Oxygen saturation measuring device and oxygen saturation measuring method

Abstract

This oxygen saturation measuring device is provided with: a band wound around the wrist of a subject; a first sensor unit that is attached to the band and that acquires a pulse wave signal of an artery of the wrist and measures the oxygen saturation of the artery of the wrist on the basis of the acquired pulse wave signal; and a notification unit that, when the oxygen saturation measured by the first sensor unit satisfies a preset condition, notifies the subject of a warning indicating the likelihood that the respiratory organ is abnormal.

Description

Technical Field

[0001] The present disclosure relates to an oxygen saturation measurement device and an oxygen saturation measurement method. Background Art

[0002] Conventionally, as a device for measuring oxygen saturation (SpO2) in arterial blood, a touch screen interface with a pulse oximeter is disclosed as shown in Japanese Patent Laid-Open No. 2010-246894. In Japanese Patent Laid-Open No. 2010-246894, the oxygen saturation in arterial blood at the fingertips can be measured by bringing the fingertips of the subject into contact with the touch screen.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2010-246894 Summary of the invention

[0004] Technical problem to be solved by the invention

[0005] Generally speaking, when the oxygen saturation deviates from the specified range, it can be inferred that the state of the subject's respiratory organs is abnormal. For example, when the oxygen saturation is within a preset range of about 95% to about 99%, it can be determined that the state of the subject's respiratory organs is normal. On the other hand, when the oxygen saturation is outside the set range, such as 94%, it can be determined that the state of the subject's respiratory organs is abnormal.

[0006] Here, if the oxygen saturation of the measured person can be measured continuously over time, the temporal change of the measured value can be obtained. By utilizing the temporal change of the measured value, the state of the respiratory organ of the measured person can be diagnosed more comprehensively, and as a result, the state of the ventilator can be improved. In order to measure the oxygen saturation continuously over time, it is necessary to wear the oxygen saturation measuring device continuously over time at a predetermined position on the body of the measured person.

[0007] However, when the contact part of the person being measured is a fingertip as in Japanese Patent Laid-Open No. 2010-246894, the oxygen saturation measuring device is continuously worn on the fingertip. Therefore, it is easy to cause obstacles to daily life actions such as holding a pen or operating an electronic terminal with fingers, eating or excreting. In other words, when measuring oxygen saturation at the fingertip, it is difficult to measure continuously in time.

[0008] The present disclosure has been made in view of the above-mentioned situation, and provides an oxygen saturation measuring device and an oxygen saturation measuring method that allow a subject to easily measure oxygen saturation continuously over time and that can improve the state of the respiratory organs.

[0009] Technical solutions to solve problems

[0010] The first mode of the present disclosure relates to an oxygen saturation measuring device comprising: a belt wound around a wrist of a person to be measured; a first sensor unit mounted on the belt and used to obtain a pulse wave signal of an artery at the wrist and measure the oxygen saturation of the artery at the wrist based on the obtained pulse wave signal; and a notification unit that notifies the person to be measured of a warning indicating the possibility of abnormality in the respiratory organ when the oxygen saturation measured by the first sensor unit satisfies a preset condition.

[0011] According to the first embodiment, the belt is wound around the wrist of the person being measured, and the pulse wave signal of the artery of the wrist is acquired by the first sensor unit attached to the belt. In addition, the oxygen saturation of the artery of the wrist is measured based on the acquired pulse wave signal. That is, since the oxygen saturation is measured at the wrist, it is less likely to cause a state that interferes with the work action or daily life action of the person being measured, compared with the case where the oxygen saturation is measured at the fingertips, and it is easy to measure the oxygen saturation continuously in time.

[0012] In addition, when the measured wrist artery oxygen saturation satisfies a preset condition, a warning indicating the possibility of respiratory abnormality is notified to the subject. The warning encourages the subject to take actions such as consulting a doctor, thereby improving the respiratory condition.

[0013] An oxygen saturation level measurement device according to a second aspect is the oxygen saturation level measurement device according to the first aspect, wherein the first sensor unit is attached to the inner side of the belt.

[0014] According to the second aspect, since the first sensor unit is attached to the inner side of the belt, that is, the side of the belt that contacts the wrist, it is easy to measure, for example, the radial artery close to the inner surface of the wrist.

[0015] The oxygen saturation measurement device according to a third aspect is the first aspect or the second aspect, wherein when the measured oxygen saturation does not reach a preset reference value, the notification unit notifies the subject as a warning to urge the subject to measure the oxygen saturation at the fingertip position.

[0016] According to the third aspect, when the measured oxygen saturation does not reach the preset reference value, the subject is notified as a warning to urge the subject to measure the oxygen saturation at the fingertip position. Therefore, the measurement of oxygen saturation with further improved measurement accuracy can be promoted.

[0017] An oxygen saturation measurement device according to a fourth aspect is any one of the first to third aspects, further comprising a second sensor unit, the second sensor unit being attached to the belt and configured to measure the oxygen saturation of a fingertip artery of a subject.

