Opto-mechanical method for arterial pulse measurement and cardiopulmonary hemodynamic assessment

Abstract

Provided herein is an optomechanical sensing system. The system can include a surface displacement system worn by a patient, including a deformable surface configured to be positioned against the patient and proximate to a superficial artery thereof, a plurality of optical markers disposed on the deformable surface, and an actuator configured to apply pressure to seat the surface displacement system against the patient such that spatiotemporal movement of the superficial artery causes corresponding movement of the deformable surface and the plurality of optical markers. The system further includes an optical system including an imaging system, a light source, and with or without a mirror, configured to visualize the plurality of optical markers at an oblique angle. The system determines spatiotemporal movement of the superficial artery based on the received plurality of images, and determines a cardiopulmonary parameter associated with the patient based thereon.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 063,482, filed August 10, 2020, entitled “Optical Method for Arterial Pulse Measurement,” the entire contents of which are incorporated herein by reference. Background Technology

[0003] It is well known that the measurement of cardiopulmonary parameters (such as heart rate (HR), blood pressure (BP), respiratory rate (RR), and respiratory pattern) and other hemodynamic parameters (such as cardiac output, stroke volume, and peripheral vascular resistance) is important for human health. The ability to identify abnormal blood pressure patterns, such as white coat hypertension, masked hypertension, and non-dipper and other abnormal patterns during sleep and morning blood pressure spikes, is particularly important. The ability to accurately measure cardiopulmonary parameters in a non-invasive, dynamic manner is beneficial for hospitals in the accurate assessment and treatment of critically ill patients. Such accurate measurements allow physicians and other healthcare professionals to better tailor treatment plans and / or identify lifestyle factors to manage hypertension and other chronic conditions that benefit from strict blood pressure control, such as heart failure, sleep apnea, and chronic renal failure. Traditional blood pressure and hemodynamic monitoring devices suffer from accuracy issues, cannot provide long-term dynamic results, or are relatively invasive; all of these factors significantly limit their application scenarios. Therefore, a system suitable for long-term, non-invasive, dynamic monitoring of patients' hemodynamic parameters would be highly advantageous. Summary of the Invention

[0004] This article generally describes systems and methods for noninvasive assessment and continuous monitoring of cardiopulmonary parameters, particularly by directly measuring displacement on the skin surface and forces on superficial arteries (e.g., the radial artery at the wrist).

[0005] In one embodiment, this document provides an optomechanical sensing system for a patient, comprising: a surface displacement system worn by the patient, the surface displacement system including: a deformable surface configured to abut against the patient and adjacent to a superficial artery; a plurality of optical markers disposed on the deformable surface; an actuator configured to apply pressure to abut the surface displacement system against the patient, such that spatiotemporal movement of the superficial artery causes corresponding movement of the deformable surface and the plurality of optical markers; an imaging system configured to visualize the plurality of optical markers at a tilt angle; and a computer system coupled to the imaging system, the computer system including a processor and a memory storing instructions that, when executed by the processor, cause the computer system to: receive a plurality of images of the plurality of optical markers from the imaging system; determine the spatiotemporal movement of the optical markers based on the received plurality of images; and determine cardiopulmonary parameters associated with the patient based on the determined spatiotemporal movement of the optical markers.

[0006] In another embodiment, this document provides a method for monitoring cardiopulmonary parameters of a patient using a surface displacement system, wherein the measuring device includes a deformable surface, a plurality of optical markers disposed on the deformable surface, and an actuator configured to apply pressure to bring the surface displacement system against the patient. The method includes: fixing the surface displacement system near a superficial artery of the patient; applying pressure to the actuator to bring the surface displacement system against the patient, such that spatiotemporal movement of the superficial artery causes corresponding movement of the deformable surface and the plurality of optical markers; capturing a plurality of images of the plurality of optical markers via an imaging system oriented at an angle tilted relative to the optical markers; determining the spatiotemporal movement of the optical markers via a computer system based on the received plurality of images; and determining cardiopulmonary parameters associated with the patient via the computer system based on the determined spatiotemporal movement of the optical markers.

[0007] In yet another embodiment, this document provides an optomechanical sensing system for a patient and an imaging system, comprising: a surface displacement system worn by the patient, the surface displacement system including: a deformable surface configured to abut against the patient and adjacent to a superficial artery; a plurality of optical markers disposed on the deformable surface, wherein the plurality of optical markers are configured to be visualized by the imaging system at an angle; an actuator configured to apply pressure to abut the surface displacement system against the patient, such that spatiotemporal movement of the superficial artery causes corresponding movement of the deformable surface and the plurality of optical markers; and a computer system coupled to the imaging system, the computer system including a processor and a memory storing instructions that, when executed by the processor, cause the computer system to: receive a plurality of images of the plurality of optical markers from the imaging system; determine the spatiotemporal movement of the optical markers based on the received plurality of images; and determine cardiopulmonary parameters associated with the patient based on the determined spatiotemporal movement of the optical markers. Attached Figure Description

[0008] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the invention and, together with this document, serve to explain the principles, features, and characteristics of the invention. In the drawings:

[0009] Figure 1A This is a block diagram of a non-invasive hemodynamic parameter monitoring system according to embodiments disclosed herein.

[0010] Figure 1B This is another block diagram of a non-invasive hemodynamic parameter monitoring system according to embodiments disclosed herein.

[0011] Figure 2 This is a first embodiment of a non-invasive hemodynamic parameter monitoring system using a deformable gel elastomer, according to the embodiments disclosed herein.

[0012] Figure 3 This is a second embodiment of a non-invasive hemodynamic parameter monitoring system using a deformable gel elastomer, according to the embodiments disclosed herein.

