Wearable cardioverter defibrillator (WCD) system warning ambulatory patient by weak alerting shock
In embodiments, a wearable cardioverter defibrillator (WCD) system is configured to be worn by an ambulatory patient. In the event that the WCD system determines that defibrillation is needed, it delivers a defibrillation shock. To diminish the possibility that the patient will be shocked due to a false positive detection, the WCD system alerts a patient that a defibrillation shock is imminent, and invites them to react to avert it. Alerting may be by a very weak shock, or jolt. Alerting by a jolt can be a last resort warning. An advantage can be that the patient has a higher chance of being alerted by the jolt, especially in the event that the patient is not reacting to other human-perceptible alerts, such as when the patient is riding a motorcycle.
1. A wearable cardioverter defibrillator (WCD) system, comprising:
an energy storage module configured to store an electrical charge via a defibrillation electrode;
a support structure configured to be worn by an ambulatory patient to maintain the defibrillation electrode on a skin of the ambulatory patient external to a body of the ambulatory patient;
a sensor configured to sense a parameter of the ambulatory patient via an Electrocardiogram (ECG) electrode separate from the defibrillation electrode and to render an input responsive to the sensed parameter; and
a processor configured to:
determine from the input whether a defibrillation shock condition is met,
provide a first level of warning to the patient, responsive to the defibrillation shock condition being met, about an impending defibrillation shock,
escalate to a second level of warning to the patient when a jolt override condition is not met by causing at least some of the stored electrical charge to be discharged via the defibrillation electrode through the ambulatory patient to deliver to the skin of the ambulatory patient an alerting shock, when enabled, having an energy between 0.001 joules (J) and 20 J, wherein the processor can be configured, prior to the defibrillation shock condition being met, to enable or disable operation of the alerting shock;
cause, responsive to the defibrillation shock condition being met and after delivery of the alerting shock, at least some of the stored electrical charge to be discharged via the defibrillation electrode through the ambulatory patient to deliver to the ambulatory patient a defibrillation shock having an energy of at least 50 J; and
prevent delivery of the defibrillation shock when a cancel input is received after delivery of the alerting shock and before delivery of the defibrillation shock.
2. The WCD system of claim 1 , in which
the parameter includes an Electrocardiogram (ECG) signal of the patient; and
the WCD system further comprises a sound detector to detect an ambient sound level, wherein the processor is further configured to deliver the alerting shock when the ambient sound level is greater than a threshold noise level, and to otherwise not deliver the alerting shock.
3. The WCD system of claim 1 , further comprising:
a user interface, and in which
the processor is further configured to:
cause the user interface to emit a warning human-perceptible indication as the first level of waring to the patient, and
the alerting shock and the defibrillation shock are not delivered responsive to a first patient cancel condition being met within a first waiting time after the warning human-perceptible indication is emitted.
4. The WCD system of claim 3 , in which
the first patient cancel condition is met responsive to a cancel input being received by the user interface within the first waiting time.
5. The WCD system of claim 3 , in which
the defibrillation shock is not delivered responsive to a second patient cancel condition being met within a second waiting time after the alerting shock is thus delivered.
6. The WCD system of claim 5 , further comprising:
a user interface, and in which
the second patient cancel condition is met responsive to a cancel input being received by the user interface within the second waiting time.
7. The WCD system of claim 1 , further comprising:
a fluid reservoir configured to store a fluid; and
a fluid deploying mechanism, and in which
the processor is further configured to cause the fluid deploying mechanism to deploy the stored fluid prior to causing the alerting shock to be delivered.
8. The WCD system of claim 1 , in which
the alerting shock is not delivered to the patient responsive to the jolt override condition being met.
9. The WCD system of claim 8 , in which
the sensor includes a motion detector configured to output a motion detection signal indicative of an amount of motion sensed by the motion detector, and
the jolt override condition is determined to exist responsive to the output motion detection signal indicating an amount of motion less than a threshold.
10. The WCD system of claim 8 , further comprising:
a user interface, and in which
the user interface includes a sound detector configured to output a sound detection signal indicative of a sound level sensed by the sound detector, and
the jolt override condition is determined to exist responsive to the output sound detection signal indicating a sound level less than a threshold.
11. The WCD system of claim 1 , in which
the processor is further configured to:
cause at least some of the stored electrical charge to be discharged through the ambulatory patient to deliver to the ambulatory patient another alerting shock having an energy less than 20 J.
12. The WCD system of claim 1 , wherein the energy of the alerting shock is less than 0.1 joule.
13. The WCD system of claim 1 , wherein the energy of the alerting shock is one percent or less of the energy of the defibrillation shock.
14. The WCD system of claim 1 , further comprising a user interface coupled with the processor, wherein operation of the alerting shock can be enabled or disabled via the user interface based at least in part on an activity to be engaged in by the ambulatory patient.
