Medium voltage therapy applications in treating cardiac arrest

• US 20060142809A1
• Filed: 11/22/2005
• Published: 06/29/2006
• Est. Priority Date: 11/24/2004
• Status: Active Grant

• Current Assignee: Galvani, Ltd.
• Original Assignee: Galvani, Ltd.
• Inventors: Kroll, Mark, Kroll, Kai, Bugliosi, Tom
• Granted Patent: US 8,401,637 B2
• Time in Patent Office: Days
• US Class Current: 607/5
• CPC Class Codes: A61N 1/3625 External stimulators
• CPC Class Codes: A61N 1/39044 in combination with cardiopulmonary resuscitation [CPR] therapy
• CPC Class Codes: A61N 1/39046 User protection from shock
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting
• CPC Class Codes: A61N 1/3993 User interfaces for automatic external defibrillators

Abstract

A method and system for treating an individual experiencing cardiac arrest using an automatic external defibrillator (AED) includes placing a first and a second electrode of the AED in electrical communication with an exterior surface of the individual. A need to apply a high voltage defibrillation signal to the individual is automatically determined. The method also includes automatically causing the AED to apply a medium voltage therapy (MVT) signal through the first and the second electrodes to the individual. The MVT signal is applied to induce a hemodynamic effect in the individual. Alternatively, or additionally, the MVT signal is applied to induce a respiratory effect in the individual. Optionally, the MVT signal is applied before determining the need to apply the defibrillation signal.

Claims

1. An improved automated external defibrillator (AED), the AED including a plurality of electrodes that interface with an exterior surface of a patient, defibrillation circuitry that generates and delivers a defibrillation shock to the patient via the electrodes, patient monitoring circuitry that senses cardiac activity of the patient, and a controller interfaced with the patient monitoring circuitry and the defibrillation circuitry that controls generation and delivery of the defibrillation shock in response to a patient condition that is treatable by the defibrillation shock, the improvement comprising:

logic in the controller that recognizes a patient condition that is treatable by cardiopulmonary resuscitation (CPR); and

electrical CPR circuitry interfaced with the controller to generate and deliver medium voltage therapy (MVT) via the electrodes in response to the patient condition that is treatable by CPR, the MVT producing both a hemodynamic effect and a respiratory effect in the patient.

2. The improved AED of claim 1, wherein the electrical CPR circuitry generates MVT that includes a first energy burst and a second energy burst.

3. The improved AED of claim 2, wherein the first energy burst is adapted to cause sympathetic nerve stimulation facilitating cardiac myocyte contractility and excitability in the patient.

4. The improved AED of claim 2, wherein the first energy burst includes a first series of pulses grouped into a first packet, and the second energy burst includes a second series of pulses grouped into a second packet.

5. The improved AED of claim 4, wherein the logic in the controller selectively adjusts at least one MVT control parameter controlling the generating and delivery of the MVT that affects at least one characteristic of the MVT selected from the group consisting of:

a time duration between successive pulses, a pulse duration, a time duration between the first packet and the second packet, or any combination thereof.

6. The improved AED of claim 1, wherein the MVT includes at least one pulse having a time constant that is long enough to stimulate cardiac tissue.

7. The improved AED of claim 1, wherein the MVT includes at least one pulse having a time constant that is short enough to stimulate skeletal muscle tissue in the patient.

8. The improved AED of claim 1, wherein the improvement further comprises:

monitoring equipment operably interfaced with the controller to automatically monitor an additional physiologic condition of the patient.

9. The improved AED of claim 8, wherein the monitoring equipment facilitates at least one type of automatic monitoring selected from the group consisting of:

monitoring of a patient'"'"'s fingertip pulse oximetry, monitoring of a patient'"'"'s respiration, and monitoring of an arterial pulse of the patient.

10. The improved AED of claim 1, wherein the MVT causes at least one physiologic effect in the patient selected from the group consisting of:

coronary perfusion, a plurality of muscular contraction events in the patient'"'"'s chest region, a plurality of muscular contraction events in the patient'"'"'s abdominal region, respiratory ventilation, and stimulation of the patient'"'"'s phrenic nerve.

11. The improved AED of claim 1, wherein the AED further includes an operator interface that includes a graphical display interfaced with the controller and wherein the improvement further comprises:

a display on the graphical display that includes a plot of an electrocardiogram (ECG) curve obtained from the patient, and an MVT application indicator plotted together with the ECG curve, the MVT indicator indicating at least one instance of MVT application relative in time to events represented by the ECG curve.

12. A method of operating a cardiac electrotherapy system that is external to a subject, wherein the system includes a first and a second electrode, a monitor sub-system, an energy delivery sub-system, and a controller, the method comprising:

placing the first and the second electrode on an exterior surface of the subject to complete a circuit that includes the energy delivery sub-system, the first and the second electrode, and the subject;

activating, via the controller, the monitor sub-system such that the monitor sub-system senses cardiac activity of the subject;

selectively activating, via the controller in response to the monitor sub-system, the energy delivery sub-system to apply a first energy signal to the subject through the first and the second electrode, wherein the first energy signal;

has a magnitude that is incapable of causing a defibrillation effect in a subject that is human;

includes a short time constant component capable of stimulating skeletal muscle in a subject that is human; and

includes a long time constant component capable of stimulating cardiac tissue in a subject that is human.

