potential caution: extended-hours home hemodialysis and buttonholes

[natnnnat]

http://onlinelibrary.wiley.com/doi/10.1111/j.1542-4758.2010.00463.x/abstract

Van EPS, C. L., JONES, M., NG, T., JOHNSON, D. W., CAMPBELL, S. B., ISBEL, N. M., MUDGE, D. W., BELLER, E. and HAWLEY, C. M. (2010), The impact of extended-hours home hemodialysis and buttonhole cannulation technique on hospitalization rates for septic events related to dialysis access. Hemodialysis International, 14: 451–463. doi: 10.1111/j.1542-4758.2010.00463.x

Keywords:

    * buttonhole cannulation;
    * cardiovascular disease;
    * complications;
    * hospitalization;
    * nocturnal hemodialysis;
    * sepsis

Abstract

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. Randomized-controlled trials are needed to confirm these findings.

[MooseMom]

Well, of course buttonhole cannulation should be used "with caution" in extended-hours dialysis patients (why don't they just call it "nocturnal"?).  ALL cannulation of any sort at any time for how ever many hours should be used "with caution".  Anytime you stick a couple of needles in someone's arm, it should be done "with caution".  So, how do you think they define "caution"?  Don't use buttonholes, or use buttonholes but use some sort of special protective measures?  Any ideas on how to make it safer?  Do you think it's possible that people who are able to use buttonholes for nocturnal (and these people must be dialysis pros!) might get a little cavalier, hence higher infection rates?  Just askin'.

[greg10]

Easy now, MM, don't shoot the messenger    The following paper may be relevant in that it showed that topical mupirocin prophylaxis (MP) resulted in no infections with BHC, at least in their limited study.  This makes sense as BHC results in a tunnel into the fistula and is subjected to more opportunistic infection.

http://cjasn.asnjournals.org/content/5/6/1047.short

Buttonhole (constant-site) cannulation (BHC) continues to gain popularity with home and in-center dialysis programs worldwide. However, long-term safety data are lacking. This paper reports the authors' single-center experience with Staphylococcus aureus bacteremia (SAB) and the efficacy of topical mupirocin prophylaxis (MP).Design, setting, participants, & measurements: This study was a retrospective prepost comparison of SAB rates after establishing MP. Fifty-six consecutive patients on home nocturnal hemodialysis via arteriovenous fistulae, mean age 51.5 ± 10.6 years, 38% women, and vintage 44.5 ± 34.5 months were observed for a total of 93.4 (pre-MP) and 193.5 (post-MP) patient-years.Ten episodes of SAB were observed, with metastatic complications in four cases, including pneumonia (n = 2), septic arthritis, and a fatal C3 epidural abscess. When analyzed by observation period, the odds ratio (OR) for SAB before versus after the introduction of MP was 6.4 [95% confidence interval (CI) = 1.3 to 32.3; P = 0.02]. Two SAB episodes occurred after the MP started. Both patients had discontinued the MP for 3 weeks (nonadherent) preceding infection; hence, no SAB episodes were observed on treatment. In an as-treated analysis, the OR for SAB in the absence of MP was 35.3 (95% CI = 2.0 to 626.7; P = 0.01).BHC is associated with a significant risk of SAB with metastatic complications. In this prepost comparison of SAB rates, no infections were observed with MP. While awaiting more definitive studies, this simple intervention should be considered for patients using BHC.

[Bill Peckham]

I don't have access to the whole article but I'd like to know the details of people's cannulation technique. That article Greg links to suggests one intervention but in general I think this is mostly a result of improper scab removal and or pre-procedure washing.

These observational studies can have technique issues. I think this one is out of Australia but it would be interesting to know what their training practices were.

Greg I don't know about that making sense. Sepsis requires something to enter the blood stream, really the only time that can happen is when the needle is inserted. Any other time there is an opening to the blood path, blood will be leaving the track - nothing is going to be going in.

[Hemodoc]

I discussed this issue with my nephrologist last month.  He has converted his entire in-center dialysis unit to buttonhole cannulation for all patients and they have had an increase in septic events.  I believe much of this is technique related.

I use sterile, disposable tweezers in combination with a 21 gauge needle to pick my scabs cleaned first with alcohol.  Then when hooking up, I use betadine, other preps cause allergic reactions to my skin.  I use the same prep I did for my patients getting any in office procedure. Start with a small circular, or in my care oval and then work to the outside, don't use the same swab to go back to the center.  I use a second, doing the same thing, center to outer. Betadine needs to dry completely to be effective which can take up to 10 minutes but I usually don't wait the full 10 minutes.  I was always taught to remove the excess betadine with alcohol to prevent inflammation from the betadine on the tissues from the needle.  Then I am ready to insert the needles.

