Net ultrafiltration rate and its impact on mortality in patients with acute kidney injury receiving continuous renal replacement therapy

Abstract

Background Fluid overload, a critical consequence of acute kidney injury (AKI), is associated with worse outcomes. The optimal fluid removal rate per day during continuous renal replacement therapy (CRRT) is unknown. The purpose of this study is to evaluate the impact of the ultrafiltration rate on mortality in critically ill patients with AKI receiving CRRT. Methods This was a retrospective cohort study where we reviewed 1398 patients with AKI who received CRRT between December 2006 and November 2015 at the Mayo Clinic, Rochester, MN, USA. The net ultrafiltration rate (UFNET) was categorized into low- and high-intensity groups (<35 and ≥35 mL/kg/day, respectively). The impact of different UFNET intensities on 30-day mortality was assessed using logistic regression after adjusting for age, sex, body mass index, fluid balance from intensive care unit (ICU) admission to CRRT initiation, Acute Physiologic Assessment and Chronic Health Evaluation III and sequential organ failure assessment scores, baseline serum creatinine, ICU day at CRRT initiation, Charlson comorbidity index, CRRT duration and need of mechanical ventilation. Results The mean ± SD age was 62 ± 15 years, and 827 (59%) were male. There were 696 patients (49.7%) in the low- and 702 (50.2%) in the high-intensity group. Thirty-day mortality was 755 (54%). There were 420 (60%) deaths in the low-, and 335 (48%) in the high-intensity group (P < 0.001). UFNET ≥35 mL/kg/day remained independently associated with lower 30-day mortality (adjusted odds ratio = 0.47, 95% confidence interval 0.37–0.59; P < 0.001) compared with <35 mL/kg/day. Conclusions More intensive fluid removal, UFNET ≥35 mL/kg/day, among AKI patients receiving CRRT is associated with lower mortality. Future prospective studies are required to confirm this finding.

The Association of an Early Net Ultrafiltration Rate and 28-day Mortality in Patients Receiving Continuous Kidney Replacement Therapy: a Cohort Study

“…The results of this study were partly consistent with four previous studies [9][10][11][12]. Murugan and his colleagues found that in patients with volume overload > 5% and receiving renal replacement therapy, the 1-year mortality in patients with an NUF rate > 25 mL/kg/d was lower than that of < 20 mL/kg/d [9].…”

“…Murugan and his colleagues found that in patients with volume overload > 5% and receiving renal replacement therapy, the 1-year mortality in patients with an NUF rate > 25 mL/kg/d was lower than that of < 20 mL/kg/d [9]. Shahrzad found that in patients with AKI receiving CKRT, the NUF rate ≥ 35 mL/kg/d was associated with a lower 30-day mortality [10]. Two other studies found that, compared with an early NUF rate of < 1.01 mL/kg/h, an NUF rate of > 1.75 mL/kg/h was associated with increased mortality [11,12].…”

“…The NUF rate range commonly used in clinical practice is 0-10 mL/kg/h. Previous studies indicated that a low NUF rate (< 1.01 mL/kg/h) was associated with decreased survival [7,9,10]. A high NUF rate (> 1.75 mL/kg/h) was also related to increased mortality [7,11,12].…”

A Case Series: Continuous Kidney Replacement Therapy in Neonates With Low Body Weight

“…One previous study demonstrated that a higher net ultrafiltration rate was associated with a higher mortality rate ( 31 ). However, another study revealed an association between higher net ultrafiltration and improved survival rate ( 32 ). Similarly, the association between net ultrafiltration rate and renal recovery rate has yet to be established ( 33 ).…”

Prediction of Hemodynamic Tolerance of Intermittent Hemodialysis in Critically Ill Patients: A Cohort Study

“…The evaluation and management of uid balance are key challenges when caring for critically ill patients requiring renal replacement therapy (RRT) [1,2]. Despite considerable advances in the assessment of dialysis adequacy with respect to solute removal and data suggesting that net ultra ltration may be associated with the outcomes [3][4][5], there is currently no speci c measure of adequacy for uid removal [6,7]. Intradialytic hypotension is a common complication associated with RRT; it may be associated with the ultra ltration rate and can cause further ischemic injury to the recovering kidneys, thereby potentially reducing the probability of renal recovery [4,8].…”