When kidneys fail, they can no longer remove waste products and excess fluid from the body, leading to end-stage renal disease. Dialysis becomes necessary to perform these functions. Effective dialysis requires consistent, reliable bloodstream access, allowing a large volume of blood to be processed by a machine. Understanding access options, especially a dialysis fistula, is valuable for those undergoing this therapy.
Understanding Dialysis Access
Hemodialysis removes waste and extra fluid from the blood by circulating it through an external filter. This process demands a high rate of blood flow and repeated access to blood vessels. Attempting to use standard veins for frequent needle insertions would quickly damage them, making a dedicated, robust access point essential for ongoing treatment.
There are three primary types of vascular access for hemodialysis: arteriovenous (AV) fistulas, arteriovenous (AV) grafts, and central venous catheters. While central venous catheters provide immediate access for temporary or emergency dialysis, they carry higher risks of infection and other complications. AV grafts, which involve a synthetic tube connecting an artery and a vein, are another option. However, the AV fistula is the preferred long-term solution due to its lower complication rates, including fewer infections and clotting issues, and its longer lifespan.
The Dialysis Fistula Explained
A dialysis fistula is a surgically created connection between an artery and a vein. This connection is made in the arm, often at the wrist or elbow. Normally, arteries carry oxygenated blood from the heart under high pressure, while veins return deoxygenated blood to the heart under lower pressure.
The surgical procedure directly joins an artery to a neighboring vein. This reroutes high-pressure arterial blood flow into the vein. The increased blood flow and pressure cause the vein to enlarge and its walls to thicken, a process called arterialization or maturation. This maturation usually takes between 6 to 12 weeks, as the vein strengthens and expands, becoming suitable for the repeated needle insertions required for dialysis.
During a dialysis session, two needles are inserted into the matured fistula. One needle draws blood from the body, which then travels through tubing to the dialysis machine’s filter. Inside the filter, waste products and excess fluid are removed from the blood. The cleaned blood then returns to the body through the second needle inserted into the fistula. This continuous circulation allows for effective blood purification.
Caring for Your Fistula
Proper care is important for maintaining the function and longevity of a dialysis fistula. Protecting the arm with the fistula is a primary consideration. This involves avoiding activities that could compress or injure the fistula, such as wearing tight jewelry or clothing, carrying heavy objects, or having blood pressure taken or blood drawn from that arm.
Regular monitoring of the fistula helps ensure it is working correctly. Two key indicators are the “thrill” and the “bruit.” The thrill is a buzzing sensation felt by gently touching the fistula, similar to a cat’s purr. The bruit is a whooshing sound caused by the high-pressure blood flow through the connection. Feeling a thrill and hearing a bruit indicate that the fistula has good blood flow.
Observe the fistula for any signs of problems. Swelling, redness, unusual warmth, or pain around the fistula site could indicate an infection or other complication. Changes in the thrill or bruit, such as a decrease in intensity or their complete absence, can signal a blood clot or narrowing within the fistula, which requires immediate medical attention. Maintaining good hygiene around the access site and promptly reporting any concerns to healthcare providers helps preserve fistula health.