DEFIBRILLATOR

• US 3,886,950 A
• Filed: 10/01/1973
• Issued: 06/03/1975
• Est. Priority Date: 10/01/1973
• Status: Expired due to Term

• Current Assignee: Donald C. Hancock, Donald C. Ukkestad, Donley J. Valiquette
• Original Assignee: Donald C. Hancock, Donald C. Ukkestad, Donley J. Valiquette
• Inventors: Ukkestad, Donald C., Hancock, Donald C., Valiquette, Donley J.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/402,401
• Time in Patent Office: 610 Days
• Field of Search: 128/419D,419R
• US Class Current: 607/5
• CPC Class Codes: A61N 1/3937 Monitoring output parameters

Abstract

A defibrillator is disclosed which regulates the magnitude of a current pulse delivered to a patient in accordance with a selected value of current and which quickly terminates the current pulse when the measured energy delivered to the patient equals a selected value. Current regulation is accomplished by circuitry which compares current actually flowing through the patient with the selected value and which utilizes the results of such comparison to sequentially discharge a plurality of capacitors serially coupled to the patient electrodes. Further circuity multiplies the current through the patient by the voltage measured across the patient to determine power with the resulting signal being integrated relative to time to indicate delivered energy. When the delivered energy equals the selected value of energy, the electrodes are shunted by circuitry which terminates the current pulse to the patient and which discharges all capacitors not already discharged.

Claims

1. A defibrillator for delivering electrical current to a plurality of patient electrodes comprising:

a plurality of electrodes;

a plurality of capacitors coupled to the electrodes;

means coupled to the capacitors and including a power source for charging the capacitors;

means coupled to the capacitors for initiating discharge of at least one of the capacitors to initiate generation of a current pulse; and

means coupled to the capacitors and responsive to the initiating of discharge of at least one of the capacitors for subsequently discharging at least one other capacitor during the discharge of said at least one of the capacitors to continue the generation of the current pulse.

2. The invention defined in claim 1, wherein the means for subsequently discharging at least one other capacitor during the discharge cycle comprises means for initiating discharge of said at least one other capacitor when the magnitude of the current pulse as provided by discharge of said at least one of the capacitors decreases to a predetermined minimum value.

3. The invention defined in claim 1, further including means for monitoring delivered electrical energy at the electrodes, a shunt lead coupled in parallel with the electrodes and means coupled to the monitoring means for discharging all capacitors not already discharged through the shunt lead whenever the delivered electrical energy reaches a selected value.

4. A defibrillator for delivering electrical current to a plurality of patient electrodes comprising:

a plurality of electrodes;

a plurality of capacitors coupled to the electrodes;

means coupled to the capacitors including a power source for charging the capacitors;

means coupled to the capacitors for initiating discharge of at least one of the capacitors to initiate a discharge cycle;

means coupled to the capacitors and responsive to the initiating of a discharge cycle and the initiating of discharge of at least one of the capacitors for subsequently discharging at least one of the capacitors during the discharge cycle to provide a controlled amount of electrical current to the electrodes;

means for monitoring electrical current at the electrodes;

means for providing a reference; and

means for comparing the monitored electrical current with the reference to provide a current deficiency signal, the means for subsequently discharging at least one other capacitor during the discharge cycle performing discharge of at least one other capacitor in response to the current deficiency signal.

5. A defibrillator comprising:

chargeable means;

means for selectively charging the chargeable means;

means for selectively initiating discharge of the chargeable means to provide a current to a patient;

means for measuring current flowing through the patient;

means for providing a reference signal representing a desired value of current through the patient;

means responsive to the measured current flowing through the patient and to the reference signal for generating a control signal representing differences between the measured current flowing through the patient and the reference signal; and

means responsive to the control signal for controlling discharge of the chargeable means in accordance with the control signal to regulate the current flowing through the patient.

6. The invention defined in claim 5, wherein tHe chargeable means comprises a plurality of capacitors and the means for controlling discharge comprises means responsive to the control signal for generating pulses representing the difference between the measured current flowing through the patient and the reference signal and means responsive to the generated pulses for sequentially discharging the capacitors in accordance with the number of pulses generated.

7. A defibrillator for delivering current pulses to a patient via a pair of electrodes comprising:

a pair of electrodes;

a plurality of capacitors coupled to the electrodes;

means for selectively charging the capacitors;

means for discharging at least one capacitor to initiate the delivery of a current pulse to the patient;

means for measuring the magnitude of the current pulse delivered to the patient;

means for providing a desired value of current magnitude;

means for comparing the measured magnitude of the current pulse with the desired value of current magnitude to provide a current error signal representing the difference therebetween;

means responsive to the current error signal and coupled to the capacitors for selectively discharging the capacitors in accordance with the value of the current error signal to maintain the magnitude of the current pulse substantially equal to the desired value of current magnitude;

means for measuring the electrical energy delivered to the patient via the current pulse;

means for comparing the measured electrical energy with the desired value of energy to provide a pulse termination signal whenever the measured electrical energy is substantially equal to the desired value of energy; and

means responsive to the pulse termination signal for terminating the current pulse at the electrodes.

8. The invention defined in claim 7, wherein the means for selectively discharging the capacitors includes a plurality of silicon controlled rectifiers, means for coupling each of the silicon controlled rectifiers between a different one of the capacitors and one of the electrodes, and means for selectively gating each of the silicon controlled rectifiers.

9. The invention defined in claim 8, further including a plurality of serially coupled diodes coupled between the electrodes, and wherein each of the capacitors is coupled in parallel with a different one of the plurality of serially coupled diodes and the means for selectively discharging the capacitors includes a plurality of silicon controlled rectifiers, each of the silicon controlled rectifiers being coupled between a different one of the capacitors and an associated one of the diodes, and means coupled to selectively bias the silicon controlled rectifiers into conduction in response to the current error signal.

10. The invention defined in claim 7, wherein the means for selectively discharging the capacitors includes means for generating a plurality of discharge signals, the number of which is dependent upon the value of the current error signal, and means responsive to the discharge signals for discharging a different capacitor in response to each separate discharge signal.

11. The invention defined in claim 7, wherein the means for measuring the electrical energy delivered to the patient includes means for measuring the voltage across the electrodes, means responsive to the measured voltage and the measured current for computing measured power, and means responsive to the measured power for computing measured energy.