JPH0595914A - Biological information processing device and its monitoring device - Google Patents

Abstract

(57) [Summary] [Purpose] This is related to the safety management of inpatients in hospitals and residents in nursing homes. By sharing the information transmission route, it is possible to easily respond even if the number of patients to be monitored increases. It can be so. [Constitution] The monitor device comprises an interface device 22 for connecting the communication cable 21 to the biological information processing devices 20a to 20d for detecting the body movement, respiration, heartbeat, etc. of a patient in a non-contact manner, and an interface device 22 for the communication cable 21. It is composed of a computer equipped with a display unit that is connected via the display unit to monitor information from the biological information processing devices 20a to 20d.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biological information processing apparatus for obtaining the presence / absence of a patient's bed, the time of falling asleep, the breathing / heart rate from the information such as the body movement of the patient, and the inpatient of a hospital or a nursing home. The present invention relates to a monitor device that intensively monitors residents from the viewpoint of nursing.

[0002]

2. Description of the Related Art Conventionally, in-bed management of inpatients and the like has been performed by patrols by nurses or monitors by a television camera. As a technique for automating this, for example, as disclosed in Japanese Patent Laid-Open No. 14928/1990, a method of monitoring the state of a sleeping person by pairing the sleeping person with a display device has been devised. FIG. 12 shows the configuration of the device. Detection unit 26 for detecting body movements of the sleeping person
And the display unit 27 are connected as a pair by a cable 28. In addition, as a technique for intensively monitoring a plurality of patients in a bed management using a piezoelectric element or the like, Japanese Patent Application No.
As disclosed in Japanese Patent No. 1618222, a device has been devised in which the detection unit and the circuit unit are connected to one display device according to the number of patients. FIG. 13 shows the configuration of the device. In the figure, in the circuit unit 29, the coarse body movements of the patient and the fine body movements such as heartbeats and respirations are determined by comparison with a threshold value, and the presence / absence state and the sleep state of the patient are displayed via the communication unit 30. 31 is monitoring. It should be noted that the detection of the sleep state is based on the time when the resting time of the coarse body movement exceeds 15 minutes.

Regarding the counting of the heart rate, a method in which an electrode or the like is attached to the patient's body has been adopted in the case where a direct measurement by a doctor or a nurse is generally performed automatically.

[0004]

However, in the above-mentioned conventional method, the means of patrol by the nurses imposes a great burden on the nurses. Has been taken up as. In addition, there is also a problem in that if a situation such as a sudden change in the patient's condition occurs between patrols, the discovery will be delayed.

Further, in monitoring by a television camera, it is expected that the patient will always be aware that he / she is being monitored, which may cause stress to the patient.

On the other hand, in the method of constructing the detection device and the display device in pairs, when the number of patients increases in a large-scale hospital or the like, the display device must be installed each time, and intensive monitoring of a plurality of patients is performed. Will cause inconvenience.

Even when a plurality of patients can be monitored at one time, there are individual differences in the level when the coarse body movements, heartbeats, and respirations of individual patients are converted into electrical signals. It is problematic to apply the threshold for motion discrimination uniformly to all patients. However, even in the same individual, it is difficult to respond with a certain threshold value throughout the night because the level of fine movement decreases as the sleep gets deeper.

Although attaching electrodes to a patient for counting heart rate and the like greatly impairs the patient's freedom, biological information from a non-contact sensor such as a piezoelectric element contains various noises. However, it is not possible to obtain an accurate value for counting the heart rate or the like by simply counting the maximum points of the waveform as in the case where the electrodes are directly attached.

Further, when a cable is pulled independently from the location of each patient to the location of the display device, the wiring must be increased as the number of patients increases.

The present invention solves the above problems. A first object of the present invention is to reduce the stress on a patient by taking in the biological information of the patient in a non-contact manner without making the patient aware of the stress, and the information is stored in real time. It is to be able to deal with sudden changes in condition by analyzing in.

