JP2004024684A - Testing apparatus of apnea syndrome - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a testing apparatus of an apnea syndrome which precisely discriminates a low respiratory condition in addition to a respiratory standstill condition. <P>SOLUTION: This testing apparatus A generates change in a load corresponding to body motion obtained by respiration of a sleeping person, and discriminates the respiratory standstill condition or the low respiratory condition of the sleeping person on the basis of the change in a frequency of this respiratory signal. Since recovering respiratory operation made after the respiratory standstill condition or the low respiratory condition is faster than normal respiration, occurrence of the respiratory standstill condition or the low respiratory condition is precisely discriminated from the change in the frequency of the respiratory signal corresponding to the velocity of respiratory operation as mentioned before. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to an apnea syndrome testing apparatus for testing a sleep apnea state or a hypopnea state due to sleep apnea syndrome.
[0002]
[Prior art]
2. Description of the Related Art As a conventional inspection apparatus for an apnea state due to sleep apnea syndrome, for example, there is an apparatus described in JP-A-2001-37742.
[0003]
This conventional apparatus includes a sensor sheet having a plurality of pressure-sensitive elements inserted under the bedding, a controller, and a monitor for displaying the respiratory rate of the sleeping person, the number of times of decrease in blood oxygen saturation, and the like. The controller generates a respiratory motion signal, which is a signal component in a frequency band corresponding to the respiratory rate of the sleeping person, from the load signal output from each pressure-sensitive element. From the change pattern of the amplitude of the respiratory body motion signal, a decrease in blood oxygen saturation occurring during obstructive apnea is determined, and the number of times of decrease in blood oxygen saturation is displayed on a monitor.
[0004]
For example, in an obstructive apnea condition in which the throat is obstructed due to relaxation of the throat muscles during sleep and oxygen is not supplied to the lungs, the sleeper breathes, but oxygen is supplied to the lungs due to obstruction of the throat. Not done. Then, when oxygen is not supplied to the lungs and the blood oxygen saturation level decreases to reach a predetermined low concentration level, the sleeper temporarily wakes up and performs a very deep breathing operation. For this reason, in the conventional apparatus, it is determined that the amplitude of the respiratory body motion signal has sharply increased, and it is determined that the state is an obstructive apnea state and, consequently, a decrease in blood oxygen saturation.
[0005]
[Problems to be solved by the invention]
Here, in sleep apnea syndrome, in addition to obstructive apnea and central apnea in which oxygen is not supplied to the lungs at all, the airway of the sleeping person is narrowed, and the supply of oxygen is insufficient. There is also hypopnea. Also in the case of hypopnea, the patient may experience symptoms similar to obstructive apnea, due to a lack of oxygen supply during sleep. Therefore, an apnea syndrome testing apparatus is required to be capable of testing hypopnea as well as apnea.
[0006]
However, when the apnea state is determined by catching the sudden increase in the amplitude of the respiratory body motion signal as in the conventional apparatus, in the hypopnea state, the amplitude change of the respiratory body motion signal is as large as the apnea state. Since it may not occur, the low respiratory state cannot be determined with high accuracy.
[0007]
In this case, if the threshold of the amplitude change for determining the hypopnea state is set small in order to detect the hypopnea state from the amplitude change of the respiratory body motion signal, for example, the respiratory change due to the tremor of the body is mistaken for the hypopnea state. In some cases, the determination may be made, and the detection accuracy of the hypopnea state cannot be improved.
[0008]
The present invention has been made in view of such a conventional problem, and has as its object to provide an apnea syndrome testing apparatus capable of determining a hypopnea state in addition to an apnea state with high accuracy. .
[0009]
[Means for Solving the Problems]
An apnea syndrome testing apparatus according to claim 1, wherein the respiratory signal generating means for generating a change in load applied to the bedding as a respiratory signal in accordance with a body motion caused by respiration of a sleeping person, and a change in the frequency of the respiratory signal. Determining means for determining whether the sleeping person is in an apnea state or a hypopnea state.
[0010]
When an apnea state or a hypopnea state occurs, it is common that a recovery breathing operation is performed in order to compensate for the insufficient oxygen supply. However, in the case of the apnea state, since the recovery breathing operation stronger than the hypopnea state is often performed, it is difficult to detect both the apnea state and the hypopnea state with high accuracy from the change state of the amplitude of the respiratory signal. Have difficulty.
[0011]
The inventor of the present invention has found that there is a difference in the strength of the recovery breathing operation performed in the apnea state and the hypopnea state, but in both recovery breathing operations, the respiration speed is compared with the normal respiration speed. And noticed that it was clearly faster. For this reason, the test apparatus according to claim 1 determines the apnea state or the hypopnea state of the sleeping person based on the change in the frequency of the respiration signal. The frequency of the breathing signal corresponds to the speed of the breathing movement. Therefore, the occurrence of apnea or hypopnea is determined with high accuracy based on the fact that the frequency of the breathing signal has changed from a low frequency to a high frequency or the frequency of the breathing signal has changed from a high frequency to a low frequency. be able to.