[0013] Figure 4 This is a first embodiment of a non-invasive hemodynamic parameter monitoring system using deformable surfaces, according to the embodiments disclosed herein.

[0014] Figure 5 This is a second embodiment of a non-invasive hemodynamic parameter monitoring system using deformable surfaces, according to the embodiments disclosed herein.

[0015] Figure 6AThis is a second embodiment of a non-invasive hemodynamic parameter monitoring system using a piston, according to the embodiments disclosed herein.

[0016] Figure 6B This is a second embodiment of a non-invasive hemodynamic parameter monitoring system using an auxiliary inflatable bag, according to the embodiments disclosed herein.

[0017] Figure 7A This is a perspective view of a measuring device according to an embodiment disclosed herein.

[0018] Figure 7B yes Figure 7A A reverse perspective view of a measuring device according to an embodiment disclosed herein.

[0019] Figure 8A This is a perspective view of a personally worn measuring device according to an embodiment disclosed herein.

[0020] Figure 8B yes Figure 8A A reverse perspective view of a personal wearable measuring device according to an embodiment disclosed herein.

[0021] Figure 9 It is a coordinate system defined relative to the deformable surface according to the embodiments disclosed herein.

[0022] Figure 10A Based on the embodiments disclosed herein Figure 2 and Figure 3 The time diagram of the measurement embodiment shown.

[0023] Figure 10B Based on the embodiments disclosed herein Figure 4 and Figure 5 The time diagram of the measurement embodiment shown.

[0024] Figure 11A Based on the embodiments disclosed herein Figure 2 and Figure 3 The illustrated measurement device shows schematic displacement signals at multiple locations in an embodiment of the device.

[0025] Figure 11B Based on the embodiments disclosed herein Figure 4 and Figure 5 The illustrated measurement device shows schematic displacement signals at multiple locations in an embodiment of the device.

[0026] Figure 12A Based on the embodiments disclosed herein Figure 2 and Figure 3 Surface diagrams of the maximum optical marker displacement at multiple locations in an embodiment of the measuring device shown.

[0027] Figure 12BBased on the embodiments disclosed herein Figure 4 and Figure 5 Surface diagrams of the maximum optical marker displacement at multiple locations in an embodiment of the measuring device shown.

[0028] Detailed description

[0029] This article describes a system and method for optically measuring skin surface movement by placing an array of optomechanical sensors and applying counterpressure to the skin over a large superficial artery (e.g., the radial artery at the wrist) to noninvasively assess arterial pulse and its characteristics. This information can be used to generate continuous arterial pulse waveforms and measure blood pressure (BP), heart rate (HR), respiratory rate (RR), and other hemodynamic parameters. The intra-arterial pressure wave is directly related to the force and displacement on the inner surface of the arterial wall, which in turn affects the deformation and stress on the overlying skin surface (particularly in specific locations, such as the region above a superficial artery, like the radial artery).

[0030] Optical methods can accurately measure the pulse and characteristics of large blood vessels. Compared to optical plethysmography (PPG), a commonly used optical measurement method for heart rate monitoring, this optical method is more reliable for measuring heart rate. PPG uses a light source and a photodetector to measure the volume changes of blood circulation in capillaries on the skin surface. Compared to the optical method described in this paper, PPG signal intensity is weaker and is affected by factors such as motion artifacts and ambient temperature.

[0031] In this optical method, since skin movement is observed above the radial artery during arterial pulsation, the characteristics of the spatiotemporal pattern can be altered by changing the external back pressure applied to the skin above the artery. Features such as the shape, size, and displacement of the spatiotemporal pattern will vary depending on the applied back pressure and intravascular pressure. By analyzing the spatiotemporal pattern, blood pressure (BP) can be continuously measured, as described in our previous PCT patent application publication WO 2019 / 195120A1 entitled "Tactile Blood Pressure Imaging Device," filed March 29, 2019, the entire contents of which are incorporated herein by reference.

[0032] During arterial pulsation, the movement of the skin above the radial artery is primarily in a direction perpendicular to the skin surface, also known as the z-axis. The system and method described in this paper aim to measure the movement of the skin surface above the radial artery.

[0033] Non-invasive hemodynamic parameter monitoring

[0034] The system and method described herein aim to ensure a tight bond between the deformable surface with optically marked features and the patient's skin by non-invasively abutting soft tissue to place an optically marked pattern on the surface of a piece of skin connected to an artery and applying a controlled amount of pressure. The optically marked features can be dots, lines, stripes, grids, or any other pattern. Once fixed in place, changes in arterial geometry and force can be detected during the cardiac cycle based on the perturbation or movement of the optically marked features caused by the mechanical pulsation of the artery. These changes correspond to spatiotemporal signals from the artery or adjacent soft tissue. These spatiotemporal signals can be measured and processed by a computer system or controller to determine hemodynamic parameters.

[0035] Figure 1A An embodiment of an optomechanical sensing system 100 according to embodiments disclosed herein is illustrated. The optomechanical sensing system 100 may include an optical system 102 configured to visualize or otherwise monitor a patient device. In some embodiments, the optical system 102 may be configured to be detached around the patient's wrist, such that only the patient device or a portion thereof (e.g., surface displacement system 108) rests against the skin of the patient's radial artery, particularly near the wrist. For example, the surface displacement system 108 may image via a mobile phone optical system completely detached from the patient's body or an optical system attached to a fixed surface (e.g., a physical wall) or another part of the body (e.g., a shoulder). The surface displacement system 108 may include one or more optical markers 106 positioned on or otherwise associated with a deformable surface 109. The deformable surface 109 may be made of a variety of materials, such as thermoplastic polyurethane or nylon. The thickness of the deformable surface 109 may be, for example, from 10 μm to 300 μm.

