An arteriovenous (AV) graft is a surgically created connection between an artery and a vein, typically in the arm, providing access for hemodialysis. This procedure is performed when a patient’s veins are unsuitable for a direct AV fistula. The presence of a “bruit” and a “thrill” are expected indicators of a properly functioning AV graft, signaling intended blood flow for dialysis treatments.
Understanding Bruit and Thrill
A “bruit” is a distinct whooshing or buzzing sound heard over the AV graft site. This sound is generated by the rapid, turbulent blood flow as it moves from the high-pressure artery into the lower-pressure vein through the graft. Hearing this continuous, gentle, and rhythmic sound confirms blood movement within the graft.
A “thrill” is a palpable vibration or “buzzing” sensation felt when lightly touching the skin over the graft. This vibration also results from turbulent blood flow, indicating the connection is open and blood circulates effectively. Both are physical manifestations of altered blood flow dynamics within the surgically created access.
Why These Signs Mean a Healthy Graft
A consistent bruit and thrill are positive signs for an AV graft, indicating it is open and functioning as designed. These sensations confirm strong, free blood flow through the graft, signifying it is patent and not clotted or significantly narrowed. A healthy AV graft will have a continuous bruit and a soft, continuous thrill.
These findings are the expected outcomes after AV graft placement, signaling the graft is ready for or successfully supporting dialysis treatments. The strong blood flow through the graft allows for efficient removal of waste products during hemodialysis. A functional graft with a good bruit and thrill helps ensure the longevity of the access point for ongoing treatment.
When to Seek Medical Attention
The absence of a bruit or thrill, or a noticeable change in their quality, can indicate the graft may be clotting or narrowing. Warning signs include a weaker, inconsistent, or absent thrill, or a change in the bruit from a whooshing sound to a whistle-like sound. These alterations suggest potential issues such as stenosis (narrowing of the blood vessel) or thrombosis (a blood clot).
Contact a healthcare provider immediately if these changes are observed. Prompt intervention can often save the graft and prevent more serious complications. Other signs warranting immediate medical attention include persistent arm swelling, presence of collateral veins, prolonged bleeding after needle withdrawal, or changes in hand color or temperature.
Caring for Your AV Graft
Maintaining your AV graft’s health involves several important daily practices to ensure its longevity. Regularly checking for the presence and quality of the bruit and thrill is an important routine. This daily check helps in early detection of potential problems.
Protect the graft arm from injury; avoid lifting heavy objects or sleeping on it. Also, avoid wearing tight clothing, jewelry, or having blood pressure cuffs applied to the graft arm, as these can restrict blood flow. Keeping the graft site clean with antibacterial soap or rubbing alcohol before dialysis helps prevent infection.