JP5895476B2 - Respiration measurement method and respiration measurement device - Google Patents

Description

  The present disclosure relates to a respiratory measurement method and a respiratory measurement device.

  As a technique for measuring the respiratory motion of the subject by a sensor attached to the subject, a technique has been proposed in which the movement of the chest when the subject breathes is measured using an angular velocity sensor (see Patent Document 1).

  In the technique of Patent Document 1, the angular velocity sensor is mounted on the xiphoid portion of the subject in the supine position, thereby measuring the angular velocity of the movement of the xiphoid portion in a plane including the spine of the subject and perpendicular to the back surface of the subject. Based on the result, the respiratory motion of the subject is measured.

JP 2000-350716 A

  In the technique of Patent Document 1, simplification of processing of measurement results is measured by specifying the mounting position of the angular velocity sensor. On the other hand, since the mounting position of the angular velocity sensor is limited to the xiphoid projection, for example, an angular velocity sensor for respiratory measurement must be mounted separately from the sensor mounted on the chest for ECG examination, etc. This will increase the burden on the subject. In addition, since the direction of motion measured by the angular velocity sensor is limited, it has been difficult to apply to a subject in a posture other than the supine position.

  An object of the present disclosure is to provide a respiration measurement method and a respiration measurement apparatus capable of measuring the respiration movement of a subject with high accuracy regardless of the mounting position of the sensor.

A respiratory measurement method according to one aspect includes a first angular velocity of a motion that rotates in a first plane that coincides with or is perpendicular to a plane including the back surface of the subject from an angular velocity sensor attached to the chest or upper abdomen of the subject in a lying state. And a second measurement value indicating a second angular velocity of a motion rotating in a second plane orthogonal to the first plane, and obtaining the first measurement value and the second measurement value. by integrating the first rotation angle and the linear the subject of the neck of the first connecting the projection of the angular velocity sensor to the neck and the first plane of the subject with respect to the second plane as the origin the obtains a second rotation angle to the origin the subject of the neck of the straight line connecting the second projection of the angular velocity sensor to the neck and the second plane of the subject with respect to a plane, respectively, the first rotation angle and Based on the second rotation angle Te, calculates a third rotation angle with the origin the subject of the neck of a straight line connecting the neck of the subject with respect to the first plane or the second plane and the angular velocity sensor, the time of the third rotation angle Information indicating the movement of the chest accompanying breathing of the subject is collected from the change.

Further, the respiratory measuring device according to another aspect, a velocity sensor mounted on the subject's chest or upper abdomen of lying state, rotates the first plane that is coincident with or perpendicular to the plane containing the back of the subject motion An angular velocity sensor that outputs a first measured value indicating a first angular velocity of the first and a second measured value indicating a second angular velocity of a motion rotating in a second plane orthogonal to the first plane; and the first measured value And by integrating the second measured value, the subject's neck that is a straight line connecting the subject's neck with respect to the second plane and the first projection of the angular velocity sensor onto the first plane is used as the origin. A first rotation angle and a second rotation angle having a straight line connecting the subject's neck with respect to the first plane and the second projection of the angular velocity sensor on the second plane as the origin are obtained. An integration unit; Based on the rotation angle and the second rotation angle, the third angle of rotation as the origin the subject of the neck of a straight line connecting the neck and the angular velocity sensor of the subject with respect to the first plane or the second plane A calculating unit that calculates, and a collecting unit that collects information indicating movement of the chest associated with breathing of the subject from time variation of the third rotation angle.

  According to the respiratory measurement method and the respiratory measurement device of the present disclosure, it is possible to measure the respiratory motion of the subject with high accuracy regardless of the sensor mounting position.

It is a figure which shows one Embodiment of a respiration measuring apparatus. It is a figure explaining the model showing respiratory motion. It is a figure explaining the change of the angle by breathing exercise. It is a figure which shows another embodiment of a respiration measuring device. It is a figure which shows an example of the time change of angle (PSI). It is a figure which shows the hardware structural example of a respiration measuring device. It is a figure which shows an example of the flowchart of a respiration measurement process. FIG. 10 is a diagram (part 1) illustrating an example of a flowchart of a process for detecting a change point in a respiratory state; FIG. 11 is a diagram (part 2) illustrating an example of a flowchart of a process for detecting a change point in a respiratory state; It is a figure which shows another embodiment of a respiration measuring device. It is a figure explaining the relationship between a test subject's attitude | position and gravity acceleration. It is a figure which shows another example of the hardware constitutions of a respiration measuring apparatus. It is a figure which shows the flowchart of another example of a respiration measurement process. It is a figure which shows an example of the flowchart of the process which determines the transfer to a sleep state. It is a figure which shows an example of the flowchart of the process which determines continuation of a sleep state. It is a figure which shows one Embodiment of the sleep apnea detection apparatus. It is a figure which shows the hardware structural example of the sleep apnea detection apparatus. It is a figure which shows an example of the flowchart of a sleep apnea detection process. It is a transition determination to sleep state and a sleep posture determination process. It is a figure which shows an example of the flowchart of the recording process of apnea time, and the count process of the number of apneas.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating an embodiment of a respiration measurement device 10. The respiration measurement apparatus 10 illustrated in FIG. 1 measures at least one parameter representing the respiration motion of the subject P1 based on the measurement value obtained by the angular velocity sensor 11 attached to the subject P1.

  The origin O of the coordinate system illustrated in FIG. 1 substantially coincides with the location where the neck of the subject P1 lying on the bed is in contact with the bed or pillow. The z-axis direction substantially coincides with the spine of the subject P1, and the yz plane substantially coincides with the plane including the back surface of the subject P1. For this reason, when the subject P1 is lying on the bed in a supine position, the x-axis substantially coincides with the vertical direction. The yz plane and the xz plane exemplified in FIG. 1 are examples of a first plane and a second plane that are orthogonal to each other. Further, both the yz plane and the xz plane illustrated in FIG. 1 include the spinal column of the subject P1.

  The angular velocity sensor 11 illustrated in FIG. 1 is a gyro sensor, for example, and is attached to a position A on the left side of the chest of the subject P1. As described above, the respiratory measurement device 10 of the present disclosure includes the following movements of the angular velocity sensor 11 accompanying the respiratory motion of the subject P1, including the case where the mounting position A of the angular velocity sensor 11 is out of the median plane of the subject P1. Measure based on the model described.

  In the present disclosure, the movement of the angular velocity sensor 11 associated with the respiratory movement of the subject P1 is determined based on the wearing position A of the angular velocity sensor 11 with the origin O corresponding to the location where the neck of the subject P1 is in contact with the bed or pillow as a fulcrum. Modeled as rotational motion.

  FIG. 2 is a diagram for explaining a model representing respiratory motion. FIG. 2A shows the projection of the change in the position of the angular velocity sensor 11 accompanying the respiratory motion of the subject P1 onto the xz plane. FIG. 2B shows the projection of the change in position of the angular velocity sensor 11 accompanying the respiratory motion of the subject P1 onto the yz plane.

  In FIG. 2 (A), symbol Qye indicates an example of the contour of the chest when the subject P1 exhales, and symbol Qy indicates the contour of the chest that expands in response to the inhalation action of the subject P1. An example is shown. The change in the position of the angular velocity sensor 11 in the xz plane accompanying the deformation of the contour of the chest is a rotational motion with the y axis of the straight line connecting the projection of the angular velocity sensor 11 on the xz plane and the origin O as the rotation axis. Can be understood as In FIG. 2A, the projection of the angular velocity sensor 11 on the xz plane when the subject P1 has exhaled is indicated by the symbol Ce, and the xz of the angular velocity sensor 11 in the process of expanding the rib cage of the subject P1. The projection onto the plane is indicated by C. In FIG. 2A, the symbol θe indicates the angle formed by the straight line connecting the projection Ce and the origin O and the z axis, and the symbol θ indicates the straight line connecting the projection C and the origin O by the z axis. Indicates the angle to make.

  Similarly, in FIG. 2B, the symbol Qxe indicates an example of the contour of the chest when the subject P1 has exhaled, and the symbol Qx indicates the chest that swells according to the inhalation operation of the subject P1. An example of the contour is shown. The change in the position of the angular velocity sensor 11 in the yz plane accompanying the deformation of the outline of the chest is a rotational motion with the x axis of the straight line connecting the projection of the angular velocity sensor 11 onto the yz plane and the origin O as the rotation axis. Can be understood as In FIG. 2B, the projection onto the yz plane of the angular velocity sensor 11 when the subject P1 has exhaled is indicated by the symbol Be, and the yz of the angular velocity sensor 11 in the process of expanding the thorax of the subject P1. The projection onto the plane is denoted by B. In FIG. 2B, the symbol φe indicates an angle formed by the straight line connecting the projection Be and the origin O and the z axis, and the symbol φ indicates the straight line connecting the projection B and the origin O by the z axis. Indicates the angle to make.

