EP0457604A2
Expired / Lapsed
EP
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Impedance-based defibrillator
Assignee: HP Inc
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Filing: 1991-05-17
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Granted: —
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Expires: 2011-05-17
Abstract
Abstract Impedance-normalized delivered energy is used as a control parameter in a defibrillation methodology and can be selected to yield the highest probability of successful defibrillation while minimizing the risk of damage to the myocardium and nerve system. This control parameter is essentially independent of patient transthoracic impedance and of discharge pulse waveform and duration, thereby making it advantageous as a standard on which a universal defibrillation protocol may be based.
Inventors
- 👤 Martin G. Rockwell
- 👤 Francis M. Charbonnier
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 15:15
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/18; A61N1/32; A61N1/38; A61N1/39; A61N1/3925; A61N1/3937
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
121 words
A defibrillator (10) for providing a defibrillation pulse to a patient to restore normal cardiac rhythm, comprising: an energy storage device (12); impedance correction means (39) for establishing a desired value of impedance corrected delivered energy (E d /Z p ); means for measuring a transthoracic impedance (Z p ) of the patient; means for determining a target amount of energy required by the energy storage device to provide the desired value of impedance-corrected delivered energy (E d /Z p ) to a patient having the measured value of transthoracic impedance (Z); energizing means for providing the target amount of energy to the energy storage device; and de-energizing means for transferring energy stored in the energy storage device to the patient.
Claim 2
Dependent Claim
60 words
A defibrillator according to claim 1 in which: the energizing means further includes means for providing a second amount of energy in addition to the target amount to the energy storage device; the de-energizing means further includes means for removing energy from the energy storage device until the target level is reached, prior to transferring stored energy to the patient.
Claim 3
Dependent Claim
43 words
A defibrillator according to claim 2 in which: the energizing means further includes means for providing a third amount of energy in addition to the second amount of energy to the energy storage device, prior to measuring the transthoracic impedance of the patient.
Claim 4
Dependent Claim
39 words
A defibrillator according to any one of claims 1 to 3, in which the impedance correction means establishes the desired value of impedance corrected delivered energy (E d /Z p ) without reference to particular characteristics of the patient.
Claim 5
Dependent Claim
19 words
A defibrillator according to claim 4 in which the desired value of impedance corrected delivered energy is 3 Joules/ohm.
Claim 6
Dependent Claim
67 words
A defibrillator according to any one of claims 1 to 5, in which the energizing means further includes means for repeating the provision of the target amount of energy to the energy storage device and the de-energizing means further includes means for repeating the transfer of energy from the energy storage device if the patient's normal cardiac rhythm is not restored by the first transfer of energy.
Claim 7
Dependent Claim
27 words
A defibrillator according to claim 6, in which the target amount of energy is 5 Joules/ohm for the repeated provision of energy to the energy storage device.
Claim 8
Dependent Claim
74 words
A defibrillator according to any one of claims 1 to 7, further including means for measuring the energy storage device to ascertain the value of a physically measurable parameter required to store the target amount of energy in the energy storage device; and in which the energizing and de-energizing means further include means for providing energy to or from the energy storage device until the physically measurable parameter equals the target amount of energy.
Claim 9
Dependent Claim
113 words
A defibrillator (10) for providing a defibrillation pulse to a patient to restore normal cardiac rhythm, comprising: a capacitor (12); means (39) for establishing a desired value of impedance-corrected delivered energy (E d /Z p ); means (24) for measuring a transthoracic impedance (Z p ) of the patient; means (40) for determining the voltage to which the capacitor must be charged to provide the desired value of impedance-corrected delivered energy to a patient having the transthoracic impedance measured; means (18, 20, 22, 42, 48, 50) for providing charge to or from the capacitor until the voltage thereacross equals the calculated voltage; and means (54) for discharging the charged capacitor through the patient.
References Cited (Backward Citations)
No citation records indexed.
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