[0018] According to the fourth aspect, a second sensor unit is further provided, which is mounted on the belt and is used to measure the oxygen saturation of the artery at the fingertip. Therefore, it is possible to use a single oxygen saturation measurement device to achieve both continuous measurement of oxygen saturation at the wrist position and measurement of oxygen saturation at the fingertip position with higher measurement accuracy. That is, it is not necessary to separately prepare an oxygen saturation measurement device for measuring the oxygen saturation of the artery at the fingertip.

[0019] Furthermore, an oxygen saturation level measurement device according to a fifth aspect is the oxygen saturation level measurement device according to the fourth aspect, wherein the second sensor unit is attached to the outside of the belt.

[0020] According to the fifth aspect, the second sensor unit is mounted on the outside of the belt, that is, on the side of the belt that does not contact the wrist and is easily visible to the person being measured. Therefore, the person being measured can operate the second sensor unit more easily than when the second sensor unit is mounted on the inside of the belt.

[0021] The sixth mode of the present disclosure involves an oxygen saturation measuring device comprising: a belt, which is wound around the wrist of the person being measured; a first sensor unit, which is mounted on the belt, obtains a pulse wave signal of an artery at the wrist, and is used to measure the oxygen saturation of the artery at the wrist based on the obtained pulse wave signal; a notification unit, when the oxygen saturation measured by the first sensor unit meets a preset condition, the notification unit notifies the person being measured of a warning indicating the possibility of abnormal respiratory organs; a second sensor unit, which is mounted on the belt and is used to measure the oxygen saturation of the artery at the fingertips of the person being measured; and a display unit, which displays the oxygen saturation measured by the second sensor unit.

[0022] According to the sixth aspect, one oxygen saturation measurement device can be used to achieve both continuous measurement of oxygen saturation at the wrist and measurement of oxygen saturation at the fingertips with higher measurement accuracy.

[0023] Furthermore, an oxygen saturation measurement device according to a seventh aspect is the oxygen saturation measurement device according to the sixth aspect, wherein the notification unit and the display unit are integrated.

[0024] According to the above configuration, the overall size of the oxygen saturation measurement device can be reduced compared to a case where the notification portion and the display portion are separate, and thus the oxygen saturation measurement device can be configured to be compact.

[0025] The eighth aspect of the present disclosure relates to an oxygen saturation measurement method including: acquiring a pulse wave signal of an artery at a wrist of a subject; measuring the oxygen saturation of the artery based on the acquired pulse wave signal; and notifying the subject of a warning when the measured oxygen saturation satisfies a preset condition.

[0026] According to the eighth aspect, similarly to the first aspect, it is easy to measure the oxygen saturation level continuously in terms of time, and the state of the respiratory organs can be improved.

[0027] (Effects of the Invention)

[0028] According to the oxygen saturation measurement device and the oxygen saturation measurement method according to the present disclosure, the oxygen saturation of the subject can be easily measured continuously over time, and the state of the respiratory organs can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a perspective view illustrating an oxygen saturation measurement device according to an embodiment of the present disclosure.

[0030] Figure 2 It is a cross-sectional view illustrating the oxygen saturation measurement device according to the present embodiment.

[0031] Figure 3 It is a plan view illustrating a sensor unit of the oxygen saturation measurement device according to the present embodiment.

[0032] Figure 4 Figure 3 The 4-4 line section view in.

[0033] Figure 5 It is a graph explaining the change of the oxygen saturation value of the fingertip artery measured continuously over time and the change of the oxygen saturation value of the wrist artery measured continuously over time.

[0034] Figure 6 1 is a flowchart for explaining the oxygen saturation measurement method using the oxygen saturation measurement device according to the present embodiment.

[0035] Figure 7 This is a perspective view for explaining a state in which the oxygen saturation level of a fingertip artery is measured using the second sensor unit in the oxygen saturation level measurement method according to the present embodiment.

[0036] Figure 8 This is a flowchart for explaining a state in which the oxygen saturation level of a fingertip artery is measured using the second sensor unit in the oxygen saturation level measurement method according to the modification. DETAILED DESCRIPTION

[0037] The present embodiment is described below. In the description of the following drawings, the same or similar parts are marked with the same reference numerals or similar reference numerals. However, the drawings are schematic, and the relationship between thickness and plane size, the ratio of thickness of each device or each component, etc. are different from reality. Therefore, the specific thickness or size should be determined with reference to the following description. In addition, the drawings also include parts with different dimensional relationships or ratios. In addition, unless otherwise specified in the specification, the number of each component element disclosed in the present invention is not limited to one, and multiple components may exist.

[0038] <Oxygen saturation measurement device>

[0039] Reference Figures 1 to 5 The structure of the oxygen saturation measurement device 10 according to this embodiment will be described. Figure 1 As shown, the oxygen saturation measurement device 10 according to the present embodiment includes a belt 12 , a first sensor unit 11 , a notification unit 26 , and a second sensor unit 21 .

