Flexible diaphragm tonometer
First Claim
1. A method of noninvasively monitoring the pressure waveform of a vessel, comprising the steps of:
- (A) providing a container filled with a volume of fluid and having a flexible diaphragm forming one side of the container, the flexible diaphragm having a calibrated position;
(B) placing the flexible diaphragm against tissue generally covering the vessel such that the diaphragm effectively becomes an extension of the tissue whereby the diaphragm is deflected across a portion of the diaphragm in response to stresses in the tissue against which it is placed, the stresses being caused by vessel pressure;
(C) adjusting the volume of fluid within the container to return the diaphragm to the calibrated position from the deflected position; and
(D) determining the pressure within the container when the diaphragm returns to said calibrated position, whereby the pressure waveform of a vessel is determined.
6 Assignments
0 Petitions
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
14 Claims
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1. A method of noninvasively monitoring the pressure waveform of a vessel, comprising the steps of:
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(A) providing a container filled with a volume of fluid and having a flexible diaphragm forming one side of the container, the flexible diaphragm having a calibrated position; (B) placing the flexible diaphragm against tissue generally covering the vessel such that the diaphragm effectively becomes an extension of the tissue whereby the diaphragm is deflected across a portion of the diaphragm in response to stresses in the tissue against which it is placed, the stresses being caused by vessel pressure; (C) adjusting the volume of fluid within the container to return the diaphragm to the calibrated position from the deflected position; and (D) determining the pressure within the container when the diaphragm returns to said calibrated position, whereby the pressure waveform of a vessel is determined. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of noninvasively monitoring the pressure waveform of a vessel, using a flexible diaphragm tonometer, comprising the steps of:
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(A) placing a flexible diaphragm tonometer having a plurality of volume compartments adjacent tissue generally surrounding the vessel; (B) monitoring the respective volume of each volume compartment and placing the tonometer in a calibrated condition; and (C) determining the pressure within the tonometer when the tonometer is in the calibrated condition, whereby the pressure waveform of the vessel is determined. - View Dependent Claims (11, 12, 13, 14)
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Specification