Sensitivity and specificity of pulmonary edema detection when using transthoracic impedance
First Claim
1. A system comprising:
- an implantable thoracic impedance measurement circuit, adapted to sense a thoracic impedance signal from a subject;
a processor, coupled with the thoracic impedance measurement circuit to accept the thoracic impedance signal; and
a statistical analysis module adapted to compute at least one statistical parameter regarding a variability of the thoracic impedance signal, wherein the processor is adapted to determine a pulmonary edema indication using the at least one statistical parameter and the thoracic impedance signal.
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Abstract
This patent document discusses, among other things, systems, devices, and methods for enhancing detection of pulmonary edema using, in addition to thoracic impedance, one or a combination of: physiologic information about a subject, at least one statistical parameter, a user-programmable detection level, at least one parameter associated with a previous pulmonary edema event, and patient symptom information about the subject. In one example, a (base) thoracic impedance threshold is modified to an adjusted thoracic impedance threshold. The adjusted thoracic impedance threshold provides an increased sensitivity of pulmonary edema detection as compared to the base thoracic impedance threshold. In another example, an alert is provided to a subject, a caregiver, or other user based on a pulmonary edema indication determined by the present systems, devices, and methods. In a further example, a therapy (provided to the subject) is adjusted or initiated in response to the pulmonary edema indication.
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Citations
28 Claims
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1. A system comprising:
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an implantable thoracic impedance measurement circuit, adapted to sense a thoracic impedance signal from a subject;
a processor, coupled with the thoracic impedance measurement circuit to accept the thoracic impedance signal; and
a statistical analysis module adapted to compute at least one statistical parameter regarding a variability of the thoracic impedance signal, wherein the processor is adapted to determine a pulmonary edema indication using the at least one statistical parameter and the thoracic impedance signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method comprising:
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implantably sensing a thoracic impedance signal from the thorax of a subject;
computing at least one statistical parameter regarding a variability of the thoracic impedance signal; and
determining a pulmonary edema indication using the at least one statistical parameter and the thoracic impedance signal. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A system comprising:
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a memory storage device, adapted to store at least one previous parameter associated with a previous pulmonary edema episode, the at least one previous parameter selected from a previous parameter group consisting essentially of;
a previous thoracic impedance, a previous physiologic parameter, a previous environmental parameter, a previous compliance parameter, and a previous patient symptom parameter;
a parameter collection device, adapted to sense or receive at least one present parameter about a subject, the at least one present parameter selected from a present parameter group consisting essentially of;
a present physiologic parameter, a present environmental parameter, a present compliance parameter, and a present patient symptom parameter;
an implantable thoracic impedance measurement circuit, adapted to sense a present thoracic impedance signal from the subject; and
a processor, coupled with the memory storage device to accept the at least one previous parameter, coupled with the parameter collection device to accept the at least one present parameter, and coupled with the thoracic impedance measurement circuit to accept the present thoracic impedance signal, wherein the processor is adapted to determine a pulmonary edema indication using one or a combination of;
the at least one previous parameter, the at least one present parameter, and the present thoracic impedance signal. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. A method comprising:
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implantably sensing a present thoracic impedance signal from the thorax of a subject;
storing at least one parameter associated with a previous pulmonary edema episode, the at least one previous parameter selected from a previous parameter group consisting essentially of one or more of;
a previous thoracic impedance, a previous physiologic parameter, a previous environmental parameter, a previous compliance parameter, and a previous patient symptom parameter;
sensing or receiving at least one present parameter about the subject, the at least one present parameter selected from a present parameter group consisting essentially of one or more of;
a present physiologic parameter, a present environmental parameter, a present compliance parameter, and a present patient symptom parameter; and
determining a pulmonary edema indication using one or a combination of;
the at least one previous parameter, the at least one present parameter, and the present thoracic impedance signal. - View Dependent Claims (25, 26, 27, 28)
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Specification