15. A non-transitory computer-readable storage medium storing one or more programs which, when executed by at least one processor of a wearable cardioverter defibrillator (WCD) system, the WCD system including an energy storage module storing an electrical charge, a defibrillation electrode, a support structure worn by an ambulatory patient to maintain the defibrillation electrode on a skin of the ambulatory patient external to a body of the ambulatory patient, and a sensor sensing a parameter of the ambulatory patient via an Electrocardiogram (ECG) electrode separate from the defibrillation electrode and rendering an input responsive to the sensed parameter, these one or more programs result in operations comprising:
enabling or disabling operation of the alerting shock prior to a defibrillation shock condition being met;
determining from the input whether the defibrillation shock condition is met;
providing a first level of warning to the patient, responsive to the defibrillation shock condition being met, about an impending defibrillation shock,
escalating to a second level of warning to the patient when a jolt override condition is not met by causing at least some of the stored electrical charge to be discharged via the defibrillation electrode through the ambulatory patient to deliver to the skin of the ambulatory patient an alerting shock, when enabled, having an energy between 0.001 joules (J) and 20 J;
causing, responsive to the defibrillation shock condition being met and after delivery of the alerting shock, at least some of the stored electrical charge to be discharged via the defibrillation electrode through the ambulatory patient to deliver to the ambulatory patient a defibrillation shock having an energy of at least 50 J; and
preventing delivery of the defibrillation shock when a cancel input is received after delivery of the alerting shock and before delivery of the defibrillation shock.
16. The non-transitory computer-readable storage medium of claim 15 , wherein the energy of the alerting shock is less than 0.1 joule.
17. The non-transitory computer-readable storage medium of claim 15 , wherein the energy of the alerting shock is one percent or less of the energy of the defibrillation shock.
18. A method for a wearable cardioverter defibrillator (WCD) system, the WCD system including an energy storage module storing an electrical charge, a defibrillation electrode, a support structure worn by an ambulatory patient to maintain the defibrillation electrode on a skin of the ambulatory patient external to a body of the ambulatory patient, a sensor sensing a parameter of the ambulatory patient via an Electrocardiogram (ECG) electrode separate from the defibrillation electrode, and a processor, the method comprising:
enabling or disabling operation of the alerting shock prior to a defibrillation shock condition being met;
rendering, by the sensor, an input responsive to the sensed parameter of the ambulatory patient;
determining from the input whether the defibrillation shock condition is met;
providing a first level of warning to the patient, responsive to the defibrillation shock condition being met, about an impending defibrillation shock,
escalating to a second level of warning to the patient when a jolt override condition is not met by causing at least some of the stored electrical charge to be discharged via the defibrillation electrode through the ambulatory patient to deliver to the skin of the ambulatory patient an alerting shock, when enabled, having an energy between 0.001 joules (J) and 20 J;
causing, responsive to the defibrillation shock condition being met and after delivery of the alerting shock, at least some of the stored electrical charge to be discharged via the defibrillation electrode through the ambulatory patient to deliver to the ambulatory patient a defibrillation shock having an energy of at least 50 J; and
preventing delivery of the defibrillation shock when a cancel input is received after delivery of the alerting shock and before delivery of the defibrillation shock.
19. The method of claim 18 , in which
the parameter includes an Electrocardiogram (ECG) signal of the patient; and
further comprising delivering the alerting shock when an ambient sound level detected by a sound detector of the WCD system is greater than a threshold noise level, and otherwise not delivering the alerting shock.
20. The method of claim 18 , in which
the WCD system further includes a user interface, and
the alerting shock is not delivered responsive to a disable input being received by the user interface.
21. The method of claim 18 , in which
the WCD system further includes a user interface, and
further comprising:
causing the user interface to emit a warning human-perceptible indication as the first level of waring to the patient, and
in which the alerting shock and the defibrillation shock are not delivered responsive to a first patient cancel condition being met within a first waiting time after the warning human-perceptible indication is thus emitted.
22. The method of claim 21 , in which
the first patient cancel condition is met responsive to a cancel input being received by the user interface within the first waiting time.
23. The method of claim 21 , in which
the defibrillation shock is not delivered responsive to a second patient cancel condition being met within a second waiting time after the alerting shock is thus delivered.
24. The method of claim 23 , in which
the WCD system further includes a user interface, and
the second patient cancel condition is met responsive to a cancel input being received by the user interface within the second waiting time.
25. The method of claim 18 , in which
the WCD system further includes a fluid reservoir storing a fluid and a fluid deploying mechanism, and
further comprising:
causing the fluid deploying mechanism to deploy the stored fluid prior to causing the alerting shock to be delivered.
26. The method of claim 18 , wherein the alerting shock is not delivered to the patient responsive to the jolt override condition being met.
27. The method of claim 26 , in which
the sensor includes a motion detector outputting a motion detection signal indicative of an amount of motion sensed by the motion detector, and
the jolt override condition is determined to exist responsive to the output motion detection signal indicating an amount of motion less than a threshold.
28. The method of claim 26 , in which
the WCD system further includes a user interface,
the user interface includes a sound detector outputting a sound detection signal indicative of a sound level sensed by the sound detector, and
the jolt override condition is determined to exist responsive to the output sound detection signal indicating a sound level less than a threshold.
29. The method of claim 18 , further comprising
causing at least some of the stored electrical charge to be discharged through the ambulatory patient to deliver to the ambulatory patient another alerting shock having an energy less than 20 J.
30. The method of claim 18 , wherein the energy of the alerting shock is less than 0.1 joule.
31. The method of claim 18 , wherein the energy of the alerting shock is one percent or less of the energy of the defibrillation shock.