Wearable cardioverter defibrillator having adjustable alarm time

Patent metadata

Field	Value
Publication number	US-2018185662-A1
Application number	US-201815863551-A
Country	US
Kind code	A1
Filing date	Jan 5, 2018
Priority date	Jan 5, 2017
Publication date	Jul 5, 2018
Grant date	—

Abstract

A wearable cardioverter defibrillator (WCD) having a processor configured to receive a signal indicating a position and/or movement of the ambulatory patient while the ambulatory patient is wearing the support structure receive the ECG signal, determine from an ECG signal whether a shock criterion is met, determine a confirmation time period and/or a response time period based on the position and/or movement of the ambulatory patient, determine from the ECG signal whether the shock criterion is met after the confirmation time period has elapsed, cause the user interface to generate the shock alert signal based on the shock criterion determined after the confirmation time period has elapsed, and control the discharge circuit to discharge the stored electrical charge when a predetermined time period has elapsed after the shock alert signal.

First claim

We claim:

1 . A wearable cardioverter defibrillator (WCD), comprising:
a support structure configured to be worn by an ambulatory patient; an energy storage module configured to store an electrical charge; a discharge circuit coupled to the energy storage module; electrodes configured to render an electrocardiogram (ECG) signal of the patient while the ambulatory patient is wearing the support structure; a user interface configured to output an alarm in response to a shock alert signal; a motion sensor configured to output a signal indicating a position and/or movement of the ambulatory patient while the ambulatory patient is wearing the support structure; and a processor configured to:
receive the signal from the motion sensor,
receive the ECG signal,
determine from the ECG signal whether a shock criterion is met;
determine a confirmation time period based on the position and/or movement of the ambulatory patient,
determine from the ECG signal whether the shock criterion is met after the confirmation time period has elapsed,
cause the user interface to generate the shock alert signal based on the shock criterion determined after the confirmation time period has elapsed, and
control the discharge circuit to discharge the stored electrical charge when a predetermined time period has elapsed after the shock alert signal.

2 . The WCD of claim 1 , wherein the processor is further configured to:
detect a patient fall in response to the signal from the motion sensor indicating a positional change of the patient from an upright position to a sitting or supine position that violates a positional change threshold, and determine the confirmation time period based on the detected patient fall.

3 . The WCD of claim 2 , wherein the positional change threshold includes a positional change time period or a positional change force, and the patient fall is detected in response to the positional change being less than the positional change time period or greater than the positional change force.

4 . The WCD of claim 2 , wherein the processor is further configured to:
detect whether a patient remains motionless based on the signal from the motion sensor after the detected patient fall, and determine the confirmation time period based on whether the patient remains motionless.

5 . The WCD of claim 4 , wherein the confirmation time period is shorter when the patient fall has been detected and the patient has remained motionless after the detected patient fall than when the patient fall has been detected and the patient has not remained motionless after the detected patient fall.

6 . The WCD of claim 1 , wherein the predetermined time period is a response time period and the processor is further configured to determine the response time period based on the detected fall and an amount of movement of the patient after the detected fall, and control the discharge circuit to discharge the stored electrical charge when the response time period has elapsed after the shock alert signal and a user response has not been received.

7 . The WCD of claim 6 , wherein the response time period is shorter when no movement is detected based on the signal from the motion sensor after the detected fall and the response time period is longer when movement is detected based on the signal from the motion sensor after the detected fall.

8 . The WCD of claim 1 , wherein the processor is further configured to detect noise on the ECG signal and determine the confirmation time period based on the detected noise.

9 . The WCD of claim 1 , further comprising a transmitter configured to output an alert to a remote center when the confirmation time period has elapsed and a user input has not been received at the user interface.

10 . The WCD of claim 1 , wherein the motion sensor is an accelerometer.

11 . The WCD of claim 1 , wherein the processor is further configured to determine the confirmation time period by selecting the confirmation time period from a plurality of confirmation time periods based on the position and/or movement of the ambulatory patient

12 . A wearable cardioverter defibrillator (WCD), comprising:
a support structure configured to be worn by an ambulatory patient; an energy storage module configured to store an electrical charge; a discharge circuit coupled to the energy storage module; electrodes configured to render an electrocardiogram (ECG) signal of the patient while the patient is wearing the support structure; a user interface configured to output an alarm in response to a shock alert signal; a motion sensor configured to output a signal indicating a position and/or movement of the ambulatory patient while the patient is wearing the support structure; and a processor configured to:
receive the signal from the motion sensor,
receive the ECG signal,
determine from the ECG signal whether a shock criterion is met;
cause the user interface to generate the shock alert signal based on the shock criterion,
determine a response time period based on the position and/or movement of the ambulatory patient, and
in a first mode, control the discharge circuit to discharge the stored electrical charge after the response time period has elapsed and a user input has not been received at the user interface, and in a second mode not control the discharge circuit to discharge the stored electrical charge after the user input has been received at the user interface prior to the response time elapsing.

13 . The WCD of claim 12 , wherein the processor is further configured to:
detect a sleeping state of the patient based on the signal from the motion sensor indicating the patient is in a lying position for greater than a minimum time period, and determine the response time period based on the sleeping state.

14 . The WCD of claim 13 , wherein the minimum time period is thirty minutes.

15 . The WCD of claim 13 , wherein the sleeping state is maintained when the signal from the motion sensor detects a patient in an upright position for less than three minutes.

16 . The WCD of claim 13 , wherein the minimum time period does not begin until less than five position changes are detected after detecting the patient is in the lying position.

17 . The WCD of claim 13 , wherein the response time period is greater when the sleeping state is detected than when the sleeping state is not detected.

18 . The WCD of claim 13 , wherein the processor is further configured to detect the sleeping state of the patient based on the motion of the patient determined by the signal from the motion sensor.

19 . The WCD of claim 13 , further comprising a light sensor configured to output a signal indicating an ambience, and wherein the processor is further configured to detect the sleeping state of the patient based on the ambience.

20 . The WCD of claim 13 , further comprising a clock to indicate a time of day, wherein the processor is further configured to detect the sleeping state of the patient based on the time of day.

21 . The WCD of claim 13 , further comprising a sound sensor configured to output a signal indicating sleeping sounds of a patient, wherein the processor is further configured to detect the sleeping state of the patient based on the sleeping sounds.

22 . The WCD of claim 13 , further comprising:
a respiratory sensor to output a signal indicating a respiration rate; and a memory configured to store the signal indicating the respiration rate for

Assignees

• West Affum Holdings Corp

Inventors

• Foshee Jr Phillip D
• Finch David P
• Breske Pamela
• Gustavson Laura M
• Sullivan Joseph L
• Kim Jaeho

Classifications

• A61B5/33

  specially adapted for cooperation with other devices · CPC title

• A61N1/3925

  Monitoring; Protecting · CPC title

• A61B5/4836

  Diagnosis combined with treatment in closed-loop systems or methods (A61B5/0036 takes precedence) · CPC title

• A61N1/3993

  User interfaces for automatic external defibrillators · CPC title

• A61N1/3904

  External heart defibrillators [EHD] · CPC title