JPS59189832A - Apparatus for measuring breathing number - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a respiration rate measuring device, and more particularly to a novel respiration rate measuring device that can measure the respiration rate by measuring the pulsation of the human body. .

As a physiological phenomenon, it is known that breathing causes irregularities in pulse rate. In other words, the pulse is small and fast during inspiration, and becomes slow and large during expiration, and is generally referred to as respiratory arrhythmia. This respiratory arrhythmia has been known for a long time among medical professionals such as doctors (this is considered to be one of the first auxiliary diagnostic tools for determining some diseases, and is usually observed during inspiration). It is considered pathological when the pulse rate during expiration is approximately twice as high as the pulse rate during expiration.

In this way, it is known among experts in a particular field that there is a certain relationship between breathing and respiratory arrhythmia, but as mentioned above, conventionally, respiratory The reality is that arrhythmia is only used as an aid or a means of diagnosing certain diseases, and no other uses are considered.

However, while studying the relationship between the above-mentioned respiration and the occurrence of the associated λ respiratory arrhythmia, the present inventors discovered that the pulse period accompanying respiratory arrhythmia fluctuates in synchronization with respiration with an f periodicity. I came up with the idea that it might be possible to measure the respiratory rate by utilizing the periodic fluctuations in the pulse cycle that accompany this respiratory arrhythmia.

The present invention was made based on such knowledge and ideas.
The purpose of this device is to measure the respiratory rate by measuring the cycle of pulses associated with respiratory arrhythmia, and by measuring the cycle of the human body's pulsations in synchronization with this cycle. The purpose of this invention is to provide a measuring device.

In order to achieve the objective, the respiration rate measuring device according to the present invention includes (a) a pulsation sensor that detects the pulsation of the human body and outputs a pulsation signal representing the pulsation; (C) period determination means for determining the period of the pulsation signal based on the pulsation signal; and (C) a period determining means that continuously corresponds to each of the pulsation signals based on the period determined by the period determination means. Variation (lZ &
and (d) a display device for displaying the number of breaths per unit time by displaying the number of changes per unit time determined by the number of changes determining means. This is it.

That is, in the present invention, since respiratory arrhythmia appears due to non-periodic heartbeats caused by breathing, the concept of respiratory arrhythmia is not limited to what appears in pulses, but also applies to human body beats. As shown in the claim correspondence chart in Figure 1, the pulsation of the human body is determined in beats, and the number of periodic changes in the circumference KA is calculated as a change per unit time. Determine by number determining means,
By displaying the calculated number of changes per unit time as the respiration rate on a display device, the respiration rate can be recognized at a glance.

According to the present invention, the Korotkoff sound (cK sound) generated in the arteries based on the pulsation of the heart and the pulse wave as cuff vibration mj, which are measured by a so-called blood pressure measuring device,
Alternatively, the respiratory rate is measured by measuring the heartbeat of the human body whose generation cycle is synchronized with the pulse accompanied by respiratory arrhythmia, such as an electrocardiographic signal accompanying the contraction of the cardiac muscle that is the object of measurement when creating an electrocardiogram. is possible.

In the present invention, as described above, the blood pressure measuring device measures a pulse wave as sound or cuff vibration, and t measures an electrocardiographic signal of the myocardium, which is a subject to be measured when creating an electrocardiogram. Since the respiration rate can be measured by this method, the sensor of the blood pressure measuring device or the sensor of the electrocardiograph can be used as a sensor during the measurement of the respiration rate, and especially when these devices and the respiration rate measuring device are used at the same time. In some cases, the sensor can be shared, which is extremely convenient in practice.

Incidentally, in the past, various respiratory rate constant devices have been used, such as devices that measure the respiratory rate by attaching a thermistor as a sensor to the nostril and detecting the change in resistance due to the temperature change of the thermistor and the expansion and contraction caused by the movement of the chest. Although it is
These conventional respiration rate measuring devices require a dedicated sensor for measuring the respiration rate, so if they are used at the same time as sensors for other blood pressure measurement devices, etc., the sensor should be used by the person measuring the device. As the number of devices increases, their handling becomes extremely troublesome.

