's hospital, Toronto, Ontario, Canada
Background

Fluid management is an essential component of renal replacement therapy (RRT) in critically ill patients. Both a positive cumulative fluid balance (CFB) and high net ultrafiltration (NUF) have been associated with adverse outcomes but fluid management trajectories remain incompletely described by previous efforts. We aimed to analyze the CFB/NUF as a trajectory over the first week after the initiation of RRT.

Methods

This is a secondary analysis using fluid balance data from individuals enrolled in the standard-strategy arm of the STARRT-AKI trial who initiated RRT. Cumulative fluid balance (CFB) since RRT initiation and daily net ultrafiltration (NUF) adjusted for body weight during the first 7 days after initiation of RRT were the main variables studied. We employed multivariable joint longitudinal models to determine the association with 90-day mortality. We then modeled the trajectory of fluid parameters using spline functions and used latent class analysis methods to identify predominant trajectories to compare patients’ characteristics and outcomes.

Results

We included 855 patients in the analysis. After adjustments, an association between CFB and 90-day mortality was found (HR: 1.075 (1.04; 1.11) p<0.001) but no association with net daily NUF (HR: 0.95 (CI: 0.64; 1.39) p=0.78). Using latent class analysis, we identified two distinct CFB/NUF trajectories. Class A was characterized by a slight increase in CFB and low/stable NUF after RRT initiation while class B was characterized by an increasingly negative CFB with initially higher daily NUF during the first 4 days followed by a stabilization after day 4. In adjusted analysis, individuals classified in class A were at higher risk for 90-day mortality (aOR: 2.22 CI: 1.52; 3.28) p<0.001) compared to class B.

Conclusion

Beyond cumulative fluid balance and daily NUF rate, the overarching CFB/NUF trajectory should be considered when attempting to elucidate the safety of fluid balance management strategies.

Predominant trajectories of A) cumulative fluid balance (CFB) in mL/kg and B) daily ultrafiltration rate (UF) in mL/kg/d.