***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    ***EXAMPLES*** 
    Input: BACKGROUND Despite the widespread use of continuous renal replacement therapy in critically ill patients with acute renal failure ( ARF ) , there are few data supporting its benefits over conventional intermittent hemodialysis ( IHD ) . We sought to analyze differences in survival between modalities in a study that compared continuous venovenous hemodialysis ( CVVHD ) with IHD . METHODS Eighty critically ill patients with ARF requiring dialysis were r and omized after stratification by severity of illness to treatment with CVVHD or IHD .  RESULTS There were no differences in survival or renal recovery between groups . In patients who died , mean survival time was 10.7 + /- 11.2 days for the IHD group versus 14.3 + /- 16.1 days for the CVVHD group ( P = not significant ) . There was greater net volume removal in the CVVHD group during 72 hours . Declines in urine output during 72 hours were similar between groups . Mean arterial pressure off and on dialysis therapy was analyzed retrospectively . There was a significant decrease in mean arterial pressure for patients on IHD therapy not seen in those on CVVHD therapy , but this did not lead to a survival advantage . CONCLUSION Despite greater volume control , CVVHD did not lead to an improvement in survival , preservation of urine output , or renal recovery compared with IHD in patients with ARF Among critically ill patients , acute kidney injury ( AKI ) requiring dialysis is associated with mortality rates generally in excess of 50 % . Continuous renal replacement therapies ( CRRT ) often are recommended and widely used , although data to support its superiority over intermittent hemodialysis ( IHD ) are lacking . Data from the Program to Improve Care in Acute Renal Disease ( PICARD ) , a multicenter observational study of AKI , were analyzed . Among 398 patients who required dialysis  , the risk for death within 60 d was examined by assigned initial dialysis modality ( CRRT [ n = 206 ] versus IHD [ n = 192 ] ) using st and ard Kaplan-Meier product limit estimates , proportional hazards ( " Cox " ) regression methods , and a propensity score approach to account for selection effects . Crude survival rates were lower for patients who were treated with CRRT than IHD ( survival at 30 d 45 versus 58 % ; P = 0.006 ) . Adjusted for age , hepatic failure , sepsis , thrombocytopenia , blood urea nitrogen , and serum creatinine and stratified by site , the relative risk for death associated with CRRT was 1.82 ( 95 % confidence interval 1.26 to 2.62 ) . Further adjustment for the propensity score did not material ly alter the association ( relative risk 1.92 ; 95 % confidence interval 1.28 to 2.89 ) . Among critically ill patients with AKI , CRRT was associated with increased mortality . Although the results could reflect residual confounding by severity of illness , these data provide no evidence for a survival benefit afforded by CRRT . Larger , prospect i ve , r and omized clinical trials to compare CRRT and IHD in severe AKI are needed The syndrome of sepsis-associated severe acute renal failure is a frequent component of sepsis-induced multiorgan failure . Continuous hemofiltration techniques are often used in its dialytic management but little is known about their impact . The aim of this study is to define the biochemical and clinical impact of continuous hemodiafiltration ( CHD ) in the management of this syndrome and to retrospectively compare it to that of conventional dialysis . A prospect i ve , cohort study and retrospective comparison with historical controls was conducted at an intensive care unit ( ICU ) of a tertiary institution . Eighty-seven consecutive septic patients with acute renal failure were treated by continuous hemodiafiltration and 40 consecutive similar patients by conventional dialysis .  All new cases of severe acute renal failure with sepsis were treated by means of continuous hemodiafiltration . Historical controls were treated by means of conventional dialysis . Illness and sepsis severity were assessed on admission and prior to initiation of treatment . Biochemical variables were assessed daily . Outcome was measured as discharge from the ICU , duration of oliguria and discharge from hospital . Of the 87 patients treated by hemodiafiltration , 86 had multiorgan failure , 71 ( 81.6 % ) septic shock and 52 ( 59.8 % ) bacteremia/fungemia . Their APACHE II score on admission was 29.9 and their mean organ failure score prior to treatment was 4.3 . Hemodiafiltration result ed in a significant fall in mean urea and creatinine levels within 24 h and in the correction of acidosis . The mean alveolar-arterial gradient fell from 276 to 211 mm Hg ( p < 