Multiple vector fluid localization
First Claim
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1. A system comprising:
- an impedance measurement circuit configured to measure tissue impedance using a plurality of impedance vectors including first and second impedance vectors; and
a detector circuit communicatively coupled to the impedance measurement circuit, configured to generate a fluid status indicator using the measured tissue impedance including a relative measure between a change in first impedance measurements according to the first impedance vector and a change in second impedance measurements according to the second impedance vector, the fluid status indicator indicating fluid accumulation at a body location;
wherein the first impedance vector includes a first excitation vector for providing a first excitation signal, and a first response vector for sensing a first response to the first excitation signal, the first excitation vector being non-orthogonal to the first response vector; and
wherein the second impedance vector includes a second excitation vector for providing a second excitation signal, and a second response vector for sensing a second response to the second excitation signal, the second excitation vector being substantially orthogonal to the second response vector.
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Abstract
A differential or relative measurement between an orthogonal measurement vector and another measurement vector can be used to determine the location where fluid accumulation is occurring or the local change in such fluid accumulation. This can help diagnose or treat infection or hematoma or seroma at a pocket of an implanted cardiac rhythm management device, other implanted medical device, or prosthesis. It can also help diagnose or treat pulmonary edema, pneumonia, pulmonary congestion, pericardial effusion, pericarditis, pleural effusion, hemodilution, or another physiological condition.
44 Citations
20 Claims
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1. A system comprising:
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an impedance measurement circuit configured to measure tissue impedance using a plurality of impedance vectors including first and second impedance vectors; and a detector circuit communicatively coupled to the impedance measurement circuit, configured to generate a fluid status indicator using the measured tissue impedance including a relative measure between a change in first impedance measurements according to the first impedance vector and a change in second impedance measurements according to the second impedance vector, the fluid status indicator indicating fluid accumulation at a body location; wherein the first impedance vector includes a first excitation vector for providing a first excitation signal, and a first response vector for sensing a first response to the first excitation signal, the first excitation vector being non-orthogonal to the first response vector; and wherein the second impedance vector includes a second excitation vector for providing a second excitation signal, and a second response vector for sensing a second response to the second excitation signal, the second excitation vector being substantially orthogonal to the second response vector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method, comprising:
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measuring tissue impedance using a plurality of impedance vectors including first and second impedance vectors, including; measuring first tissue impedance according to a first impedance vector, including applying a first excitation signal to a first excitation vector and sensing a first response to the first excitation signal from a first response vector, the first excitation vector being non-orthogonal to the first response vector, the first excitation vector being non-orthogonal to the first response vector; and measuring second tissue impedance according to a different second impedance vector, including applying a second excitation signal to a second excitation vector and sensing a second response to the second excitation signal from a second response vector, the second excitation vector being substantially orthogonal to the second response vector; and generating a fluid status indicator using a relative measure between a change in the first impedance measurements and a change in the second impedance measurements, the fluid status indicator indicating fluid accumulation at a body location. - View Dependent Claims (17)
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18. A system, comprising:
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means for measuring tissue impedance using a plurality of impedance vectors, including means for measuring first tissue impedance according to a first impedance vector and means for measuring second tissue impedance according to a second impedance vector, wherein; the first impedance vector including a first excitation vector for providing a first excitation signal, and a first response vector for sensing a first response to the first excitation signal, the first excitation vector being non-orthogonal to the first response vector; and the second impedance vector includes a second excitation vector for providing a second excitation signal, and a second response vector for sensing a second response to the second excitation signal, the second excitation vector being substantially orthogonal to the second response vector; and means for generating a fluid status indicator using a relative measure between a change in the first impedance measurements and a change in the second impedance measurements, the fluid status indicator indicating fluid accumulation at a body location. - View Dependent Claims (19, 20)
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Specification