Abstract: SA-OR106

Intensity of Ultrafiltration and Mortality in Critically Ill Patients with AKI and Fluid Overload

Session Information

  • What Happens After AKI
    November 04, 2017 | Location: Room 295, Morial Convention Center
    Abstract Time: 06:18 PM - 06:30 PM

Category: Acute Kidney Injury

  • 003 AKI: Clinical and Translational

Authors

  • Balakumar, Vikram, , University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Murugan, Raghavan M., University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Palevsky, Paul M., University of Pittsburgh, Pittsburgh, Pennsylvania, United States
  • Kellum, John A., University of Pittsburgh, Pittsburgh, Pennsylvania, United States
Background

We examined the association between ultrafiltration intensity and risk-adjusted one-year mortality among critically ill patients with fluid overload and receiving renal replacement therapy (RRT).

Methods

We analyzed a large intensive care unit (ICU) dataset involving adults admitted to a tertiary academic medical center over 8-year period. Acute kidney injury (AKI) was defined according to KDIGO criteria and only patients with AKI and fluid overload ≥ 5% of body weight prior to initiation of RRT were included. UF intensity was calculated as volume removed per day from initiation of either continuous or intermittent RRT until end of ICU stay adjusted for patient hospital admission body weight as follows: high >25ml/kg/day; moderate ≤25 - >20ml/kg/day, and low ≤20ml/kg/day. We constructed a propensity score to account for indication bias for UF intensity using age, sex, body mass index, race, surgery, baseline estimated GFR, first RRT modality, pre-RRT fluid balance, duration of RRT, time to RRT initiation as well as risk factors measured in the first 24 hours of ICU admission such as APACHE-III score, vasopressor use, mechanical ventilation use, suspected sepsis and severity of hypotension. We examined Kaplan-Meir failure plots in the propensity-matched cohort and fitted multivariable logistic regression for mortality.

Results

Of 1,075 patients with ≥5% fluid overload and receiving RRT, the distribution of high, moderate and low intensity UF were 40.4%(n=434), 15.2%(n=166) and 44.2%(n=475), respectively. The crude mortality was 59.4%, 60.2% and 69.7%, respectively. After combining low and moderate intensity groups (n=322) and propensity matching with high intensity group (n=322) in a 1:1 ratio, the high intensity UF groups had lower mortality compared with moderate and low intensity UF (56.5% vs. 70.2%, P<0.001). In the overall cohort, mortality was lower in high intensity UF group compared with low intensity UF (adjusted OR, 0.51, 95% CI, 0.35 - 0.73; P<0.001), whereas, there was no difference in mortality between moderate, compared with low intensity UF group (adjusted OR, 0.67; 95% CI, 0.42-1.05; P=0.08).

Conclusion

Higher intensity ultrafiltration of >25mls/kg/day compared with low intensity ultrafiltration of <20mls/kg/day is associated with lower one-year mortality in critically ill patients with fluid overload.