WO2024062486A1

WO2024062486A1 - System for measuring physiological parameters and a pressure applied on a surface thereof

Info

Publication number: WO2024062486A1
Application number: PCT/IL2023/051027
Authority: WO
Inventors: Guy OFEK; Eldad Shemesh
Original assignee: CardiacSense Ltd.
Priority date: 2022-09-22
Filing date: 2023-09-21
Publication date: 2024-03-28
Also published as: IL296760B1; IL296760A

Abstract

The present disclosure provides a system that allows measurement of a displacement or a deformation of a contact surface that is intended to contact skin of a subject. The purpose of the solution is either to allow a direct measurement of physiological parameters of the subject based on the displacement or the deformation measurement, or to allow compensation of sensed values of physiological parameters obtained during contact of the system with the sensed region, typically a skin of a subject, according to the pressure extent applied to the system during the contact of the sensed region. This is performed by sensing a change of pressure in a sealed volume of the system that is affected by the amount of pressure applied to the system.

Description

SYSTEM FOR MEASURING PHYSIOLOGICAL PARAMETERS AND A PRESSURE APPLIED ON A SURFACE THEREOF

TECHNOLOGICAL FIELD

The present disclosure is in the field of physiological parameters measurement devices.

BACKGROUND ART

References considered to be relevant as background to the presently disclosed subject matter are listed below:

- WO 2019/215723

- US 10849555

- US 2018146870

Acknowledgement of the above references herein is not to be inferred as meaning that these are in any way relevant to the patentability of the presently disclosed subject matter.

GENERAL DESCRIPTION

Therefore, an aspect of the present disclosure provides a system for measuring displacement or deformation of a contact surface portion of a contact member, the contact member being coupled to a system housing and configured for contacting skin portion of a subject. The system comprises an enclosure confining an internal volume substantially sealed for fluid exchange, in particular gas exchange, between it and the ambient surrounding. The term "substantially" should be interpreted that the volume is at least sealed for liquids, though there can be a minor and negligible exchange of gases between the internal volume and the ambient surrounding that does not have an effect on the functionality of the system. Namely, the pressure change as a result of the exchange of gas between the internal volume and the surrounding is in a much lower rate than the pressure change resulting by the displacement or the deformation of the contact surface. The enclosure is defined by (i) an enclosure housing portion and (ii) said contact surface portion. The contact surface portion can be either a portion that is intended to be contacted by a skin of a subject or a portion of the contact surface that is internal and part of a structure that includes a portion of the contact surface that is intended to be engaged by a skin of the subject. In other words, the enclosure is formed of two portions, a first portion that is constituted by a portion of the contact surface and a second portion that is constituted by the enclosure housing portion. The enclosure housing portion can be part of the system housing or independent therefrom. Pressure applied on the contact surface results in a volume change of the internal volume and therefore, pressure changes due to the fact that the internal volume is sealed. It is to be noted that the enclosure is further defined by portions that are not the contact surface. A fluid pressure sensor, either a gas pressure sensor or hydrostatic level sensor, is disposed within the internal volume, calibrated to a certain reference value, and configured to sense a change of pressure in the internal volume due to the change of the volume in response to pressure applied on the contact surface. The fluid pressure sensor is configured to generate fluid pressure data indicative of the change of pressure in the internal volume in response to the displacement or deformation of the contact surface and therefore indicative of the pressure applied on the contact surface.

It is to be noted that any combination of the described embodiments with respect to any aspect of this present disclosure is applicable. In other words, any aspect of the present disclosure can be defined by any combination of the described embodiments.

It is to be noted that if the system comprises a gas pressure sensor, the internal volume is filled with gas, and if the system comprises a liquid pressure sensor, the internal volume is filled with liquid.

In some embodiments of the system, said pressure data is indicative of at least one physiological parameter of the subject. In some embodiments of the system, said at least one physiological parameter is selected from: heart rate, respiration rate and blood pressure. Namely, the fluid pressure data comprises information that can be extracted therefrom to determine at least one physiological parameter.

In some embodiments, the system further comprises one or more physiological sensors that are coupled to the contact member, and may be coupled either directly or indirectly to the contact surface and configured to sense physiological parameters from a subject contacting the contact surface, Typically, a skin portion of the subject engages the contact surface, and the physiological sensors sense physiological parameters of the subject through the skin. The sensing of the physiological parameters can be made through the contact surface, for example by a PPG sensor that emits and receive light that propagates through the contact surface or directly from the skin such as an electrocardiography (ECG) sensor or galvanic skin response (GSR) sensor.

