Vital Sign Monitoring Device

Abstract

A monitoring device configured to be removably attached to the neck of a patient comprises an optical unit (10) for monitoring one or more vital signs and an acoustic unit (20) for monitoring one or more vital signs.

Description

Technical Field

[0001] The present invention relates to a monitoring device configured to be removably attached to a patient's neck for monitoring the patient's vital signs.

Background Art

[0002] In all types of medical care such as hospitals or pre-hospital care, emergency rescue, emergency medicine, anesthesia, etc., the top priority is to secure the airway. Since even a short loss of airway patency can endanger the patient's life, monitoring of respiration and other vital signs is extremely important.

[0003] To manually monitor a patient's airway and determine whether the vital signs are appropriate, a significant amount of clinical training and awareness are required, and it is necessary to continuously evaluate the airway to detect a decrease in airway patency. Furthermore, this is difficult when it is necessary to monitor multiple patients at once in stressful emergency situations, crowded hospitals, field hospitals, mass casualty incidents, in-hospital transfers, military facilities, etc.

[0004] Monitoring devices may be useful for medical staff to monitor the airway, but usually they are bulky or do not provide reliable real-time direct monitoring of the airway. Instead, these devices usually trigger an alarm when airway insufficiency is detected, but this detection is often too late and can lead to the patient suffering from complex conditions such as decreased oxygen saturation and arrhythmia.

[0005] Conventional pulse oximetry monitors (measured at the fingertip) are not reliable in patients with hypothermia, shock, or low blood pressure because the signs of airway obstruction are delayed.

[0006] Capnography is one of the more robust monitoring methods, but it requires expensive sensors and is not very suitable for many situations.

Summary of the Invention

[0007] Therefore, there is a need for monitoring devices that can easily and reliably detect and monitor vital signs, so that healthcare professionals can easily monitor them in both emergency and non-emergency situations. Furthermore, there is a need for devices that can provide earlier and more decisive warnings of loss of airway patency. A device that combines ease of use and versatility is required. [Means for solving the problem]

[0008] From a first perspective, a monitoring device is provided that is configured to be detachably attached to the patient's neck, the monitoring device including an optical unit for monitoring one or more vital signs and an acoustic unit for monitoring one or more vital signs.

[0009] The optical unit may include an optical sensor. For example, the optical sensor may be a reflective pulse oximeter.

[0010] Vital signs measured by optical sensors may include one or more (preferably all) of the following: blood oxygen saturation, pulse rate, and respiratory rate.

[0011] To measure blood oxygen saturation, optical sensors may measure the reflectance of light at two or more wavelengths. The first wavelength is the wavelength at which oxygenated and deoxygenated hemoglobin absorb light the same amount, while the second wavelength is the wavelength at which oxygenated and deoxygenated hemoglobin have a significant difference in light absorption. Using known algorithms, blood oxygen saturation can be determined based on the reflectance measurements.

[0012] Measuring pulse rate using an optical sensor may require measuring the reflectance of a single wavelength of light. When the heart beats, blood pulsates through the capillaries at the same frequency as the heartbeat. This pulsation means a change in the volume of blood within the capillaries. This change in volume alters the amount of light absorbed by the blood, i.e., the amount of light reflected. Therefore, pulse rate can be estimated by an optical sensor by measuring the time-dependent variation of the reflected light. Known algorithms can be used to determine the pulse rate based on the time-dependent variation of the reflectance.

[0013] Since respiratory activity affects the resulting photoplethysmography waveform, it is possible to extract respiratory rate information using optical sensors. Respiratory rate can be determined based on the photoplethysmography waveform using known algorithms.

[0014] The optical unit may include an illumination unit capable of emitting light from at least two different wavelength ranges onto the skin. The illumination unit may consist of a single light source that can be controlled to emit light from at least two different wavelength ranges. The light source may be an LED. Alternatively, the optical unit may consist of two light sources, each configured to emit light from a different wavelength range. The light sources may also be LEDs. In one example, the first wavelength range has a peak at 805 nm and the second wavelength range has a peak at 660 nm.

[0015] The acoustic unit may include an acoustic sensor. For example, the acoustic sensor may be a piezoelectric sensor or a microphone. In embodiments where the acoustic sensor is a microphone, the microphone may be a MEMS microphone. In embodiments where the acoustic sensor is a piezoelectric sensor, the piezoelectric sensor may include a piezoelectric disc in a cup having a membrane positioned toward the patient's skin.

[0016] Vital signs measured by acoustic sensors include one or more (preferably all) of the following: respiratory rate, pulse rate, and airway patency.

[0017] Airway patency is an indicator of the degree of airway obstruction. Monitoring devices may monitor signs of partial or complete airway obstruction.

[0018] Breath sounds when the airway is partially obstructed differ from those when the airway is open. When airway patency is reduced, the normal whispering sound of air passing through the airway becomes quieter, and other sounds such as wheezing, rattling, and snoring may be heard. Therefore, relatively loud sounds (compared to normal breathing sounds), or repeated snoring, wheezing, or rattling may indicate that the airway is impaired. Such sounds can be identified, for example, using a trained machine learning / deep learning model that has been trained on data containing such sounds.

[0019] If the airway is completely obstructed, a decrease in airway patency can be determined by detecting a drop in respiratory rate to zero.

[0020] When airway patency is lost, the pulse rate initially increases, and then decreases as blood oxygen saturation decreases. The rate of respiratory effort also initially increases and then decreases, but no actual breathing occurs because the airway is obstructed. As a result, the diaphragm simply contracts, creating negative pressure inside the chest. Loss of airway patency eventually leads to cardiac arrest. This can occur as early as 2 minutes or as late as 10 minutes after breathing stops, depending on the patient's age and condition. Monitoring devices ensure that patients receive treatment before their condition deteriorates by detecting loss of airway patency.

[0021] Respiratory rate and pulse rate can be measured by acoustic sensors simply by listening to the sounds associated with breathing in and out, and the pulse, respectively. Known algorithms may be used to determine the respiratory rate and pulse rate from the measured sounds.

[0022] Using two different sensor types within a monitoring device can help improve the reliability of the measured vital signs. Each sensor functions as a backup or check for the values measured by the other sensor. For example, if the values of the same vital sign measured by each sensor are different, an alert indicating a possible malfunction in one of the sensors may be issued from the monitoring device. For example, the measurement of the respiration rate and pulse rate from an acoustic sensor can be used as a check for the respiration rate and pulse rate measured by an optical sensor.

