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US 5,859,366 AGranted
Strain gage measurement of blood volume in soft-shell venous reservoirs
AssigneeMedtronic, Inc.
InventorsMichael R. Van Driel, Darren S. Gray, Victor C. H. Lam, Jill E. Uyeno, Yu-Tung Wong
Life of this patent
Estimating the term…
Abstract
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.
Claims4
A system for measuring the blood volume in a expandable soft-shell venous reservoir, comprising:
- a) a rigid backplate;
- b) a soft-shell venous reservoir planarly mounted on said backplate;
- c) at least one strain gage so positioned with respect to said reservoir as to produce an electrical signal in response to an expansion strain in the material of said soft-shell reservoir, said reservoir being formed by a pair of plastic sheets which are bonded to each other in a peripheral area but separable in a central area to form an expandable blood container, and in which a plurality of strain gages are bonded to said sheets in said peripheral area.
A system for measuring the blood volume in an expandable soft-shell venous reservoir, comprising:
- a) a rigid backplate;
- b) a soft-shell venous reservoir planarly mounted on said backplate;
- c) a frame;
- d) a deformable film mounted in said frame and carrying at least one strain gage arranged to produce a signal representative of deformation stress in said film;
- e) said frame being so movable with respect to said backplate as to bias said sheet into contact with said reservoir throughout the expansion thereof;
- and
- d) apparatus arranged to compute and display the blood volume in said reservoir by electrically comparing said signal with signals produced by known volumes of blood in said reservoir.
4 more elements
Dependencies are inferred from the claim text.