***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: Few studies adequately document adverse events in patients receiving long , slow , and overnight hemodialysis ( NHD ) .  Concerns about high rates of dialysis access complications have been raised . This is an observational cohort study comparing hospital admission rates for vascular access complications between alternate nightly NHD ( n=63 ) and conventional hemodialysis ( n=172 ) patients established on chronic hemodialysis for at least 3 months .  Overall , hospital admission rates and hospital admission rates for cardiac and all infective events are also reported . The NHD cohort was younger and less likely to be female , diabetic , or have ischemic heart disease than the conventional hemodialysis cohort .  When NHD and buttonhole cannulation technique were used simultaneously , there was a demonstrated increased risk of septic dialysis access events : incidence rate ratio 3.0 ( 95 % confidence interval 1.04–8.66 ) ( P=0.04 ) . The majority of blood culture isolates in NHD patients were gram‐positive organisms , particularly Staphylococcus aureus . Alternate nightly NHD did not significantly change total hospital admissions or hospital admissions for indications other than dialysis access complications , compared with conventional hemodialysis . Our data suggest that buttonhole cannulation technique should be used with caution in patients performing extended‐hours hemodialysis as this combination appears to increase the risk of septic access complications . R and omized‐controlled trials are needed to confirm these findings BACKGROUND In this r and omized clinical trial , we aim ed to determine whether increasing the frequency of in-center hemodialysis would result in beneficial changes in left ventricular mass , self-reported physical health , and other intermediate outcomes among patients undergoing maintenance hemodialysis . METHODS Patients were r and omly assigned to undergo hemodialysis six times per week  ( frequent hemodialysis , 125 patients ) or three times per week  ( conventional hemodialysis , 120 patients ) for 12 months . The two co primary composite outcomes were death or change ( from baseline to 12 months ) in left ventricular mass , as assessed by cardiac magnetic resonance imaging , and death or change in the physical-health composite score of the R AND 36-item health survey . Secondary outcomes included cognitive performance ; self-reported depression ; laboratory markers of nutrition , mineral metabolism , and anemia ; blood pressure ; and rates of hospitalization and of interventions related to vascular access . RESULTS Patients in the frequent-hemodialysis group averaged 5.2 sessions per week ; the weekly st and ard Kt/V(urea ) ( the product of the urea clearance and the duration of the dialysis session normalized to the volume of distribution of urea ) was significantly higher in the frequent-hemodialysis group than in the conventional-hemodialysis group ( 3.54±0.56 vs. 2.49±0.27 ) . Frequent hemodialysis was associated with significant benefits with respect to both co primary composite outcomes ( hazard ratio for death or increase in left ventricular mass , 0.61 ; 95 % confidence interval [ CI ] , 0.46 to 0.82 ; hazard ratio for death or a decrease in the physical-health composite score , 0.70 ; 95 % CI , 0.53 to 0.92 ) . Patients r and omly assigned to frequent hemodialysis were more likely to undergo interventions related to vascular access than were patients assigned to conventional hemodialysis ( hazard ratio , 1.71 ; 95 % CI , 1.08 to 2.73 ) . Frequent hemodialysis was associated with improved control of hypertension and hyperphosphatemia . There were no significant effects of frequent hemodialysis  on cognitive performance , self-reported depression , serum albumin concentration , or use of erythropoiesis-stimulating agents . CONCLUSIONS Frequent hemodialysis , as compared with conventional hemodialysis , was associated with favorable results with respect to the composite outcomes of death or change in left ventricular mass and death or change in a physical-health composite score but prompted more frequent interventions related to vascular access . ( Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others ; Clinical Trials.gov number , NCT00264758 . ) Background : Few studies have examined if infectious arteriovenous access complications vary with the cannulation technique and whether this is modified by dialysis frequency . We compared the infection rate between fistulas cannulated using buttonhole versus stepladder techniques for patients treated with short daily ( SDH ) or nocturnal hemodialysis at home ( NHD ) . We also compared patients receiving conventional intermittent hemodialysis ( CIHD )  using stepladder cannulation . Methods : Data were prospect ively collected from 631 patients dialyzed with a fistula from 2001 