[0012]
As described in claim 2, the determination means also monitors a change in the amplitude of the respiratory signal, wherein the amplitude of the respiratory signal decreases, and then the amplitude of the respiratory signal increases, and When the frequency of the respiratory signal when the amplitude increases, the frequency of the respiratory signal at the time of the decrease, the amplitude lowering state of the respiratory signal and the apnea state or hypopnea state of the sleeping person. It is preferable to determine.
[0013]
After the apnea state and the hypopnea state, a recovery breathing operation is performed. Accordingly, by determining the change from the apnea state or the hypopnea state to the recovery breathing operation using both the change in the frequency of the respiratory signal and the change in the amplitude of the respiratory signal, the determination of the apnea state or the hypopnea state is made. Accuracy can be further improved.
[0014]
As described in claim 3, it is preferable that the determination means calculates an average value of a plurality of amplitudes in the respiration signal, and determines a change in the amplitude of the respiration signal from a difference between the average values.
[0015]
In this way, for example, as in the case of periodic limb movement, the noise component acts on the respiratory signal sporadically, and even when the amplitude of the respiratory signal increases, the noise component can be attenuated. Accuracy of determination regarding a change in signal amplitude can be improved.
[0016]
As described in claim 4 and claim 5, when the change ratio of the amplitude of the respiratory signal is 1.4 or more, the determination unit changes the amplitude of the respiratory signal from a reduced state to an increased state. It is preferable to determine that the frequency of the respiratory signal has changed from a low frequency to a high frequency when the cycle of the respiratory signal is shortened by 0.5 s or more. This is because it has been confirmed that the apnea state or the hypopnea state can be determined with extremely high accuracy by using the above-described threshold value in an actual test result for the subject.
[0017]
As described in claim 6, when the period during which the amplitude of the respiratory signal increases and the frequency increases is shorter than a predetermined period, the determination unit determines the apnea state or the hypopnea state. Preferably not.
[0018]
This is to prevent erroneous determination due to noise components such as the periodic limb movement described above.
[0019]
As described in claim 7, it is preferable that the determination means includes a calculation means for calculating the number of times that the sleeping person has determined that the sleeping person is in the apnea state or the hypopnea state. Thereby, the occurrence state of the apnea state or the hypopnea state can be easily grasped.
[0020]
As described in claim 8, there is provided a discriminating means for discriminating between an apnea state and a hypopnea state based on the relationship of the phase of the load change according to the body movement due to respiration in the chest and abdomen of the sleeping person. Is preferred. If the apnea state and the hypopnea state can be distinguished from each other, it is possible to take appropriate measures for the symptoms. In addition, as a specific discriminating method between the apnea state and the hypopnea state, as described in claim 9, the phase of the load change in the chest and abdomen of the sleeping person according to the body movement due to respiration is substantially. When the phases are the same, it is determined to be a hypopnea state, and when the phases are substantially opposite, it is determined to be an apnea state.
[0021]
As described in claim 10, it is preferable to include a sleeping form determining unit that determines a sleeping state of the sleeping person based on a load distribution of the sleeping person in the bedding. This is because if the sleeping state in which the apnea state or the hypopnea state occurs can be specified, it becomes useful information at the time of treatment. Therefore, as described in claim 11, it is preferable that the calculating means calculates the number of times of the apnea state or the hypopnea state for each sleeping state determined by the sleeping state determining means.
[0022]
As described in claim 12, it is preferable that the breathing signal generation unit stops generating the breathing signal while the load distribution of the sleeping person on the bedding is changing. While the load distribution in the bedclothes of the sleeping person is changing, the sleeping person is turning over, etc., and is not in a state determined to be apnea or hypopnea, so it is not necessary to generate a breathing signal. It is.
[0023]
As described in claim 13, the apparatus further comprises a bed-separation determining unit that determines the bed-separation of the sleeping person based on a state of a load applied to the bedding, and the breathing signal generation unit includes a bed separation unit. When it is determined that the respiratory signal has been generated, it is desirable to stop the generation of the respiratory signal. This is because an accurate respiratory signal cannot be generated if it is determined that the patient has left the bed.
[0024]
As a specific method of judging the presence or absence of bed, as described in claim 14, when a load is not applied to a predetermined area or more of the bedding, it may be determined that the bed is left, or as described in claim 15. If the load does not change according to the body movement due to the respiration of the sleeping person, it may be determined that the user has left the bed.