  As shown in FIG. 1, the angle Ψ formed by the straight line OA connecting the mounting position A of the angular velocity sensor 11 and the origin O and the yz plane is expressed by the equation (1) using the angle θ and the angle φ described above. Can be expressed as:

  Also, the angle θ and the angle φ illustrated in FIGS. 1 and 2 are expressed by the equations (2) and (3), respectively, using the angle θe and the angle φe in the state where the subject P1 exhales as illustrated in FIG. ). The angular velocity gy (t) shown in the equation (2) is an angular velocity of a rotational motion with the y axis as a rotation axis obtained by the angular velocity sensor 11 illustrated in FIG. 1, and the angular velocity gx shown in the equation (3). (t) is the angular velocity of the rotational motion with the x-axis obtained by the angular velocity sensor 11 as the rotational axis.

  Therefore, the above-described angle Ψ can be obtained based on the angular velocities gx and gy of the rotational movement with the x-axis and the y-axis as the rotation axes obtained by the angular velocity sensor 11 illustrated in FIG. Then, based on the angle Ψ thus obtained, the movement of the mounting position A of the angular velocity sensor 11 can be expressed as a rotational movement of the mounting position A with the origin O as a fulcrum.

Note that the angular velocity gy in the xz plane and the angular velocity gz in the xy plane may be acquired from the angular velocity sensor 11, and the angle Ψ may be obtained based on these angular velocities gy and gz. Further, the angular velocity gx in the yz plane and the angular velocity gz in the xy plane may be acquired from the angular velocity sensor 11, and the angle Ψ may be obtained based on these angular velocities gx and gz. Based on such a model, the angular velocity sensor In order to measure the motion of the 11 wearing positions A, the respiratory measurement apparatus 10 illustrated in FIG. 1 includes an integration unit 12, a calculation unit 13, and a collection unit 14.

  The integrator 12 integrates the angular velocities gy and gx received from the angular velocity sensor 11 to obtain the above-described angle θ and angle φ, respectively. The calculating unit 13 substitutes the angle θ and the angle φ obtained by the integrating unit 12 into the above-described equation (1), so that the straight line connecting the origin O and the mounting position A of the angular velocity sensor 11 is an angle formed with the yz plane. Ψ is calculated.

  Here, the angle Ψ calculated by the calculation unit 13 using the equation (1) faithfully reflects the movement of the chest due to the respiratory motion of the subject P1, regardless of the mounting position A of the angular velocity sensor 11. Therefore, the collection unit 14 can collect information indicating the movement of the chest associated with the breathing of the subject P1 based on the time change of the angle Ψ obtained by the calculation unit 13.

  FIG. 3 is a diagram for explaining a change in angle associated with respiratory motion. 3 that are the same as those shown in FIGS. 1 and 2 are denoted by the same reference numerals and description thereof is omitted. In FIG. 3, reference sign Qe is an example of the contour of the chest when the subject P1 exhales, and reference sign Qb is an example of the contour of the chest when the subject P1 transitions from inspiration to expiration. is there.

  In FIG. 3, the symbol Ae indicates the position of the angular velocity sensor 11 when the subject P1 has exhaled, and the symbol Ab indicates the position of the angular velocity sensor 11 when the subject P1 shifts from inspiration to expiration. . On the other hand, symbol Bb indicates the projection of the position of the angular velocity sensor 11 on the yz plane when the subject P1 shifts from inspiration to expiration. Similarly, the symbol Cb indicates the projection of the position of the angular velocity sensor 11 on the xz plane when the subject P1 shifts from inspiration to expiration. Therefore, the angle dθ formed by the straight line OCe and the straight line OCb indicates a difference between the angle θ during exhalation and the angle θ during inspiration, and the angle dφ formed by the straight line OBe and the straight line OBb is the angle φ and the inspiration during exhalation. The difference from the angle φ at the time is shown.

  As can be seen from FIG. 3, the angle dθ represents a component whose rotational axis is the y axis of the rotational motion corresponding to the process in which the end point A of the straight line OA moves from the point Ae to the point Ab. The angle dφ represents a component having the rotational axis as the rotational axis corresponding to the process of moving the end point A of the straight line OA from the point Ae to the point Ab. Since the angle dΨ indicating the difference between the angle Ψ during expiration and the angle Ψ during inspiration reflects both the angle dθ and the angle dφ described above, the angle indicating the difference associated with the respiratory motion of the angle Ψ. dΨ is larger than the angle dθ and the angle dφ described above. Therefore, by analyzing such a time change of the angle Ψ, the collection unit 14 can collect information indicating the movement associated with the breathing of the subject P1 with high accuracy. Moreover, the angle Ψ can be calculated using the above-described equation (1) regardless of the position of the angular velocity sensor 11 on the chest or upper abdomen of the subject P1.

  As described above, according to the respiratory measurement device 10 of the present disclosure illustrated in FIG. 1, the respiratory motion of the subject P <b> 1 can be measured with high accuracy regardless of the mounting position of the angular velocity sensor 11. That is, according to the respiration measurement device 10 of the present disclosure, it is possible to eliminate restrictions on a position where an angular velocity sensor used for measurement of respiration motion is attached.

  Thereby, for example, by accumulating the angular velocity sensor 11 on one sheet-like member together with a sensor for acquiring an electrocardiogram, and mounting the sheet-like member at a position close to the heart of the subject P1, It becomes possible to measure the respiratory motion of the subject P1 with high accuracy. Thus, by making it possible to integrate the sensor for respiratory measurement and the sensor for acquiring an electrocardiogram into one, it is possible to reduce the physical and psychological burden on the subject P1 wearing the sensor.

  The angular velocity sensor 11 may be attached to the right chest, upper abdomen, etc. of the subject P1 without being limited to the examples in FIGS.

  The model showing the relationship between the angle Ψ, the angle θ, and the angle φ described above is not limited to the posture of the subject P1 in the supine position, and is an intermediate posture between the supine position and the supine position and the supine position. Is applicable. Therefore, according to the respiratory measurement device 10 of the present disclosure illustrated in FIG. 1, the respiratory motion of the subject P1 can be measured with high accuracy regardless of the posture of the subject P1.

  FIG. 4 is a diagram illustrating another embodiment of the respiratory measurement device 10. 4 that are the same as those shown in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  The integration unit 12 included in the respiratory measurement device 10 illustrated in FIG. 4 includes a noise removal unit 15 and an integration calculation unit 16.

The noise removing unit 15 includes, for example, a low-pass filter such as a Chebyshev filter or a Butterworth filter. The noise removing unit 15 removes high frequency noise components of the angular velocities gx and gy by inputting the output signal of the angular velocity sensor 11 to the low-pass filter. Furthermore, the noise removing unit 15 may remove the drift component from the output of the low-pass filter. The noise removing unit 15 uses angular velocities g′x (j) and g′y (j) indicated by output values obtained by sampling the output of the low-pass filter using, for example, the equations (4) and (5). Then, the angular velocities gx (j) and gy (j) after removing the drift component may be calculated. In equations (4) and (5), the average values of the angular velocities g′x (j) and g′y (j) indicated by the output values of the low-pass filter obtained within a predetermined period are expressed as numerical values Egx and Egy. Indicated.
gx (j) = g′x (j) −Egx (4)
gy (j) = g′y (j) −Egy (5)
Based on the angular velocities gy and gx from which the noise components have been removed in this way, the integration calculation unit 16 performs the integration process shown in the above-described equations (6) and (7), so that the calculation unit 13 has the sampling time. A highly accurate value can be input as the angle θ (j) and the angle φ (j) at Tj.

  Accordingly, the calculation unit 13 included in the respiratory measurement device 10 illustrated in FIG. 4 can calculate the angle Ψ (j) at each sample time Tj with high accuracy.

  Thus, the angle Ψ (j) calculated corresponding to each sample time Tj is input to the analysis unit 18 through the smoothing unit 17 included in the collection unit 14 illustrated in FIG. 4.

  The smoothing unit 17 illustrated in FIG. 4 performs a moving average process for a predetermined period on the angle Ψ (j) at each sample time Tj received from the calculation unit 13 to thereby change the time Ψ (j) over time. Smooth.

  FIG. 5 shows an example of the time change of the angle Ψ. 5A and 5B, the horizontal axis indicates the passage of time t, and the vertical axis indicates the magnitude of the angle Ψ.

  The analysis unit 18 illustrated in FIG. 4 analyzes the time change of the angle Ψ (j) to change the breathing state of the subject P1 from the inhalation state to the expiration state, and from the expiration state to the inspiration state. Detect change points that change.

  The curve graph illustrated in FIG. 5 (A) shows an angle Ψ (t) that changes regularly according to the regular breathing motion of the subject P1. In such a case, the analysis unit 18 can detect the change point of the respiratory state described above by detecting the time when the angle Ψ takes the extreme value.