[0023] By placing the monitoring device on top of the head, it is possible to measure the respiration rate, pulse rate, blood oxygen saturation, and airway patency more accurately and timely without the need for a bulky monitoring device.

[0024] The acoustic unit can include an environmental noise sensor configured to measure unwanted environmental noise (i.e., noise unrelated to the patient's vital signs) so that such unwanted environmental noise can be subtracted from the signal measured by the first acoustic sensor. The environmental noise sensor can be, for example, a microphone.

[0025] The acoustic unit can include an acoustic sensor and a data acquisition module configured to amplify the sound detected by the acoustic sensor and convert it into a digital signal.

[0026] Similarly, the optical unit can include a data acquisition module that includes an optical sensor.

[0027] The monitoring device can include a signal processing module capable of receiving digital signals from the data acquisition modules of the optical unit and the acoustic unit.

[0028] The signal processing module can be configured to receive digital signals from the data acquisition modules of the optical unit and the acoustic unit, and filter the digital signals to remove noise from the digital signals.

[0029] The monitoring device can include a data analysis module configured to determine the respiration rate, pulse rate, blood oxygen saturation, and airway patency. If necessary, the data analysis module determines the respiration rate, pulse rate, blood oxygen saturation, and airway patency based on the data output from the signal processing module.

[0030] The monitoring device can include a single processor configured to execute the processes performed by the data acquisition modules of the acoustic unit and the optical unit, the signal processing module, and the data analysis module.

[0031] In the above, an embodiment in which the monitoring device includes a single processor that receives data streams from both the optical sensor and the acoustic sensor is described. In another embodiment, the monitoring device is composed of two processors, and each processor is dedicated to analyzing a single data stream. The first processor is dedicated to analyzing the data from the optical unit, and the second processor is dedicated to analyzing the data from the acoustic unit. Then, each processor is composed of a data acquisition module, a signal processing module, and a data analysis module.

[0032] The monitoring device may be set to self-calibrate when worn and activated on the patient's neck. For example, the monitoring device can compare the sensor signal with an internal or external reference.

[0033] Monitoring devices can monitor one or more vital signs by taking measurements at a predetermined sampling rate. Acoustic and optical sensors may have the same sampling rate, or they may have different sampling rates. The predetermined sampling rate can range from 5 to 50 measurements per second, for example, from 10 to 30 measurements per second, and can optionally be set to approximately 20 measurements per second.

[0034] The monitoring device may recalculate the value of one or more vital signs using data from a predetermined measurement time interval (e.g., 10 to 20 seconds), or it may recalculate the values ​​on a rolling basis at predetermined intervals (e.g., 1 to 5 seconds). These values ​​may be the same or different for each vital sign.

[0035] For example, a monitoring device recalculates the respiratory rate every 5 seconds based on data acquired in the previous 20 seconds. Because pulse rate is measured more frequently than respiratory rate, pulse rate may be updated more frequently and based on data acquired in shorter intervals. Therefore, for example, a monitoring device could recalculate the pulse rate every second based on data acquired in the previous 10 seconds.

[0036] As mentioned earlier, to measure blood oxygen saturation, optical sensors may measure reflectance using two or more wavelengths of light. Therefore, measuring blood oxygen saturation may involve applying a sequence of light wavelengths, measuring the reflectance during that sequence, and then calculating an updated blood oxygen saturation value at the end of each sequence.

[0037] A monitoring device may include a display for showing measurements of one or more vital signs. As can be seen from the above, the display is integrated into the monitoring device and is also present in the device worn around the patient's neck.

[0038] Monitoring devices can be configured to monitor vital signs for an initial period before the measured values ​​are displayed on the device. This has the advantage of providing accurate vital sign measurements before the values ​​are displayed.

[0039] The monitoring device may update the displayed measurements of one or more vital signs at predetermined display intervals. The predetermined display intervals range from 5 to 30 seconds, for example, from 5 to 20 seconds.

[0040] Equipped with a monitoring device and a display that shows the results around the neck, healthcare professionals can easily view a patient's vital signs without having to periodically reassess the airway manually. Therefore, healthcare professionals can check whether a patient's vital signs are at an acceptable level, and if not, the patient should be immediately taken into attention.

[0041] Monitoring devices are particularly useful when it is necessary to monitor multiple patients simultaneously and provide a dedicated monitoring device for each patient.

[0042] The monitoring device can be attached to the patient's neck using adhesive pads, allowing for non-invasive attachment. The adhesive pads also facilitate attachment, eliminating the need for clinical training. This is preferable to complex and invasive procedures for airway monitoring, which often require considerable equipment.

[0043] The monitoring device can be removed by pulling it away from the patient's neck. Then, remove the adhesive pads and replace them with new ones if necessary.

[0044] The monitoring device can be attached to the patient's neck using a strap or band. Some straps and bands are non-constricting and are simple and easy to attach. This is useful in situations where adhesive pads are insufficient or adequate safety cannot be ensured, such as when the patient is being transported or when procedures are being performed that could move the patient and cause the monitoring device to fall off.

[0045] Non-constrictive straps or bands can be sized so as not to encircle the entire neck.

[0046] Because monitoring devices are simple to use, even untrained individuals can wear them and monitor a patient's vital signs. This is particularly beneficial for home use and is an advantage over capnography-based systems that require many pieces of equipment. Furthermore, monitoring devices are small and lightweight (important considering they are worn around the neck), portable (i.e., easily carried by hand without assistance), and easy to store. Monitoring devices can also be operated with just one hand.

[0047] Monitoring devices can be configured with predefined tolerance ranges for each of one or more vital signs (including upper and lower limits within which the vital signs should fall). Alternatively, tolerance ranges may be set by a user with a certain level of authority (not necessarily owned by a healthcare professional), depending on the patient and / or environment. This allows for adjustment of tolerance ranges when a particular patient's vital signs are normally outside the expected range. Or, expectations may differ depending on the environment, or healthcare professionals may be working under excessive time pressure to respond to a patient only when vital signs reach a specific point that would have otherwise required attention (for example, when dealing with multiple patients in an emergency).