[0025]
As described in claim 16, it is preferable that the apparatus further includes a storage unit that stores at least one of a breathing signal by the breathing signal generation unit, a determination result by the determination unit, and a calculation result by the calculation unit. That is, while the sleeping person is asleep, the respiration signal is generated and stored, and thereafter, the apnea state or the hypopnea state may be determined using the stored respiration signal. The determination of the respiratory state or the hypopnea state may be performed and the determination result may be stored, or the number of occurrences of the apnea state or the hypopnea state may be stored. In each case, useful information can be provided to guide treatment. Further, as described in claim 17, the storage means stores the determination result by the determination means, the determination result of the sleeping form by the sleeping form determination means, and the determination result of the presence / absence of bed by the presence / absence determination section. Is also good. Further, as described in claim 18, a notifying means for notifying the information stored in the storage means may be provided.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0027]
FIG. 1 is a diagram showing an installation state when using an apnea syndrome testing apparatus A as an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of the testing apparatus A.
[0028]
As shown in FIG. 1, the bed 1 includes a placing portion 11 for placing a bedclothe 10 such as a mattress, and a back plate portion 12 erected from an end of the placing portion 11. The inspection device A is used by being inserted into the lower part of the bedding 10 installed on the placing portion 11 of the bed 1. In addition, the inspection device A is installed on the side of the back plate portion 12 from the center of the placing portion 11 so as to correspond to the position from the chest to the abdomen of the sleeper when the sleeper lies on the bed 1. You.
[0029]
As shown in FIG. 2, the inspection device A includes a sheet unit 2 and a control unit 3. The sheet unit 2 is configured by sandwiching a plurality of (three in this example) sensor sheets 22 and a sensor selection unit 23 provided for each sensor sheet 22 between two sheet-shaped protection members 21. Have been.
[0030]
The sensor sheet 22 includes a plurality of pressure-sensitive elements 221 (in this example, a total of three sheets, 162) of which pressure resistance elements 221 whose electric resistance changes (decreases) in accordance with an applied load are arranged at substantially equal intervals. . In FIG. 2, illustration of a wiring pattern for electrically connecting each pressure-sensitive element 221 and the sensor selection unit 23 is omitted.
[0031]
That is, when a voltage is applied to the circuit including each pressure-sensitive element 221, the electric resistance of the pressure-sensitive element 221 changes according to the applied load, so that the voltage drop value of the pressure-sensitive element 221 increases and decreases. The applied load can be detected independently for each pressure-sensitive element 221 based on the change in the voltage drop value.
[0032]
The control unit 3 includes an A / D converter 31, a microcomputer 32, a memory 33, and a display unit 34, as shown in the block diagram of FIG. Then, in the control unit 3, the load signals of the respective pressure-sensitive elements 221 of the sensor sheet 22 are sequentially selected by the sensor selection unit 23, and the A / D converter 31 converts the analog load signals into digital values. The obtained value (hereinafter, AD value) is taken into the microcomputer 32. At this time, the microcomputer 32 supplies a switching signal to the sensor selection unit 23 to switch the load signal to be input. By repeating such an operation, the microcomputer 32 periodically takes in the load signals from all the pressure-sensitive elements 221 and stores them in the memory 33.
[0033]
Based on the stored load signal, the microcomputer 32 performs processing according to a procedure described later to generate a respiratory curve (respiratory signal) and to generate an apnea state or a hypopnea state determined based on the respiratory curve. The number of times and the time are output to the display unit 34. The display unit 34 numerically or graphically displays the respiratory curve, the number of times of occurrence of the apnea or hypopnea, and the time.
[0034]
With the above configuration, it is possible for a sleeping person to check for a respiratory disorder due to apnea syndrome, such as an unrecognizable sleep apnea or hypopnea, without wearing a special sensor directly on the body. Become.
[0035]
Next, the operation of the inspection apparatus A will be described with reference to the control flowcharts of FIGS. 4 to 8 and the waveform diagrams of FIGS.
[0036]
The control flowchart of FIG. 4 is based on the assumption that all the sensor signals (load signals) detected by the respective pressure-sensitive elements 221 are stored in the memory 33 when the sleeping person is sleeping. This is to generate a respiratory curve according to the body movement caused by the sleeping person's breathing. However, it is of course possible to generate the respiration curve in synchronization with the detection of the sensor signal.
[0037]
First, in step S10, the sensor signals output by each pressure-sensitive element 221 are sequentially read. In step S11, based on the read sensor signal, it is determined whether or not there is any body motion that changes the sleeping state of the sleeping person. This is because it is difficult to generate a respiration curve corresponding to the body motion due to respiration from the sensor signal when such a body motion occurs. Therefore, when it is determined that there is a body movement, the process returns to step S10, and a new sensor signal is read from the sensor signals that are periodically detected and stored. The body movement determination is performed according to the body movement determination flow shown in FIG. 5, and the description will be given later.