Other people have their own variations of the prep, but I do prep a fairly large area around the buttonhole site and I use mask and gloves.  Access infections are not only inconvient, they truly can be deadly leading to not only sepsis, but metastatic spread of bacteria to the lungs causing pneumonia, heart valve damage from endocarditis, spread to bones and other tissues. Fortunately, an intact immune system routinely clears bacteria in the blood from routine activities we don't even think about such as brushing our teeth.

Avoiding infections anywhere on our skin is important since other sites of infection can migrate by the blood to the fistula.  This is most important with the arm your fistula is on. 

In my mind, the risk to the fistula from the other techniques is not well studies as well and the attendant complications that can occur with needing a new access placed. The prevention of aneurysm formation is well documented in the literature by buttonhole cannulation and is one of the primary reasons I chose that for my own access.  Nevertheless, there does appear to be a real risk of increased sepsis with buttonholes mandating my opinion very careful adherence to all infection control techniques when cannulating.  The wonder is not that there are infections with reusing the same site over and over again, but that in the majority of cases, there are no infection issues.

[MooseMom]

Hemodoc, have you discussed your infection control techniques with your neph?  Perhaps he can learn from you!

[Zach]

Here is an interesting article from the American Nephrology Nurses’ Association.  It addresses one possible cause of site infections.

How Do You Prevent Indented Buttonhole Sites?
http://www.nwrenalnetwork.org/Fist1st/Hubbing.pdf

 

[natnnnat]

I do have access to the full article.  If anyone would like the PDF I can email it to you privately, but I quail at pasting the whole thing here for reasons of copyright.  Instead I have cut and pasted much of it  8-|

Bill and Hemodoc are right, the discussion section suggests a list of possible reasons why there might be "septic events", and some of their suggestions are about technique.  See text of the discussion section which I have dumped below. 

I think when they suggest "caution" they are not talking about people being careful when needling buttonholes but that they are addressing the nephrology community, saying, be cautious with your optimistic / enthusiastic support of buttonholes with nocturnal until we can work out what is happening with the septic events.  To quote from the conclusion:  "Alternate nightly home NHD is a safe and sustainable therapy with many associated potential benefits. However, our enthusiasm must always remain tempered by a careful analysis of both the positive and negative attributes of such novel therapies and our data should serve as a warning that careful attention needs to be given to septic access events in these patients until more definitive information is available."  Looking over the introduction, they seem to be pointing out that buttonholing and / or nocturnal are associated with a whole range of established positives including "improvements in bone mineral metabolism, hypertension, left ventricular hypertrophy, nutrition, anemia, sleep disorders, and quality of life" for extended hours hemo, and "Buttonhole cannulation technique has been shown to decrease pain, improve ease and speed of cannulation, and reduce hematoma formation compared with the conventional method of rotating cannulation sites up and down the length of the access, also known as the “rope ladder technique” (RL). A preference for BH has been reported by patients managed using quotidian therapies.5  Initial studies have focused on anatomic and thrombotic access complications and results suggest that increased frequency dialysis may protect against dialysis access complications".  Having established all these benefits, this paper looks at the potential problems associated with septic events.

I have looked it over a few times, but I can't see a discussion of the specifics of how they trained people e.g. to remove their scabs.  Just, as shown below, a discussion of where such techniques might be contributing to the problem.

They point out that "Randomized-controlled trials are needed to confirm these findings."  In the body of the paper they point this out again by commenting on how such a trial should be set up.  They are saying that this is an area which hasn't a lot of published research, and more needs to be done. 

acronyms used:
BH = buttonhole
RL = "rope laddering"
CHD=conventional hemodialysis; NHD=nocturnal hemodialysis.



