An apparatus and a method for measuring jugular vein pressure waveform

Abstract

An apparatus for measuring a jugular vein pressure waveform includes a rotation sensor (102) configured to generate a measurement signal when it is in contact with a person's skin and in a motion-sensing relationship with a jugular vein (104) of that person. The apparatus includes a processing system (101) configured to receive the measurement signal and, based on the measurement signal indicating rotation of the rotation sensor, generate a waveform of a movement of the skin in a direction perpendicular to the skin, wherein the waveform of the skin's movement indicates the jugular vein pressure waveform. Compared to, for example, an accelerometer, the rotation sensor measuring rotation is less sensitive to movement unrelated to changes in the jugular vein pressure.

Description

[Technical Field]

[0001] This invention relates to an apparatus and method for measuring the jugular venous pressure (JVP) waveform. The measured jugular venous pressure waveform can be used, for example, to detect pulmonary hypertension (PAH). [Previous Technology]

[0002] Undiagnosed and untreated / unmanaged abnormalities in the cardiovascular system can lead to a gradual deterioration of an individual's health. For example, in many cases, pulmonary hypertension (PAH) represents an early indication of an impending worsening stage of heart failure, which typically occurs within three to four weeks of the onset of pulmonary hypertension. In many cases, pulmonary hypertension can predict the worsening stage of heart failure very early, thus typically lacking traditional signs of heart failure such as weight gain and elevated blood pressure. Early diagnosis of heart failure usually allows for treatment and / or intervention, significantly reducing mortality and hospitalization requirements.

[0003] Examinations related to the behavior of the jugular vein (Latin: vena jugularis) represent a useful tool for diagnosing conditions such as heart failure. Changes in jugular vein pressure arise from changes in blood flow and pressure in the central vein caused by the filling and contraction of the right atrium and right ventricle of the heart. The jugular vein connects directly to the right atrium, thus enabling non-invasive examination of the right side of the heart (i.e., the right ventricle and right atrium). Publication US2019254542 describes a venous pressure monitoring system configured to determine central venous pressure (CVP) based on jugular vein pressure (JVP). The venous pressure monitoring system described in US2019254542 includes a signal processor, at least one accelerometer, at least one display, and at least one patch adapted to be held in place or otherwise secured to an individual's neck. The signal processor communicates with at least one accelerometer to calculate an estimate of the central venous pressure. An inherent challenge associated with systems based on one or more accelerometers as described above is that the output signal of each accelerometer includes not only a signal component generated by changes in jugular venous pressure, but also a signal component generated by movement unrelated to changes in jugular venous pressure. The latter signal component affects the accuracy of central venous pressure estimation.

[0004] The publication Bagyaraj, S., Ragumathulla, M., Vaithiyanathan, D.: Acquisition of Jugular Venous Pulse Waveform by a Non-invasive Technique, Recent advances in mechanical engineering, Lecture notes in mechanical engineering. Springer, Singapore, January 25, 2020 describes a method for measuring jugular venous pressure (JVP) using an accelerometer. The publication Baumann, U., Marquis, C., Stoupis, C., Willenberg, T., Takala, J. & Jakob, S.: Estimation on central venous pressure by ultrasound, Resuscitation 64(2), pp. 193-199, February 1, 2005 describes a method for estimating central venous pressure (CVP) using ultrasound signals.