[0048] A timer may start if one or more vital signs exceed acceptable levels. If vital signs do not return to acceptable levels within a pre-set time limit, the monitoring device may issue an alert. This allows healthcare workers to immediately warn that the patient's airway may be obstructed and immediate attention is required. Knowing that significant changes in vital signs trigger an alert eliminates the need for constant monitoring of the patient or frequent manual airway assessments. This is particularly useful when one caregiver is monitoring multiple patients simultaneously. Early detection of loss of airway patency can significantly improve patient survival rates.

[0049] If the monitoring device provides two values ​​for the same vital sign (for example, pulse rate and respiratory rate, which can be measured by an acoustic sensor and an optical sensor, respectively), in one embodiment, the values ​​for a given vital sign from both the acoustic sensor and the optical sensor must be out of range before the timer starts. Alternatively, the timer may start when only one of the values ​​from either the acoustic sensor or the optical sensor goes out of range.

[0050] Monitoring devices may have time limits, but depending on the patient and environment, users with a certain level of access may also set these time limits (i.e., they are not necessarily owned by healthcare professionals) (i.e., time limits are customizable).

[0051] The acceptable range for blood oxygen saturation is, for example, 90% to 100%. If blood oxygen saturation exceeds this range, a timer will start, and if blood oxygen saturation does not return to the acceptable range within a preset time limit (for example, 15 seconds), an alert may be issued.

[0052] The acceptable range for pulse rate is, for example, 50 to 120 beats per minute. If the blood pulse rate exceeds this range, a timer will start, and if the pulse rate does not return to the acceptable range within a pre-set time limit (for example, 15 seconds), an alert may be issued.

[0053] The acceptable range for respiratory rate is, for example, 8 to 27 breaths per minute. If the respiratory rate exceeds this range, a timer will start, and if the respiratory rate does not return to the acceptable range within a pre-set time limit (for example, 15 seconds), an alert may be issued.

[0054] If vital signs return to an acceptable range within a predetermined time limit, the timer may be reset to 0. Vital sign monitoring may then be continued as usual.

[0055] Monitoring devices can be configured to monitor the rate of change of vital sign measurements, for example, their first derivative with respect to time. An alert may be issued if the rate of change of vital sign measurements falls outside a preset tolerance range or exceeds a predetermined limit over a preset period. For pulse rate and respiratory rate, the preset range may range from negative to positive rates of change. In other words, an alert is triggered if both the decrease and increase in vital signs fall outside the preset range. For blood oxygen saturation, since only a decrease may be a concern, an alert may be issued if a negative rate of change occurs where the absolute value (modulus) exceeds a predetermined limit over a preset period.

[0056] If the monitoring device provides two values ​​for the same vital sign (for example, pulse rate and respiratory rate, which can be measured by an acoustic sensor and an optical sensor, respectively), in one embodiment, the percentage change values ​​of the vital sign measurements from both the acoustic and optical sensors must fall out of range before the timer starts. Alternatively, the timer can be started when only one of the percentage change values ​​of the vital sign measurements from either the acoustic or optical sensor falls out of range.

[0057] The timer can be started when the rate of change in vital sign measurements falls outside a predetermined tolerance range or exceeds a predetermined limit.

[0058] For example, an alert may be issued if the patient's respiratory rate changes by more than ±30% (or, optionally, if it remains outside this range for 10 minutes).

[0059] For example, an alert may be issued if the patient's pulse rate changes by more than ±40% (or, optionally, if it remains outside this range for 10 minutes).

[0060] For example, an alert may be issued if a patient's blood oxygen saturation drops below 5% (or, optionally, if this limit is exceeded for 10 minutes).

[0061] If the rate of change in vital sign measurements returns to a predetermined acceptable range / limit within a pre-set time limit, the timer can be reset to 0. After that, vital sign monitoring may be continued as usual.

[0062] Monitoring devices may have predetermined tolerance ranges, limits, and timeframes for the rate of change in vital sign measurements, but these may also be set by a user with a certain level of authority, depending on the patient and environment (i.e., not necessarily owned by a healthcare professional).

[0063] In the above case, an alert can be issued even if one or more vital signs are within a predetermined acceptable range for their respective values.

[0064] A timer may start if one or more vital signs (e.g., respiratory rate or pulse rate) recorded by optical and acoustic sensors diverge beyond a preset threshold. If the deviation of vital signs recorded by optical and acoustic sensors does not return to below the threshold within a preset time limit, the monitoring device may issue an alert. This is useful as it can indicate a sensor malfunction to healthcare professionals. The monitoring device can set thresholds for how much one or more vital signs from each sensor should diverge. The divergence thresholds and time limits, as well as the predefined tolerance ranges for vital signs, are stored in the monitoring device. Different vital signs may have different thresholds and time limits.

[0065] The acceptable divergence in respiratory rate is, for example, three breaths per minute. If the values ​​measured by the optical and acoustic sensors deviate beyond this, the timer may be activated. If the divergence does not fall below the threshold within a preset time limit (e.g., one minute), an alert may be issued.

[0066] The acceptable divergence in pulse rate is, for example, 12 beats / minute. If the values ​​measured by the optical sensor and acoustic sensor diverge beyond this, the timer may be activated. If the divergence does not fall below the threshold within a preset time limit (e.g., 30 seconds), an alert may be issued.

[0067] If the divergence returns to below the set threshold within the set time limit, the timer may be reset to 0. After that, vital sign monitoring may be continued as usual.

[0068] Monitoring devices may also be configured to detect reduced or lost airway patency. If one or more snoring, wheezing, or rattling sounds are detected, a timer may be started, and an alert may be issued if the snoring, wheezing, or rattling continues for a predetermined time. The predetermined time may be, for example, 5 to 10 minutes. The time frame may be set considering the benefit of not issuing alarms too frequently, especially when an alarm is not justified (for example, if the patient is unconscious, they may make sounds that could trigger an alarm), as healthcare workers may become exhausted from responding to alarms, which could lead to them ignoring them.

[0069] If the airway is completely obstructed, a decrease in airway patency can be determined by detecting a drop in respiratory rate to zero. When the respiratory rate drops to zero, a timer starts, and an alert may be issued after a set time (usually about 20 seconds).

