JP2551668B2 - Electronic blood pressure monitor - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electronic sphygmomanometer, and more particularly to an electronic sphygmomanometer equipped with both the Korotkoff method and the oscillometric method.

[Prior Art] Conventionally, as a measurement method using this type of electronic blood pressure monitor, in order to perform nozzle discrimination of Korotkoff sound, a cuff oscillating arterial wave synchronized with this is detected, a gate is opened, and it enters into this gate. There are a method in which only the Korotkoff sound detection signal is detected as a Korotkoff sound, and a method in which the optimum value is determined based on the measurement result after measuring blood pressure by both methods. However, when blood pressure measurement based on the cuff oscillating artery wave is performed when the cuff oscillating artery wave is small, a large error occurs in the measurement result. Therefore, in the blood pressure monitor of the oscillometric method,
When the pressure is reduced by a certain value or more after the decompression is started until the first pulse wave is detected, it is determined that the pulse wave is small and the blood pressure measurement is stopped.

[Problems to be Solved by the Invention] However, in an electronic sphygmomanometer equipped with both the Korotkoff method and the oscillometric method, no solution has been taken when the cuff vibration arterial wave is small. Therefore, in the case of performing noise discrimination of Korotkoff sound by the cuff swing arterial wave, the detected cuff when the individual difference of the living body or the cuff is loosely wound, or when a slightly large cuff is wrapped around a thin arm. When the swing wave is small, the systolic blood pressure is measured lower than the actual value, and the systolic blood pressure is measured higher than the actual value. On the other hand, when the oscillometric method is performed with such a small cuff arterial wave, a large error similarly occurs. Further, according to the conventional determination condition of the cuff oscillating artery wave, there is a disadvantage that the cuff oscillating artery wave is determined to be small when the pressurization is large, although not actually small.

The present invention provides an electronic sphygmomanometer that eliminates the above-mentioned conventional drawbacks, accurately determines that a cuff oscillating artery wave is small, and eliminates a measurement error due to a small cuff oscillating artery wave.

Here, in the case of performing noise discrimination of Korotkoff sound by the cuff oscillating arterial wave, if the noise discrimination by the cuff oscillating arterial wave is stopped when the cuff oscillating arterial wave is small, it is likely to be affected by noise. Further, if the time interval is set based on the cycle of the pulse detected so far, for example, when the time interval is 0.3 × T to 1.7 × T in the average cycle T detected so far, a light single arrhythmia and Fluctuations due to breathing (+
If it occurs, the Korotkoff sounds cannot be detected, resulting in an error in the measurement of diastolic blood pressure. In other words, the pulsation cycle of breathing (deep breath or swelling) may suddenly reach about 60%, and the pulsation cycle becomes considerably large at the beginning and end of blood pressure measurement. There are cases. Further, in the case of a single arrhythmia, which is relatively common, the rhythm shifts due to the arrhythmia, and the previous periodicity cannot be used.

Therefore, the present invention further accurately determines that the cuff oscillating arterial wave is small, and eliminates the measurement error due to the small cuff oscillating arterial wave, and the measurement error of the diastolic blood pressure due to fluctuations due to mild single arrhythmia and respiration. We provide an electronic blood pressure monitor that eliminates this.

[Means for Solving the Problem] In order to solve this problem, the electronic sphygmomanometer of the present invention comprises:
The Korotkoff method, which measures blood pressure based on the occurrence or disappearance of Korotkoff sound generated by compressing a part of the living body with the cuff, and the magnitude of the magnitude of the cuff vibration arterial wave superimposed on the pressure of the cuff depending on the time phase An electronic sphygmomanometer equipped with both oscillometric methods for measuring blood pressure based on changes, when the number of cuff vibration arterial waves detected up to the first Korotkoff sound detected is less than a predetermined number. The cuff oscillating arterial wave measuring means for stopping the measurement of the cuff oscillating arterial wave, and the systolic blood pressure determining means for performing a search retroactively to the Korotkoff sound detected up to now to determine whether or not the systolic blood pressure. It is characterized by being provided.

Further, the electronic sphygmomanometer of the present invention is a Korotkoff method for measuring blood pressure based on the occurrence or disappearance of Korotkoff sound generated by compressing a part of a living body with a cuff, and a cuff superimposed on the pressure of the cuff. An electronic sphygmomanometer equipped with both oscillometric methods for measuring blood pressure based on changes in the magnitude of the pulsation arterial wave based on the time phase, and based on the swaying arterial wave of the cuff when decompressing the cuff, produces Korotkoff sounds. First time zone setting means for setting a time zone to be recognized, and a predetermined number of cuff vibrating arterial waves set by the first time zone setting means and detected up to the first Korotkoff sound detected. When it is less than the number, the time zone setting canceling means for canceling the time zone setting by the first time zone setting means is provided.

