Publications by authors named "T Chilipka"

We have developed a blood flow measurement system using Doppler ultrasound flow sensors fabricated of thin and flexible piezoelectric-polymer films. These flow sensors can be wrapped around a blood vessel and accurately measure flow. The innovation that makes this flow sensor possible is the diffraction-grating transducer.

View Article and Find Full Text PDF

Access graft failure is a major problem in hemodialysis. Monitoring the flow through the access so that impending failure can be detected and prevented seems reasonable, but recent clinical trials have failed to show any benefit of such monitoring. Described here are plans for a clinical trial of a new flow monitoring procedure that measures access flow weekly instead of monthly and, being performed before dialysis, avoids the dialysis-induced changes in graft flow that may have affected earlier trials.

View Article and Find Full Text PDF

A new ultrasound instrument has been developed, using vector Doppler and embedded machine intelligence, to enable measurement of access flow rates by non-specialists. Ultrasound measurement of access flow can be performed with the patient off the dialysis machine, avoiding the hemodynamic changes that may affect indicator-dilution methods. A research version of the instrument was tested on flow phantoms simulating graft flow, and showed accuracy better than 5%.

View Article and Find Full Text PDF

Background: A new Doppler flowmeter using a special transducer forming two ultrasound beams to insonate vessels was developed. This low-cost flowmeter allows the flow to be measured independently of the angle of insonation.

Methods: Sixty-five flow determinations were made in the carotid arteries of five pigs.

View Article and Find Full Text PDF