***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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    Input: CONTEXT Although acute renal failure ( ARF ) is believed to be common in the setting of critical illness and is associated with a high risk of death , little is known about its epidemiology and outcome or how these vary in different regions of the world . OBJECTIVES To determine the period prevalence of ARF in intensive care unit ( ICU ) patients in multiple countries ; to characterize differences in etiology , illness severity , and clinical practice ; and to determine the impact of these differences on patient outcomes . DESIGN , SETTING , AND PATIENTS Prospect i ve observational study of ICU patients who either were treated with renal replacement therapy ( RRT ) or fulfilled at least 1 of the predefined criteria for ARF from September 2000 to December 2001 at 54 hospitals in 23 countries . MAIN OUTCOME MEASURES Occurrence of ARF , factors contributing to etiology , illness severity , treatment , need for renal support after hospital discharge , and hospital mortality . RESULTS Of 29 269 critically ill patients admitted during the study period , 1738 ( 5.7 % ; 95 % confidence interval [ CI ] , 5.5%-6.0 % ) had ARF during their ICU stay , including 1260 who were treated with RRT . The most common contributing factor to ARF was septic shock ( 47.5 % ; 95 % CI , 45.2%-49.5 % ) . Approximately 30 % of patients had preadmission renal dysfunction . Overall hospital mortality was 60.3 % ( 95 % CI , 58.0%-62.6 % ) . Dialysis dependence at hospital discharge was 13.8 % ( 95 % CI , 11.2%-16.3 % ) for survivors . Independent risk factors for hospital mortality included use of vasopressors ( odds ratio [ OR ] , 1.95 ; 95 % CI , 1.50 - 2.55 ; P<.001 ) , mechanical ventilation ( OR , 2.11 ; 95 % CI , 1.58 - 2.82 ; P<.001 ) , septic shock ( OR , 1.36 ; 95 % CI , 1.03 - 1.79 ; P = .03 ) , cardiogenic shock ( OR , 1.41 ; 95 % CI , 1.05 - 1.90 ; P = .02 ) , and hepatorenal syndrome ( OR , 1.87 ; 95 % CI , 1.07 - 3.28 ; P = .03 ) . CONCLUSION In this multinational study , the period prevalence of ARF requiring RRT in the ICU was between 5 % and 6 % and was associated with a high hospital mortality rate Objective To evaluate the effects of short-term , high-volume hemofiltration ( STHVH ) on hemodynamic and metabolic status and 28-day survival in patients with refractory septic shock . Design Prospect i ve , interventional . Setting Intensive care unit ( ICU ) , tertiary institution . Patients Twenty patients with intractable cardiocirculatory failure complicating septic shock , who had failed to respond to conventional therapy . Interventions STHVH , followed by conventional continuous venovenous hemofiltration . STHVH consisted of a 4-hr period during which 35 L of ultrafiltrate is removed and neutral fluid balance is maintained . Subsequent conventional continuous venovenous hemofiltration continued for at least 4 days . Measurements and Main Results Cardiac index , systemic vascular resistance , pulmonary vascular resistance , oxygen delivery , mixed venous oxygen saturation , arterial pH , and lactate were measured serially . Fluid and inotropic support were managed by protocol . Therapeutic endpoints were as follows during STHVH : a ) by 2 hrs , a ≥50 % increase in cardiac index ; b ) by 2 hrs , a ≥25 % increase in mixed venous saturation ; c ) by 4 hrs , an increase in arterial pH to > 7.3 ; d ) by 4 hrs , a ≥50 % reduction in epinephrine dose . Patients who attained all four goals ( 11 of 20 ) were considered hemodynamic “ responders ” ; patients who did not ( 9 of 20 ) were considered hemodynamic “ nonresponders . ” There were no differences in baseline hemodynamic , metabolic , and Acute Physiology and Chronic Health Evaluation and Simplified Acute Physiology Scores between responders and nonresponders . Survival to 28 days was better among responders ( 9 of 11 patients ) than among nonresponders ( 0 of 9 ) . Factors associated with survival were hemodynamic-metabolic response status , time interval from ICU admission to initiation of STHVH , and body weight . Conclusions These data suggest that STHVH may be of major therapeutic value in the treatment of intractable cardiocirculatory failure complicating septic shock . Early initiation of therapy and adequate dose may improve hemodynamic and metabolic responses and 28-day survival