In some embodiments of the system, the one or more physiological sensors are selected from any one of: ECG sensor, PPG sensor, temperature sensor, galvanic skin response sensor or any combination thereof.

In some embodiments of the system, said one or more physiological sensors are configured to sense said physiological parameters through or from the contact surface. Namely, the sensors can be optically based, such as a PPG sensor, that emit light through the contact surface and detect the light that is returned from the skin of the subject contacting the contact surface, or can be electrically-based that are configured to detect electrical parameters by a direct contact of the skin of the subject with a sensing portion thereof, such as an ECG electrode.

In some embodiments of the system, at least one of the contact surface or a coupling of the contact surface to the system housing is configured to undergo a deformation upon application of pressure thereon. The deformation can be a minor deformation that is sufficient to change the pressure in the internal volume to result in a change of the reading of the fluid pressure sensor. Said deformation results in said volume change of the internal volume.

In some embodiments of the system, upon application of pressure on the contact surface, the contact surface is configured to move to result in said volume change of the internal volume. In some embodiments of the system, a part of said system housing defines at least a part of said enclosure housing portion. The system housing can include the entire enclosure housing portion or only a part thereof.

In some embodiments of the system, the fluid pressure sensor is a gas sensor.

In some embodiments of the system, the fluid pressure sensor is a barometric sensor.

In some embodiments of the system, the contact surface is coupled to the housing portion via a flexible member, the flexible member is characterized by having flexibility greater than the system housing, the enclosure housing and the contact surface. Namely, the flexible member is more flexible than the other parts of the enclosure and the system housing and it allows the contact surface to move with respect to the housing along at least one axis.

In some embodiments of the system, the enclosure is defined by the housing portion, the contact surface, and the flexible member. Namely, a part of the enclosure housing is defined by the flexible member.

In some embodiments of the system, a part of the system housing is defined by the flexible member.

In some embodiments of the system, the contact surface or the contact surface member has at least a portion being reversibly deformable such that pressure applied thereon causes it a reversible deformation resulting in said volume change of the internal volume.

In some embodiments, the system further comprises a processing circuitry configured to receive said fluid pressure data, such as barometric data indicative of pressure change within the internal volume and process it to determine pressure data indicative of pressure applied on the contact surface. The fluid pressure data can be the raw data that is derived from the fluid pressure sensor or any type of processed data of the signals derived from the barometric sensor.

In some embodiments of the system, the processing circuitry is configured to receive said fluid pressure data and process it to determine at least one physiological parameter, wherein said at least one physiological parameter is selected from: heart rate, respiration rate and blood pressure.

In some embodiments of the system, the processing circuitry is configured to apply temporal function to determine said pressure data or said at least one physiological parameter. The temporal function is applied on the signal received in a certain time window of the fluid pressure data.

In some embodiments of the system, the processing circuitry is configured to (i) receive sensed data obtained by the one or more physiological sensors and (ii) apply correction function, being dependent on the fluid pressure data, on the sensed data to correct sensed values determined from the one or more physiological sensors.

In some embodiments of the system, said correction function cancels the sensed values upon determination of pressure data exceeding a certain threshold.

In some embodiments of the system, the barometric sensor is configured to perform calibration upon receiving a calibration signal. The calibration comprises setting the ambient pressure value as the reference value in the internal volume at the time of receiving said calibration signal as a pressure reference value. Namely, that from the time of calibration until the next calibration process, the change of pressure within the internal volume will be measured from the new pressure reference value.

In some embodiments of the system, the calibration signal is provided when the system is coupled to a charging station for charging the system and the skin contact surface is in a neutral position with no pressure applied thereon.

In some embodiments of the system, the calibration signal is provided periodically, namely after a certain constant or about constant amount of time.

In some embodiments, the system further comprises a supporting structure coupling the system housing to a part of the enclosure housing portion, thereby providing a counter force for allowing the resulting of the volume change of the internal volume.

In some embodiments of the system, the contact surface portion is an internal part of the contact surface, that may be an internal part of a contact surface member that faces the internal volume. Upon application of force on the contact surface, the contact surface portion is pressed or deformed to thereby result in the change of the internal volume.