[0040] (bring)

[0041] like Figure 2 As shown, the belt 12 is wound around the wrist of the person being measured. The material of the belt 12 is any material such as resin, cloth, metal, etc. In addition, the belt 12 is provided with a buckle for adjusting and fixing the length when wound around the wrist.

[0042] (First sensor unit)

[0043] like Figure 1 and Figure 2 As shown, the first sensor unit 11 is mounted on the inner side of the belt 12, that is, the side of the belt 12 that contacts the wrist. In addition, in the present disclosure, the mounting position of the first sensor unit is not limited to the inner side of the belt 12, and may be the outer side of the belt 12. The first sensor unit 11 acquires a pulse wave signal of the artery of the wrist, and measures the oxygen saturation of the artery of the wrist based on the acquired pulse wave signal.

[0044] Specifically, the first sensor unit 11 of the present embodiment is composed of a base 14, a contact portion 16, a light emitting element, a light receiving element, and a computing unit 18. The computing unit 18 is accommodated inside the housing 25. In addition, in the present disclosure, the first sensor unit 11 can be arbitrarily configured as long as it can obtain a pulse wave signal of an artery of the wrist.

[0045] exist Figure 2 In the oxygen saturation measurement device 10 illustrated in FIG. 1 , a first light receiving element PD1, a second light receiving element PD2, a third light receiving element PD3, a fourth light receiving element PD4, and a fifth light receiving element PD5 are provided as light receiving elements. Figure 2 The inside of the wrist in FIG. 2 is illustrated with the radius 20 , the radial styloid process 20A, the radial flexor carpi radialis tendon 22 , and the radial artery 24 .

[0046] (Base)

[0047] The base 14 is provided on the inner surface of the belt 12. Specifically, in the present embodiment, the base 14 can be fixed to the belt 12 by, for example, bonding. However, the fixing method is not limited to bonding, and a plate-like member for fixing may be interposed between the base 14 and the belt 12, and the circuit substrate may be fixed to the plate-like member by screwing or the like.

[0048] The base 14 has a flat joint surface 14A between the belt 12 and the contact portion 16. In the present embodiment, both the light emitting element and the light receiving element are joined to the joint surface 14A of the base 14. In the present disclosure, at least one of the light emitting element and the light receiving element only needs to be joined to the joint surface 14A.

[0049] In addition, in the present disclosure, the base 14 may be the circuit substrate itself on which the light emitting element and the light receiving element are mounted, or may be a combination of the circuit substrate and a plate-shaped member for fixing, or a combination of the circuit substrate and a buffer member, etc. That is, the base 14 of the present disclosure only needs to have a bonding surface 14A for bonding at least one of the light emitting element and the light receiving element.

[0050] like Figure 3 As shown in FIG. 1 , a light emitting element and a light receiving element are arranged on a bonding surface 14A of the base 14. In addition, illustration of a circuit board on which the light emitting element and the light receiving element are mounted is omitted.

[0051] (Light-emitting element)

[0052] The light emitting element is, for example, an electronic component such as a light emitting diode (LED). The light emitting element is arranged at a predetermined position relative to the contact portion 16, and irradiates light to the artery of the wrist. In the present embodiment, as light emitting elements, a first light emitting element LED1, a second light emitting element LED2, and a third light emitting element LED3 are provided. The first light emitting element LED1, the second light emitting element LED2, and the third light emitting element LED3 are arranged separately from each other and arranged along the circumference of the wrist. In addition, in the present disclosure, the number of light emitting elements is any number greater than one.

[0053] like Figure 3 As shown, the first light emitting element LED1, the second light emitting element LED2, and the third light emitting element LED3 each have a group of light sources including one or more red light sources RED and one or more infrared light sources IR. That is, in this embodiment, two types of light are irradiated from one light emitting element. Moreover, the two types of reflected light received by one light receiving element are used to measure the oxygen saturation. In addition, in the present disclosure, the type of light source is not limited to two types, and can be one type, or can be three or more types.

[0054] (Principle of oxygen saturation measurement)

[0055] Here, the principle of measuring oxygen saturation in this embodiment using two types of irradiation light and two types of reflected light is described. Specifically, for example, red light in the wavelength region of about 620nm to about 700nm has a characteristic that the absorbance changes greatly depending on the presence or absence of oxygen bound to hemoglobin. On the other hand, near-infrared light in the wavelength region of about 850nm to about 960nm has a characteristic that the absorbance does not change greatly depending on the presence or absence of oxygen bound to hemoglobin.

[0056] Therefore, the intensity change of the pulse wave signal of the reflected light of the red light is monitored over time, and the variable component (in other words, AC) and the fixed component (in other words, DC) of the pulse wave signal contained in the monitored pulse wave signal are calculated. In addition, by dividing the variable component by the fixed component (AC / DC), the perfusion index (PI) value of the red light is calculated as PI. RED In addition, similarly to the case of red light, the PI value (PI) of the reflected light of the near-infrared light is calculated by monitoring the intensity change of the pulse wave signal of the reflected light of the near-infrared light over time. IR ).

