Effect of fluid overload on the prognosis of patients with acute kidney injury receiving continuous renal replacement therapy

Abstract

Objective To investigate the relationship between fluid overload(FO) and prognosis of critically ill patients with acute kidney injury (AKI) receiving continuous renal replacement therapy (CRRT), so as to provide a basis for the reasonable optimization of fluid management and improve the prognosis of critically ill patients with AKI. Methods We enrolled 261 adult AKI patients receiving CRRT who were admitted in ICU Department of the First Hospital of Jinlin University from January 2012 to June 2017. We retrospectively analyzed the clinical data of all enrolled patients and compared the clinical data between the survival group (n=149) and the death group (n=112). We screened and analyzed the risk factors of 30-day mortality after entering ICU of AKI critically ill patients receiving CRRT through multiple Logistic regression analysis. The Kaplan-Meier survival curve was used to compare the difference of 30-day mortality after entering ICU between the subgroups of fluid overload and non-fluid overload patients. Results ①The 30 day mortality was significantly higher in AKI patients receiving CRRT when the following situation existed: %FO total≥10%(OR=1.30, 95%CI:1.13-2.05, P=0.01), ventilator dependency(OR=1.65, 95%CI:1.01-2.55, P=0.03), oliguria(OR=1.55, 95%CI:1.13-2.15), SOFA≥13(OR=1.15, 95%CI:1.01-1.20, P 3 days (OR=1.03, 95%CI:1.01-1.13, P=0.04) and mean arterial pressure group 2> group 3> group > 4 (P<0.01).④The 30 day survival rate was significantly different between fluid overload patients(n=62) and non-fluid overload patients (n=92) in the septic group (P<0.01), while in the non-septic group the 30-day survival rate had no significant difference between fluid overload patients (n=31) and non-fluid overload patients (n=76) (P=0.291). The 30-day survival rate was significant different between fluid overload patients (n=57) and non-fluid overload patients (n=78) in the SOFA≥13 group (P=0.026), while in the SOFA<13 group the 30-day survival rate had no significant difference between fluid overload patients (n=35) and non-fluid overload patients (n=91) (P=0.074). Conclusions Fluid overload is closely associated with poor prognosis of critical ill patients with AKI. The removal of too much fluid through CRRT appears to reduce the mortality of severe AKI patients. The adverse effect of fluid overload on survival is more evident in AKI patients with sepsis or with more severe illness (SOFA≥13). Key words: Fluid overload; Acute kidney injury; Continuous renal replacement therapy; Prognosis