A second time zone setting means for setting a time zone of a predetermined time width for recognizing the next Korotkoff sound for each recognition of the Korotkoff sound is further provided, and the time period set by the first time zone setting means by the time zone setting means. If the obi setting is canceled,
Another time zone is set by the second time zone setting means.

[Operation] In such a configuration, the cuff vibration arterial wave is small by using the cuff vibration arterial wave for the gate of Korotkoff sound and determining whether or not to perform the oscillometric method at the time when the systolic blood pressure is recognized. This was accurately determined, and the measurement error due to the small cuff pulsation arterial wave was eliminated.

Furthermore, by providing a means to set the time zone for recognizing the next Korotkoff sound with a predetermined time width for each recognition of Korotkoff sound, noise detection in the detection of only Korotkoff sound is performed, and a light single arrhythmia is detected. And the measurement error of the minimum blood pressure due to the fluctuation of breathing was eliminated.

Embodiment FIG. 1 is a block diagram showing a configuration of a characteristic portion of an electronic blood pressure monitor of the present embodiment. Note that a cuff pressurization / decompression controller, a power supply, and the like are not shown. The output signals of each block are shown in FIG.

Reference numeral 10 denotes a Korotkoff sound (K sound) measuring unit, which includes a microphone 11 for collecting blood flow sounds and an amplifier 12 for amplifying an output voltage.
And an A / D converter 14 and a bandpass filter 13 that transmits a predetermined band corresponding to the Korotkoff sound.
Is output. Here, the amplifier 12 preferably amplifies a predetermined band. Reference numeral 20 denotes a cuff pressure / pulse wave measuring unit, which includes a pressure sensor 21, an amplifier 22, and an A / D converter 23, and outputs output data 80.

30 is the output data from the above Korotkoff sound measuring unit 83
Is a control unit for recognizing the systolic blood pressure and the diastolic blood pressure based on the threshold level 82 in the gate 81 created by the output data 80 from the cuff pressure / pulse wave measuring unit 20. And RO that stores the control program of CPU31
It comprises an M32, a RAM 33 for auxiliary storage and input data storage, and input or output interfaces 34, 35. CPU31
Flag _{S 1, S 2, D 1} , D 2 have the (31 a to 31 d), RAM 33 is DIA _1, the last storing the diastolic blood pressure of SYS ₁ for storing the systolic blood pressure value based on the pulse wave gate Memorize systolic blood pressure value based on the time width from Korotkoff sounds.Remember SYS ₂ and diastolic blood pressure.
It has DIA ₂ (33a to 33d). Reference numeral 40 is a liquid crystal display or the like for displaying the measurement result, 50 is a key input section for inputting an operator's instruction, and has a power switch 51 and the like.

From the pressure signal 80 input from the pressure sensor 21 and converted into a digital value by the A / D converter 23, the gate 8 for recognizing Korotkoff sound is obtained by the minimum point 80a and the next same-level point 80b.
Create 1. In this gate 81, a Korotkoff sound is extracted by comparing a digital signal 83 input from the microphone 11 via the A / D converter 14 with a predetermined threshold level 82. On the other hand, even outside the gate 84, the predetermined threshold level
Noise is extracted by comparison with 82. Here, the loudness (peak and bottom) of the Korotkoff sound is measured from the digital signal from the Korotkoff sound detection unit, and this loudness is a certain value or more, and it is superposed on this from the digital signal from the pressure detection unit. When the cuff oscillating arterial wave that exists is recognized and the gate is opened by this and it enters into this gate, it is detected that there is a Korotkoff sound signal.

On the other hand, in the above method, the cuff pressure value at the timing of the Korotkoff sound detected first when the Korotkoff sound is detected for two consecutive beats is recognized as the systolic blood pressure. In parallel with the recognition of the systolic blood pressure, if a digital signal from the Korotkoff detection exceeds a certain threshold value, and, for example, 3
The Korotkoff sound recognition method is performed in which the systolic blood pressure recognition condition is that the intervals of the detected signals are within 0.35 to 2 seconds.

If the systolic blood pressure is recognized under the former condition, the cuff pressure value at the timing of systolic blood pressure will be 30 mm after starting decompression.
When decompressing by Hg or more, and the cuff pulsating arterial wave at the timing of systolic blood pressure is the third night or more after the cuff oscillating arterial wave was first recognized, the data by the latter method is used effectively in the work area. The Korotkoff sound is continuously recognized using the gate by the cuff oscillating arterial wave as it is, and when the Korotkoff sound is not recognized for two consecutive beats, the cuff pressure value at the timing of the last recognized Korotkoff sound is set to the minimum. Blood pressure value.