  For example, the analysis unit 18 detects the point at which the angle Ψ (t) turns from decreasing to increasing, so that each time point indicated by reference numerals Te1, Te2, Te3, Te4, and Te5 in FIG. This is detected as a change point at which the breathing state changes from the expiration state to the inspiration state. Further, the analysis unit 18 detects the point at which the angle Ψ (t) changes from increasing to decreasing, and thereby, the time points indicated by the symbols Tb1, Tb2, Tb3, and Tb4 in FIG. You may detect as a change point in which a state changes from an inhalation state to an expiration state.

  Here, prior to the processing of the analysis unit 18, the smoothing unit 17 smoothes the time change of the angle Ψ (j) obtained by the calculation unit 13, so that the analysis unit 18 has little local fluctuation. Based on the angle Ψ (t), the extreme value of the graph showing the time change of the angle Ψ can be detected. Thereby, the analysis part 18 can detect the change point of the respiration state which reflected the regularity of the fluctuation | variation accompanying the respiration exercise | movement of the test subject P1 faithfully.

  Then, based on the change point of the respiratory state detected in this way, the analysis unit 18, for example, of the change point from the expiration state to the inspiration state as indicated by reference characters τ1 to τ4 in FIG. The interval may be calculated as the respiratory cycle of the subject P1. In this manner, the collection unit 14 including the smoothing unit 17 and the analysis unit 18 illustrated in FIG. 4 can collect information on the respiratory motion of the subject P1 based on the time change of the angle Ψ.

  On the other hand, when the respiratory motion of the subject P1 has irregular characteristics, the graph of the angle Ψ (t) has a plurality of local peaks as illustrated by reference symbols P3 and P4 in FIG. Valleys or mountains may appear.

Regardless of the presence of such a local peak, in order to evaluate the respiration periodicity of the subject P1, the analysis unit 18 detects a change point of the respiration state when the following conditions are satisfied. It is desirable.
(1) A condition for detecting a changing point from an inhalation state to an exhalation state. The angle Ψ (t) is a maximum value.
The angle Ψ (t) is larger than the average value within the predetermined time Td.
-Another predetermined time Thb or more has elapsed from the point of change from the previous inhalation state to the expiration state.
・ The breathing state is the inhalation state.
(2) The condition for detecting the change point from the expiration state to the inspiration state, the angle Ψ (t) is a minimum value.
The angle Ψ (t) is smaller than the average value within the predetermined time Td.
-Another predetermined time The has elapsed from the point of change from the previous expiration state to the inspiration state.
・ The breathing state is an expired state.

  Moreover, when the analysis part 18 detects the change point which changes from an inhalation state to an expiration state, subsequent analysis processing is continued by making a breathing state into an expiration state. Similarly, when the analysis unit 18 detects a change point that changes from the expiration state to the inhalation state, the analysis unit 18 continues the subsequent analysis process with the breathing state as the inhalation state. Note that the predetermined time Td, which is a period for which the average value of the angle Ψ (t) is calculated, may be determined based on an average human respiratory cycle or the like. For example, the average human respiratory cycle or the average value of the respiratory cycle of the subject P1 measured so far can be set as the predetermined time Td. Similarly, the predetermined time Thb and the predetermined time The may be determined based on a value obtained by multiplying an average human respiratory cycle by an appropriate coefficient. For example, a time obtained by multiplying the average human respiratory cycle or the average value of the respiratory cycle of the subject P1 measured so far by a predetermined coefficient larger than the value 0.5 and smaller than the value 1 is the predetermined time Thb. Alternatively, the predetermined time The may be used.

  When detecting the change point of the respiratory state based on such conditions, the analysis unit 18 shows the local peak indicated by the symbol P3 in FIG. Based on the third or third condition, it can be determined that it is not the change point of the respiratory state. Similarly, the analysis unit 18 converts the local peak indicated by the symbol P4 in FIG. 5B based on the second or third condition indicated in the above item (2) to the change point of the respiratory state. It can be judged that it is not.

  In this way, by using the analysis unit 18 that detects the change point of the respiratory state using the conditions shown in the above items (1) and (2), irregularities such as snoring in the respiratory motion of the subject P1 Even if there is a characteristic, it is possible to obtain an accurate respiratory cycle.

The respiration measurement device 10 of the present disclosure can be realized using, for example, a computer device such as a personal computer.
FIG. 6 shows an example of the hardware configuration of the respiratory measurement device 10.

  The computer device 20 includes a processor 21, a memory 22, a hard disk device 23, a display device 24, an input device 25, an optical drive device 26, and a sensor interface 28. The processor 21, the memory 22, the hard disk device 23, the display device 24, the input device 25, the optical drive device 26, and the sensor interface 28 illustrated in FIG. 6 are connected to each other via a bus. The optical drive device 26 illustrated in FIG. 6 can be mounted with a removable disk 27 such as an optical disk, and reads and records information recorded on the mounted removable disk 27. The respiratory measurement device 10 illustrated in FIG. 6 includes a processor 21, a memory 22, a hard disk device 23, and a sensor interface 28.

  The computer apparatus 20 illustrated in FIG. 6 is connected to the angular velocity sensor 11 via the sensor interface 28.

  The input device 25 illustrated in FIG. 6 is, for example, a keyboard or a mouse. The operator of the respiratory measurement device 10 operates the input device 25 to give instructions to the respective units included in the respiratory measurement device 10 to start, for example, measurement of angular velocity or collection of information related to respiratory motion. Can be entered.

  The memory 22 stores an application program for the processor 21 to execute the respiration measurement process described above together with the operating system of the computer device 20. The application program for executing the above-described respiration measurement process can be recorded and distributed on, for example, a removable disk 27 such as an optical disk. Then, by loading the removable disk 27 in the optical drive device 26 and performing a reading process, an application program for executing a respiration measurement process may be stored in the memory 22 and the hard disk device 23. In addition, an application program for executing respiration measurement processing can be read into the memory 22 and the hard disk device 23 via a communication device (not shown) connected to a network such as the Internet.

  Further, the processor 21 may perform the functions of the integration unit 12, the calculation unit 13, and the collection unit 14 illustrated in FIG. 1 by executing an application program stored in the memory 22.

  FIG. 7 shows an example of a flowchart of the respiration measurement process. Each process of step S301 to step S313 shown in FIG. 7 is an example of a process included in the above-described application program for the respiration measurement process. In addition, each processing of step S301 to step S313 is executed by the processor 21.

  First, the processor 21 sets one of an inspiratory state and an expiratory state as an initial state as a respiration state of the subject P1 referred to in the subsequent respiration measurement processing (step S301). Hereinafter, a case where the processor 21 sets the inspiratory state as the initial state of the breathing state of the subject P1 in step S301 will be described as an example.

  Next, the processor 21 outputs, via the sensor interface 28, output signals indicating the angular velocities gy and gx obtained by the angular velocity sensor 11 within a period corresponding to the acquisition interval τr, for example, at every predetermined acquisition interval τr. Obtain (step S302). Next, the processor 21 performs a process of removing the high frequency noise component and the drift component from the output signal of the angular velocity sensor 11 (step S303). For example, the processor 21 may remove the high-frequency component by performing a process of applying a low-pass filter to the output signal of the angular velocity sensor 11. Further, the processor 21 indicates the sampling result obtained by sampling the output signal of the angular velocity sensor 11 after the high frequency component is removed at a predetermined sampling period, by the above-described equations (4) and (5). Process. Thereby, the processor 21 calculates the angular velocities gy (j) and gx (j) from which the high frequency component and the drift component have been removed corresponding to each sampling timing Tj included in the period in which the output signal is acquired in step S302. Can be obtained. Instead of the processor 21 executing the process for removing the high frequency component in step S303, the processor 21 may receive the output signal of the angular velocity sensor 11 via a low-pass filter provided in the sensor interface 28.

  After that, the processor 21 integrates the angular velocities gy (j) and gx (j), so that the angles θ (j) and φ () at each sampling timing Tj included in the period in which the output signal is acquired in step S302. j) is calculated (step S304).

  As described above, the processor 21 executes the processing from step S302 to step S304, thereby realizing the function of the integration unit 12 illustrated in FIGS. 1 and 4.

  Then, using the angle θ (j) and the angle φ (j) calculated in step S304 and the above-described equation (1), the processor 21 calculates the angle Ψ (j) at each sampling timing Tj (step S305). ). As described above, the function of the calculation unit 13 illustrated in FIGS. 1 and 4 can be realized by the processor 21 executing the process of step S305.

  Next, the processor 21 performs a process of smoothing the time change of the angle Ψ accompanying the respiratory motion of the subject P1 based on the angle Ψ (j) at Tj at each sampling timing obtained in the process of step S305 ( Step S306). For example, as described in the description of the smoothing unit 17 illustrated in FIG. 4, the processor 21 performs the moving average process on the angle Ψ (j), thereby performing the angle Ψ (at each sampling timing Tj after the smoothing process. j) may be determined.

