Tonometry system for determining blood pressure
First Claim
1. For use in a system for noninvasively determining the intra-arterial blood pressure of a patient, a tissue contact stress sensing apparatus comprising:
- a wafer having a continuous diaphragm for placing against a patient'"'"'s tissue which covers an underlying artery, said diaphragm adapted to be deformed in response to stress in said tissue caused by the intra-arterial blood pressure of said artery,semiconductor assembly means placed in close proximity to and spaced apart from said continuous diaphragm for directly,irradiating said diaphragm with electromagnetic radiation,receiving a portion of said electromagnetic radiation reflected from said continuous diaphragm, andwhereby the quantity of electromagnetic radiation received by said semiconductor assembly means is a function of the displacement of said continuous diaphragm in response to said tissue stress caused by said intra-arterial blood pressure of said artery.
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Accused Products
Abstract
A tissue contact stress sensing system incorporates a semiconductor assembly and a continuous diaphragm to noninvasively determine the intra-arterial blood pressure of a patient. The system comprises a continuous diaphragm placed against a patient'"'"'s tissue which covers an underlying artery. The semiconductor assembly is placed in close proximity to and spaced apart from the diaphragm for directly irradiating the diaphragm with electromagnetic radiation and receiving a portion of the electromagnetic radiation which is reflected from the continuous diaphragm. The disclosed system also utilizes a technique for minimizing the system errors associated with temperature drift and aging of the sensor.
147 Citations
57 Claims
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1. For use in a system for noninvasively determining the intra-arterial blood pressure of a patient, a tissue contact stress sensing apparatus comprising:
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a wafer having a continuous diaphragm for placing against a patient'"'"'s tissue which covers an underlying artery, said diaphragm adapted to be deformed in response to stress in said tissue caused by the intra-arterial blood pressure of said artery, semiconductor assembly means placed in close proximity to and spaced apart from said continuous diaphragm for directly, irradiating said diaphragm with electromagnetic radiation, receiving a portion of said electromagnetic radiation reflected from said continuous diaphragm, and whereby the quantity of electromagnetic radiation received by said semiconductor assembly means is a function of the displacement of said continuous diaphragm in response to said tissue stress caused by said intra-arterial blood pressure of said artery. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. For use in a system for noninvasively determining the intra-arterial blood pressure of a patient, a tissue contact stress sensor for generating a tissue contact stress signal indicative of said intra-arterial blood pressure and a correction signal for compensating for errors in said tissue contact stress signal caused by temperature drift and aging of said sensor, said system comprising:
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a wafer having a continuous diaphragm and a nonresponsive portion, said continuous diaphragm for placing against a patient'"'"'s tissue which covers an underlying artery, said diaphragm adapted to be deformed in response to said intra-arterial blood pressure of said artery, semiconductor assembly means spaced apart from and placed in close proximity to said continuous diaphragm for directly, irradiating said diaphragm with electromagnetic radiation, receiving a portion of said electromagnetic radiation reflected from said continuous diaphragm, converting said received radiation into a tissue contact stress signal which represents blood pressure data whereby the quantity of electromagnetic radiation which is received by said semiconductor assembly means is a function of the displacement experienced by said continuous diaphragm in response to said intra-arterial blood pressure of said artery, spacing structure coupled to said nonresponsive portion of said wafer and said semiconductor assembly means, said spacing structure fixing said separation between said semiconductor assembly means and said wafer, a portion of said semiconductor assembly means, spaced apart from and placed in close proximity to said nonresponsive portion of said wafer for directly, irradiating said nonresponsive portion of said wafer with electromagnetic radiation, receiving a portion of said electromagnetic radiation reflected from said nonresponsive portion of said wafer, converting said received radiation into a correction signal which represents reference data which is indicative of at least one reference factor, and whereby any change in the radiation received by said portion of said semiconductor assembly means is attributed to at least one of said reference factors and whereby said correction signal is combined with said tissue contact stress signal in a manner which minimizes the dependence of said blood pressure data on at least one of said reference factors. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38)
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39. A method for correcting errors in the output signal of a tissue contact stress sensor, said errors caused by the effects of aging and environmental factors on said sensor, said tissue contact stress sensor of the type having an element for placing against a patient'"'"'s tissue covering an artery of interest, said element responsive to tissue stress, comprising the steps of:
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constructing a tissue contact stress sensor and a reference sensor from substantially identical materials at substantially the same time, adapting said tissue contact stress sensor to be responsive to said element, adapting said reference sensor to be responsive to a fixed reference source which does not vary with said tissue contact stress measured by said tissue contact stress sensor, whereby an output signal of said reference sensor only changes as a function of said reference sensor aging, temperature and environmental factors, adapting said tissue contact stress sensor and said reference sensor to share the same environment so as to be equally influenced by aging and environmental factors, and combining the output signals generated by said tissue contact stress sensor and said reference sensor in a way which removes said influence of aging and environmental factors from said output of said tissue contact stress sensor.
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40. For use in a system for noninvasively determining the intra-arterial blood pressure of a patient, a miniaturized tissue contact stress sensing apparatus comprising:
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a silicon wafer having a nonresponsive portion and a continuous silicon diaphragm portion, said continuous silicon diaphragm portion for placing against a patient'"'"'s tissue which covers an underlying artery, said diaphragm adapted to be responsive to stress in said tissue caused by blood pressure pulsations in said underlying artery, integrated circuit means placed in close proximity to and spaced apart from said continuous diaphragm for directly, irradiating said diaphragm with electromagnetic radiation, receiving a portion of said electromagnetic radiation reflected from said continuous diaphragm, and whereby the quantity of electromagnetic radiation received by said integrated circuit means is a function of the tissue stress sensed by said continuous diaphragm, said tissue stress resulting from blood pressure pulsations in said underlying artery. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57)
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Specification