Method and device responsive to myoelectrical activity for triggering ventilatory support

• US 6,588,423 B1
• Filed: 06/22/2001
• Issued: 07/08/2003
• Est. Priority Date: 02/27/1998
• Status: Expired due to Term

• Current Assignee: Universite De Montreal, L'
• Original Assignee: Universite De Montreal, L'
• Inventors: Sinderby, Christer
• Primary Examiner(s): Dawson, Glenn K.
• Application Number:
  US09/623,061
• Time in Patent Office: 746 Days
• Field of Search: 128/200.24, 128/204.18, 128/204.21, 128/204.23, 128/204.26, 128/205.24, 128/207.14, 128/207.16, 128/207.18, 128/898
• US Class Current: 128/204.23
• CPC Class Codes: A61B 5/392 Detecting gastrointestinal contractions
• CPC Class Codes: A61M 16/00 Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes stimulating the respiratory movement by mechanical, pneumatic or electrical means, iron lungs combined with gas breathing means A61H31/00
• CPC Class Codes: A61M 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 2210/1014 Diaphragm
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/40 Respiratory characteristics
• CPC Class Codes: A61M 2230/60 Muscle strain, i.e. measured on the user

Abstract

A method and device for triggering ventilatory support to assist the patient'"'"'s respiration. Myoelectrical activity of a patient'"'"'s respiratory-related muscle is sensed to detect respiratory effort, and to produce a myoelectrical signal representative of the sensed muscle myoelectrical activity. Respiratory flow and pressure can also be measured to produce respective respiratory pressure and respiratory flow signals. A logic trigger circuit triggers ventilatory support in relation to the myoelectrical signal, respiratory flow signal and/or respiratory pressure signal to assist respiration of the patient. The amplitude of the myolectrical signal is compared to a given threshold, and ventilatory support is triggered when the amplitude of the myoelectrical signal is higher than this threshold. Increment of myoelectrical signal amplitude can also be detected to trigger ventilatory support, while decrement of the myoelectrical signal amplitude can be detected to request non-triggering of the ventilatory support.

Claims

1. A method for triggering ventilatory support from a ventilatory apparatus connected to a patient'"'"'s respiratory system to assist respiration of said patient, comprising:

sensing myoelectrical activity of a respiratory-related muscle of the patient, to thereby detect respiratory effort of said patient;

in response to the sensed muscle myoelectrical activity, calculating a real-time myoelectrical signal representative of a level or change in respiratory effort; and

activating/deactivating ventilatory support in relation to the myoelectrical signal to synchronise, in real-time, activating/deactivating of the ventilatory support to the patient with respiratory effort of said patient, said activating/deactivating of ventilatory support comprising;

comparing an amplitude, integral, derivative or combination thereof related to the myoelectrical signal to a given threshold; and

activating ventilatory support when said amplitude, integral, derivative or combination thereof is higher than said given threshold.

2. A method for triggering ventilatory support as recited in claim 1, further comprising filtering from the myoelectrical signal at least one of the following disturbances:

motion artifacts, ECG, electrical interference, and high frequency noise.

8. A method for triggering ventilatory support as recited in any one of claims 1, 3, 5, or 6, further comprising:

detecting a level of noise in the myoelectrical signal; and

determining whether the respiratory-related muscle of the patient is active in relation to the detected level of noise.

9. A method for triggering ventilatory support as recited in any one of claims 1, 3, 5, or 6, wherein:

sensing myoelectrical activity comprises sensing myoelectrical activity of the respiratory-related muscle on two opposite sides of the center of a depolarizing region of said respiratory-related muscle; and

calculating a real-time myoelectrical signal comprises;

generating two myoelectrical signal components in response to sensing of the myoelectrical activity of the respiratory-related muscle on the two opposite sides of the center;

of the depolarizing region, respectively, said two myoelectrical signal components having reversed polarities;

subtracting the two myoelectrical signal components from each other to produce a subtraction signal;

adding the two myoelectrical signal components to each other to produce an addition signal;

comparing the addition signal to the subtraction signal; and

accepting the subtraction signal as real-time myoelectrical signal in relation to the comparison between the addition signal and the subtraction signal.

10. A method for triggering ventilatory support as recited in claim 9, wherein the subtraction signal, the addition signal, the multiplied addition-signal and the myoelectrical signal comprise RMS signals.

11. A method for triggering ventilatory support as recited in claim 9, wherein:

comparing the addition signal to the subtraction signal comprises multiplying the addition signal by a predetermined constant to produce a multiplied addition signal, and comparing the multiplied addition signal to the subtraction signal; and

accepting the subtraction signal as real-time myoelectrical signal comprises accepting the subtraction signal as real-time myoelectrical signal when the subtraction signal has an amplitude, integral, derivative or combination thereof higher than an amplitude, integral, derivative or combination thereof related to the multiplied addition signal.

