JP2010119822A - Biological information detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biological information detector, obtaining breath, heart sound and posture information signals of a patient from detection signals of an acceleration sensor. <P>SOLUTION: This biological information detector includes: the acceleration sensor applied to the chest of a patient; a first signal processing means for detecting patient's breath and heart sound information from a dynamic acceleration signal in the Y-axis direction of the patient obtained from the acceleration sensor when the lateral direction of the patient is X-axis and the longitudinal direction thereof is Y-axis; a second signal processing means for detecting the posture information of the patient from a static acceleration signal in the X-axis direction and a dynamic acceleration signal in the Y-axis direction of the patient obtained from the acceleration sensor; and a display means for displaying breath, heart sound, posture and behavior information obtained from the first, second and third signal processing means. The posture and behavior information as well as the breath and heart sound information are detected from the X-axis and Y-axis signals. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a biological information detection apparatus for detecting a patient's breathing, heart sounds, and posture.

2. Description of the Related Art Conventionally, an apparatus for acquiring biological information such as a heartbeat and respiration of a patient by attaching an acceleration sensor to a part of a patient (including a disabled person such as an elderly person) has been known. For example, Japanese Patent Application Laid-Open No. 2002-17693 discloses a portable radio telephone type vital checker that automatically contacts a third party to prevent a serious accident when an abnormality is detected in the biological information such as heartbeat and respiration of a human body. It is described that an acceleration sensor can be used as an element for detecting heartbeat and respiration.

Further, as a device used for sleep tests and sleep apnea syndrome diagnosis, for example, a configuration disclosed in Japanese Patent No. 3809847 is known. This publication uses a three-dimensional acceleration sensor to output biological information signals in the X, Y, and Z directions, detects a patient's sleeping posture from DC components in the X and Z directions, and ACs in the X, Y, and Z directions. It is described that the component is extracted, the respiratory rate is detected from the AC component, and the heart rate is detected from the AC component in the Z direction.

JP 2002-17693 A Japanese Patent No. 3809847

Patent Document 1 discloses that an acceleration sensor is used as an element for detecting a heartbeat and respiration of a human body, but there is no specific technique for accurately measuring a heartbeat and a respiration rate from the detection signal. Not explained.

In the configuration disclosed in Patent Literature 2, three types of signals X, Y, and Z from a three-axis acceleration sensor are used to detect a change in sleeping posture, a heart rate, and a respiratory rate by combining them. There is a problem that the processing becomes complicated. Further, although the configuration disclosed in this document can obtain RR interval information from a heartbeat signal, there is a problem that heart noise cannot be detected.

An object of the present invention is to obtain patient respiration, heart sound, posture, and behavior information from two types of signals in the X and Y directions among the output signals of the acceleration sensor. It is another object of the present invention to provide a biological information detection apparatus that can also be used.

The biological information detection apparatus according to the present invention includes an acceleration sensor mounted on a patient's chest, and the patient's Y-axis obtained from the acceleration sensor when the patient's left-right direction is the X-axis and the front-rear direction is the Y-axis. First signal processing means for detecting respiratory and heart sound information of the patient from dynamic acceleration signals in the direction, static acceleration signals in the X-axis direction and static acceleration signals in the Y-axis direction obtained from the acceleration sensor Second patient signal processing means for detecting posture information of the patient from the above, and the patient behavior information from the dynamic acceleration signal in the X-axis direction and the dynamic acceleration signal in the Y-axis direction obtained from the acceleration sensor And a display means for displaying respiration, heart sound, posture and action information obtained from the first, second and third signal processing means.

In the biological information detecting apparatus according to the present invention, the first signal processing means includes a first bandpass filter that extracts a respiration frequency component from the acceleration sensor signal, and a first bandpass filter that extracts a heart sound frequency component from the acceleration sensor signal. A low-pass filter, wherein the second signal processing means extracts a frequency component related to the posture of the patient's body, such as the tilt of the patient's body, from the X-axis direction and Y-axis direction static acceleration signals from the acceleration sensor. A high-pass filter that extracts a frequency component related to behavior such as movement of the patient's body from the dynamic acceleration signals in the X-axis direction and the Y-axis direction from the acceleration sensor. Is included.

In such a configuration, only the respiratory information signal is extracted from the first bandpass filter, and only the heart sound information signal is extracted from the second bandpass filter. Thereby, a respiration information signal and a heart sound information signal can be obtained with high accuracy.

In the biological information detecting apparatus according to the present invention, the first bandpass filter has a pass frequency band from a low cut-off frequency of 0.01 to 0.1 Hz to a high cut-off frequency of 0.3 to 3 Hz. The two-band pass filter has a pass frequency band from a low cut-off frequency of 10 to 50 Hz to a high cut-off frequency of 100 to 1000 Hz, and the low-pass filter receives the X-axis and Y-axis signals from the acceleration sensor 1 and inputs 0.5 Hz or less. And the high-pass filter allows a frequency signal of 1 Hz or more to pass through.