[0038]
If it is determined in step S11 that there is no body movement, the process proceeds to step S12, where fast Fourier transform (FFT) is performed to analyze the frequency of the sensor signal of each pressure-sensitive element 221. Next, in step S13, a plurality of pressure-sensitive elements 221 that detect a load change in accordance with body movement due to respiration are extracted based on the magnitude of the power spectrum in the respiration frequency component (0.2 to 0.5 Hz). .
[0039]
Next, in step S14, the pressure sensor 221 having the largest power spectrum in the respiratory frequency component region (that is, the largest load change due to body movement due to respiration) is specified, and the reference sensor for determining the phase difference is used. I do.
[0040]
Next, in step S15, the phase difference between the sensor signals output from the reference sensor and the sensor signal output from the pressure-sensitive element 221 that detects a change in load according to the body movement due to breathing is determined. At this time, a signal having a phase difference within a range of − ／ π to ４π with respect to the sensor signal output from the reference sensor is defined as an in-phase signal. In addition, a signal having a phase difference within a range of 3 / 4π to −3 / 4π with respect to the load signal output by the reference sensor is defined as an opposite-phase signal. Note that signals having other phase differences are not used for calculating the respiration curve.
[0041]
In step S16, the sensor signal from the pressure-sensitive element 221 that outputs an in-phase signal to the reference sensor is added as it is to the sensor signal of the reference sensor, and an opposite-phase signal is output to the reference sensor. The sensor signals of the pressure-sensitive elements 221 to be added are added after phase inversion. Then, in step S17, a respiration curve is obtained by adding all the sensor signals of the reference sensor, the pressure-sensitive element that outputs an in-phase signal, and the sensor signal of the pressure-sensitive element that outputs an opposite-phase signal.
[0042]
In step S18, the presence / absence determination for determining whether or not the sleeping person is present is performed. This is because the accuracy of the determination of the apnea state or the hypopnea state is improved by adopting the respiration curve for determining the apnea state or the hypopnea state only during bedtime. Therefore, if it is determined in step S18 that the patient has left the bed, the respiration curve derived in step S17 is deleted from the data output to the apnea analysis flow. The determination of the presence or absence of a bed is made in accordance with the presence / absence of bed determination flow shown in FIG.
[0043]
In step S19, the same body movement determination as in step S11 is performed on the sensor signal read in step S22 described below. When it is determined that there is a body movement, the process returns to step S10, a new sensor signal is read, and the body movement is determined again in step S11. That is, while it is determined that there is a body motion, the read sensor signal is not used as a sensor signal for creating a respiratory curve for determining an apnea state or a hypopnea state. Thereby, a respiration curve can be created from a sensor signal indicating only a body motion due to respiration without being affected by a body motion such as turning over. On the other hand, if it is determined that there is no body movement in step S19, the sleeping state of the sleeping person is determined in step S20. This is because the sleeping state may change the likelihood of an apnea condition or a hypopnea condition, which is useful information for knowing the apnea condition or the hypopnea condition. The determination of the sleeping shape is made according to the sleeping shape determination flow shown in FIG. 7, and the description will be given later.
[0044]
In step S21, the information of the respiration curve created in step S17 is output to the apnea analysis flow described later. In the apnea analysis flow, an apnea state and a hypopnea state are detected based on a respiration curve, and the number of occurrences of the apnea state and the hypopnea state per unit time is calculated.
[0045]
In step S22, a new sensor signal is read. In this case, the above-described reference sensor is not changed unless a body movement such as turning over occurs, so that after reading the load signal, the process returns to step S16.
[0046]
Next, the body movement determination flow will be described with reference to FIG.
[0047]
First, in step S30, a binary image (α) obtained by converting the pressure distribution state of each pressure-sensitive element 221 into a binary image is read from the memory based on whether each pressure-sensitive element 221 detects a load equal to or greater than a predetermined value. . That is, this binary image (α) shows the distribution of the pressure applied to the bedding 10 and the like by the sleeping person. This binary image (α) is updated in step S35 described later and stored in the memory every time a body motion such as turning over occurs.
[0048]
Next, in step S31, the pressure distribution in each pressure-sensitive element 221 is converted into a binary image (β) by comparing the latest sensor signal of each pressure-sensitive element 221 with a predetermined value. Then, in step S32, by comparing the past binary image (α) with the current binary image (β), it is determined whether or not the pressure distribution state in each pressure-sensitive element 221 has changed. In this case, for example, when the number of the pressure sensing elements 221 for detecting the load is different by a predetermined number or more, or when the position of the pressure sensing element 221 for detecting the load is shifted by the predetermined number or more of the pressure sensing elements 221. For example, it is determined that a certain or more change has occurred between the past binary image (α) and the current binary image (β).
[0049]
If it is determined in step S32 that there has been a certain change or more between the past binary image (α) and the current binary image (β), it is set that there is a body motion in step S33. On the other hand, when it is determined in step S32 that there is no change between the past binary image (α) and the current binary image (β), no body motion is set in step S34. If the body motion is set in step S33, the process in step S35 is continuously performed, the past binary image (α) is updated with the current binary image (β), and the updated binary image is updated. (Α = β) is stored in the memory.