Yet another aspect of the present disclosure provides a medical watch comprising the system of any one of the above-described embodiments or any combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Fig. 1 is a schematic illustration of a cross-sectional view of a non-limiting example of an embodiment of the system according to an aspect of the present disclosure, in which the contact surface member is deformable.

Fig. 2 is a schematic illustration of a cross-sectional view of a non-limiting example of an embodiment of the system according to an aspect of the present disclosure, in which the contact surface member is displaceable due to being coupled to the housing portion via a flexible member.

Fig. 3 is a schematic illustration of a cross-sectional view of a non-limiting example of a medical watch that the system according to an aspect of the present disclosure.

Fig. 4 is a schematic illustration of a cross-sectional view of a non-limiting example of an embodiment of the system according to an aspect of the present disclosure.

Figs. 5A-5B show a comparison of exemplary temporal measurements of two pressure sensors sensing a pressure applied on the contact surface, a prior art sensor measurement on the left side of each figure, and a measurement by the system of the present disclosure on the right side of each figure.

Fig. 6 is a schematic illustration of a cross-sectional view of a non-limiting example of an embodiment of the system according to an aspect of the present disclosure.

DETAILED DESCRIPTION

The following figures are provided to exemplify embodiments and the realization of the invention of the present disclosure.

Fig. 1 is a schematic illustration of a cross-sectional view of a non-limiting example of an embodiment of the system according to an aspect of the present disclosure. The system 100, being a part of or suitable for incorporation in a measuring device such as a medical watch or medical wrist, comprises an enclosure 102. The enclosure 102 comprises an enclosure housing portion 104 and a portion of a contact surface 106 of the system 100 that is coupled to the enclosure housing portion 104 and defining therewith the external contour of the enclosure 102. In this example, the enclosure housing portion 104 is part of the housing of the system 100. The enclosure 102 defines an internal volume 108 that is sealed for exchange of fluids, i.e. gas and liquid, with the ambient surrounding. A gas leak may occur, but the rate of the gas leak for obtaining a pressure equilibrium is significantly lower than the change of the pressure that results in response to displacement or deformation of the contact surface, typically at least a magnitude of order less, and therefore does not affect the measurement operation of the system. A barometric sensor 110 is disposed within the internal volume 108 and is configured to sense pressure changes within the internal volume 108 over time. While this embodiment exemplifies the user of a barometric sensor, it is to be noted that any fluid pressure sensor can be used. The barometric sensor is configured to be set with a reference pressure value upon receiving a calibration signal. This can occur, for example, periodically at defined time intervals or when the system is positioned in a neutral position such as when it is being charged when no pressure is applied on the contact surface 106.

The contact surface 106 is a part of a contact surface member 112 that accommodates physiological sensors 114. The physiological sensors 114 can be formed on the contact surface to sense parameters directly from the skin of the subject, such as electrocardiography (ECG) sensors or galvanic skin response (GSR) sensors, or they can be disposed in a position that performs the sensing of the parameters through the contact surface 106, such as PPG sensor that includes a light source (e.g. a LED) and a light detector (e.g. a photodiode).

In this example, the contact surface member 112 is configured to be reversibly deformed or to reversibly displaced upon application of pressure thereon, i.e. on the contact surface 106, resulting in a change of the volume of the internal volume 108 that is translated into a change of the internal pressure of the internal volume 108 that is sensed by the barometric sensor 110. Therefore, the reading of the pressure change by the barometric sensor 110 is indicative of the pressure applied on the contact surface 106 and the deformation or displacement of the contact surface.

The system may further comprise a processing circuitry (not shown) that is configured to receive the sensed data from all the physiological sensors 114 and the barometric data sensed by the barometric sensor 110. The processing circuitry is configured to process the sensed data and the barometric data and provide an output that is indicative of either the sensed parameters that are sensed by the physiological sensors 114 and/or determined physiological parameters based on the barometric data. The output can be displayed on a screen of the system or transmitted to a remote unit to be displayed thereby. The processing circuitry is configured to apply correction function on the sensed data, the correction function is generated based on the barometric data and can be varied according to different values of the barometric data. The correction function adjusts the values of the parameters in the sensed data. In some embodiments, the adjustment can be cancellation of the measured value if a pressure exceeding a certain value is sensed by the barometric sensor.