[0036] Figure 1BAn optomechanical sensing system 100 according to an embodiment disclosed herein is illustrated. The optomechanical sensing system 100 may include an optical system 102, which includes an imaging system 104 and a light source 112. In some embodiments further described below, the optical system 102 may include one or more mirrors 131 and a transparent or clear layer (e.g., a transparent plate 122, as described below), through which the imaging system 104 is configured to visualize the surface displacement system 108. In some embodiments, the optical system 102 may be configured to be mounted to or attached around a patient's wrist such that a portion of the optical system 102 rests against the surface displacement system 108 on the patient's skin adjacent to the radial artery (particularly at the wrist). The surface displacement system 108 may include a deformable surface 109 having optical markings 106. The optical markings may be dots, lines, stripes, grids, or any other pattern. In various embodiments, the deformable surface 109 may include a membrane, an elastomer, an air-filled or fluid-filled sac, or any combination of these options. As described above, the deformable surface 108 may be made of a variety of materials, such as thermoplastic polyurethane or nylon. The thickness of the deformable surface 108 can be, for example, from 10 μm to 300 μm.

[0037] The surface displacement system 108 can be configured to deform, move, or otherwise change in response to mechanical pulsation through the patient's radial artery, thereby causing a corresponding movement of the optical marker 106. The movement of the optical marker 106 can be visualized via the imaging system 104. The optomechanical sensing system 100 may also include a computer system 114 coupled to the optical system 104. The computer system 114 may be programmed or otherwise configured to calculate one or more cardiopulmonary parameters associated with the patient based on the detected movement of the optical marker 106 visualized via the optical system 104. In some embodiments, the optical system 102 may also include a light source 112, which can be configured to illuminate the optical marker 106 with electromagnetic radiation (EMR) in the visible light or an invisible portion of the spectrum (e.g., infrared or ultraviolet). In some embodiments, the light source 112 may also be used to project the optical marker onto the deformable surface 109.

[0038] The optomechanical sensing system 100 may also include an actuator 110 configured to apply force to the skin above a major artery (e.g., the radial artery at the wrist) via the surface displacement system 108 to aid in the visualization of arterial pulsation. In particular, if the interface between the surface displacement system 108 and the skin is not tightly coupled, it may negatively affect the ability of the surface displacement system 108 to deform due to the patient's arterial pulsation, thereby affecting the ability of the optomechanical system 100 to detect and calculate the patient's cardiopulmonary parameters. The actuator 110 may include a bounded space, such as a balloon or chamber, which may be inflated by an air pump or motorized piston. In some embodiments, the actuator 110 may include manually adjustable components, such as a manual strap. In another embodiment, the actuator 110 may include electromechanically adjustable components, such as a motor configured to tighten a strap, balloon, cuff, pouch, or other components configured to apply pressure to the patient.

[0039] Computer system 114 may include hardware, software, firmware, or a combination thereof, programmed or otherwise configured to cause computer system 114 to perform the actions described herein. In the illustrated embodiment, computer system 114 may also include processor 116 and memory 118 coupled thereto. Memory 118 may store instructions that, when executed by processor 116, cause computer system 114 to receive images of optical marker 106 from imaging system 104; determine the spatiotemporal movement of superficial arteries (e.g., radial artery) based on the received multiple images; and determine cardiopulmonary parameters accordingly. For example, computer system 114 may reconstruct the arterial pulse and measure blood pressure (BP) based on respiratory changes in BP. As another example, computer system 114 may measure respiratory rate (RR) and respiratory pattern, and measure cardiac output, stroke volume, and other cardiopulmonary parameters based on analysis of BP waveforms. In one embodiment, computer system 114 may be incorporated into or otherwise integrated into other components of a patient-worn device, imaging system 104, or optomechanical sensing system 100. In another embodiment, computer system 114 may be communicatively coupled to a patient-worn device, imaging system 104, or other components of optomechanical sensing system 100. For example, computer system 114 may be embodied in a cloud computing architecture.

[0040] In various embodiments, the optical system 104 may include a single camera (or image sensor) or multiple cameras (or image sensors) that can be configured to provide stereoscopic visualization of the optical marker 106. In some embodiments, the optical system 102 may be positioned above the actuator 110 (e.g., Figures 2 to 4 (as shown in the embodiment) or below the actuator 110 (e.g. Figure 6B (The illustrated embodiment). In other embodiments, the optical system 10 may be located inside the actuator 110 or otherwise integrated into the actuator 110, for example... Figure 5The embodiments shown are illustrated. In any of these embodiments, the imaging system 104 may be positioned at an angle relative to the surface displacement system 108, thereby increasing the sensitivity of surface displacement detection (Z-movement) and improving the visualization of the optical marker 106, which will be described in more detail below.

[0041] In various embodiments, the optical marker 106 may include a variety of different colors or patterns that are visually recognizable by the imaging system 104. Furthermore, in various embodiments, the optical marker 106 may be configured to reflect or emit EMR in the visible portion of the EMR spectrum; however, the optical marker 106 may also be configured to reflect or emit EMR in other portions of the EMR spectrum, such as infrared (IR) or ultraviolet (UV) light. Therefore, the imaging system 104 may be configured to utilize a variety of different imaging modalities and include corresponding components. For example, the optical marker 106 may include IR markers and the imaging system 104 may include an IR camera or image sensor. As another example, the pattern of the optical marker 106 on the deformable surface 109 may include a series of black markers on a white background, white markers on a black background, or any other group of colors that provides a distinguishable pattern.

