ALERTING USERS OF CPR FEEDBACK DEVICE OF DETECTED MAGNETIC INTERFERENCE

• US 20130225972A1
• Filed: 08/29/2012
• Published: 08/29/2013
• Est. Priority Date: 09/30/2010
• Status: Active Grant

• Current Assignee: Physio-Control Incorporated (Stryker Corporation)
• Original Assignee: Physio-Control Incorporated (Stryker Corporation)
• Inventors: Banville, Isabelle L., Marx, Robert Peter Jr., Brown, David Thomas, Nova, Richard C.
• Granted Patent: US 10,098,573 B2
• Time in Patent Office: Days
• US Class Current: 600/409
• CPC Class Codes: A61B 5/1126 using a particular sensing technique
• CPC Class Codes: A61H 2201/5061 Force sensors
• CPC Class Codes: A61H 2201/5064 Position sensors
• CPC Class Codes: A61H 2201/5071 Pressure sensors
• CPC Class Codes: A61H 2201/5084 Acceleration sensors
• CPC Class Codes: A61H 2201/5097 wireless
• CPC Class Codes: A61H 31/005 with feedback for the user
• CPC Class Codes: A61H 31/007 Manual driven

Abstract

A medical device and/or a method are used by a rescuer who is caring for a patient. The depth of CPR chest compressions is determined, by detecting magnetic fields. An interference is sensed, which is not associated with the CPR chest compressions, but which is superimposed on the detected magnetic fields. Appropriate countermeasures may be taken, if the sensed interference is larger than a threshold.

Claims

1. A medical device for communicating to a user about CPR chest compressions performed on a patient, the medical device comprising:

a detector that is suitable for detecting magnetic fields associated with the CPR chest compressions;

a processor for estimating depths of the CPR chest compressions from the detected magnetic fields;

an interface for communicating the estimated depths to the user;

a sensing functionality for sensing whether, in a vicinity of the detector, there is interference superimposed on the detected magnetic fields, which interference is not associated with the CPR chest compressions;

a comparator for determining whether an amount of the sensed interference is above a threshold; and

a control switch having a normal position and an alert position, the control switch being thrown from the normal position to the alert position if it is determined that the amount of the sensed interference is above the threshold.

2. The device of claim 1, in which

the sensed interference is static.

3. The device of claim 1, in which

the sensed interference is dynamic.

4. The device of claim 1, in which

the sensed interference is due to the presence of a conductor in the vicinity of the device.

5. The device of claim 1, in which

at least a first coil and a second coil are included, and

sensing is performed by energizing the first and the second coils, and measuring and comparing current signals induced in the second and first coils respectively by the energizing.

6. The device of claim 1, in which

at least two transmit coils and two receive coils distinct from the transmit coils are included, and

sensing is performed by energizing the two transmit coils, and comparing current signals induced in the two receive coils by the energizing.

7. The device of claim 1, in which

sensing is performed by energizing a coil of the device, and monitoring how an impedance of the coil changes in response to the energizing.

8. The device of claim 1, in which

at least at least one transmit coil and one receive coil are included, and

sensing is performed by energizing the transmit coil with a transmit signal so as to induce a receive signal in the receive coil, and detecting a phase delay of the receive signal relative to the transmit signal.

9. The device of claim 1, in which

a hardware phase discriminator is included.

10. The device of claim 1, in which

the estimated depths are adjusted for the sensed interference if the control switch is thrown from the normal position to the alert position.

11. The device of claim 1, in which

a human-perceptible warning is issued to the user if the control switch is thrown from the normal position to the alert position.

12. The device of claim 11, in which

the human-perceptible warning is issued via the interface.

13. The device of claim 1, in which

the detector is disabled if the control switch is thrown from the normal position to the alert position.

14. The device of claim 1, in which

the communicating by the interface is disabled if the control switch is thrown from the normal position to the alert position.

15. A method for a medical device having a detector that is suitable for detecting magnetic fields associated with the CPR chest compressions, a processor for estimating depths of the CPR chest compressions from the detected magnetic fields and a control switch having a normal position and an alert position, the method comprising:

sensing whether, in a vicinity of the detector, there is interference superimposed on the detected magnetic fields, which interference is not associated with the CPR chest compressions;

determining whether an amount of the sensed interference is above a threshold; and

if so, throwing the control switch from the normal position to the alert position.

16. The method of claim 15, in which

the sensing takes place substantially continuously as the detector detects magnetic fields associated with successive ones of the CPR chest compressions.

17. The method of claim 15, further comprising:

repeating the sensing.

18. The method of claim 15, in which

the estimated depths are adjusted for the sensed interference if the control switch is thrown from the normal position to the alert position.

19. The method of claim 15, in which

a human-perceptible warning is issued to the user if the control switch is thrown from the normal position to the alert position.

20. The method of claim 15,

in which the medical device further has an interface for communicating the estimated depths to a user,

and further comprising:

issuing a human-perceptible to the user warning via the interface if the control switch is thrown from the normal position to the alert position.

21. The method of claim 15, in which

the detector is disabled if the control switch is thrown from the normal position to the alert position.

22. The method of claim 15,

in which the medical device further has an interface for communicating the measured depth to a user,

and further comprising:

disabling the communicating by the interface if the control switch is thrown from the normal position to the alert position.