In such a configuration, only the signal corresponding to respiration is output from the first band pass filter, the heart sound signal corresponding to the R wave and T wave in the electrocardiogram waveform is output from the second band pass filter, and the body sound is output from the low pass filter. Only a signal related to posture such as tilt is output, and only a signal related to behavior such as body movement is output from the high-pass filter. Two types of heart sound signals and heart noise corresponding to the closure of the atrioventricular valve and the arterial valve from the second band pass filter can be detected.

According to the present invention, it is possible to obtain information related to posture changes such as breathing, heart sounds, and patient body movement from two types of signals in the X and Y directions of the acceleration sensor. Therefore, it is possible to obtain the same information as in the case of using a triaxial acceleration sensor with a biaxial acceleration sensor, and since the types of signals are smaller than those of the triaxial acceleration sensor, the processing can be easily performed. There is.

According to the present invention, a signal corresponding to a T wave signal can be obtained as heart sound information in addition to an electrocardiogram waveform R wave signal. That is, two types of heart sound signals and heart noise corresponding to the closure of the atrioventricular valve and the arterial valve can be known, and thereby the heart abnormality can be found.

It is a block diagram which shows the structure of the biometric information detection apparatus which concerns on embodiment of this invention. It is a perspective view which shows the state which fixed the sensor part to the band. It is a front view which shows the state which mounted | wore the patient with the biometric information detection apparatus which concerns on this invention. It is a figure which shows the relationship between a test subject's (patient) body inclination angle, and attitude | position. It is a figure which shows the relationship between the amount of body movement of a test subject (patient), and an action state. It is a wave form diagram which shows a respiration measurement signal. It is a wave form diagram which shows a heart sound chart measurement signal.

In FIG. 1, reference numeral 1 denotes a biaxial acceleration sensor, which is attached to a portion of a patient's chest close to the heart. The acceleration sensor 1 detects changes in acceleration in two orthogonal directions (X and Y). In the present embodiment, the left-right direction of the patient is the X-axis, and the front-rear direction (the body thickness direction). ) Is the Y axis. Note that a triaxial acceleration sensor can be used instead of the biaxial acceleration sensor, and in this case, the two kinds of signals are used.

Reference numeral 2 denotes a first band-pass filter that receives the Y-axis signal from the acceleration sensor 1 and has a pass frequency band of 0.1 Hz to 0.7 Hz, and functions to extract a respiration frequency component. 3 is a second band-pass filter that similarly receives the Y-axis signal from the acceleration sensor 1 and has a pass frequency band of 50 Hz to 100 Hz, and acts to extract the frequency component of the heart sound. The Y-axis signal passes through the first and second bandpass filters 2 and 3 to obtain a dynamic acceleration signal related to respiration and a dynamic acceleration signal related to heart sound.

Reference numerals 4 and 5 denote amplifiers with a gain of 40 db for inputting the output signals of the first and second bandpass filters 2 and 3, respectively. These first and second band pass filters 2 and 3 and amplifiers 4 and 5 constitute a first signal processing means 6.

7 is a low-pass filter that receives the Y-axis signal from the acceleration sensor 1 and 8 is a low-pass filter that receives the X-axis signal from the acceleration sensor 1 and passes a frequency signal of 0.5 Hz or less. , 8 can be used to measure the body inclination angle using the two types of static acceleration signals in the X-axis direction and Y-axis direction, and change in posture can be detected. These two low-pass filters 7 and 8 constitute the second signal processing means 9.

Reference numeral 10 denotes a high-pass filter that receives the Y-axis signal from the acceleration sensor 1, and 11 denotes a high-pass filter that receives the X-axis signal from the acceleration sensor 1 and passes a frequency signal of 1 Hz or more. The amount of body movement can be measured by two types of dynamic acceleration signals in the X-axis direction and Y-axis direction obtained from the above, and the behavior can be detected. These two high-pass filters 10 and 11 constitute a third signal processing means 12.

The microcontroller 13 is a microcontroller that receives the output signals AD1, AD2, AD3, AD4, AD5, and AD6 from the amplifiers 4 and 5, the low-pass filters 7 and 8, and the high-pass filters 10 and 11, includes an AD converter, and includes a sampling frequency. Convert to digital signal at 200 Hz. The signal transmission unit 14 is a signal transmission unit that transmits six types of signals AD1, AD2, AD3, AD4, AD5, and AD6 from the microcontroller 13, and can be configured to have an antenna portion and transmit signals alone. . This signal can also be transmitted via a mobile phone, PHS or the like. A signal processing unit 15 is a signal processing unit that receives a signal from a signal transmission unit such as a cellular phone, performs arithmetic processing, and displays respiration, heart sounds, posture, and action information on a display unit such as a monitor, and includes a microcomputer. Further, the signal processing unit 15 can be incorporated in the sensor unit 16.

In FIG. 2, reference numeral 16 denotes a sensor unit in which the acceleration sensor 1, the first, second, and third signal processing units 6, 9, and 12, the microcontroller 13, and the signal transmission unit 15 are integrated. The size can be about 1 cm and the weight can be about 20 g. Reference numeral 17 denotes a band in which the sensor unit 16 is fixed at an intermediate position, and planar fasteners 18 are formed at both ends.