[0005] Publication US2018184977 describes a method for measuring jugular vein properties. The method includes coupling a device including an imager to a patient's neck, using the imager to image the jugular vein at an imaging location, and analyzing at least one image provided by the imager to estimate at least one property of the jugular vein. Publication US2012136240 describes a system for detecting and measuring elevated global or local intracranial pressure. The system includes a device for performing controlled occlusion of jugular vein outflow and generating occlusion data associated with the controlled occlusion, an intracranial blood flow pressure measuring device, and a processor for processing the jugular vein outflow occlusion data and intracranial blood flow data to identify and / or measure the functional relationship between the controlled occlusion of the jugular vein and the jugular vein intracranial blood flow pressure. Publication WO2008098353 describes a device for non-invasively measuring at least one parameter of the cardiovascular system. The device includes at least one light source emitting light in the wavelength range of 400 nm to 1000 nm, at least one photodetector adapted to receive light from patient tissue near the heart vessels and generate an output based on the received light, and at least one probe for transmitting light from the light source to the patient tissue. US Publication US2012197118 describes an ultrasound monitoring device for measuring physiological parameters in mammals. The ultrasound monitoring device includes a substrate, a plurality of ultrasound transducer elements, computer-readable memory, a microprocessor, and a power supply. The ultrasound transducer elements are coupled to the substrate. Each ultrasound transducer element is configured to transmit a signal to a target region of the mammal and receive an echo return signal from the target region. Publication WO2018161159 describes a device for measuring jugular venous pressure in a patient. The device includes: a body defining a longitudinal housing and having a window along the length of the longitudinal housing to allow light to exit from the longitudinal housing; and a beam generator including a movable portion mounted within the longitudinal housing. The beam generator is configured to produce a beam of light along a plane perpendicular to the longitudinal direction and at an adjustable position in the longitudinal direction, and guides the beam of light out of a window. The device further includes an adjustment mechanism for adjusting the position of a movable portion of the beam generator relative to the body in the longitudinal direction, and a readout device indicating the position of the beam of light in the longitudinal direction. Publication US2010094141 describes a jugular venous pressure (JVP) scale and a method for measuring the jugular venous pressure of a patient. The JVP scale includes a transducer configured to detect displacement of the patient's skin. [Summary of the Invention]

[0006] The following is a simplified overview to provide a basic understanding of some aspects of various embodiments of the present invention. This overview is not an exhaustive summary of the invention. It is not intended to identify key or defining elements of the invention, nor to describe the scope of the invention. The following overview presents some concepts of the invention in a simplified form only as a prelude to a more detailed description of exemplary embodiments of the invention.

[0007] In this document, the term "geometry" as a prefix means a geometric concept that is not necessarily part of any physical object. A geometric concept can be, for example, a geometric point, a straight or curved geometric line, a geometric plane, a non-planar geometric surface, a geometric space, or any other geometric entity that is zero-dimensional, one-dimensional, two-dimensional, or three-dimensional.

[0008] According to the present invention, a novel device is provided for measuring the jugular venous pressure (JVP) waveform. The measured jugular venous pressure waveform can be used, for example, to detect pulmonary hypertension (PAH).

[0009] An apparatus according to the present invention comprises: - a rotation sensor, such as a gyroscope, configured to generate a measurement signal indicating rotation of the rotation sensor when it is in contact with a skin of an individual and in a motion sensing relationship with a jugular vein of the individual; and - a processing system configured to receive the measurement signal and generate a waveform of a movement of the skin in a direction perpendicular to the skin based on the measurement signal, wherein the waveform of the movement of the skin indicates a jugular vein pressure waveform, the processing system configured to calculate an angular displacement of the rotation sensor based on the measurement signal, wherein the angular displacement represents the waveform of the movement of the skin in the direction perpendicular to the skin.

[0010] The rotation sensor is advantageously positioned such that one end of the rotation sensor is closer to the jugular vein than the other end. Therefore, changes in jugular vein pressure cause more movement at the first mentioned end of the rotation sensor than at the last mentioned end, and this difference manifests as rotational movement of the rotation sensor. Movements unrelated to jugular vein pressure and having substantially the same amplitude and direction across the entire skin area covered by the rotation sensor do not cause significant rotational movement of the rotation sensor, but only translational movement, and thus, this movement does not produce a significant signal component in the output signal of the rotation sensor. Therefore, compared to, for example, an accelerometer measuring translational movement, a rotation sensor measuring rotation is less sensitive to many movements unrelated to changes in jugular vein pressure.

