The Research Of The Optimal Timing Of Continuous Renal Replacement Therapy In Patients With Septic Acute Kidney Injury

Objective Septic acute kidney injury (Septic AKI) is a common complication inthe intensive care unit(ICU).Studies have shown that, the mortality rate of ICU patientswith Septic AKI is over50%.Among these patients, who require renal replacementtreatment (RRT),the mortality rate is as high as80%.Although continuous renalreplacement therapy (CRRT) on Septic AKI has formed a consensus in the academic,the timing of CRRT is still a big controversy. In2012,the kidney disease improvingglobal outcomes(KDIGO) synthesized RIFLE and AKIN criteria, and formulated a newcriteria of diagnosis and staging about acute kidney injury (AKI).At present, the studies,which use2012KDIGO staging criteria for CRRT treatment timing to assess theprognosis of patients, are lacking. This research uses2012KDIGO staging criteria asthe CRRT treatment timing, in order to investigate the optimal timing of CRRT inSeptic AKI patients, and explores its mechanism.Methods This is a single-center retrospective study. We collect a total of118cases of patients admitted to surgical intensive care unit(SICU）of the Dalian MunicipalCentral Hospital affiliated to Dalian Medical University from March2009toDecember2012.The hospital information of these patients is complete, and conforms tothe2012KDIGO stage2and above at the same time. In these patients,57cases arestage2, and61cases are stage3.In the patients with stage2,27cases who receiveCRRT treatment are set for the stage2CRRT group. The rest of the30cases whoreceive conventional treatment are set for the stage2control group. In the patients withstage3,30cases beginning CRRT within48hours after AKI stage3are set for thestage3early CRRT group. The other31cases beginning CRRT after48hours are setfor the stage3late CRRT group. The collected information of these cases includespatients’ age, gender, weight, diagnosis, the site of infection, medical history and health status, mode of CRRT treatment, treatment dose, kinds of filter, etc. The monitoringindicators before and after48hours therapy, include nephrotoxin indexes (consist ofserum creatinine, serum urea nitrogen, and potassium), hemodynamic index (consists ofmean arterial pressure), tissue perfusion indexes (consist of oxygenation index andserum lactic acid level), multiple organ dysfunction syndrome (MODS) scores [consistof acute physiology and chronic health evaluation (APACHE Ⅱ) score and sequentialorgan failure assessment (SOFA) score],duration of mechanical ventilation and length ofICU stay. The major prognostic indicators of the4groups patients above are28-day and90-day mortality, the dependency rate of renal replacement therapy (RRT) in survivors.Results The main infected sites of the four groups patients’ are respiratory tractinfection and biliary tract infection. Nephrotoxin indexes: Values of serum creatinine,blood urea nitrogen and serum potassium, after48hours treatment, all of them in thethree groups of patients treated with CRRT improve obviously（P＜0.05）.Comparedwith the stage3late CRRT group, the nephrotoxin indexes of the stage3early CRRTgroup decrease significantly（P＜0.05）.Hemodynamic index: After48hours treatment,the four groups’ mean arterial pressure (MAP) are higher than before in different degree.Among them, MAP of the stage2control group, the stage2CRRT group and the stage3early CRRT group improve more obviously（P＜0.05）.Compared with the stage3lateCRRT group, MAP of the stage3early CRRT group rises obviously（P＜0.05）.Tissueperfusion indexes: Oxygenation index (OI) and serum lactic acid level, after48hourstreatment, both of them in the four groups are better than before in different degree.Among them, the indexes of the stage2control group,the stage2CRRT group and thestage3early CRRT group improve obviously（P＜0.05）.Compared with the stage3lateCRRT group, the tissue perfusion indexes of the stage3early CRRT group improveobviously（P＜0.05）.MODS score: APACHE Ⅱ score and SOFA score, after48hourstreatment, both of them in the stage2control group, the stage2CRRT group and thestage3early CRRT group are better than before. There is statistical significance（P＜0.05）.Duration of mechanical ventilation and length of ICU stay: Compared with its owncontrol group, both of them in the stage2CRRT group don’t change significantly.Compared with the stage3late CRRT group, both of them in the stage3early CRRTgroup reduce significantly （P＜0.05）.For the prognosis, the28-day mortality of thestage2control group is a little higher than that of stage2CRRT group, but there is nostatistical significance. The28-day mortality of the stage3late CRRT group issignificantly higher than that of stage3early CRRT group（P=0.030＜0.05）.The90-day mortality of stage2control group is a little higher than that of stage2CRRT group, butthere is no statistical significance. The90-day mortality of the stage3late CRRT groupis significantly higher than that of the stage3late CRRT group（P=0.029＜0.05）.Thecomparison of the28-day and90-day dependency rates of renal replacement therapy(RRT) in the4groups’ survivors: There is little difference between the stage2CRRTgroup and the stage2control group.The rates of the stage3late CRRT group are higherthan that of the stage3early CRRT group.Conclusion CRRT is an effective method for treatment of patients with SepticAKI. For the stage2patients with Septic AKI, CRRT treatment has little effect on theprognosis of patients. For the Septic AKI stage3patients, they need CRRT treatment assoon as possible(＜48hours). CRRT treatment can obviously reduce these patients’mortality-rate, and improve the prognosis.