Impedance measurement apparatus for assessment of biomedical electrode interface quality
First Claim
1. Apparatus for assessing the electrical properties of an interface between a patient and electrodes applied to the patient, said apparatus comprising:
- a carrier signal source couplable to the electrodes, said carrier signal source receiving DC energization and AC energization and outputting two carrier signals comprising an AC signal with a DC offset, the two carrier signals being out of phase with each other by a pre-selected amount, one of said carrier signals being suppliable to a selected one of said electrodes, the other of said carrier signals being suppliable to others of said electrodes;
amplifier means comprising at least one amplifier each having a pair of inputs, one of said inputs being couplable to the selected one of the electrodes, the other input being couplable to another of said electrodes, said amplifier producing an output lead signal in which AC and DC offset characteristics result from the electrical properties of the patient interfaces at the electrodes; and
signal processing means coupled to said amplifier means and receiving said output lead signal of said amplifier, said signal processing means having means for obtaining and providing a first signal comprising the AC signal characteristics of the output lead signal and for providing a second signal comprising the DC characteristics in the output lead signal, said signal processing means having means employing said first signal to provide a first output indicative of the quality of an interface between the electrodes and the patient and said second signal to provide a second output indicative of the status of the connection between the electrodes and the patient.
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Accused Products
Abstract
Apparatus for assessing the electrical properties of patient-electrode interfaces has a carrier signal source injecting two carrier signals comprising an AC signal with a DC offset to the electrodes. The carrier signals are out of phase. The outputs from the electrodes are formed into electrocardiographic lead signals in a pre-amplifier circuit. Signal processing circuit is coupled to the pre-amplifier circuit and provides a first signal comprising the AC carrier signal contained in an ECG lead signal and a second signal containing a DC offset signal. The first and second signals are provided to a microprocessor to obtain an output indicative of the electrical properties of electrode interfaces for the ECG lead signal.
22 Citations
20 Claims
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1. Apparatus for assessing the electrical properties of an interface between a patient and electrodes applied to the patient, said apparatus comprising:
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a carrier signal source couplable to the electrodes, said carrier signal source receiving DC energization and AC energization and outputting two carrier signals comprising an AC signal with a DC offset, the two carrier signals being out of phase with each other by a pre-selected amount, one of said carrier signals being suppliable to a selected one of said electrodes, the other of said carrier signals being suppliable to others of said electrodes; amplifier means comprising at least one amplifier each having a pair of inputs, one of said inputs being couplable to the selected one of the electrodes, the other input being couplable to another of said electrodes, said amplifier producing an output lead signal in which AC and DC offset characteristics result from the electrical properties of the patient interfaces at the electrodes; and signal processing means coupled to said amplifier means and receiving said output lead signal of said amplifier, said signal processing means having means for obtaining and providing a first signal comprising the AC signal characteristics of the output lead signal and for providing a second signal comprising the DC characteristics in the output lead signal, said signal processing means having means employing said first signal to provide a first output indicative of the quality of an interface between the electrodes and the patient and said second signal to provide a second output indicative of the status of the connection between the electrodes and the patient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. Apparatus for assessing the electrical properties of an interface between a patient and electrodes applied to the patient, said apparatus comprising:
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a carrier signal source couplable to the electrodes, said carrier signal source receiving DC energization and AC energization and outputting two carrier signals comprising an AC signal with a DC offset, the two carrier signals being out of phase with each other by a pre-selected amount, one of said carrier signals being suppliable to a selected one of said electrodes, the other of said carrier signals being suppliable to others of said carrier signals being suppliable to others of said electrodes wherein the carrier signal source includes means for selectively removing AC energization from said carrier signals; amplifier means comprising at least one amplifier each having a pair of inputs, one of said inputs being couplable to the selected one of the electrodes, the other input being couplable to another of said electrodes, said amplifier producing an output lead signal which AC and DC offset characteristics result from the electrical properties of the patient interfaces at the electrodes; and signal processing means coupled to said amplifier means and receiving said output lead signal of said amplifier, said signal processing means having means for obtaining and providing a first signal comprising the AC signal characteristics of the output lead signal and for providing a second signal comprising the DC characteristics in the output lead signal, said signal processing means having means employing said first and second signals to provide an output indicative of the electrical properties of an interface between a patient and electrodes applied to the patient.
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17. Apparatus for assessing the electrical properties of interfaces between a patient and electrodes applied to the patient, said apparatus comprising:
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a carrier signal source couplable to the electrodes the carrier signal source receiving DC energization and AC energization and outputting a carrier signal including DC energization; the carrier signal being applied to at least one of the electrodes; a switch coupled to the carrier signal source and to the AC energization, the switch being operable to selectively include AC energization in the carrier signal; a signal processor in communication with the electrodes and receiving from the electrodes a signal in which DC offset characteristics and selectively AC offset characteristics result from the electrical properties of the interfaces between the patient and the electrodes, the signal processor providing a first signal comprising the AC offset characteristics and a second signal comprising the DC offset characteristics, the signal processor employing the first signal to provide a first output indicative of the quality of the interfaces between the electrodes and the patient and employing the second signal to provide a second output indicative of the status of the correction between the electrodes and the patient. - View Dependent Claims (18, 19, 20)
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Specification