[0042] One problem that must be overcome is that the illumination light produces visible artifacts, such as unwanted reflections and scattering, which degrade the image quality of the optical marker 106 captured by the imaging system 104 and used to measure the patient's arterial pulsation. To reduce the visibility of such artifacts, in one embodiment of the optomechanical sensing system 100, the optical marker 106 may include a fluorescent pigment and be illuminated with short-wavelength EMR, such as blue, violet, or ultraviolet light. For example, the surface displacement system 108 may include a black deformable surface 109 covered with fluorescent yellow dots as optical markers 106, which is configured to be illuminated by short-wavelength light. The yellow pattern information will be visible in the red and green channels of a color camera, while blue or violet light will be visible in the blue channel. If UV light is used, and the imaging system 104 is not sensitive to UV light, then UV light will be invisible to the imaging system 104.

[0043] In another embodiment, the imaging system 104 may include a monochrome camera and the optical marker 106 may include a fluorescent pattern. For example, if the excitation source is blue light and the fluorescence of the optical marker 106 is yellow, the blue light can be blocked by placing a yellow filter on the lens of the monochrome camera, thereby ensuring that only the yellow pattern of the optical marker 106 is visible. The same principle would apply to the excitation / fluorescence optical marker 106 pair, where the excitation wavelength and emission wavelength can be separated by using a color filter.

[0044] Ultraviolet LEDs can be particularly convenient for exciting fluorescence. However, one problem that must be overcome is the "spectral overflow" phenomenon present in most ultraviolet LEDs, meaning that a small portion of visible light is emitted along with the invisible ultraviolet light. To eliminate this spectral overflow, in one embodiment, the light source 112 may include a filter on the LED (e.g., a ZWB1, ZWB2, or ZWB3 glass filter) configured to reduce or remove unwanted visible light, thereby mitigating the spectral overflow of the LED.

[0045] In one embodiment, the deformable surface 109 may include a deformable elastomer gel 120 and a film 130 having optical markers 106, such as Figure 2 As shown. As described above, the patient's wrist 200 includes a radial artery 202, which pulsates during a heartbeat. In the embodiments described herein, this pulsation causes movement of soft tissue and skin above the radial artery 202, thereby causing deformation of a deformable surface 109 comprising a deformable elastomer gel 120 and an optical marker 106 of a membrane 130. In one embodiment, the deformable elastomer gel 120 may be transparent (i.e., translucent or fully transparent). The optical system 102 may also include a transparent plate 122. This plate may be made of polymethyl methacrylate (PMMA) or other such transparent materials. In one embodiment, a surface displacement system 108 may be mounted below the transparent plate 122, such as Figure 2 and Figure 4 As shown, it is configured to come into contact with the patient's skin when worn.

[0046] As described above, the surface displacement system 108 may include an array of patterns, such as dots, grids, stripes, and / or various patterns with lines or other optical markers 106 of various shapes. In use, the optical system 102 is mounted on the radial artery 202 at the patient's wrist, and the strap 126 is attached to the frame 124. The measuring device 102 can be manually pressed against the patient's skin by tightening the strap 126, thereby conforming the surface displacement system 108 to the shape of the wrist, including the skin and tissue above the radial artery 202. Furthermore, the contact force between the surface displacement system 108 and the skin can be adjusted by changing the tightness of the strap 126.

[0047] As described above, the optical system 102 also includes an imaging system 104. In this embodiment, the imaging system 104 can be positioned above the plate 122 such that it is oriented to visualize the optical mark 106 through the plate 122 and the elastomeric gel 120 and to form an image of the optical mark 106. Because the elastomeric gel 120 and the plate 122 are made of transparent materials, the imaging system 104 can thus visualize the optical mark 106 arranged along the membrane 130. Furthermore, the light source 112 can provide illumination to assist the imaging system 104 in visualizing the membrane 130 and the corresponding optical mark 106.

[0048] Therefore, when the patient's heart beats, the radial artery 202 dilates and constricts, causing the optical marker 106 in contact with the skin to move primarily along the z-axis, such as... Figure 2 As shown. As described above, the imaging system 104 can be oriented at an angle (e.g., oblique angle) relative to the optical marker 106. Therefore, the z-axis movement of the optical marker 106 is manifested as a y-axis movement for the imaging system 104, i.e., the optical marker 106 appears to move vertically in the plane of the camera sensor. Based on the measurement of the y-axis movement of the optical marker 106 in the captured image, the computer system 114 can calculate the corresponding z-axis movement of the optical marker 106. Therefore, the spatiotemporal movement of the skin above the radial artery 202 can be determined. By determining the spatiotemporal movement associated with the radial artery 202, various cardiopulmonary parameters can be derived from it. Positioning the imaging system 104 so that it observes the surface displacement system 108 at an angle serves two main purposes. One is to allow for the measurement of z-axis movement, as described above. The other is to allow the device to have a relatively compact form factor, not too bulky, and convenient to wear on the wrist.

[0049] Reference Figure 3 The figure shows another embodiment of the optomechanical sensing system 100 using elastomeric gel 120. However, this embodiment is different from... Figure 2 The difference in the illustrated embodiment is that the actuator 110 is a transparent, inflatable assembly 128 (e.g., a balloon or pouch) located between the elastomeric gel 120 and the plate 122. In this embodiment, the contact force between the surface displacement system 108 and the skin can be adjusted by changing the degree of inflation or air pressure of the inflatable assembly 128 (i.e., the actuator 110) between the plate 122 and the elastomeric gel 120. Figure 2 As in the illustrated embodiment, the surface displacement surface 108 conforms to the shape of the wrist, including the skin and tissue above the radial artery 202.

