Method and apparatus for determination of physiological parameters using cervical impedance
First Claim
1. An apparatus, comprising:
- an electrode configured to be extravascularly implanted, the extravascularly-implanted electrode adapted for encircling extravascular nerve tissue near a blood vessel without encircling the blood vessel;
an electrical energy delivery circuit configured to be coupled to the extravascularly-implanted electrode and configured to;
provide an electrical test signal directed from the extravascularly-implanted electrode to a location internal to a patient body and near the blood vessel when the electrode encircles the extravascular nerve tissue without encircling the blood vessel; and
provide an electrostimulation signal directed from the extravascularly-implanted electrode toward the extravascular nerve tissue when the electrode encircles the extravascular nerve tissue without encircling the blood vessel;
a detector circuit configured to receive an electrical response signal in response to the electrical test signal; and
a signal processor circuit, coupled to the electrical energy delivery circuit and the detector circuit, the signal processor circuit configured to;
determine a vessel dimension of the blood vessel near the extravascularly-implanted electrode using the received electrical response signal;
compare the determined vessel dimension to a reference vessel dimension to determine a vessel dimension change; and
output an indication of the determined vessel dimension change.
1 Assignment
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Accused Products
Abstract
Implanted electrodes can be used to deliver electrical stimulation signals to areas near blood vessels, nerves, or other internal body locations. In an example, an electrode can be implanted in a cervical location and can be used to measure dimensional changes in an artery using impedance plethysmography. Measured artery dimensional changes can be used to determine one or more physiological parameters associated with a patient'"'"'s health status, such as pulse transit time, relative pulse pressure, or aterial compliance, among others. These parameters can be used to monitor a patient health status or to modulate a patient'"'"'s therapy, among other uses. In some examples, an electrode configured to deliver an electrostimulation signal to nerve tissue can be used to provide non-neurostimulating electrical stimulation plethysmography signals near a blood vessel.
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Citations
20 Claims
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1. An apparatus, comprising:
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an electrode configured to be extravascularly implanted, the extravascularly-implanted electrode adapted for encircling extravascular nerve tissue near a blood vessel without encircling the blood vessel; an electrical energy delivery circuit configured to be coupled to the extravascularly-implanted electrode and configured to; provide an electrical test signal directed from the extravascularly-implanted electrode to a location internal to a patient body and near the blood vessel when the electrode encircles the extravascular nerve tissue without encircling the blood vessel; and provide an electrostimulation signal directed from the extravascularly-implanted electrode toward the extravascular nerve tissue when the electrode encircles the extravascular nerve tissue without encircling the blood vessel; a detector circuit configured to receive an electrical response signal in response to the electrical test signal; and a signal processor circuit, coupled to the electrical energy delivery circuit and the detector circuit, the signal processor circuit configured to; determine a vessel dimension of the blood vessel near the extravascularly-implanted electrode using the received electrical response signal; compare the determined vessel dimension to a reference vessel dimension to determine a vessel dimension change; and output an indication of the determined vessel dimension change. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of using an extravascularly-implanted electrode positioned at an extravascular nerve tissue, the method comprising:
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providing an electrical test signal directed from the extravascularly-implanted electrode to a location internal to a patient body and near a blood vessel, the extravascularly-implanted electrode encircling the extravascular nerve tissue without encircling the blood vessel; receiving an electrical response signal in response to the electrical test signal; measuring, using a processor circuit, a vessel dimension of the blood vessel near the extravascularly-implanted electrode using the received electrical response signal; comparing, using a processor circuit, the measured vessel dimension to a reference vessel dimension to determine a vessel dimension change; outputting an indication of the determined vessel dimension change; and providing an electrostimulation signal directed from the extravascularly-implanted electrode toward the extravascular nerve tissue. - View Dependent Claims (17, 18, 19)
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20. An apparatus, comprising:
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an electrode configured to be extravascularly implanted in a cervical region, the extravascularly-implanted electrode adapted for encircling a vagus nerve near a carotid artery without encircling the carotid artery; an electrical energy delivery circuit configured to be coupled to the extravascularly-implanted electrode and configured to; provide a non-neurostimulating electrical test signal using the extravascularly-implanted electrode when the electrode encircles the vagus nerve without encircling the carotid artery; and provide a neurostimulating signal directed from the extravascularly-implanted electrode toward the vagus nerve when the electrode encircles the vagus nerve without encircling the carotid artery; a detector circuit configured to receive an electrical response signal in response to the non-neurostimulating electrical test signal; and a signal processor circuit, coupled to the electrical energy delivery circuit and the detector circuit, the signal processor circuit configured to; determine a radial blood vessel dimension of the carotid artery near the extravascularly-implanted electrode using the received electrical response signal; compare the determined radial blood vessel dimension to a reference radial blood vessel dimension to determine a radial blood vessel dimension change; determine at least one of a pulse transit time or a relative pulse pressure using information about the radial blood vessel dimension change; and output information about a patient health status using the at least one of the pulse transit time or the relative pulse pressure.
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Specification