12. A method for triggering ventilatory support as in any of claims 1, 3, 5 or 6, further comprising:

measuring respiratory flow of the patient, and producing a respiratory flow signal;

measuring respiratory pressure of the patient, and producing a respiratory pressure signal; and

activating ventilatory support in relation to the myoelectrical signal, respiratory flow signal and/or respiratory pressure signal to assist respiration of the patient in response to respiratory effort of said patient.

3. A method for triggering ventilatory support from a ventilatory apparatus connected to a patient'"'"'s respiratory system to assist respiration of said patient, comprising:

sensing myoelectrical activity of a respiratory-related muscle of the patient, to thereby detect respiratory effort of said patient;

in response to the sensed muscle myoelectrical activity, calculating a real-time myoelectrical signal representative of a level or change in respiratory effort; and

activating/deactivating ventilatory support in relation to the myoelectrical signal to synchronise, in real-time, activating/deactivating of the ventilatory support to the patient with respiratory effort of said patient, wherein activating/deactivating of ventilatory support comprises;

detecting an increment of an amplitude, integral, derivative or combination thereof related to the myoelectrical signal; and

activating ventilatory support in response to detection of said increment.

4. A method for triggering ventilatory support as recited in claim 3, wherein the increment detection comprises:

multiplying a current sample of the myoelectrical signal by a predetermined constant to produce a multiplied sample;

comparing the multiplied sample to a preceding sample;

of the myoelectrical signal; and

detecting said increment when the amplitude, integral, derivative or combination thereof related to the multiplied sample is higher than the amplitude, integral, derivative or combination thereof related to the preceding sample.

5. A method for triggering ventilatory support from a ventilatory apparatus connected to a patient'"'"'s respiratory system to assist respiration of said patient, comprising:

sensing myoelectrical activity of a respiratory-related muscle of the patient, to thereby detect respiratory effort of said patient;

in response to the sensed muscle myoelectrical activity, calculating a real-time myoelectrical signal representative of a level or change in respiratory effort; and

activating/deactivating ventilatory support in relation to the myoelectrical signal to synchronise, in real-time, activating/deactivating of the ventilatory support to the patient with respiratory effort of said patient, wherein activating/deactivating of ventilatory support comprises;

comparing an amplitude, integral, derivative or combination thereof related to the myoelectrical signal to a given threshold; and

deactivating ventilatory support when said amplitude, integral, derivative or combination thereof is lower than said given threshold.

6. A method for triggering ventilatory support from a ventilatory apparatus connected to a patient'"'"'s respiratory system to assist respiration of said patient, comprising:

sensing myoelectrical activity of a respiratory-related muscle of the patient, to thereby detect respiratory effort of said patient;

in response to the sensed muscle myoelectrical activity, calculating a real-time myoelectrical signal representative of a level or change in respiratory effort; and

activating/deactivating ventilatory support in relation to the myoelectrical signal to synchronise, in real-time, activating/deactivating of the ventilatory support to the patient with respiratory effort of said patient, wherein activating/deactivating of ventilatory support comprises;

detecting a decrement of an amplitude, integral, derivative or combination thereof related to the myoelectrical signal; and

deactivating ventilatory support in response to detection of said decrement.

7. A method for triggering ventilatory support as recited in claim 6, wherein said decrement detection comprises:

multiplying a current sample of the myoelectrical signal by a predetermined constant to produce a multiplied sample;

comparing the multiplied sample to a preceding sample of the myoelectrical signal; and

detecting said decrement when the amplitude, integral, derivative or combination thereof related to the multiplied sample is smaller than the amplitude, integral, derivative or combination thereof related to the preceding sample.

13. A device for triggering ventilatory support from a ventilatory apparatus connected to a patient'"'"'s respiratory-system to assist respiration of said patient, comprising:

sensor means for sensing myoelectrical activity of a respiratory-related muscle of the patient, to thereby detect respiratory effort of said patient;

means for calculating, in response to the sensed muscle myoelectrical activity, a real-time myoelectrical signal representative of a level or change in respiratory effort; and

means for activating/deactivating ventilatory support in relation to the myoelectrical signal to synchronise, in real-time, activating/deactivating of the ventilatory support to the patient with respiratory effort of said patient, said activating/deactivating means comprising;

means for comparing an amplitude, integral, derivative or combination thereof related to the myoelectrical signal to a given threshold; and

means for activating ventilatory support when said amplitude, integral, derivative or combination thereof is higher than said given threshold.

14. A device for triggering ventilatory support as recited in claim 13, further comprising means for filtering from the myoelectrical signal at least one of the following disturbances:

motion artifacts, ECG, electrical interference, and high frequency noise.

20. A device for triggering ventilatory support as recited in any one of claims 13, 15, 17, or 18 further comprising:

means for detecting a level of noise in the myoelectrical signal; and

means for determining whether the respiratory-related muscle of the patient is active in relation to the detected level of noise.

