What finding indicates a patent arteriovenous fistula?

• A. A palpable thrill and audible bruit over the fistula site.
• B. Absence of thrill.
• C. Redness around the site without bruit.
• D. Pain at the site with fever.

Answer: (A)

A functioning arteriovenous fistula is indicated by a palpable thrill and an audible bruit over the access site. The thrill is a vibration you can feel from the rapid, turbulent blood flow as arterial blood enters the vein through the fistula. The bruit is the rushing sound heard with a stethoscope from that same turbulent flow. Together, they show the fistula is open and supplying adequate flow for dialysis. If the thrill or bruit is absent, the fistula may be failing due to narrowing or clotting. Redness around the site without a bruit can signal irritation or infection, and pain with fever points to infection rather than patency.