What is a Radial Cephalic AV Fistula Exam Like?

TL;DR

A physical examination of a radial cephalic AV fistula involves assessing three key features: thrill, bruit, and pulsatility. These indicators help identify normal versus abnormal blood flow. Additionally, three bedside tests—pulse augmentation, arm elevation, and sequential occlusion—can evaluate inflow and outflow, as well as detect accessory veins that may impact the fistula's function.

Transcript

let's learn about the key points related to physical examination of a fistula shown in this cartoon is a radial cephalic AV fistula between the radial artery marked in red and the cephalic vein marked in blue the yellow arrows denote the direction of blood through the fistula and black arrows point to the site of anastomosis remember is you go more... Read More

Key Insights

• 😋 The content explains the anatomy of a radial cephalic AV fistula and the direction of blood flow through it.
• ❓ Thrill, bruit, and pulsatility are important features of a normal fistula and can indicate any abnormalities.
• 💗 Three bedside tests, including pulse augmentation, arm elevation, and sequential occlusion, are useful for assessing inflow, outflow, and detecting accessory veins in a fistula.
• 🥺 Venous outflow stenosis can cause a hyper pulsatile fistula, while inflow stenosis can lead to hypo or flat pulsatility.
• 🌥️ Accessory veins that are large enough can compete with the fistula for blood and cause poor vein maturation and early failure.

Questions & Answers

Q: What are the important features of a normal fistula?

A normal fistula should have a palpable, continuous thrill indicating uninterrupted flow, a low-pitched rumbling bruit with systolic and diastolic components, and soft pulsatility. A high-pitched howling bruit with only a systolic component may indicate stenosis.

Q: How can you assess inflow and outflow of a fistula?

Inflow can be assessed using the pulse augmentation test, where manually causing venous outflow obstruction should cause the fistula to appear hyper pulsatile if inflow is adequate. Outflow can be assessed using the arm elevation test, where raising the forearm above the heart level should flatten the fistula if there is no venous outflow obstruction.

Q: How can you detect accessory veins in a fistula?

Accessory veins can be visible on inspection or detected using the sequential occlusion test. In this test, occluding the fistula close to the anastomosis will make the thrill disappear, but if there is a large accessory vein, the thrill will re-emerge when moving downstream to include the accessory vein in the flow.

Q: How can accessory veins affect a fistula?

Accessory veins that compete with the main draining vein can decrease flow through the fistula, lead to poor vein maturation, and cause early fistula failure. Coil embolization of the accessory vein may help in such cases.

Summary & Key Takeaways

• The content explains the anatomy of a radial cephalic AV fistula and clarifies the terminology used.

• It describes the three important features of a normal fistula: thrill, bruit, and pulsatility.

• The content introduces three bedside tests to assess inflow and outflow of a fistula and check for accessory veins.