[0070] Alerts can be auditory alerts, such as alarms. Alternatively, they can be visual alerts, such as indicator lights. In yet another case, a processor may issue both audible and visual alerts. Auditory alerts are beneficial because they are easier for healthcare workers to notice than visual alerts. However, in certain environments, such as military situations, auditory alerts may be undesirable. In such cases, auditory alerts can be deactivated, and healthcare workers can rely solely on visual alerts, such as indicator lights.

[0071] If a monitoring device is experiencing low power, it may issue a maintenance alert. This maintenance alert may use auditory or visual alerts.

[0072] This alert can also be used to inform healthcare professionals that the device is functioning correctly. For example, monitoring devices may issue alerts periodically.

[0073] The history of one or more vital signs and / or alerts can be stored in the monitoring device's integrated storage. This allows healthcare professionals to monitor a patient's vital signs over a long period, as well as when alerts occurred and how quickly they were responded to.

[0074] The monitoring device may also include a wireless interface (e.g., a Bluetooth® interface) for communicating with external devices. These external devices may include, for example, mobile phones, laptops, desktop computers, and tablets. The aforementioned predefined ranges and thresholds can be customized using external devices (e.g., by a user with high-level privileges, not necessarily owned by a healthcare professional). A single external device may be able to communicate with multiple monitoring devices, which is useful when monitoring multiple patients simultaneously. The wireless interface can also be used to send a history of one or more vital signs and / or alerts to the external device.

[0075] Monitoring devices can also transmit the history of one or more vital signs and / or alerts to a remote storage server via Wi-Fi or 3G / 4G / 5G networks. The remote storage server can receive data simultaneously from multiple monitoring devices. This allows for the formation of a complete database from numerous monitoring devices, enabling remote monitoring from a central location. The remote storage server may be monitored from a central location. For example, in a field hospital or military operation, it might be located where the nearest doctor or nurse cannot attend to all patients simultaneously.

[0076] Monitoring devices may send data to an external device instead of directly to a remote storage server, containing the history of one or more vital signs or alerts, and this external device may relay the data to the remote storage server.

[0077] In a second aspect, a method is provided for monitoring one or more vital signs of a patient using a monitoring device, the monitoring device comprising an optical unit for monitoring one or more vital signs and an acoustic unit for monitoring one or more vital signs, the method comprising attaching the monitoring device to the patient's neck to monitor one or more vital signs.

[0078] This method allows monitoring of a patient's airway patency, respiratory rate, pulse rate, and blood oxygen saturation without requiring continuous reassessment by healthcare professionals.

[0079] One or more vital signs can be monitored by taking measurements at a predetermined sampling rate. The acoustic unit and optical unit may have the same sampling rate, or they may have different sampling rates. The predetermined sampling rate can be 5 to 50 measurements per second, for example, 10 to 30 measurements per second, or optionally approximately 20 measurements per second.

[0080] This method may involve recalculating the values ​​of one or more vital signs on a rolling basis at predetermined intervals (e.g., 1 to 5 seconds) using data from predetermined measurement time intervals (e.g., 10 to 20 seconds). These values ​​may be the same or different depending on the vital sign.

[0081] For example, one method could be to recalculate the respiratory rate every 5 seconds based on data acquired in the previous 20 seconds. Since pulse rate is measured more frequently than respiratory rate, pulse rate may be updated more frequently and based on data acquired in shorter time intervals. Therefore, for example, this method could recalculate the pulse rate every second based on data acquired in the previous 10 seconds.

[0082] As mentioned earlier, to measure blood oxygen saturation, optical sensors may measure reflectance using two or more wavelengths of light. Therefore, measuring blood oxygen saturation may involve applying a sequence of light wavelengths, measuring the reflectance during that sequence, and then calculating an updated blood oxygen saturation value at the end of each sequence.

[0083] This method may involve monitoring vital signs for an initial period before the vital sign measurements are displayed on the device. This has the advantage of obtaining accurate vital sign measurements before displaying them.

[0084] This method may include determining whether one or more vital signs are within or outside a predefined acceptable range.

[0085] A timer can be started if one or more vital signs are outside their respective predefined ranges. If the vital signs do not return to an acceptable range within a pre-set time limit, the method includes issuing an alert, which may be an auditory and / or visual alert. This alerts healthcare workers as soon as the patient shows signs of loss of airway patency, allowing the patient to receive immediate attention. Using auditory alerts means that healthcare workers do not need to directly monitor the monitoring device, but only need to be nearby so they can hear the auditory alert. Auditory alerts may also be alarms.

[0086] Visual alerts are useful in situations where auditory alerts are unsuitable, such as in military environments.

[0087] The acceptable range for blood oxygen saturation is, for example, 90% to 100%. If blood oxygen saturation exceeds this range, a timer will start, and if blood oxygen saturation does not return to the acceptable range within a preset time limit (for example, 15 seconds), an alert may be issued.

[0088] The acceptable pulse rate range is, for example, 50 to 120 beats per minute. If the pulse rate exceeds this range, a timer will start, and if the pulse rate does not return to the acceptable range within a pre-set time limit (for example, 15 seconds), an alert may be issued.

[0089] The acceptable range for respiratory rate is, for example, 8 to 27 breaths per minute. If the respiratory rate exceeds this range, a timer will start, and if the respiratory rate does not return to the acceptable range within a pre-set time limit (for example, 15 seconds), an alert may be issued.

[0090] This method may further include monitoring the divergence of one or more vital signs (e.g., respiratory rate, pulse rate, etc.) measured by acoustic sensors and optical sensors, respectively.

[0091] A timer may be triggered if one or more vital signs monitored by both the acoustic and optical sensors diverge above a threshold. If the divergence between the vital signs recorded by the optical and acoustic sensors does not fall below the threshold within a pre-set time limit, this method may further include issuing an alert. As described above, the alert may be an auditory or visual alert.

[0092] The acceptable divergence in respiratory rate is, for example, three breaths per minute. If the values ​​measured by the optical and acoustic sensors deviate beyond this, the timer may be activated. If the divergence does not fall below the threshold within a preset time limit (e.g., one minute), an alert may be issued.

[0093] The acceptable divergence in respiratory rate is, for example, three breaths per minute. If the values ​​measured by the optical and acoustic sensors deviate beyond this, the timer may be activated. If the divergence does not fall below the threshold within a preset time limit (e.g., one minute), an alert may be issued.