As shown in FIG. 3, the band 17 is wound around the chest of a subject (patient) 19 in a state of being inside the sensor unit 16 and is attached. At this time, the sensor unit 16 is disposed so as to be positioned on the heart. The sensor unit 16 may be mounted from above clothing such as underwear, and it is sufficient that there is no gap between the sensor unit 16 and the body of the subject (patient) 19. With this configuration, the burden on the patient can be reduced.

FIG. 4 shows the results of measuring the patient's body tilt angle and posture every 5 seconds from the signals AD3 and AD4 output from the low-pass filters 7 and 8, and the measured values are shown in small circles. “Front” is the front of the patient and “back” is the back. From the figure, it can be seen that the prone position, the left and right lateral position, the supine position, the sitting position and the standing position are accurately detected.

FIG. 5 shows the results of measuring the amount of body movement of the patient every 5 seconds from the signals AD5 and AD6 output from the high-pass filters 10 and 11. From the figure, the behavioral state of walking and running can be accurately detected at rest.

FIG. 6 shows the result of measuring respiration with the sensor unit 16 attached to the chest of a 22-year-old male subject 19 (FIG. 3) sitting in a chair. A waveform A shows a respiration waveform based on the signal AD1 obtained through the first bandpass filter 2 and the amplifier 4, and a waveform B is a chest that is known as a method capable of accurately detecting a respiration waveform as a comparative example. The result of applying a piezoelectric film to the same subject 19 and measuring it simultaneously is shown. The waveform signal A obtained by the present invention has a difference in period as compared with the comparison signal B, but the peak interval and frequency are the same, and it can be seen that accurate respiration detection is performed.

FIG. 7 shows the results of measuring the heart sound waveform in the same subject 19. A waveform A shows a waveform based on the signal AD2 obtained through the second bandpass filter 3 and the amplifier 5, and a waveform B shows an electrocardiogram waveform measured simultaneously as a comparative example. The R wave showing the largest peak in the electrocardiogram waveform corresponds to the sound signal emitted when the atrioventricular valve of the heart closes, and the subsequent T wave corresponds to the sound signal emitted when the heart arterial valve closes. Correspond. The waveform signal obtained by the present invention outputs two kinds of signals corresponding to these R wave and T wave. Therefore, in addition to the measurement of heart rate and RR interval, two types of heart sound signals and heart noise corresponding to the closure of the atrioventricular valve and the arterial valve can be known, thereby making it possible to detect heart abnormalities. .

When the biological information detection apparatus according to the present invention is applied to an inpatient in a hospital, the nursing center can grasp whether the patient is normal, abnormal, sleeping or whether he / she is awake. It is also useful for nursing elderly people who continue home medical care in remote areas by transmitting signals using mobile phones.

DESCRIPTION OF SYMBOLS 1 Acceleration sensor 2 1st band pass filter 3 2nd band pass filter 4, 5 Amplifier 6 1st signal processing means 7, 8 Low pass filter 9 2nd signal processing means 10, 11 High pass filter 12 3rd signal processing means 13 Microcontroller 14 Signal transmission unit 15 Signal processing unit 16 Sensor unit 17 Band 18 Fastener unit 19 Subject (patient)

Claims (4)

An acceleration sensor mounted on the patient's chest and the patient's left-right direction as the X-axis and the front-rear direction as the Y-axis, the patient's Y-axis dynamic acceleration signal obtained from the acceleration sensor The patient's posture information is detected from first signal processing means for detecting respiration and heart sound information, and the patient's X-axis direction static acceleration signal and Y-axis direction static acceleration signal obtained from the acceleration sensor. Second signal processing means; third signal processing means for detecting behavior information of the patient from a dynamic acceleration signal in the X-axis direction and a dynamic acceleration signal in the Y-axis direction obtained from the acceleration sensor; And a display means for displaying respiration, heart sound, posture, and action information obtained from the first, second and third signal processing means. The first signal processing means includes a first bandpass filter that extracts a respiration frequency component from the acceleration sensor signal, and a second bandpass filter that extracts a heart sound frequency component from the acceleration sensor signal. The processing means includes a low-pass filter that extracts a frequency component related to posture such as tilt of the patient's body from the static acceleration signals in the X-axis direction and the Y-axis direction from the acceleration sensor, and the third signal processing means 2. A living body according to claim 1, further comprising: a high-pass filter that extracts a frequency component related to an action such as movement of the patient's body from dynamic acceleration signals in the X-axis direction and the Y-axis direction from the acceleration sensor. Information detection device. The first band pass filter has a low frequency cutoff frequency of 0.01 to 0.1 Hz to a high frequency cutoff frequency of 0.3 to 3 Hz, and the second band pass filter has a low frequency cutoff frequency of 10 to 50 Hz. The low-pass filter is a filter that passes the X-axis and Y-axis signals from the acceleration sensor 1 and allows a frequency signal of 0.5 Hz or less to pass through. The biological information detecting device according to claim 2. The living body information detecting apparatus according to claim 1, wherein the acceleration sensor is a biaxial or triaxial acceleration sensor.

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