  Next, the processor 21 detects the change point of the respiratory state within the above-described period based on the time change of the angle Ψ (j) at each sampling timing Tj after the above-described smoothing process (step S307). In step S307, for example, the processor 21 changes the point from the inhalation state to the expiration state and the expiration state based on the conditions described in the items (1) and (2) in the description of the analysis unit 18 illustrated in FIG. A process for detecting each change point from the intake state to the intake state is performed. Details of the process in step S307 will be described later.

  When the change point from the expiration state to the inhalation state is detected by the process of step S307 (Yes determination in step S308), the processor 21 first sets the breathing state of the subject P1 to the inhalation state (step S309). . Next, the processor 21 adds the value 1 to the number of breaths n (step S310). Thereafter, the processor 21 proceeds to the process of step S313.

  On the other hand, when the change point from the expiration state to the inhalation state is not detected by the process in step S307 (No determination in step S308), the processor 21 first detects the change point from the inspiration state to the expiration state. It is determined whether or not (step S311).

  If the determination in step S311 is affirmative, the processor 21 sets the breathing state of the subject P1 to the expiration state (step S312). Thereafter, the processor 21 proceeds to the process of step S313. On the other hand, in the case of a negative determination in step S311, the processor 21 proceeds to the process of step S313 as it is.

  In this manner, the processor 21 can detect the change in the respiratory state of the subject P1 and collect information such as the number of breaths by executing the processing of steps S307 to S312. That is, the processor 21 executing the processing from step S307 to step S312 is an example of a method for realizing the collection unit 14 illustrated in FIGS. 1 and 4.

  In the flowchart illustrated in FIG. 7, in step S301, the inspiratory state is set as the initial state of the breathing state of the subject P1, so the number of breaths n is added each time a change point to the inspiratory state is detected. Yes. Therefore, if the initial upper body set in step S301 is in the expired state, the number of breaths may be added each time the expired state is detected. In any case, the measurement error of the number of breaths is less than half breath. Moreover, based on the tendency of the output signal obtained from the angular velocity sensor 11 when starting the respiration measurement process, the initial state can be set reflecting the actual respiration state of the subject P1.

  Thereafter, the processor 21 determines whether or not to stop the measurement based on whether or not an instruction to stop the respiration measurement process is input from the input device 25 or the like (step S313).

  If there is no instruction to stop the respiration measurement process, the processor 21 proceeds to a negative determination route in step S313. In this case, the processor 21 returns to the process of step S302, and executes a measurement process (step S314) including the processes of steps S302 to S312 based on the newly obtained output signal of the angular velocity sensor 11.

  On the other hand, when an instruction to stop the respiration measurement process is input by the operator of the respiration measurement apparatus 10, the processor 21 proceeds to the affirmative determination route of step S313 and ends the respiration measurement process.

  Next, a method for realizing the process of step S307 illustrated in FIG. 7 by the process of the processor 21 will be described.

  8 and 9 show an example of a flowchart of processing for detecting a change point of the respiratory state. The flowchart illustrated in FIG. 8 and the flowchart illustrated in FIG. 9 are both part of a flowchart of processing for detecting the change point of the respiratory state shown in step S307 in FIG. The two flow charts are connected to each other by connectors denoted by reference numerals 1, 2, and 3. The processing of each step included in these flowcharts is an example of a technique for realizing the function of the analysis unit 18 illustrated in FIG.

  Based on the angle Ψ (j) obtained in step S305 illustrated in FIG. 7 and the angle Ψ of a predetermined period obtained before that, the processor 21 calculates the average value Ψav of the angles Ψ within the unit time. Is calculated (step S321). For example, the processor 21 holds the angle Ψ (j) obtained in step S305 for a predetermined time Td corresponding to the average respiratory cycle, and in the process of step S321, the average value Ψav of the angle Ψ is You may use for calculation.

  Further, the processor 21 pays attention to the angle Ψ (j) at the j-th sampling timing, and based on the difference between the angle Ψ (j) and the angle Ψ (j + 1) at the next sampling timing, the time change of the angle Ψ. Is calculated (step S322).

  Next, the processor 21 determines whether or not the breathing state of the subject P1 is an inhalation state (step S323). When the breathing state of the subject P1 is the inhalation state, the processor 21 proceeds to the affirmative determination route of step S323, and executes a process of detecting a change point to the expiration state including steps S324 to S329. That is, the processor 21 executes the process of detecting the change point to the expiration state only when the fourth condition of the above item (1) is satisfied.

  In the affirmative determination route of step S323, the processor 21 first calculates the time tb from the time Tb at which the change point to the previous expiration state was detected to the jth sampling timing at which the differential coefficient dΨ (j) was calculated in step 322. Calculate (step S324). In the following description, a time corresponding to the jth sampling timing is referred to as a sampling time Tj.

  Next, the processor 21 determines whether or not the first condition of the above-described item (1) is satisfied based on whether or not the derivative dΨ (j) calculated in step S322 is a negative value. (Step 325). In the case of an affirmative determination in step S325, the processor 21 further determines whether or not the angle Ψ (j) of interest is larger than the average value Ψav calculated in step S321. It is determined whether the second condition of the item (1) is satisfied (step 326). In the case of an affirmative determination in step S326, the processor 21 determines whether the time tb obtained in step S324 exceeds the predetermined time Thb described above, thereby determining the third item (1) described above. It is determined whether or not the above condition is satisfied (step 327).

  When the processing in steps S325 to S327 indicates that all the conditions in the above item (1) are satisfied, the processor 21 performs the processing in steps S328 and S329 according to the affirmative determination route in step S327. Run. In step S328, the processor 21 sets the sample time Tj to the detection time Tb of the change point to the new expiration state. In step S329, the processor 21 outputs the fact that the change point to the expiration state has been detected as a processing result, and ends the process of detecting the change point.

  Incidentally, when the current breathing state of the subject P1 is the expiration state, the processor 21 proceeds to the process of the flowchart of FIG. 9 connected by the connector 1 according to the negative determination route of step S323 described above. And the process which detects the change point to the inhalation state including the process of step S331-step S336 is performed. That is, the processor 21 executes the process of detecting the change point to the intake state only when the fourth condition of the above item (2) is satisfied.

  First, the processor 21 calculates a time te from the time Te at which the change point to the previous intake state is detected to the sample time Tj described above (step S331).

  Next, the processor 21 determines whether or not the first condition of the above-described item (2) is satisfied based on whether or not the derivative dΨ (j) calculated in step S322 is a positive value. (Step 332). In the case of an affirmative determination in step S332, the processor 21 further determines whether or not the angle Ψ (j) of interest is smaller than the average value Ψav calculated in step S321 as described above ( It is determined whether or not the second condition of item 2) is satisfied (step 333). In the case of an affirmative determination in step S333, the processor 21 determines whether the time te obtained in step S331 exceeds the predetermined time The described above, thereby determining the third item in the above-described item (2). It is determined whether or not the above condition is satisfied (step 334).

  When the processing in steps S332 to S334 indicates that all the conditions in the above-mentioned item (2) are satisfied, the processor 21 performs the processing in steps S335 and S336 according to the affirmative determination route in step S334. Run. In step S335, the processor 21 sets the sample time Tj to the detection time Te of the change point to the new intake state. In step S336, the processor 21 outputs a processing result indicating that the change point to the intake state has been detected, and returns to the flowchart of FIG. finish.

  On the other hand, when it is shown that any of the conditions of the above-mentioned item (2) is not satisfied, the processor 21 shows the result shown in FIG. 8 via the connector 2 according to the negative determination route of steps S332 to S334. The process proceeds to step S330.

  Similarly, when it is indicated that any one of the above conditions (1) is not satisfied, the processor 21 executes the process of step S330 according to the negative determination route of steps S325 to S327.

  In step S330, the processor 21 determines whether or not there is an unprocessed angle Ψ (j). If the determination in step S330 is affirmative, the processor 21 returns to the process of step 322, and starts the process of detecting the change point of the respiratory state based on the new angle Ψ (j) corresponding to the next sampling timing. To do.

  In this way, when the processor 21 repeats the processing of steps S322 to S336 illustrated in FIGS. 8 and 9 and the change point of the respiratory state is not detected, the processor 21 negates step S330. The process is terminated via the determination route. In this case, the processor 21 may output that the change point of the respiratory state is not detected for the above-described period.

  Thus, the respiration measuring device 10 illustrated in FIG. 1 and FIG. 4 is realizable when the processor 21 of the computer apparatus 20 performs each process mentioned above.

  Next, a preferred embodiment will be described when the respiratory measurement device 10 of the present disclosure measures respiratory motion during sleep of the subject P1.