A second object is to set a threshold value according to the signal level of each patient in consideration of the variation of the signal level of the biometric information between individuals and within an individual, even when monitoring a plurality of patients. It is to be able to make an accurate determination.

A third object is to calculate an accurate heartbeat / respiration rate from a signal output from a non-contact sensor such as a piezoelectric element containing a lot of noise.

A fourth object is to make it possible to easily cope with an increase in the number of patients to be monitored by sharing the information transmission path.

[0014]

In order to solve the above-mentioned problems, a biological information processing apparatus of the present invention comprises a biological information acquisition apparatus for detecting body movements, respirations, heartbeats, etc. of a patient in a non-contact manner and converting them into electric signals. An A / D conversion circuit for converting a signal from the biological information acquisition device into a digital value, and determination of whether the patient is in bed or out of bed based on the digital value converted by the A / D conversion circuit,
It has an arithmetic circuit for judging falling asleep and calculating the respiratory rate and heart rate, and the arithmetic circuit stores the digital value in a plurality of storage means, and the body movements such as respiration and heartbeat of the patient and turning over. Threshold value determining means for determining a threshold value for discriminating coarse body movements according to the level of the digital value, and determination for determining whether the patient is asleep or falling asleep using the digital value and the threshold value stored in the storage means And means for calculating the respiration rate / heart rate of the patient per unit time.

The threshold value determining means in the biometric information processing apparatus of the present invention is a first maximum point searching means for obtaining a plurality of maximum points at which the differential value of the digital value changes from positive to negative as a first maximum point set. And the maximum value of the first maximum point set does not exceed the threshold value by a certain amount or more, the difference between the maximum value and the minimum value is equal to or less than a preset voltage, and the interval between the elements of the first maximum point set is Judging means for judging that the difference between the maximum value and the minimum value is within a preset time and outputting a judgment signal; and a constant for the maximum value of the first maximum point set upon receiving the output from the judgment signal. And an updating unit that determines a value obtained by adding the offset voltage of 1 to the threshold value.

Further, the calculating means in the biological information processing apparatus of the present invention relates to the autocorrelation coefficient calculating means for calculating the autocorrelation coefficient from the series of digital values stored in the storage means, and the autocorrelation coefficient. Second maximum point searching means, which is a second maximum point set, having a plurality of maximum points having a differential value changing from positive to negative and larger than a value of a function having a lag as a variable; and the second maximum point. It is assumed that the first lag indicated by the element having the maximum value of the set is a time obtained by multiplying the basic cycle of the heartbeat or respiration of the patient by an integer, and the first local lag is divided into an integer, and the second maximum is near the second lag. A basic cycle calculation means that searches whether or not an element of a point set exists and, if the search is successful, uses the second lag indicated by the searched element as a basic cycle and, if it fails, uses the first lag as a basic cycle From the basic cycle, per unit time It is obtained by a calculating means for calculating a respiratory rate, heart rate.

Further, the monitor device of the present invention comprises a plurality of biological information processing devices, a communication cable, a plurality of interface devices for connecting the biological information processing device and the communication cable, the communication cable and the interface device. And a computer that is connected via a display means for monitoring information from the biological information processing apparatus.

[0018]

With the above structure, in the biological information processing apparatus of the present invention, the biological information acquisition apparatus 1 detects the body movement, respiration, heartbeat, etc. of the patient in a non-contact manner and outputs it as an electric signal, and then by the A / D conversion circuit. The signal is converted into a digital value, and the arithmetic circuit calculates the presence / absence of bed of the patient, detection of sleep, and calculation of heart rate / respiration rate.

In the threshold value determining means in the arithmetic circuit of the biological information processing apparatus of the present invention, the first maximal point set is obtained from the stored digital data by the first maximal point searching means, and the judging means is the first. Whether or not the threshold value is updated is determined based on the maximum point set and the threshold value. When updating, the updating means updates the threshold value.

