Fluid balance and mortality in critically ill patients with acute kidney injury: a multicenter prospective epidemiological study

Abstract Background and Aims Continuous renal replacement therapy (CRRT) is essential in treating critically ill patients with acute kidney injury, and circuit downtime is considered a quality indicator. However, it remains uncertain whether CRRT downtime affects outcomes such as mortality and renal recovery. This study investigated the impact of downtime on various clinical outcomes in critically ill patients undergoing CRRT. Method A total of 216 patients who underwent CRRT were retrospectively recruited. Downtime was calculated over 4 days from CRRT initiation, and patients were classified as downtime <20% or ≥20% of potential operative time. Patients with ≥20% downtime were matched to those with <20% downtime using 1:2 propensity score matching, adjusting for age, sex, comorbidity index, and severity score. Results There were 88 patients with <20% downtime and 44 patients with ≥20% downtime. The cumulative volume and median flow rate of effluent in patients with ≥20% downtime were lower than those in patients with <20% downtime (P<0.001 and 0.062, respectively). Daily fluid balance differed on days 2 and 3 (P=0.046 and 0.031, respectively), and the difference in levels of urea and creatinine widened over time (P=0.004 and <0.001, day 4). The levels of total carbon dioxide were lower in those with ≥20% downtime (P=0.038 and 0.020 at days 2 and 3). Based on our results, ≥20% downtime was not associated with increased 28-day mortality (P=0.944). On the other hand, a subgroup analysis showed the interaction between downtime and daily fluid balance on mortality (P=0.004). In this study, downtime was not related to renal recovery. Conclusion Increased downtime could impair fluid and uremic control and acidosis management in patients undergoing CRRT. Moreover, the adverse effect of downtime on fluid control may increase mortality rate. Further studies are needed to verify the value of downtime as a quality indicator and its impact on outcomes in critically ill patients requiring CRRT.

Download Full-text

Association between Latent Trajectories of Fluid Balance and Clinical Outcomes in Critically Ill Patients with Acute Kidney Injury: A Prospective Multicenter Observational Study

Kidney Diseases ◽

10.1159/000515533 ◽

2021 ◽

pp. 1-11

Author(s):

Meiping Wang ◽

Bo Zhu ◽

Li Jiang ◽

Xuying Luo ◽

Na Wang ◽

...

Keyword(s):

Acute Kidney Injury ◽

Logistic Regression ◽

Hospital Mortality ◽

Clinical Outcomes ◽

Critically Ill ◽

Fluid Balance ◽

Critically Ill Patients ◽

Kidney Injury ◽

Icu Mortality ◽

Increased Risk

Introduction: We aimed to identify different trajectories of fluid balance (FB) and investigate the effect of FB trajectories on clinical outcomes in intensive care unit (ICU) patients with acute kidney injury (AKI) and the dose-response association between fluid overload (FO) and mortality. Methods: We derived data from the Beijing Acute Kidney Injury Trial (BAKIT). A total of 1,529 critically ill patients with AKI were included. The primary outcome was 28-day mortality, and hospital mortality, ICU mortality and AKI stage were the secondary outcomes. A group-based trajectory model was used to identify the trajectory of FB during the first 7 days. Multivariable logistic regression was performed to examine the relationship between FB trajectories and clinical outcomes. A logistic regression model with restricted cubic splines was used to examine the dose relationship between FO and 28-day mortality. Results: Three distinct trajectories of FB were identified: low FB (1,316, 86.1%), decreasing FB (120, 7.8%), and high FB (93, 6.1%). Compared with low FB, high FB was associated with increased 28-day mortality (odds ratio [OR] 1.94, 95% confidence interval [CI] 1.17–3.19) and AKI stage (OR 2.04, 95% CI 1.23–3.37), whereas decreasing FB was associated with a reduction in 28-day mortality by approximately half (OR 0.53, 95% CI 0.32–0.87). Similar results were found for the outcomes of ICU mortality and hospital mortality. We observed a J-shaped relationship between maximum FO and 28-day mortality, with the lowest risk at a maximum FO of 2.8% L/kg. Conclusion: Different trajectories of FB in critically ill patients with AKI were associated with clinical outcomes. An FB above or below a certain range was associated with an increased risk of mortality. Further studies should explore this relationship and search for the optimal fluid management strategies for critically ill patients with AKI.

Download Full-text