[0011] The pulsation caused by the jugular vein differs from that caused by the carotid artery. This is due to the structural differences between the thin-walled, flexible jugular vein and the thick-walled, muscular carotid artery, and also because of the different pressures in the jugular vein and carotid artery. The pressure in the jugular vein is approximately 10 mmHg, while the pressure in the carotid artery is approximately 100 mmHg. Experiments show that the signal generated by the rotation sensor is purely from the jugular vein, while the signal generated by the accelerometer is a mixture of signals from both the jugular vein and carotid artery. This can be explained by the differences in the types of movement measured by the rotation sensor and the accelerometer, as well as the differences in the types of movement caused by the jugular vein and carotid artery. The jugular vein causes localized movement in the tissue covering it, while the carotid artery causes sharper pulses, resulting in translational movement over a larger area. As previously mentioned in this document, movement unrelated to jugular venous pressure and having substantially the same amplitude and direction over a large area of ​​skin does not cause significant rotational movement on the rotation sensor, but only translational movement. Consequently, this movement does not produce a significant signal component in the output signal of the rotation sensor. Therefore, the rotation sensor is less sensitive to movement caused by the carotid artery compared to, for example, an accelerometer that measures translational movement.

[0012] The advantage of a rotation sensor over an optical sensor is that an optical sensor can only measure pulsations caused by the external jugular vein, and therefore must be precisely positioned to cover the external jugular vein, which complicates its use. A rotation sensor measures pulsations primarily caused by the internal jugular vein, and therefore the positioning requirements are less stringent than when using an optical sensor.

[0013] According to the present invention, a novel method for measuring jugular venous pressure (JVP) waveforms is provided. A method according to the present invention includes: - generating a measurement signal by a rotation sensor abutting against a skin of an individual and in a motion-sensing relationship with a jugular vein of the individual; and - generating a waveform of a movement of the skin in a direction perpendicular to the skin based on the measurement signal indicative of rotation of the rotation sensor, the waveform of the skin movement indicating a jugular venous pressure waveform, wherein the method includes calculating an angular displacement (φ) of the rotation sensor based on the measurement signal, wherein the angular displacement represents the waveform of the movement of the skin in the direction perpendicular to the skin.

[0014] Illustrative and non-limiting embodiments are described in the appended claims.

[0015] Various exemplary and non-limiting embodiments of the construction and operation methods, together with their additional objectives and advantages, will be best understood from the following description of particular exemplary embodiments when read in conjunction with the accompanying drawings.

[0016] The verbs “contain” and “include” are used in this document as an openness restriction, which neither excludes nor requires the existence of undescribed features.

[0017] Unless otherwise expressly stated, the features described in the appended claims may be freely combined with each other. Furthermore, it should be understood that the use of "a," i.e., the singular form, in this document does not preclude a plural.

Implementation Method

[0019] The specific examples provided in the following description should not be construed as limiting the scope and / or applicability of the appended patent application. Unless otherwise expressly stated, the list and groups of examples provided in the description are not exhaustive.

[0020] Figure 1 illustrates an apparatus for measuring a jugular venous pressure (JVP) waveform according to an exemplary and non-limiting embodiment. The apparatus includes a rotation sensor 102, such as a gyroscope, configured to generate a measurement signal indicating the rotation of the rotation sensor 102 when it is in motion sensing relationship with the skin 103 of an individual 107 and with the jugular vein 104 of the individual. The rotation sensor 102 may be, for example, part of a mobile phone placed against the skin of the individual 107. The apparatus includes a processing system 101 configured to receive the measurement signal and, based on the measurement signal, generate a waveform representing the movement of the skin 103 in a direction perpendicular to the skin. The waveform representing the movement of the skin indicates the jugular venous pressure (JVP) waveform. In portion 120 of Figure 1, the direction perpendicular to the skin 103 is substantially parallel to the z-axis of coordinate system 199. The processing system 101 may be, for example, part of a mobile phone. Furthermore, the processing system 101 and the rotation sensor 102 can both be, for example, parts of the same mobile phone. In this exemplary case, the mobile phone constitutes a device for measuring the jugular venous pressure "JVP" waveform. In the exemplary case illustrated in FIG1, the waveform of the movement of the skin 103 is expressed by the time change of the rotation angle φ of the rotation sensor 102, and thus the jugular venous pressure "JVP" waveform. The device may include, for example, a display for displaying the measured jugular venous pressure "JVP" waveform. The display is not shown in FIG1. ​​The device may also include a data transmission interface for supplying data expressing the jugular venous pressure "JVP" waveform to an external device. This data transmission interface is not shown in FIG1.