Further, the calculating means in the arithmetic circuit of the biological information processing apparatus of the present invention calculates the autocorrelation coefficient from the stored digital value by the autocorrelation coefficient calculating means, and the second maximum point searching means operates. Find the second set of maximum points. From the obtained second set of maximum points, the basic period calculation means obtains the basic period, and the calculation means calculates the heart rate or respiration rate per unit time.

Further, the monitor device of the present invention uses the signal processing device to determine whether the patient is in bed / absent bed, sleep / wake, and calculate heart rate, respiration rate, etc. Better display on computer via communication cable.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram for explaining the first embodiment of the present invention. In the figure, reference numeral 1 denotes a biometric information acquisition device, which is composed of a piezoelectric element 2 such as polyvinylidene fluoride, a filter circuit 3, an amplification circuit 4, a rectification circuit 5, and an integration circuit 6. The biometric information acquisition device 1 is connected with an A / D conversion circuit 7 and an arithmetic circuit 8 in this order. FIG. 2 is a block diagram of the arithmetic circuit 8. The input A / D conversion value is stored in the storage means 9, and the threshold value determining means 10 and the determining means 1
1 is sent to the calculation means 12. At the same time, the output of the threshold value determining means 10 is also input to the determining means 11 and the calculating means 12.

Next, the operation of the first embodiment will be described. The piezoelectric element 2 detects the body movement, respiration, heartbeat, etc. of the patient in a non-contact manner and outputs it as an electric signal, and the filter circuit 3 outputs necessary biological information for the input electric signal, that is, coarse body movement, respiration, heartbeat, etc. The signal in the frequency band corresponding to is extracted. As a result, frequency components irrelevant to the biological information, such as AC 50 or 60 Hz, are removed. The amplifier circuit 4 amplifies the signal extracted by the filter circuit 2 to an appropriate level. The rectifying circuit 5 rectifies the AC signal into a signal composed of only the DC component, and the integrating circuit 6 integrates the rectified signal.
Then, the A / D conversion circuit 7 converts the signal into a digital value. The sampling frequency at this time may be, for example, 20 Hz or higher if a heartbeat is detected. The converted digital value is sent to the arithmetic circuit 8 where the patient's presence / absence of bed, sleep detection, heart rate / respiration rate, etc. are calculated.

In the arithmetic circuit 8, the storage means 9 sequentially stores the A / D-converted digital values sent continuously. The number of data stored at this time depends on the sampling frequency. If the heart rate is calculated, data for at least about 5 seconds is required, so 100 data must be held when the sampling frequency is 20 Hz. When the number of stored data reaches 100, the oldest data is erased and the newly sent data is stored.

Next, the threshold value determining means 10 determines a threshold value for distinguishing between fine body movement and coarse body movement based on the stored digital value. Using the determined threshold value and the stored digital value, the determination means 11 determines whether the person is in bed or not, and detects sleep by counting the body motion rest time, and the calculation means 12 calculates the heartbeat or respiration rate. ..

Whether the person is in the bed or not is in the stored 100
This is performed by searching the data of which the value is 0. Since the signal from the piezoelectric element 1 is rectified and integrated, the value does not become 0 as a result of detecting fine body motion as long as the patient is in bed. When the luggage is placed on the bed, the value temporarily increases, but it immediately returns to the 0 level.
This distinguishes between the case where a person enters the bed and the case where an object is placed. As a condition of absence, there may be adopted a method of making it absent if there is even one piece of 0 data, and a method of judging by what percentage the number of 0 level data occupies 100 pieces of the whole data.

Regarding the detection of sleep onset, the time during which the digital value newly input is in the bed state and does not exceed the threshold value for distinguishing between the fine body movement and the coarse body movement, that is, the body movement rest time reaches 15 minutes. Judge by The time of 15 minutes was obtained by an experiment by the inventors' group.