  FIG. 10 shows another embodiment of the respiratory measurement device 10. 10 that are equivalent to the components shown in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  The acceleration sensor 19 is mounted together with the angular velocity sensor 11 on the chest of the subject P1 shown in FIG. The mounting position of the acceleration sensor 19 may be the chest or upper abdomen of the subject P1 as in the angular velocity sensor 11. In the example illustrated in FIG. 10, the sensor unit 30 in which the angular velocity sensor 11 and the acceleration sensor 19 are integrated on a sheet-like base material is mounted on the left side of the chest of the subject P1.

  The acceleration sensor 19 illustrated in FIG. 10 measures the gravitational acceleration component in each coordinate axis direction of the coordinate system in which the z-axis is set in the spine direction of the subject P1 and the x-axis is set in the front-rear direction of the subject P1. Measurement values αx, αy, αz indicating the measured results are output. In addition, the y-axis direction of this coordinate system can be set to the left-right direction of the test subject P1, for example.

  Further, the respiratory measurement device 10 illustrated in FIG. 10 includes a determination unit 31 and a power control unit 32 in addition to the units illustrated in FIG.

  The determination unit 31 determines whether or not the subject P1 is in a sleep state based on the measurement values αx, αy, and αz obtained by the acceleration sensor 19. For example, the determination unit 31 determines that the subject P1 is in a sleep state based on the direction in which the gravitational acceleration mainly obtained from the measurement values αx, αy, and αz works and the fluctuation range in this direction.

  The power control unit 32 illustrated in FIG. 10 performs control to supply the driving power Dp to the angular velocity sensor 11 when the determination unit 31 determines that the subject P1 is in the sleep state.

  That is, according to the respiratory measurement device 10 illustrated in FIG. 10, the driving power Dp can be supplied to the angular velocity sensor 11 only when the subject P1 is sleeping. Since the angular velocity sensor 11 consumes more power than the acceleration sensor 19, by controlling the power supply to the angular velocity sensor 11 as described above, it is possible to save power in the respiratory measurement device 10. Moreover, since the respiration measurement process can be started without being operated by the subject P1 or the operator of the respiration measuring device 10, the work load on the subject P1 or the operator can be reduced.

  Here, a method for determining whether or not the subject P1 is in a sleep state based on the measurement values αx, αy, and αz obtained by the acceleration sensor 19 will be described.

  FIG. 11 is a diagram illustrating the relationship between the posture of the subject P1 and the gravitational acceleration. In FIG. 11, an arrow g indicates the direction of gravitational acceleration.

  11A and 11B show the coordinate axes and the direction of gravitational acceleration when the subject P1 is in the upright posture. 11A and 11B are a front view and a side view of the subject P1 standing upright. As can be seen from FIGS. 11A and 11B, the direction in which the gravitational acceleration g works when the subject P1 is in the upright posture or when the subject P1 is upright on the bed corresponds to the spine of the subject P1. The z-axis direction is

  On the other hand, FIG. 11C shows the coordinate axes and the direction of gravitational acceleration when the subject P1 is lying in the supine position on the bed. As can be seen from FIG. 11C, the direction in which the gravitational acceleration g works when the posture of the subject P1 on the bed is in the supine position substantially coincides with the x-axis direction corresponding to the direction penetrating the subject P1 back and forth. .

  FIG. 11D shows the coordinate axes and the direction of gravitational acceleration when the subject P1 is lying on his / her side on the bed. As can be seen from FIG. 11D, the direction in which the gravitational acceleration g works when the posture of the subject P1 is completely in the measuring position substantially matches the y-axis direction corresponding to the left-right direction of the subject P1.

  Although illustration is omitted, the direction in which the gravitational acceleration g works when the subject P1 is lying on the bed in an intermediate position between the supine position and the laterally lying position is in a plane substantially perpendicular to the spine of the subject P1. Indicated by a straight line.

  Therefore, for example, when the direction in which the gravitational acceleration calculated from the measurement values αx, αy, and αz is substantially perpendicular to the spine of the subject P1, the determination unit 31 illustrated in FIG. Can be determined to be lying.

  In addition, during the sleep, the movement of the subject P1 becomes very slow, so the fluctuation range in the direction in which the gravitational acceleration calculated from the measured values αx, αy, αz is reduced.

  Therefore, the determination unit 31 illustrated in FIG. 10 has a direction in which the gravitational acceleration acts in a direction substantially perpendicular to the spine of the subject P1 of the subject P1, and the fluctuation range in the direction in which the gravitational acceleration acts is smaller than a predetermined threshold. In this case, it may be determined that the subject P1 is in a sleep state.

  In this way, the determination unit 31 can determine whether or not the subject P1 is sleeping based on the measurement value of the acceleration sensor 19 corresponding to the coordinate axis direction fixed with respect to the subject P1.

  The respiratory measurement device 10 illustrated in FIG. 10 can also be realized using a computer device such as a personal computer.

  FIG. 12 shows another example of the hardware configuration of the respiratory measurement device 10. Note that among the constituent elements shown in FIG. 12, those equivalent to the constituent elements shown in FIG. 6 are denoted by the same reference numerals, and description thereof is omitted.

  A sensor interface 28 included in the respiratory measurement device 10 illustrated in FIG. 12 is connected to a sensor unit 30 including an angular velocity sensor 11 and an acceleration sensor 19. Then, the processor 21 can obtain the measurement values αx, αy, αz by the acceleration sensor 19 together with the measurement values gy, gx by the angular velocity sensor 11 via the sensor interface 28.

  The sensor unit 30 illustrated in FIG. 12 further includes a battery 34 and a switch 35. The processor 21 can control the power supply from the battery 34 to the angular velocity sensor 11 by operating the switch 35 via the sensor interface 28.

  Further, the memory 22 illustrated in FIG. 12 further includes an application program for causing the processor 21 to execute a respiration measurement process including a process of determining the sleep state of the subject P1 and a process of controlling power supply to the angular velocity sensor 11. Storing. Note that this application program for respiratory measurement processing including processing for determining a sleep state and processing for controlling power supply can also be recorded and distributed on a recording medium such as the removable disk 27, for example. Then, the application program for the respiration measurement process may be stored in the memory 22 and the hard disk device 23 by attaching the removable disk 27 to the optical drive device 26 and performing a reading process. Further, the application program for the respiration measurement process can be read into the memory 22 and the hard disk device 23 via a communication device (not shown) connected to a network such as the Internet.

  Further, the processor 21 executes the application program for the respiration measurement process stored in the memory 22 as described above, thereby including the determination unit 31 and the power control unit 32 illustrated in FIG. Ten functions can be performed.

  FIG. 13 shows another example of the flowchart of the respiration measurement process. Each process of step S341 to step S351 illustrated in FIG. 13 is an example of a process included in the above-described application program for the respiration measurement process. In addition, each processing of S341 to S351 is executed by the processor 21.

  First, the processor 21 sets “before sleep” as the initial state of the subject P1 (step S341). Next, the processor 21 acquires measurement values αx, αy, αz from the acceleration sensor 19 via the sensor interface 28 (step S342). For example, the processor 21 acquires the measurement values αx, αy, and αz of the acceleration sensor 19 obtained in the period corresponding to the acquisition time τr at the same acquisition interval τr as the acquisition of the measurement value of the angular velocity sensor 11 described above. .

  Then, based on the measurement values αx, αy, and αz of the acceleration sensor 19 obtained in step S342, the processor 21 executes a process for determining a shift to a sleep state described later (step S343).

  FIG. 14 shows an example of a flowchart of processing for determining the transition to the sleep state. Each step illustrated in FIG. 14 is an example of a process for determining the transition to the sleep state illustrated in Step S343 in FIG. 13, and is a method for realizing the determination unit 31 illustrated in FIG. 10 by the process of the processor 21. It is an example.

  For example, the processor 21 obtains the average direction in which the gravitational acceleration has worked during this period based on the measured values αx, αy, αz of the acceleration sensor 19 obtained at a plurality of sampling timings included in the above-described period. (Step S361). For example, the processor 21 calculates the average acceleration components Vx, Vy, Vz indicating the average direction in which the gravitational acceleration has worked by averaging the measured values αx, αy, αz at the respective sampling timings. Good.

  Next, the processor 21 determines whether or not the direction indicated by the average acceleration components Vx, Vy, and Vz obtained in step S361 is substantially perpendicular to the z axis (step S362). For example, when the average value Vz of the measured values αz of acceleration in the z-axis direction obtained in step S361 exceeds a predetermined threshold, the processor 21 determines that the direction in which the gravitational acceleration works corresponds to the spine of the subject P1. It is determined that the direction is not perpendicular to the axial direction (negative determination in step S362). In this case, the processor 21 determines that the state of the subject P1 continues the “before sleep” state (step S363), and proceeds to the process of step S344 in FIG.

