Low-dose continuous renal replacement therapy for acute kidney injury

Background: Continuous renal replacement therapy (CRRT) is used increasingly to treat acute kidney injury (AKI), which is a common condition in the intensive care unit (ICU). However, the optimal CRRT dose for the treatment of AKI is still a matter of controversy. This study was conducted to ascertain the minimal dose of CRRT that can be effective on AKI patient outcomes. Methods: This was a retrospective observational study in two ICUs of academic medical centers in Japan. Patients aged 15 years or older admitted to the ICUs from January 2007 to July 2010 and treated with CRRT for AKI during their ICU stay were included. Data were retrospectively collected from patient records. Patients were categorized by doses that were above (higher-dose group) or below (lower-dose group) the median. Major outcome measures were hospital mortality, ICU mortality, and renal recovery at hospital discharge. Results: 131 AKI patients were treated with continuous veno-venous hemodiafiltration (CVVHDF) during the study period. The median dose of CVVHDF was 16 ml/kg per hr (IQR = 14 to 20). Hospital mortality was 44%, which was significantly lower than the predicted mortality (56%, p<0.01). Patients who received lower-dose CRRT tend to have lower mortality rates (36% vs. higher-dose 53%; p = 0.055). Conclusions: We found that low-dose CRRT did not increase mortality in critically ill patients with AKI. We also found that AKI patients treated with lower-dose CRRT non-significantly but numerically lower hospital mortality compared to higher-dose CRRT.