[0050] In this embodiment, the optical system 102 also includes a mirror system 131 configured to allow the imaging system 104 to indirectly visualize the optical mark 106. In another embodiment, the imaging system 104 may be separate from or directly integrated into the patient-wearing component of the optomechanical sensing system 100. The mirror system 131 may include one or more mirrors configured to provide the imaging system 104 with a view of the optical mark 106 (e.g., at a tilt angle). The optical system 102 may also include one or more lenses 144, such as... Figure 5 As shown in the embodiments.

[0051] In one embodiment, the optomechanical sensing system 100 may include an actuator 110 and a surface displacement system 108, wherein the actuator 110 is an inflatable assembly 128 (e.g., a balloon or bladder), and the surface displacement system 108 is a membrane 130 having optical markers 106, such as... Figure 4 As shown in the figure. This embodiment is similar to... Figure 2 and Figure 3 The illustrated embodiment differs in that the membrane 130 with optical markers 106 is positioned along the inflatable assembly 128 instead of the elastomeric gel 120. The inflatable assembly 128 can be inflated or deflated with fluid (i.e., air) via a pump 142 operably connected to the inflatable assembly 128. The inflatable assembly 128 can be made, for example, of a transparent elastomeric material. In one embodiment, the optomechanical sensing system 100 may further include a pressure sensor configured to monitor the pressure within the inflatable assembly 128 to maintain a desired pressure or pressure range. The transparent plate 122 and frame 124, combined with the strap 126, ensure that the inflatable assembly 128 is held in position against the patient's skin, and it is inflated via a patient-facing surface displacement system 108. In this configuration, the contact force between the surface displacement system 108 and the patient's skin can be varied by changing the tightness of the strap 126 and / or changing the pressure within the inflatable assembly 128. In this embodiment, the imaging system 104 can be positioned to visualize the optical marker 106 through the transparent plate 122 and the transparent inflatable assembly 128 to observe the optical marker 106 on the deformable surface 108. Similar to the previous embodiments, the optomechanical sensing system 100 may also include a light source 112 to provide illumination to aid in the visualization of the optical marker 106. As in the embodiments described above, when a patient's heart beats, the radial artery 202 pulsates, causing movement of the tissue above it. The imaging system 104 can detect the movement of the optical marker 106, and the optomechanical sensing system 100 can accordingly determine the spatiotemporal movement associated with the radial artery 202, thereby deriving various cardiopulmonary parameters associated with the patient.

[0052] refer to Figure 5The figure illustrates another embodiment of the optomechanical sensing system 100 using actuator 110, wherein actuator 110 is a rigid housing 125, with all sides except the skin side covered by a surface displacement system 108, thus allowing contact with the patient. In this embodiment, optical system 102 is positioned within the rigid housing 125. Furthermore, with... Figure 5 Similar to the illustrated embodiment, the optical system 102 also includes a mirror system 131, allowing the imaging system 104 to indirectly visualize the optical marker 106 (e.g., at a tilt angle). In this embodiment, the rigid housing 125 is connected to the pump 142. The surface displacement system 108 can be pressed against the patient's skin by pumping air into and out of the rigid housing 125, thereby conforming the surface displacement system 108 to the shape of the wrist, including the skin and tissue above the radial artery 202. Furthermore, the contact force between the surface displacement system 108 and the skin can be adjusted by changing the tightness of the strap 126.

[0053] Reference Figure 6A The figure illustrates another embodiment of the optomechanical sensing system 100 using piston 160. In this embodiment, the surface displacement system 108 includes a deformable surface, which is an air- or fluid-filled sac 128 positioned above a membrane 130 having optical markers 106. In addition to the transparent plate, this embodiment includes a piston 160 made of a transparent material (e.g., PMMA) configured to move relative to the frame 124 (e.g., vertically). The piston can be made of a rigid transparent material or a soft sac that can be inflated / deflated to function like a piston. Thus, the contact force between the surface displacement system 108 and the patient's skin can be changed by altering the tightness of the strap 126 and by moving the piston 160. In this embodiment, the imaging system 104 can visualize the optical markers 106 through the transparent piston 160. A light source 114 can provide illumination. Similarly, when the heart beats, superficial arteries pulsate, causing movement of the tissue above them, which can be detected by the imaging system 104 based on the movement of the optical markers 106.

[0054] exist Figure 6B In one embodiment shown, the optomechanical sensing system 100 may include an actuator 110, which is an inflatable assembly 128 (e.g., a balloon or pouch) located between the imaging system 114 and the strap 126. The imaging system 114 is in contact with a surface displacement system 108, which is a gel elastomer 120 and a membrane 130 having optical markers 106, such as... Figure 6BAs shown in the diagram. The inflatable assembly 128 can be inflated or deflated with fluid (i.e., air) via a pump 142 operably connected to the inflatable assembly 128. In this embodiment, the inflatable assembly 128 can be made of a durable elastomeric material and does not need to be optically transparent as in the previously described configuration. Some examples of durable materials may include polyvinyl chloride, thermoplastic polyurethane, and neoprene. In one embodiment, the optomechanical sensing system 100 may also include a pressure sensor configured to monitor the pressure within the inflatable assembly 128 to maintain a desired pressure or pressure range. In this setup, the contact force between the surface displacement system 108 and the patient's skin can be altered by changing the tightness of the strap 126 and / or changing the pressure within the inflatable assembly 128. In this embodiment, the imaging system 104 can be positioned to visualize the optical marker 106 through the transparent plate 122 and the transparent gel elastomer 120 to observe the optical marker 106 on the deformable surface 108. Similar to the embodiments described above, the optomechanical sensing system 100 may also include a light source 112 to provide illumination to aid in the visualization of the optical marker 106. As in the embodiments described above, when a patient's heart beats, the radial artery 202 pulsates, causing movement of the tissue above it. The imaging system 104 can detect the movement of the optical marker 106, and the optomechanical sensing system 100 can accordingly determine the spatiotemporal movement associated with the radial artery 202, thereby deriving various cardiopulmonary parameters associated with the patient.