In the figures throughout the application, like elements of different figures were given similar reference numerals shifted by the number of hundreds corresponding to the number of the respective figure. For example, element 202 in Fig. 2 serves the same function as element 102 in Fig. 1.

Reference is now being made to Fig. 2, which shows a schematic illustration of a cross-sectional view of another non-limiting example of an embodiment of the system according to an aspect of the present disclosure. The system 200 shown in Fig. 2 differs from that of Fig. 1 in that the contact surface member 212 is rigid and non-deformable and it is coupled to the housing portion 204 by a flexible member 216 that is more flexible than the enclosure housing portion 204 and the contact surface member 212 so as to allow a movement of the contact surface member 212 with respect to the enclosure housing portion 204, at least along an axis Z defined normal to the plane defined by the contact surface 206. The external contour of the enclosure 202 of the system 200 is defined by the enclosure housing portion 204, the flexible member 216 and the contact surface 206. While pressure is applied on the contact surface 206, the contact surface member 212 moves into the internal volume 208 and decreases it, which results in an increase of the internal pressure that is sensed by the barometric sensor 210 that is disposed in the internal volume 208.

The physiological sensors 214 are accommodated in the contact surface member 212 in a similar manner to that of Fig. 1.

Reference is now being made to Fig. 3, which is a schematic illustration of a cross- sectional view of a non-limiting example of a medical watch that the system according to an aspect of the present disclosure. The medical watch 320 comprises a system housing 322 that accommodates the system described in Fig. 1. Wristband 324 is coupled to the system housing 322 allowing fixing the medical watch 320 on a wrist of a subject. The medical watch may further comprises a screen 326 for presenting the physiological parameters sensed by the system. The system housing 322 comprises a part 323 of the enclosure housing portion 304, and there are other parts of the enclosure housing portion 304 that are independent and not part of the system housing 322.

Reference is now being made to Fig. 4, which is a schematic illustration of a cross- sectional view of a non-limiting example of an embodiment of the system according to an aspect of the present disclosure. The example of Fig. 4 differs from that of Fig. 1 by that the enclosure housing portion 404, namely the portion of the enclosure 402 that is not part of the contact surface 406, is not part of other housing. In other words, the enclosure is fixed to the contact surface member 412, in an opposite side of the contact surface 406 and includes its independent housing portion. In order to provide a counter force to allow a change in the internal volume 408, a supporting structure 430 coupling a part of the enclosure housing portion 404 to the system housing 422. In this embodiment, the barometric sensor 412 is fixed to the contact surface member 412 such that it can be electrified by a PCB that is part of the contact surface member 412.

Reference is now being made to Fig. 6, which a schematic illustration of a cross- sectional view of a non-limiting example of an embodiment of the system according to an aspect of the present disclosure. The system 600, being a part of or suitable for incorporation in a measuring device such as a medical watch or a medical wrist, comprises an enclosure 602. The enclosure 602 comprises an enclosure housing portion 604 and a contact surface portion 605 of a contact surface 606 of a contact surface member 612 of the system 100 that is coupled to the enclosure housing portion 604 and defining therewith the external contour of the enclosure 602. In this example, the enclosure housing portion 604 is part of the housing of the system 600. The enclosure 602 defines an internal volume 608 that is sealed for the exchange of fluids, i.e. gas and liquid, with the ambient surrounding. A gas leak may occur, but the rate of the gas leak for obtaining a pressure equilibrium is significantly lower than the change of the pressure that results in response to displacement or deformation of the contact surface, typically at least a magnitude of order less, therefore does not affect the measurement operation of the system. A barometric sensor 610 is disposed within the internal volume 608 and is configured to sense pressure changes within the internal volume 608 overtime. While this embodiment exemplifies the user of a barometric sensor, it is to be noted that any fluid pressure sensor can be used. The barometric sensor is configured to be set with a reference pressure value upon receiving a calibration signal. This can occur, for example, periodically at defined time intervals or when the system is positioned in a neutral position such as when it is being charged when no pressure is applied on the contact surface 606.

In this example, the contact surface member 612 is configured to be reversibly deformed or to reversibly displaced upon application of pressure thereon, i.e. on the contact surface 606, resulting in a change of the volume of the internal volume 608 that is translated into a change of the internal pressure in the internal volume 608 that is sensed by the barometric sensor 610. Therefore, the reading of the pressure change by the barometric sensor 610 is indicative of the pressure applied on the contact surface 606 and the displacement or the deformation of the contact surface member 612.

