JP2795106B2 - Biological information processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for non-contact determination of respiration and heart rate from changes in body surface pressure caused by respiration and heart rate activities of a sleeping person.

[0002]

2. Description of the Related Art Hitherto, in-bed management of inpatients and the like has been performed by patrols by nurses or by monitors using television cameras. Techniques for automating this include:
For example, as disclosed in Japanese Patent Application Laid-Open No. 2-14928, a method of monitoring the state of a sleeping person using a sleeping person and a display device as a pair has been devised. FIG. 6 shows the configuration of the same device. Detector 1 for detecting body movements of sleeping person
2a, 12b, 12c and the display unit 13 are connected by a cable 14 as a pair.

[0003] Regarding the counting of the heart rate, a direct measurement by a doctor or a nurse is common, and when the measurement is performed automatically, a method of attaching an electrode or the like to the patient's body has been adopted.

[0004]

In the above-mentioned conventional method, the burden on nurses is extremely large in the case of patrols by nurses, and especially, night patrols are taken up as social issues due to the shortage of the absolute number of nurses. Have been. In addition, if a situation such as a sudden change in the patient's condition occurs between rounds, there is also a problem that its discovery is delayed.

Although mounting electrodes on a patient for counting a heart rate or the like greatly impairs the patient's freedom, biological information from a non-contact sensor such as a piezoelectric element contains various noises. As for counting the heart rate and the like, an accurate value cannot be obtained by simply counting the peaks of the waveform as in the case where the electrodes are directly attached.

Further, when the amount of change in pressure on the body surface due to heartbeat activity is small, such as in an elderly person, a sufficiently accurate heart rate cannot be obtained by sensing only one point.

[0007]

[0008] The present invention solves the above-mentioned problems, and the
The first purpose is to use information effective from a plurality of sensors.
An object of the present invention is to improve the calculation accuracy of the respiratory rate and the heart rate by calculating the average of the values of the sensors including information .

A second object is to add the respective values of a plurality of sensors in consideration of individual differences in the signal level of biological information and intra-individual fluctuations, thereby increasing the feature amount, and calculating the respiratory rate / heart rate. Is to increase.

[0010]

In order to solve the above-mentioned problems, a biological information processing apparatus according to the present invention comprises a plurality of sensors disposed on bedding for detecting a change in body surface pressure caused by a living activity of a sleeping person; A plurality of signal processing circuits connected to each of the sensors and for amplifying and filtering signals from the sensors; and A having the same number of input channels as the plurality of signal processing circuits and A / D converting an output of the signal processing circuits. A / D conversion circuit, a storage circuit for storing the conversion result of the A / D conversion circuit, and a command to start the conversion at a constant period to the A / D conversion circuit, and the A / D conversion result stored in the storage circuit a control circuit which performs more sleeping person in heart rate, respiration rate calculation, the control
The circuit is connected to the timer means and the timer means,
Basic cycle for calculating the basic cycle for each channel of the D conversion circuit
Period calculating means, and a basic cycle in the basic cycle calculating means.
For the channels for which the calculation was successful,
Average value calculation means for calculating the average value of the basic period between the tunnels
And the average calculated by the average calculation means.
Consists of conversion means for converting heart rate and respiratory rate per unit time
It was done.

[0011] Further, it is arranged on the bedding and the living activity of the sleeping person is improved.
A plurality of sensors for detecting pressure changes on the body surface caused by the
Connect to each of the sensors and amplify the signal from this sensor
A plurality of signal processing circuits for filtering, and the plurality of signal processings;
Circuit having the same number of input channels as the circuit,
An A / D conversion circuit for A / D converting the output;
A storage circuit for storing the conversion result of the conversion circuit;
And a storage circuit for instructing the conversion circuit to start conversion at a constant cycle.
Heart rate and respiration of a sleeping person from the A / D conversion results stored in
A control circuit for calculating the number.
A / D conversion result connected to the timer means and the timer means
Meet the condition that is below the level set for a certain period of time.
Adding means for adding the A / D conversion result for the channel
And the basic period using the addition result in the adding means.
Calculating the basic cycle calculating means, and the basic cycle calculating means
Heart rate and respiration per unit time
It is composed of conversion means for converting into numbers .

[0012]

[0013]

With the above arrangement, in the biological information processing apparatus of the present invention, the sensor electrically responds to a pressure change on the body surface caused by the living activity of the sleeping person, and the signal processing circuit amplifies and filters the output of the sensor. , The A / D conversion circuit receives the A / D conversion start signal from the control circuit, A / D converts the output from the signal processing circuit, the storage circuit stores the A / D conversion result, and the control circuit performs A / D conversion. A conversion start command is output to the D conversion circuit at a constant period, and the A / D conversion result is read from the storage circuit to calculate the heartbeat and respiration rate of the sleeping person per unit time.