0.02 ) within 24 h of therapy . Complications were few and mostly related to vascular access . ( ABSTRACT TRUNCATED AT 250 WORDS BACKGROUND Acute renal failure ( ARF ) requiring dialysis in critically ill patients is associated with an in-hospital mortality rate of 50 to 80 % . The worldwide st and ard for renal replacement therapy is intermittent hemodialysis ( IHD ) . Continuous hemodialysis and hemofiltration techniques have recently emerged as alternative modalities . These two therapies have not been directly compared . METHODS A multicenter , r and omized , controlled trial was conducted comparing two dialysis modalities ( IHD vs. continuous hemodiafiltration ) for the treatment of ARF in the intensive care unit ( ICU ) . One hundred sixty-six patients were r and omized . Principal outcome measures were ICU and hospital mortality , length of stay , and recovery of renal function . RESULTS Using intention-to-treat analysis , the overall ICU and in-hospital mortalities were 50.6 and 56.6 % , respectively . Continuous therapy was associated with an increase in ICU ( 59.5 vs. 41.5 % , P < 0.02 ) and in-hospital ( 65.5 vs. 47.6 % , P < 0.02 ) mortality relative to intermittent dialysis .  Median ICU length of stay from the time of nephrology consultation was 16.5 days , and complete recovery of renal function was observed in 34.9 % of patients , with no significant group differences . Despite r and omization , there were significant differences between the groups in several covariates independently associated with mortality , including gender , hepatic failure , APACHE II and III scores , and the number of failed organ systems , in each instance biased in favor of the intermittent dialysis group . Using logistic regression to adjust for the imbalances in group assignment , the odds of death associated with continuous therapy was 1.3 ( 95 % CI , 0.6 to 2.7 , P = NS ) . A detailed investigation of the r and omization process failed to explain the marked differences in patient assignment . CONCLUSIONS A r and omized controlled trial of alternative dialysis modalities in ARF is feasible . Despite the potential advantages of continuous techniques , this study provides no evidence of a survival benefit of continuous hemodiafiltration compared with IHD . This study did not control for other major clinical decisions or other supportive management strategies that are widely variable ( for example , nutrition support , hemodynamic support , timing of initiation , and dose of dialysis ) and might material ly influence outcomes in ARF . St and ardization of several aspects of care or extremely large sample sizes will be required to answer optimally the questions originally posed by this investigation BACKGROUND Acute renal failure ( ARF ) is associated with a persistent high mortality in critically ill patients in intensive care units ( ICUs ) . Most studies to date have focused on patients with established , intrinsic ARF or relatively severe ARF due to multiple factors . None have examined outcomes of dialysis-dependent chronic renal failure [ end-stage renal disease ( ESRD ) ] patients in the ICU . We examined the incidence and outcomes of ARF in the ICU using a st and ard definition and compared these to outcomes of ICU patients with either ESRD or no renal failure . We sought to determine the impact of renal dysfunction and /or loss of organ function on outcome . METHODS We prospect ively scored 1530 admissions to eight ICUs over a 10-month period for illness severity at ICU admission using the Acute Physiological and Chronic Health Evaluation ( APACHE III ) evaluation tool .  Patients were defined as having ARF based on the definition of Hou et al ( Am J Med 74:243 - 248,1983 ) design ed to detect significant measurable declines in renal function based on serum creatinine . ESRD patients were identified as being chronically dialysis-dependent prior to ICU admission and the remainder had no renal failure . Clinical characteristics at ICU admission and ICU and hospital outcomes were compared between the three groups . RESULTS We identified 254 cases of ARF , 57 cases of ESRD and 1219 cases of no renal failure for an incidence of ARF of 17 % . Roughly half the ARF patients had ARF at ICU admission and the remainder developed ARF during their ICU stay . Only 11 % of ARF patients required  dialysis support . ARF patients had significantly higher acute illness severity scores than those with no renal failure , whereas patients with ESRD had intermediate severity scores . ICU mortality was 23 % for patients with ARF , 11 % for those with ESRD , and 5 % for those with no renal failure . There was no difference in outcome between patients who had ARF at ICU admission and those who developed ARF in the ICU . Patients