[0021] In the device according to the exemplary and non-limiting embodiments, the rotation sensor 102 is configured to measure the angular velocity ω of the rotation sensor 102, and the processing system 101 is configured to calculate the time integral of the angular velocity: (1) wherein the angular velocity ω of the rotation sensor 102 represents the measurement signal, and the time integral of the angular velocity, i.e. the angular displacement φ, indicates the jugular venous pressure "JVP" waveform.

[0022] In the device according to the exemplary and non-limiting embodiments, the rotation sensor 102 is configured to measure the angular acceleration α of the rotation sensor 102, and the processing system 101 is configured to calculate a first time integral I1 as the time integral of the angular acceleration α and a second time integral I2 as the time integral of the first time integral: (2)(3) wherein the angular acceleration α of the rotation sensor 102 represents the measurement signal, and the second time integral I2, i.e. the angular displacement φ, indicates the jugular venous pressure "JVP" waveform.

[0023] The rotation sensor 102 (e.g., a gyroscope) is configured to measure the angular velocity ω. The aforementioned embodiment is advantageous in that it only requires one time integration to obtain the waveform of the skin's angular displacement φ. Time integration has a low-pass filtering effect, and therefore requiring only one time integration is advantageous. For example, in the case of using an accelerometer, the waveform of the angular displacement φ can be obtained by means of trigonometric functions, but the need for two time integrations will degrade the measurement quality, and in addition, the need for trigonometric functions will complicate data processing.

[0024] In the device according to the exemplary and non-limiting embodiments, the processing system 101 is configured to receive electrical signals from electrodes 105 and 106 on the skin of the individual 107, and the processing system 101 is configured to generate an electrocardiogram (ECG) for the time interval of the jugular venous pressure waveform, that is, the jugular venous pressure waveform and the ECG are synchronized with each other.

[0025] The device according to the exemplary and non-limiting embodiments may also include two or more rotation sensors for measuring the same jugular vein to improve accuracy. Furthermore, one or more rotation sensors of the device according to the exemplary and non-limiting embodiments may be one or more implants placed under the skin. The implants may utilize radio frequency identification (RFID) technology to transmit measurement signals from the implant to the device's processing system.

[0026] Figure 2a shows an exemplary jugular venous pressure waveform 210 and an exemplary electrocardiogram 211 generated by the device according to the exemplary and non-limiting embodiments. The jugular venous pressure waveform 210 and the electrocardiogram 211 are measured simultaneously.

[0027] In the device according to the exemplary and non-limiting embodiments, the processing system 101 is configured to generate an indicator signal expressing pulmonary hypertension "PAH" in response to the a-wave of the jugular venous pressure waveform exceeding a predetermined threshold value. The a-wave of the jugular venous pressure waveform 210 is illustrated in Figure 2a. An increase in the a-wave is characteristic of pulmonary hypertension "PAH," which is caused by an increase in flow resistance through the pulmonary valve to the pulmonary artery. This is reflected in the jugular vein via the right atrium.

[0028] Figure 2b shows an exemplary waveform of angular displacement generated by a device according to an illustrative and non-limiting embodiment. In this exemplary case, the device includes a gyroscope configured to measure angular velocity, and therefore, the waveform of angular displacement can be obtained with only one time integration. As shown in Figure 2b, the waveform of angular displacement obtained by means of the gyroscope can represent the a-wave, c-wave, h-wave, and v-wave. Figure 2c shows a displacement waveform obtained by two time integrations based on a signal measured by an accelerometer in a direction perpendicular to the skin. As shown in Figure 2c, the a-wave, c-wave, h-wave, and v-wave cannot be identified from the waveform obtained by the accelerometer.

[0029] Figure 3 illustrates an apparatus for measuring a jugular venous pressure (JVP) waveform according to an exemplary and non-limiting embodiment. The apparatus includes a rotation sensor 302, such as a gyroscope, configured to generate a measurement signal indicating the rotation of the rotation sensor 302 when the rotation sensor 302 is in motion sensing relationship with the individual's skin 303 and jugular vein 304. The apparatus includes a processing system 301 configured to receive the measurement signal and generate a waveform representing the motion of the skin 303 in a direction perpendicular to the skin based on the measurement signal. In Figure 3, the direction perpendicular to the skin 303 is substantially parallel to the z-axis of coordinate system 399. The waveform of the skin motion indicates the jugular venous pressure (JVP) waveform. In the exemplary configuration illustrated in Figure 3, the waveform of the skin 303 motion, and thus the jugular venous pressure (JVP) waveform, is expressed by the time change of the rotation angle φ of the rotation sensor 302.