Next, a second embodiment of the present invention will be described. FIG. 3 is a block diagram of the second embodiment of the present invention.
In the figure, the first maximum point searching means 13 is connected so as to send the first maximum point set to the judging means 14. The current threshold value (the initial value is 10 v in the second embodiment) is also given as an input to the determination means 14. The output of the judging means 14 is connected to the input of the updating means 15.

Next, the operation of the second embodiment will be described. FIG. 4 is a flow chart of signal processing in the threshold value determining means 10. The number of data currently stored in the storage means 9 is N
Then, each data is represented as data (i) (0 ≦ i ≦ N). Also, let P be the number of elements in the first maximum point set.
Then, each element is represented as peak (j) (0 ≦ j ≦ P).

After initializing the control variables x and y, data
Check whether (x) is the maximum point. Whether or not it is the maximum point may be determined by checking whether or not the differential value data ′ (x) of data (x) changes from positive to negative. If it is a maximum point, x is substituted into peak (y) to search for the next maximum point.

If P maximum points are found, then peak (j)
The maximum value pmax of the value data (peak (j)) corresponding to each of If the difference between pmax and the current threshold value is a constant V1 or more, the threshold value is not changed. When it is less than V1, the minimum value pmin of data (peak (j)) is obtained. If the difference between pmax and pmin is a constant V2 or more, the threshold value is not changed. When it is less than V2, the average interval pint of each maximum point is calculated by the following equation.

[0033]

[Equation 1]

The difference between pint and each interval is compared with a constant V3. If there is at least one difference of V3 or more, the threshold value is not changed. When all differences are less than V3, the threshold is updated to pmax plus the expected voltage variation. The expected fluctuation is the fluctuation of the vibration width due to the heartbeat that occurs independently of the coarse body movement. If this is not taken into consideration, it is determined that coarse body movement has occurred even if the vibration width due to the heartbeat fluctuates a little. The threshold updated as described above is
It will also be subject to the next update.

D when the coarse body motion is included in FIG.
The fluctuation of ata (i) and FIG. 5- (b) show the fluctuation of only the small body movement due to the heartbeat. In the above explanation, pmax is shown in FIG.
In (a), the value p1 is indicated, and in FIG. 5- (b), p1 and p3 are indicated. Further, pmin indicates p3 and p5 in FIG. 5- (a), and p2, p4, and p5 in FIG. 5- (b). Further, the intervals of the maximum values refer to IPI1 to IPI4 in both FIGS. At this time, the threshold value is updated only in the case of FIG.

Next, a third embodiment of the present invention will be described. FIG. 6 is a block diagram of the third embodiment of the present invention.
In the figure, the autocorrelation coefficient calculating means 16 is connected so as to output the calculation result to the second maximum point searching means 17. Second
The maximum point searching means 17 is connected to the basic cycle calculating means 18, and the basic cycle calculating means 18 is connected to the calculating means 19.

FIG. 7 is a flow chart of signal processing in the calculation means 12. When obtaining the autocorrelation coefficient, the autocorrelation function is first obtained. The autocorrelation function is a function that represents the correlation between the value at a certain time point and the value at a time point that is separated by an arbitrary time (called a lag) τ. In this embodiment, since the discrete data is obtained at the sampling rate of 20 Hz,
τ can be expressed as p · Δt. p represents the number of sampling data, and Δt represents the sampling period. The maximum value τmax of the lag must be set within a range not exceeding N · Δt. When M = N−τmax, generally, the autocorrelation function C (p) is

[0038]

[Equation 2]

It is calculated by However, in this embodiment, since the original waveform is subjected to the rectification and integration processing, the data
DC component in (i)

[0040]

[Outer 1]

Since it can be seen that the
It is better to obtain C (p) as follows.