  On the other hand, when the average value Vz of the acceleration measurement values αz in the z-axis direction obtained in step S361 is equal to or less than the above-described threshold value, the processor 21 determines that the direction in which the gravitational acceleration acts is substantially perpendicular to the spine of the subject P1. Judgment is made (affirmative determination in step S362). In this case, for example, the processor 21 performs the direction in which the gravitational acceleration works based on the difference between the measured values αx, αy, αz obtained at each sampling timing and the average acceleration components Vx, Vy, Vz described above. The fluctuation range Vg is calculated (step S364). Then, by determining whether or not the fluctuation range Vg is smaller than the predetermined threshold Thg, the processor 21 determines whether or not the movement of the subject P1 has become smaller due to the transition to the sleep state (step S365). .

  When the fluctuation range Vg calculated in step S364 is smaller than the threshold value Thg, the processor 21 executes the processes of steps S366 and S367 according to the affirmative determination route of step S365. In step S366, the processor 21 determines that the upper body of the subject P1 has shifted to the “sleep state”, and then the processor 21 proceeds to the process of step S344 in FIG.

  On the other hand, when the fluctuation range Vg calculated in step S364 is larger than the threshold Thg, the processor 21 proceeds to the process of step S344 of FIG. 13 after executing the process of step S363 according to the negative determination route of step S365.

  In step S344 illustrated in FIG. 13, the processor 21 determines whether or not the state of the subject P1 has shifted to the “sleep state” based on the determination result obtained in the process of step S343.

  When the determination result that the “before sleep” state is continued is obtained by the process of step S343 described above, the processor 21 returns to the process of step S342 according to the negative determination route of step S344. Then, the processor 21 repeats the process of executing the process of step S343 based on the newly acquired measurement value of the acceleration sensor 19.

  In the process of repeating the process from step S342 to step S344, when the determination result that the state of the subject P1 has shifted to the sleep state is obtained by the process of step S343, the processor 21 follows the affirmative determination route of step S344. move on.

  In the affirmative determination route of step S344, the processor 21 first sets “sleeping” as the state of the subject and sets the inspiratory state as the initial state of the respiratory state (step S345). At this time, the processor 21 sets an initial value 0 to the sleep interruption time Ts used in the processing described later. Next, the processor 21 starts power supply from the battery 34 to the angular velocity sensor 11 by operating the switch 35 included in the sensor unit 30 illustrated in FIG. 12 via the sensor interface 28 (step S346). As described above, in the affirmative determination route of step S344, the processor 21 executes the process of step S346, thereby realizing the function of starting the power supply to the angular velocity sensor 11 by the power control unit 32 illustrated in FIG. can do.

  Thereafter, the processor 21 executes a respiration measurement process based on the measurement values gy and gx of the angular velocity sensor 11 including the processes of steps S302 to S312 illustrated in FIG. 7 (step S314).

  Next, the processor 21 again acquires the measurement values αx, αy, αz from the acceleration sensor 19 in the same manner as in step S342 described above (step S347). Then, this time, based on these measured values αx, αy, αz, the processor 21 executes processing for determining the continuation of the sleep state described later (step S348).

  When the determination result that the sleep state of the subject P1 is continued is obtained by the process of step S348, the processor 21 returns to the process of step S314 according to the affirmative determination route of step S349. Then, the processor 21 repeats the process of executing the respiration measurement process based on the newly acquired measurement value of the angular velocity sensor 11 and the process of determining the continuation of the sleep state based on the newly acquired measurement value of the acceleration sensor 19.

  In the process of repeating Step S314 and Steps S347 to S349, when the determination result that the sleep state of the subject P1 is not continued is obtained by the process of Step S348, the processor 21 negates Step S349. Proceed to the decision route.

  In the negative determination route in step S349, the processor 21 first sets “wake up” as the state of the subject (step S350). Further, the processor 21 stops the power supply from the battery 34 to the angular velocity sensor 11 by operating the switch 35 described above via the sensor interface 28 (step S351). As described above, the processor 21 executes the process of step S351 in the negative determination route of step S349, thereby realizing the function of the power control unit 32 illustrated in FIG. 10 stopping the power supply to the angular velocity sensor 11. be able to. Thereafter, the processor 21 ends the process.

  Here, after the subject P1 falls asleep, the subject P1 may stand in the toilet or drink water. At this time, the posture of the subject P1 temporarily rises on the bed or stands upright.

  In consideration of such a case, the subject P1 enters the “wake-up state” only when the period in which the posture of the subject P1 is upright or is standing on the bed continues for a predetermined time Ths or more. A method for detecting the transition will be described below.

  FIG. 15 shows an example of a flowchart of processing for determining the continuation of the sleep state. Each step illustrated in FIG. 15 is an example of a process for determining the continuation of the sleep state illustrated in step S348 in FIG. 13, and an example of a technique for realizing the determination unit 31 illustrated in FIG. It is.

  Similarly to step S361 described above, the processor 21 determines the average direction in which the gravitational acceleration has worked during this period based on the measurement values αx, αy, αz obtained by the acceleration sensor 19 during the acquisition interval τr. Is obtained (step S371). For example, the processor 21 calculates the average acceleration components Vx, Vy, Vz indicating the average direction in which the gravitational acceleration has worked by averaging the measured values αx, αy, αz at the respective sampling timings. Good.

  Next, the processor 21 determines whether or not the directions indicated by the average acceleration components Vx, Vy, and Vz obtained in step S371 are substantially orthogonal to the z-axis direction in the same manner as in step S362 described above (step S362). S372). For example, when the average acceleration component Vz in the z-axis direction obtained in step S371 exceeds a predetermined threshold, the processor 21 determines that the direction in which the gravitational acceleration works is not orthogonal to the z-axis direction corresponding to the spine of the subject P1. (No determination in step S372).

  In the negative determination route in step S372, the processor 21 first obtains the measured values αx, αy, αz of the acceleration sensor 19 at the sleep interruption time Ts indicating the period in which the sleep of the subject P1 is temporarily interrupted. Are added (step S373). Next, the processor 21 determines whether or not the sleep interruption time Ts after the addition is longer than the predetermined time Ths described above (step S374).

  When the sleep interruption time Ts is equal to or shorter than the predetermined time Ths (negative determination in step S374), the processor 21 proceeds to the process of step S375 while maintaining the sleep interruption time Ts. In step S375, the processor 21 determines that the state of the subject P1 continues the “sleep state”, and then proceeds to the process of step S349 in FIG.

  As described above, the process of step S348 in FIG. 13 is repeated at every acquisition interval τr of the measured values αx, αy, αz of the acceleration sensor 19 as long as an affirmative determination is made in step S349. Therefore, each time the processor 21 proceeds according to the affirmative determination route of step S372 described above, the sleep interruption time Ts increases due to the acquisition interval τr accumulated for each repetition process. Thus, when the sleep interruption time Ts becomes longer than the predetermined time Ths (affirmative determination in step S374), the processor 21 determines that the state of the subject P1 has shifted to the “wake-up state” (step Thereafter, the process proceeds to step S349 in FIG.

  In this way, when the subject P1 has stood up on the bed or maintained an upright state for a predetermined time or more, it is determined that the subject P1 has detected the transition to the “wake-up state”. The result can be returned to the process of step S349 in FIG.

  On the other hand, the subject P1 may lie down on the bed again in the process in which the processes in steps S314 and S347 to S349 in FIG. 13 are repeated. In this case, since the direction of the gravitational acceleration obtained based on the measured values αx, αy, αz of the acceleration sensor 19 in step S371 shown in FIG. 14 is substantially perpendicular to the z-axis, the processor 21 performs step S372. The process of the affirmative determination route is executed.

  In the affirmative determination route of step S372, the processor 21 first sets an initial value 0 again to the sleep interruption time Ts (step S377). Thereafter, the processor 21 determines that the state of the subject P1 is continuing the “sleep state”, and then proceeds to the process of step S349 of FIG.

  As described with reference to FIG. 15, according to the respiratory measurement device 10 to which the process for determining the continuation of the sleep state of the subject P1 is applied, the respiratory measurement is performed even when the sleep state of the subject P1 is temporarily interrupted. Processing can be continued.

  The reason why the human rhythm of breathing is disturbed is mainly during unconscious sleep, and as described above, a technique for selectively measuring breathing during a period in which the subject P1 is in a sleep state is useful. .

  Next, a method for detecting sleep apnea with high accuracy by using the respiration measurement method of the present disclosure will be described.

  FIG. 16 shows an embodiment of the sleep apnea detection device 40. Note that among the constituent elements shown in FIG. 16, those equivalent to the constituent elements shown in FIG. 10 are denoted by the same reference numerals, and description thereof is omitted. The sleep apnea detection device 40 illustrated in FIG. 16 is also another embodiment of the respiratory measurement device disclosed herein.

  The sleep apnea detection device 40 illustrated in FIG. 16 includes a first determination unit 41, a second determination unit 42, a power control unit 43, in addition to the units included in the respiratory measurement device 10 illustrated in FIG. , And a detection unit 44.

