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US4574810A
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Automatic threshold defibrillator
Assignee: Individual
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Filing: 1984-10-05
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Granted: 1986-03-11
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Expires: 2004-10-05
Abstract
Abstract A defibrillator which will automatically ascertain the transthoracic resistance of the patient and then automatically apply a defibrillation shock according to the transthoracic resistance and an amperes per ohm factor.
Inventors
- 👤 Bruce B. Lerman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:28
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/18; A61N1/32; A61N1/38; A61N1/39; A61N1/3925; A61N1/3937; A61N1/36; A61N1/362; A61N1/365; A61N1/36514; A61N1/36521
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
103 words
A method of determining an optimum threshold level of peak defibrillation current to be applied to the chest of a particular patient by means of a defibrillator in order to correct ventricular fibrillation, and comprising the steps of: (a) applying a low amplitude exploration current from electrodes forming part of said defibrillator to said chest and sensing voltage developed thereby across said electrodes; (b) calculating transthoracic resistance from said exploration current and response voltage; and (c) multiplying said transthoracic resistance by an ampere per ohm factor, the resulting amperage being the level of peak current to be applied to the patient for defibrillation.
Claim 2
Independent Claim
103 words
A method of determining an optimum threshold level of peak defibrillation current to be applied to the chest of a particular patient by means of a defibrillator in order to correct ventricular fibrillation, and comprising the steps of: (a) applying a low amplitude exploration current from electrodes forming part of said defibrillator to said chest and sensing voltage developed thereby across said electrodes; (b) calculating transthoracic resistance from said exploration current and response voltage; and (c) multiplying said transthoracic resistance by an ampere per ohm factor, the resulting amperage being the level of peak current to be applied to the patient for defibrillation.
Claim 3
Dependent Claim
19 words
A method as in claim 1 wherein said factor is at least about 0.9 amperes per ohm of resistance.
Claim 4
Dependent Claim
21 words
A method as in claim 1 wherein a frequency of said exploration current is in the range of about 20-60 kHz.
Claim 5
Independent Claim
98 words
A method of defibrillating a patient having ventricular fibrillation comprising the steps of: (a) applying a low amplitude exploration current from electrodes forming part of a defibrillator to the chest of said patient and sensing voltage developed thereby across said electrodes; (b) calculating transthoracic resistance from said exploration current and response voltage; (c) multiplying said transthoracic resistance by an amperes per ohm factor; (d) charging the defibrillator capacitor according to said resulting amperage to create the capacitor discharge voltage generative of said resulting amperage as the level of peak current; and (e) discharging said defibrillator capacitor and defibrillating.
Claim 6
Independent Claim
98 words
A method of defibrillating a patient having ventricular fibrillation comprising the steps of: (a) applying a low amplitude exploration current from electrodes forming part of a defibrillator to the chest of said patient and sensing voltage developed thereby across said electrodes; (b) calculating transthoracic resistance from said exploration current and response voltage; (c) multiplying said transthoracic resistance by an amperes per ohm factor; (d) charging the defibrillator capacitor according to said resulting amperage to create the capacitor discharge voltage generative of said resulting amperage as the level of peak current; and (e) discharging said defibrillator capacitor and defibrillating.
Claim 7
Dependent Claim
37 words
A method as in claim 4 further comprising the steps of: calculating transthoracic resistance from the peak defibrillating current and capacitor discharge voltage; and displaying the values of both transthoracic resistances and of the peak defibrillation current.
Claim 8
Dependent Claim
19 words
A method as in claim 4 wherein said factor is at least about 0.9 amperes per ohm of resistance.
Claim 9
Independent Claim
106 words
An apparatus for determining an optimum threshold level of peak defibrillation current to be applied to the chest of a particular patient by means of a defibrillator in order to correct for ventricular fibrillation and comprising: (a) means for applying a low amplitude exploration current from electrodes forming part of said defibrillator to said chest and sensing voltage developed across said electrodes; (b) means for calculating transthoracic resistance from said exploration current and response voltage; and (c) means for multiplying said transthoracic resistance by an ampere per ohm factor, the resulting amperage being the level of peak current to be applied to the patient for defibrillation.
Claim 10
Independent Claim
106 words
An apparatus for determining an optimum threshold level of peak defibrillation current to be applied to the chest of a particular patient by means of a defibrillator in order to correct for ventricular fibrillation and comprising: (a) means for applying a low amplitude exploration current from electrodes forming part of said defibrillator to said chest and sensing voltage developed across said electrodes; (b) means for calculating transthoracic resistance from said exploration current and response voltage; and (c) means for multiplying said transthoracic resistance by an ampere per ohm factor, the resulting amperage being the level of peak current to be applied to the patient for defibrillation.
Claim 11
Dependent Claim
19 words
An apparatus as in claim 7 wherein said factor is at least about 0.9 amperes per ohm of resistance.
Claim 12
Independent Claim
140 words
An apparatus for defibrillating a patient having ventricular fibrillation comprising: means for applying a low amplitude exploration current from electrodes forming part of a defibrillator to the chest of said patient and sensing voltage developed thereby across said electrodes; means for calculating transthoracic resistance from said exploration current and response voltage; means for multiplying said transthoracic resistance by an ampere per ohm factor, the resulting amperage being the level of defibrillation peak current applied to said chest via said electrodes during subsequent defibrillation; and defibrillator means adapted to apply an electrode voltage sufficient to provide said defibrillation peak current; said defibrillator means further comprising a capacitor and a charging means therefor forming part of the defibrillator means, the capacitor charging means being controlled so as to charge the capacitor to the voltage which provides said level of defibrillation peak current.
Claim 13
Independent Claim
140 words
An apparatus for defibrillating a patient having ventricular fibrillation comprising: means for applying a low amplitude exploration current from electrodes forming part of a defibrillator to the chest of said patient and sensing voltage developed thereby across said electrodes; means for calculating transthoracic resistance from said exploration current and response voltage; means for multiplying said transthoracic resistance by an ampere per ohm factor, the resulting amperage being the level of defibrillation peak current applied to said chest via said electrodes during subsequent defibrillation; and defibrillator means adapted to apply an electrode voltage sufficient to provide said defibrillation peak current; said defibrillator means further comprising a capacitor and a charging means therefor forming part of the defibrillator means, the capacitor charging means being controlled so as to charge the capacitor to the voltage which provides said level of defibrillation peak current.
Claim 14
Dependent Claim
38 words
An apparatus as in claim 9 further comprising: means for calculating transthoracic resistance from the peak defibrillating current and said discharge voltage; and means for displaying the value of both transthoracic resistances and of the peak defibrillation current.
Claim 15
Dependent Claim
19 words
An apparatus as in claim 9 wherein said factor is at least about 0.9 amperes per ohm of resistance.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-10 | 1989-09-09 | 1990-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-10 | 1993-09-09 | 1994-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-10 | 1997-09-09 | 1998-03-11 | $7700.00 | Window Closed / Lapsed |