Impact of timing of renal replacement therapy initiation on outcome of septic acute kidney injury.

INTRODUCTION: Sepsis is the leading cause of acute kidney injury (AKI) in critical patients. The optimal timing of initiating renal replacement therapy (RRT) in septic AKI patients remains controversial. The objective of this study is to determine the impact of early or late initiation of RRT, as defined using the simplified RIFLE (risk, injury, failure, loss of kidney function, and end-stage renal failure) classification (sRIFLE), on hospital mortality among septic AKI patients. METHODS: Patient with sepsis and AKI requiring RRT in surgical intensive care units were enrolled between January 2002 and October 2009. The patients were divided into early (sRIFLE-0 or -Risk) or late (sRIFLE-Injury or -Failure) initiation of RRT by sRIFLE criteria. Cox proportional hazard ratios for in hospital mortality were determined to assess the impact of timing of RRT. RESULTS: Among the 370 patients, 192 (51.9%) underwent early RRT and 259 (70.0%) died during hospitalization. The mortality rate in early and late RRT groups were 70.8% and 69.7% respectively (P > 0.05). Early dialysis did not relate to hospital mortality by Cox proportional hazard model (P > 0.05). Patients with heart failure, male gender, higher admission creatinine, and operation were more likely to be in the late RRT group. Cox proportional hazard model, after adjustment with propensity score including all patients based on the probability of late RRT, showed early dialysis was not related to hospital mortality. Further model matched patients by 1:1 fashion according to each patient's propensity to late RRT showed no differences in hospital mortality according to head-to-head comparison of demographic data (P > 0.05). CONCLUSIONS: Use of sRIFLE classification as a marker poorly predicted the benefits of early or late RRT in the context of septic AKI. In the future, more physiologically meaningful markers with which to determine the optimal timing of RRT initiation should be identified.

Patients supported by extracorporeal membrane oxygenation and acute dialysis: acute physiology and chronic health evaluation score in predicting hospital mortality.

Extracorporeal membrane oxygenation (ECMO) can provide short-term cardiopulmonary support to critically ill patients. Among ECMO patients, acute renal failure requiring dialysis has an ominous prognosis. However, a prognostic scoring system and risk factors adjustment for hospital mortality in these patients have not been elucidated previously. A multicenter observational cohort study was conducted from January 2002 to December 2006. Information obtained included demographics, biochemical variables, Acute Physiology and Chronic Health Evaluation (APACHE) II, III, and IV scores at ICU admission and initial acute dialysis, and hospital mortality in 102 non-coronary artery bypass graft (CABG) patients receiving ECMO support with acute dialysis. This retrospective cohort study included 70 men and 32 women with a mean age of 47.9 ± 15.7 years. Seventy-two patients (70.6%) had hospital mortality. The area under the receiver operating characteristic curve showed APACHE IV (0.653) had a better discriminative power to predict hospital mortality than APACHE II (0.584) and APACHE III (0.634) at initializing dialysis. Hosmer-Lemeshow statistics showed good calibration for all three scores to predict hospital mortality at initializing dialysis (APACHE IV, P = 0.392; APACHE III, P = 0.094; and APACHE II, P = 0.673). Independent predictors for hospital mortality by multivariate logistic regression analysis were higher central venous pressure (odds ratio [OR], 1.11; confidence interval [CI] 95%, 1.02-1.20; P = 0.016), higher APACHE IV score at initializing dialysis (OR, 1.03; CI 95%, 1.01-1.05; P = 0.003), and latency from hospital admission to dialysis (OR, 1.04; CI 95%, 1.00-1.08; P = 0.033). High mortality rate was noted in non-CABG patients receiving ECMO and acute dialysis. Predialysis APACHE IV scores had good calibration and moderate discrimination in predicting hospital mortality in these patients. Because ECMO support could stabilize cardiopulmonary status, APACHE IV scores would likewise underestimate disease severity at lower score ranges in these patients.

Late initiation of renal replacement therapy is associated with worse outcomes in acute kidney injury after major abdominal surgery.

INTRODUCTION: Abdominal surgery is probably associated with more likelihood to cause acute kidney injury (AKI). The aim of this study was to evaluate whether early or late start of renal replacement therapy (RRT) defined by simplified RIFLE (sRIFLE) classification in AKI patients after major abdominal surgery will affect outcome. METHODS: A multicenter prospective observational study based on the NSARF (National Taiwan University Surgical ICU Associated Renal Failure) Study Group database. 98 patients (41 female, mean age 66.4 +/- 13.9 years) who underwent acute RRT according to local indications for post-major abdominal surgery AKI between 1 January, 2002 and 31 December, 2005 were enrolled The demographic data, comorbid diseases, types of surgery and RRT, as well as the indications for RRT were documented. The patients were divided into early dialysis (sRIFLE-0 or Risk) and late dialysis (LD, sRIFLE -Injury or Failure) groups. Then we measured and recorded patients' outcome including in-hospital mortality and RRT wean-off until 30 June, 2006. RESULTS: The in-hospital mortality was compared as endpoint. Fifty-seven patients (58.2%) died during hospitalization. LD (hazard ratio (HR) 1.846; P = 0.027), old age (HR 2.090; P = 0.010), cardiac failure (HR 4.620; P < 0.001), pre-RRT SOFA score (HR 1.152; P < 0.001) were independent indicators for in-hospital mortality. CONCLUSIONS: The findings of this study support earlier initiation of acute RRT, and also underscore the importance of predicting prognoses of major abdominal surgical patients with AKI by using RIFLE classification.