[0055] Figure 2 Figures 6 through 6 illustrate various embodiments of an optomechanical sensing system 100 that uses imaging system 104 to optically measure z-axis movement. In some embodiments, imaging system 104 may include a single camera. In other embodiments, other optical methods, including those using one or more cameras, may be used to measure the z-axis position and movement of optical marker 106. For example, stereo vision, structured light, time-of-flight and other photometric techniques and / or stereo optics techniques may be used to measure the z-axis position and movement of optical marker 106. Many of these methods involve the use of multiple cameras or specialized optical equipment. However, in some embodiments, optomechanical sensing system 100 may advantageously employ optical measurement techniques using only a single camera and requiring little or no specialized equipment, thereby reducing the size, cost, and / or complexity of optomechanical sensing system 100.

[0056] refer to Figures 7A to 8B The figure illustrates an embodiment of an optomechanical sensing system 100, wherein the various components described above, such as the optical system 102, actuator 110, surface displacement system 108, and computer system 114, are included in an exemplary patient-wearing device. In one embodiment, the device may be embodied as a half-bracelet with a hinge 180. Figure 7A This can be used to position the optomechanical sensor 100 using an anatomical reference (e.g., the radial styloid process). The hinge 180 may also have adjustable guides to accommodate various wrist sizes. Positioning is accomplished by sliding the device onto the wrist, where the hinge 180 or some other mechanism (e.g., a linkage, articulated joint, or other adjustable connection) references the radial styloid process to consistently position the device. The hinge 180 can then be adjusted and locked into place according to the wrist size. In this embodiment, the contact pressure applied by the surface displacement system 108 can be adjusted by: (i) compressing the two arms of the bracelet using a motorized system, (ii) adjusting the pressure of the inflatable assembly 128 (as described above, inflating the inflatable assembly 128 increases the tension of the strap 126, thereby increasing the contact pressure), and / or (iii) adjusting the strap 126 (e.g., via a manual system, such as a ratchet dial, or an automatic system, such as a motor that can be used to tighten the strap to apply a contact force by pulling the strap). In various embodiments, the actuator 110 and / or the surface displacement system 108 may be configured such that the contact pressure applied to the skin by the surface displacement system 108 is adjustable between 0 and 350 mmHg.

[0057] In some embodiments, the measuring device 102 may be fluid-sealed. This allows, for example, the measuring device 102 to be worn freely by an individual throughout the day without needing to be removed during certain activities (e.g., showering). Thus, the measuring device 102 can continuously monitor the patient's hemodynamic parameters.

[0058] While the above description relates to the radial artery 202 of the wrist, this description is for illustrative purposes only. It should be understood that the hemodynamic parameter monitoring system 100 can also be used at other locations on the patient's body and / or for other superficial arteries, such as the carotid artery, temporal artery, anterior tibial artery, posterior tibial artery, or brachial artery. Therefore, this disclosure should not be construed as specifically limited to use in conjunction with the patient's wrist and / or radial artery 202.

[0059] Optical Marker Displacement Analysis

[0060] Experimental analysis of various arrangements of the optical marker 106 has identified several different candidate patterns and / or imaging system configurations for use in the optomechanical sensing system 100. Furthermore, the experimental analysis has determined that the movement of the optical marker 106 can be identified with the specificity and accuracy necessary to track the spatiotemporal movement of superficial arteries. Movement analysis of the optical marker 106 can be performed in several different ways. For example, an integral method can be used for movement analysis. In this technique, the cumulative displacement from one frame to the next (i.e., the image captured by the imaging system 104) can be calculated continuously. As another example, a reference method can be used for movement analysis. In this technique, the displacement is calculated relative to a single reference frame. The integral method can provide finer resolution but is also prone to cumulative errors over time. Conversely, the reference method may be affected by constant brightness conditions, which can force it to become unstable under sudden perturbations. Regardless of the movement analysis technique used, the results of the movement analysis can be used to obtain the temporal variance of the target area.

[0061] Experimentally, a coordinate system can be defined relative to the surface displacement system 108, such as... Figure 9 As shown. Furthermore, the distal side 190 and proximal side 192 of the surface displacement system 108 can be defined by their proximity to the imaging system 104. In fact, since the imaging system 104 is oriented at an angle towards the surface displacement system 108, the optical mark 106 will also be more prominent closer to the imaging system 104. The center of the surface displacement system 108 can be defined as the origin. Using the defined coordinate system, Figure 10A The time mask shown is for Figure 2 and Figure 3 The embodiments shown are constructed as follows, Figure 10B The time mask shown is for Figure 4 and Figure 5 The embodiment shown is constructed as described above. The time map is generated by thresholding the variance using a predetermined value. Different masks can be constructed by changing the threshold. The target region can be determined from the map constructed above, and the height map obtained from the initial motion analysis can be filtered to extract data only from the target region. The displacement of the optical marker 106 can then be averaged over the entire target region to obtain a one-dimensional signal that varies over time, describing the average equivalent optical marker displacement in each image frame for a given physical displacement.