with ARF severe enough to require dialysis had a mortality of 57 % . APACHE III predicted outcome very well in patients with no renal failure and patients with ARF at the time of scoring but underpredicted mortality in those who developed ARF after ICU admission and overestimated mortality in patients with ESRD . CONCLUSIONS ARF is common in ICU patients and has a persistent negative impact on outcomes , although the majority of ARF is not severe enough to require dialysis support . The mortality of patients with ARF from all causes is almost exactly similar to that noted using the same criteria two decades ago . More profound ARF requiring dialysis continues to have an even greater mortality . Nevertheless , acute declines in renal function are associated with a mortality that is not well explained simply by loss of organ function . The majority of ARF patients who did not require dialysis  still had a considerably higher mortality than the ESRD patients , all of whom required dialysis ; while ARF patients who did require dialysis  had a much higher morality than ESRD patients . APACHE III performs well and captures the mortality of patients with ARF at the time of scoring . Development of ARF after scoring has a profound effect on st and ardized mortality . We were unable to identify a unique mortality associated with ARF , but the presence of measurable renal insufficiency continues to be a sensitive marker for poor outcome A potential application of the continuous renal replacement therapies is the extracorporeal removal of inflammatory mediators in septic patients . Cytokine elimination with continuous renal replacement therapies has been demonstrated in several clinical studies , but so far without important effects on their serum concentrations . Improved knowledge of the cytokine removal mechanisms could lead to the development of more efficient treatment strategies . In the present study , 15 patients with septic shock and acute renal failure were observed during the first 24 h of treatment with continuous venovenous hemofiltration ( CVVH ) with an AN69 membrane .  After 12 h , the hemofilter was replaced and the blood flow rate ( QB ) was switched from 100 ml/min to 200 ml/min or vice versa . Pre- and postfilter plasma and ultrafiltrate concentrations of selected inflammatory and anti-inflammatory cytokines were measured at several time points allowing the calculation of a mass balance . Cytokine removal was highest 1 h after the start of CVVH and after the change of the membrane ( ranging from 25 to 43 % of the prefilter amount ) , corresponding with a significant fall in the serum concentration of all cytokines . The inhibitors of inflammation were removed to the same extent as the inflammatory cytokines . Adsorption to the AN69 membrane appeared to be the main clearance mechanism , being most pronounced immediately after installation of a new membrane and decreasing steadily thereafter , indicating rapid saturation of the membrane . A QB of 200 ml/min was associated with a 75 % increase of the ultrafiltration rate and a significantly higher convective elimination and membrane adsorption than at a QB of 100 ml/min . The results indicate that optimal cytokine removal with CVVH with an AN69 membrane could be achieved with a combination of a high QB/ultrafiltration rate and frequent membrane changes BACKGROUND Mortality rates of critically ill patients with acute renal failure ( ARF ) requiring renal replacement therapy ( RRT ) are high . Intermittent and continuous RRT are available for these patients on the intensive care units ( ICUs ) . It is unknown which technique is superior with respect to patient outcome . METHODS We r and omized 125 patients to treatment with either continuous venovenous haemodiafiltration ( CVVHDF ) or intermittent haemodialysis ( IHD ) from a total of 191 patients with ARF in a tertiary-care university hospital ICU . The primary end-point was ICU and in-hospital mortality , while recovery of renal function and hospital length of stay were secondary end-points . RESULTS During 30 months , no patient escaped r and omization for medical reasons . Sixty-six patients were not r and omized for non-medical reasons . Of the 125 r and omized patients , 70 were treated with CVVHDF and 55 with IHD . The two groups were comparable at 
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Similar to previously reported meta-analyses , we did not find a significant effect of CRRT on the OR of survival .
The progressive reduction in the OR of survival with CRRT relative to IHD might reflect progressive improvements in IHD .
The OR of DD was not affected by mode of RRT .
In conclusion , compared with IHD , CRRT does not offer an advantage with regards to survival or DD in ARF .