Procedure for measuring a patient's impedance
First Claim
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1. A method for measuring a patient'"'"'s impedance comprising the steps of:
- connecting first and second electrodes to the patient at spaced locations on the skin of the patient;
connecting the second electrode to ground through a grounding impedance;
supplying a periodically varying measuring signal to the first electrode to provide an electrical signal through the patient'"'"'s impedance to the second electrode and the grounding impedance, a characteristic of the electrical signal being determined by the impedance of the patient; and
measuring an electrical characteristic at the grounding impedance resulting from the provision of the electrical signal to the grounding impedance to ascertain the impedance of the patient.
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Abstract
The present invention relates to a procedure for measuring a patient'"'"'s impedance. Based on the impedance, it is possible to monitor the patient'"'"'s respiration and/or blood circulation. In the procedure, a plurality of electrodes (1a, 1b; 1d, 2; 2a) are connected to be patient and the changes in the impedance relationships between the electrodes (1a, 1b, 2) are measured. The invention makes it possible to use the same measuring conductors and measuring electrodes for impedance measurement as are used in ECG measurement.
43 Citations
38 Claims
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1. A method for measuring a patient'"'"'s impedance comprising the steps of:
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connecting first and second electrodes to the patient at spaced locations on the skin of the patient; connecting the second electrode to ground through a grounding impedance; supplying a periodically varying measuring signal to the first electrode to provide an electrical signal through the patient'"'"'s impedance to the second electrode and the grounding impedance, a characteristic of the electrical signal being determined by the impedance of the patient; and measuring an electrical characteristic at the grounding impedance resulting from the provision of the electrical signal to the grounding impedance to ascertain the impedance of the patient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for measuring impedance characteristics of a patient comprising the steps of:
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connecting first, second, and third electrodes to the patient at spaced locations on the skin of the patient; connecting the third electrode to ground through a grounding impedance; supplying a periodically varying measuring signal to the first electrode to provide a first electrical signal to the grounding impedance, a characteristic of the first electrical signal being determined by an impedance of the patient; supplying a periodically varying measuring signal to the second electrode having a predetermined phase relationship to the signal supplied to the first electrode to provide a second electrical signal to the grounding impedance, a characteristic of the second electrical signal being determined by an impedance of the patient; and measuring an electrical characteristic produced at the grounding impedance by the provision of the first and second electrical signals to the grounding impedance to ascertain the impedance characteristics of the patient. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. A method for measuring impedance characteristics of a patient comprising the steps of:
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connecting first and second electrodes to the patient at spaced locations on the skin of the patient; connecting the first electrode to ground through a grounding impedance; supplying a periodically varying measuring signal to the first electrode to provide an electrical signal to the first electrode; and measuring an electrical characteristic produced at the second electrode to ascertain the impedance characteristics of the patient. - View Dependent Claims (37)
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38. A method for measuring impedance characteristics of a patient comprising the steps of:
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connecting first and second electrodes to the patient at spaced locations on the skin of the patient; connecting a third electrode on the skin of the patient to form an electrocardiographic common electrode; providing a common mode drive signal to said third electrode; supplying a periodically varying impedance measuring signal to the common mode drive signal; and measuring an electrical property produced at at least one of said first and second electrodes to ascertain the impedance characteristics of the patient.
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Specification