[0050]
Next, a flow chart for determining whether or not the user is out of bed will be described with reference to FIG.
[0051]
First, in step S40, among the pressure-sensitive elements 221, the pressure-sensitive elements 221 that detect a load having a magnitude equal to or greater than a certain value are extracted. Then, in a step S41, it is determined whether or not the number of the extracted pressure-sensitive elements 221 is equal to or more than a certain number. Here, when a load is not applied to the bedding 10 by the sleeping person over a predetermined area or more, it is possible to determine that the user has left the bed. Therefore, in step S41, it is determined that the load is applied to the bedding 10 in a predetermined area or more based on the number of the pressure-sensitive elements 221 that detect the load.
[0052]
In step S42, it is determined whether or not the sensor signal of each pressure-sensitive element 221 extracted as the pressure-sensitive element 221 detecting the load changes at the respiration frequency. Even if a certain number or more of the pressure-sensitive elements 221 detect the load, some object other than the sleeping person may be placed on the bedding 10. Therefore, in order to reliably determine whether the sleeping person is in the bed, it is determined whether or not the sensor signal output from the pressure sensing element 221 detecting the load indicates a change in the load due to breathing.
[0053]
Only when it is determined to be “Yes” in steps S41 and S42, the process proceeds to step S44, and it is concluded that the sleeping person is in bed. On the other hand, if “No” is determined in one of steps S41 and S42, it is concluded in step S43 that the sleeping person has left the bed.
[0054]
Next, the sleeping shape determination flow will be described with reference to FIG. The sleeping state is set to a supine or prone position as an initial state.
[0055]
In step S50, a set (x) of sensor values of the pressure-sensitive element 221 to which a load based on the weight of the sleeping person is applied is read from the memory. The set (x) of the sensor values includes both the number of the pressure-sensitive elements 221 to which the load based on the weight of the sleeping person is applied and the load applied to each pressure-sensitive element 221. The set (x) of the sensor values of the pressure-sensitive element 221 is updated in step S58 described later and stored in the memory every time it is determined that the sleeping posture has changed.
[0056]
Next, in step S51, based on the latest sensor signal of each pressure-sensitive element 221, a pressure-sensitive element 221 to which a load based on the weight of a sleeping person is applied is extracted, and a set (y) of the sensor values is obtained. calculate. Next, in step S52, it is determined whether or not the total number of the current load detection pressure-sensitive element sets (y) is larger than a value obtained by multiplying the total number of the past load detection pressure-sensitive element sets (x) by 1.1. . If “Yes” is determined in step S52, since the body area of the sleeping person touching the bedding 10 has increased, the sleeping posture has changed from the lateral position to the supine position or the prone position in step S54. Is set.
[0057]
If “No” is determined in step S52, the process proceeds to step S53, in which the largest sensor signal (maximum value of y) is selected from the sensor set of the pressure-sensitive element 221 that detects the current sleeping person's weight. ) Is selected, and the largest sensor signal (maximum value of x) is similarly selected for the pressure-sensitive element 221 that has detected the weight of a sleeping person in the past. Then, it is determined whether or not the maximum value of y is smaller than a value obtained by multiplying the maximum value of x by 0.8. At this time, if it is determined to be “Yes”, the load per unit area applied to the bedding 10 has been greatly reduced, and it is considered that the sleeping person has changed his sleeping posture from the lateral position to the supine or prone position. Can be Therefore, in step S54, the sleeping state is set to the supine or prone position. If “No” is determined in step S53, the process proceeds to step S55.
[0058]
In step S55, it is determined whether or not the total number of the current load detection pressure-sensitive element sets (y) is smaller than a value obtained by multiplying the total number of the past load detection pressure-sensitive element sets (x) by 0.9. If "Yes" is determined in step S55, the sleeping person's body area in contact with the bedding 10 has decreased, and the sleeping posture has changed from the supine or prone position to the lateral position in step S57. Is set.
[0059]
If “No” is determined in step S55, the process proceeds to step S56, and it is determined whether or not the maximum value of y is larger than the value obtained by multiplying the maximum value of x by 1.2 as described above. At this time, if it is determined to be “Yes”, the load per unit area applied to the bedding 10 has increased greatly, so it is considered that the sleeping person changed his or her lying posture from the supine or prone position to the lateral position. Can be Therefore, in step S57, the sleeping state is set to the lateral position. If “No” is determined in step S56, it is set in step S59 that there is no change in the sleeping form.
[0060]
In step S54 or step S57, when the change of the sleeping posture is set, in step S58, the load detecting pressure-sensitive element group (y) corresponding to the latest sleeping posture is stored in the past load detecting pressure-sensitive element. Substitute into the set (x) to update the load detection pressure-sensitive element set (x).
