Medtronic, Inc.

Yu-Tung Wong

Michael R Van Driel

Jill E Uyeno

Darren S Gray

Victor C Lam

Jorge Jeffery

Aaron S Ingle

Amy P Noss

David L Zollinger

Craig R Meyer

Juan Carlos Flores

Both the number and the size of microair bubbles in a bloodstream are accurately determined optically, independently of oxygen saturation, by monitoring the intensity of light transmission in the 800-850 nm range through the bloodstream and indicating the count and amplitude range of peaks in the monitored intensity.

Optical detection and quantification of microair in blood

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

Microair bubbles in a bloodstream are diverted from the bloodstream in a diversion chamber by ultrasonic energy, and are collected in a blood-filled stasis column where they can be accurately measured by a bubble detector and then vented to atmosphere. Bubbles of different sizes can be separated into different stasis columns for enhanced measurement.

Ultrasonic diversion of microair in blood

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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Huntington Beach, CA, United States of America

Yu-Tung Wong