[0057] Furthermore, the PI value of red light (PI RED ) and the PI value of near infrared light (PI IR ) ratio (PI RED / PI IR ). Moreover, by calculating the ratio (PI RED / PI IR ) is used in the following formula (1) to calculate the oxygen saturation.

[0058] Oxygen saturation [%] = a × (PI RED / PI IR )+b…Formula (1)

[0059] The coefficients a and b in the formula (1) can be obtained by experiments. In the present disclosure, the method for measuring the oxygen saturation is not limited to this method, and other methods may be used.

[0060] (Light receiving element)

[0061] The light receiving element is, for example, an electronic component such as a photodiode (PD). The light receiving element is arranged at a predetermined position relative to the contact portion 16, and receives reflected light from the artery of the wrist via the contact surface 16A of the contact portion 16. The first light receiving element PD1, the second light receiving element PD2, the third light receiving element PD3, the fourth light receiving element PD4, and the fifth light receiving element PD5 are arranged separately from each other and arranged along the circumference of the wrist. In addition, in the present disclosure, the number of light receiving elements is an arbitrary number greater than one.

[0062] In this embodiment, one or more light-emitting elements and one or more light-receiving elements corresponding to the one or more light-emitting elements constitute a "sensor unit". In the present disclosure, multiple sensor units can be provided. In addition, the number of light-emitting elements and the number of light-receiving elements contained in one "sensor unit" can be set arbitrarily.

[0063] The oxygen saturation measurement device 10 according to the present embodiment is of a reflection type that measures the intensity of a pulse wave signal by reflected light, but the present disclosure is not limited to the reflection type and may be of a transmission type that measures the intensity of a pulse wave signal by transmitted light.

[0064] (shading part)

[0065] like Figure 4 As shown, a light shielding portion 14B is provided between the light emitting element and the light receiving element in the base 14. The light shielding portion 14B prevents the light receiving element from directly receiving light from the light emitting element. In addition, from the viewpoint that the optical path length is shortened and the measurement accuracy can be improved as a result, it is preferred to use the light shielding portion 14B and the interval between the light emitting element and the light receiving element is as close as possible.

[0066] (Contact Department)

[0067] The contact part 16 is mounted on the belt 12. The contact part 16 is translucent with respect to the light irradiated to the artery of the wrist and the reflected light from the artery of the wrist. Specifically, for example, a translucent component such as a lens can be used. Figure 4 The contact portion 16 disposed on the upper side of the light emitting element is, for example, a diffusion lens capable of expanding the irradiation area. In addition, although not shown in the figure, a diffusion agent may be disposed on the upper side of the light emitting element together with or in place of the diffusion lens. Figure 4 The contact portion 16 disposed on the upper side of the light receiving element may be, for example, a condenser lens capable of condensing reflected light.

[0068] The contact portion 16 has a contact surface 16A that protrudes from the band 12 toward the wrist. In the present embodiment, the contact surface 16A has a curved shape. The contact surface 16A contacts the skin of the wrist when measuring the oxygen saturation.

[0069] like Figure 3 and Figure 4 As shown, the contact portion 16 is dome-shaped. In the contact surface 16A corresponding to the outer surface of the dome, Figure 4The central part in the left-right direction (i.e., the extension direction E of the forearm) is flat, and the left and right ends have a certain curvature, thereby smoothly bending without edges. From the perspective of improving the wearability of the measured person, the curvature is preferably 0.167 or more, for example. In addition, although not shown in the figure, similarly, the central part of the contact part 16 in the circumferential direction C of the wrist is flat, and the left and right ends are smoothly bent.

[0070] In addition, in the present disclosure, the contact surface may not have a flat portion, and the contact surface may have a curved shape while having a certain curvature as a whole.

[0071] In addition, in this specification, the "extension direction E of the forearm" overlaps with any one of the extension direction of the radius 20, the extension direction of the ulna, and the extension direction of the artery. In addition, strictly speaking, the "extension direction E of the forearm" is different for each subject. That is, the "extension direction E of the forearm" is not uniquely determined by coordinates in a three-dimensional space, but is determined individually according to the extension direction of the radius 20, the extension direction of the ulna, and the extension direction of the artery of each subject.

[0072] (case)

[0073] The housing 25 is attached to the belt 12 and contacts the outer side of the wrist of the person being measured, that is, the surface on the nail side. The housing 25 may be made of any material such as resin or metal. In the present disclosure, the housing 25 is not essential.

[0074] (Calculation unit)

[0075] In this embodiment, the calculation unit 18 is provided in the housing 25. The calculation unit 18 is connected to the light receiving element. The data of the pulse wave signal of the reflected light is input to the calculation unit 18 from the light receiving element over time.

[0076] The calculation unit 18 is configured as a computer including, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a storage device, an I / O port, etc. The RAM, the storage device, the I / O port, etc. are configured to be able to exchange data with the CPU via an internal bus. The calculation unit 18 measures the oxygen saturation of the radial artery 24 irradiated with light based on the pulse wave signal obtained from the reflected light by a method using a ratio of PI values, etc.