[0061]
Next, the apnea analysis flow will be described with reference to FIG.
[0062]
In step S60, data for one wavelength of the respiration curve generated by the respiration analysis flow of FIG. 4 is read. Then, in step S61, the read amplitude of one wavelength is calculated.
[0063]
In step S62, the average value of the past three wavelength amplitudes is calculated, and the calculated average amplitude is set to the maximum value. Then, in step S63, the amplitude average having the smallest value among the past 15 amplitude averages is set as the minimum value. An example of the setting of the maximum value and the minimum value is shown in the waveform diagram of FIG.
[0064]
In step S64, it is determined whether or not the maximum value is equal to or greater than a value obtained by multiplying the minimum value by 2.7. At this time, if "Yes" is determined, it is considered that an apnea state or a hypopnea state has occurred immediately before the occurrence of the maximum value, and the count value for counting the number of apnea states is increased by 1 in step S66. Let it.
[0065]
On the other hand, if “No” is determined in step S64, the process proceeds to step S65. In step S65, it is determined whether the maximum value is equal to or greater than a value obtained by multiplying the minimum value by 2.0, and whether the cycle of the respiration curve at the minimum value is longer than a value obtained by adding 0.5 seconds to the cycle at the maximum value. I do. If "Yes" is determined in step S65, it is considered that an apnea state or a hypopnea state has occurred, and the process proceeds to step S66. On the other hand, if “No” is determined in step S65, the process proceeds to step S67.
[0066]
In addition, regarding the determination of the cycle, the cycle of any one wavelength such as the cycle of the latest one wavelength among the respiration curves of the three wavelengths for which the minimum value and the maximum value have been calculated may be compared, or the minimum value and the maximum value may be compared. The average period of the three wavelength periods for which the maximum values have been calculated may be calculated, and the average periods may be compared.
[0067]
In step S67, it is determined whether or not the determination of the apnea state or the hypopnea state has been completed for all the respiratory curves. If the determination has not been made for all the respiratory curves, the process returns to step S60.
[0068]
Finally, in step S68, the number of apnea / low breaths per unit time is calculated based on the count value in the apnea or hypopnea state counted in step S66. The number of apnea and hypopnea times per unit time is displayed on the display 34 together with the determination result of the presence / absence of bed, the result of determination of the sleeping form, and the respiration curve determined in the respiration analysis flow. FIG. 12 shows an example of the display. In the display example of FIG. 12, the breathing curve is omitted. As shown in FIG. 12, the number of apnea and hypopnea per unit time when the patient is asleep with time is displayed. It is possible to grasp the number of breathing and hypopnea. It is also possible to calculate and display the sum of the number of apnea and hypopnea for each sleeping form and the average number of apnea and hypopnea per unit time.
[0069]
In the apnea analysis flow described above, in addition to judging the apnea state or the hypopnea state from the change in the amplitude of the respiration curve (step S64), based on the change in the amplitude and the cycle (frequency) of the respiration curve. Thus, an apnea state or a hypopnea state was determined (step S65).
[0070]
Here, it is difficult to strictly distinguish between the apnea state and the hypopnea state, but in general, the apnea state is more aggressive than the hypopnea state. There is a tendency for a recovery respiratory operation performed later for respiratory recovery to be strong. Therefore, the main purpose of step S64 is to determine that an apnea condition has occurred and that a strong recovery breathing operation has been performed after the apnea condition.
[0071]
However, in the case of the hypopnea state, since the subsequent recovery breathing operation may be relatively small, it may not be possible to determine the hypopnea state with high accuracy by relying only on the change in the amplitude of the respiration curve. . Therefore, the present inventor has noticed that the respiration rate of the recovery respiration operation performed after the apnea state and the hypopnea state is clearly higher than the normal respiration rate.
[0072]
FIG. 10 is a waveform diagram showing a state of a respiratory curve when a hypopnea state occurs and a recovery breathing operation is performed thereafter. As shown in FIG. 10, in the hypopnea state, the amplitude of the respiration curve decreases and the frequency also decreases. Then, during the recovery breathing operation after the hypopnea state, the amplitude increases and the frequency also increases.
[0073]
Therefore, the occurrence of the hypopnea state can be determined with high accuracy by taking into account the change in the frequency (cycle) of the respiratory curve in addition to the change in the amplitude of the respiratory curve. The main purpose of step S65 is to determine that a hypopnea condition has occurred and that a relatively small recovery breathing operation has been performed after the hypopnea condition.
[0074]
In the apnea analysis flow described above, the step of determining the apnea / hyporenea state from the change in the amplitude of the respiratory curve (step S64), and the step of determining the apnea based on the change in the amplitude and cycle (frequency) of the respiratory curve. Although the step of determining the respiratory / hyporespiratory state (step S65) is provided, step S64 may be omitted. This is because both apnea and hypopnea can be determined in step S65. Furthermore, the apnea / hypopnea state may be determined based only on the change in the cycle (frequency).