to 2010 ( Toronto and Ottawa , Canada ) . We compared the person-time incidence rate of bacteremia and local fistula infections using the exact binomial test . Results : Forty-six ( 7.3 % ) patients received SDH ( ≥5 sessions/week , 2 - 4 h/session ) , 128 ( 20.3 % ) NHD ( ≥4 sessions/week , ≥5 h/session ) and 457 ( 72 % ) CIHD ( 3 sessions/week , ≤4 h/session ) . Fifty percent of SDH and 72 % of NHD patients used the buttonhole technique . There were 39 buttonhole-related bacteremias ( rate : 0.196/1,000 fistula days ) and at least 2 local buttonhole site infections . Staphylococcus aureus accounted for 85 % of the bacteremias . There were 5 ( 13 % ) infection-related hospitalizations and 3 ( 10 % ) serious metastatic infections , including fistula loss . In comparison , there was 1 possible fistula-related infection in CIHD during follow-up ( rate : 0.002/1,000 fistula days ) . Conclusions : The rate of buttonhole-related infections was high among patients on frequent hemodialysis and more than 50 times greater than that among patients on CIHD with the stepladder technique . Most bacteremias were due to S. aureus - with serious consequences . The risks and benefits of buttonhole cannulation require individual consideration with careful monitoring , prophylaxis and management CONTEXT Morbidity and mortality rates in hemodialysis patients remain excessive . Alterations in the delivery of dialysis may lead to improved patient outcomes . OBJECTIVE To compare the effects of frequent nocturnal hemodialysis vs conventional hemodialysis on change in left ventricular mass and health-related quality of life over 6 months . DESIGN , SETTING , AND PARTICIPANTS A 2-group , parallel , r and omized controlled trial conducted at 2 Canadian university centers between August 2004 and December 2006 . A total of 52 patients undergoing hemodialysis were recruited . INTERVENTION Participants were r and omly assigned in a 1:1 ratio to receive nocturnal hemodialysis 6 times weekly or conventional hemodialysis 3 times weekly . MAIN OUTCOME MEASURES The primary outcome was change in left ventricular mass , as measured by cardiovascular magnetic resonance imaging . The secondary outcomes were patient-reported quality of life , blood pressure , mineral metabolism , and use of medications . RESULTS Frequent nocturnal hemodialysis significantly improved the primary outcome ( mean left ventricular mass difference between groups , 15.3 g , 95 % confidence interval [ CI ] , 1.0 to 29.6 g ; P = .04 ) . Frequent nocturnal hemodialysis did not significantly improve quality of life ( difference of change in EuroQol 5-D index from baseline , 0.05 ; 95 % CI , -0.07 to 0.17 ; P = .43 ) . However , frequent nocturnal hemodialysis was associated with clinical ly and statistically significant improvements in selected kidney-specific domains of quality of life ( P = .01 for effects of kidney disease and P = .02 for burden of kidney disease ) . Frequent nocturnal hemodialysis was also associated with improvements in systolic blood pressure ( P = .01 after adjustment ) and mineral metabolism , including a reduction in or discontinuation of antihypertensive medications ( 16/26 patients in the nocturnal hemodialysis group vs 3/25 patients in the conventional hemodialysis group ; P < .001 ) and oral phosphate binders ( 19/26 patients in the nocturnal hemodialysis group vs 3/25 patients in the conventional dialysis group ; P < .001 ) . No benefit in anemia management was seen with nocturnal hemodialysis . CONCLUSION This preliminary study revealed that , compared with conventional hemodialysis ( 3 times weekly ) , frequent nocturnal hemodialysis improved left ventricular mass , reduced the need for blood pressure medications , improved some measures of mineral metabolism , and improved selected measures of quality of life . TRIAL REGISTRATION is rct n.org Identifier : IS RCT N25858715 BACKGROUND The st and ard technique for fistula cannulation , the rope-ladder technique , is problematic for patients with short fistula lengths and for patients in whom the fistula is difficult to cannulate . The buttonhole technique , cannulation of exactly the same site , offers the advantage of an easy cannulation procedure . However , it can be used only in native fistulas and cannulation is preferably executed by a ' single-sticker ' . This study was conducted to compare these cannulation techniques using objective parameters . METHODS We introduced the buttonhole technique for self-cannulating home haemodialysis patients and compared it with baseline data obtained with the rope-ladder technique .  