[0094] The acceptable divergence in pulse rate is, for example, 12 beats / minute. If the values ​​measured by the optical sensor and acoustic sensor diverge beyond this, the timer may be activated. If the divergence does not fall below the threshold within a preset time limit (e.g., 30 seconds), an alert may be issued.

[0095] This system will notify healthcare workers if any of the sensors malfunction, but it also means that small errors or discrepancies can be ignored without triggering an alert.

[0096] Using two different sensors improves the reliability of monitoring one or more vital signs. This is because an error in one sensor will be detected if it differs significantly from the value measured by the other sensor. If only one sensor is used, it is impossible to determine whether the sensor is displaying correct results without manually assessing the airway.

[0097] This method may include monitoring the rate of change of vital sign measurements, for example, their first derivative with respect to time. This method may include issuing an alert if the rate of change of vital sign measurements with respect to time (including positive and negative values ​​of the rate of change) is outside a predetermined tolerance range, or exceeds a predetermined limit for each predetermined period. For pulse rate and respiratory rate, the predetermined range may be from negative to positive values ​​of the rate of change. That is, an alert is triggered if both the decrease or increase in vital signs is outside the predetermined range. For blood oxygen saturation, since only a decrease may be a concern, an alert may be issued for a negative rate of change with an absolute value (modulus) greater than a predetermined limit for a period longer than a predetermined period.

[0098] The timer can be started when the rate of change of vital sign measurements falls outside a predetermined tolerance range or exceeds a predetermined limit.

[0099] For example, an alert may be issued if the patient's respiratory rate changes by more than ±30% (or, optionally, if it remains outside this range for 10 minutes).

[0100] For example, an alert may be issued if the patient's pulse rate changes by more than ±40% (or, optionally, if it remains outside this range for 10 minutes).

[0101] For example, an alert may be issued if a patient's blood oxygen saturation drops below 5% (or, optionally, if this limit is exceeded for 10 minutes).

[0102] This method may include monitoring for reduced or lost airway patency. If one or more instances of snoring, wheezing, or rattling are detected, a timer may be started, and an alert may be issued if the snoring, wheezing, or rattling continues for a predetermined period of time.

[0103] If the airway is completely obstructed, a decrease in airway patency can be determined by detecting a drop in respiratory rate to zero. When the respiratory rate drops to zero, a timer starts, and an alert may be issued after a set time (usually about 20 seconds).

[0104] This method may include setting one or more customized tolerances for one or more vital signs, the rate of change of vital signs, the divergence of vital signs measured by both sensors, or the respective time periods for each of these. These may only be set by users with a certain level of authority and may not be set by, for example, healthcare professionals themselves.

[0105] The method according to the second embodiment may further comprise any of the features relating to the first embodiment. [Brief explanation of the drawing]

[0106] Here, certain preferred embodiments will be described in more detail by example only, with reference to the accompanying drawings shown below.

[0107] [Figure 1] Figure 1 is a schematic diagram of a monitoring device consisting of two sensors. [Figure 2] Figure 2 is a perspective view of a monitoring device including a display. [Figure 3] Figure 3 shows the monitoring device attached to the patient. [Figure 4A] Figure 4A shows the adhesive pads for attaching the monitoring device. [Figure 4B] Figure 4B shows the adhesive pad attached to the back of the monitoring device. [Figure 5] Figure 5 shows a schematic diagram of a monitoring device consisting of two sensors that interact with a remote server. [Figure 6] Figure 6 shows how to use the monitoring device. [Modes for carrying out the invention]

[0108] Figure 1 shows a monitoring device 1 used to monitor a patient's vital signs, which continuously monitors the patient's respiratory rate, pulse rate, blood oxygen saturation, and airway patency.

[0109] The monitoring device consists of a first sensor 10 and a second sensor 20, both of which interact with a processor 100. The processor 100 can interpret the readings from the first sensor 10 and the second sensor 20 and store the results in a storage means 50. The storage means 50 also stores a predefined range for each vital sign measurement, an acceptable range / limit for the rate of change of the vital sign measurement, the amount by which the measurements of the same vital sign from two different sensors may diverge, and the time to which each of these applies.

[0110] The first sensor 10 is an optical sensor, and in this case it is a reflected pulse oximeter sensor.

[0111] As is technically known, the reflective pulse oximeter 10 operates on the principle that oxygen-rich blood absorbs light of different wavelengths than oxygen-poor blood, and can optically measure the oxygen saturation in the blood. To measure blood oxygen saturation, the optical sensor measures the reflectance of light of two or more wavelengths. The first wavelength is the wavelength at which oxygenated and deoxygenated hemoglobin absorb light the same, and the second wavelength is the wavelength at which there is a large difference in light absorption between oxygenated and deoxygenated hemoglobin.

[0112] The pulse rate can also be measured using a reflective pulse oximeter 10. Measuring the reflectance of a single wavelength of light is sufficient to determine the pulse rate. When the heart beats, blood pulsates through the arteries at the same frequency as the heartbeat. This pulsation essentially means that the volume of blood in the arteries is changing. This change in volume changes the amount of light absorbed by the blood, i.e., the amount of light reflected. Therefore, the pulse rate can be estimated by measuring the time-dependent variation of the reflected light.

[0113] Furthermore, since respiratory activity affects the photoplethysmography waveform obtained from the reflective pulse oximeter, it is also possible to extract respiratory rate information from the reflective pulse oximeter. Small changes in this waveform are analyzed by processor 100, and machine learning algorithms can be used to determine the respiratory rate. It will be understood that various other types of signal processing means can be used to determine the respiratory rate. For example, advanced filtering techniques perform transformations that allow for the decomposition of signals as well as neural networks. Details are disclosed in "Extraction of Respiratory Rate Information from Wearable Reflective Pulse Oximeter Sensor," WS. Johnston, Y. Mendelson, Department of Biomedical Engineering and the Bioengineering Institute, Worcester Polytechnic Institute, September 2004.

[0114] To enable the reflective pulse oximeter to perform the necessary measurements, the monitoring device consists of two LEDs (not shown) configured to emit light in different wavelength ranges. The first LED emits light with a wavelength peak at 805 nm, and the second LED emits light with a wavelength peak at 660 nm.

