Cardiac defibrillator with movable contact switch

• US 5,237,989 A
• Filed: 04/04/1991
• Issued: 08/24/1993
• Est. Priority Date: 04/04/1991
• Status: Expired due to Term

• Current Assignee: Creditanstalt-Bankverein (Unicredit SPA)
• Original Assignee: Physio-Control Incorporated (Stryker Corporation)
• Inventors: Szyperski, Joseph E., Morgan, Carlton B.
• Primary Examiner(s): Howell, Kyle L.
• Assistant Examiner(s): SCHAETZLE, KENNEDY
• Application Number:
  US07/681,347
• Time in Patent Office: 873 Days
• Field of Search: 128/419 D, 128/419 B, 128/419 R, 128/419 P, 128/419 PS
• US Class Current: 607/5
• CPC Class Codes: A61N 1/3904 External heart defibrillators [EHD]
• CPC Class Codes: A61N 1/3912 Output circuitry therefor, e.g. switches

Abstract

Disclosed is a cardiac defibrillator for providing a cardiac defibrillation pulse to a patient. The defibrillator comprises a switch contact (14) mounted on a movable switch (10) that moves between a charge position and a discharge position. In the charge position, the switch contact is coupled to a high-voltage battery (22) in order to provide a charge to an energy storage capacitor (30). When the movable switch is released from the charge position, the switch contact engages an electrode contact (32) and a defibrillation pulse flows into a patient (40). The duration of the cardiac defibrillation pulse can be varied by changing the length of time that the switch contact remains engaged with electrode contact. Also disposed within the switch contact path is a discharge contact (42), which is connected to a discharge resistor (48). When the movable switch is in a discharge position, the switch contact is engaged with the discharge contact thereby allowing the discharge resistor to dissipate charge from the energy storage capacitor. A spring (16) is connected to the movable switch in order to rotate it between the charge and discharge positions.

Claims

1. A cardiac defibrillator for delivering a cardiac defibrillation pulse to a patient comprising:

an electrical energy source;

an energy storage capacitor for storing an electrical charge from the electrical energy source;

a movable switch capable of moving between a charge position and a discharge position;

a first electrical contact connected to the movable switch such that the first electrical contact moves in a contact path as the movable switch moves between the charge and discharge positions, the first electrical contact being electrically coupled to the energy storage capacitor; and

a second electrical contact disposed within the contact path and connectable to means for delivering the cardiac defibrillation pulse to the patient, the second electrical contact selected from a plurality of contacts, each having a different contact length, wherein the cardiac defibrillation pulse is delivered to the patient when the first and second electrical contacts are engaged, the duration of the cardiac defibrillation pulse being variable by changing the contact length of the second electrical contact that is disposed in the contact path thereby varying the length of time that the first and second electrical contacts are engaged.

3. The cardiac defibrillator as in claim 1, further comprising a battery contact disposed within the contact path such that the energy storage capacitor is coupled to the electrical energy source when the movable switch is in the charge position.

4. The cardiac defibrillator as in claim 1, wherein the movable switch comprises a rotor that is movable in a substantially arcuate path between the charge position and the discharge position.

5. The cardiac defibrillator as in claim 1, further comprising:

means for moving the movable switch between the charge position and the discharge position.

6. The cardiac defibrillator as in claim 1, further comprising:

means for latching the movable switch in the charge position and means for releasing the movable switch from the charge position.

7. The cardiac defibrillator as in claim 1, wherein the energy source comprises a high-voltage battery.

8. The cardiac defibrillator as in claim 7, wherein the high-voltage battery comprises a plurality of batteries connected in a series relationship.

9. The cardiac defibrillator as in claim 1, wherein the means for delivering the cardiac defibrillation pulse from the cardiac defibrillator to the patient comprises a pair of electrodes attachable to the patient.

10. The cardiac defibrillator as in claim 5, wherein the means for moving the movable switch comprises a spring.

2. A cardiac defibrillator for delivering a cardiac defibrillation pulse to a patient comprising:

an electrical energy source;

an energy storage capacitor for storing an electrical charge from the electrical energy source;

a movable switch capable of moving between a charge position and a discharge position;

a first electrical contact connected to the movable switch such that the first electrical contact moves in a contact path as the movable switch moves between the charge and discharge positions, the first electrical contact being electrically coupled to the energy storage capacitor;

a second electrical contact disposed within the contact path and connectable to means for delivering the cardiac defibrillation pulse to the patient, wherein the cardiac defibrillation pulse is delivered to the patient when the first and second electrical contacts are engaged, the duration of the cardiac defibrillation pulse being variable by changing the length of the second electrical contact that is disposed in the contact path thereby varying the length of time that the first and second electrical contacts are engaged; and

a third electrical contact disposed in the contact path, wherein the third electrical contact is connected to a discharge resistor that removes charge from the energy storage capacitor when the movable switch is in the discharge position.

11. A cardiac defibrillator for applying a defibrillation pulse to a patient, comprising:

a battery;

an energy storage capacitor for storing a charge from the battery;

electrodes connectable to the patient for delivering the defibrillation pulse from the cardiac defibrillator to the patient;

a switch rotor capable of rotating in a substantially arcuate path between a charge position and a discharge position, the switch rotor further comprising a rotor contact that is electrically coupled to the energy storage capacitor, wherein the rotor contact rotates in a rotor contact path as the switch rotor rotates between the charge and discharge positions;

a battery contact disposed within the rotor contact path such that the battery contact is connected to the switch rotor contact thereby connecting the battery to the energy storage capacitor when the switch rotor is in the charge position; and

an electrode contact disposed within the rotor contact path and coupled to the electrodes, the electrode contact selected from a plurality of contacts, each having a different contact length, wherein the defibrillation pulse is delivered to the patient when the rotor contact engages the electrode contact, the duration of the defibrillation pulse being variable by changing the length of the electrode contact that lies in the rotor contact path thereby varying the time that the electrode contact and the rotor contact are engaged as the switch rotor rotates between the charge and discharge positions.

