What is a fistula?
When you have haemodialysis, you need a site on the body where blood can be removed and returned. An arterio-venous fistula is designed for this. It is where an artery is connected to a vein, usually in the forearm. Connecting the artery to the vein makes more blood flow through the vein. This makes the vein larger and stronger and this makes it easier for repeated needle insertions.
What is an ultrasound scan of your fistula?
An ultrasound scan of your fistula may also be called a duplex or Doppler of your arm. This test uses ultrasound to produce images of your fistula. It is a safe and effective way to assess the blood flow through your fistula, and can determine whether it is working properly. The test is painless and does not use any radiation or needles. There are no risks associated with this test.
Where do I go?
The Vascular Studies Unit (VSU) is on level 5 of the Addenbrooke’s Treatment Centre (ATC). Please inform reception of your arrival straight away. There are often other clinics in progress so you may not be called in order of arrival. You may bring a relative or friend in with you during the test or request a chaperone if you would like one
What is consent?
Before your test is performed you must give your consent or permission. Consent is the process by which you give permission to health professionals to provide your care and treatment. It may be implied (offering your arm for a blood pressure reading) or formal (signing a formal consent form for an operation). In either case your consent must be given voluntarily and you must have all the information you need to make a decision. If you feel you do not have enough information or do not understand the procedure please ask
How is an ultrasound scan of your fistula performed?
There is no preparation required and you may eat and drink as usual prior to the test. A clinical vascular scientist (who might be male or female) will perform and interpret your ultrasound scan. The scan will be performed from the wrist to the neck if your fistula is on your arm, so you may be asked to remove your top so the scientist can scan the area of interest. The lights will be dimmed to allow the best images to be obtained. The scan will be performed with you lying down or seated on the edge of the couch. Gel is applied to your arm and the ultrasound probe will be moved along the area to assess the flow. The scan takes approximately 30 to 60 minutes. During the test, you may hear some “swooshing” noises from the ultrasound machine. These sounds are normal.
What happens next?
The clinical vascular scientist can comment briefly on the findings and will write a report for the consultant who requested the test. You will be able to discuss the results of this investigation fully with the referring team at your next outpatient appointment. In rare cases, the clinical vascular scientist may need to discuss the result with a doctor before you leave.