Study design and population

This is an observational cohort control study. The NHD group was recruited between 2003 and 2006 and consisted of ESRD patients; aged 18 years and over; established on conventional home hemodialysis for at least 3 months; managed by the Princess Alexandra Hospital, Australia who consented to change from a conventional dialysis regimen (<6 hours per session for <4 sessions weekly [3–4 sessions weekly, 4–5 hours per session in the majority]) to nocturnal home hemodialysis performed overnight 6 to 9 hours per session for 3.5 to 5 sessions weekly. Within the range of 3.5 to 5 sessions weekly and 6 to 10 hours per session, patients tailored their dialysis regimen to suit their lifestyle and sleeping habits. Interdialytic durations longer than 2 days were discouraged. Changes to the dialysis prescription are outlined in Table 1. On entry into the study, patients were required to have a functional AVF or AVG. If necessary, patients could continue home NHD with temporary internal jugular, tunneled, cuffed, and central venous dialysis catheter (CVC) access. Arteriovenous fistulae and AVGs were cannulated with two 14 or 15 G needles. Buttonhole cannulation technique, as described by Twardowski and colleagues, was used to access most fistulae and RL technique for all grafts.

[snip]

Discussion
This is the first published study suggesting that there may be an increased risk of septic events related to dialysis access when NHD and BH are used simultaneously in patients on home hemodialysis. Sepsis accounted for the majority of deaths in the NHD cohort and is known to be a leading cause of morbidity and mortality in the general hemodialysis population.8,9 However, this study is not powered to detect a significant difference between the 2 groups in mortality related to sepsis. Alternate nightly NHD did not significantly reduce total hospital admissions or admissions for cardiac events compared with CHD.

Adverse events related to vascular access

There are sparse reports in the literature supporting or refuting our findings. The possibility of increased rates of infection related to permanent dialysis access with quotidian hemodialysis has been previously alluded to in the literature, particularly from centers also utilizing BH.10 Previous studies of BH suggest that infection rates may tend to increase compared with RL.3,11,12 In particular, van Loon et al.12 reported that the BH technique may be associated with increased access infection rates compared with the rope ladder method in a center-based dialysis cohort. Similar to the findings of Perl et al., we showed no significant differences in the rates of infectious or noninfectious CVC complications.13

However, the majority of reports relating to NHD and/or BH have only reported overall event rates rather than specific access infection rates.2,14 Combining septic and nonseptic dialysis access event rates for analysis may mask important changes occurring in each individual category, which become evident when results are analyzed separately. This is demonstrated in our analyses.

There are a number of putative mechanisms that may explain the possible interaction between long dialysis hours at home and BH in promoting septic access complications. These include features of the BH itself, cannulation technique, duration of dialysis, dialyzing over night, and the influence of the home environment.

In relation to the BH characteristics per se, we hypothesize that there may be an increased organism load near the cannulation sites in patients using BH. As the BH site is effectively a chronic wound, gram-positive organisms that typically reside on the skin may chronically colonize BH sites. This hypothesis is supported by the high rates of bacteremias with gram-positive skin commensal organisms in our cohort. Moreover, the fibrous tissues surrounding the cannula in a buttonhole, as compared with more elastic tissue around a RL site, may also fail to contract as tightly around the needle, thus failing to form as good a barrier against organisms tracking along the needle shaft.

Patient technique at home may also be a significant causative factor. The use of contaminated instruments during scab removal from over the BH before cannulation provides a potential opportunity for organisms to be introduced into the cannulation site. The presence of the reusable enuresis monitors at the access site may represent another possible means of introducing infection close to the cannulation sites, particularly if they are not regularly and thoroughly cleaned.

Increasing the degree to which the skin is breached by either increasing the duration that cannulae are in situ or the number of cannulae may increase infection risk. Some groups have used single-needle cannulation techniques in NHD and this may have reduced their rates of dialysis access-related complications.

In addition, being asleep during dialysis may increase the risk of infection as arm movement when patients are sleeping on dialysis may be more likely to bring their cannulation sites into contact with contaminated objects compared with when patients are alert and more conscious of protecting the access site.

In our center, BH and NHD are exclusively performed in the home setting where cannulation is performed by patients or their carers rather than qualified nursing staff. This may be a confounding factor that our data set cannot address. Significantly, Piccoli et al. did not find cannulation at home to be a significant risk factor for dialysis access events compared with cannulation by nursing staff in a limited care facility.15

We did not note an increase in bacteremia in the NHD compared with the CHD group. These bacteremia rates include infections that were thought to originate from the vascular access as well as those originating from other sources. This may explain why the possible increase in vascular access-related septic events in the NHD group is not also reflected in the bacteremia rates. There were too few bacteremias in our cohort to perform any further subanalysis of bacteremias originating from access as opposed to other sources. An alternative explanation may be that, despite efforts to standardize admission criteria, the threshold for admitting NHD patients with changes suspicious for access sepsis was lower than that applied to the CHD group due to concerns regarding their relative isolation performing dialysis at home.

