ultrasound dilution technique, a technique for measuring blood flow and access recirculation in hemodialysis patients. Ultrasound sensors are attached to the venous and arterial catheters in their normal positions and blood flow is checked. Then they are reversed; the ultrafiltration is turned off, and at a known flow rate, a bolus of saline is released into the venous catheter to dilute the blood. The velocity of the dilution as it passes through the access apparatus is measured by ultrasonography.
