Early Fluid Balance Is Associated with 90-Day Mortality in Patients Receiving Continuous Renal Replacement Therapy

Continuous renal replacement therapy (CRRT) is widely used to control fluid balance, but the optimal fluid balance to improve the prognosis of patients remains debated. Appropriate fluid management may depend on hemodynamic status. We investigated the association between 90-day mortality and fluid balance/mean arterial pressure (MAP) in patients receiving CRRT. This single-center retrospective study was conducted between May 2018 and March 2021. Based on the cumulative fluid balance at 72 h after initiation of CRRT, the cases were divided into negative (< 0 mL) and positive (> 0 mL) fluid balance groups. Ninety-day mortality was higher in the positive fluid balance group (p=0.009). At 4 h before and after CRRT initiation, the mean MAP was lower in the positive fluid balance group (p<0.05). After multivariate cox adjustment, 72-h positive fluid balance was independently associated with 90-day mortality (p=0.004). In addition, the cumulative fluid balance was associated with 90-day mortality (p<0.05) in cases without shock, high APACHE II score, sepsis, dialysis dependence, or vasopressor use. A 72-h positive fluid balance was associated with 90-day mortality in patients receiving CRRT.