Medtronic, Inc.

Victor C Lam

Michael R Van Driel

Yu-Tung Wong

Darren S Gray

Jill E Uyeno

Amy P Noss

Blood volume in a soft-shell venous reservoir is measured for real-time display by ultrasonically measuring the distance between the walls of the reservoir bag at representative points and determining the volume of the bag by an interpolation based on the known shape of the reservoir bag as it expands and contracts.

Ultrasonic blood volume measurement in soft-shell venous reservoir

The blood volume contained in a soft-shell venous reservoir is measured by using strain gauges to detect variations in the expansion stress imposed upon the reservoir material or a film overlying the reservoir as the reservoir fills.

Strain gage measurement of blood volume in soft-shell venous reservoirs

The blood volume in a soft-shell venous reservoir is measured by immersing the reservoir in a fluid and measuring the displacement of that fluid, either by measuring a liquid level in an overflow tube or by measuring the temperature-compensated gas pressure if the displaced fluid is a gas in a sealed container. Equipment operable from outside the container to measure the reservoir or to expel air therefrom is also disclosed.

Measuring blood volume in soft-shell venous resevoirs by displacement

An accurate real-time volume measurement of the blood content of a soft-shell venous reservoir is obtained by computing the volume from the weight of the blood in the reservoir modified by the hematocrit of the blood.

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Honolulu, HI, United States of America

Victor C Lam