[0115] The second sensor 20 consists of an acoustic sensor, which is either a microphone or a piezoelectric sensor. The acoustic sensor 20 can monitor the airway and provide respiratory rate and pulse rate values, which can be used as a second estimate for comparison with the same measurements from the optical sensor 10. The acoustic sensor 20 also provides an assessment of airway patency, such as whether the airway is healthy and not obstructed, partially obstructed, or completely obstructed.

[0116] Breath sounds when the airway is partially obstructed differ from those when the airway is open. When airway patency is reduced, the normal whispering sound of air passing through the airway becomes quieter, and other sounds such as wheezing, rattling, and snoring may be heard. Therefore, relatively loud sounds (compared to normal breathing sounds), or repeated snoring, wheezing, or rattling may indicate that the airway is affected.

[0117] If the airway is completely obstructed, a decrease in respiratory rate to zero indicates loss of airway patency.

[0118] The processor 100 consists of a data acquisition module, a signal processing module, and a data analysis module.

[0119] The data acquisition module receives signals from the optical sensor 10 and the acoustic sensor 20.

[0120] The signal processing module then filters the digital signal and removes noise. The processed signal is then transferred to the data analysis module.

[0121] The data analysis module of the processor 100 can analyze the measurements from each sensor and provide not only respiratory rate and pulse rate values ​​from both the first and second sensors 10 and 20, but also blood oxygen saturation from the optical sensor 10 and airway patency from the acoustic sensor 20.

[0122] The processor 100 can then display data for the caregiver to view on the display 5 of the monitoring device 1, and can also store the measurement data in the integrated storage means 50 within the monitoring device 1.

[0123] Perspective views of the monitoring device 1 are shown in Figures 2 to 4. As shown in Figure 2, the monitoring device 1 includes a display 5 that displays readings from the first sensor 10 and the second sensor 20. The display 5 shows the respiratory rate measured by both the first sensor 10 and the second sensor 20.

[0124] The acoustic sensor reading 200 of the respiratory rate is determined by the processor 100 using the acoustic sensor 20, as described above. On the display, the optical sensor reading 300 of the respiratory rate is provided adjacent to the acoustic sensor reading 200 and is determined by the processor 100 using the optical sensor 10.

[0125] Display 5 also provides a measurement of blood oxygen saturation 400, which is determined by the processor 100 using the optical sensor 10 as described above. Display 5 can also display the pulse rate 500, which can be determined by the processor 100 using both the optical sensor 10 and the acoustic sensor 20. Typically, the optical sensor 10 provides the primary reading of the pulse rate 500, and the acoustic sensor 20 provides the secondary estimate (and a cross-check is performed if the optical sensor 10 malfunctions).

[0126] Monitoring device 1 consists of an auditory alarm 120 and a visual indicator light 140 for alerting caregivers. The auditory alarm 120 and visual indicator light 140 can be used for a variety of different alerts, such as indicating that the device has been calibrated, that the patient's vital signs are outside a predefined tolerance range, that the rate of change in vital signs is outside a predefined tolerance range, or that the measurements from each sensor are significantly different (the deviation exceeds a predefined threshold). The auditory alarm 120 can be deactivated in certain situations, such as in a military environment.

[0127] If any alert occurs, the processor stores the information about the alert and the time in the integrated storage means 50 within the monitoring device 1.

[0128] Additionally, when the battery level of monitoring device 1 becomes low, the auditory alarm 120 or the visual indicator light 140 will illuminate.

[0129] Figure 3 shows the monitoring device 1 attached to the patient's neck 190. By attaching it to the neck, the monitoring device 1 can be easily attached to the patient, and respiratory rate, pulse rate, blood oxygen saturation, and airway patency can be continuously monitored. Furthermore, by positioning the monitoring device 1 on the neck 190, more accurate and timely measurements are possible than with conventional monitoring devices.

[0130] As shown in Figures 4A and 4B, the monitoring device 1 is attached to the neck 190 using a disposable adhesive pad 180. The pad 180 is provided with a removable protective cover 185, which, when removed, exposes the adhesive surface, allowing the monitoring device 1 to be placed on the patient's neck 190.

[0131] In addition to disposable adhesive pads 180, the monitoring device may also be equipped with non-constricting straps or bands 165 that attach to mounting points 160 on both sides of the monitoring device 1. While the monitoring device 1 is typically attached using only the adhesive pads 180, the straps 165 can be used to secure the monitoring device 1 if the adhesive pads 180 are insufficient. The straps 165 can also be used in situations where the patient is being transported or where treatment is required in a way that could cause the monitoring device 1 to fall from the neck 190.

[0132] The monitoring device 1 can be removed by pulling the adhesive pad 180 away from the neck 190, similar to a bandage. After that, the surface of the monitoring device 1 is cleaned, a new adhesive pad 180 is attached, and the monitoring device 1 is ready for reuse.

[0133] Figure 5 shows a further schematic diagram of the monitoring device 1, which can interact with a remote storage server 30 and / or an external device 40. Measurements and alerts recorded by the processor 100 are transferred not only to the integrated storage means 50 but also to the remote storage server 30 via a wireless network interface. Multiple monitoring devices 1 can be connected to the remote storage server 30, making it particularly useful for healthcare professionals who monitor multiple patients simultaneously.

[0134] The monitoring device 1 further includes a Bluetooth interface 60 that enables communication with external devices 40 such as mobile phones or computers. The external devices 40 can be used to monitor measurements from the monitoring device 1, and alerts issued by the processor 100 can be issued by the external devices 40.

[0135] Furthermore, the external device 40 can also control the monitoring device 1 by customizing predefined tolerance ranges for the patient's vital signs, predefined tolerance ranges for the rate of change of vital signs, and thresholds that allow for divergence in the vital sign measurements taken by both sensors.

[0136] Furthermore, the external device 40 can monitor the battery life of the monitoring device 1 and issue an alarm accordingly.

[0137] The external device 40 can connect to multiple monitoring devices 1 simultaneously. Measurements and alerts recorded by the processor can be sent directly to the external device 40 via the Bluetooth interface 60.

[0138] The external device 40 can also connect to the remote storage server 30 via a wireless network interface and access data from multiple monitoring devices 1 recorded by the processor 100. This allows for simultaneous monitoring of results from multiple monitoring devices 1.

[0139] Figure 6 shows how to monitor a patient's airway using monitoring device 1. In step 610, the device is non-invasively positioned around the patient's neck 190 using the adhesive pad 180 and, if necessary, the strap 165.