[0075]
Further, in the apnea analysis flow described above, in order to determine the difference between the maximum value and the minimum value obtained from the amplitude average of the three wavelengths of the respiration curve, the coefficient multiplied by the minimum value is 2.7 in step S64 and step In S65, a value of 2.0 was used. However, when the apnea and hypopnea states were determined using a value of 1.4 or more as this coefficient, blood oxygen saturation, mouth / nose airflow, chest movement, abdominal movement, etc. were detected. The result that the correlation with the determination result by the definitive diagnosis device that determines the apnea / hypopnea state is 0.9 or more is given. Therefore, the coefficient may be 1.4 or more.
[0076]
In the apnea analysis flow described above, the amplitudes of the three wavelengths of the respiration curve were averaged to calculate an average amplitude. By calculating the average of the amplitudes of a plurality of wavelengths in this manner, for example, as in the case of periodic limb movements, it acts on the respiratory signal as a single noise component, even when the amplitude of the respiratory signal increases, Since the noise component can be attenuated, when the apnea state or the like is determined based on the change in the amplitude of the respiration signal, the determination accuracy can be improved. The number of wavelengths whose amplitudes are averaged is not limited to the above-described three wavelengths, and the amplitudes of two wavelengths or four or more wavelengths may be averaged. Further, it is needless to say that the amplitude can be used as a local maximum without averaging the amplitude of each wavelength.
[0077]
Also, when a change in the cycle (frequency) of the respiration curve is obtained, erroneous determination due to noise can be suppressed by averaging the cycles (frequency) of a plurality of wavelengths as described above.
[0078]
In addition, in order to further improve the determination accuracy, a change in the amplitude of the respiratory signal when a local maximum occurs was monitored, and as shown in FIG. 11, the change in the amplitude converged within a predetermined time. In this case, it may be determined that the noise is not caused by the recovery respiratory operation for the recovery of the respiration but is caused by other factors. This is because the recovery breathing operation after the occurrence of the apnea state or the hypopnea state is one in which strong and fast breathing continues a plurality of times.
[0079]
Furthermore, during a predetermined period before the minimum value, the change tendency of the amplitude of the respiratory signal is monitored, and if the amplitude of the respiratory signal does not decrease, such as a monotonous increase in amplitude, it is not determined to be apnea or hypopnea. Is preferred. Thereby, the determination system of the apnea / hypopnea state can be further improved.
[0080]
In the above-described embodiment, the display 34 displays the respiratory curve and the number of times of apnea and hypopnea per unit time with the passage of time. However, other information may be displayed together on the display 34, or the result may be recorded on a predetermined storage medium or printed.
[0081]
The information to be additionally displayed includes a period of body movement such as turning over on a respiratory curve, and sleep information such as a respiratory rate during sleep and a sleep time.
[0082]
Further, as shown in FIG. 13, the relationship between the phases of the sensor signals of the pressure-sensitive elements for detecting a change in the load on the chest and the abdomen tends to be opposite in the apnea state and in phase in the hypopnea state. Therefore, when the apnea state or the hypopnea state is determined, it is determined whether the state is the apnea state or the hypopnea state from the phase relationship between the sensor signals of the chest and the abdomen, and these are classified and stored and displayed. You may.
[0083]
Further, in the above-described embodiment, the change of the cycle (frequency) of the respiratory curve from a low frequency to a high frequency is one requirement for the determination of the apnea state or the hypopnea state. The change from the high frequency to the low frequency may be detected to determine the apnea state or the hypopnea state. In this case, a state in which the respiratory recovery operation is performed after the occurrence of the apnea state or the hypopnea state, and thereafter, the state returns to the normal respiratory operation is detected.
[Brief description of the drawings]
FIG. 1 is a diagram showing an installation state when using an apnea syndrome testing apparatus A as an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of an inspection apparatus A.
FIG. 3 is a block diagram showing a circuit configuration of a control unit in the inspection device A shown in FIG.
FIG. 4 is a flowchart showing a respiration analysis flow.
FIG. 5 is a flowchart illustrating a body motion determination flow.
FIG. 6 is a flowchart illustrating a flow determination process.
FIG. 7 is a flowchart illustrating a sleeping shape determination flow.
FIG. 8 is a flowchart showing an apnea analysis flow.
FIG. 9 is a waveform chart showing an example of setting of a maximum value and a minimum value.
FIG. 10 is a waveform diagram showing a state of a respiratory curve when a hypopnea state occurs and a recovery breathing operation is performed thereafter.
FIG. 11 is a waveform diagram showing a case where the change in the amplitude of the respiration curve converges within a predetermined time.
FIG. 12 is a diagram showing an example of a display on a display unit 34.
