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Disclaimer: This article is for informational purposes only and is not intended to be a substitute for medical advice or diagnosis from a physician.
In order for blood to be removed from the body and filtered through the dialyzer, or artificial kidney, to replace kidney function, a vascular access must be created. The purpose of the vascular access is to create strong enough blood flow for hemodialysis, whether you do it from home or at a center. The recommended access for hemodialysis is the arteriovenous (AV) fistula.
An AV fistula is considered the gold-standard vascular access because there is least risk of infection and clotting than with the AV graft or central venous catheter. An AV fistula is surgically created by connecting an artery and a vein, usually in an arm or leg. After the fistula is created, it will need to heal and mature for weeks or months before it can be used for hemodialysis. Your doctor may recommend exercises, such as squeezing a rubber ball, to increase blood flow which helps make the fistula bigger and stronger. Talk to your doctor about your access type and ask if a fistula can work for you.
To access the blood for hemodialysis, two needle sticks are placed in the vascular access. One needle is in the arterial side, which carries blood away from the heart and into the dialyzer, while the other needle is in the venous side which returns the filtered blood back into the body toward the heart. Another term for the needle sticks is cannulation. When the dialysis needles are placed into the blood vessels, this is cannulation. Needle cannulation is important to help keep your fistula healthy and working properly.
The rope ladder technique rotates the needle placement sites each time the patient has hemodialysis. Currently, this is the most frequently used cannulation method in the United States. For the ladder technique, think of climbing the rungs on a ladder and how your hands are evenly spaced apart. Each time you go to dialysis, the technician should choose a site about one-and-a-half to two inches from the last puncture site.
The ladder technique is used to help expand the lifespan of the fistula. Changing cannulation site gives the previous needle site time to heal and prevents aneurysms from forming.
Buttonhole technique or constant site cannulation has been more frequently used in Europe and Japan for more than 25 years, although it is becoming more popular in the U.S. because more people have AV fistulas. With the increase of fistulas being created, the buttonhole technique has been gaining popularity.
With the buttonhole technique, the hemodialysis needles are inserted into the exact same spot, at the exact same angle and the exact same depth for each hemodialysis treatment. The buttonhole cannulation site needs to be established by the same person cannulating the site every time. The site for buttonhole cannulation should be chosen carefully, taking into consideration the angle that you can most easily insert (self-cannulate) the needles. The buttonhole technique is recommended for those who self-cannulate either in the hemodialysis center or when performing home hemodialysis.
After about 10 cannulations using sharp dialysis needles, the buttonhole site will develop a scar tunnel track. This track is the same as a pierced ear that has scar tissue formed and will cause less to no pain and bleeding when cannulating. After the buttonhole is created, a blunt dialysis needle should be used, which eliminates the risks of cuts and bleeding to the tract.
Many people are confused when hearing about the buttonhole technique, in which the same site is used for cannulation, because it appears to go against the reasons for the rope ladder technique in which the stick site is moved. Problems, such as aneurysms, can occur from using only one small area over again for needle sticks, which can weaken that area. Using a constant site, as done with the buttonhole technique, or rotating the stick site using the full length of the fistula, as done with the ladder technique, is different and doesn’t cause this issue.
Studies have shown that there are advantages in using the buttonhole technique. These advantages were discovered by chance during a study of AV fistulas; one patient had a fistula with a limited stick area, so it was necessary to use a constant site. It was discovered that this patient had little pain during cannulation, it was done more quickly and there were no complications to the site or the fistula. Other patients in the study were then switched to the buttonhole technique with similar results, including:
While the buttonhole technique seems to show excellent results, people who dialyze on consecutive days found that sticking the same site each time was painful. To remedy the issue, two sets of buttonhole sites were developed and then alternated. Another problem is when the needle “just won’t go in.” In this case, it may be necessary to gently pull the needle back and realign within the buttonhole tract.
Because a fistula is an all-natural part of the body, everyone’s fistula is unique. You may want to talk to your doctor or dialysis nurse about the two types of cannulation techniques described in this article. You and your health care professional can decide which method would be best for you. Many patients who use the buttonhole technique for self-cannulation report that taking more responsibility for their health and well being is empowering.
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