[0140] Once the device is activated, it performs self-calibration in step 620 (for example, by comparing the sensor signals to an internal or external reference and adjusting as necessary), and the processor 100 begins processing signals from the first sensor 10 and the second sensor 20. The monitoring device 1 issues an alert when the signals to the processor 100 are appropriate, and automatic monitoring of the patient's vital signs begins. The alert is provided by either an auditory alarm 120 or a visual indicator light 140.

[0141] Monitoring device 1 continuously monitors vital signs (step 630) and displays measured values ​​of 200, 300, 400, and 500 on the display so that healthcare professionals can review them without the need for constant monitoring and manual reassessment of the patient's airway, respiratory rate, pulse rate, and blood oxygen saturation.

[0142] The processor 100 continuously processes signals from the first sensor 10 and the second sensor 20. The data is stored in the integrated storage means 50 and transmitted to an external device 40 and / or a remote storage server 30 via a wireless network interface. The data can be monitored by viewing the display 5 directly or by viewing the data on an external device 40 such as a personal computer, tablet, or mobile phone. The latter is useful, for example, when multiple patients are being monitored in multiple locations.

[0143] In step 640, the processor 100 continuously monitors the vital signs and determines whether they are within their respective predefined ranges. If they are within the predefined ranges, the processor 100 continues to monitor the vital signs as usual.

[0144] If one or more of the measurements 200, 300, 400, and 500 monitored by the first and second sensors 10 and 20 are outside the predefined range, this may indicate that the patient's airway is obstructed or that breathing has stopped. If one or more vital signs are outside the predefined range, the timer is started (step 642). In step 644, it is determined whether the vital signs return to the acceptable range within a pre-set time limit. If the vital signs do not return to the acceptable range within the pre-set time limit, the processor in step 646 initiates an alert via either or both an auditory alarm 120 or a visual indicator light 140. The choice of alert method depends on the environment. For example, in military applications, auditory alerts may be undesirable and can be disabled. An external device 40 may also issue an alert. If the vital signs return to the acceptable range within the set time limit, the timer is reset to 0 (step 648).

[0145] An alert is issued if blood oxygen saturation exceeds the range of 90% to 100% and does not return to this range within 15 seconds. An alert is issued if pulse rate exceeds 50 to 120 beats / minute and does not return to this acceptable range within 15 seconds. An alert is issued if respiratory rate exceeds the range of 8 to 27 breaths / minute and does not return to this range within 15 seconds.

[0146] In step 660, the processor 100 also continuously monitors whether there is any discrepancy between the values ​​measured by the first sensor 10 and the second sensor 20 for the same vital sign (i.e., it can compare the pulse rate measured by the first sensor 10 and the second sensor 20, and it can compare the respiratory rate measured by the first sensor 10 and the second sensor 20). Under normal operation, the respiratory rate and pulse rate values ​​measured by the two sensors should be the same (or within a predetermined range) to indicate that both sensors are functioning correctly.

[0147] If the respiratory rate and pulse rate values ​​recorded by the first sensor 10 and the second sensor 20 are different, it may indicate an error related to one of the sensors. In step 662, the processor 100 determines whether the difference between the measurements from the first and second sensors (pulse rate and respiratory rate) is below a predefined threshold. If so, the monitoring device is permitted to continue operating. The predefined threshold can be pre-programmed into the device or customized using an external device 40 via the Bluetooth interface 60 (by a high-level authorized user, not necessarily owned by a healthcare professional).

[0148] When the difference in measurements from the first and second sensors 10 and 20 exceeds a preset threshold, the timer is activated (step 664), and it is determined whether the divergence of vital signs recorded by the first sensor 10 and the second sensor 20 returns to below the threshold within a preset time limit (step 666). If the divergence of vital signs recorded by the first sensor 10 and the second sensor 20 does not return to below the threshold within a preset time limit, in step 668, an alert is issued using either the auditory alarm 120 or the visual indicator light 140. This notifies a nearby caregiver that the monitoring device 1 is malfunctioning and allows for replacement. If the decrease in divergence falls below the threshold within a preset time limit, the timer is reset to 0 (step 670).

[0149] The acceptable divergence in respiratory rate is 3 breaths per minute. If the measurements from the first sensor 10 and the second sensor 20 diverge beyond this limit, the timer starts. If the divergence does not fall below the threshold within one minute, an alert is issued.

[0150] The acceptable divergence of the pulse rate is 12 beats / minute. If the measurements from the first sensor 10 and the second sensor 20 diverge beyond this limit, the timer starts. If the divergence does not fall below the threshold within 30 seconds, an alert is issued.

[0151] The method further includes step 680 of monitoring the rate of change over time of one or more vital signs recorded by a sensor. One or more vital signs must remain at a nearly constant level, and the rate of change of each must be within their respective predetermined ranges.

[0152] In step 682, the processor 100 determines whether the rate of change of each vital sign (including positive and negative values ​​of the rate of change) is within a predetermined tolerance range or exceeds a predetermined limit. If one or more vital sign rates of change are outside a predetermined tolerance range or exceed a predetermined limit, the timer is started (step 684). In step 686, it is determined whether one or more vital sign rates of change will return to a predetermined tolerance range / limit value within a predetermined time. If not, an alert is issued in step 688. Otherwise, the timer is reset to 0 (step 690).

[0153] An alert is issued if the patient's respiratory rate changes by more than ±30% (and remains outside this range for 10 minutes).

[0154] An alert is issued if the patient's pulse rate changes by more than ±40% (and remains outside this range for 10 minutes).

[0155] An alert is issued if the patient's blood oxygen saturation drops below 5% (and if this limit is exceeded for 10 minutes).

[0156] This method also includes detecting reduced or lost airway patency. A timer is activated when one or more of the following are detected: snoring, wheezing, or rattling. If the snoring, wheezing, or rattling continues for a predetermined time (5 to 10 minutes), an alert may be issued. If the snoring, wheezing, or rattling stops within the predetermined time (breathing returns to normal), the timer is reset to 0.

[0157] If the airway is completely obstructed, the device detects a drop in respiratory rate to zero to determine reduced airway patency. When the respiratory rate reaches zero, a timer starts, and an alert is issued after 20 seconds.