It has been suggested that need for intervention to correct fistula flow or pressure deficits, fistula limb failure, and fistula failure rates tended to reduce with the use of BH compared with RL. This has biological plausibility as BH has been shown to reduce failed cannulation attempts and hematoma and aneurysm formation.3,12,16 Quotidian hemodialysis itself has been postulated to reduce dialysis access complications by reducing intradialytic hypotension, lowering blood flow rates, and reducing uremic thrombopathy.2 After correcting for differences in access type, location and age, diabetes, gender, BMI, and smoking status, we did not find any protective effect from BH cannulation on nonseptic permanent access event rates. Access event rates were related to factors that reflect general blood vessel quality including a history of smoking, upper arm as opposed to forearm access location, and longevity of the dialysis access rather than to cannulation technique. It is plausible that the presence of a reliable and long-lasting dialysis access with which patients and staff are familiar may improve the ease of cannulation and therefore reduce damage to the access and introduction of infection from failed and repeated cannulation attempts.

Our results highlight the important impact of both access characteristics and cannulation technique on vascular access complication rates. Future studies should strive to fully describe all aspects of dialysis access and cannulation technique to tease out their effects on access event rates.

Hospital admission rates and cardiovascular adverse events

[snip]

Our study has a number of strengths. It is a single-center study with uniform protocols and procedures for patient management and has been conducted at a unit with >30 years experience in training and maintaining patients on home-based hemodialysis. Robust multivariable analyses using both count and survival analyses have been utilized to minimize confounding and verify findings using alternate models.

However, our study has limitations. We are comparing a group of patients on home hemodialysis with a group managed with in-center or satellite modalities. These groups are different in many important ways including patient motivation, compliance, and psychosocial parameters that cannot reliably be adjusted for in multivariable analysis. This is a problem with any similar cohort analysis. In addition, the era of observation is not exactly the same for the groups, raising the possibility of vintage bias. Apart from adjusting for duration of renal replacement therapy, we did not measure or adjust for potential differences in residual renal function in our patient population. Although we admit that residual confounding is a possibility, the home hemodialysis patients were younger and generally fitter than the in-center cohort. Furthermore, as a group, home hemodialysis patients are recognized to have better psychosocial support as this is necessary to enable them to dialyze at home. Thus, taking into account the characteristics of the 2 groups, 1 would expect the home hemodialysis cohort to have had a superior, rather than an inferior outcome.

Our group has examined the sample size required for a randomized-controlled trial to explore definitely whether BH is associated with an increased rate of septic events compared with RL. To have 90% power to detect a 25% increase in infectious events, a sample size of 3400 is required with an accrual period of 3 years and a minimum follow-up period of 1 year based on the best available data on event rates. This would almost certainly require an international collaborative effort.

Our unit's response to these data has been not to offer BH first-line in all patients but to reserve this technique for patients with specific indications for this technique, namely AVF that are short and/or difficult to access and patients with recalcitrant needle phobias. In addition, we have altered our protocol to mandate the use of a surgical scrub with long residual antibacterial activity for arm cleansing before cannulation and the application of a sealed dressing over the cannulation sites during nocturnal hemodialysis. Pierratos and colleagues have reported success in reducing S. aureus bacteremias using topical application of mupirocin to the cannulation sites.21 However, this latter technique may promote the development of antibiotic-resistant strains over time.

[greg10]

Thanks everybody, especially natnnnat for starting the thread and posting part of the article.  You guys do good work.

[del]

Hubby has been doing nocturnal using buttonholes for over 4 years with no problems at all. We have used a couple of different techniques. Right now we use sterile tweezers, alcohol swabs (hubby has a reaction from other types), and a blunt plastic needle on the end of a 3 cc syringe(one for each site) to remove the scabs. We swab the same way - in a circular motion - not going back to the scab. We always make sure our hands are well washed and use hand sanitizer a lot.  Every month we both have to do nasal swabs to make sure we don't have some type of germ in our nose. If it comes back that we do we have to start putting cream in our nose each month.

[tyefly]

Every month we both have to do nasal swabs to make sure we don't have some type of germ in our nose. If it comes back that we do we have to start putting cream in our nose each month.


Seriously   Del..... you swab your nose.....    maybe just use a mask...LOL

[Bill Peckham]

Every month we both have to do nasal swabs to make sure we don't have some type of germ in our nose. If it comes back that we do we have to start putting cream in our nose each month.


Seriously   Del..... you swab your nose.....    maybe just use a mask...LOL

I hold my breath.