Monitoring thoracic fluid changes
First Claim
1. A method for performing a measurement related to a volume of fluid in a region inside a thorax of a body, comprising:
- injecting an electrical current between first and second internal electrodes positioned such that a portion of the injected current flows through at least a portion of the region, the internal electrodes being implanted in the body;
measuring a voltage between first and second external electrodes, the measured voltage being induced by the injected current, the first and second external electrodes being attached to an external surface of the skin of the body; and
calculating a first impedance by taking the ratio of the measured voltage and the injected current, wherein the calculated impedance is related to the volume of fluid in the region.
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Abstract
Changes in fluid volume in a thoracic region, such as the lung, are detected by internally injecting a current through the region, detecting an induced voltage on the skin of the patient, and calculating an impedance value. A method for performing such a measurement includes injecting an electrical current between first and second internal electrodes that are implanted in the body and that are positioned such that a portion of the injected current flows through at least a portion of the region. The method also includes measuring a voltage between first and second external electrodes attached to an external surface of the skin of the body. The measured voltage is induced by the injected current. The method also includes calculating an impedance by taking the ratio of the measured voltage and the injected current, wherein the calculated impedance is related to the volume of fluid in the region.
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Citations
43 Claims
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1. A method for performing a measurement related to a volume of fluid in a region inside a thorax of a body, comprising:
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injecting an electrical current between first and second internal electrodes positioned such that a portion of the injected current flows through at least a portion of the region, the internal electrodes being implanted in the body; measuring a voltage between first and second external electrodes, the measured voltage being induced by the injected current, the first and second external electrodes being attached to an external surface of the skin of the body; and calculating a first impedance by taking the ratio of the measured voltage and the injected current, wherein the calculated impedance is related to the volume of fluid in the region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. An apparatus for performing a measurement related to a volume of fluid in a region inside a thorax of a body, comprising:
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a receiver that receives information about an electrical current injected between first and second internal electrodes adapted to be positioned such that a portion of the injected current flows through at least a portion of the region, the received information being telemetered from a device that injects the current, the device and the internal electrodes for being implanted in the body; an interface that receives a voltage signal detected by first and second external electrodes adapted to be attached to an external surface of the skin of the body, the detected voltage being induced by the injected current; and a processing unit that determines the fluid volume in the region by calculating a first impedance from the voltage signal and the received information about the injected current. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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Specification