What does a positive thrill indicate when assessing a fistula?

A positive thrill when assessing a fistula indicates working blood flow. The presence of a thrill—an audible vibration felt over the fistula site—demonstrates that blood is flowing through the vascular access efficiently. This is a critical assessment for patients with fistulas, as it confirms that the access is functioning properly for hemodialysis.

In this context, a thrill is a sign that the fistula has matured and that an adequate volume of blood is being passed through it, which is essential for the dialysis process to be effective. If the thrill is absent or diminished, it may suggest potential complications, which would require further investigation.

In contrast, the other scenarios such as severe infection, blood clot, or low blood pressure do not directly correlate with the presence of a thrill. Severe infection might lead to other clinical signs and symptoms, while a blood clot could result in a loss of thrill altogether. Low blood pressure is a systemic issue and doesn’t specifically indicate the status of the fistula itself. Therefore, a positive thrill is a clear indicator of effective blood flow in a functioning fistula.