DEVICE AND METHOD FOR DETERMINING AND/OR MONITORING THE RESPIRATORY EFFORT OF A SUBJECT

Abstract

A device and method for determining and/or monitoring the respiratory effort of a subject are presented. The device comprises a receiving unit for receiving a posture signal of the subject, a breathing signal of the subject, and an electromyography signal of the subject; and a processing unit for determining an electromyography signal based on the posture signal and the breathing signal and for deriving the respiratory effort based on the determined electromyography signal.

Claims

1. Device for determining and/or monitoring the respiratory effort of a subject, comprising: a receiving unit for receiving a posture signal of the subject, a breathing signal of the subject, and an electromyography signal of the subject; and a processing unit for determining the electromyography signal based on the received posture signal and the received breathing signal and for deriving the respiratory effort based on the determined electromyography signal.

2. Device according to claim 1, further comprising an accelerometer sensor for measuring the posture signal and the breathing signal of the subject.

3. Device according to claim 2, further comprising an electromyography patch for measuring the electromyography signal of the subject.

4. Device according to claim 3, wherein the electromyography patch is watertight.

5. Device according to claim 3, wherein a plurality of electromyography patches is used.

6. Device according to claim 1, wherein the receiving unit is further arranged for receiving a movement signal of the subject, wherein the processing unit is further configured to determine the electromyography signal based on the movement signal.

7. Device according to claim 1, wherein the receiving unit is further arranged for receiving a heart rate signal, wherein the processing unit is further configured to correct the determined electromyography signal based on the heart rate signal and to derive the respiratory effort based on the corrected determined electromyography signal.

8. Device according to claim 1, further comprising an indicating unit, wherein the indicating unit is configured to indicate the posture signal of the subject by indicating the position of the subject relative to an axis vertical to the ground.

9. Electromyography patch for determining and/or monitoring the respiratory effort of a subject, comprising: a first electrode and a second electrode, the first electrode and the second electrode coupled to the electromyography patch and adapted for contacting the skin of the subject; and at least one accelerometer sensor, wherein a distance between the first electrode and the second electrode corresponds to a distance between a right parasternal location of the subject and a left parasternal location of the subject.

10. Method for determining and/or monitoring the respiratory effort of a subject, comprising: receiving a posture signal of the subject, a breathing signal of the subject, and an electromyography signal of the subject; determining the electromyography signal based on the posture signal and the breathing signal; and deriving the respiratory effort based on the determined electromyography signal

11. Method according to claim 10, further comprising receiving a movement signal of the subject, wherein determining the electromyography signal is further based on the movement signal.

12. Method according to claim 10, further comprising receiving a heart rate signal, and correcting the determined electromyography signal on the heart rate signal and to derive the respiratory effort based on the corrected determined electromyography signal.

13. Method according to claim 10, wherein the electromyography signal is determined in the case the breathing signal is indicative for inhaling of the subject and the posture signal is indicative for a particular position of the subject relative to an axis vertical to the ground.

14. Method according to claim 10, wherein the method is for monitoring of a respiratory disorder.

15. Computer program comprising program code means for causing a computer or a processor to carry out the steps of the method as claimed in claim 10 when said computer program is carried out on the computer or the processor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. In the following drawings

[0059] FIG. 1 shows a schematic drawing of a subject having the correct posture for determining the respiratory effort;

[0060] FIG. 2 shows a cross section through an embodiment of a proposed EMG patch for use in the device and method according to the present invention;

[0061] FIG. 3 schematically shows an embodiment of a device according to the present invention for monitoring the respiratory effort of a subject; and

[0062] FIG. 4 shows an overview of intercostal spaces of the human body.

DETAILED DESCRIPTION OF THE INVENTION

[0063] FIG. 1 schematically shows a subject 50 or patient having an EMG patch 42 on its chest, preferably at a second intercostal space symmetrically with respect to the sternum for measuring parasternal muscle activity. The upper part of the body of subject 50 is placed in a correct position for determining the respiratory effort, wherein the angle 54 with respect to an axis vertical to the ground is 45 degrees according to this exemplary embodiment.

[0064] FIG. 2 is a cross section through an EMG patch which may be used for performing the proposed method and in connection with the proposed device 10. EMG patch 42 has a contacting surface to the human skin, wherein an electrical contact area 44 of patch 42 provides electrical contact to the skin of the subject 50. Patch 42 has further an accelerometer sensor 40 positioned in the center of the patch 42, above and spaced apart from the electrical contact area 44. One side of the contact area 44 is presented to the skin of the user 50, whereas the other side of the contact area 44 and accelerometer sensor 40 are watertightly embedded in silicone rubber material.

[0065] FIG. 3 schematically shows an embodiment of the device 10 for determining the respiratory effort according to the present invention. The device 10 comprises a receiving unit 20 for receiving a posture signal 30, a breathing signal 32, and an electromyography signal 34, 34a of the subject. Signals 30, 32, and 34 may be received from patch 42 shown in FIG. 2. In particular, posture signal 30 and breathing signal 32 are received from the accelerometer 40 and the electromyography signal 34 is received from the electrical contact area 44. Optionally a possible movement signal 36, and the heart rate signal 38 of the subject 50 are also received. The receiving unit 20 transmit the signals to a processing unit 22, which is configured to determine electromyography signal 34, 34a based on the posture signal and a breathing signal. Optionally, the electromyography signal 34a is also determined on the basis of the movement signal 36 which means that subject 50 does not move but remains quiescent. The heart rate signal 38 may be also employed for correcting the determined electromyography signal 34a. For this purpose, the effect of the heart rate signal is removed from the electromyography signal. In a next step the determined electromyography signal 34a representing activity of the parasternal muscle only, i.e. which is essentially free from disturbing signals arising from wrong posture, wrong time of subject's breathing cycle, any movement not related to breathing, and optionally artefacts from heartbeat. The determined electromyography signal may be taken as a direct measure of the respiratory effort, i.e. it represents a proportional value. The determined electromyography signal may be further used to calculate normalized neural respiratory drive.

[0066] FIG. 4 shows a schematic overview of intercostal spaces of subject 50. The left side shows external intercostal muscles 62 required for inhalation. The right side indicates internal intercostal muscles 66 required for exhalation. Accordingly, external intercostals 62 are only shown on the left side and internal intercostals 66 are only shown on the right side of FIG. 4. From this overview further position of scalenes 60 and diaphragm 68 may be derived. Preferred placement position for an electromyography patch is indicated by reference number 64, wherein 64a and 64b represent the two positions for contacting areas 44 of patch 42 to be placed at a second intercostal space, preferably symmetrically with respect to the sternum of patient 50. The right position 64b is not properly shown due to indication of internal intercostals 66 only. A single patch 42 may be used wherein the dimensions of the patch 42 correspond essentially to the borders of placement position 64 and the two points 64a and 64b indicate the position of contacting electrodes 44. The distance between 64a and 64b is the preferred distance for placing a single patch 42 with two contacting electrodes 44 or two patches 42 with one contacting electrode 44, respectively, particularly the right parasternal location and a left parasternal location of the subject 50.

[0067] In conclusion, the device and method presented herein reliably monitor respiratory effort of a subject. As an advantage, taking a posture signal and a breathing signal of the subject into account enable determining of a more accurate and reliable EMG signal. In addition, variability, an important confounder in serial EMG analysis where EMGs of the same individual, but taken at different times, is therefore reduced.

[0068] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

[0069] In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0070] A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

[0071] Any reference signs in the claims should not be construed as limiting the scope.