[0042]

[Equation 3]

[0043]

[Equation 4]

The autocorrelation coefficient R (p) is obtained by the following equation. R (p) = C (p) / C (0) FIG. 9 is a graph showing the autocorrelation coefficient obtained in FIG. On the other hand, in the third embodiment, the points c, d, and e are first obtained as the elements of the second set of maximum points. Next, the cycle corresponding to the maximum value e of these is set as a temporary basic cycle. This can be an integer multiple of the true fundamental period, so
It is searched whether or not there is an element of the second maximum point set in the vicinity of the period of 1 / integer. In the third embodiment, the point c corresponds to it, so that the cycle corresponding to the point c is the basic cycle T.

When the basic period T is obtained, the heart rate per unit time can be calculated. The heart rate HR per minute is obtained by HR = 60 · sampling frequency / T 2. Of course, if the characteristics of the filter circuit 2 are changed, the respiration rate can be calculated in exactly the same manner.

FIG. 9 is a block diagram of the fourth embodiment. Figure 9
In, the biological information processing devices 20a to 20d are connected to the communication cable 21 by the interface devices 22a to 22d. A computer 23 is also connected to the communication cable 21 via an interface device 22e.

As shown in FIG. 10, the piezoelectric element 2 is arranged in a band on a bed 24 used by a patient. When the patient actually uses the bed 24, a bedding, a bed pad, a sheet, a blanket, or the like is laid on the installation surface of the piezoelectric element 2, so that the piezoelectric element 2 is not directly visible to the patient. In addition, a signal processing device 25 in which the filter circuit 3, the amplification circuit 4, the rectification circuit 5, the integration circuit 6, the A / D conversion circuit 7, and the arithmetic circuit 8 are integrated is also attached at an inconspicuous position near the installation position of the piezoelectric element 2. Has been.

In the fourth embodiment, since the pair of the piezoelectric element 2 and the signal processing device 25 is attached to the bed 24, one patient occupies the piezoelectric element 2 and the signal processing device 25. Therefore, with the configuration shown in FIG. 9, four patients can be monitored simultaneously.

Next, the operation of the fourth embodiment will be described. In the above configuration, the piezoelectric element 2 is
It detects changes in pressure due to heartbeat and respiration, and converts the changes into analog electrical signals. Biometric information processing device 2
0 indicates that the patient is in bed / absent, sleep / wake state, heartbeat /
The respiratory rate and the like are obtained and the information is output to the interface devices 22a to 22d.

The computer 23 is the interface device 2
Handshake communication is performed with the interface devices 22a to 22d via 2e. That is, the interface device 2
Each 2 has its own ID number, and when a data request command specifying an ID flows from the computer 23 onto the communication cable 21, the data related to the patient sent from the biometric information processing device 1 is changed to the specified ID. Is sent to the communication cable 21 from the interface device 22 having.
The computer 23 takes in this data via the interface device 22e and displays it on the screen as monitor information.

The information that can be monitored includes the above-mentioned presence / absence of the patient's bed, falling asleep / wakefulness, heartbeat /
Besides the respiratory rate, the waveform data itself can be communicated.
Furthermore, if the communication system is compatible with a general-purpose LAN, the room temperature, humidity, and brightness of the patient room can be monitored at the same time. Further, in the present embodiment, an example in which four patients are monitored has been described, but it goes without saying that the number of patients can be increased as long as there is a margin in the information transfer amount of the communication cable. Note that FIG.
Fig. 1 shows an example of the monitor screen.

[0052]

As described above, according to the biological information processing apparatus of the present invention and the monitor thereof, the following effects can be obtained.

1. Since the condition of all patients is monitored in real time, it is possible to quickly respond to sudden changes in the patient's condition.

2. Since the judgment thresholds of the coarse body movement / fine body movement can be constantly updated so as to cope with the change in the waveform level between the patients or within the patient, the state with the highest sensitivity can be maintained.

3. Since the heart rate and respiration rate are calculated using the autocorrelation coefficient, an accurate heart rate and respiration rate can be obtained even from a waveform containing considerable noise.

4. Since the information of a plurality of patients can be displayed on the screen of one computer, it is possible to reduce the burden of visiting a nurse.