The control circuit calculates the basic period for each channel by referring to the A / D conversion result stored in the storage circuit in the basic period calculating means, and calculates the basic period of the channel for which the basic period has been successfully calculated in the average value calculating means. An average value of the cycle is calculated, and the conversion means converts the average value into a heart rate / respiration rate per unit time.

Further, the control circuit refers to the A / D conversion result stored in the storage circuit in the adding means, and adds the A / D conversion result for a channel satisfying a condition that is equal to or less than a predetermined level for a certain period of time. The calculating means calculates a basic cycle for the addition result, and the converting means converts the basic cycle into a heart rate / respiratory rate per unit time.

[0016]

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

FIG. 1 is a block diagram of a first embodiment of the present invention. In this embodiment, the sensors 1a, 1b and 1c are buried in the bed pad 2 and the signal processing circuits 3a, 3b and 3c.
c and are connected to each other. The sensor 1a is located near the sleeping person's shoulder, the sensor 1b is located slightly below the scapula, and the sensor 1c is located near the hip. As the sensors 1a to 1c, for example, a piezoelectric element such as polyvinylidene fluoride processed into a thin film is used. Signal processing circuit 3
a to 3c are connected to the A / D conversion circuit 4. A /
The D conversion circuit 4 includes an A / D converter, and is configured to receive a conversion start trigger from the control circuit 5 and output a conversion result to the storage circuit 6. A microcomputer is used for the control circuit 5 and is connected to the storage circuit 6. As the storage circuit 6, a DRAM or the like is used.

In the above configuration, the sensors 1a to 1c generate a potential by a pressure change on the body surface caused by a living activity of a sleeping person. The generated potentials are applied to each of the signal processing circuits 3a to 3a.
It is amplified and filtered at 3c. At this time, the frequency of the signal passing through the filter is preferably, for example, about 0 to 10 Hz in the case of a heartbeat. Here, a smoothing process may be added in order to efficiently perform the subsequent processes. In the first embodiment, the A / D conversion circuit 4 has three channel inputs for receiving the outputs of the signal processing circuits 3a to 3c. A
Upon receiving a conversion start trigger from the control circuit 5, the / D conversion circuit 4 converts all the inputs of the three channels into digital values and sends them to the storage circuit 6. The storage circuit 6 is an A / D conversion circuit 4
The conversion results sent from the storage device are sequentially stored. The control circuit 5 triggers the A / D conversion circuit 4 to start the conversion at regular intervals, reads the A / D conversion results from the storage circuit 6 in order, and based on the read data, the heart rate and respiration of the sleeping person. Calculate the number. At this time, the frequency of the conversion start trigger is 20 to 30 Hz in the case of a heartbeat. The data to be read is the past 5 seconds in the case of a heartbeat, and the A / D conversion circuit 4 stores the data for the next 5 seconds while processing this data. Therefore, the storage circuit 6 needs a capacity to store data of three channels for a total of 10 seconds.

FIG. 2 is a block diagram of the control circuit 5 according to the first embodiment. The control circuit 5 includes a timer means 7, a basic cycle calculating means 8, an average value calculating means 9, and a converting means 10. . The timer means 7 is configured to send a conversion start trigger to the A / D conversion means 4 at a constant cycle, and to notify the basic cycle calculation means 8 of the start timing of the processing every 5 seconds.

FIG. 3 shows a control circuit 5 according to the first embodiment.
It is a flowchart of a process. A series of arithmetic processing in the control circuit 5 is started upon receiving a processing start command from the timer means 7. First, variables and arrays used internally are initialized. CH is a control variable for designating a channel, array CY [CH] is a basic period for each channel, and array FLG
[CH] is a flag indicating whether or not the basic cycle has been successfully calculated for each channel, and MEAN is an average basic cycle. After the initialization, the current channel is checked. If the channel is an unprocessed channel, a basic cycle is obtained from the A / D conversion result. In calculating the fundamental period, for example, a method using an autocorrelation function can be used. When the fundamental frequency is obtained, 1 is substituted for the value of the flag array. The channel variable CH is incremented, and the same processing is repeated for all the channels. Next, referring to the flag array, an average value of the basic periods of the channels for which the basic period has been successfully calculated is obtained. Finally, the number of cycles per unit time is obtained from the average value of the basic cycle.
This can be done by dividing (unit time) by (basic period).