[0030] The exemplary device illustrated in Figure 3 includes a flexible material sheet 308 with an adhesive to attach the rotation sensor 302 to the individual's skin 303. Therefore, the device can be used in different individual positions, such as when the individual is standing.

[0031] In the exemplary device illustrated in FIG3, the processing system 301 and the rotation sensor 302 are configured to maintain a wireless link to transmit measurement signals from the rotation sensor 302 to the processing system 301. The wireless link may be, for example, a radio link, such as a Bluetooth® link or a near field communication "NFC" link. The wireless link may also be an optical or infrared link.

[0032] Each of the processing systems 101 and 301 shown in Figures 1 and 3 may be implemented, for example, by one or more processor circuits, each of which may be a programmable processor circuit with appropriate software, a dedicated hardware processor such as an application-specific integrated circuit (ASIC), or a configurable hardware processor such as a field-programmable gate array (FPGA). Each of the processing systems 101 and 301 may further include memory, for example, implemented by one or more memory circuits, each of which may be, for example, a random access memory (RAM) device.

[0033] Figure 4 shows a flowchart of a method for measuring a jugular vein pressure "JVP" waveform according to an exemplary and non-limiting embodiment. The method includes the following actions: - Action 401: generating a measurement signal by means of a rotation sensor that is against the skin of an individual and in motion sensing relationship with the jugular vein of the individual, and - Action 402: generating a waveform of the movement of the skin in a direction perpendicular to the skin based on the measurement signal indicating the rotation of the rotation sensor, the waveform of the skin movement indicating the jugular vein pressure waveform.

[0034] In the method according to the exemplary and non-limiting embodiments, a rotation sensor measures the angular velocity of the rotation sensor, and the method includes calculating the time integral of the measured angular velocity. The measured angular velocity of the rotation sensor represents the measurement signal mentioned above, and the time integral of the measured angular velocity indicates the jugular venous pressure waveform.

[0035] In the method according to the exemplary and non-limiting embodiments, a rotation sensor measures the angular acceleration of the rotation sensor, and the method includes calculating a first time integral as a time integral of the measured angular acceleration and a second time integral as a time integral of the first time integral. The measured angular acceleration of the rotation sensor represents the measurement signal mentioned above, and the second time integral indicates the jugular vein pressure waveform.

[0036] The method according to the exemplary and non-limiting embodiments includes receiving one or more electrical signals from electrodes on the individual's skin and generating an electrocardiogram for time intervals of jugular venous pressure waveforms.

[0037] In the method according to the exemplary and non-limiting embodiments, the measurement signal is received via a wireless link self-rotation sensor.

[0038] The method according to the exemplary and non-limiting embodiments includes generating an indicator signal expressing pulmonary hypertension "PAH" in response to the a wave of the jugular venous pressure waveform exceeding a predetermined threshold value.

[0039] The specific examples provided in the description above should not be construed as limiting the scope and / or applicability of the appended claims. Unless otherwise expressly stated, the list and groups of examples provided in the description above are not exhaustive. Correspondingly, the illustrative waveforms and other illustrative results presented in the above and / or figures should not be construed as limiting the scope and / or applicability of the appended claims. [Simplified Explanation of the Diagram]

[0018] The exemplary and non-limiting embodiments and their advantages are explained in more detail below with reference to the accompanying drawings, in which: [Figure 1] illustrates an apparatus for measuring the jugular venous pressure "JVP" waveform according to an exemplary and non-limiting embodiment; [Figure 2a] shows an exemplary waveform generated by the apparatus according to the exemplary and non-limiting embodiment; [Figure 2b] shows an exemplary waveform of angular displacement generated by the apparatus according to the exemplary and non-limiting embodiment; [Figure 2c] shows a corresponding waveform of displacement generated by an accelerometer; [Figure 3] illustrates an apparatus for measuring the jugular venous pressure "JVP" waveform according to an exemplary and non-limiting embodiment; and [Figure 4] shows a flowchart of a method for measuring the jugular venous pressure "JVP" waveform according to an exemplary and non-limiting embodiment.