[Brief description of drawings]

FIG. 1 is a block diagram of a biological information processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of an arithmetic circuit of the device.

FIG. 3 is a block diagram of threshold value determining means in the second embodiment of the present invention.

FIG. 4 is a flowchart of a threshold value determining unit of the device.

[Fig. 5] Graph of original waveform of the device

FIG. 6 is a block diagram of calculation means in a third embodiment of the present invention.

FIG. 7 is a flowchart of a calculation means of the device.

FIG. 8 is a graph of an autocorrelation coefficient of the device.

FIG. 9 is a configuration diagram of a monitor device according to a fourth embodiment of the present invention.

FIG. 10 is an explanatory diagram for mounting the piezoelectric element of the same device.

[Fig. 11] Output diagram of the monitor screen of the device

FIG. 12 is a block diagram of a conventional monitor device.

FIG. 13 is a block diagram of a conventional centralized monitor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Biometric information acquisition device 7 A / D conversion circuit 8 Arithmetic circuit 13 1st local maximum point search means 14 Judgment means 15 Update means 16 Autocorrelation coefficient calculation means 17 2nd local maximum point search means 18 Basic period calculation means 19 Calculation Means 21 Communication cable 22 Interface device 23 Computer

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Claims (4)

[Claims] 1. A biometric information acquisition device for non-contact detection of a patient's body movement, respiration, heartbeat, etc., and conversion into an electric signal, and an A / D conversion circuit for converting the signal from the biometric information acquisition device into a digital value. And an arithmetic circuit for judging the presence / absence of bed of the patient, the judgment of falling asleep and the calculation of the respiratory rate / heart rate from the digital value converted by the A / D conversion circuit. Storage means for storing a plurality of the digital values, threshold value determining means for determining a threshold value for discriminating thin body movements such as respiration and heartbeat of the patient and coarse body movements such as rolling over according to the level of the digital value A living body including a determination unit that determines whether the patient is asleep or falling asleep using the digital value and the threshold value stored in the storage unit, and a calculation unit that calculates the respiratory rate / heart rate of the patient per unit time Information processing device. 2. The threshold determining means includes a first maximum point searching means for obtaining a plurality of maximum points at which a differential value of a digital value changes from positive to negative as a first maximum point set, and the first maximum point. The maximum value of the set does not exceed a threshold value more than a certain value, the difference between the maximum value and the minimum value is equal to or less than a preset voltage, and the difference between the maximum value and the minimum value of the interval between the elements of the first maximum point set is set in advance. Judgment means for judging that it is within a set time and outputting a judgment signal, and a threshold value which is a value obtained by adding a constant offset voltage to the maximum value of the first maximum point set in response to the output from the judgment signal. The biometric information processing apparatus according to claim 1, further comprising an updating unit that determines that 3. The calculation means calculates an autocorrelation coefficient from a series of digital values stored in a storage means, and a value of a function having a lag as a variable for the autocorrelation coefficient. Second maximal point searching means for defining a plurality of maximal points whose differential values change from positive to negative as a second maximal point set, and an element having the maximum value of the second maximal point set It is assumed that the first lag is a time obtained by multiplying the basic cycle of the patient's heartbeat or respiration by an integer, and whether or not the element of the second maximum point set exists in the vicinity of the second lag obtained by dividing the first lag by an integer. If the search is successful, the second lag indicated by the searched element is used as the basic cycle, and if the search is unsuccessful, the basic cycle is calculated using the first lag as the basic cycle, and a unit time from the basic cycle. Equipped with a calculation means for calculating the respiratory rate and heart rate per hit Biological information processing apparatus according to claim 1. 4. A plurality of biometrics information processing devices, a communication cable, a plurality of interface devices connecting the biometrics information processing device and the communication cables, and the biometrics connected via the communication cables and the interface devices. A monitor device comprising a computer having a display means for monitoring information from the information processing device.