[0077] (Notification Department)

[0078] like Figure 1As shown, the notification unit 26 is disposed on the surface of the housing 25 on the opposite side to the wrist. The notification unit 26 is, for example, an image display device formed of liquid crystal, etc. The notification unit 26 displays the calculation result of the calculation unit 18 to the outside in a manner that the person being measured can visually recognize.

[0079] A storage device for temporarily storing the measurement result may also be provided in the notification unit 26. In addition, in the present disclosure, when the housing 25 is not provided, the operation unit may be configured as a part of the operation device on the contact unit or the base, for example. Similarly, the storage device may also be configured on a component other than the housing such as the contact unit or the base. In the present disclosure, even when the notification unit 26 is not provided on the housing 25, for example, the calculation result of the operation unit 18 can be obtained by using a communication unit connected to the operation unit 18 and capable of communicating with the outside.

[0080] When the oxygen saturation measured by the first sensor unit 11 satisfies a preset condition, the notification unit 26 notifies the subject of a warning indicating the possibility of abnormality of the respiratory organ. Specifically, when the measured oxygen saturation does not reach a preset reference value, the notification unit 26 notifies the subject of a warning to urge the subject to measure the oxygen saturation at the fingertip position.

[0081] (Baseline value)

[0082] In the present embodiment, the reference value is 90% oxygen saturation. When the oxygen saturation is less than 90%, the notification unit 26 notifies the subject as a warning to urge the subject to measure the oxygen saturation at the fingertip position. That is, the reference value of the present embodiment is the lower limit of the oxygen saturation. In addition, the condition of the present embodiment is that the measured oxygen saturation does not reach the lower limit.

[0083] When the reference value is the oxygen saturation level as in the present embodiment, the reference value as the lower limit value for determining whether to issue a warning is preferably set within a range of 90% to 94%. Figure 5 In FIG. 1 , a solid line illustrates a trajectory of data obtained by continuously measuring the oxygen saturation at the fingertips using the first sensor unit 11. A dotted line illustrates a trajectory of data obtained by continuously measuring the oxygen saturation at the wrist using the first sensor unit 11.

[0084] In addition, in the present disclosure, the reference value for determining whether to notify a warning is not limited to the range of 90% to 94%, and can be appropriately changed according to the state of the respiratory organs of the person being measured. For example, in the case of a patient suffering from a specific viral infection, the oxygen saturation may be chronically around 92% to 93%. Therefore, in the present disclosure, as another example of a reference value, the reference value can be set by a combination of an initial value and a correction value indicating the amount of decrease relative to the initial value. The initial value and the correction value can be pre-set for each person being measured according to the state of the respiratory organs of the person being measured.

[0085] Specifically, as the initial value, an average value of oxygen saturation measured within a certain period, such as the most recent month before setting, may be used. For example, when the measured person is a patient suffering from a specific viral infection, the initial value may be set to 92%, but is not limited thereto and may vary depending on the measured person or the state of the measured person's respiratory organs.

[0086] In addition, the correction value can be set empirically based on clinical data or analytical data, etc., which are obtained from a group of subjects having information similar to the personal information of the subject's nationality, gender, age, height, weight, and current respiratory organ status. The correction value can be set to 2%, for example, but is not limited to this and may vary depending on the subject or the respiratory organ status of the subject.

[0087] As described above, when the subject is a patient suffering from a specific viral infection and the initial value is set to, for example, 92% and the correction value is set to 2%, a value of "90%" can be obtained by subtracting the correction value from the initial value. The obtained value of "90%" can be set as a reference value for determining whether to notify a warning in oxygen saturation measurement.

[0088] In addition, the present disclosure evaluated the consistency between the measurement accuracy at the wrist position and the measurement accuracy at the fingertip position by Bland-Altman analysis on five subjects. Specifically, the first sensor unit 11 was used to obtain the temporal changes in the measurement values ​​of the oxygen saturation at the wrist position and the temporal changes in the measurement values ​​of the oxygen saturation at the fingertip position while each subject held their breath.

[0089] In the Bland-Altman analysis, the average value of the oxygen saturation values ​​of the five subjects was calculated, and the spread of positive and negative errors from the calculated average value was calculated within the range of oxygen saturation of 80% to 100%. The spread of errors in the fingertip position measurement was about 3.0%.

[0090] On the other hand, the error diffusion in the wrist position measurement is about 6.0%. That is, it can be seen that the error diffusion in the wrist position measurement is about twice as large as that in the fingertip measurement. In addition, from the analysis results, it can be seen that the measurement error at the wrist position is larger than the measurement error at the fingertip position, especially in the range of oxygen saturation below 90%.