BACKGROUND There is uncertainty on the effect of different dialysis modalities for the treatment of patients with acute kidney injury ( AKI ) , admitted to the intensive care unit ( ICU ) . This controlled clinical trial performed in the framework of the multicentre SHARF 4 study ( Stuivenberg Hospital Acute Renal Failure ) aim ed to investigate the outcome in patients with AKI , stratified according to severity of disease and r and omized to different treatment options . METHODS This was a multicentre prospect i ve r and omized controlled trial with stratification according to severity of disease expressed by the SHARF score . ICU patients were eligible for inclusion when serum creatinine was > 2 mg/dL , and RRT was initiated . The selected patients were r and omized to intermittent ( IRRT ) or continuous renal replacement therapy ( CRRT ) . RESULTS A total of 316 AKI patients were r and omly assigned to IRRT ( n = 144 ) or CRRT ( n = 172 ) . The mean age was 66 ( range 18 - 96 ) ; 59 % were male . Intention-to-treat analysis revealed a mortality of 62.5 % in IRRT compared to 58.1 % in CRRT ( P = 0.430 ) . No difference between IRRT and CRRT could be observed in the duration of ICU stay or hospital stay . In survivors , renal recovery at hospital discharge was comparable between both groups . Multivariate analysis , including the SHARF score , APACHE II and SOFA scores for correction of disease severity , showed no difference in mortality between both treatment modalities . This result was confirmed in pre-specified subgroup analysis ( elderly , patients with sepsis , heart failure , ventilation ) and after exclusion of possible confounders ( early mortality , delayed ICU admission ) . CONCLUSIONS Modality of RRT , either CRRT or IRRT , had no impact on the outcome in ICU patients with AKI . Both modalities need to be considered as complementary in the treatment of AKI ( Clinical Trial : SHARF 4 , NCT00322933 , http:// Clinical Trials.gov ) Objective To determine if circuit life is influenced by a higher pre-dilution volume used in CVVH when compared with a lower pre-dilution volume approach in CVVHDF . Design A comparative crossover study . Cases were r and omized to receive either CVVH or CVVHDF followed by the alternative treatment  . Subjects All patients ≥ 18 yrs of age who required CRRT while in ICU were eligible to participate , but excluded if coagulopathic , thrombocytopenic or unable to receive heparin . Based on an intention-to-treat , 45 patients were r and omized to receive either CVVH or CVVHDF followed by the alternative treatment . Setting : A 24-bed , tertiary , medical and surgical adult intensive care unit ( ICU ) . Intervention Blood flow rate , vascular access device and insertion site , hemofilter , anticoagulation and machine hardware were st and ardized . An ultrafiltrate dose of 35 ml/ kg/h delivered pre-filter was used for CVVH . A fixed pre-dilution volume of 600 mls/h with a dialysate dose of 1 L was used for CVVHDF . Results Thirty-one patients received CVVH or CVVHDF out of 45 participants followed by the alternative technique . There was a significant increase in circuit life in favor of CVVHDF ( median=16 h 5 min , range=40 h 23 min ) compared with CVVH ( median=6 h 35 min , range=30 h 45 min ) . A Mann-Whitney U test was performed to compare circuit life between the two different CRRT modes ( Z=-3.478 , p<0.001 ) . Measurements of circuit life on the 93 circuits which survived to clotting ( 50 CVVH and 43 CVVHDF ) were log transformed prior to under taking a st and ard multiple regression analysis . None of the independent variables - activated prothrombin time ( aPTT ) , platelet count , heparin dose , patient hematocrit or urea - had a coefficient partial correlation > 0.09 ( coefficient of the determination=0.117 ) or a linear relationship which could be associated with circuit life ( p=0.228 ) . Conclusion Pre-diluted CVVHDF appeared to have a longer circuit life when compared to high volume pre-diluted CVVH . The choice of CRRT mode may be an important independent determinant of circuit life BACKGROUND The optimal intensity of renal-replacement therapy in critically ill patients with acute kidney injury is controversial . METHODS We r and omly assigned critically ill patients with acute kidney injury and failure of at least one nonrenal organ or sepsis to receive intensive or less intensive renal-replacement