The following describes a second embodiment of the present invention. FIG. 4 is a block diagram of a second embodiment of the present invention. The control circuit 5 includes a timer 7, an adder 11, a basic period calculator 8, and a converter 10. The timer means 7 is configured to send a conversion start trigger to the A / D conversion means 4 at a constant cycle, and to notify the basic cycle calculation means 8 of the start timing of the processing every 5 seconds.

FIG. 5 shows a control circuit 5 according to the second embodiment.
It is a flowchart of a process. A series of arithmetic processing in the control circuit 5 is started upon receiving a processing start command from the timer means 7. First, variables and arrays used internally are initialized. CH is a control variable for specifying a channel, D
P is a data designating variable for referring to the A / D conversion data, and SUM [DP] is an array indicating the result of adding the A / D conversion data.

After the initialization, the current channel is checked, and if the channel is an unprocessed channel, all data of the channel are compared with a threshold constant TH. If all data is less than the threshold TH, initialize DP,
The data of the channel is added to the array SUM.
When the addition is completed, or when the data of the channel contains a value equal to or greater than TH, CH is incremented, DP is initialized again, and the next channel is confirmed. When all channels have been processed,
The basic period of the added signal is calculated using the array SUM storing the addition result. The basic cycle is converted into a heart rate / respiration rate per unit time.

The reason why the addition processing is performed in the second embodiment is to further emphasize the characteristics of the signal. The original waveform of each channel contains many noise components, which hinders the calculation of the fundamental period. However, if signal addition is performed between channels,
The respiratory component is emphasized, and the basic cycle can be easily calculated. The comparison with the threshold value TH before the addition is performed, for example, when the channel has a waveform that detects a partial body motion and masks a characteristic component of heartbeat / respiration. This is to exclude from the addition channel.

In the present invention, whether the heart rate or the respiration rate is detected can be easily changed by changing the characteristics of the filter of the signal processing circuit 3.

[0026]

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

[0027]

1 . Since the average is obtained for information from a plurality of sensors, the calculation accuracy of the respiratory rate and the heart rate can be improved.

2 . By adding the values of the plurality of sensors, the feature amount of the signal can be increased, and the calculation accuracy of the respiratory rate / heart rate can be improved.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a control circuit according to the first embodiment;

FIG. 3 is a flowchart of a process in the first embodiment.

FIG. 4 is a block diagram of a control circuit according to a second embodiment of the present invention.

FIG. 5 is a flowchart of processing in a second embodiment.

FIG. 6 is a configuration diagram of a monitor device according to a conventional technique.

Claims (2)

(57) [Claims] 1. A plurality of sensors disposed on bedding for detecting a change in body surface pressure caused by a living activity of a sleeping person, and a plurality of signals connected to each of the sensors and amplifying and filtering a signal from the sensors. A processing circuit, an A / D conversion circuit having the same number of input channels as the plurality of signal processing circuits and A / D converting an output of the signal processing circuit, and a storage for storing a conversion result of the A / D conversion circuit with circuit and a control circuit for performing the a / D conversion circuit commands the start of conversion at a constant period and the calculation of the sleeping person of the heart rate, respiratory rate than has been a / D conversion result stored in the storage circuit, wherein The control circuit is a timer hand
Stage and a channel of an A / D conversion circuit connected to the timer means.
A basic cycle calculating means for calculating a basic cycle for each channel;
The basic cycle calculation means succeeds in calculating the basic cycle.
Basic channel between successful channels
Average value calculating means for calculating an average value of a period;
The average value calculated by the output means is the heart rate per unit time.
A biological information processing apparatus including a conversion unit that converts the information into a respiration rate ; 2. A plurality of sensors disposed on bedding for detecting a change in body surface pressure caused by a living activity of a sleeping person, and a plurality of signals connected to each of the sensors and amplifying and filtering signals from the sensors. A processing circuit, an A / D conversion circuit having the same number of input channels as the plurality of signal processing circuits and A / D converting an output of the signal processing circuit, and a storage for storing a conversion result of the A / D conversion circuit with circuit and a control circuit for performing the a / D conversion circuit commands the start of conversion at a constant period and the calculation of the sleeping person of the heart rate, respiratory rate than has been a / D conversion result stored in the storage circuit, wherein The control circuit is a timer hand
A / D conversion result is constant by connecting to the stage and the timer means
A channel that satisfies the condition that is equal to or less than the time fixed level
Adding means for adding the A / D conversion result of the
Calculate the basic period using the addition result in the adding means
Basic cycle calculating means, and the basic cycle calculating means.
Convert the calculated basic cycle to heart rate / respiratory rate per unit time
A biological information processing apparatus comprising a conversion means for converting .