Hemodialysis access flow measurement. Comparison of ultrasound dilution and duplex ultrasonography

Decreased hemodialysis access flow is associated with an increased risk of access thrombosis. Duplex ultrasonography can measure access flow and select a subset of patients at increased risk for access failure. With in-line techniques (ultrasound dilution), access flow can be measured during hemodialysis. This study attempted to determine if access flow measured by ultrasound dilution (QA-T) was comparable to that measured by duplex ultrasonography (QA-S). The authors performed 66 simultaneous measurements of hemodialysis access flow in 19 patients by ultrasound dilution and duplex ultrasound with time-domain correlation during 19 hemodialysis treatments. The mean access flow was 1,086 +/- 505 ml/min by ultrasound dilution and 1,026 +/- 513 ml/min with duplex ultrasonography (NS). Regression analysis revealed a linear relationship between the two techniques described by the equation QAT = 246.14 + 0.8104(QAS) (correlation coefficient of 0.83; p < 0.0001). Measurement of hemodialysis access flow by ultrasound dilution was essentially equivalent to that obtained by duplex ultrasound. Additional studies are needed to determine if regular in-line flow measurements can predict and prevent future access thrombosis and decreased the cost of access management.