[0062] Figure 11A It shows Figure 2 and Figure 3 In the illustrated embodiment, when the surface displacement system 108 displaces over time (x-axis) in the range of 10-100 micrometers, an illustrative displacement signal expressed in pixel units (y-axis) using a simple micrometer is used. Figure 11B It shows Figure 4and Figure 5 In the illustrated embodiment, as the surface displacement system 108 displaces over time (x-axis) in the range of 10-100 micrometers, an illustrative displacement signal is expressed in pixel units (y-axis) using a simple micrometer. These figures illustrate how surface displacement is measured in the optomechanical system 100.

[0063] like Figure 11A and Figure 11B As shown, the displacement of the optical marker 106 can be tracked over time. By tracking the temporal displacement of the optical marker 106 on an image region (e.g., 40mm × 30mm), the temporal displacement of each pixel in a given image can be mapped. Figure 12A and Figure 12B The middle was measured respectively Figure 2 and Figure 3 and Figure 4 and Figure 5 The maximum displacement of the optical marker 106 at a given pixel in the illustrated embodiment depicts a surface displacement map. A surface displacement map can be generated for each pixel at each time point (e.g., 30 milliseconds), providing corresponding high temporal resolution displacement information. This spatiotemporal displacement information can be used to locate and monitor arterial pulsations, thereby monitoring the patient's hemodynamic status. Based on the displacement of the optical marker 106, the high temporal resolution even allows the optical system 102 to identify subpixel movements, which may be crucial for identifying physiologically important parameters, such as dicrotic notches in blood pressure signals.

[0064] While various illustrative embodiments incorporating the principles of this teaching have been disclosed herein, this teaching is not limited to the disclosed embodiments. Rather, this application is intended to cover any variations, uses, or adaptations of this teaching and its general principles. Furthermore, this application is intended to cover deviations from the content disclosed herein that are known or customary practices in the art.

[0065] In the detailed description above, reference has been made to the accompanying drawings, which form a part thereof. In the drawings, similar symbols generally identify similar parts unless the context otherwise requires. The illustrative embodiments described in this disclosure are not intended to be limiting. Other embodiments may be used, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the various features as generally described herein and illustrated in the accompanying drawings can be arranged, replaced, combined, separated, and designed in a variety of different configurations, all of which are expressly contemplated herein.

[0066] This disclosure is not limited to the specific embodiments described herein to illustrate various features. Various modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. In addition to those listed herein, functionally equivalent methods and apparatus within the scope of this disclosure will be apparent to those skilled in the art based on the above description. It should be understood that this disclosure is not limited to specific methods, reagents, compounds, compositions, or biological systems, which can certainly be varied. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0067] Regarding any plural and / or singular terms used herein, those skilled in the art can translate them from plural to singular and / or from singular to plural depending on the context and / or application. For clarity, various singular / plural permutations may be explicitly stated herein.

[0068] Those skilled in the art will understand that, in general, the terms used herein are intended to be “open” terms (e.g., the term “comprising” should be interpreted as “including but not limited to”, the term “having” should be interpreted as “having at least”, the term “including” should be interpreted as “including but not limited to”, etc.). While various compositions, methods, and apparatuses are described as “comprising” various components or steps (interpreted as “including but not limited to”), compositions, methods, and apparatuses may also be “substantially composed of various components and steps” or “composed of various components and steps,” and such terms should be interpreted as essentially defining a closed group of members.

[0069] Furthermore, even when specific numbers are explicitly stated, those skilled in the art should recognize that such statements should be interpreted as indicating at least the stated number (e.g., simply stating "two" without any other modifiers means at least two, or two or more). Additionally, when using conventions such as "at least one of A, B, and C, etc.", generally, this structure is the meaning of the convention that those skilled in the art can understand (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, having only A, having only B, having only C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). When using conventions such as "at least one of A, B, or C, etc.", generally, this structure is the meaning of the convention that those skilled in the art can understand (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, having only A, having only B, having only C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). Those skilled in the art will further understand that any separate words and / or phrases that actually present two or more alternative terms, whether in the specification, exemplary embodiments, or drawings, should be understood to include the possibility of including one, any, or both of the terms. For example, the phrase “A or B” will be understood to include the possibility of including “A” or “B” or “A and B”.

[0070] Furthermore, given that the features disclosed herein are described in accordance with the Markush group, those skilled in the art will recognize that this disclosure is also described in accordance with any individual member of the Markush group or a subgroup of its members.

[0071] As those skilled in the art will understand, for any and all purposes, such as in providing a written description, all scopes disclosed herein also encompass any and all possible subscopes and combinations thereof. Any listed scope can be readily identified as sufficiently descriptive and capable of being decomposed into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each scope discussed herein can be readily decomposed into a lower third, a middle third, and an upper third, etc. As those skilled in the art will also understand, all language such as “at most,” “at least,” etc., includes the listed numbers and refers to a scope that can subsequently be decomposed into subscopes as described above. Finally, as those skilled in the art will understand, a scope includes each individual member. Thus, for example, a group having 1 to 3 units means a group having 1, 2, or 3 units. Similarly, a group having 1 to 5 units means a group having 1, 2, 3, 4, or 5 units, and so on.

[0072] As used herein, the term "about" refers to possible numerical variations, such as those due to real-world measurement or processing procedures; unintentional errors in these procedures; differences in the manufacture, origin, or purity of components or reagents; and so on. Generally, the term "about" as used herein refers to a value or range of values ​​that is greater than or less than 1 / 10 of a specified value, for example, ±10%. The term "about" also refers to variations that are considered equivalent by those skilled in the art, provided that such variations do not include values ​​known in prior art practice. Each value or range of values ​​beginning with the term "about" is also intended to cover embodiments of the absolute value or range of values. Whether or not modified by the term "about," the quantitative values ​​listed in this disclosure include values ​​equivalent to the listed values, such as values ​​that may vary but would be considered equivalent by those skilled in the art.