  Measurement values αx, αy, αz obtained by the acceleration sensor 19 are input to the first determination unit 41 and the second determination unit 42 illustrated in FIG. The first determination unit 41 determines whether or not the subject P1 is in a sleep state based on the measurement values αx, αy, and αz of the acceleration sensor 19 in the same manner as the determination unit 31 illustrated in FIG. Further, the second determination unit 42 determines whether or not the posture of the subject P1 is the supine position based on the measurement values αx, αy, and αz of the acceleration sensor 19.

  Further, the power control unit 43 controls power supply to the angular velocity sensor 11 based on the determination results by the first determination unit 41 and the second determination unit 42. For example, when the first determination unit 41 determines that the subject P1 is in a sleeping state and the second determination unit 42 determines that the posture of the subject P1 is in the supine position, Control for supplying driving power to the angular velocity sensor 11 is performed.

  Based on the measurement values gy and gx obtained from the angular velocity sensor 11 during the period when the driving power is supplied to the angular velocity sensor 11, the integration unit 12, the calculation unit 13, and the collection unit 14 determine these measurement values gy. , Respiration measurement processing based on gx is performed. And based on the information collected by the collection part 14 in this process, the detection part 44 detects the information which shows signs, such as the sleep apnea syndrome which appeared in the test subject's P1 respiratory rhythm.

  Here, when the apnea state due to sleep apnea syndrome or the like occurs when the subject P1 is in the sleeping position in the supine position, the upper airway is blocked due to the root of the tongue of the subject P1 dropping. There is. On the other hand, when the subject P1 is sleeping in the lateral position, the upper airway is hardly blocked by the root portion under the subject P1.

  That is, in the sleep apnea detection device 40 illustrated in FIG. 16, the period during which the power control unit 43 supplies driving power to the angular velocity sensor 11 according to the determination results by the first determination unit 41 and the second determination unit 42. Corresponds to a period during which the subject P1 has a high risk of falling into an apneic state.

  As described above, by supplying power to the angular velocity sensor 11 only during a period during which the subject P1 has a high risk of falling into an apnea state, and performing respiratory measurement based on the measurement value of the angular velocity sensor 11 only during this period, sleep Power saving of the hour apnea detection device 40 can be achieved.

  Furthermore, since the sleep apnea detection device 40 illustrated in FIG. 16 includes the respiratory measurement device 10 of the present disclosure, the respiratory motion of the subject P1 is measured with high accuracy regardless of the mounting position of the angular velocity sensor 11. It is possible.

  The sleep apnea detection device 40 illustrated in FIG. 16 can also be realized using a computer device such as a personal computer.

  FIG. 17 shows another example of the hardware configuration of the sleep apnea detection device 40. Note that, among the components shown in FIG. 17, components equivalent to those shown in FIG. 12 are denoted by the same reference numerals and description thereof is omitted.

  The computer apparatus 20 illustrated in FIG. 17 includes an output interface 29 in addition to the units illustrated in FIG. The output interface 29 is connected to the processor 21 via a bus, as with other units included in the computer device 20.

  Further, the sleep apnea detection device 40 illustrated in FIG. 17 includes output devices such as the output interface 29 and the speaker 45 described above, in addition to the components illustrated in FIG. 12. The speaker 45 is connected to the computer apparatus 20 via the output interface 29, and the processor 21 can output a desired alarm sound or the like via the output interface 29 and the speaker 45. Note that the output device connected via the output interface 45 is not limited to the speaker 45, and may send a message to, for example, a nurse call system (not shown).

  FIG. 16 illustrates that the processor 21 controls the power supply from the battery 34 to the angular velocity sensor 11 by operating the switch 35 provided in the sensor unit 30 illustrated in FIG. 17 via the sensor interface 28. This is an example of a method for realizing the power control unit 43.

  The memory 22 illustrated in FIG. 17 stores an application program for causing the processor 21 to execute processing for detecting sleep apnea together with the operating system of the computer device 20. The application program for processing for detecting sleep apnea includes an application program for causing the processor 21 to execute processing for determining a sleep state, processing for controlling power supply, and respiration measurement processing. The application program for detecting sleep apnea can also be recorded and distributed on a recording medium such as the removable disk 27, for example. Then, the application program for detecting the sleep apnea may be stored in the memory 22 and the hard disk device 23 by attaching the removable disk 27 to the optical drive device 26 and performing a reading process. Further, the application program for detecting sleep apnea can be read into the memory 22 and the hard disk device 23 via a communication device (not shown) connected to a network such as the Internet.

  In addition, the processor 21 includes the first determination unit 31 and the power control unit 32 illustrated in FIG. 16 by executing the application program for detecting the sleep apnea stored in the memory 22 as described above. The function of the respiratory measurement device 10 can be achieved.

  FIG. 18 shows an example of a flowchart of sleep apnea detection processing. Of the steps shown in FIG. 18, the same steps as those shown in FIG. 13 are denoted by the same reference numerals and description thereof is omitted.

  The process of each step shown in FIG. 18 is an example of a process included in the application program for the sleep apnea detection process described above. Further, the processing of these steps is executed by the processor 21.

  In the flowchart shown in FIG. 18, the processor 21 executes a process of determining the posture of the subject P1 during sleep together with whether or not the subject P1 has entered the sleeping state instead of step S343 shown in FIG. 13 (step S381). ).

  FIG. 19 shows an example of a flowchart of processing for determining the transition to the sleep state and the posture during sleep. Of the steps shown in FIG. 19, the same steps as those shown in FIG. 14 are denoted by the same reference numerals, and description thereof is omitted.

  The process of each step illustrated in FIG. 19 is an example of the process of step S381 illustrated in FIG. The processing in each of these steps is an example of a technique for realizing the functions of the first determination unit 41 and the second determination unit 42 illustrated in FIG.

  In the affirmative determination route of step S365 in the flowchart shown in FIG. 18, the processor 21 determines that the state of the subject P1 has shifted to the “sleep state” in step S366, and then the direction of gravitational acceleration is the x-axis direction. It is determined whether or not (step S388). For example, the processor 21 determines whether the direction of gravitational acceleration is in the x-axis direction based on whether the average acceleration component Vx in the x-axis direction calculated in step S361 is larger than a predetermined threshold. May be. For this threshold value, for example, a value obtained as the average acceleration component Vx may be set when the direction of gravitational acceleration substantially coincides with the x-axis direction. As described above, the processor 21 performing the determination process of step S388 in the affirmative determination route of step S365 is an example of a technique for realizing the function of the second determination unit 42 illustrated in FIG.

  When the average acceleration component Vx in the x-axis direction obtained in step S361 is larger than the threshold value described above, the processor 21 performs a process of setting the posture of the subject P1 to the supine position according to the affirmative determination route of step S388 ( Step S389). After that, the processor 21 ends the process of determining the transition to the sleeping state and the sleeping posture, and proceeds to the process of step S382 in FIG.

  On the other hand, when the average acceleration component Vx in the x-axis direction calculated in step S361 is equal to or less than the above-described threshold, the processor 21 continues to enter the sleep state and sleep posture according to the negative determination route in step S388. The process of determining is terminated. Then, the processor 21 proceeds to the process of step S382 in FIG.

  In step S382, the processor 21 determines that the subject P1 has shifted to the sleeping state by the process of step S381 described above, and further determines whether the posture is set to the supine position. Then, only when the subject P1 is sleeping in the supine position, the processor 21 proceeds to the affirmative determination route of step S382 and executes the subsequent processing.

  In the process of repeating steps S314 and S347 to S349 in the affirmative determination route of step S382, the processor 21 collects information indicating a sign of sleep apnea based on the information collected in this process.

  For example, the processor 21 performs sleep apnea based on the time tb from the change point to the previous inspiratory state or the time te from the change point to the previous exhalation state described in the flowcharts of FIGS. 8 and 9. May be detected.

  In the flowchart illustrated in FIG. 18, the processor 21 has a time tb from the change point to the previous inhalation state or a time te from the change point to the last exhalation state obtained in the process of step S314 exceeds 10 seconds. Whether or not (step S384). The time tb from the change point to the previous inspiratory state and the time te from the change point to the previous exhalation state both indicate the elapsed time from the change point of the respiratory state. And that the elapsed time from the change point of the breathing state exceeds 10 seconds is nothing but that the apnea time exceeds 10 seconds. Therefore, the processor 21 can implement the function of the detection unit 44 that detects the apnea period based on the information obtained by the collection unit 14 illustrated in FIG. 16 by executing the process of step S384.

  The processor 21 can further collect information that can be used for diagnosis of sleep apnea syndrome and the like in the affirmative determination route of step S384 described above.

  For example, in step S385 included in the affirmative determination route of step S384, the processor 21 may execute a process of recording the apnea time detected as described above and a process of counting the apnea frequency Nb.