[0091] like Figure 5 As shown, it can be seen that when the oxygen saturation of the reference value is less than 90%, the measurement accuracy of the oxygen saturation when measured at the wrist position is lower than the measurement accuracy when measured at the fingertip position. The perfusion of arterial blood at the fingertip position is greater than the perfusion of arterial blood at the wrist position. Therefore, the accuracy of determining the state of the respiratory organ of the measured person is reduced. On the other hand, when the oxygen saturation of the reference value for determining whether to issue a warning exceeds 94%, the range of the respiratory organ state diagnosed as normal increases, so the number of warnings increases.

[0092] In the present disclosure, the condition for determining whether to notify a warning is not limited to the lower limit of oxygen saturation, and can be set arbitrarily. For example, biological information other than oxygen saturation such as breathing rate and cough frequency can also be used to set the condition. For example, the breathing rate and cough frequency of the person being measured are biological information that can be obtained from the pulse wave signal.

[0093] In addition, for example, arbitrary blood vessel information other than the pulse wave signal, such as sound wave information of the sound of the artery flowing in the blood vessel, may be used to set the condition. For example, in the case of using the sound of the artery flowing, the first sensor unit 11 may have a microphone with a sound pickup function. As the sound wave information, for example, the frequency or amplitude may be used. In addition, the number of coughs may also be obtained from the sound of the artery flowing. The reference value used in the condition setting may be set based on the sound wave information from the sound of the artery flowing.

[0094] In the present embodiment, the warning is image information including text or graphics. In addition, in the present disclosure, the warning is not limited to image information, and may be performed by, for example, lighting or flashing a light of a specific notification color. In addition, the warning may also be sound or vibration.

[0095] (Second sensor unit)

[0096] like Figure 1 and Figure 2As shown, the second sensor unit 21 is mounted on the outside of the belt 12, that is, on the side of the belt 12 that does not contact the wrist and at a position that is easily visually recognized by the person being measured. The second sensor unit 21 measures the oxygen saturation of the artery of the fingertip of the person being measured. The second sensor unit 21 of the present embodiment is composed of a measuring unit 28 and a computing unit 18. The measuring unit 28 has a panel that serves as a touch screen interface. In addition, in the present disclosure, the mounting position of the second sensor unit is not limited to the outside of the belt 12. For example, as long as the malfunction of the touch screen can be prevented by forming a non-powered state to the second sensor unit during contact with the wrist, it can also be mounted on the inside of the belt 12.

[0097] The measuring unit 28 is provided with a light energy source (not shown), and two wavelengths of light for measuring oxygen saturation are irradiated from the light energy source inside the measuring unit 28. When the fingertip of the person being measured is brought into contact with the measuring unit 28, the two wavelengths of light are attenuated respectively. In addition, the measuring unit 28 is provided with a detection unit (not shown) for detecting the attenuated light, and the detection unit is connected to the calculation unit 18. The calculation unit 18 measures the oxygen saturation in the arterial blood of the fingertip based on the attenuated light.

[0098] In addition, in the present disclosure, the second sensor unit can be configured arbitrarily as long as it can measure the oxygen saturation of the artery of the fingertip. For example, the oxygen saturation measurement method in the second sensor unit can be either a reflective type or a transmissive type of measurement light. In addition, the second sensor unit can apply a known touch screen interface technology.

[0099] <Oxygen saturation measurement method>

[0100] Next, refer to Figure 2 , Figure 6 to Figure 7 An example of an oxygen saturation level measuring method using the oxygen saturation level measuring device 10 according to the present embodiment will be described.

[0101] First, if Figure 6 As shown in step S10 in , the subject wraps the belt 12 of the oxygen saturation measuring device 10 around the subject's wrist. The artery of the measuring object is, for example, the radial artery 24. In addition, in the present disclosure, the artery of the measuring object is not limited to the radial artery 24, and may be any other artery. Furthermore, the contact surface 16A is brought into contact with the skin near the radial styloid process 20A on the inner side of the wrist.

[0102] Then, if Figure 2 As shown, the subject places the contact portion 16 inside the depression between the radial styloid process 20A and the radial flexor carpi tendon 22. Next, as shown in step S20, the subject acquires the pulse wave signal of the artery of the subject's wrist using the first sensor unit 11. Then, the oxygen saturation of the artery is measured based on the acquired pulse wave signal.

[0103] Specifically, from the light emitting element to the Figure 2 The radial artery 24 on the lower side of the depression in the radial artery 24 is irradiated with light. Then, the reflected light from the radial artery 24 is received by the light receiving element. Then, the calculation unit 18 measures the oxygen saturation based on the pulse wave signal obtained from the reflected light.

[0104] Next, as shown in step S30, the calculation unit 18 compares the measured oxygen saturation with a preset reference value. When the compared oxygen saturation is greater than the reference value, it is determined that a warning is not required. Then, the process transfers to step S20, and the measurement of oxygen saturation is repeatedly performed. On the other hand, when the compared oxygen saturation does not reach the reference value, as shown in step S40, the calculation unit 18 notifies the person being measured of a warning.

[0105] Here, in the present disclosure, for example, the energization to the second sensor unit 21 can be controlled so that the energization to the second sensor unit 21 is cut off before the warning is notified, and the energization to the second sensor unit 21 is started after the warning is notified. By controlling the energization to the second sensor unit 21, power consumption can be suppressed.

