Filtering patient signal also for ventilation artifacts
View Patent ↗In embodiments, an external medical device is intended to care for a patient. If it receives an input that signifies that ventilation artifact is present in a signal of the patient, it transmits a corrective signal responsive to the received input. In further embodiments, a patient signal is received, which is generated from a patient while the patient is or was receiving chest compressions at a frequency Fc, and also receiving ventilations at frequency Fv. At least one filter mechanism may be applied to the patient signal to substantially remove artifacts at a) frequency Fc, b) a higher harmonic of frequency Fc, and c) a third frequency substantially equaling frequency Fc plus or minus frequency Fv, while substantially passing other frequencies between them. As a result, the patient signal can be cleaner, for diagnosing the patient's state more accurately.
1. An external device, comprising:
a housing; and
a processor within the housing configured to:
receive a patient signal generated from a patient while the patient is receiving chest compressions at a frequency Fc from a mechanical chest compression device, and while the patient is also receiving ventilations at a frequency Fv from a ventilator, and
cause to be applied at least one filter mechanism to the patient signal to substantially remove from the patient signal artifacts at the frequency Fc, at a first harmonic of the frequency Fc, and at a third frequency substantially equaling the frequency Fc plus the frequency Fv, the third frequency having a value between the frequency Fc and the first harmonic of the frequency Fc, while substantially passing the patient signal at other frequencies between the frequency Fc and the third frequency and between the third frequency and the first harmonic.
2. The device of claim 1 , in which
the patient signal is an ECG signal.
3. The device of claim 1 , in which
the patient signal is an impedance signal.
4. The device of claim 1 , further comprising:
an energy storage module within the housing for storing an electrical charge, and
a defibrillation port for guiding via electrodes the stored electrical charge to the patient.
5. The device of claim 1 , in which
a value of the frequency Fc is input in the device.
6. The device of claim 5 , in which
the frequency Fc is input by being looked up from an inputted identification of the mechanical chest compression device.
7. The device of claim 5 , in which
the frequency Fc is input by detecting and analyzing the chest compressions.
8. The device of claim 1 , in which
a value of the frequency Fv is input in the device.
9. The device of claim 8 , in which
the frequency Fv is input by being looked up from an inputted identification of the ventilator.
10. The device of claim 8 , in which
the frequency Fv is input by detecting and analyzing the ventilations.
11. The device of claim 1 , in which
the processor is configured to apply the filter mechanism responsive to an input by a user.
12. The device of claim 1 , in which
the filter mechanism further substantially rejects artifacts at two more frequencies that are additional higher harmonics of the frequency Fc.
13. The device of claim 1 , further comprising:
a display in connection with the housing, and
in which the processor is further configured to cause the display to present visually to a user a version of the patient signal with the artifacts substantially removed.
14. The device of claim 1 , further comprising:
a memory, and
in which the processor is further configured to store in the memory a version of the patient signal with the artifacts substantially removed.
15. The device of claim 1 , in which
the filter mechanism comprises a comb filter.
16. The device of claim 15 , in which
the filter mechanism has a Q value of no less than 4.
17. The device of claim 1 , in which
the filter mechanism comprises a plurality of notch filters.
18. The device of claim 17 , in which
the filter mechanism has a Q value of no less than 4.
19. The device of claim 17 , in which
the plurality of notch filters has a 3 dB notch width of no more than 0.5 Hz.
20. The device of claim 1 , in which
the filter mechanism includes a non-adaptive filter.
21. The device of claim 1 , in which
the processor is further configured to monitor an impedance signal of the patient, and to further detect return of spontaneous circulation by applying a signal-averaging filter to the impedance signal.
22. The device of claim 1 , in which
the patient signal is an impedance signal, and
the processor is further configured to detect return of spontaneous circulation by applying a signal-averaging filter to the impedance signal.
23. A non-transitory computer-readable storage medium storing one or more programs which, when executed by at least one device, they result in:
receiving a patient signal generated from a patient while the patient is or was receiving chest compressions at a frequency Fc from a mechanical chest compression device, and while the patient is also receiving ventilations at a frequency Fv from a ventilator; and
applying at least one filter mechanism to the patient signal to substantially remove from the patient signal artifacts at the frequency Fc, at a first harmonic of the frequency Fc, and at a third frequency substantially equaling the frequency Fc plus the frequency Fv, the third frequency having a value between the frequency Fc and the first harmonic of the frequency Fc, while substantially passing the patient signal at other frequencies between the frequency Fc and the third frequency and between the third frequency and the first harmonic.
24. A method comprising:
receiving a patient signal generated from a patient while the patient is receiving chest compressions at a frequency Fc from a mechanical chest compression device, and while the patient is also receiving ventilations at a frequency Fv from a ventilator; and
applying at least one filter mechanism to the patient signal to substantially remove from the patient signal artifacts at the frequency Fc, at a first harmonic of the frequency Fc, and at a third frequency substantially equaling the frequency Fc plus the frequency Fv, the third frequency having a value between the frequency Fc and the first harmonic of the frequency Fc, while substantially passing the patient signal at other frequencies between the frequency Fc and the third frequency and between the third frequency and the first harmonic.
25. The device of claim 1 , in which
the filter mechanism further substantially removes from the patient signal artifacts at the frequency Fv.
26. The device of claim 1 , in which
the filter mechanism further substantially removes from the patient signal artifacts at the frequency 2Fv.