FIG. 13 is a waveform diagram showing that the phase relationship between sensor signals of a pressure-sensitive element that detects a change in load on the chest and abdomen tends to be opposite in an apnea state and in phase in a hypopnea state. is there
[Explanation of symbols]
A… Apnea syndrome testing device A
2 ... Seat part
3. Control unit
22 ... Sensor sheet
221: Pressure sensitive element
34 ... Display

Claims (18)

Respiratory signal generating means for generating, as a respiratory signal, a load change applied to the bedding according to a body motion due to a respiration of a sleeping person,
An apnea syndrome testing apparatus, comprising: a determination unit configured to determine an apnea state or a hypopnea state of the sleeping person based on a change in the frequency of the breathing signal. The determination means also monitors the change in the amplitude of the respiratory signal, the amplitude of the respiratory signal decreases, then the amplitude of the respiratory signal increases, and the amplitude of the respiratory signal when the amplitude decreases With respect to the frequency, when the frequency of the respiratory signal when the amplitude increases increases, the state of reduced amplitude of the respiratory signal is determined to be the apnea state or the hypopnea state of the sleeping person. The inspection device for apnea syndrome according to claim 1. The test for apnea syndrome according to claim 2, wherein the determining means calculates an average value of a plurality of amplitudes in the respiratory signal, and determines a change in the amplitude of the respiratory signal from a difference between the average values. apparatus. 3. The method according to claim 2, wherein the determining unit determines that the amplitude of the respiratory signal has changed from a reduced state to an increased state when the change ratio of the amplitude of the respiratory signal is 1.4 or more. Item 4. An inspection device for apnea syndrome according to Item 3. The method according to claim 1, wherein the determining unit determines that the frequency of the respiratory signal has changed from a low frequency to a high frequency when the cycle of the respiratory signal is reduced by 0.5 s or more. An examination device for apnea syndrome according to the above. 3. The method according to claim 2, wherein the determining unit does not determine the apnea state or the hypopnea state when the period during which the amplitude of the respiratory signal increases and the frequency increases is shorter than a predetermined period. An apnea syndrome testing apparatus according to any one of claims 1 to 5. The apnea syndrome according to any one of claims 1 to 6, wherein the determining unit includes a calculating unit that calculates the number of times the sleeping person has determined that the sleeping person is in an apnea state or a hypopnea state. Inspection equipment. 4. The apparatus according to claim 1, further comprising a determination unit configured to determine an apnea state and a hypopnea state based on a phase relationship of a load change in the chest and abdomen of the sleeping person in accordance with body movements caused by respiration. A test apparatus for apnea syndrome according to claim 7. The discriminating means discriminates a hypopnea state when a phase of a load change according to body movement due to respiration is substantially the same in the chest and abdomen of the sleeping person, and determines an apnea state when the phases are substantially opposite phases. The test apparatus for apnea syndrome according to claim 8, wherein the apparatus is determined as: 10. The sleeping device according to any one of claims 1 to 9, further comprising a sleeping shape determination unit configured to determine a sleeping shape of the sleeping person when sleeping based on a load distribution on the bedding of the sleeping person. Inspection device for respiratory syndrome. The apnea syndrome testing apparatus according to claim 10, wherein the calculating means calculates the number of times of apnea or hypopnea for each of the sleeping forms determined by the sleeping form determining means. The said breathing signal generation means stops generation | occurrence | production of the said breathing signal, while the load distribution in the said bedclothes of the sleeping person is changing, The Claims 1 thru | or 11 characterized by the above-mentioned. Inspection device for apnea syndrome. Based on the state of the load applied to the bedding, comprises a bed separation determining means for determining the bed separation of the sleeping person,
The apnea syndrome according to any one of claims 1 to 12, wherein the respiratory signal generating unit stops generating the respiratory signal when it is determined that the patient is out of bed by the on / off determining unit. Inspection equipment. 14. The apnea syndrome testing apparatus according to claim 13, wherein the presence / absence-of-bed determination means determines that the user has left the bed when no load is applied to a predetermined area or more of the bedding. The apnea syndrome testing apparatus according to claim 13, wherein the presence / absence-of-bed determination unit determines that the user has left the bed when a load change according to body movement due to the respiration of the sleeping person has not occurred. The storage device according to any one of claims 7 to 14, further comprising a storage unit configured to store at least one of a respiration signal from the respiration signal generation unit, a determination result by the determination unit, and a calculation result by the calculation unit. Apnea syndrome testing device. 17. The storage unit according to claim 16, wherein the storage unit further stores a determination result by the determination unit, a determination result of the sleeping state by the sleeping state determination unit, and a determination result of the presence or absence of the bed by the presence / absence determination unit. Apnea syndrome testing device. 18. The apparatus for testing apnea syndrome according to claim 16, further comprising a notifying unit for notifying information stored in the storage unit.

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