By Peter Laird, MD
Buttonhole cannulation is a beneficial procedure in prolonging the health of dialysis fistulas in the home hemodialysis population. Known also as constant site cannulation, it is useful especially in patients who have limited sites for rotation on a fistula. Recent concerns from the FHN revealed an increased risk of vascular access procedures and infections. Part of the difficulty with the FHN data is a lack of documentation on how many of these complications occured in patients self cannulating or in those that had nurses cannulating with the buttonhole technique. In many ways, buttonhole cannulation is only an option when a patient or one dedicated care giver acceses the site. Even minor changes in the angle of entry will render the buttonhole unusable. An old video from Dr. Stanley Shaldon is a reminder of how far we have come since the early days of self cannulation. (Not for the faint of heart)
I have been fortunate to utilize buttonhole cannulation for nearly five years without any complications to date other than a very small thrombosis which required me to move to another buttonhole location. By God's grace, I have yet to have a single infection in my dialysis access. I believe that there are several factors that contribute to this fortunate outcome, not the least of which is my my medical training on how to perform minor surgical procedures and the importance of proper skin preparation techniques.
I start my dialysis session by setting up my home hemodialysis machine and then let it "cook" while doing other pre-dialysis chores. I always shower prior to dialysis and place clean clothes. I have an upper arm fistula also called a brachiocephalic fistual for the brachial artery and cephalic vein used to create this access. My first step when beginning my buttonhole cannulation is "pick" the scabs. I use a bit of an unorthodox technique for scab removal with a 21 ga needle that many experts on cannulation don't recommend, but it works for me by being diligent and very gentle with the needle and essentially peeling the scab away without digging or creating a larger wound. Other techniques for softening the scab work well for many patients, but didn't seem to soften my scabs enough to work in my situation. The key in any of these techniques is to avoid excess trauma to the buttonhole site with scab removal which opens the door to infection through tissue damage.
I always start first prior to scab removal by cleaning the entire area with an alcohol pad. One issue that many do not consider is that the arterial and venous sites are essentially two separate wounds and you should avoid cross contamination. I use one needle for the arterial and a new needle for the venous site. In addition, many use metal, reusable tweezers to assist in picking the scabs once they start to peel. This can be a source of serious infections with drug resistant bacteria that are difficult to completely clean from metal objects. I use a plastic, disposable but sterile tweezers for each buttonhole and never use one on both buttonholes. Lastly, once I have peeled my scabs off, I keep the area free of all clothing by taping the shirt sleeve to my shoulder prior to removing the scabs.
In addition, I avoid excess dust in the dialysis area by closing the heating and cooling vents on our central air system in the dialysis room. My wife is a great help in this area since she was a supervisor in housekeeping at the hospital where we met. After twenty years in this relationship, I have had to adapt to her hygiene expectations of picking up my clothes and making the bed in the morning since I am usually the last one up. I truly hate the smell of bleach, but it is a regular ingredient in all of our bathrooms, I just ask that she let me leave the house first. My wife has always hated clutter and it makes for a perfect home dialysis setting.
After I have finished the final preparation of the machine and am ready to cannulate, I start once again by cleaning the entire area with alcohol pads being careful to avoid touching the cleansed skin with my hands in any manner. Many dialysis units now send us very small and skimpy alcohol pads and I must simply use two at a time to avoid contaminating the skin while trying to clean it. At this point I have surgical mask and non-latex gloves as does my wife. Once the alcohol has dried, I use betadine pads that I apply in a circular manner to a large area around both buttonholes. My dialysis nurses and my wife believe that my excessive application of betadine paint to such a large area is over kill, but with nearly five years of infection free daily cannulation, who can argue with success.
The key here is to use the standard surgical prep technique of starting from the center and work to the outside of the area cleansed in larger and larger circular motion where you NEVER go from the outside back to the center. I utilize betadine due to an allergic skin reaction to other more effective agents. When using betadine, there are two more precautions to keep in mind with this topical cleanser. First, you must let it dry completely before cannulation and lastly, betadine is irritating to open wounds so I also remove it carfully with several alcohol pads until the skin directly surround the buttonholes has only a faint trace of yellow. The chemical irritation of betadine in a catheter or needle tract can lead to inflammation that increases the risk of infections.
At this point, I use a very careful technique to avoid contaminating the cleansed buttonhole and gently insert the needle along the established track while at the same time pulling the skin taught with my fourth and fifth fingers of the same hand. I hold the needle between my thumb and index finger in a modified touch cannulation. I would point out that I cannot cannulate using this techique in a few seconds as I see many nurses in dialysis centers attempt with a quick swab of alcohol and jam the needle away. It is a bit time consuming to say the least. However, despite some studies suggesting increased complications with buttonholes, I suspect that they are in part due to lack of diligent technique especially when used in a dialysis center with a high patient turnover every day. Buttonhole cannulation is a safe and effective manner of preserving the fistula from aneurysm formation and it is easy to learn how to develop your own sites should you need to abandon an established site once you are home using sharp needles temporally.
Last of all, I place a clean bandaide over the buttonhole before I pull the needles out and then a pressure bandage on top. One issue I have done since starting dialysis is to avoid placing any tape directly over the insertion site. Anyone that has medical tape on their arm for any length of time understands that the adhesive to the tape stays even after washing and scrubbing with alcohol. Preventing tape on the open hole keeps that adhesive from gathering dirt and bacteria. After I have the pressure bandage on for two hours after dialysis, I take it off, clean off the remaining betadine with alcohol and replace the soiled bandaids with clean bandaides that I keep on for another 8 hours while the protective scab is reforming.
I believe that this is the final culmination of all the previous steps I take to avoid infections. Blood is a great food source for bacteria as noted in the popular blood agar used in microbiology labs for bacterial cultures. I must confess to being quite paranoid about these issues since I have spent a great deal of my professional life caring for serious access related infections in septic dialysis patients. You can become critically ill in a matter of only a few hours for simply neglecting to be diligent at all times.
I cherish the independence that buttonhole cannulation offers. It can be challenging at times and as with any procedure, there are specific complications that can occur no matter how careful you are. But for myself, with nearly five years and only a very small aneurysm on my venous site that is clinically unimportant, not a single infection and not a single vascular intervention, I recommend that all patients who are capable of self cannulation should consider this as an optimal access method. My wife hates my methodical approach to cannulation and rolls her eyes from time to time, but at this point, it is too late to teach an old dog any new tricks. I believe that slow and methodical is the only approach when you continually use a constant site to cannulate. I am continually amazed by the lack of any infection in two continuously open wounds in my arm that defies all of my medical training, but it simply works and works well when done well.