MO837IMPACT OF DOWNTIME ON CLINICAL OUTCOMES IN CRITICALLY ILL PATIENTS WITH ACUTE KIDNEY INJURY RECEIVING CONTINUOUS RENAL REPLACEMENT THERAPY: A RETROSPECTIVE STUDY USING PROPENSITY SCORE-MATCHED ANALYSIS

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.