Optionally, the system may further comprise a processing circuitry (not shown) that is configured to receive the barometric data sensed by the barometric sensor 610. The processing circuitry is configured to process the barometric data and provide an output that is indicative of physiological parameters of a subject contacting the contact surface 606. The output can be displayed on a screen of the system or transmitted to a remote unit to be displayed thereby.

It is to be noted that any one of the embodiments exemplified in Figs. 1, 3-4, 6 or any combination thereof may be incorporated into a watch or any other measuring device.

Figs. 5A-5B show examples of temporal measurements of two pressure sensors sensing a pressure applied on the contact surface. On the left side of each figure presented a measurement performed by a prior art sensor based on optical measurement, and on the right side of each figure presented a measurement by the system of the present disclosure using a barometer to sense the applied pressure . These figures clearly show that the signal to noise ratio of the measurements of the system of the present disclosure and the quality of the signal is improved with respect to the prior art.

Claims

CLAIMS:

1. A system for measuring displacement or deformation of a contact surface portion of a contact member coupled to a system housing configured for contact with skin portion of a subject, comprising: an enclosure confining an internal volume substantially sealed from fluid exchange between it and its surrounding, said enclosure being defined by (i) an enclosure housing portion and (ii) said contact surface portion, the displacement or the deformation of the contact surface portion resulting in a volume change of the internal volume; a fluid pressure sensor disposed within the internal volume and configured to sense a change of pressure in the internal volume and generate fluid pressure data based thereon indicative of said displacement or deformation.

2. The system of claim 1, wherein said pressure data is indicative of at least one physiological parameter of the subject.

3. The system of claim 2, wherein said physiological parameter is selected from: heart rate, respiration rate and blood pressure.

4. The system of any one of claims 1-3, comprising one or more physiological sensors coupled to the contact member and configured to sense physiological parameters of the subject contacted by the contact surface.

5. The system of claim 4, wherein said one or more physiological sensors are selected from any one of: ECG sensor, PPG sensor, temperature sensor, galvanic skin response sensor or any combination thereof.

6. The system of claim 5, wherein said one or more physiological sensors are configured to sense said physiological parameters through or from the contact surface.

7. The system of any one of claims 1-4, wherein a coupling of the contact surface to the housing is configured to undergo a deformation upon application of pressure thereon, wherein said deformation results in said volume change of the internal volume.

8. The system of any one of claims 1-5, wherein the contact surface is configured to move upon application of pressure on the contact surface, resulting in the volume change of the internal volume.

9. The system of claim 6, wherein the contact surface is coupled to the housing portion via a flexible member having flexibility greater than the system housing, the enclosure housing and the contact surface.

10. The system of claim 8, wherein part of the enclosure housing is defined by the flexible member.

11. The system of any of claims 1-8, wherein a part of said system housing defines at least a part of said enclosure housing portion.

12. The system of any one of claims 1-9, wherein the contact surface member has at least a portion being reversibly deformable such that pressure applied thereon results in said volume change of the internal volume.

13. The system of any one of claims 1-12, comprising a processing circuitry configured to receive said fluid pressure data and process it to determine pressure data indicative of pressure applied onto the contact surface.

14. The system of any one of claims 1-13, wherein the processing circuitry is configured to receive said fluid pressure data and process it to determine at least one physiological parameter, wherein said at least one physiological parameter is selected from: heart rate, respiration rate and blood pressure.

15. The system of claim 13 or 14, wherein the processing circuitry is configured to apply temporal function to determine said pressure data or said at least one physiological parameter.

16. The system of any one of claims 13-15, wherein the processing circuitry is configured to (i) receive sensed data obtained by the one or more physiological sensors and (ii) apply correction function, being dependent on the fluid pressure data, on the sensed data to correct sensed values determined from the one or more physiological sensors.

17. The system of claim 16, wherein said correction function cancels the sensed values upon determination of pressure data exceeding a certain threshold.

18. The system of any one of claims 1-17, wherein the fluid pressure sensor is a gas pressure sensor.

19. The system of claim 18, wherein the gas pressure sensor is a barometric sensor.

20. The system of any one of claims 1-19, comprising a supporting structure coupling the system housing to a part of the enclosure housing portion.

21. A medical watch comprising the system of any one of claims 1-20.