Hereinafter, embodiments in which the present invention is applied to an oscillometric blood pressure measuring device will be described in detail with reference to the drawings.

In Figure 2, °2 is a bag-shaped cuff that is attached to a part of the human body and presses the part, and the cuff 2 detects the pressure inside the cuff 2 and displays the pressure A pressure sensor 4 that outputs a pressure signal SP is connected, and the pressure signal SP is transmitted to a pulsation detector 6 and an A/D converter 8.
supplied to The beat detection 456 is composed of a bandpass filter and an A/D converter, and the pressure signal S
The pulse wave signal sM representing the magnitude of the pulse wave is detected in synchronization with the pulse wave. and supplies it to I10 ports 1-10.

The A/D converter 8 is equipped with a low-pass filter, and digitally encodes the pressure signal SP and converts it into a pressure value signal 5PI).
and output it to the I10 boat 10. On the other hand, T start push buttons 12 for instructing the start of measurement are provided, and when the start push buttons 12 are suppressed, a start push button signal SS is supplied to the I10 port 10.

I10 port 10 connects the CPU via the data bus line.
(Arithmetic processing unit) 14. It is connected to the RAM 16 and ROM 18, and the pressure value 1 is set according to instructions from the CPU 14.
"7: @SPD, pulse wave signal SM and start signal SS are supplied to the data bus line.

The CPU 14 executes signal processing using the temporary storage function of the AM 16 according to the program stored in the ROM 18 in advance, and sends the pump movement signal SA and the displacement signal SE to the pump drive device 20 and In addition to supplying the signal to the flow rate adjustment device 22, the predetermined blood pressure value and respiration rate determined by signal processing are supplied to the display device 24 as a display signal DIJ, and the numerical display is displayed in analog form.

The pump drive device 20 consists of an electric pump connected to the cuff 2 and a drive circuit that supplies power to the electric pump, and drives the electric pump while the pump drive signal SA is being supplied to the cuff. Air is pumped into 2. On the other hand, the flow rate adjustment device 22 is provided with two electromagnetic valves, a rapid exhaust valve and a constant speed exhaust valve, which lie on the cuff 2, and output a discharge amount signal S.
By controlling the opening and closing of these exhaust valves according to the contents of E, the amount of air discharged from the cuff 2 is adjusted.

The operation of this embodiment will be explained below.

When a power switch (not shown) is turned on, power is supplied to the bottom of the device, and the CPU 14 performs control operations according to the flowchart of FIG. 3 showing the main program stored in the ROM 18 in advance.

- First, step S1 is executed, and the operating state of the start push button 12 is determined. While the start push button 12 is not pressed, step S1 is repeated, but blood pressure measurement and respiration rate itl! When the start push button 12 is depressed and the start signal SS is generated immediately after the start of the I-setting, the next steps S2 and S3 are executed. Step S
2, the flow rate adjustment device 2 is controlled by the discharge amount signal SE.
2 are closed, and the pump drive device 20 is closed.
A pump drive signal SA is supplied to the cuff 2, and the pumping of air into the cuff 2 is started. Then, in step S8, it is determined whether or not the actual pressure P in the cuff 2 represented by the pressure value signal 8PD is greater than the preset target upper limit pressure PM, and the actual pressure P is the target minus the upper limit pressure P. M,,E
This step S3 is repeated as long as the value is small. If the actual pressure P exceeds the target upper limit pressure PM, step S4 is immediately executed, and the supply of the pump drive signal SA to the pump drive device 20 is stopped to prevent air from entering the cuff 2. At the same time as the pressure feeding is stopped, the content of the evacuation amount signal SE is changed, the constant speed exhaust gas is opened, and thereafter, the air in the cuff 2 is gradually ejected. Then, in the process where the air inside the cuff 2 is gradually exhausted and the pressure P inside the cuff 2 is gradually reduced, steps 85 and subsequent steps are carried out to obtain a predetermined blood pressure value and respiration rate. .