[0106] Next, as shown in step S50, the subject measures the oxygen saturation of the artery of the fingertip using the second sensor unit 21. Specifically, the fingertip is brought into contact with the measuring unit 28 of the second sensor unit 21. The measured value of the oxygen saturation is displayed on the notification unit 26 as a display unit. In addition, in the present disclosure, the display unit that displays the measured value of the oxygen saturation measured by the second sensor unit 21 may be integrated with the notification unit 26 as in the present embodiment, or may be provided separately from the notification unit 26.

[0107] Then, if Figure 6 As shown in step S60 in FIG. 1 , the calculation unit 18 stores the measured value in the storage device. For example, when a doctor or the like performs a diagnosis later, the stored measured value can be displayed on the notification unit 26 to facilitate the diagnosis.

[0108] In addition, in the present disclosure, arbitrary additional data such as the name of the sensor unit used in the measurement or the date and time may be stored in the storage device together with the measured value. In addition, in the present disclosure, the measured value measured by the first sensor unit 11 may be stored in the storage device. In addition, in the present disclosure, for example, the processing of step S20 and thereafter may be repeated after the processing of step S60.

[0109] (Effect)

[0110] According to the first embodiment, the belt 12 is wound around the wrist of the subject, and the pulse wave signal of the artery of the wrist is acquired by the first sensor unit 11 attached to the belt 12. In addition, the oxygen saturation of the artery of the wrist is measured based on the acquired pulse wave signal. That is, since the oxygen saturation is measured at the wrist, it is less likely to cause a state that interferes with the subject's work movements or daily life movements, compared with the case where the oxygen saturation is measured at the fingertips, and it is easy to measure the oxygen saturation measurement device 10 continuously in time.

[0111] In addition, the measured oxygen saturation of the wrist artery is compared with a preset reference value, and when the measured oxygen saturation does not reach the reference value, a warning indicating the possibility of abnormal respiratory organs is notified to the measured person. The warning encourages the measured person to take actions such as consulting a doctor, so that the state of the respiratory organs can be improved as a result.

[0112] In the present embodiment, the first sensor unit 11 is attached to the inner side of the belt 12, that is, the side of the belt 12 that contacts the wrist. Therefore, it is easy to measure the radial artery 24 that is close to the inner surface of the wrist.

[0113] In addition, in this embodiment, when the oxygen saturation is less than 90%, the subject is notified as a warning to urge the subject to measure the oxygen saturation at the fingertip position. Therefore, it is possible to promote the measurement of oxygen saturation with further improved measurement accuracy.

[0114] In addition, the oxygen saturation measurement device 10 according to the present embodiment further includes a second sensor unit 21, which is mounted on the belt 12 and is used to measure the oxygen saturation of the fingertip artery. Therefore, it is possible to achieve both the measurement of the oxygen saturation at the wrist position continuously in time and the measurement of the oxygen saturation at the fingertip position with higher measurement accuracy using a single oxygen saturation measurement device 10. That is, it is not necessary to prepare a separate oxygen saturation measurement device for measuring the oxygen saturation of the fingertip artery.

[0115] In addition, even if a high-precision oxygen saturation measuring device that measures at the fingertips is placed in a place far away from the person being measured, the person being measured does not need to move to get the high-precision oxygen saturation measuring device. Therefore, after receiving the warning, the oxygen saturation of the fingertip artery can be measured quickly. In addition, since the person being measured does not need to move to get the oxygen saturation measuring device, it is easy to establish a habit of measuring oxygen saturation.

[0116] In addition, in the present embodiment, the second sensor unit 21 is mounted on the outside of the belt 12, that is, on the side of the belt 12 that does not contact the wrist and is easily visually recognized by the person being measured. Therefore, compared with the case where the second sensor unit 21 is mounted on the inside of the belt 12, it is easier for the person being measured to operate the second sensor unit 21.

[0117] In addition, in the present embodiment, the notification unit 26 and the display unit are integrated. Therefore, the overall size of the oxygen saturation measurement device can be reduced compared to the case where the notification unit 26 and the display unit are separate. As a result, the oxygen saturation measurement device can be configured compactly.

[0118] Furthermore, according to the oxygen saturation measurement method using the oxygen saturation measurement device 10 according to the present embodiment, the oxygen saturation measurement device 10 can be measured continuously in terms of time, and the state of the respiratory organs can be improved.

[0119] (Variation Example)

[0120] In this embodiment, as a condition for notifying a warning to measure oxygen saturation at the fingertip position, the case where the oxygen saturation measured at the wrist artery of the person being measured does not reach the reference value is described as an example, but the present disclosure is not limited to this. Figure 8 In the embodiment, an oxygen saturation measurement method according to a modified example of notifying a warning according to the breathing state of the subject is illustrated.