13. The cardiac defibrillator as in claim 11, further comprising:

means for moving the switch rotor from the charge position to the discharge position.

14. The cardiac defibrillator as in claim 11, further comprising:

means for latching the switch rotor in the charge position and means for releasing the switch rotor from the charge position.

15. The cardiac defibrillator as in claim 11, wherein the battery comprises a plurality of disc type batteries stacked in a series relationship.

12. A cardiac defibrillator for applying a defibrillation pulse to a patient, comprising:

a battery;

an energy storage capacitor for storing a charge from the battery;

electrodes connectable to the patient for delivering the defibrillation pulse from the cardiac defibrillator to the patient;

a switch rotor capable of rotating in a substantially arcuate path between a charge position and a discharge position, the switch rotor further comprising a rotor contact that is electrically coupled to the energy storage capacitor, wherein the rotor contact rotates in a rotor contact path as the switch rotor rotates between the charge and discharge positions;

a battery contact disposed within the rotor contact path such that the battery contact is connected to the switch rotor contact thereby connecting the battery to the energy storage capacitor when the switch rotor is in the charge position;

an electrode contact disposed within the rotor contact path and coupled to the electrodes, wherein the defibrillation pulse is delivered to the patient when the rotor contact engages the electrode contact, the duration of the defibrillation pulse being variable by changing the length of the electrode contact that lies in the rotor contact path thereby varying the time that the electrode contact and the rotor contact are engaged as the switch rotor rotates between the charge and discharge positions; and

a discharge contact disposed within the rotor contact path and connected to a discharge resistor, wherein the discharge contact is connected to the rotor contact when the switch rotor is in the discharge position thereby allowing the discharge resistor to dissipate charge from the energy storage capacitor.

16. Apparatus for delivering a cardiac defibrillation pulse to a patient'"'"'s heart muscle comprising:

an electrical energy source;

a switch contact;

means for the moving the switch contact along a switch contact path between a charge position and a discharge position;

an electrode contact disposed in the switch contact path, wherein the cardiac defibrillation pulse is delivered to the patient'"'"'s heart muscle when the switch contact engages the electrode contact, the duration of the cardiac defibrillation pulse being variable by varying the length of time the switch contact and the electrode contact are engaged; and

energy storage means for storing an electrical charge from the electrical energy source, wherein the energy storage means is electrically coupled to the switch contact.

17. The apparatus as in claim 16, further comprising:

a battery contact connected to the electrical energy source and disposed in the switch contact path such that the switch contact engages the battery contact when the switch contact is in the charge position.

18. Apparatus for delivering a cardiac defibrillation pulse to a patient'"'"'s heat muscle comprising:

an electrical energy source;

a switch contact;

means for moving the switch contact along a switch contact path between a charge position and a discharge position;

an electrode contact disposed in the switch contact path, wherein the cardiac defibrillation pulse is delivered to the patient'"'"'s heart muscle when the switch contact engages the electrode contact, the duration of the cardiac defibrillation pulse being variable by varying the length of time the switch contact and the electrode contact are engaged;

energy storage means for storing an electrical charge from the electrical energy source;

means for dissipating charge from the energy storage means; and

a discharge contact connected to the means for dissipating charge from the energy storage means, wherein the discharge contact is disposed in the switch contact path such that charge is dissipated from the energy storage means when the switch contact is in the discharge position.

19. The apparatus as in claim 18, wherein the means for dissipating charge from the energy storage means comprises a resistor.

20. The apparatus as in claim 18, wherein the means for moving the switch contact between the charge position and the discharge position comprises a spring.

21. Apparatus for delivering a biphasic cardiac defibrillation pulse to a patient comprising:

an electrical energy source;

energy storage means for storing an electrical charge from the electrical energy source;

a switch contact capable of moving along a switch contact path;

means for moving the switch contact along the switch contact path;

a first electrode contact connectable to means for delivering the cardiac defibrillation pulse to the patient and disposed in the switch contact path such that a first cardiac defibrillation pulse having a first polarity is delivered to the patient as the switch contact engages the first electrode contact, the duration of the first cardiac defibrillation pulse being variable by changing the length of the first electrode contact that lies in the switch contact path;

a second electrode contact connectable to means for delivering the cardiac defibrillation pulse to the patient and disposed in the switch contact path such that a second cardiac defibrillation pulse having a second polarity is delivered to the patient as the switch contact engages the second electrode contact, the duration of the second cardiac defibrillation pulse being variable by changing the length of the second electrode contact that lies in the switch contact path; and

a discharge contact disposed in the switch contact path, wherein the discharge contact is connected to means for dissipating charge from the energy storage means when the switch contact engages the discharge contact.

22. The apparatus as in claim 21, wherein the switch contact moves between a charge position and a discharge position along the switch contact path.

23. The apparatus as in claim 21, further comprising:

a battery contact connected to the electrical energy source and disposed in the switch contact path such that the energy storage means is connected to the electrical energy source when the switch contact is in the charge position.