[0158] The method described above using monitoring device 1 provides a more definitive and earlier warning of respiratory failure.

[0159] Monitoring device 1 has many applications in hospitals and emergency medicine. In accidents with multiple casualties, triage, treatment, and frequent patient checks are needed simultaneously both at the accident scene and during transport. Monitoring device 1 continuously monitors the patient's airway, respiratory rate, pulse rate, and blood oxygen saturation, allowing nearby caregivers to attend to other tasks or the patient. Because monitoring device 1 is compact, it can be used to monitor patients while they are being transported to the hospital, moving within the hospital, and especially when patients are being sedated.

[0160] Emergency medical technicians (EMTs) and other paramedics can use Monitoring Device 1 while simultaneously performing many other tasks. Attaching Monitoring Device 1 requires minimal time for paramedics to immediately begin other emergency work. Furthermore, Monitoring Device 1 triggers alerts as needed, eliminating the need for paramedics to constantly manually reassess the patient's airway.

[0161] In emergency situations, hospitals may become overcrowded, and temporary field hospitals that lack the same level of equipment as permanent hospitals may be needed. In such situations, monitoring device 1 can be used to monitor a large number of patients simultaneously with relative ease.

[0162] Monitoring device 1 does not require a specialized care worker, so it can also be used for home monitoring.

Claims

1. A monitoring device configured to be detachably attached to the neck of a patient, An optical unit equipped with an optical sensor that monitors measurements of one or more vital signs, including at least one of pulse rate and respiratory rate, An acoustic unit equipped with an acoustic sensor that monitors one or more vital signs, including at least one of pulse rate and respiratory rate, A display that shows measurements of one or more vital signs, A monitoring device including, The first measurement of the vital sign measured by the optical sensor is compared with the second measurement of the same vital sign measured by the acoustic sensor. If the measured values ​​of one or more vital signs measured by the optical unit and the acoustic unit show a difference exceeding a threshold for a period exceeding a preset time limit, an alert is issued. Monitoring device.

2. The monitoring device is continuous The monitoring device according to claim 1, configured to determine whether the measured values ​​of one or more vital signs are within or outside a predetermined range for each of the one or more vital signs.

3. The monitoring device is continuous It is configured to monitor the rate of change of one or more vital sign measurements, and The system is configured to determine whether the rate of change of one or more vital signs falls within or outside a predetermined range. The monitoring device according to claim 1 or 2.

4. The monitoring device is continuous The monitoring device according to claim 2, configured to issue an alert if one or more vital signs are outside their respective predefined ranges for a period exceeding their respective predefined time limits.

5. The monitoring device is continuous The monitoring device according to claim 3, configured to issue an alert if the rate of change of one or more vital signs exceeds a predetermined time limit for each and is outside a predetermined range for each and a half period of time.

6. The monitoring device according to claim 4 or 5, wherein the alert is an auditory alert, and the monitoring device includes a speaker that outputs an auditory alert.

7. The monitoring device according to any one of claims 4 to 6, wherein the alert is a visual alert, and the monitoring device includes a display screen and / or a visible light source for outputting the visual alert.

8. A monitoring device according to any one of claims 4 to 7, comprising an integrated storage means configured to store a history of alerts.

9. The monitoring device is continuous Includes a processor that analyzes one or more vital signs. A monitoring device according to any one of claims 1 to 8.

10. The optical unit includes a reflective pulse oximeter. A monitoring device according to any one of claims 1 to 9.

11. The aforementioned acoustic unit includes a microphone or a piezoelectric sensor. A monitoring device according to any one of claims 1 to 10.

12. Includes an adhesive pad for detachably attaching the monitoring device to the patient's neck, A monitoring device according to any one of claims 1 to 11.

13. Includes a strap for detachably attaching a monitoring device to the patient's neck. A monitoring device according to any one of claims 1 to 12.

14. A monitoring device according to any one of claims 1 to 13, comprising an integrated storage means configured to store a history record of one or more vital signs.

15. moreover, Includes a wireless interface for communicating with external devices and / or remote storage servers, A monitoring device according to any one of claims 1 to 14.

16. The monitoring device is continuous It is configured to send the history of one or more vital signs and / or alerts to a remote storage server. A monitoring device according to any one of claims 1 to 15.

17. A method for monitoring one or more vital signs of a patient using a monitoring device, The monitoring device is continuous An optical unit equipped with an optical sensor for monitoring measurements of one or more vital signs, including at least one of pulse rate and respiratory rate, An acoustic unit equipped with an acoustic sensor for monitoring one or more vital signs, including at least one of pulse rate and respiratory rate, Includes a display that shows one or more vital signs, The aforementioned method, A step of attaching a monitoring device to the patient's neck in a removable manner, A step of monitoring one or more vital signs using an acoustic unit and an optical unit, The steps include comparing a first measurement of a vital sign measured by the optical sensor with a second measurement of the same vital sign measured by the acoustic sensor, The steps include: issuing an alert if one or more vital signs measured by the optical unit and the acoustic unit show a difference exceeding a threshold for a period exceeding a preset time limit; including, method.

18. The method according to claim 17, further comprising the step of determining whether the monitored vital signs are within or outside a predetermined range.

19. If one or more of the aforementioned vital signs remain outside a predetermined range for a period exceeding a predetermined time limit, the method further includes the step of issuing an alert. The alert is an auditory alert and / or a visual alert. The method according to claim 18.

20. The steps include monitoring the rate of change of one or more vital signs measured, A step of determining whether the rate of change of the measured value of one or more vital signs falls within or outside a predetermined range for the rate of change of the measured value of one or more vital signs. A method according to any one of claims 17 to 19, including the method described above.

21. The system includes a step of issuing an alert if the rate of change of one or more vital signs exceeds a predetermined time limit for each of the aforementioned vital signs, and is outside a predetermined range for each of the aforementioned vital signs. The method according to claim 20.

22. The procedure includes the step of monitoring one or more of the following using an optical sensor: blood oxygen saturation, pulse rate, and respiratory rate. The method according to any one of claims 17 to 21.

23. The procedure includes a step of monitoring one or more of the following using an acoustic sensor: respiratory rate, pulse rate, and airway patency. The method according to any one of claims 17 to 22.

24. The step includes using the monitoring device described in any one of claims 1 to 16, The method according to any one of claims 17 to 23.

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