That is, in step 85, a pulse wave peak value determination routine is executed in accordance with a program (not shown);
The peak value of each pulse wave signal 8M is obtained in synchronization with each pulse wave, and in step s6t, which is executed subsequently, the first pulse wave signal The peak value A1 of 8M is compared with the peak value ΔC1-1> of the previous (i-1)th pulse wave signal SM,
While the peak value A1 is larger than the previous peak value A (i - g, step S7 is executed, and the peak value Ai is larger than the previous peak value A
When t becomes smaller than (i-+), step S8 is executed.

In step 87, the peak value of each pulse wave signal SM obtained in step S5 and those peak values (corresponding to
The pressure P in the cuff 2 at this point, and the interval between each peak,
That is, the period between each pulse wave is stored in the liAM 16, and after step 87 is completed, S6 is executed again. That is, the peak value Ai is the peak value A
Steps S6 and S7 are repeatedly executed while the value is larger than (i-1). On the other hand, in step S8,
When the peak value Ai becomes smaller than the peak value A<i-t), the value of the peak value A(i-1) at this time, that is, the maximum peak value among the series of peak values of the pulse wave signal SM. (The peak value of the pulse wave signal SM generally increases gradually after the start of blood pressure measurement, reaches a maximum at an intermediate point, and gradually decreases after one point.).

Immediately after step S8 is executed, step S9 is executed. In step S9, the peak value Ai obtained in step S5 is compared with a predetermined target minimum peak value Ao, which is sufficiently small, to obtain all the pulse wave data necessary to calculate the predetermined blood pressure value. It is determined whether or not the current condition is present. Then, the peak value Ai is still the target minimum peak value Ao
When it is determined that the larger, necessary data is not yet available, step slO is immediately executed, and when it is determined that the data is complete, step all is immediately executed. In step S10, similar to step S7, various pulse wave data are stored in the RAM 16, and after that, step S9 is executed again, and it is determined that the peak value Ai is smaller than the target minimum peak 1 axis Ao. Step S9 and Step 81 until
0 is executed repeatedly.

On the other hand, in step S11, the contents of the evacuation green signal SE are changed, and the rapid evacuation valve, which had been closed until then, is opened, and the air in the cuff 2 is rapidly ejected.

After executing step 811, step S12 and Sta
is executed immediately. That is, in step 812, a blood pressure value determination routine is executed to calculate the systolic blood pressure value and the diastolic blood pressure value, and in step 818, the number of respirations per unit time is determined. In addition,
The systolic blood pressure value and the diastolic blood pressure value are stored in step 88 and calculated based on the maximum peak value of the pulse wave signal 8M, and are usually obtained before the maximum peak value is obtained. (peak value stored in S7)
A peak value having a predetermined ratio to the maximum peak value is obtained, and the pressure P inside the cuff 2 is taken as the systolic blood pressure value, and the maximum peak value is obtained. The pressure P in the cuff 2 when a peak value that is preset to the maximum peak value and less than 1 ratio is obtained among the values (the peak values stored in step S10) is determined as the diastolic blood pressure value. .

The respiration rate determination routine in step s18 is executed according to the flowchart shown in FIG.

That is, when the program of the respiration rate determination routine is started, first, the pulse wave period difference calculation routine of step SR1 is executed. In this pulse wave period difference calculation routine, t i −t(i − 1> calculation is performed, and the material for determining whether the inter-pulse wave period 1 is expanding or narrowing, that is, the material for determining whether breathing is in an exhalation state or an inhalation state is obtained.