21. A device for triggering ventilatory support as recited in any one of claims 13, 15, 17 or 18, wherein:

the muscle myoelectrical activity sensing means comprises means for detecting myoelectrical activity of the respiratory-related muscle on two opposite sides of the center of a depolarizing region of said respiratory-related muscle; and

the real-time myoelectrical signal calculating means comprises;

means for generating two myoelectrical signal components in response to sensing of the myoelectrical activity of the respiratory-related muscle on the two opposite sides of the center of the depolarizing region, respectively, said two myoelectrical signal components having reversed polarities;

means for subtracting the two myoelectrical signal components from each other to produce a subtraction signal;

means for adding the two myoelectrical signal components to each other to produce an addition signal;

means for comparing the addition signal to the subtraction signal; and

means for accepting the subtraction signal as the real-time myoelectrical signal in relation to the comparison between the addition signal and the subtraction signal.

22. A device for triggering ventilatory support as recited in claim 21, wherein the subtraction signal, the addition signal, the multiplied addition signal and the myoelectrical signal comprise RMS signals.

23. A device for triggering ventilatory support as recited in claim 21, wherein:

the means for comparing the addition signal to the subtraction signal comprises means for multiplying the addition signal by a predetermined constant to produce a multiplied addition signal, and means for comparing the multiplied addition signal to the subtraction signal; and

the accepting means comprises means for accepting the subtraction signal as real-time myoelectrical signal when the subtraction signal has an amplitude, integral, derivative or combination thereof higher than an amplitude, integral, derivative or combination thereof related to the multiplied addition signal.

24. A device for triggering ventilatory support as in any of claims 13, 15, 17, or 18, further comprising:

a respiratory flow detector for measuring respiratory flow of the patient, and producing a respiratory flow signal;

a respiratory pressure detector for measuring respiratory pressure of the patient, and producing a respiratory pressure signal; and

a logic trigger circuit for triggering ventilatory support in relation to the myoelectrical signal, respiratory flow signal and/or respiratory pressure signal to assist respiration of the patient in response to respiratory effort of said patient.

15. A device for triggering ventilatory support from a ventilatory apparatus connected to a patient'"'"'s respiratory system to assist respiration of said patient, comprising:

sensor means for sensing myoelectrical activity of a respiratory-related muscle of the patient, to thereby detect respiratory effort of said patient;

means for calculating, in response to the sensed muscle myoelectrical activity, a real-time myoelectrical signal representative of a level or change in respiratory effort; and

means for activating/deactivating ventilatory support in relation to the myoelectrical signal to synchronise, in real-time, activating/deactivating of the ventilatory support to the patient with respiratory effort of said patient, wherein the activating/deactivating means comprises;

means for detecting an increment of an amplitude, integral, derivative or combination thereof related to the myoelectrical signal; and

means for activating ventilatory support in response to detection of said increment.

16. A device for triggering ventilatory support as recited in claim 15, wherein the increment detecting means comprises:

means for multiplying a current sample of the myoelectrical signal by a predetermined constant to produce a multiplied sample;

means for comparing the multiplied sample to a preceding sample of the myoelectrical signal; and

means for detecting said increment when the amplitude, integral, derivative or combination thereof related to the multiplied sample is higher than the amplitude, integral, derivative or combination thereof related to the preceding sample.

17. A device for triggering ventilatory support from a ventilatory apparatus connected to a patient'"'"'s respiratory system to assist respiration of said patient, comprising:

sensor means for sensing myoelectrical activity of a respiratory-related muscle of the patient, to thereby detect respiratory effort of said patient;

means for calculating, in response to the sensed muscle myoelectrical activity, a real-time myoelectrical signal representative of a level or change in respiratory effort; and

means for activating/deactivating ventilatory support in relation to the myoelectrical signal to synchronise, in real-time, activating/deactivating of the ventilatory support to the patient with respiratory effort of said patient, wherein the activating/deactivating means comprises;

means for comparing an amplitude, integral, derivative or combination thereof related to the myoelectrical signal to a given threshold; and

means for deactivating ventilatory support when said amplitude, integral, derivative or combination thereof is lower than said given threshold.

18. A device for triggering ventilatory support from a ventilatory apparatus connected to a patient'"'"'s respiratory system to assist respiration of said patient, comprising:

sensor means for sensing myoelectrical activity of a respiratory-related muscle of the patient, to thereby detect respiratory effort of said patient;

means for calculating, in response to the sensed muscle myoelectrical activity, a real-time myoelectrical signal representative of a level or change in respiratory effort; and

means for activating/deactivating ventilatory support in relation to the myoelectrical signal to synchronise, in real-time, activating/deactivating of the ventilatory support to the patient with respiratory effort of said patient, wherein the activating/deactivating means comprises;

means for detecting a decrement of an amplitude, integral, derivative or combination thereof related to the myoelectrical signal; and

means for deactivating the ventilatory support in response to detection of said decrement.

19. A device for triggering ventilatory support as recited in claim 18, wherein said decrement detecting means comprises:

means for multiplying a current sample of the myoelectrical signal by a predetermined constant to produce a multiplied sample;

means for comparing the multiplied sample to a preceding sample of the myoelectrical signal; and

means for detecting said decrement when the amplitude, integral, derivative or combination thereof related to the multiplied sample is smaller than the amplitude, integral, derivative or combination thereof related to the preceding sample.