13. The method of claim 12, further comprising:

selectively activating, via the controller in response to the monitor sub-system, the energy delivery sub-system to apply a second energy signal to the subject, wherein the second energy signal has a magnitude that is capable of causing a defibrillation effect in a subject that is human.

14. The method of claim 13, wherein the activating of the energy delivery sub-system to apply the first energy signal is performed before an assessing by the controller of the suitability of applying the second energy signal to the subject.

15. The method of claim 12, wherein the short time constant component has a waveform that is capable of causing a respiratory effect in a subject that is human.

16. The method of claim 12, wherein the long time constant component has a waveform that is capable of causing a hemodynamic effect in a subject that is human.

17. The method of claim 12, wherein the activating of the monitor sub-system includes detecting cardiac activity that represents an absence of normal cardiac activity of a subject that is human based on at least one physiologic condition selected from the group consisting of:

an absence of a pulse, and an absence of a normal cardiac rhythm.

18. The method of claim 12, wherein the first energy signal has an amplitude and waveform adapted to cause at least one physiologic effect in a subject that is human, the at least one physiologic effect selected from the group consisting of:

a plurality of muscular contraction events in a chest region, a plurality of muscular contraction events in an abdominal region, respiratory ventilation, phrenic nerve stimulation, sympathetic nerve stimulation facilitating cardiac myocyte contractility and excitability, and coronary perfusion.

19. The method of claim 12, further comprising:

automatically conducting an effectiveness assessment of the first energy signal; and

selectively adjusting, via the controller and the energy delivery sub-system, at least one variable parameter of the first signal to effect at least one corresponding in a measured value of the effectiveness assessment.

20. The method of claim 12, wherein the first energy signal includes a first energy burst defined by a first series of pulses grouped into a first packet, and a second energy burst defined by a second series of pulses grouped into a second packet, and further comprising:

selectively adjusting, via the controller and the energy delivery sub-system, at least one signal control parameter that affects at least one waveform characteristic of the first energy burst selected from the group consisting of;

a time duration between successive intra-packet pulses, a pulse width of each of the pulses of the first series, and a time duration between the first and the second packets.

21. An automated external defibrillator (AED) system comprising:

a plurality of electrodes that interface with an exterior surface of a patient;

defibrillation circuitry that generates and delivers a defibrillation shock to the patient via the electrodes in response to a patient condition that is treatable by defibrillation;

electrical CPR circuitry that generates and delivers medium voltage therapy (MVT) via the electrodes in response to a patient condition that is treatable by CPR;

patient monitoring sub-system that senses cardiac activity of the patient;

a controller interfaced with the patient monitoring sub-system, the defibrillation circuitry and the electrical CPR circuitry that controls generation and delivery of the defibrillation shock in response to the patient condition that is treatable by defibrillation and controls generation and delivery of the MVT in response to the patient condition that is treatable by CPR such that the MVT is delivered as a pulsed output having a pulsed output voltage of between 20-1000 V, a pulsed output current of between 0.05-10.00 A, a pulsed packet rate of between 20-180 packets/minute, a pulsed packet duration of between 10-3000 ms, an intra-packet pulse duration of between 0.05-10.0 ms, and an intra-packet pulse rate of between 20-500 Hz.

22. The AED system of claim 21 wherein the MVT is optimized for generating a coronary perfused pulse and the pulsed output has a pulsed output voltage of between 75-300 V, a pulsed output current of between 0.5-6.0 A, a pulsed packet rate of between 70-100 packets/minute, a pulsed packet duration of between 80-120 ms, an intra-packet pulse duration of between 2.0-6.0 ms, and an intra-packet pulse rate of between 30-75 Hz.

23. The AED system of claim 21 wherein the pulsed output of the MVT is delivered multiple times by the controller with varied parameter values and an initial parameter value of the pulsed output has a pulsed output voltage of about 250 V, a pulsed output current of between 1.0-5.0 A, a pulsed packet rate of about 90 packets/minute, a pulsed packet duration of between 100 ms, an intra-packet pulse duration of about 4.0 ms, and an intra-packet pulse rate of about 100 Hz.

24. The AED system of claim 21 wherein the MVT is optimized for generating a respiration and the pulsed output has a pulsed output voltage of between 75-300 V, a pulsed output current of between 50-500 mA, a pulsed packet rate of between 10-30 packets/minute, a pulsed packet duration of between 0.5-3.0 second, an intra-packet pulse duration of between 0.05 and 0.2 ms, and an intra-packet pulse rate of between 25-150 Hz.

25. The AED system of claim 21 wherein the patient monitoring sub-system further includes at least one component to monitor a measured effectiveness of the MVT and wherein the controller selectively adjusts at least one variable parameter of the pulsed output in response to the measured effectiveness.

26. The AED system of claim 25, wherein the at least one variable parameter of the pulsed output is selected from the group consisting of:

the pulsed output voltage, the pulsed packet rate, the pulsed packet duration, the intra-packet pulse duration, and the intra-packet pulse rate.