Then, the pulse wave period difference calculation routine (step 5RI)
Subsequently, the slope reversal number calculation routine of step SR2 is executed, and the ti- calculated in step SR1 is
Based on the sign (+, -) of the calculation result t(i-ゎ,
The number of gradient reversals, ie, sign reversals, indicating whether the period ti is widening or narrowing is calculated. Furthermore, the number of breaths per ST time will be determined.

That is, in step SR3, the number of reversals of the f-co gradient calculated in step SR2 is divided by the pulse wave measurement period 11+, and the number of respirations per unit time is determined. Note that the number of inversions of the gradient described above is determined only for either the number of inversions of the sign from 10 to - or only the number of inversions from - to +.
In TL2, both the inversion from 10 to - and the inversion from - to 10 are determined as the number of slope inversions.In this case, it is necessary to divide the number of inversions by 2T in step SR3.

In other words, when the horizontal axis is the number of respirations and the vertical axis is the length of the period ti, the interpulse wave period L1 has an approximate sine wave shape as shown in FIG. 5(a) depending on the respiration. For eggplant 1, the calculation result of the above tit-t(i-1) is the fifth
As shown in Figure (b), f
This is an approximate curve with an in-wave shape. Therefore, Fig. 5 (
As is clear from b), if you find the number of sign reversals in one direction (for example, from 10 to -), you can find the number of breaths, and if you find this for unit time, you can find the number of breaths per unit time. A number is required.

When step SR8 is executed, the respiration rate determination routine is immediately terminated, and step S14 of the main program is subsequently executed. In step S14, step 8
The blood pressure value and respiration rate obtained in steps 12 and S13 are sent to the φ display device 24 as a display signal L)D and displayed. When step s14 is executed, the main program immediately ends.

As is clear from the above description, in this embodiment, the respiration rate is measured based on the pulse wave, which is synchronized with the heartbeat detected by an oscillometric blood pressure measuring device and is the vibration of the f-column artery. There is. That is, in this embodiment, cuff 2. of the blood pressure measuring device. A pulsation sensor is constructed by combining the pressure sensor 4 and the pulsation detector 6, and this pulsation sensor detects a pulse wave, which is the pulsation of the human body, and thereby outputs a pulse wave signal 8M, which is a pulsation signal. That's what I'm trying to do. In this case, there is no particular need to provide a separate pulsation sensor as a respiration rate measuring device.

Further, in this embodiment, the period between each pulse wave signal 8M is determined in steps S7 and S9 based on the peak value determined in the pulse wave peak value determination routine in step S5.
The period between the peak values is stored as an interpulse wave period, that is, a pulsation period, and based on this stored period, the number of changes in the pulsation period is calculated as the number of reversals of the period gradient in the respiration rate determination routine of step 813. is calculated, and the number of changes per unit time is also calculated. The number of changes per unit time, ie, the number of reversals of the periodic slope, is displayed on the display device 24 as the respiration rate. That is, in this embodiment, step 85'+87 and 89 constitute a period determining means that determines the period of the pulse wave signal corresponding to the pulsation signal f. A change number determining means is configured to determine the number of periodic changes per unit time s in the period of the pulse wave signal of the dynamic signal f.

Although one embodiment of the present invention has been described above, this is just one embodiment, and it goes without saying that the present invention can be implemented in other embodiments.

For example, in the embodiment described above, in order to determine the period between each pulse wave signal (pulsation signal), the peak of each pulse wave signal is detected, and the interval between the peaks is determined as the period between each pulse wave signal. There is no equivalent problem even if the determining device detects the rising edge of each pulse wave signal and determines the interval between the rising edges of each signal as a period. If it is a part that is synchronized with the pulsation of the signal and has an f period, it is possible to determine the interval between the parts of each signal as the period between each signal.

