Detection of reduced defibrillation pad contact
First Claim
1. A life support device, comprising:
- a pair of electrodes configured to be attached to a skin of a subject;
a therapy interface electrically coupled to the pair of electrodes; and
a transthoracic impedance monitor electrically coupled to the therapy interface, the transthoracic impedance monitor being configuredto monitor transthoracic impedance parameters of a transthoracic impedance signal between the pair of electrodes over time, wherein the transthoracic impedance signal has a high frequency waveform component that varies with a frequency of CPR chest compressions, and wherein the transthoracic impedance parameters include at least one of a slope of the high frequency waveform component of the transthoracic impedance signal, a shape of the high frequency waveform component of the transthoracic impedance signal, and a relative energy content of the high frequency waveform component of the transthoracic impedance signal at a fundamental frequency of the transthoracic impedance signal and/or at a harmonic of the fundamental frequency of the transthoracic impedance signal,to establish baseline levels of the transthoracic impedance parameters,to detect whether changes over time in at least one transthoracic impedance parameter exceeds a corresponding baseline level by a threshold,to determine that at least one electrode of the pair of electrodes is losing electrical contact with the skin of the subject in response to detecting that the changes in the at least one transthoracic impedance parameter exceeds the corresponding baseline level by the threshold, andto issue an alert in response to a determination that the at least one electrode of the pair of electrodes is losing electrical contact with the skin of the subject.
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Accused Products
Abstract
A system and method of detecting a loss of electrical contact between a pair of electrodes that are electrically coupled to skin of a subject. The method includes monitoring parameters of a transthoracic impedance between the pair of electrodes in at least one of a low frequency regime and a high frequency regime, detecting an occurrence of chest compressions based on a signal indicative of chest compressions, establishing baseline levels of the parameters in at least one of the low and high frequency regimes, detecting whether changes in at least one parameter exceeds the baseline level by a threshold, determining that at least one electrode of the pair of electrodes is losing electrical contact with the skin responsive to the at least one parameter exceeding the baseline level by the threshold, and issuing an alert in response to a determination that the at least one electrode is losing electrical contact.
13 Citations
18 Claims
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1. A life support device, comprising:
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a pair of electrodes configured to be attached to a skin of a subject; a therapy interface electrically coupled to the pair of electrodes; and a transthoracic impedance monitor electrically coupled to the therapy interface, the transthoracic impedance monitor being configured to monitor transthoracic impedance parameters of a transthoracic impedance signal between the pair of electrodes over time, wherein the transthoracic impedance signal has a high frequency waveform component that varies with a frequency of CPR chest compressions, and wherein the transthoracic impedance parameters include at least one of a slope of the high frequency waveform component of the transthoracic impedance signal, a shape of the high frequency waveform component of the transthoracic impedance signal, and a relative energy content of the high frequency waveform component of the transthoracic impedance signal at a fundamental frequency of the transthoracic impedance signal and/or at a harmonic of the fundamental frequency of the transthoracic impedance signal, to establish baseline levels of the transthoracic impedance parameters, to detect whether changes over time in at least one transthoracic impedance parameter exceeds a corresponding baseline level by a threshold, to determine that at least one electrode of the pair of electrodes is losing electrical contact with the skin of the subject in response to detecting that the changes in the at least one transthoracic impedance parameter exceeds the corresponding baseline level by the threshold, and to issue an alert in response to a determination that the at least one electrode of the pair of electrodes is losing electrical contact with the skin of the subject. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of detecting a loss of electrical contact between at least one electrode of a pair of electrodes that are electrically coupled to a skin of a subject, comprising acts of:
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monitoring transthoracic impedance parameters of a transthoracic impedance signal between the pair of electrodes, wherein the transthoracic impedance signal has a high frequency waveform component that varies with a frequency of CPR chest compressions, and wherein the transthoracic impedance parameters include at least one of a slope of the high frequency waveform component of the transthoracic impedance signal, a shape of the high frequency waveform component of the transthoracic impedance signal, and a relative energy content of the high frequency waveform component of the transthoracic impedance signal at a fundamental frequency of the transthoracic impedance signal and/or at a harmonic of the fundamental frequency of the transthoracic impedance signal; establishing baseline levels of the transthoracic impedance parameters; detecting whether changes in at least one transthoracic impedance parameter exceeds the a corresponding baseline level by a threshold; determining, prior to loss of electrical contact between the at least one electrode of the pair of electrodes and the skin of the subject, that the at least one electrode of the pair of electrodes is losing electrical contact with the skin of the subject in response to the at least one transthoracic impedance parameter exceeding the corresponding baseline level by the threshold; and issuing an alert in response to a determination that the at least one electrode of the pair of electrodes is losing electrical contact with the skin of the subject. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A life support device, comprising:
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a pair of electrodes configured to be attached to a skin of a subject; a therapy interface electrically coupled to the pair of electrodes; and a transthoracic impedance monitor electrically coupled to the therapy interface, the transthoracic impedance monitor being configured to monitor transthoracic impedance parameters of a transthoracic impedance signal between the pair of electrodes, wherein the transthoracic impedance signal has a high frequency waveform component that varies with a frequency of CPR chest compressions, and wherein the transthoracic impedance parameters include at least one of a slope of the high frequency waveform component of the transthoracic impedance signal, a shape of the high frequency waveform component of the transthoracic impedance signal, and a relative energy content of the high frequency waveform component of the transthoracic impedance signal at a fundamental frequency of the transthoracic impedance signal and/or at a harmonic of the fundamental frequency of the transthoracic impedance signal, to establish baseline levels of the transthoracic impedance parameters, to detect whether changes in at least one transthoracic impedance parameter exceeds a corresponding baseline level by a threshold, to determine that at least one electrode of the pair of electrodes is losing electrical contact with the skin of the subject in response to detecting that the changes in the at least one transthoracic impedance parameter exceeds the corresponding baseline level by the threshold, and to issue an alert in response to a determination that the at least one electrode of the pair of electrodes is losing electrical contact with the skin of the subject.
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Specification