Evaluation Of The Optimal Timing Of Continuous Renal Replacement Therapy For Critically Ill Patients With Acute Kidney Injury

Objectives: Acute kidney injury(AKI) is a common and serious complication in critically ill patients.Continuous renal replacement therapy(CRRT) has become an important part of the treatment in critical care and is considered an established treatment modality for critically ill patients with AKI. However, the optimal timing for initiating CRRT remains controversial.This study was aimed to evaluate the optimal timing for CRRT initiation by observing the relevant parameters before CRRT and the value of these parameters for the prediction of 28-day mortality rate in critically ill patients with AKI.Methods: A retrospective analysis was performed on the date of patients who received CRRT for AKI and the clinical data were complete. All patients were enrolled from Intensive Care Unit(ICU) and Emergency Intensive Care Unit(EICU) in the Second Afiliated Hospital of Dalian Medical University during January 2013 to January2015. These patients were diagnosed as AKI according to the Kidney Disease Improving Global Outcomes(KDIGO) guidelines and treated with continuous veno-venous hemofiltration(CVVH). The 28 th day after CRRT initiation was regared as the end of observation.According to the clinical outcomes,these patients were divided into survivor and death groups.Before initiating CRRT, the basic clinical data and laboratory parameters of the two groups were collected.The two groups were compared using the independent t test for continuous variables and using chi-square test forcategorical variables. We drew receiver operating characteristic(ROC) cures to compare these parameters of initiating CRRT,which were statistically significant difference in two groups and observed their predictive value of 28-day mortality rate in patients.The area under the curve(AUC) and these parameters of diagnostic cut-off value was calculated. The cumulative survival curves of 28-day were designed using the Kaplan Meier method and compared using the log-rank test.Results:1.79 critically ill patients with AKI were enrolled in this study.The mean age of the patients was 60.58±19.75 years old. The most common cause of AKI was pre-renal factors(53.16%), followed by infection(41.77%).However, there were no statistically significant difference between the two groups in etiology(P >0.05).2. Followed up to 28-day after initiating CRRT,there were 29 patients in survivor group and 50 patients in death group, these patients 28-day mortality rate was63.29%.41 patients died during in-hospital period,the in-hospital mortality rate was51.90%. In hospitalized patients AKI combined with shock(39.02%),multiple organ dysfunction syndrome(MODS)(26.83%) was the main dead causes.3.Five parameters of the two groups including intervals from ICU admission to CRRT start, the bicarbonate, pH, red blood cell distribution width(RDW), mean platelet volume(MPV) before CRRT initiation by univariate analysis, showed that there were statistically significant difference(P<0.05). We drew receiver operating characteristic(ROC) cures of these parameters and calculated the AUC, showed that the time interval from admission to ICU to the initiation of CRRT, RDW and MPV level before CRRT initiation,which had the predictive value of 28-day mortality rate in patients. The AUCs of the three parameters were 0.698, 0.663, and 0.665 respectively.The diagnostic cut-off values were 3 days, 13.75%, and 10.15 fL respectively.4.According to the seven indicators of diagnostic cut-off value, including intervals from ICU admission to CRRT start, RDW, MPV, intervals+RDW,intervals+MPV, RDW+MPV, intervals+ RDW+MPV, the patients were divided into the early and late groups, showed that the 28-day mortality rate in the early group was significantly lower than the late group(P< 0.05).Drawing the cumulative survivalcurves of 28-day in early and late groups using the Kaplan Meier method, showed that the cumulative survival rate of 28-day in the early group was significantly higher than the late group(P< 0.05).Conclusions:1.Intervals from ICU admission to CRRT start(3days), RDW(13.75%)and MPV(10.15fL) level before CRRT initiation can be used as indicators to evaluate the optimal timing for initiating CRRT.These three parameters are useful in predicting28-day mortality rate in critically ill patients with acute kidney injury.2.Early initiating CRRT may improve the survival rate of 28-day in critically ill patients with acute kidney injury.