[0073] The various features and functions disclosed above, as well as other features and functions or alternatives thereof, can be combined into many other different systems or applications. Those skilled in the art can then make various substitutions, modifications, variations, or improvements that are not currently foreseeable or anticipated, each of which is also intended to be included in the embodiments disclosed herein.

[0074] The functions and processing steps described herein may be executed automatically, wholly, or partially in response to user commands. Automatically executed activities (including steps) are performed in response to one or more executable instructions or device operations without requiring direct user initiation.

Claims

1. An optomechanical sensing system for a patient, comprising: A surface displacement system worn by the patient, the surface displacement system comprising: A deformable surface configured to rest against and be adjacent to the patient's superficial artery location. Multiple optical markers are disposed on the deformable surface; An actuator configured to apply pressure to bring the surface displacement system against a patient, such that spatiotemporal movement of the superficial artery causes corresponding movement of the deformable surface and the plurality of optical markers; An imaging system configured to visualize the plurality of optical marks at a tilt angle; A computer system coupled to the imaging system, the computer system including a processor and a memory, the memory storing instructions that, when executed by the processor, cause the computer system to: Receive multiple images of the multiple optical markers from the imaging system. The spatiotemporal movement of the optical marker is determined based on multiple received images, and Based on the spatiotemporal movement of the identified optical markers, cardiopulmonary parameters associated with the patient are determined.

2. The optomechanical sensing system according to claim 1, wherein the deformable surface is selected from elastomeric gels, fluid-filled balloons, membranes, and combinations thereof.

3. The optomechanical sensing system of claim 1, wherein the actuator is selected from pistons configured to move to adjust pressure on the deformable surface, inflatable bladders, adjustable belts, chambers connected to an air pump, and combinations thereof.

4. The optomechanical sensing system according to claim 1, wherein the superficial artery includes the radial artery.

5. The optomechanical sensing system according to claim 1, wherein the cardiopulmonary parameters are selected from heart rate, blood pressure, respiratory rate, and combinations thereof.

6. The optomechanical sensing system according to claim 1, wherein the optical system further comprises: A mirror system configured to enable the imaging system to visualize the plurality of optical marks at the tilt angle.

7. The optomechanical sensing system according to claim 1 further comprises: The housing includes the surface displacement system worn by the patient and the imaging system.

8. The optomechanical sensing system of claim 1, wherein the imaging system is separate from the surface displacement system worn by the patient.

9. The optomechanical sensing system according to claim 1, wherein the plurality of optical marks includes optically visible marks.

10. The optomechanical sensing system of claim 1, wherein the plurality of optical markers includes fluorescent markers.

11. The optomechanical sensing system according to claim 1, further comprising: A transparent layer is located between the imaging system and the plurality of optical markers, wherein the imaging system is configured to make the plurality of optical markers visible through the transparent layer.

12. The optomechanical sensing system according to claim 11, wherein the transparent layer is selected from a transparent plate and a transparent balloon.

13. A method for monitoring cardiopulmonary parameters of a patient using a surface displacement system, wherein the measuring device includes a deformable surface, a plurality of optical markers disposed on the deformable surface, and an actuator configured to apply pressure to bring the surface displacement system against the patient, the method comprising: The surface displacement system was fixed near the patient's superficial arteries; The actuator is pressured to bring the surface displacement system against the patient, causing the spatiotemporal movement of the superficial artery to cause corresponding movement of the deformable surface and the plurality of optical markers; Multiple images of the plurality of optical markers are captured via an imaging system oriented at an angle tilted relative to the optical markers; Based on multiple received images, the spatiotemporal movement of the optical marker is determined via a computer system; Based on the spatiotemporal movement of the determined optical markers, the computer system determines the cardiopulmonary parameters associated with the patient.

14. The method of claim 13, wherein the deformable surface is selected from elastomeric gels, fluid-filled balloons, membranes, and combinations thereof.

15. The method of claim 13, wherein the actuator is selected from a piston configured to move to adjust pressure on the deformable surface, an inflatable bladder, an adjustable belt, a chamber connected to an air pump, and combinations thereof.

16. The method of claim 13, wherein the superficial artery comprises the radial artery.

17. The method of claim 13, wherein the cardiopulmonary parameter is selected from heart rate, blood pressure, respiratory rate, or a combination thereof.

18. An optomechanical sensing system for a patient and an imaging system, comprising: A surface displacement system worn by the patient, the surface displacement system comprising: A deformable surface configured to rest against and be adjacent to the patient's superficial artery location. Multiple optical markers are disposed on the deformable surface, wherein the multiple optical markers are configured to be visualized at an oblique angle by an imaging system; An actuator configured to apply pressure to bring the surface displacement system against a patient, such that spatiotemporal movement of the superficial artery causes corresponding movement of the deformable surface and the plurality of optical markers; A computer system coupled to the imaging system, the computer system including a processor and a memory, the memory storing instructions that, when executed by the processor, cause the computer system to: Receive multiple images of the multiple optical markers from the imaging system. The spatiotemporal movement of the optical marker is determined based on multiple received images, and Based on the spatiotemporal movement of the identified optical markers, cardiopulmonary parameters associated with the patient are determined.

19. The optomechanical sensing system of claim 18, wherein the deformable surface is selected from elastomeric gels, fluid-filled balloons, membranes, and combinations thereof.

20. The optomechanical sensing system of claim 18, wherein the actuator is selected from a piston configured to move to adjust pressure on the deformable surface, an inflatable bladder, an adjustable belt, a chamber connected to an air pump, and combinations thereof.

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