therapy . The primary end point was death from any cause by day 60 . In both study groups , hemodynamically stable patients underwent intermittent hemodialysis , and hemodynamically unstable patients underwent continuous venovenous hemodiafiltration or sustained low-efficiency dialysis . Patients receiving the intensive treatment strategy underwent intermittent hemodialysis and sustained low-efficiency dialysis six times per week and continuous venovenous hemodiafiltration at 35 ml per kilogram of body weight per hour ; for patients receiving the less-intensive treatment strategy , the corresponding treatments were provided thrice weekly and at 20 ml per kilogram per hour . RESULTS Baseline characteristics of the 1124 patients in the two groups were similar . The rate of death from any cause by day 60 was 53.6 % with intensive therapy and 51.5 % with less-intensive therapy ( odds ratio , 1.09 ; 95 % confidence interval , 0.86 to 1.40 ; P=0.47 ) . There was no significant difference between the two groups in the duration of renal-replacement therapy or the rate of recovery of kidney function or nonrenal organ failure . Hypotension during intermittent dialysis occurred in more patients r and omly assigned to receive intensive therapy , although the frequency of hemodialysis sessions complicated by hypotension was similar in the two groups . CONCLUSIONS Intensive renal support in critically ill patients with acute kidney injury did not decrease mortality , improve recovery of kidney function , or reduce the rate of nonrenal organ failure as compared with less-intensive therapy involving a defined dose of intermittent hemodialysis three times per week and continuous renal-replacement therapy at 20 ml per kilogram per hour . ( Clinical Trials.gov number , NCT00076219 . OBJECTIVE To compare two forms of continuous renal replacement therapy , continuous venovenous hemofiltration ( CVVH ) vs. continuous venovenous hemodialysis ( CVVHD ) , in terms of the removal of inflammatory mediators from the blood of patients with systemic inflammatory response syndrome and acute renal failure . DESIGN R and omized crossover , clinical study . SETTING University teaching hospital . PATIENTS Thirteen patients with systemic inflammatory response syndrome and acute renal failure receiving continuous renal replacement therapy . INTERVENTION Patients were r and omized to receive either convective clearance using CVVH or diffusive clearance using CVVHD for the first 24 hrs , followed by the other modality for 24 hrs . All treatments utilized AN69 hemofilters . CVVH was performed with an ultrafiltration rate of 2 L/hr and CVVHD with a dialysis outflow rate of 2 L/hr . MEASUREMENTS AND MAIN RESULTS Plasma and ultrafiltrate concentrations of tumor necrosis factor (TNF)-alpha , interleukin (IL)-6 , IL-10 , and sL-selectin were measured at 0 , 1 , 3 , 6 , 12 , and 24 hrs by radioimmunoassay . Plasma endotoxin concentrations were also measured at 0 , 12 , and 24 hrs by chromogenic assay . CVVH was associated with a 13 % decrease in plasma TNF-alpha concentrations compared with a 23 % increase while on CVVHD ( p < .05 ) . Mean plasma concentrations of IL-6 , IL-10 , and sL-selectin were unchanged over time and between therapies . Only minimal amounts of mediators were recovered in the effluents with either therapy except for IL-6 . The clearances for IL-6 were different between therapies , 1.9+/-0.8 ( SD ) mL/min for CVVHD and 3.3+/-1.5 mL/min for CVVH , ( p < .01 ) . Plasma endot 
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We found no effect of hemofiltration on mortality ( risk ratio ( RR ) 0.96 , 95 % confidence interval ( CI ) 0.73 to 1.25 , P = 0.76 ; three trials , n = 121 ( primary analysis ) ; RR 1.10 , 95 % CI 0.88 to 1.38 , P = 0.38 ; eight trials , n = 540 ( sensitivity analysis ) ) or other clinical outcomes ( RRT dependence in survivors , vasopressor use , organ dysfunction ) compared to hemodialysis .
Data primarily from crossover RCTs suggested that hemofiltration increased clearance of medium to larger molecules , including inflammatory cytokines , compared to hemodialysis , although almost no studies measured changes in serum concentrations .
Conclusions Data from small RCTs do not suggest beneficial clinical outcomes from hemofiltration , but confidence intervals were wide .
Hemofiltration may increase clearance of medium to larger molecules .