Herbert Hauser

US Patent:

42056888, Jun 3, 1980

Filed:

May 23, 1977

Appl. No.:

5/799218

Inventors:

Herbert H. Hauser - New York NY
Marie-Lucienne Tannieres - Paris, FR

Assignee:

Doll Research, Inc. - New York NY

International Classification:

A61B 502

US Classification:

128694

Abstract:

A blood flowmeter responsive only to the pulsatile component of blood flow is combined with apparatus for converting normal blood flow in a limb to fully pulsated flow to provide accurate zero baseline and total flow information. Preferably, the arterial flow in a limb is fully pulsatized by inflating a pressure cuff, which surrounds the limb on the distal side of a flow sensor location, to a pressure at or slightly above the local diastolic pressure. Arterial flow in the limb is thereby occluded during the diastolic and post-diastolic period of each heart cycle, preventing any flow that otherwise typically occurs during this period. The resulting pulsatile flow during the higher pressure systolic period will increase to compensate for any lost residual forward flow during the post-diastolic period; so that the total net forward flow with the cuff pressurized is approximately the same as the total net forward flow without the cuff pressurized. The altered flow is totally pulsatile, however. Subtraction of the integrated flow measured without cuff pressure from the integrated flow measured with the cuff pressurized yields a value approximately equal to any residual diastolic flow, which otherwise could not be measured by certain non-invasive magnetic flowmeters.