In addition, in the above embodiment, the number of periodic changes in the period between the pulse wave signals synchronized with respiration is determined by the period ti between the first pulse wave signal and the period Jl of the 1-1st period. 1)
The number of changes can be found by calculating i - Jl 1) between the results and finding the number of inversions of the sign of -, but the above calculation is not necessarily performed. It is not necessary, as shown in Fig. 5(a), the near υ function of the abbreviated in waveform is found by interpolation, the near tJ function is differentiated to find its extreme value, and one of The number of maximum values or minimum values may be used as the number of changes. In addition, since this time,
FIG. 6 shows a flowchart of the program of the respiration rate determination routine (step 813) for calculating the respiration rate. That is, in FIG. 6 (here, step 8
In R'1, an approximation function F(t) is obtained by using the interpolation method, and in step SR'2, this approximation function F(t
) is differentiated to find its tangent value, step S11
'8, the number of extreme values is divided into two to obtain the number of changes, and this number of changes is converted to the number of respirations per unit time in step SR3.

Furthermore, in the embodiment described above, the respiration rate and blood pressure value are measured automatically based on the pressing operation of the start button 12, but they are continuously and automatically measured. It is also possible to configure the system so that a predetermined blood pressure value is simultaneously calculated along with the respiration rate, but it is of course possible to configure the system to calculate the respiration rate at the same time. Regarding display devices, there are various known display devices such as a digital display device that displays numerical values, a printer display device that prints out on recording paper with a printer, or an analog display device that displays graphs on recording paper. Of course, it can be used.

In addition, the respiratory rate measuring device according to the present invention is applicable not only to the oscillometric blood pressure measuring device of the above embodiment, but also to a microphone-type blood pressure measuring device that measures blood pressure based on the Korotkoff sound generated in the artery by tightening the cuff. equipment,
It is also called an ultrasonic blood pressure measuring device, in which ultrasonic waves are tightened with a cuff and emitted toward an artery, and the blood pressure is measured based on the reflected waves by receiving Doppler displacement caused by the vibration of the arterial surface wall. The sensor can be shared, and furthermore, it can be shared with the sensor of an electrocardiograph that creates an electrocardiogram. In short, the respiration rate measuring device according to the present invention is applicable to various devices having a sensor capable of detecting the pulsation of the human body. Since there is no need to place the sensor around the nostrils or chest like in the respiration rate measuring device, there is an advantage that the discomfort caused by the sensor to the person to be measured is greatly reduced.

In addition, although not listed, various modifications may be made without departing from the spirit of the present invention.

It goes without saying that the present invention can be implemented in a single manner with improvements.

[Brief explanation of drawings]

FIG. 1 is a diagram corresponding to the claims of the respiration rate measuring device according to the present invention, and FIG. 2 is a diagram showing the respiration rate measurement according to the present invention in which the pulsation sensor is shared with the sensor of the oscillometric blood pressure measuring device. FIG. 2 is a block diagram showing one embodiment of the device along with a blood pressure value measuring device. FIG. 8 is a flowchart of a one-shot main program for explaining the operation of the apparatus shown in FIG. 2, and FIG. 4 is a flowchart of a program for the respiration rate determination routine shown in FIG. Figure 5 (a) is a graph that explains the relationship between respiration and pulse wave period using an approximate curve. This is a graph that explains the relationship between the difference and respiration using a near curve. FIG. 6 is a diagram corresponding to FIG. 4 showing another example of the respiration rate determination routine of FIG. 3. 14: CPU (processing unit) 16: RAM 18: ROM 24: Display device applicant Nippon Kolin Co., Ltd.

Claims (1)

[Scope of Claims] A pulsation sensor that detects the pulsation of a human body and outputs a pulsation signal representing the pulsation; a period determining means for determining the period of the pulsation signal based on the pulsation signal; a change number determining means for determining the number of changes per unit time in the period corresponding to each of the continuous pulsation signals (based on this); By displaying the number of winning changes,
1. A respiration rate measuring device comprising: a display device that displays the respiration rate per unit time.