Wearable imaging photoplethysmography devices and methods

Abstract

A wearable imaging photoplethysmography monitor employing a frame, a light source, a light detector and a controller. In operation, the light source (32, 132) illuminates an imaging photoplethysmography of an ophthalmic cavity of the patient when the frame is worn by the patient and when the light source (32, 132) is in optical communication with a head orifice of the patient. The light detector detects a photoplethysmogram of the ophthalmic cavity of the patient when the light source (32, 132) is illuminating an imaging photoplethysmography of an ophthalmic cavity of the patient and when the light detector (33, 133) is in optical communication with an eye cavity of the patient. The controller (34, 134) deriving photoplethysmography parameter(s) of the ophthalmic cavity of the patient (e.g., cerebral blood flow) from the detecting of the photoplethysmogram of the ophthalmic cavity of the patient by the light detector (33, 133).

Description

[0001] WEARABLE IMAGING PHOTOPLETHYSMOGRAPHY DEVICES AND METHODS

[0002] FIELD OF THE INVENTION

[0003] The present disclosure generally relates to photoplethysmography. The present disclosure particularly relates to utilizing photoplethysmography for determining an efficiency of cardiopulmonary resuscitation.

[0004] BACKGROUND OF THE INVENTION

[0005] Cardiopulmonary resuscitation (CPR) is intended to be a lifesaving intervention that is provided when a patient is in cardiac arrest, i.e., with no or ineffective mechanical activity of the heart, and providing chest compressions during CPR is a critical aspect of CPR. The aim of the chest compressions is primarily to compress the left ventricle of the heart so that blood is forced the systemic circulatory circuit to thereby provide blood supply to the brain to avoid neurological damage and / or death and to provide blood supply to the heart to prevent damage to the heart. This provides the CPR responder / team with time to triage the cause of cardiac arrest and take effective action.

[0006] A challenge with providing chest compressions is that there is no feedback on the efficacy of the same. Typically, manual palpation is used in between series of chest compressions to assess the presence of a spontaneous cardiac pulse to determine whether return of spontaneous circulation (ROSC) has occurred, but this is difficult to perform and has poor sensitivity.

[0007] More particularly, during CPR, there are two aspects which a CPR responder / team wants to assess.

[0008] The first aspect is an assessment of the efficacy of the chest compressions. Specifically, during chest compressions, a CPR responder / team would like to obtain feedback on the quality of the chest compressions, such as, for example, receiving feedback on the rate at which chest compressions are being delivered to thereby ascertain determine whether chest compressions are being delivered consistently in accordance with CPR guidelines (e.g., a rate of 100 min'1).

[0009] The second aspect is the assessment of the spontaneous activity of the heart, as the goal of CPR is to “restart” the heart. A prerequisite for spontaneous mechanical cardiac activity is organized electrical cardiac activity, i.e., an organized spontaneous electrocardiogram (ECG) rhythm, which is therefore assessed first. Then, if the ECG rhythm is organized (i.e., no asystole, no ventricular fibrillation (VF) and no ventricular tachycardia (VT)), the CPR responder / team can assess the spontaneous mechanical cardiac activity, which is currently often done by performing manual palpation when there are no chest compressions.

[0010] However, manual palpation is challenging and time-consuming, leading to long interruptions in the chest compressions which adversely affects CPR outcome. Alternatively, the CPR responder / team may assess presence of a spontaneous pulse via an arterial line, which is more reliable, but this is an invasive procedure and cumbersome during CPR.

[0011] Moreover, an electrocardiogram (ECG) is routinely measured during CPR. However, measuring the electrical activity of the heart through ECG is not adequate to assess presence of a spontaneous pulse, because this assesses the spontaneous electrical activity of the heart only and not the mechanical activity of the heart, i.e., ECG does not assess the cardiac-induced blood flow through contractions of the heart.

[0012] Conventional contact photoplethysmography (PPG) (e.g. a finger pulse oximeter probe) can be used to obtain information about presence of a spontaneous cardiac pulse, but this approach does not provide information about the status of the blood flow to the brain.

[0013] SUMMARY OF THE INVENTION

[0014] The present disclosure is directed to an imaging photoplethysmography (PPG) of an ophthalmic cavity of a patient, which may be correlated with cerebral blood flow of the patient.

[0015] The present disclosure may be embodied as (1) a wearable imaging PPG monitor and, (2) an imaging photoplethysmography method executable by the wearable imaging PPD device.

[0016] Various exemplary embodiments of a wearable imaging PPG monitor of the present disclosure employs a light source, a light detector and a controller that may be, individually or collectively, integrated into a frame wearable on a head of the patient (e.g., an eyewear frame or a mouthpiece frame). The light source (e.g., one or more light emitting diodes) is configured to illuminate an imaging photoplethysmography of an ophthalmic cavity of the patient when the frame is worn by the patient and when the light source is in optical communication with a head orifice of the patient (e.g., via a waveguide connected to the light source and inserted within the head orifice of the patient). The light detector (e.g., a photodetector, an array of photodetectors or a camera) is configured to detect a photo-plethysmogram of the ophthalmic cavity of the patient when the light source is illuminating an imaging photoplethysmography of an ophthalmic cavity of the patient and when the light detector is in optical communication with an eye cavity of the patient. The controller is configured to derive photoplethysmography parameter(s) of the ophthalmic cavity of the patient (e.g., cerebral blood flow) from the detecting of the photo- plethysmogram of the ophthalmic cavity of the patient by the light detector.

[0017] Various exemplary embodiments of an imaging photoplethysmography method of the present disclosure are executable by a wearable imaging photoplethysmography monitor of the present disclosure. The method involves (1) illuminating, by the light source, an image photoplethysmography of an ophthalmic cavity of the patient when the frame is worn by the patient and when the light source is in optical communication with a head orifice of the patient; (2) detecting, by the light detector, a photo-plethysmogram of the ophthalmic cavity of the patient when the light source is illuminating an imaging photoplethysmography of an ophthalmic cavity of the patient and when the light detector is in optical communication with an eye cavity of the patient; and (3) deriving, by the controller, photoplethysmography parameter(s) of the ophthalmic cavity of the patient from the detecting of the photo-plethysmogram of the ophthalmic cavity of the patient by the light detector.

[0018] The foregoing exemplary embodiments and other embodiments of the present disclosure as well as various structures and advantages of the present disclosure will become further apparent to those having ordinary skill in the art from the following detailed description of various embodiments of the present disclosure read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the present disclosure rather than limiting, the scope of the present disclosure being defined by the appended claims and equivalents thereof.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present disclosure will present in detail the following description of exemplary embodiments with reference to the following figures wherein:

[0021] FIG. 1 illustrates a flowchart representative of an exemplary embodiment of an imaging photoplethysmography method in accordance with the present disclosure; FIGS. 2A-2D illustrates exemplary illuminations of the ophthalmic cavity via a nose orifice, a mouth orifice, an ear orifice and an eye orifice in accordance with the present disclosure;

[0022] FIG. 3 illustrates an exemplary general embodiment of a wearable imaging photoplethysmography eyewear in accordance with the present disclosure;

[0023] FIGS. 4A-4D illustrates exemplary illuminations of the ophthalmic cavity by imaging photoplethysmography eyewear of FIG. 3 in accordance with the present disclosure;

[0024] FIGS. 5A and 5B illustrate exemplary specific embodiments of the imaging photoplethysmography eyewear of FIG. 3 in accordance with the present disclosure;

[0025] FIGS. 6A-6C illustrate exemplary specific embodiments of eyewear frames of FIGS. 5 A and 5B in accordance with the present disclosure; and

[0026] FIG. 7 illustrates an exemplary general embodiment of a wearable imaging photoplethysmography mouthpiece in accordance with the present disclosure;

[0027] FIGS. 8A-8D illustrates exemplary illuminations of the ophthalmic cavity by imaging photoplethysmography mouthpiece of FIG. 7 in accordance with the present disclosure; and

[0028] FIG. 9 illustrates an exemplary embodiment of a controller in accordance with the present disclosure.

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] The present disclosure is directed to detecting a return of spontaneous circulation (ROSC) during CPR, and especially spontaneous circulation to the brain. To this end, the present disclosure utilizes the principle of photoplethysmography (PPG) to assess perfusion and blood volume variation (a derivative of flow) in the brain.

[0031] Specifically, a photoplethysmography (PPG) signal, called photo-plethysmogram, is an optically obtained plethysmogram that can be used to detect pulsatile blood volume changes in the microvascular bed of tissue. A photo-plethysmogram is often obtained by using a pulse oximeter which illuminates the skin and measures pulsatility of transmitted intensity caused by pulsatile changes in total light absorption. A conventional pulse oximeter monitors blood volume variations and pulsations in the dermis and subcutaneous tissue of the skin. Typically, these sensors are placed on the fingers, toes, earlobes and forehead and sometimes the on alar wing or ear concha. These methods are not optimal for CPR. Specifically, the goal of CPR is to obtain return of spontaneous circulation (ROSC) and especially spontaneous circulation to the brain and the aforementioned methods do not detect presence of a spontaneous cardiac pulse in the arterial supply to the brain. Therefore, the present disclosure is directed to utilizing the principle of PPG to assess perfusion and blood volume variation (a derivative of flow) in the brain.

[0032] The present disclosure acknowledges brain arteries can be optically accessed via the ophthalmic cavity, and the present disclosure is based on a discovery that the eye is a “window” to the brain for detecting reflected light in the head, particularly the ophthalmic cavity. The signal strength of the light emitted into the head should be relatively low, for which reason amount of surface area that is sensorized must be increased, for instance, by using a 2D grid of photodetectors. For this, the present disclosure exposes cavities in the head with a light source. This can be obtained by illumination of the ear orifice or the oro-nasal orifice. The light that is used can pass through the eye orifice. Light will be inserted into one or more head orifices, reflected in all the connected cavities and after its interaction with large areas of tissue with blood vessels, emitted via the eye orifices.

[0033] Pulse oximeters typically use red and near IR (nIR) light, because both wavelengths penetrate well through tissue (centimeters). In practice, if the blood is highly oxygenated, the red light will likely penetrate deeper because of its low absorption (e.g. at 660 nm). However, as the oxygenation drops due to insufficient circulation, it is possible that the nIR wavelength becomes advantageous in terms of penetration depth in the tissue. Therefore, in practice, a light source of the present disclosure will be emit red and / or near IR light.

[0034] The key aspects of the present disclosure are (1) illuminating an image photoplethysmography of an ophthalmic cavity of the patient when a frame is worn by the patient and when the light source is in optical communication with a head orifice of the patient; (2) detecting a photo-plethysmogram of the ophthalmic cavity of the patient when the light source is illuminating an imaging photoplethysmography of an ophthalmic cavity of the patient and when the light detector is in optical communication with an eye cavity of the patient, and (3) deriving photoplethysmography parameter(s) of the ophthalmic cavity of the patient from the detecting of the photo-plethysmogram of the ophthalmic cavity of the patient by the light detector. To facilitate an understanding of the present disclosure, the following description of FIG. 1-6 teaches in accordance with the present disclosure for making and using various embodiments of the present disclosure. From the following description of FIGS. 1-6, those having ordinary skill in the art of the present disclosure will appreciate how to apply the present disclosure to make and use additional embodiments of the present disclosure.

[0035] Referring to FIG. 1, a flowchart 10 is representative of a cerebral blood detection method of the present disclosure. Referring to FIG. 1, a stage S12 encompasses an illumination of an image photoplethysmography of ophthalmic cavity via head orifices, and a stage S14 encompasses a detection a photo-plethysmogram of the ophthalmic cavity of the patient from one or more the eyes.

[0036] In one exemplary embodiment as shown in FIG. 2A, a PPG light emission 21 is emitted through one or more of the nostrils and a PPG light detection 20, as reflected throughout the head, particularly the ophthalmic cavity, is from one or more the eyes.

[0037] In a second exemplary embodiment as shown in FIG. 2B, a PPG light emission 22 is emitted through the mouth and the PPG light detection 20, as reflected throughout the head, particularly the ophthalmic cavity, is from one or more the eyes.

[0038] In a third exemplary embodiment as shown in FIG. 2C, a PPG light emission 23 is emitted through the ear and the PPG light detection 20, as reflected throughout the head, particularly the ophthalmic cavity, is from one or more the eyes.

[0039] In a fourth exemplary embodiment as shown in FIG. 2C, a PPG light emission 23 is emitted through the ear and the PPG light detection 20, as reflected throughout the head, particularly the ophthalmic cavity, is from one or more the eyes.

[0040] Referring back to FIG. 1, a stage S16 of flowchart 100 encompasses deriving PPG parameters (and CPR parameters) from the detected photo-plethysmogram.

[0041] In practice, the imaging PPG signals collected from the ophthalmic cavities are analyzed to assess presence / absence of a spontaneous cardiac pulse in the arterial blood supply to the brain, to determine the spontaneous cardiac pulse rate and to determine the rate at which the chest compressions are being delivered. This information can be determined from the imaging PPG signals via e.g. spectral analysis, as known in the art of the present disclosure. The delivered chest compressions will result in a harmonic series in the imaging PPG signals. When the heart resumes beating, this will result in a second harmonic series being present in the imaging PPG signals during chest compressions. Both harmonic series can be individually identified based on the number of harmonic components present in the series and the amplitude relationship between the components of the harmonic series. For each of these series a specific number of harmonics is expected, e.g., three for the harmonic series corresponding to the spontaneous cardiac pulse and five or more for the harmonic series corresponding to the chest compressions. For each of these series a specific relationship is expected for the amplitudes of the harmonic components, e.g., the harmonic components corresponding to the spontaneous cardiac pulse are expected to decay fast in amplitude over the harmonics, while the harmonic components corresponding to the chest compressions are expected to decay slowly in amplitude over the harmonics. If a harmonic series corresponding to a spontaneous cardiac component is detected in the imaging PPG signal, this indicates presence of a spontaneous cardiac pulse in the arterial supply to the brain and its fundamental component provides the spontaneous cardiac pulse rate which both can be reported to the clinical team to provide information about the condition of the patient. If a harmonic series corresponding to chest compressions is detected in the imaging PPG signal, its fundamental component provides the chest compression rate which can be reported to the clinical team to provide information about the adequacy of the rate of the delivered chest compressions.

[0042] Furthermore, in pauses in chest compressions, e.g. occurring for ventilations, the timetrace of the imaging PPG signal can be directly analyzed for presence of a periodic signal. If a periodic signal is detected during pauses in chest compressions, this indicates presence of a spontaneous cardiac pulse in the arterial supply to the brain and the periodicity provides information about the spontaneous cardiac pulse rate, both of which can be reported to the clinical team to provide information about the condition of the patient.

[0043] The present disclosure provides a wearable device like wraparound glasses which are embedded with photodetectors that will capture light via, or in, the ophthalmic cavity.

[0044] Referring to FIG. 3, an exemplary embodiment of a wearable device 30 of the present disclosure employing an eyewear 31, a light source 32 (e.g., a LED), a light detector 33 (e.g., a photodetector or photodetector array), signal / display controllers 34, display(s) 35 and one or more accessories 36. In practice, light source 32, light detector 33, controllers 34, display 35 and one more accessories 36 are integrated into eyewear 31 by an manner that facilitates the principles of the present invention as shown in FIGS. 4A-4D.

[0045] In one exemplary embodiment as shown in FIG. 4A, light source 32 (not shown) is integrated with a temple of device 30 and in optical communication with the nose of the patient via a light guide 40a. Light detector 33 (not shown) is integrated with the eyewear frame of device 30 and detects light reflected through the patient and emitted by the eyes.

[0046] In a second exemplary embodiment as shown in FIG. 4B, light source 32 (not shown) is integrated with a temple of device 30 and in optical communication with a mouth of the patient via a light guide 40b. Light detector 33 (not shown) is integrated with the eyewear frame of device 30 and detects light reflected through the patient and emitted by the eyes.

[0047] In a third exemplary embodiment as shown in FIG. 4C, light source 32 (not shown) is integrated with a temple of device 30 and in optical communication with an ear of the patient via a light guide 40c. Light detector 33 (not shown) is integrated with the eyewear frame of device 30 and detects light reflected through the patient and emitted by the eyes.

[0048] In a fourth exemplary embodiment as shown in FIG. 4D, light source 32 (not shown) is integrated with a temple of device 30 and in optical communication with one of the eyes of the patient. Light detector 33 (not shown) is integrated with the eyewear frame of device 30 and detects light reflected through the patient and emitted by the other eye of the patient.

[0049] FIG. 5 A illustrates one exemplary embodiment of an eyewear frame 37 coupled to a pair of temples 38(1) and 38(2) as known in the art of the present disclosure. Light source 32 is embedded in left temple 38(2) and monitor 34 is embedded in right temple 38(1). A pair of light detectors 33(1) and 33(2) are mounted on a patient side of eyewear frame 37 as best shown in FIG. 6A, and parameter display 35a and a waveform display 35b are mounted on a responder side of eyewear frame 37 as best shown in FIG. 6C.

[0050] FIG. 5B illustrates a second exemplary embodiment of an eyewear frame 37 coupled to a pair of temples 38(1) and 38(2) as known in the art of the present disclosure. Monitor 34 is embedded in right temple 38(1). Light source 32 and light detector 33 are mounted on a patient side of eyewear frame 37 as best shown in FIG. 6A, and display(s) 35(1) and 35(2) are mounted on a responder side of eyewear frame 37 as best shown in FIG. 6C. Referring back to o FIG. 3, as related to accessories 36, the device can contain an accelerometer to measure compression-induced motion of the glasses and assess the chest compression rate from the accelerometer signals. Obtaining information about the chest compression rate facilitates to discriminate between the compression-induced frequency components and spontaneous cardiac-induced frequency components in the PPG signal once the heart resumes beating, which helps to provide feedback about the spontaneous cardiac activity. Alternatively, the device can obtain the chest compression rate information via a (wireless) communication link with a monitor-defibrillator which is enabled to provide feedback about the delivered chest compressions.

[0051] Furthermore, in order to allow the caregivers to still look at the patients’ eyes to assess how they are recovering, the eyewear can be designed to have sufficient distance to the eyes such that the caregivers can still look at the patients’ eyes underneath. Alternatively, the display part can be moved to a location covering the forehead. Alternatively, the glasses can contain a mirror at the top and / or bottom of the glasses which allows a view at the eyes. Alternatively, a camera can be included in the glasses to show a view of the patients’ eyes on the screen.

[0052] During CPR, ventilation can be performed using a ventilation mask. Therefore, the design of the glasses will accommodate sufficient space around the nose such that a ventilation mask can be properly placed. For instance, the device can be designed to not be supported on the nose bridge, but to be supported by the eyebrow region. This ventilation mask or endotracheal tube can also be used to include the light source as both have good access to the mouth cavity of the patient.

[0053] EEG electrodes may be integrated in the device as clinicians are interested in the cerebral electrical activity. More particularly, electrodes are also placed on the skin of the forehead and alternatively the device can accommodate for a traditional EEG lead set to be connected.

[0054] Furthermore, the CMUT US transducers may be integrated in the device. A single (or 2) transducer(s) can be operated in CW7PW mode to receive a doppler signal of the brain vessels near the skull. These signals would be a measure for flow to the brain and can be used together with the PPG signal to better predict the CPR performance. In practice, a wearable device 130 may be positioned on a head of a patient by any manner as known in the art of the present disclosure and hereinafter conceived that is not harmful to the patient, yet allows the functionality of the present disclosure to be achieved.

[0055] For example, referring to FIG. 7, an exemplary embodiment of a wearable device 130 of the present disclosure employing a mouthpiece 131, a light source 132 (e.g., a LED), a light detector 133 (e.g., camera), si gnal / di splay controllers 134, display(s) 135 and one or more accessories 136.

[0056] In practice, light source 132, light detector 133, controllers 134, display 135 and one more accessories 136 are integrated into mouthpiece 131 by an manner that facilitates the principles of the present invention as shown in FIGS. 8A-8D. Alternatively for display 135, the light detector 133 as a camera may include a display on the rear side of the camera.

[0057] In one exemplary embodiment as shown in FIG. 8 A, light source 132 integrated with a mouthpiece frame 131a of device 130 and in optical communication with the nose of the patient via a light guide 80a. Light detector 133 (not shown) is integrated with a camera mount 13 lb of device 130 and detects light reflected through the patient and emitted by the eyes.

[0058] In a second exemplary embodiment as shown in FIG. 8B, light source 132 (not shown) is integrated with a mouthpiece frame 131a of device 130 and in optical communication with a mouth of the patient via a light guide 80b. Light detector 133 (not shown) is integrated with the camera mount 13 lb of device 130 and detects light reflected through the patient and emitted by the eyes.

[0059] In a third exemplary embodiment as shown in FIG. 8C, light source 132 (not shown) is integrated with a mouthpiece frame 13 la of device 130 and in optical communication with an ear of the patient via a light guide 80c. Light detector 133 (not shown) is integrated with the camera mount 13 lb of device 130 and detects light reflected through the patient and emitted by the eyes.

[0060] In a fourth exemplary embodiment as shown in FIG. 8D, light source 132 (not shown) and light detector 133 (not shown) are integrated with the camera mount 131b of device 130 whereby light source 132 emits PPG in one eye of the patient and light detector 133 detects light reflected through the patient and emitted by the other eye of the patient. Wearable device 130 operates under the same aforementioned principles of wearable device 30 to achieve an acquisition of PPG parameters helpful to a revival of a patient, particularly during CPR.

[0061] Referring to FIG. 9, shown is an exemplary embodiment of controller 50 that includes one or more processor(s) 51, memory 52, a user interface 53, a network interface 54, and a storage 55 interconnected via one or more system bus(es) 56.

[0062] Each processor 51 can be any hardware device, as known in the art of the present disclosure or hereinafter conceived, capable of executing instructions stored in memory 52 or storage or otherwise processing data. In a non-limiting example, the processor(s) 51 can include a microprocessor, field programmable gate array (FPGA), application-specific integrated circuit (ASIC), or other similar devices.

[0063] The memory 52 can include various memories, as known in the art of the present disclosure or hereinafter conceived, including, but not limited to, LI, L2, or L3 cache or system memory. In a non-limiting example, the memory 52 can include static random access memory (SRAM), dynamic RAM (DRAM), flash memory, read only memory (ROM), or other similar memory devices.

[0064] The user interface 53 can include one or more devices, as known in the art of the present disclosure or hereinafter conceived, for enabling communication with a user such as an administrator. In a non-limiting example, the user interface can include a command line interface or graphical user interface that can be presented to a remote terminal via the network interface 54.

[0065] The network interface 54 can include one or more devices, as known in the art of the present disclosure or hereinafter conceived, for enabling communication other components of a medical device. In a non-limiting example, the network interface 54 can include a network interface card (NIC) configured to communicate according to the Ethernet protocol. Additionally, the network interface 54 may implement a TCP / IP stack for communication according to the TCP / IP protocols. Various alternative or additional hardware or configurations for the network interface 54 will be apparent.

[0066] The storage 55 can include one or more machine-readable storage media, as known in the art of the present disclosure or hereinafter conceived, including, but not limited to, read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices, or similar storage media. In various non-limiting embodiments, the storage 55 can store instructions for execution by the processor(s) 51 or data upon with the processor(s) 51 may operate. For example, the storage 55 may store a base operating system for controlling various basic operations of the hardware.

[0067] The storage 55 can also store an application modules in the form of executable software / firmware for implementing the various functions of the method of FIG. 7 as previously described in the present disclosure.

[0068] In one exemplary embodiment as shown, storage 55 stores application modules 57 including an ultrasound imaging module 58 to implement stage SI 02 of flowchart 100 of FIG. 7 and a heart compression manager 59 to implement stages S104-S110 of FIG. 7. From the description of FIGS. 1-6 herein, those having ordinary skill in the art will appreciate the numerous benefits of the present disclosure including, but not limited to, (1) a reduced motion artefact benefit achieved by illumination of a relatively large tissue surface whereby the motion artefacts caused by the resuscitation can be smaller than in the case of illumination via a small point (like in a conventional probe). The relatively large illumination surface also allows to inject relatively large amounts of light in a safe manner because the light picks up PPG modulation from a larger tissue volume than the more superficial conventional probes, and (2) there is an SNR benefit. With transmission through the mentioned cavities and connecting channels, in accordance with the present disclosure, the light picks up PPG modulation from a larger tissue volume than the more superficial conventional probes. Moreover, the longer the light path through tissue, the stronger the PPG modulation, since it is a cumulative effect. These two benefits are illustrated in the below figures.

[0069] The present disclosure has been described with reference to the preferred embodiments. Modifications and alterations may occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

[0070] Further, as one having ordinary skill in the art shall appreciate in view of the teachings provided herein, features, elements, components, etc. disclosed and described in the present disclosure / specification and / or depicted in the appended Figures and / or recited in the Claims can be implemented in various combinations of hardware and software, and provide functions which may be combined in a single element or multiple elements. For example, the functions of the various features, elements, components, etc. shown / illustrated / depicted in the Figures and / or recited in the Claims can be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions can be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which can be shared and / or multiplexed. Moreover, explicit use of the term “processor” or “controller” should not be construed to refer exclusively to hardware capable of executing software, and can implicitly include, without limitation, digital signal processor (“DSP”) hardware, memory (e.g., read only memory (“ROM”) for storing software, random access memory (“RAM”), non-volatile storage, etc.) and virtually any means and / or machine (including hardware, software, firmware, combinations thereof, etc.) which is capable of (and / or configurable) to perform and / or control a process.

[0071] Moreover, all statements herein reciting principles, aspects, and exemplary embodiments of the present disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (e.g., any elements developed that can perform the same or substantially similar functionality, regardless of structure). Thus, for example, it will be appreciated by one having ordinary skill in the art in view of the teachings provided herein that any block diagrams presented herein can represent conceptual views of illustrative system components and / or circuitry embodying the principles of the invention. Similarly, one having ordinary skill in the art should appreciate in view of the teachings provided herein that any flow charts, flow diagrams and the like can represent various processes which can be substantially represented in computer readable storage media and so executed by a computer, processor or other device with processing capabilities, whether or not such computer or processor is explicitly shown.

[0072] Having described preferred and exemplary embodiments of the present disclosure, which embodiments are intended to be illustrative and not limiting, it is noted that modifications and variations can be made by persons having ordinary skill in the art in view of the teachings provided herein, including the appended Figures and claims. It is therefore to be understood that changes can be made in / to the preferred and exemplary embodiments of the present disclosure which are within the scope of the present disclosure and exemplary embodiments disclosed, described and taught herein.

[0073] Moreover, it is contemplated that corresponding and / or related systems incorporating and / or implementing the device or such as may be used / implemented in a device in accordance with the present disclosure are also contemplated and considered to be within the scope of the present disclosure. Further, corresponding and / or related method for manufacturing and / or using a device and / or system in accordance with the present disclosure are also contemplated and considered to be within the scope of the present disclosure.

Claims

Claims1. A wearable imaging photoplethysmography monitor (30, 130), comprising: a frame (31, 131) configured to be worn on a head of a patient; a light source (32, 132) integrated with the frame (31, 131), wherein the light source (32, 132) is configured to illuminate an imaging photoplethysmography of an ophthalmic cavity of the patient when the frame (31, 131) is worn on the head of the patient and when the light source (32, 132) is in optical communication with a head orifice of the patient; a light detector (33, 133) configured to detect a photopl ethy smogram of the ophthalmic cavity of the patient when the light source (32, 132) is illuminating an imaging photoplethysmography of the ophthalmic cavity of the patient and when the light detector (33, 133) is in optical communication with an eye cavity of the patient; and a controller (34, 134) configured to derive at least one photoplethysmography parameter of the ophthalmic cavity of the patient from a detection of the photoplethysmogram of the ophthalmic cavity of the patient by the light detector (33, 133).

2. The wearable imaging photoplethysmography monitor (30, 130) of claim 1, wherein the frame is one of an eyewear frame or a mouthpiece frame.

3. The wearable imaging photoplethysmography monitor (30, 130) of claim 1, wherein the light source (32, 132) includes at least one light emitting diode.

4. The wearable imaging photoplethysmography monitor (30, 130) of claim 1, further comprising: a waveguide connected to the light source and insertable within the head orifice of the patient to facilitate the optical communication between the light source and the head orifice of the patient.

5. The wearable imaging photoplethysmography monitor (30, 130) of claim 1, wherein the light detector (33, 133) includes at least one of a photodetector array or a camera.

6. The wearable imaging photoplethysmography monitor (30, 130) of claim 1, wherein the photoplethysmography parameter of the ophthalmic cavity of the patient includes a cerebral blood flow of the patient.

7. The wearable imaging photoplethysmography monitor (30, 130) of claim 1, wherein the controller (34, 134) further configured to derive at least one cardiopulmonary resuscitation parameter from the at least one photoplethysmography parameter of the ophthalmic cavity of the patient.

8. The wearable imaging photoplethysmography monitor (30, 130) of claim 1, wherein the at least cardiopulmonary resuscitation parameter includes a cardiac compression rate.

9. The wearable imaging photoplethysmography monitor (30, 130) of claim 1, wherein the light detector (33, 133) is integrated with the frame.

10. The wearable imaging photoplethysmography monitor (30, 130) of claim 1, wherein the controller (33, 133) is integrated with the frame.

11. An imaging photoplethysmography monitoring method of a patient executable by a wearable imaging photoplethysmography monitor including a frame, a light source, a light detector and a controller, the cerebral blood flow monitoring method comprising: illuminating, by the light source (32, 132), an image photoplethysmography of an ophthalmic cavity of the patient when the frame is worn by the patient and when the light source (32, 132) is in optical communication with a head orifice of the patient; detecting, by the light detector (33, 133), a photopl ethy smogram of the ophthalmic cavity of the patient when the light source (32, 132) is illuminating an imaging photoplethysmographyof an ophthalmic cavity of the patient and when the light detector (33, 133) is in optical communication with an eye cavity of the patient; and deriving, by the controller (34, 134), at least one photoplethysmography parameter of the ophthalmic cavity of the patient from the detecting of the photoplethysmogram of the ophthalmic cavity of the patient by the light detector (33, 133).

12. The photoplethysmography monitoring method of claim 11, further comprising: inserting an optical waveguide connected to the light source into the head orifice of the patient to facilitate the optical communication between the light source and the head orifice of the patient.

13. The photoplethysmography monitoring method of claim 11, wherein the photoplethysmography parameter of the ophthalmic cavity of the patient includes a cerebral blood flow of the patient.

14. The photoplethysmography monitoring method of claim 11, further comprising: deriving, by the controller (34, 134), at least one cardiopulmonary resuscitation parameter from the at least one photoplethysmography parameter of the ophthalmic cavity of the patient.

15. The photoplethysmography monitoring method of claim 11, wherein the at least cardiopulmonary resuscitation parameter includes a cardiac compression rate.

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