Claims

1. An apparatus for measuring a jugular venous pressure waveform, the apparatus comprising a processing system (101, 301) and a rotation sensor (102, 302), the processing system being configured to receive a measurement signal, the rotation sensor being configured to generate the measurement signal indicating rotation of the rotation sensor when in contact with a skin of an individual and in a motion sensing relationship with a jugular vein of the individual, and the processing system being configured to generate a waveform of a movement of the skin in a direction perpendicular to the skin based on the measurement signal, the waveform of the movement of the skin indicating the jugular venous pressure waveform, wherein the processing system being configured to calculate the angular displacement (φ) of the rotation sensor based on the measurement signal, wherein the angular displacement represents the waveform of the movement of the skin in the direction perpendicular to the skin, characterized in that the processing system being configured to generate an indicator signal expressing pulmonary hypertension in response to a condition in which an a-wave of the jugular venous pressure waveform exceeds a predetermined threshold value.

2. The device of claim 1, wherein the rotation sensor is configured to measure the angular velocity of the rotation sensor, and the processing system is configured to calculate the time integral of the angular velocity, the angular velocity of the rotation sensor representing the measurement signal, and the time integral of the angular velocity indicating the jugular venous pressure waveform.

3. The device of claim 1, wherein the rotation sensor is configured to measure the angular acceleration of the rotation sensor, and the processing system is configured to calculate a first time integral and a second time integral, the first time integral being the time integral of the angular acceleration and the second time integral being the time integral of the first time integral, the angular acceleration of the rotation sensor representing the measurement signal, and the second time integral indicating the jugular venous pressure waveform.

4. The device of any one of claims 1 to 3, wherein the processing system is configured to receive one or more electrical signals from electrodes on the skin of the individual, and the processing system is configured to generate an electrocardiogram for a time interval of the jugular venous pressure waveform.

5. The device of any one of claims 1 to 3, wherein the processing system and the rotation sensor are configured to maintain a wireless link to transmit the measurement signal from the rotation sensor to the processing system.

6. The device as described in any of claims 1 to 3, wherein the rotation sensor is part of a mobile phone.

7. The device of any one of claims 1 to 3, wherein the device comprises a flexible material sheet (308) having an adhesive to attach the rotation sensor (302) to the individual’s skin.

8. A method for measuring a jugular venous pressure waveform, the method comprising: generating (401) a measurement signal by means of a rotation sensor abutting against a skin of an individual and in a motion sensing relationship with a jugular vein of the individual; and generating (402) a waveform of a movement of the skin in a direction perpendicular to the skin based on the measurement signal indicating rotation of the rotation sensor, the waveform of the movement of the skin indicating the jugular venous pressure waveform, wherein the method comprises calculating an angular displacement (φ) of the rotation sensor based on the measurement signal, wherein the angular displacement represents the waveform of the movement of the skin in the direction perpendicular to the skin, characterized in that the method comprises generating an indicator signal expressing pulmonary hypertension in response to a condition in which an a-wave of the jugular venous pressure waveform exceeds a predetermined threshold value.

9. The method of claim 8, wherein the rotation sensor measures the angular velocity of the rotation sensor, and the method includes calculating a time integral of the angular velocity, the angular velocity of the rotation sensor representing the measurement signal, and the time integral of the angular velocity indicating the jugular venous pressure waveform.

10. The method of claim 8, wherein the rotation sensor measures the angular acceleration of the rotation sensor, and the method includes calculating a first time integral and a second time integral, the first time integral being the time integral of the angular acceleration and the second time integral being the time integral of the first time integral, the angular acceleration of the rotation sensor representing the measurement signal, and the second time integral indicating the jugular venous pressure waveform.

11. The method of any one of claims 8 to 10, wherein the method comprises receiving one or more electrical signals from electrodes on the individual's skin and generating an electrocardiogram for a time interval of the jugular venous pressure waveform.

12. The method of any one of claims 8 to 10, wherein the measurement signal is received from the rotation sensor via a wireless link.

13. Use of an apparatus as claimed in any one of claims 1 to 7 for measuring a jugular vein pressure waveform.

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