[0121] The oxygen saturation measurement method according to the modified example is different from the oxygen saturation measurement method according to the present embodiment in that Figure 6 Step S20 and step S30 in the embodiment include Figure 8 In step S21 and step S31, the respiratory rate is used instead of the oxygen saturation. Figure 6 The corresponding steps are the same, so repeated description is omitted.

[0122] In a modified example, Figure 8 As shown in step S21 in the above, the breathing rate of the subject is detected. The breathing rate can be detected by, for example, acquiring a pulse wave signal of the wrist artery of the subject using the first sensor unit 11 and performing the detection based on the acquired pulse wave signal.

[0123] Next, as shown in step S31, the detected respiratory frequency is compared with the respiratory frequency of a preset reference value. When the compared respiratory frequency is above the reference value, it is determined that a warning is not required. When it is determined that a warning is not required, the process is transferred to step S21, and the measurement of the respiratory frequency is repeatedly performed.

[0124] On the other hand, when the compared respiratory rate does not reach the reference value, as shown in step S40, a warning is notified to the person being measured. The following is the same process as in the present embodiment. In a modified example, even in a state where the oxygen saturation cannot be measured, the respiratory rate can be used to determine the state of the respiratory organ of the person being measured. In the present disclosure, as shown in a modified example, biological information other than oxygen saturation can be used to pre-set conditions.

[0125] <Other embodiments>

[0126] The present disclosure is described through the above-disclosed embodiments, but it should be understood that the discussion and drawings constituting a part of the disclosure do not limit the present disclosure. For example, in the present disclosure, the unit for acquiring the pulse wave signal of the wrist artery is not limited to a watch-type device using a strap. For example, the oxygen saturation measuring device may also be a portable device that can be brought close to the wrist. In addition, the unit for acquiring the pulse wave signal of the wrist artery does not need to be a dedicated device for measuring oxygen saturation, for example, it may also be a general-purpose device with an oxygen saturation measuring function. That is, the method for measuring oxygen saturation is not limited by the device.

[0127] In addition, in the case of notifying a warning based on the breathing state of the person being measured, for example, a necklace-type respiratory rate measuring device that can be close to the chest of the person being measured may be used. In addition, in the present disclosure, the notification unit is not necessary. For example, the oxygen saturation measured by the second sensor unit may be sent to the outside through the communication function, and the sent oxygen saturation may be displayed on a display device provided outside as a notification unit. In addition, the present disclosure may be constructed without using the second sensor unit.

[0128] The present disclosure includes various embodiments and the like that are not described above, and the technical scope of the present disclosure is determined only by the invention-specific matters of the claims that are appropriate based on the above description.

[0129] The disclosure of Japanese Patent Application No. 2022-115117 filed on July 19, 2022 is incorporated herein by reference in its entirety.

[0130] In addition, all documents, patent applications and technical standards described in this specification are incorporated herein by reference to the same extent as if each document, patent application and technical standard was specifically and individually described as being incorporated by reference.

Claims

1. An oxygen saturation measuring device, comprising: The belt is wrapped around the wrist of the person being measured; a first sensor unit mounted on the belt and configured to obtain a pulse wave signal of the artery of the wrist and measure the oxygen saturation of the artery of the wrist based on the obtained pulse wave signal; and The notification unit notifies the measurement subject of a warning indicating a possibility of abnormality in the respiratory organ when the oxygen saturation measured by the first sensor unit satisfies a preset condition.

2. The oxygen saturation measurement device according to claim 1, wherein: The first sensor portion is mounted on the inner side of the belt.

3. The oxygen saturation measurement device according to claim 1 or 2, wherein: When the measured oxygen saturation level does not reach a preset reference value, the notification unit notifies the measurement subject as the warning to urge the subject to measure the oxygen saturation level at a fingertip position.

4. The oxygen saturation measurement device according to claim 1 or 2, wherein: The oxygen saturation measurement device further includes a second sensor unit that is attached to the belt and is used to measure the oxygen saturation of an artery at a fingertip of the measurement subject.

5. The oxygen saturation measurement device according to claim 4, wherein: The second sensor portion is mounted on the outer side of the belt.

6. An oxygen saturation measuring device comprising: The belt is wrapped around the wrist of the person being measured; a first sensor unit, mounted on the belt, for acquiring a pulse wave signal of the artery of the wrist and measuring the oxygen saturation of the artery of the wrist based on the acquired pulse wave signal; a notification unit configured to notify the subject of a warning indicating a possibility of abnormality in the respiratory organ when the oxygen saturation measured by the first sensor unit satisfies a preset condition; a second sensor unit mounted on the belt and configured to measure the oxygen saturation of an artery at a fingertip of the person being measured; as well as The display unit displays the oxygen saturation measured by the second sensor unit.

7. The oxygen saturation measuring device according to claim 6, wherein: The notification portion and the display portion are integrated.

8. A method for measuring oxygen saturation, comprising: Acquiring a pulse wave signal of an artery at the wrist of a subject; Determining the oxygen saturation of the artery according to the acquired pulse wave signal; as well as When the measured oxygen saturation satisfies a preset condition, a warning is notified to the subject.

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