  FIG. 20 shows an example of a flowchart of apnea time recording processing and apnea count counting processing. The process of each step illustrated in FIG. 20 is an example of the process of step S385 illustrated in FIG. The processing in each of these steps is an example of a method for realizing the function of the detection unit 44 illustrated in FIG.

  First, the processor 21 acquires the number of breaths and the breathing state obtained in the immediately preceding step S314 (step S391). Next, the processor 21 determines whether or not the number of breaths and the breathing state acquired in step S391 are the same as the number of breaths and the breathing state acquired last time (step S392).

  If the previously acquired respiratory frequency or respiratory state does not match the newly acquired respiratory frequency or respiratory state (negative determination in step S392), the processor 21 determines that a new apnea time has been detected.

  In this case, the processor 21 records the newly detected apnea time, and adds a numerical value 1 to the apnea count Nb (step S393). Next, the processor 21 stores the new breathing number and breathing state acquired in step S391 as information indicating the previous breathing number and breathing state to be referred to in subsequent processing (step S394).

  On the other hand, when the previously acquired number of breaths and breathing state match the newly acquired number of breaths and breathing state (affirmative determination in step S392), the processor 21 determines that the apnea time has continued. To do.

  In this case, the processor 21 uses the latest apnea time recorded in the process of step S393 as the elapsed time tb, te from the change point of the respiratory state that is the target of the comparison process in step S384 of FIG. (Step S395).

  As described above, the detection unit 44 included in the sleep apnea detection device 40 of the present disclosure uses the respiration measurement result based on the measurement values gy and gx of the angular velocity sensor 11 attached to the chest of the subject P1, and uses the respiration measurement result of the subject P1. Information about sleep apnea can be collected.

  Here, as described in the description of the embodiment of the respiration measurement device 10 described above, the respiration measurement device 10 of the present disclosure increases the movement of the chest associated with the respiration of the subject P1 from the measurement values gy and gx of the angular velocity sensor 11. It can be measured with accuracy. Therefore, the processor 21 acquires the apnea frequency Nb and the apnea time with high accuracy by performing the processing of steps S391 to S395 described above based on the measurement result, and provides the processing to step S386 of FIG. be able to.

  In step S386, the processor 21 determines whether or not the state of the subject P1 is an alarm target based on the apnea frequency Nb or the apnea time updated in the process of step S385. For example, the processor 21 determines that the subject P1 is in a dangerous state when the apnea frequency Nb exceeds a predetermined threshold or when the apnea time exceeds another predetermined threshold in the process of step S386. Judgment may be made and it may be determined that the object is alarm.

  When the processor 21 determines that the state of the subject P1 is an alarm target (positive determination in step S386), for example, the processor 21 may cause the speaker 45 to output an alarm sound via the output interface 29 illustrated in FIG. (Step S387). Thereafter, the processor 21 ends the sleep apnea detection process.

  On the other hand, when the state of the subject P1 is not an alarm target (negative determination in step S386), the processor 21 proceeds to the process of step S347 as in the negative determination route of step S384. Then, the processor 21 continues the sleep apnea detection process by monitoring the breathing motion of the subject P1.

  As described above, according to the apnea detection device 40 of the present disclosure, the accuracy of the sleep apnea of the subject P1 using the respiration measurement result based on the measurement values gy and gx of the angular velocity sensor 11 attached to the chest of the subject P1. High information can be collected. In addition, by applying the power supply control process described above, the apnea detection device 40 according to the present disclosure provides high-precision information regarding sleep apnea of the subject P1 when there is a high possibility that sleep apnea will occur. Can only be acquired. This makes it possible to achieve both the power saving performance of the sleep apnea detection device 40 and high detection performance.

  The respiratory measurement device 10 of the present disclosure is not limited to the sleep apnea detection device 40 illustrated in FIG. 16, and is a device that detects the apnea state of the subject P1 by constantly measuring the breathing state of the subject P1. It can also be applied to.

  For example, an apnea detection device that combines the respiratory measurement device 10 illustrated in FIG. 1 and the detection unit 44 illustrated in FIG. 16 can be realized. As described above, the angular velocity sensor 11 included in the respiration measurement device 10 of the present disclosure can be disposed together with a sensor for acquiring an electrocardiogram, for example, and therefore, can be applied to respiration monitoring of a newborn. Is also possible.

DESCRIPTION OF SYMBOLS 10 ... Respiration measuring device; 11 ... Angular velocity sensor; 12 ... Integration part; 13 ... Calculation part; 14 ... Collection part; 15 ... Noise removal part; ... acceleration sensor; 21 ... processor; 22 ... memory; 23 ... hard disk drive (HDD); 24 ... display device; 25 ... input device; 26 ... optical drive device; 27 ... removable disk; 28 ... sensor interface; 30 ... Sensor unit; 31 ... Determination unit; 32, 43 ... Power control unit; 34 ... Battery; 35 ... Switch; 40 ... Sleep apnea detection device; 41 ... First determination unit; 44 ... detecting unit; 45 ... speaker

Claims (6)

A first measurement value indicating a first angular velocity of a motion rotating in a first plane that coincides with or is perpendicular to a plane including the back surface of the subject, from an angular velocity sensor attached to the chest or upper abdomen of the subject lying down ; Obtaining a second measurement value indicating a second angular velocity of the movement rotating in the second plane orthogonal to the first plane;
By integrating the first measurement value and the second measurement value, the neck of the subject in a straight line connecting the neck of the subject with respect to the second plane and the first projection of the angular velocity sensor onto the first plane. A first rotation angle with the origin as the origin and a second straight line with the subject's neck as the origin connecting the neck of the subject with respect to the first plane and the second projection of the angular velocity sensor onto the second plane. Find each rotation angle,
Based on the first rotation angle and the second rotation angle, the origin is the neck of the subject that is a straight line connecting the neck of the subject and the angular velocity sensor with respect to the first plane or the second plane . Calculate the rotation angle,
The respiratory measurement method characterized by collecting information indicating movement of the chest associated with breathing of the subject from the time change of the third rotation angle. An angular velocity sensor attached to the chest or upper abdomen of the subject in a lying state, the first measurement value indicating a first angular velocity of a motion rotating in a first plane that coincides with or is perpendicular to a plane including the back surface of the subject; An angular velocity sensor that outputs a second measurement value indicating a second angular velocity of a motion rotating in a second plane orthogonal to the first plane;
By integrating the first measurement value and the second measurement value, the neck of the subject in a straight line connecting the neck of the subject with respect to the second plane and the first projection of the angular velocity sensor onto the first plane. A first rotation angle with the origin as the origin and a second straight line with the subject's neck as the origin connecting the neck of the subject with respect to the first plane and the second projection of the angular velocity sensor onto the second plane. Integration units for determining the rotation angles respectively;
Based on the first rotation angle and the second rotation angle, the origin is the neck of the subject that is a straight line connecting the neck of the subject and the angular velocity sensor with respect to the first plane or the second plane . A calculation unit for calculating a rotation angle;
A respiratory measurement apparatus comprising: a collection unit that collects information indicating movement of the chest associated with breathing of the subject from time variation of the third rotation angle. In the respiratory measurement apparatus according to claim 2,
The first measurement value indicates a first angular velocity of a motion in which the first projection of the angular velocity sensor on the first plane rotates around the neck of the subject,
The second plane is a plane including the spine of the subject;
It said second measurements, respiratory measuring device, characterized in that shows the second angular velocity of the movement which the second projection of the angular velocity sensor to the second plane is rotated as a fulcrum neck of the subject. In the respiratory measurement apparatus according to claim 2,
The integration unit performs integration on the first measurement value and the second measurement value after removing noise components including a high frequency component and a drift component from the first measurement value and the second measurement value, respectively.
The collection unit collects information indicating the breathing cycle of the subject by analyzing the time change of the third rotation angle after smoothing the time change of the third rotation angle. Measuring device. In the respiratory measurement apparatus according to claim 2,
An acceleration sensor attached to the trunk of the subject;
A determination unit that determines whether the subject is in a sleep state based on a measurement value obtained by the acceleration sensor;
A respiratory measurement device comprising: a power control unit that supplies drive power to the angular velocity sensor over a period in which the determination unit determines that the subject is sleeping. In the respiratory measurement apparatus according to claim 2,
An acceleration sensor attached to the trunk of the subject;
A first determination unit that determines whether or not the subject is in a sleep state based on a measurement value obtained by the acceleration sensor;
A second determination unit that determines whether or not the posture of the subject is in a supine position based on a measurement value obtained by the acceleration sensor;
The period during which the subject is determined to be sleeping by the first determination unit and the period in which the subject is determined to be supine by the second determination unit. A power control unit for supplying driving power to the angular velocity sensor;
A detection unit that detects, as an apnea period, a period in which the movement of the chest associated with breathing of the subject has stopped for a predetermined period or longer based on information obtained by the collection unit. Respiratory measurement device.

Images