Flexible diaphragm tonometer
First Claim
1. A pressure waveform monitor for noninvasively monitoring the pressure waveform inside a vessel, comprising:
- a container having an opening;
a flexible diaphragm extended across said opening such that said container is effectively closed by said diaphragm, said diaphragm being adapted to bend responsively to vessel pressure when said diaphragm is placed against tissue covering the vessel;
fluid disposed within said closed container;
means for altering a volume of fluid in said container in response to bending of said diaphragm;
where said altering is one of increasing or decreasing; and
means for determining a pressure within said container.
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Accused Products
Abstract
A pressure waveform monitor for non-invasively monitoring the pressure waveform inside a vessel, such as an artery, includes a flexible diaphragm extended across an opening of a container containing a fluid. The flexible diaphragm is placed against tissue surrounding an artery such that arterial pressure causes a deflection in the diaphragm. A deflection in the diaphragm causes the fluid to be redistributed throughout the container which is effectively divided into an array of volume compartments. The relative volume distribution is determined through impedance plethysmography. The diaphragm is maintained in a calibrated position by maintaining the array of volume compartments at relatively unchanged volumes. When the relative volumes remain essentially unchanged, calibrated tonometry is possible. The pressure within the container is then used to determine the pulse waveform and the pressure within the artery.
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Citations
24 Claims
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1. A pressure waveform monitor for noninvasively monitoring the pressure waveform inside a vessel, comprising:
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a container having an opening; a flexible diaphragm extended across said opening such that said container is effectively closed by said diaphragm, said diaphragm being adapted to bend responsively to vessel pressure when said diaphragm is placed against tissue covering the vessel; fluid disposed within said closed container; means for altering a volume of fluid in said container in response to bending of said diaphragm;
where said altering is one of increasing or decreasing; andmeans for determining a pressure within said container. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A pressure waveform monitor for noninvasively monitoring the pressure waveform inside a vessel, comprising:
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a container having an opening; a flexible diaphragm extended across said opening such that said container is effectively closed by said diaphragm, said diaphragm having a calibrated position, said diaphragm being adapted to bend responsively to vessel pressure when said diaphragm is placed against tissue adjacent the vessel; fluid within said closed container; means for dividing said container into adjacent compartments, said compartments being in relative communication such that said fluid moves freely between said compartments said compartments having respective volumes that are in an essentially fixed ratio when said diaphragm is in said calibrated position; means for determining individual volumes within each of said compartments when said diaphragm bends responsively to vessel pressure and thereby distributes said fluid throughout said container; means for supplying additional fluid to said container when the individual volumes of said compartments change relative to each other due to said vessel pressure such that the individual volumes are maintained in a essentially fixed ratio; and means for determining a pressure within said container when said individual volumes are maintained in an essentially fixed ratio, whereby the pressure waveform within a vessel is determined.
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19. A pressure waveform monitor for non-invasively monitoring the pressure waveform inside a vessel, comprising:
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a container having an opening; a flexible diaphragm extended across said opening such that said container is effectively closed by said diaphragm, said diaphragm being adapted to bend responsively to vessel pressure when said diaphragm is placed adjacent tissue overlying the vessel; fluid disposed within said effectively closed container; means for dividing said container into a plurality of volume compartments; means for determining respective fluid volumes within each said volume compartment; and means for determining a pressure within said container. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification