Pulse monitoring device

Abstract

Described herein is a pulse monitor device (1000) including an attachment formation (102) adapted to be removably attachable to a region of a subject's (3000) body. The device (1000) also includes at least one sensor module (202, 204A, 204B) attached to the attachment formation (102)and a processor (502) adapted to detect a pulse signal indicative of a presence or absence of a pulse from the subject (3000). The device (1000) further includes at least one indicator (104) responsive to the pulse signal to provide an indication of the presence or absence of the pulse.

Description

Pulse Monitoring DeviceFIELD OF THE INVENTION

[0001] The present application relates to pulse monitoring devices, and in particular to devices for determining whether an individual requires particular treatment such as cardiopulmonary resuscitation (CPR) or other medical intervention.

[0002] Embodiments of the present invention are particularly adapted for use in a medical emergency such as cardiac arrest and subsequent need for the administration of CPR. However, it will be appreciated that the invention is applicable in broader contexts and other applications.BACKGROUND

[0003] The initiation of effective CPR in cases of sudden cardiac arrest, or the assessment of circulatory status in other non-responsive patients, relies on timely and accurate evaluation of central blood flow. Current standard-of-care assessment protocols, including manual palpation of a central pulse (such as the carotid artery), are highly subjective and prone to inaccuracy, particularly in cases of low blood pressure or other states of impaired perfusion, such as vasoconstriction or low cardiac output. Studies have demonstrated that even trained medical personnel exhibit substantial variability in detecting a pulse by palpation, resulting in potential delays or misjudgements in both initiating and discontinuing CPR. These limitations also extend to periodic reassessment during resuscitation and the identification of return of spontaneous circulation (ROSC), including during in-hospital cardiac arrest scenarios.

[0004] Automated external defibrillators (AEDs) have become widely deployed in public and pre-hospital settings to facilitate early defibrillation. However, such devices generally assess cardiac electrical activity via electrocardiogram (ECG) from surface electrodes and do not confirm whether effective forward flow or central pulsatile arterial blood flow is present. In clinical scenarios such as pulseless electrical activity (PEA), organized electrical activity may be observed in the absence of meaningful mechanical cardiac output. In these cases, reliance on ECG alone can result in inappropriate delays in resuscitation.

[0005] Other devices have attempted to use photoplethysmography (PPG) sensors for the purpose of monitoring pulse in emergency situations. However, PPG sensors rely on eitherreflectance or transmission of light and human tissue provides a high degree of attenuation of light. Depending on the measurement location, this can weaken the signal unacceptably in patients with low perfusion, high fat density, dense hair coverage or darker skin tone. In addition, PPG sensors are prone to motion artifacts and small movements of the patients can strongly affect the reading of the sensor. As such, implementation of PPG sensors has significant drawbacks in this application.

[0006] Various attempts have been made in the art to provide enhanced feedback or monitoring of cardiovascular function during resuscitation. For example:

[0007] US 1 1 ,471 ,375 B2 describes a system for evaluating the quality of OPR based on signals derived from a pulse oximetry sensor. The system processes characteristics such as amplitude and periodicity of the photoplethysmographic waveform to infer whether chest compressions are producing forward flow. However, this system does not provide an assessment of spontaneous circulation prior to or during CPR initiation, and its reliance on peripheral pulse oximetry may limit performance in cases of vasoconstriction or hypoperfusion.

[0008] US 2024 / 0366102 A1 discloses a wrist-worn system configured to detect a loss of pulse using a photoplethysmographic sensor array. The system is designed for continuous wear, is relatively slow to confirm an event, and is not optimised for rapid, point-in-time assessment of circulatory status at specific anatomical sites such as the carotid artery, which are critical during emergency response. Additionally, wrist-based photoplethysmographic sensors are known to be prone to artifacts due to motion and reduced peripheral perfusion.

[0009] US 2022 / 0409070 A1 teaches a capacitive sensor-based apparatus configured to detect arterial wall movement for non-invasive blood pressure monitoring in neonates. While suitable for continuous physiological monitoring, the described system is not optimised for rapid, pointin-time confirmation of pulsatile flow in emergency or triage scenarios. It does not support disposable or fast-deployable configurations intended for quick application nor does it address emergency-specific signal interpretation or anatomical flexibility beyond the intended continuous care setting.

[0010] US 2006 / 0030781 A1 describes a Doppler ultrasound system for detecting arterial blood flow in a portable form. Although highly sensitive, ultrasound-based systems may require careful placement and expertise, limiting their utility in mass-deployment scenarios or by minimally trained users.

[0011] US 2022 / 0087541 A1 discloses a pressure sensor module for wearable applanation tonometry. This disclosure is focused on integration into wrist-worn devices for long-term cardiovascular tracking, and does not address the specific requirements of emergency triage or disposable, neck-mounted implementations.

[0012] US 6,558,321 B1 describes a non-invasive arterial tonometry system configured to capture peripheral pressure waveforms and estimate central blood pressure and pulse wave velocity. While the device is capable of detecting carotid artery pulsations using a pressure sensor applied with calibrated applanation force, its primary use is in cardiovascular diagnostics and research, rather than in emergency response or CPR decision-making contexts. Furthermore, this system is not designed for rapid deployment, nor does it provide immediate actionable feedback for use in pre-hospital triage or public access defibrillation settings.

[0013] While each of the above disclosures contributes to improved cardiovascular monitoring or CPR feedback, there remains an unmet need for a device that provides rapid, reliable, and artefact-resistant detection of central pulsatile blood flow during emergency response. In particular, there is a need for a device that can be applied over the carotid artery to assist a rescuer in determining whether to initiate CPR, and optionally, to monitor whether ongoing compressions are generating effective circulation, or can be terminated due to return of spontaneous contraction.

[0014] In another example, Bravo et al. [Sensors 2021 , 21 , 7549] describe the use of a force sensing resistor (FSR-402) positioned over the radial artery for detecting pulse waveforms. The sensor was secured using a Velcro strap, and the resistance changes due to arterial pulsation were measured and processed to estimate heart rate. While the system demonstrated sensitivity to arterial movement under light contact pressure, it was not designed for application to the carotid artery, nor was it intended for use in emergency or cardiopulmonary resuscitation (CPR) scenarios. The system was implemented at the wrist and focused primarily on general- purpose heart rate monitoring rather than real-time triage or pulse confirmation during cardiac arrest.

[0015] Any discussion of the background art throughout the specification should in no way be considered as an admission that such art is widely known or forms part of common general knowledge in the field.SUMMARY OF THE INVENTION

[0016] Embodiments of the present disclosure seek to address the abovementioned needs through a sensor-equipped device, adapted for rapid application to a region of a patient such as the neck region. The device can detect the presence or absence of central arterial pulsatile activity using one or more modalities, including photoplethysmography, pressure transduction, accelerometry, or other non-invasive methods. The device may optionally include indicators (e.g., visual or auditory) to assist a user in interpreting the detected signal and guiding further action, and may incorporate design features for stable coupling to the skin and minimisation of motion artefact.

[0017] In accordance with embodiments of the present invention, a pulse monitoring device is provided that is adapted for rapid application to the neck or another anatomical site to detect pulsatile blood flow. The device includes one or more sensing modules incorporating photoplethysmographic sensors, pressure-based sensors, and / or motion sensors such as accelerometers. The sensor data is processed in real time to determine whether pulsatile flow is present, providing decision support for use in cardiac arrest or resuscitation scenarios.

[0018] In some embodiments, the processor is configured to filter signal components associated with respiratory movement, swallowing, speaking, or chest compression artefacts. In some embodiments, a pulsatile transducer with known characteristics may be used as a calibration source to improve measurement accuracy. The system may use time-domain and frequency-domain analysis, threshold logic, and correlation between sensor types to enhance signal quality. In some cases, the device may provide a time-bound determination of whether pulsatile flow is present, within a clinically relevant window such as ten seconds.

[0019] In accordance with a first aspect of the present invention, there is provided a pulse monitor device, the device including: an attachment formation adapted to be removably attachable to a region of a subject’s body; at least one sensor module attached to the attachment formation and including a processor adapted to detect a pulse signal indicative of a presence or absence of a pulse of the subject; and at least one indicator responsive to the pulse signal to provide an indication of the presence or absence of the pulse.

[0020] In some embodiments, the region of a subject’s body includes the subject’s neck.

[0021] In some embodiments, the pulse monitor device is adapted to detect a pulse over the subject's thyroid or carotid artery.

[0022] In some embodiments, the at least one indicator includes a visual indicator.

[0023] In some embodiments, the at least one indicator includes an audio indicator.

[0024] In some embodiments, the at least one indicator includes at least one LED.

[0025] In some embodiments, the at least one indicator includes an LCD display.

[0026] In some embodiments, the indicator is adapted to provide audio and / or visual instructions for a person to commence or perform CPR on the subject.

[0027] In some embodiments, the pulse monitor device has at least one sensor module includes a photoplethysmogram (PPG) device.

[0028] In some embodiments, the at least one sensor module includes a piezoelectric device.

[0029] In some embodiments, the at least one sensor module includes a force sensitive resistor.

[0030] In some embodiments, the pulse monitor device has at least one sensor module includes an electrocardiogram (ECG) device.

[0031] In some embodiments, the pulse monitor device has at least one sensor module includes a microphone adapted to detect a pulse from a detected acoustic signal.

[0032] In some embodiments, the at least one sensor module includes a pressure sensor. In one embodiment, the pressure sensor includes a plurality of pistons adapted to detect pulse signals based on changes in fluid or gas (e.g. air) pressure. In another embodiments, the pressure sensor includes a resilient material operably connected to a pressure sensor through which pulse signals are detected. In another embodiment, the pressure sensor includes a plurality of spheres through which a pressure signal is transferred, each sphere being associated with a strain gauge for detecting movements of each sphere in accordance with pressure from a pulse signal.

[0033] In some embodiments, at least one sensor module includes one or more pressure sensing devices, including capacitive sensors, capacitive membranes, interdigitated electrodes(IDEs) or arrays, piezoresistive elements, strain gauges, microfluidic channels, or any other pressure-sensitive structure capable of detecting skin deformation or internal vascular pulsation. A person skilled in the art would appreciate that these sensing modalities may be integrated into flexible, stretchable, or conformable substrates depending on clinical need and site of application.

[0034] In some embodiments, the at least one sensor module includes an array of accelerometers mounted to a flexible surface and adapted to sense a pulse signal on a person’s body.

[0035] In some embodiments, at least one sensor module comprises a spatial array of pressure sensors arranged on a flexible substrate. The distribution of sensing elements allows for spatial coverage across the region of interest and accommodates anatomical variability between patients. The array may support directional flow estimation as a means to enhance robustness to movement artefact, or enable the measurement of pulse wave velocity by analysing relative timing or amplitude differences between adjacent elements. The array may also be configured to increase reliability in cases of imprecise placement. In this regard, the processor may be configured to determine the presence of pulsatile flow by analysing signal features across two or more sensing locations.

[0036] The processor may also be capable of performing pulse wave analysis of detected pressure signals.

[0037] In some embodiments, the sensor module includes at least one sensing element positioned outside the expected arterial region, and wherein the processor is configured to use signals from that element as a control input for undesired artefact suppression or validation of pulsatile flow detection.

[0038] In some embodiments, the sensor module includes at least one transducer that produces a periodic signal of known amplitude and frequency such that the resulting sensor output can be calibrated to account for individual variations in coupling to the person’s body.

[0039] In some embodiments, the sensor module may include at least one transducer capable of producing a pulsatile response of known frequency and amplitude characteristics on the sensor. This response may then be used to calibrate the sensor response for the individual characteristics of each subject.

[0040] In some embodiments, the attachment formation includes an adhesive pad. The adhesive pad may include an acrylic or a silicone adhesive layer. In other embodiments, the adhesive may comprise a hydrogel, a polyurethane-based pressure-sensitive adhesive, a thermoplastic elastomer, or a medical-grade pressure-sensitive material such as polyethylene or ethylene-vinyl acetate. The adhesive is preferably biocompatible and selected for low irritation during short-duration skin contact.

[0041] In some embodiments, the attachment formation may comprise a clamp-like device.

[0042] In some embodiments, the attachment formation may comprise an air pump combined with an adhesive patch to provide positive pressure on the sensor on to the subject.

[0043] In some embodiments, the attachment formation includes a resilient structure adapted to expandably attach to a person’s body.

[0044] In some embodiments, the pulse monitor device includes an accelerometer. In some embodiments, the accelerometer is adapted to generate a signal indicative of non-cardiac motions. These non-cardiac motions may be from the subject or external to the subject.

[0045] In some embodiments, the non-cardiac motions include breathing, swallowing and / or movement of the subject, or motions due to CPR.

[0046] In some embodiments, the processor is adapted to filter the signal indicative of the non-cardiac motions from the pulse signal.

[0047] In some embodiments, the processor is configured to compare time-aligned signals from different sensor modalities, and to confirm a pulsatile event only when a threshold degree of correlation is detected between the modalities.

[0048] In some embodiments, the pulse monitor device includes a body that houses the processor.

[0049] In some embodiments, the pulse monitor device includes an activating tab initially attached to the body and selectively removable to activate an operative state of the pulse monitor device.

[0050] In some embodiments, the activating tab includes visible indicia providing instructions for use of the pulse monitor device.

[0051] In some embodiments, the at least one sensor module includes a plurality of separately disposed sensors.

[0052] In some embodiments, the pulse monitoring device may provide some indicia of CPR quality during CPR.

[0053] In some embodiments, the pulse monitor device includes a pair of sensors disposed about the body, wherein the body is centrally located on the adhesive pad or other attachment formation.

[0054] In some embodiments, the adhesive pad includes a pair of wings that extend from the body around the pair of sensors.

[0055] In some embodiments, the attachment formation may comprise an adhesive pad that includes a peelable protective layer to reveal the adhesive layer.

[0056] In some embodiments, the pulse monitor device includes a data port for communicating data between the processor and an external device.

[0057] In some embodiments, the pulse monitor device includes a wireless device adapted for wireless connectivity for transferring data to and / or from the pulse monitor device.

[0058] In some embodiments, the indicator is adapted to provide audio and / or visual instructions for a person to commence or perform CPR on the subject. In some embodiments, the indicator is adapted to provide audio and / or visual feedback indicating a quality of CPR being performed on the subject.

[0059] In accordance with a second aspect of the present invention, there is provided a pulse monitor device, the device including: an attachment formation adapted to be removably attachable to a region of a subject’s body; at least one sensor attached to the attachment formation, the at least one sensor being adapted to detect a signal indicative of a pulse of the subject; and, in response, generate a sensor signal; a processor, functionally connected to the at least one sensor and configured to process the sensor signal received from the at least one sensor to detect a presence or absence of a pulse of the individual; andat least one indicator, functionally connected to the processor to provide an indication of the presence or absence of the pulse of the individual.

[0060] In some embodiments, the pulse monitor device includes a power source and a card or tab removably attachable to the pulse monitor device and configured to facilitate transfer of power from the power source to the pulse monitor device when the card is detached from the pulse monitor device.

[0061] In some embodiments, the device includes a processing module configured to analyse acquired sensor signals to determine whether the observed pulsatile features are consistent with arterial blood flow. The processor may perform signal conditioning, artefact rejection, and pattern recognition to distinguish pulsatile signals from noise, including respiratory motion, movement artefacts, and external compressions. A decision threshold or confidence metric may be used to generate a pulse-present or pulse-absent output.

[0062] Preferably the region of the individual’s body is the individual’s neck to detect a pulse in the carotid artery.

[0063] In some embodiments, the attachment formation is configured to achieve a desired pressure on the subject's body without manual intervention.

[0064] In some embodiments, the attachment formation is configured to adjust the applied pressure on the subject's body to a desired value iteratively based on the disposed pressure sensor value.

[0065] In accordance with a third aspect of the present invention, there is provided a method of monitoring a pulse of a subject, the method including the steps: receiving, from at least one sensor module attached to the subject, a sensor signal indicative of a pulse of the subject; processing the sensor signal to detect a presence or absence of a pulse of the individual; and controlling an indicator in response to the detection of a presence or absence of a pulse to provide an indication of the presence or absence of the pulse.

[0066] In accordance with a fourth aspect of the present invention, there is provided a pulse monitor device, the device including:an attachment formation adapted to be removably attachable to a region of a subject's body; at least one sensor module attached to the attachment formation and including a processor adapted to detect a pulse signal indicative of cardiac parameters of the subject; and at least one indicator responsive to the pulse signal to provide an indication of the cardiac parameters.

[0067] In some embodiments, the cardiac parameters include one or more of blood pressure, blood flow, heart rate or pulse wave velocity.

[0068] The invention is intended to assist rescuers and clinical personnel in determining whether to initiate or continue cardiopulmonary resuscitation or whether to proceed with application of an automated external defibrillator. The system provides objective, rapid, and portable assessment of central circulation and may be suitable for integration into public access defibrillator kits or other first response equipment.BRIEF DESCRIPTION OF THE FIGURES

[0069] Example embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:Figure 1 shows a front view of a pulse monitoring device in accordance with an embodiment of the invention;Figure 2 shows a further view of the pulse monitoring device;Figure 3 shows the placement of the pulse monitoring device on a person’s neck region;Figure 4 shows a system model of the pulse monitoring device in accordance with an embodiment of the invention;Figure 5 shows a view of an adhesive pad in accordance with an embodiment of the invention;Figure 6 exemplifies a PPG sensor configuration as used in an embodiment of the invention;Figure 7 shows a pressure sensor arrangement in accordance with an embodiment of the invention;Figure 8 shows a further pressure sensor arrangement in accordance with an embodiment of the invention;Figure 9 shows a further pressure sensor arrangement in accordance with an embodiment of the invention;Figure 10 shows a further pressure sensor arrangement in accordance with an embodiment of the invention;Figure 1 1 shows a further sensor arrangement in accordance with an embodiment of the invention which utilises an array of accelerometers;Figure 12 shows a further sensor arrangement in accordance with an embodiment of the invention which utilizes an array of strain gauges;Figure 13 shows an attachment formation and associated lead screw device for the pulse monitoring device in accordance with an embodiment of the present invention;Figure 14 shows an attachment formation in accordance with an embodiment of the present invention;Figure 15 shows an attachment formation in accordance with an embodiment of the present invention;Figure 16 exemplifies an air column housing in accordance with an embodiment of the invention;Figure 17 shows a flow chart exemplifying the use of the pulse monitoring device in accordance with an embodiment of the invention;Figure 18 shows a flowchart in accordance with an embodiment of the invention; andFigure 19 shows a flowchart in accordance with an embodiment of the invention.DESCRIPTION OF THE INVENTION

[0070] Embodiments of the present invention aim to provide a device for simply and quickly providing accurate pulse data from an individual or subject. The device is primarily designed for use on humans. However, it will be appreciated that it may also be suitable for use in the contextof veterinary care / science and more generally on animals. As such, use of the term “subject” encompasses both human and non-human species. It will be appreciated that medical emergencies can and do occur at unexpected times and often when it is difficult to quickly determine if a defibrillator is needed. In such situations, it is critical that devices are made available that can assist both trained medical professionals and those untrained in the medical field to provide much needed assistance in a medical emergency.

[0071] Other embodiments may provide a device for assessing CPR quality whereby, pulse characteristics may be measured prior to the commencement of CPR (as described herein) and during the CPR process to provide an assessment as to the quality of the CPR, or the progress of the CPR.

[0072] The present invention is framed within the context of the Danger, Response, Send for help, Airway, Breathing, CPR, Defibrillation (DRSABCD) action plan which forms the cornerstone of basic and advanced life support. The primary purpose of DRSABCD is to determine quickly and accurately the need for life saving intervention.

[0073] Cardiac arrest can unexpectedly occur, and requires prompt attention and treatment if the individual suffering from such an event is to survive. The evidence shows that, for every minute a person spends in cardiac arrest, their chance of survival decreases by ten per cent. In reference to a chain of survival, early recognition of cardiac arrest is a crucial link to improved outcomes. It is therefore vital that if an individual is suspected of suffering from a cardiac event, such as cardiac arrest, that treatment is administered as soon as possible to improve the chances of survival.

[0074] However, as the standard treatment protocol for cardiac arrest includes the application of a defibrillator such as an AED, it is critical that the individual involved is confirmed as being in a state of cardiac arrest as soon as practically possible. This is due to the fact that in order for an AED to have the greatest chance at saving an individual’s life, it must be applied to the individual as soon as possible. As such, the present invention aims to provide a device for first determining whether an individual is in a state of cardiac arrest or not, so that a lifesaving device such as a defibrillator can be promptly sought and applied to the individual involved.

[0075] Blood pressure is understood to depend on a number of physiological parameters as presented below:BP = CO x SVR.,CO = HR X SV, andSV = EDV - ESV, where BP = blood pressure, CO = cardiac output, SVR = systemic vascular resistance, HR = heart rate, SV = stroke volume, EDV = end diastolic volume, ESV = end systolic volume. The above formulae may be used to determine various physiological parameters including blood pressure based on the combination of inputs above. These relationships also indicate that blood pressure is the most reliable measure of blood supply to vital organs, as it is dependent on the critical independent physiological variables, namely cardiac output and systemic vascular resistance.

[0076] The relationships presented above allow for other aspects of heart physiology to be calculated. For example, by combining multiple sensors and methods, it is possible to determine systemic vascular resistance and other parameters of clinical utility. If the blood pressure, heart rate and systemic vascular resistance are determined, and by estimating the stroke volume, it is possible to determine cardiac output. Similarly, the speed with which the pressure wave generated by the heart's contraction travels through the arteries (pulse wave velocity, PWV) can provide a measure of arterial stiffness. These additional types of information may be used to infer some aspects of the patient’s physiology and provide more information to clinicians in certain settings.

[0077] Embodiments of the present invention aim to detect non-invasive blood pressure at around 60 / 20 mmHg (Sys / Dia) as this is typical for CPR chest compressions (say 30-60 / 10-20 (Sys / Dia)) and be able to distinguish this from very low to zero blood pressure associated with cardiogenic shock (or other shock states) or cardiac arrest. The present invention aims to provide firstly, information regarding the presence or absence of a pulse and secondly, a diagnostic device to determine the presence or absence of a pulse in an individual suffering from a medical emergency so that prompt administration of CPR and subsequent application of a defibrillator can occur.

[0078] Referring initially to Figures 1 to 4, there is illustrated a pulse monitor device 1000 in accordance with an embodiment of the present invention. The pulse monitoring device 1000 includes an attachment formation in the form of an adhesive pad 102 adapted to be removably attachable to a body of subject 3000, such as a neck, as is exemplified in Figure 3. As will be explained below, an adhesive pad represents one of many possible types of attachment formations possible to implement in the present invention.

[0079] The adhesive pad 102 is provided in order to removably attach the pulse monitor device 1000 to the subject 3000, such that an accurate pulse signal can be determined. It will be appreciated that the pulse monitor device 1000 may be removably attached to other areas of the subject’s body such as feet (i.e. the dorsalis pedis artery), wrist, arm, leg, temporal, scalp (fontanelle) or groin (femoral artery) area. These additional various anatomical locations can be used for the purposes of (but not limited to) conducting neurovascular status assessments where perfusion of limbs may require assessment, monitoring a pulse as an ongoing aspect of vital signs assessment, monitoring for absence of blood flow during procedures such as external aortic compression. However, it has been discovered by the inventors of the present invention that the neck region provides a reliable and strong pulse signal typically resulting in a more accurate medical assessment in the setting of an emergency.

[0080] The pulse monitor device 1000 further includes at least one sensor module 202 attached to the adhesive pad 102. The sensor module 202 includes an electronics body 1002 and a pair of sensors 204A and 204B. In other embodiments, sensor module 202 includes a single sensor or more than two sensors disposed at different locations. Example types of sensors are described below.

[0081] Electronics body 1002 houses a processor 502 illustrated in Figure 4) for processing signals derived from the subject’s body. In particular, the processor 502 is adapted to detect or generate a pulse signal (not shown) indicative of a presence or absence of a pulse from the subject 3000. The pulse signal detected by the one or more sensors 204A and 204B is a signal indicative of a pulse of the subject 3000.

[0082] It will be appreciated that the terms sensor module are used herein in a functional sense to refer collectively to the components for sensing a subject’s pulse. These components include the actual sensor devices and associated signal processing elements such as a processor.

[0083] Referring to Figure 4, a system level view of the electronics contained in the body 1002 is shown. The processor 502 is adapted to take signals derived from the sensors 204 for processing. The processor 502 executes code stored in a memory, such as a random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM) or other equivalent memory storage devices as would be apparent to the skilled person.

[0084] In order to provide a means of updating software / firmware in the memory, the pulse monitor device 1000 may include a data port (not shown). The data port is provided for communicating data between the processor and an external device such as a programming terminal. Additionally, the port may be used to provide a means of charging a power source 506 in the form of an internal rechargeable battery 506 contained in the pulse monitor device 1000. In alternative embodiments, the power source 506 may include a replaceable battery (such as a single use battery) which is removable from the body 1002.

[0085] In some embodiments, the pulse monitor device 1000 includes a wireless device adapted for wireless connectivity for transferring data to and / or from the pulse monitor device 1000 to another device. The wireless connectivity may include the use of Bluetooth (IEEE 802.15.1 standard), IEEE802.1 1 ah (Wi-Fi HaLow), BLE, Z-wave or other suitable wireless protocol standards as would be known to the skilled person. The wireless connectivity may facilitate the extraction, or sharing, of stored data from the pulse monitor device 1000, such as a record of the data gathered by the device after use on a subject 3000. The wireless connectivity may also facilitate the monitoring of data being generated by the pulse monitoring device 1000 in real-time or near real-time.

[0086] The pulse monitor device 1000 includes at least one indicator 104 to provide an indication to an operator of the pulse monitoring device 1000 as to whether there is an absence or presence of a pulse in the subject 3000. In the embodiment shown in the figures, the sensor module 202 includes associated electronics to receive a signal or signals from the sensors 204A and 204B and to provide a signal to the indicator 104. In the embodiments shown, two separately disposed sensors are used. Two or more sensors (204A, 204B) can be used to provide a level of redundancy and to improve accuracy by providing two or more signals for correlation, noise filtering and the like. Furthermore, the use of two different types of sensors (204A, 204B) may be used to provide a potentially more reliable reading. The sensors (204A, 204B) may be adapted to measure frequency and amplitude signals. Frequency can be processed to determine heart rate in Beats Per Minute (BPM) of the subject and amplitude can be processed to determine blood pressure, blood flow or cardiac output.

[0087] In some embodiments, both BPM and blood pressure information as well as other physiological parameters such as cardiac output and stroke volume are used for determining the presence or absence of a pulse, as well as understanding the rhythm and quality of that pulse, if required.

[0088] The sensors (204A, 204B) are attachable to the subject 3000 using an adhesive such as a silicone adhesive or acrylic adhesive. The sensors (204A, 204B) may be attached to or embedded into adhesive pad 102 by the use of an adhesive, plastic welding and / or stitched into webbing of pad 102 as some examples.

[0089] The at least one indicator 104 is responsive to the pulse signal and is adapted to provide an indication of the presence or absence of the pulse. In order to determine whether a pulse is present or not, processor 502 performs signal processing on the pulse signal. This may include determining an amplitude and / or frequency of the pulse signal. If the amplitude is above a predefined threshold and / or a frequency within a predefined range of pulse frequencies is detected, processor 502 determines that a pulse is present.

[0090] In some embodiments, the presence or absence of a pulse is determined by the processor 502 based on one or more thresholds of pressure detected by sensors 204A, 204B. In the case of pressure sensors, the thresholds may relate to detected non-invasive blood pressure or mean arterial pressure. By way of example, a threshold of 50 mm Hg for non- invasive blood pressure (NIBP) monitoring or a mean arterial pressure below 40 mm Hg may be used.

[0091] The indicator 104 may take the form of an LED indicator providing an active visual indication or an LCD indicator providing passive (non-light emitting) indication. The LED indicator may comprise a single LED unit providing a single or multiple colour indicators dependent on the signal provided to the LED, or alternatively, and in the embodiment shown in the figures, the indicator 104 may comprise two or more LEDs to provide relevant information to the user. In the embodiment illustrated in Figures 1 and 2, indicator 104 includes a visual display including different coloured LEDs. For instance, a particular colour LED is controlled to be illuminated upon detection of a presence of a pulse while an alternate colour LED is controlled to be illuminated when no pulse is detected.

[0092] Other forms of indicator may include an acoustic indicator to provide an acoustic signal indicating the presence or absence of a pulse. In this regard, the acoustic indicator may comprise a piezo buzzer or an electromagnetic speaker coil for providing an audio signal to the operator of the pulse monitor device 1000. Such indicators would be understood by the skilled person.

[0093] In the embodiments shown in the figures, the adhesive pad 102 takes the form of a pair of wings that extend from the electronics body 1002 around the pair of sensors. The wings preferably extend laterally from either side of the electronics body 1002 to form an elongated symmetric pad. The adhesive pad 102 is formed of a pliable material, allowing for easy application to the subject’s body, and in particular, to their neck region. The wings provide a large surface area for reliable attachment of the pulse monitor device 1000 to a subject 3000. It will be appreciated by a person skilled in the art that the adhesive pad 102 may take a variety of different shapes while still providing the benefit of the invention as will be discussed below. Although only a pair of sensors is shown, it will be appreciated that a greater number of sensors may be included in the device 1000.

[0094] The adhesive pad 102 may be attachable to the electronics body 1002 by way of an adhesive such as silicone or acrylic. In other embodiments, the adhesive pad 102 may be attached to the electronics body 1002 by way of a plastic weld or an attachable clip. In some embodiments, the adhesive pad 102 may be adapted to be replaceable allowing for reuse of the pulse monitor device by replacing the adhesive pads 102. In other embodiments, the pulse monitor device 1000 may be disposable or designed for refurbishment.

[0095] The shape of the adhesive pad 102 is chosen to allow for easy application to a given body part, which in the embodiment shown, includes the neck region. However, the shape of the adhesive pad 102 may necessarily vary depending on which part of the body it is to be applied. For instance, if the adhesive pad 102 is to be applied to the groin area, the symmetric wing structure as is used for the neck region may not be as suitable. In that case, a shape more suitable to the groin region may be chosen.

[0096] In other embodiments, the adhesive pad 102 may be constructed from a material adapted to reduce irritation to the skin of the individual to which the adhesive pad 102 is applied. For instance, hypoallergenic adhesives are known in the art with brands such as 3M producing Micropore ® Adhesive tape which is commonly used in medical applications. Typically, these adhesives are free from latex and other compounds which may provide an allergic reaction to those allergic to latex and similar materials.

[0097] In other embodiments, the pad 102 may take a rectangular or circular form allowing for secure attachment to the leg or neck region of an individual. The adhesive pad 102 may be comprised of an acrylic adhesive for attachment to the individual’s body. Acrylic adhesives provide good tackiness and can be provided in medical grade form.

[0098] Other suitable forms of adhesive for use on the adhesive pad 102 include silicone adhesives. The advantages of silicone adhesives are that they are generally biocompatible resulting in less skin damage than say, the alternative acrylic adhesive which provides better surface adhesion with the disadvantage that it is harder to remove than a silicone adhesive.

[0099] Referring now to Figure 5, the adhesive pad 102 further includes a backing strip 302, which is releasably removable to reveal an adhesive layer of the adhesive pad 102. When in use, the backing strip 302 is removed from the adhesive layer prior to the application to the subject’s body.

[0100] As shown in Figure 5, the backing strip 302 may include visible indicia in the form of instructions for use and other useful information, such as diagrams to an operator of the pulse monitor device 1000. For instance, the backing strip may include a diagram providing a visual representation of the proposed location of the pulse monitoring device on the individual. Other written instructions may also be provided on the backing strip. However, it is preferable that when possible clear visual representations are used as it provides a means of imparting information independent of the language used by the operator.

[0101] The processing performed by processor 502 may include filtering of the signal or signals from the sensors 204A and 204B using digital signal processing techniques, which would be known to a person skilled in the art. The processor 502 may be further adapted to filter one or more signals indicative of the non-cardiac motions of the subject 3000 from the pulse signal. Non-cardiac motions may include actions such as breathing or swallowing, which may detract from or add noise to the pulse signals being acquired. Non-cardiac motions may also include movements being made on the subject 3000 by external influences, such as a person delivering CPR or movements due to vehicle travel, such as an ambulance.

[0102] The sensor module 202 may be adhesively attached to the adhesive pad 102, or in other embodiments may form an integral part of the adhesive pad. In that case, the adhesive pad 102 may be formed with the sensor module 202, as a single unit in the manufacturing process. Alternatively, the sensor module 202 may be plastic welded to the adhesive pad through the application of heat and the use of a suitable thermoplastic amenable to plastic welding.SENSORS

[0103] With reference to the Figures, appropriate sensors in accordance with the present invention will be described below. Preferably, the sensor or sensors are capable of measuring blood pressure, cardiac output, blood flow or a proxy thereof. Blood pressure represents the force of blood pushing on the walls of an artery as the heart pumps blood. The systolic pressure is the pressure in an artery when the heart beats, or contracts, and pumps blood into the arteries. The diastolic pressure is the pressure in an artery when the heart is at rest, between beats, and is filling with blood.

[0104] Blood pressure can be sensed externally by measuring the radial outward pressure on an arterial wall as it expands and contracts. This outward pressure can be sensed by a sensor located on or adjacent the artery such as the carotid artery. This pressure sensing may be performed directly or indirectly. In some embodiments, the sensor(s) are configured and positioned so as to directly measure the pressure exerted radially outwards on an artery as the blood flow changes during the cardiopulmonary cycle. A pulse signal can be derived from the measured pressure over time.

[0105] Referring now to Figure 6, the sensor module 202 may include one or more photoplethysmogram (PPG) sensors 204A and 204B, and more specifically, a reflectance PPG module (R-PPG). R-PPG is similar to PPG sensors with the difference being that rather than measuring transmitted light, R-PPG measures the light reflected from the tissue surface of an individual. As can be seen in Figure 6, each of the R-PPG sensors 204A and 204B includes a light source 602, such as an LED and a photodetector 604. Suitable photodetectors include PN photodiodes and other semiconductor photodetectors which are well known in the art. The PPG sensor module may also include a pressure sensor 605 for determining the applied pressure of the module to a person’s body or as a means of acting as the pressure sensor for the device to measure arterial pulses mechanically and optically in combination Typically, the spacing of the light source 602 from the photodetector 604 has an effect on the performance of the R-PPG detector with ranges of around 2 mm to 6 mm being found to provide signals of good quality and large amplitudes (See page 6 of: M Hickey and P A Kyriacou, Optimal spacing between transmitting and receiving optical fibres in reflectance pulse oximetry, 2007 J. Phys.: Conf. Ser. 85 012030.

[0106] R-PPG measures the light reflected from the tissue 6000 surface and is useful when it is challenging to obtain a good signal through transmission. A typical R-PPG also contains alight source 602 and a photodetector 604. As exemplified in Figure 6, the light source 602 emits light to a tissue and the photodetector 604 measures the reflected light from the tissue 6000. The reflected light is proportional to blood volume variations. R-PPG sensors indirectly measure the heartbeat (and thus pulse rate) providing high accuracy at multiple locations across the body. Other suitable sensors may include piezo electric sensors or ECG (EKG) sensors as other examples each of which would be understood by the skilled person.

[0107] PPG sensors are not capable of directly detecting pressure. However, blood pressure may be indirectly derived from PPG sensor measurements such as by measuring pulse transit time or analysing the morphology of a PPG waveform.

[0108] In other embodiments, the sensor module 202 may include a microphone (not shown) or other acoustic transducer adapted to detect a pulse of an individual via a detected acoustic or pressure signal. This is best described in the research article titled Development of Real- Time Cuffless Blood Pressure Measurement Systems with ECG Electrodes and a Microphone Using Pulse Transit Time (PTT) Jingyu Choi, Younghwan Kang, Jaesoon Park, Yeunho Joung and Chiwan Koo (Sensors 2023, 23, 1684. https: / / doi.org / 10.3390 / s23031684). The subject matter of this document is incorporated herein by way of cross reference. Therein, the use of a microphone in place of a PPG sensor is discussed. The blood pulse wave is measured in the radial artery of the wrist using a microphone that can directly measure the sound generated by a body rather than sending energy inside the body and receiving a returning signal (see ibid. Abstract).

[0109] The microphone (or acoustic sensor) may be used in place of or in addition to other sensors. For example, an acoustic signal derived from a microphone may be used to augment a signal from a PPG or other sensor to derive a more accurate pulse signal.[001 10] Referring now to Figures 7 to 12, there are described various types of pressure sensors for sensing pressure to derive a pulse signal.[001 1 1 ] Pressure sensors in accordance with the present invention may include various transduction mechanisms known in the art. These include, but are not limited to: Capacitive sensors, which detect changes in capacitance caused by mechanical deformation; Strain gauges, using resistive or piezoresistive elements to track surface strain; Force-sensitive resistors (FSRs) with resistive layers; Interdigitated electrode arrays, which measure permittivity or resistance variation across a deformable dielectric; Microfluidic or air-column systems, inwhich pressure changes are relayed via displacement of a medium to a sensing element. In some embodiments, the pressure sensor module comprises a spatial array of sensing elements arranged over a flexible substrate or housing surface. This configuration allows for improved anatomical coverage, accommodating variation in neck size, skin contour, body hair, and placement angle. By distributing sensing points across a broader area, the device increases the likelihood that at least one sensor element is positioned over a major artery such as the carotid. In addition, the system may be configured to compare time-domain or amplitude-domain features across the array to infer the direction and / or velocity of pulse wave propagation. This may enhance robustness to movement artefact and increase reliability when placement precision is suboptimal.[001 12] In some embodiments where mechanical pressure sensors are employed to detect arterial pulsation, it is desirable for the sensor to be coupled to the skin with sufficient force to allow effective transmission of pressure changes from the underlying artery. In such embodiments, the adhesive or attachment formation may be configured to exert a downward force on the skin surface sufficient to locally compress the arterial wall without fully occluding blood flow. This may assist in enabling arterial wall deflection to be transmitted to the pressure sensor, thereby facilitating accurate detection of pulsatile pressure waveforms. The downward force may be applied via an adhesive layer, an overlying housing, a clamping mechanism, or any combination thereof. In some examples, the force applied may be comparable to that used in manual pulse palpation, and may correspond to a local pressure in the range of approximately 10 to 30 mmHg (equivalent to a force of approximately 0.13 to 0.40 N applied over an area of 1 cm2). The adhesive or clamp mechanism may be engineered such that this force is achieved reliably across different user applications while avoiding excessive pressure that may result in arterial occlusion.[001 13] In alternative or additional embodiments, the adhesive or attachment formation may comprise materials selected for their ability to provide controlled force transmission to the sensing element. Suitable materials may include polyisobutylene (PIB)-based pressuresensitive adhesives, bioresorbable or biodegradable adhesives (such as silk fibroin or gelatin), hydrocolloid adhesives, temperature-activated phase-change adhesives, and low-tack adhesives suitable for neonatal or geriatric skin. In some embodiments, the adhesive layer may further comprise a skin-compatible nanofiber, mesh, or scaffold interface configured to distribute pressure evenly and minimise skin irritation. In other embodiments, the adhesive may includeconductive elements configured to transmit electrical signals or serve as part of an electrochemical sensor system. The selection of adhesive materials may be determined according to the intended duration of use, application site, skin type, and the mechanical requirements of the associated sensor module.[001 14] With reference to Figure 7, a sensor in accordance with an embodiment of the present invention is shown. The sensor utilises changes in air, gas or fluid pressure to detect and transmit signals representative of a patient’s pulse signal derived from pressure measurements. As can be seen in Figure 7, the sensor includes an array of pistons 704 provided in a grid like configuration. As will be appreciated by the skilled addressee, the combination of the air column and the array of pistons 704 allows for the pistons 704 of the sensor to conform to the shape / contour of a patient’s body (e.g. neck) due to the compressibility of the air / gas / fluid in the column.[001 15] The use of pressure sensor arrays allows for not only spatial redundancy but also potential estimation of directional blood flow or wave propagation. By analysing the temporal delay and relative amplitude between individual sensor elements across the array, directional flow patterns can be inferred. This provides for a more reliable measurement of pulse that can be independently measured from other motion artefacts.[001 16] The arrangement shown provides desirable contact within the region of interest on the body 706 such as the carotid artery shown as 702. The array of pistons 704 in the sensor exemplified in Figure 7, allows for the sensor to conform to the region on the body to which the sensor is applied 706. Furthermore, by utilising an array of pistons 704, the sensor provides a degree of tolerance insofar as placement of the sensor 700 on the body. For instance, if a single contact point sensor is utilised, the positioning of the sensor on the correct region of the body becomes critical in order to optimally detect a pulse. This is due to the fact that a single contact point would need to be positioned precisely within the vicinity of the region of interest such as above the carotid artery. However, when a plurality of pistons are utilised, the likelihood that at least one of the pistons is located in an optimal location on the body (such as in the region of the carotid artery) to detect a pulse is significantly increased.[001 17] It will be appreciated that the larger the number of pistons which are utilised, the greater the probability that at least some of those pistons are located in an optimal, or at least near optimal location, for detecting blood pressure, blood flow, cardiac output and / or a pulse as an example. It has been discovered by the inventors that the sensitivity of the sensor 700 isdependent on a number of factors such as the diameter of each of the pistons 704, with smaller diameter pistons providing higher sensitivity as compared to larger diameter pistons. Not only do the smaller diameter pistons generally suffer from less inertial effects, due to their lower mass, the smaller surface area of each piston surface allows for the array of pistons to more accurately conform to the shape of the person’s body.[001 18] As shown in Figure 7, each of the pistons 704 is located within a respective cylinder 708 in which the piston 704 moves in accordance with the pulse wave originating from the persons pulse. The cylinders 708 in which the pistons 704 are located, are fluidly connected to an air column region 710, in which the motion of the pistons 704 is detected using an air pressure sensor 712. The air pressure sensor 712 may include a strain gauge or a piezoelectric device as some examples.[001 19] Figure 8 exemplifies another type of a sensor architecture in accordance with an embodiment of the present invention. In this example, rather than transmitting the pulse signal through an air column, the pulse signal is transmitted through a resilient material, which in the embodiment shown is a spring 802, although it may take other forms such as an elastic material or a resilient polymer material as some examples.

[0120] As can be seen in Figure 8, the resilient material 802, in the form of a spring, occupies a space between an end of a moveable piston 804 and a sensing unit 806. The spring 802, piston 804 and sensor 806 are all contained within a housing 810. An array of pistons 804 receive a pulse signal, which may originate from an artery 702, which is then transmitted through the spring 802, which is in contact with the sensor 806. The sensor 806 may take the form of a strain gauge, a force sensitive resistor or a piezoelectric element as some examples. The variations of pressure as derived from the pulse signal, is transmitted through the springs 802 onto the respective sensing units 806. The signal derived from the sensing units 806 may then be sent to a processor (e.g. processor 502 of Figure 4) for processing.

[0121] In yet a further embodiment exemplified in Figure 9, the sensor may include a plurality of pressure sensors, which, in the embodiment shown, take the form of spheres 902 which are adapted to freely move in response to external pressure. As can be seen in Figure 9, each of the spheres sits within a circular strain gauge 904 which is adapted to deform when the spheres 902 experience external forces due to a pressure change such as when a pulse is detected.

[0122] One advantage of the spherical design shown in Figure 9, is the ability to detect forces from multiple directions in contrast to alternative sensors such as flat or rigid sensors which typically detect forces in a unidirectional fashion. As is exemplified in Figure 9, each of the spheres 902 are located within an encasement within which a sensor, in the form of a strain gauge 904 is provided abutting each sphere 902. The skilled person would understand that a variety of different sensors in the form of strain gauges 904 may be utilised including capacitive stain gauges, inductive strain gauges, or piezoelectric strain gauges as some examples. When an external force is applied to any of the spheres 902, such as when the sensor unit is applied near or on an artery, any movement may be detected by the motion of the spheres 902 as they apply a force to the respective strain gauge 904.

[0123] In an exemplary application, the sensor unit is applied to the surface of a person’s body in the vicinity of an artery such as a carotid artery. As the spheres 902 make contact with the skin, the spheres 902 will apply a force on the strain gauge 904 providing a signal at the output of the strain gauge 904 in accordance with the change of pressure at the region in which the specific sphere 902 is being applied.

[0124] Figure 10 shows another sensor architecture providing a means of detecting pressure changes on a person’s body. The sensor includes a plurality of projections 1002 disposed on a flexible surface 1004 which may conform to the shape of a person’s body. As is exemplified in Figure 10, the sensor includes a conductive film layer 1006, adhesive layer 1008 and active electrode layer 1010. The conductive film layer 1006 is placed above the plurality of projections 1002 and is adapted to deform when pressure is applied to the plurality of projections 1002. The sensor operates as follows; when the sensor is placed on a region of the body, such as a neck region, the plurality of projections 1002 transfers mechanical pressure, caused by pulsation pressure as an example, to the conductive film layer 1006. The conductive film layer 1006 then flexes and contacts an active electrode layer, providing an electrical signal that correlates with blood flow dynamics. Like the previously mentioned sensors, the plurality of projections 1002 provide the advantage of increasing the likelihood that at least some of the projections 1002 will be placed in a region of the body that will accurately receive pulse signals from the body.

[0125] Figure 1 1 shows yet another example of a sensor in accordance with the present invention. The sensor shown utilises an array of accelerometers 1 102 which are mounted on a flexible surface 1 104 which is adapted to conform to the shape of a body. As is exemplified inFigure 1 1 , each of the accelerometers 1102 are supported by structures 1 106, which in the embodiment shown, takes a serpentine shape, although other shape configurations may also be suitable, provided they allow for relative movement of the respective accelerometers 1 102. The serpentine shape has been chosen to allow for movement of the accelerometers 1 102 relative to the flexible structure 1 104 which defines an adhesive patch.

[0126] The design aims to ensure that a maximal number of accelerometers 1 102 maintain contact with the skin, while also adapting to contours of the body. Furthermore, the array of accelerometers 1 102 shown, provides the advantage of improving pulse detection accuracy by also providing redundancy through the use of multiple accelerometers 1102. The configuration of multiple accelerometers 1 102 aims to ensure that at least a subset of the accelerometers 1 102 are correctly positioned in relation to the region of interest such as an artery. Each accelerometer 1 102 has the ability to detect micro-movements as a result of pulsatile blood flow. The signals received from the accelerometers 1102 may then be sent to an external device for signal processing. In order to filter out motion artefacts, such as involuntary neck movements (e.g. breathing and swallowing), comparative signal processing may be employed. Some of the accelerometers 1 102 may be placed in non-pulsatile regions of the body while others may be placed in close vicinity to pulsatile regions. The signals derived from non- pulsatile regions and those from pulsatile regions may then be compared using signal processing, allowing for non-pulsatile related motion to be filtered out.

[0127] In embodiments that incorporate multiple sensing modalities, such as optical, mechanical, and inertial sensors, the processor may compare features extracted from each channel to validate the presence of arterial pulsation. For example, periodic waveform features in an accelerometer signal may be temporally aligned with pulsatile peaks in a pressure signal. In cases where correlation is confirmed across sensor types, the output confidence may be increased. Conversely, signals that diverge in timing or shape may be down-weighted or excluded. This fusion of modalities enhances artefact rejection and improves the reliability of the pulse detection decision.

[0128] Furthermore, the accelerometer signals may then be analysed in real-time in order to detect rhythmic pulsations. By identifying frequency and amplitude of the detected movements, carotid pulsations may be differentiated from unwanted noise.

[0129] Figure 12 exemplifies another sensor arrangement in accordance with the present invention. In the sensor arrangement shown in Figure 12, each sensor takes the form of multiplestrain gauges 1202 attached to pads 1204 via elongated structures, such as beams 1206 formed on the internal edges of a frame 1208. In one aspect, the frame 1208 includes thin beams 1208, with each beam 1208 acting as a load-bearing structure.

[0130] The beams 1208 are adapted to deform slightly when placed against a region of the body such as the neck, thus responding to carotid artery movement derived from that region. When the pads 1204 associated with the beams 1206 are placed over an artery or other area of interest, the strain gauges 1202 will undergo a bending displacement where they produce an electrical signal based on the deformation. The electrical signal derived will be representative of a pulse signal. As can be seen in the embodiment shown in Figure 12, the beams 1208 are curved slightly downward to help maintain continuous contact with the skin when the sensor is attached to the body.

[0131] As is best exemplified in Figure 3, the pulse monitor device 1000 is adapted to detect a pulse on the carotid artery which is located in the neck. The carotid artery is found to be a desirable location as it provides a reliable pulse signal, avoiding inaccuracies which can occur when detecting a pulse at other regions of the body.

[0132] In other embodiments, the pulse monitor device 1000 includes an accelerometer or inertial measurement unit (IMU) 504 which is associated with the sensor module 202 and is adapted to measure movement and external forces in the form of acceleration of the device providing additional information to the sensor module 202 for determining the status of the subject 3000. For instance, subtle non-cardiac motions such as swallowing or breathing, and other general movement which may be detected using the accelerometer and filtered out from the pulse readings which may provide more accurate pulse data of the subject 3000. Alternatively or additionally, a microphone may be utilised to detect and cancel signals unrelated to the pulse signals of the individual such as movements caused by a person performing CPR on the individual.

[0133] It will be appreciated that body 1002 is adapted for securely and safely housing the processor 502 and its associated electronics such as the accelerometer 504, the indicator 104 and switching required to turn the pulse monitor device on. In the embodiment shown, the body 1002 takes a rectangular shape with curved sides and edges to avoid sharp points. The shape of the body 1002 will be dictated by a number of factors including the dimensions of the circuit board contained within the body and the electronic components being housed within the body1002. In the embodiments shown, the body 1002 is centrally located on the adhesive pad 102 providing a distributed load on the adhesive pad 102 after application to the individual.

[0134] The body 1002 may be provided with seals to provide water and dust proof capability such as IP67 or IP68 water ingress protection. It may be desirable to provide a level of water ingress protection to prevent moisture from entering the pulse monitor device 1000 with the potential for moisture to induce corrosion and thus the potential electrical malfunction while in operation. As it is of importance that the pulse monitor device 1000 functions reliably in all conditions, waterproofing is an important factor to consider. In this regard, the body may be sealed using rubber or silicone gaskets providing at least a partially watertight seal. In some embodiments, some or all of the materials of device 1000 include UV protection capability.

[0135] As is best exemplified in Figures 1 and 2, the pulse monitor device 1000 may include an activating tab 106, such as a card 106, which is initially attached to the body 1002 and selectively removable from the body 1002 to activate an operative state of the pulse monitor device 1000. This may be achieved by activating an electrical switch upon removal of the activating tab 106.

[0136] The electrical switch is adapted to isolate the power source 506 from the pulse monitor device, by means of a non-conducting material between the live part of the power source 506, such as a battery, and a main supply conductor of the device (not shown).

[0137] The electrical switch (not shown) is housed in the body 1002 and is operably connected to the processor 502, battery 506 and associated circuitry. The switch may include a microswitch, reed switch which may be activated by the motion of a ferromagnetic material embedded in the activating tab 106.

[0138] Similarly to the adhesive backing strip 302, the activating tab 106 may be designed to display instructions and other useful information to a user. Instructions may include directions for pulling the activating tab 106 for turning the pulse monitor device on for use, and other relevant instructions, indicia and / or information pertaining to the correct use of the pulse monitoring device 1000.

[0139] In some embodiments, the device 1000 is adapted to measure other cardiac parameters such as blood pressure, arterial stiffness, blood flow, heart rate or pulse wave velocity. In some embodiments, the device 1000 is adapted to perform pulse wave analysis on received pressure and / or PPG sensor signals. Methods of performing pulse wave analysis canbe found in Parittotokkaporn S, de Castro D, Lowe A, Pylypchuk R. Carotid Pulse Wave Analysis: Future Direction of Hemodynamic and Cardiovascular Risk Assessment. JMA J. 2021 Apr 15;4(2):119-128. doi: 10.31662 / jmaj.2020-0108. Epub 2021 Apr 2. PMID: 33997445; PMCID: PMC81 19021 . The contents of this document are incorporated herein by way of cross reference.Attachment Formation

[0140] With reference to Figures 13a and 13b, a clamp based attachment formation of the pulse monitor device is shown in accordance with the present invention. As can be seen, the pulse monitor device (not shown) may be attached to a region of the body, such as the neck region with the use of a clamp arrangement including two arms 1301 , hingedly attached to each other and including attachment points 1302 which contact the person’s body. The pulse monitoring device 1000 or at least the sensors are disposed on or immediately adjacent to the attachment points 1302 such that they are in close contact to the person’s body when the arms 1301 are in engagement with the person. At the attachment point 1304 which in the embodiment shown, is a hinge, a resilient member such as a spring may be included to provide a clamping force for ensuring the pulse monitor device stays positioned. The clamp based attachment formation provides a scissor like pivoting action which may be actuated using an operators hand, whereby the operator may apply a force to the pivot region to open the clamp structure for positioning on a person’s body.

[0141] As can be seen in Figure 13b, the clamp based attachment formation may also include an adjustment formation utilising a lead screw to dynamically adjust the gripping force as is applied to the person’s body. The lead screw 1308 may be operatively attached to a lead screw motor 1306 that is adapted to dynamically adjust the gripping force applied by the clamp based attachment. The dynamic adjustment of the clamp based attachment aids to ensure that the sensing modules (as were described above in relation to Figures 6 to 12), maintains optimal pressure on the region of a person’s body such as a neck region, without the requirement for manual adjustment. As an example, the baseline pressure to be applied to the sensing module may be used to detect the amount of pressure which is applied by the clamp based attachment to the region of the person’s body. In this case, the clamp based attachment is used to apply or reduce pressure in order to provide optimal pressure to the region.

[0142] Figure 14 shows a further attachment formation in accordance with the present invention. The attachment formation utilises a resilient member 1406 that provides a ridged yetelastic structure for positioning on a person’s body such as their neck region. The advantages of the resilient structure forming the resilient member is that the resilient structure is adapted to expand and contract in accordance with movement of the person’s body. Furthermore, the arrangement may at least partially remove the need for manual adjustments which may be required, and obviates the need for clamps or adhesives.

[0143] Figure 15 shows yet another attachment formation utilising adhesives, a schematic representation of which is shown at 15a. The attachment formation provides a stretchable membrane 150a, adapted to secure the sensing module 152a to a region of interest on the person’s body, which is typically a neck region for the purposes of the present invention. At each end of the adhesive membrane 150a, adhesive attachment points 151 a are located. By utilising the adhesive attachment points 151 a, it is possible to avoid the need for the use of rigid clamps or other mechanical structures. The stretchable membrane 150a secures the sensing module 152a to the person’s body, while the resilient nature of the stretchable membrane allows pressure applied to the sensor 152a to be adjusted by adjusting the tension in the stretchable membrane 150a when it is attached to the person’s body. The stretchable membrane 150a allows an operator to adjust for precise calibration of the baseline force for optimal sensor readings.

[0144] Figure 16 shows a sensor housing utilising dynamic pressure adjustment 1600 using controlled air pressure in accordance with an embodiment of the present invention. The sensor housing of which a cross-section view is shown as 16a includes an air pump 1602 which is fluidly attached to a top portion of a housing 1604. The top portion of the housing 1604 is attached to a housing base 1606 by a stretchable elastomer membrane 1608 which is adapted to expand or contract in accordance with the air pressure applied. The top portion 1604, stretchable elastomer membrane 1608 and housing base 1606 provide an airtight cavity upon which the air pump provides air and associated pressure. The top portion of the housing may also include a housing for electronics for controlling the amount of air provided to the sensor housing. The housing base provides contact with the person's body and includes the sensing module 1603 for detecting a person’s pulse and other vital signs. 16a shows the application of the sensor housing 1600 using an adhesive means, such as an adhesive tape 1610 or gel allowing the air pump to push against the body providing a reaction force.

[0145] In some embodiments where mechanical pressure sensors are employed to detect arterial pulsation, it is desirable for the sensor to be coupled to the skin with sufficient force toallow effective transmission of pressure changes from the underlying artery. In such embodiments, the adhesive or attachment formation may be configured to exert a downward force on the skin surface sufficient to locally compress the arterial wall without fully occluding blood flow. This may assist in enabling arterial wall deflection to be transmitted to the pressure sensor, thereby facilitating accurate detection of pulsatile pressure waveforms. The downward force may be applied via an adhesive layer, an overlying housing, a clamping mechanism, or any combination thereof. In some examples, the force applied may be comparable to that used in manual pulse palpation, and may correspond to a local pressure in the range of approximately 10 to 30 mmHg (equivalent to a force of approximately 0.13 to 0.40 N applied over an area of 1 cm2). The adhesive or clamp mechanism may be engineered such that this force is achieved reliably across different user applications while avoiding excessive pressure that may result in arterial occlusion.Use Case

[0146] As an example of a method of using the pulse monitor device 1000, a typical use scenario is described below.

[0147] In the case where an individual has collapsed and is suspected of suffering from a cardiac event, the pulse monitoring device 1000 would be removed from its storage location and removed from any packaging that may form part of its storage. By reading the instructions provided on both or either the adhesive backing 302 and the activating tab 106, the user will be directed to attach the pulse monitor device to the correct location on the person’s body such as the neck region. If there is significant body hair which may prevent reliable contact with the subject’s skin, this may be trimmed using a pair of scissors or another suitable device, as is commonplace with application of defibrillation pads, to ensure adherence.

[0148] In order to attach the pulse monitor device to the subject 3000, the peelable protective layer 302 is removed to reveal the adhesive layer underneath. After the adhesive layer has been exposed, the adhesive pad 102 is then placed on the subject’s body as is indicated on the indicia either provided on the adhesive backing 302 or the activating tab 106.

[0149] Once the pulse monitor device has been successfully positioned in the correct location on the subject’s body, the activating tab 106 may be pulled in a direction indicated on the activating tab 106 to turn on the pulse monitoring device 1000. It will be understood by theskilled person that other means of attaching the pulse monitoring device 1000 to the body, as described in this document, may be used with similar utility.

[0150] With the pulse monitor device now switched on, the operator may observe the readout in either a visual or audible form to indicate a pulse or pulseless state, indicating what course of action is required for the subject 3000.

[0151] With reference to Figure 17, a method related to the use of the pulse monitoring device 1000 is shown. Initially, the pulse monitoring device 1000, embodiments of which have been exemplified above, is placed on a subject’s body shown as step 1701 , and is either powered on prior to placement or after the device has been placed on the subject’s body.

[0152] During the mounting process 1701 , a baseline pressure measurement is taken as is shown at step 1703. Using pressure sensors as have been previously described, a determination of whether the applied pressure is within a desired, or reference range, is determined at step 1704. It will be understood by the skilled person that the desired pressure may be determined based on a number of factors such as a received calibration signal and the signal to noise ratio in respect to the received signal. Other factors may include an optimal pressure value which may be determined through experimentation. The pressure is monitored as is shown at step 1705 until the desired pressure threshold value is reached. If the desired pressure is not reached initially, the device may be adjusted on the subject and steps 1703 and 1704 repeated. Once the desired pressure is achieved, an indicator may notify the operator that a desired pressure has been obtained. Then each sensor goes through a calibration process, and a baseline value is stored for each sensor as is shown at step 1706.

[0153] Once the sensors have proceeded through a calibration process, each sensor will acquire sensor data 1707 such as pressure data relating to a pulse signal or other relevant biological signal. Upon acquisition of the relevant biological signal, baseline and other external noise is negated to retrieve a signal of interest as is shown at step 1709.

[0154] Once a valid signal is acquired, it may be filtered to remove noise and other unwanted noise as is shown at step 171 1. After the signal of interest has been filtered, the step of removing motion artefacts is performed, shown as step 1713. Once motion artefacts have been removed, the extraction of pulse signals is performed as is shown at step 1715. This step may include peak detection and waveform analysis as some examples. Cross-sensor validation such as voting logic or weighted confidence is then performed at step 1717. After the preceding steps,a determination of a valid pulse is determined at step 1719 resulting in a display 1721 of either an indicator indicating a valid pulse, or an indicator of no valid pulse which may be displayed on a display device.

[0155] Figure 18 provides a flow chart associated with an embodiment of the present invention utilising a PPG sensor. At step 1801 , the pulse monitoring device is placed on a person’s body. After placement the pulse monitoring device 1000 is turned on. However, the device may also be turned on prior to placement on the person’s body. Once the pulse monitoring device 1000 is placed on the person’s body, a baseline pressure measurement is taken at step 1803, after which the pressure is measured to determine if it falls within a reference range appropriate to the specific measurement site. The pressure measurement is monitored until it falls within the desired range. Once the pressure has reached a desired range suitable for PPG sensing, the PPG sensor will enter a calibration step shown as 1807.

[0156] The calibration step 1807 includes a recording of ambient light level and baseline reflection from the person’s skin. Once the step of calibration 1807 is preformed the PPG sensor will acquire data shown as step 1809. The step of 1809 may include a continual sensing loop where the sensor may sample data at periodic intervals. After step 1809, the baseline levels and ambient light signals detected in step 1807 are then subtracted from the signals of interest to provide a delta signal shown in step 1811. The signal is then filtered at step 1813 using various filtering techniques including bandpass and smoothing filtering methods. At step 1815, motion artefacts are removed with the use of accelerometer data which is obtained from accelerometer sensors provided in the pulse monitoring device 1000. After motion artefacts are removed at step 1815, pulse features are extracted using peak detection and waveform analysis shown as step 1817. Cross sensor validation is then performed on the signal output at step 1817 as is shown at step 1818. This is then followed by the step of pulse detection shown as 1819. After which the status, designating a valid or invalid pulse is displayed at step 1821 . This process continues with the PPG sensor acquisition shown as step 1809.

[0157] Figure 19 shows a flow chart associated with an embodiment of the invention utilising both a PPG sensor and a non-PPG sensor used in parallel to provide a level of redundancy and with the aim of providing improved accuracy. At step 1901 , the pulse monitoring device 1000 is placed on the person’s body and powered on. The device may be powered on before or after placement. Step 1901 is followed by the step of performing baseline pressure measurement shown as step 1903. The baseline pressure is monitored at step 1904 until the pressure reachesa desired pressure range which is predetermined as is shown at step 1905. Sensor calibration is performed for the PPG and non-PPG sensors as is shown at steps 1906 and 1923 respectively. The sensor calibration of both the non-PPG sensors and the PPG sensors are performed simultaneously. After the calibration steps shown as steps 1906 and 1923, data is then acquired from the non-PPG and PPG sensors simultaneously shown as steps 1925 and 1908 respectively. At steps 1927 and 191 1 , baseline signals are subtracted to provide a delta signal for the non-PPG and PPG signals respectively. The respective, non-PPG and PPG signals are then filtered at steps 1928 and 1913. This is followed by the removal of motion artefacts using accelerometer data at steps 1915 and 1930. The accelerometer data is provided by an accelerometer sensor associated with the pulse monitoring device 1000. Once motion artefact removal has been performed at steps 1918 and 1934, pulse features are extracted at steps 1918 and 1934. The output data from the non-PPG and PPG sensors are then combined where comparison logic is performed at step 1919, after which the step of pulse detection is performed shown as step 1921 , the output of step 1921 being used to display the pulse status at step 1922 to indicate whether a valid pulse has been detected.

[0158] It will be appreciated that the processing steps illustrated in Figures 17 to 19 are exemplary only and additional or alternate processing steps may be performed.INTERPRETATION

[0159] Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as "processing," "computing," "calculating," “determining”, analysing” or the like, refer to the action and / or processes of a computer or computing system, or similar electronic computing device, that manipulate and / or transform data represented as physical, such as electronic, quantities into other data similarly represented as physical quantities.

[0160] Furthermore, the terms “real-time” and the like, are to be understood in their usual sense, that generally being related to a system in which input data is processed generally within milliseconds with low latency.

[0161] In a similar manner, the term "processor" may refer to any device or portion of a device that processes electronic data, e.g., from registers and / or memory to transform that electronic data into other electronic data that, e.g., may be stored in registers and / or memory.A “computer” or a “computing machine” or a "computing platform" may include one or more processors.

[0162] Reference throughout this specification to “one embodiment”, “some embodiments” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases “in one embodiment”, “in some embodiments” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[0163] As used herein, unless otherwise specified the use of the ordinal adjectives "first", "second", "third", etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

[0164] In the claims below and the description herein, any one of the terms comprising, comprised of or which comprises is an open term that means including at least the elements / features that follow, but not excluding others. Thus, the term comprising, when used in the claims, should not be interpreted as being limitative to the means or elements or steps listed thereafter. For example, the scope of the expression a device comprising A and B should not be limited to devices consisting only of elements A and B. Any one of the terms including or which includes or that includes as used herein is also an open term that also means including at least the elements / features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.

[0165] It should be appreciated that in the above description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, Fig., or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claims require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into thisDetailed Description, with each claim standing on its own as a separate embodiment of this disclosure.

[0166] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the disclosure, and form different embodiments, as would be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0167] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the disclosure may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0168] Similarly, it is to be noticed that the term coupled, when used in the claims, should not be interpreted as being limited to direct connections only. The terms "coupled" and "connected," along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Thus, the scope of the expression a device A coupled to a device B should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may be a path including other devices or means. "Coupled" may mean that two or more elements are either in direct physical, electrical or optical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other.

[0169] Embodiments described herein are intended to cover any adaptations or variations of the present invention. Although the present invention has been described and explained in terms of particular exemplary embodiments, one skilled in the art will realize that additional embodiments can be readily envisioned that are within the scope of the present invention.

Claims

The claims defining the invention are as follows:1 . A pulse monitor device, the device including: an attachment formation adapted to be removably attachable to a region of a subject’s body; at least one sensor module attached to the attachment formation and including a processor adapted to detect a pulse signal indicative of a presence or absence of a pulse from the subject; and at least one indicator responsive to the pulse signal to provide an indication of the presence or absence of the pulse.

2. The pulse monitor device of claim 1 , wherein the region of a subject’s body includes the subject’s neck.

3. The pulse monitor device of claim 1 or claim 2, wherein the pulse monitor device is adapted to detect a pulse on the subject’s carotid artery.

4. The pulse monitor device of claim 1 or claim 2, wherein the pulse monitor device is adapted to detect a pulse over the subject's thyroid.

5. The pulse monitor device of any one of the preceding claims, wherein the at least one indicator includes a visual indicator.

6. The pulse monitor device of any one of the preceding claims, wherein the at least one indicator includes an audio indicator.

7. The pulse monitor device of any one of the preceding claims, wherein the at least one indicator includes at least one LED.

8. The pulse monitor device of any one of the preceding claims, wherein the at least one indicator includes an LCD display.

9. The pulse monitor device of any one of the preceding claims, wherein the at least one sensor module includes a photoplethysmogram (PPG) device.

10. The pulse monitor device of any one of the preceding claims, wherein the at least one sensor module includes a piezoelectric device.1 1 . The pulse monitor device of any one of the preceding claims, wherein the at least one sensor module includes an electrocardiogram (ECG) device.

12. The pulse monitor device of any one of the preceding claims, wherein the at least one sensor module includes a microphone adapted to detect a pulse from a detected acoustic signal.

13. The pulse monitor device of any one of the preceding claims, wherein the at least one sensor module includes a pressure sensor.

14. The pulse monitor device of claim 13, wherein the pressure sensor includes a plurality of pistons adapted to detect pulse signals based on changes in fluid or gas pressure.

15. The pulse monitor device of claim 13, wherein the pressure sensor includes one or more of: a capacitive sensor, an interdigitated electrode array, a strain gauge, a piezoresistive sensor, or a force-sensitive resistor.

16. The pulse monitor device of claim 13, wherein the pressure sensor includes a resilient material operably connected to a pressure sensor through which pulse signals are detected.

17. The pulse monitor device of claim 13, wherein the pressure sensor includes a plurality of spheres through which a pressure signal is transferred, each sphere being associated with a strain gauge for detecting movements of each sphere in accordance with pressure from a pulse signal.

18. The pulse monitor device of any one of the preceding claims, wherein the at least one sensor module includes an array of accelerometers mounted to a flexible surface and adapted to sense a pulse signal on a person’s body.

19. The pulse monitor device of any one of the preceding claims, wherein the attachment formation includes an adhesive pad.

20. The pulse monitor device of claim 19, wherein the adhesive pad is formed from a silicone or acrylic adhesive.21 . The pulse monitor device of any one of the preceding claims, wherein the at least one sensor module comprises a spatial array of sensing elements disposed across a flexible substrate, wherein the processor is configured to determine the presence of pulsatile flow by analysing signal features across two or more sensing locations.

22. The pulse monitor device of any one of the preceding claims, wherein the sensor module includes at least one sensing element positioned outside the expected arterial region, and wherein the processor is configured to use signals from that element as a control input for undesired artefact suppression or validation of pulsatile flow detection.

23. The pulse monitor device of any one of the preceding claims, wherein the sensor module includes at least one transducer that produces a periodic signal of known amplitude and frequency such that the resulting sensor output can be calibrated to account for individual variations in coupling to the person’s body.

24. The pulse monitor device of any one of the preceding claims, wherein the attachment formation includes a resilient structure adapted to expandably attach to a person’s body.

25. The pulse monitor device of any one of the preceding claims, further including an accelerometer.

26. The pulse monitor device of claim 25, wherein the accelerometer is adapted to generate a signal indicative of non-cardiac motions.

27. The pulse monitor device of claim 26, wherein the non-cardiac motions include breathing, swallowing and / or movement of the subject, or CPR conducted on the subject.

28. The pulse monitor device of any one of the preceding claims, wherein the processor is configured to compare time-aligned signals from different sensor modalities, and to confirm a pulsatile event only when a threshold degree of correlation is detected between the modalities.

29. The pulse monitor device according to claim 26 or claim 27, wherein the processor is adapted to filter the signal indicative of the non-cardiac motions from the pulse signal.

30. The pulse monitor device according to any one of the preceding claims, including a body that houses the processor.31 . The pulse monitor device according to claim 30, including an activating tab initially attached to the body and selectively removable to activate an operative state of the pulse monitor device.

32. The pulse monitor device of claim 31 , wherein the activating tab includes visible indicia providing instructions for use of the pulse monitor device.

33. The pulse monitor device according to any one the preceding claims, wherein the at least one sensor module includes a plurality of separately disposed sensors.

34. The pulse monitor device according to any one of claims 30 to 32, including a pair of sensors disposed about the body, wherein the attachment formation includes an adhesive pad and wherein the body is centrally located on the adhesive pad.

35. The pulse monitor device according to claim 34, wherein the adhesive pad includes a pair of wings that extend from the body around the pair of sensors.

36. The pulse monitor device according to any one of the claims 19, 20, 34 or 35, wherein the adhesive pad includes a peelable protective layer to reveal the adhesive layer.

37. The pulse monitor device according to any one of the preceding claims, wherein the pulse monitor device includes a data port for communicating data between the processor and an external device.

38. The pulse monitor device according to any one of the preceding claims, including a wireless device adapted for wireless connectivity for transferring data to and / or from the pulse monitor device.

39. The pulse monitor device according to any one of the preceding claims, wherein the indicator is adapted to provide audio and / or visual instructions for a person to commence or perform CPR on the subject.

40. The pulse monitor device according to any one of the preceding claims, wherein the indicator is adapted to provide audio and / or visual feedback indicating a quality of CPR being performed on the subject.41 . A pulse monitor device, the device including: an attachment formation adapted to be removably attachable to a region of a subject’s body; at least one sensor attached to the attachment formation, the at least one sensor being adapted to detect a signal indicative of a pulse of the subject and, in response, generate a sensor signal; a processor, functionally connected to at least one sensor and configured to process the sensor signal received from at least one sensor to detect a presence or absence of a pulse of the individual; and at least one indicator, functionally connected to the processor to provide an indication of the presence of the pulse of the individual.

42. The pulse monitor device according to claim 41 including a power source and a card, removably attachable to the pulse monitor device and configured to transfer powerfrom the power source to the pulse monitor device when the card is detached from the pulse monitor device.

43. The pulse monitor device according to claim 41 or claim 42 wherein the region of the individual’s body includes the neck region.

44. The pulse monitor device according to any one of the preceding claims wherein the attachment formation is configured to achieve a desired pressure on the subject's body without manual intervention.

45. The pulse monitor device according to any one of the preceding claims wherein the attachment formation is configured to adjust the applied pressure on the subject's body to a desired value iteratively based on the disposed pressure sensor value.

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