Thirty-three patients with a native arteriovenous fistula were observed prospect ively during 18 months on the following parameters : cannulating ease , number of bad sticks , pain , time of compression after cannula removal , bleeding , infectious complications and aneurysm formation . RESULTS With the buttonhole method , cannulating ease improved distinctly , which was especially favourable in patients with a short fistula vein . Reported cannulation pain did not change significantly . The incidence of bad sticks decreased significantly , as well as time of compression after cannula removal , without increased incidence of bleeding . Three patients developed a local skin infection of their buttonhole during the study , after which the disinfection routine prior to cannulation was changed . CONCLUSIONS Compared with the rope-ladder technique , the buttonhole method offers the advantage of an easier cannulation procedure with less bad sticks , which has a special benefit for patients with limited access cannulation sites or with a fistula which is difficult to cannulate . Prolonged compression times or re-bleeding episodes did not occur , but pre caution s have to be taken in order to prevent infectious complications . The buttonhole method can contribute considerably to the cannulating ease of self-cannulating patients , thus providing a better quality of life BACKGROUND Despite the growing interest in more frequent hemodialysis ( HD ) , to date , there have been no r and omized prospect i ve studies comparing outcomes in patients dialyzed using conventional thrice-weekly therapy with either the short hours daily or long slow nocturnal HD modalities . METHODS The London Daily/Nocturnal Hemodialysis Study , a prospect i ve , comparative , nonr and omized study , directly compared outcomes of  quotidian HD patients with conventional thrice-weekly HD patients . Patients were assigned to either daily HD ( n = 11 ) or nocturnal HD ( n = 12 ) and followed up for 5 to 36 months ; all data were directly compared with matched control patients receiving conventional HD . This report describes the study design , morbidity and mortality results , and vascular access results . RESULTS There were no significant differences between patient groups in total numbers of hospital admissions or hospital days . Likewise , there was no significant difference in number of emergency visits per patient-year . There were 3 patient deaths in each of the nocturnal HD and control groups , although none of the deaths was deemed related to HD treatment . No deaths occurred in the daily HD group . Vascular access differences between study groups were not statistically significant . Among patients with arteriovenous ( AV ) fistulae , more than 80 % of  daily HD and nocturnal HD patients elected to use the buttonhole technique and successfully performed quotidian HD through their buttonhole at the 18-month follow-up . Patients with AV fistulae had the lowest annual rates of access complications and interventions . The annual access infection rate for quotidian HD patients using catheters decreased significantly after patients switched from in-center conventional HD to more frequent HD treatments at home . CONCLUSION Results from this comprehensive and pioneering study support the hypothesis that quotidian HD is more physiological than conventional HD and results in better patient outcomes In the GRADE approach , r and omized trials start as high- quality evidence and observational studies as low- quality evidence , but both can be rated down if most of the relevant evidence comes from studies that suffer from a high risk of bias . Well-established limitations of r and omized trials include failure to conceal allocation , failure to blind , loss to follow-up , and failure to appropriately consider the intention-to-treat principle . More recently recognized limitations include stopping early for apparent benefit and selective reporting of outcomes according to the results . Key limitations of observational studies include use of inappropriate controls and failure to adequately adjust for prognostic imbalance . Risk of bias may vary across outcomes ( e.g. , loss to follow-up may be far less for all-cause mortality than for quality of life ) , a consideration that many systematic review s ignore . In deciding whether to rate down for risk of bias -- whether for r and omized trials or observational studies -- authors should not take an approach that averages across studies . Rather , for any individual outcome 
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On average , bacteremia and local infection rates were higher with CVC compared with AV access .
Access intervention rates were higher with more frequent hemodialysis , but access survival did not differ .
Buttonhole cannulation was associated with bacteremia rates similar to those seen with CVCs in some series .
Topical mupirocin seemed to attenuate this effect .
No direct comparisons of closed connector devices versus st and ard luer-locking devices were found .
Low rates of actual or averted ( near misses ) air embolism and bleeding were reported with closed connector devices .