However, if the systolic blood pressure is recognized, the cuff pressure value at the systolic blood pressure timing starts decompression and is decompressed by 30 mmHg or more, and the cuff vibration arterial wave at the systolic blood pressure timing is recognized first. If it is within the second beat since it was performed, it is judged that the pulse wave is too small to be reliable and the detection of Korotkoff sound at the gate by the cuff vibration arterial wave is stopped, and the detection by only Korotkoff sound described above is stopped. Continuing on, the systolic blood pressure is searched back to the Korotkoff sound detected so far, and the cuff pressure value at the first timing at which two consecutive beats are detected is taken as the systolic blood pressure value. However, if the pressure value at this timing has not dropped by 30 mmHg from the start of depressurization of the cuff, the systolic blood pressure is not measured and "insufficient pressurization" is notified and only the diastolic blood pressure is recognized. When the Korotkoff sound is continuously recognized for 4 seconds and the Korotkoff sound is not recognized, the cuff pressure value at the timing of the last beat is set as the minimum blood pressure.

In addition, even if no pulse wave can be recognized and the cuff pressure reaches 30 mmHg or less, blood pressure is naturally measured by the blood pressure recognition method using only Korotkoff sounds.

Here, the conditions of the gate when the pulse wave gate is not used are set as follows. When looking at the continuity of Korotkoff sounds in an adult sphygmomanometer, the gate at the interval of the pulse rate (30 beats / minute to 200 beats / minute) that is usually considered based on the previously detected beats, that is, the previous Korotkoff sounds
Open the gate for 0.3 to 2 seconds and detect Korotkoff sounds in this gate. Also, from the Korotkov sound that was recognized last
If no Korotkoff sound is detected for 4 seconds, which is twice as long as 2 seconds, which corresponds to 30 beats / minute, it is determined as the 5th point of Swan (the point at which Korotkoff sound disappears), and the cuff pressure value at this time is set to the minimum blood pressure. Recognize as a value.

3A to 3C are flow charts showing the operation procedure of the electronic sphygmomanometer of the present embodiment.

First, after the power is turned on, the blood pressure monitor is initialized in step S31, for example, the flags S ₁ , S ₂ , D ₁ and D ₂ are set to "0". Pressurization is started in step S32, waiting for a predetermined pressure to be reached in step S33, and depressurization is started in step S34. As the pressure is reduced, Korotkoff sound recognition based on the pulse wave gate and Korotkoff sound recognition based on the time width are performed in parallel in steps S35 and S36 until it is determined in step S37 that the flag S ₁ or S _{2 is} “1”. The processing in steps S35 and S36 is shown in FIGS. 3B and 3B.
It will be described later according to FIG.

At the time when the flag S ₁ or S ₂ becomes “1”, that is, when the systolic blood pressure is found, the process proceeds from step S35-1 or step S37 to step S38, and 30 mmHg from the start of decompression.
It is checked whether or not the pressure has been reduced as described above. If the pressure has not been reduced, in step S39 it is determined that the pressure is insufficient and SYS ₁ and SYS ₂ are set to "0". If the pressure is not reduced by 30 mmHg or more, the operation jumps to step S40, and next, at step S40, it is checked whether or not the cuff vibration arterial wave has hit more than 3 beats before the systolic blood pressure is detected. If there is, go to step S41, continue Korotkoff sound recognition by the pulse wave gate, and until flag D ₁ becomes "1" at step S42,
That is, waiting for the recognition of the lowest blood pressure, the contents of SYS ₁ and DIA ₁ are displayed as the highest blood pressure and the lowest blood pressure in step S43.

On the other hand, when the cuff vibration arterial wave does not reach 3 beats until the systolic blood pressure is detected, the process proceeds from step S40 to step S44 to stop the Korotkoff sound recognition by the pulse wave gate and perform Korotkoff sound recognition based on the time width. The contents of SYS ₂ and DIA ₂ are displayed as the systolic blood pressure and the diastolic blood pressure in step S46 until the flag D ₂ becomes "1" in step S45, that is, waiting for the recognition of the diastolic blood pressure.

Then, according to FIG. 3B, step S35 and step S41
A routine for Korotkoff sound recognition by the pulse wave gate will be described.

Step S51 a flag S ₁ or S ₂ is whether a "1", that is, a checking whether systolic blood pressure is recognized. If it still does not reach "1", check whether two consecutive Korotkoff sounds are recognized in step S52, and if recognized, store the current cuff pressure in SYS ₁ in step S53, and then press step S54. Then set flag S ₁ to "1" and return.
If not recognized, the process returns from step S52. On the other hand, if either flag is set to "1", step
In S55, check the condition that there is no Korotkoff sound continuously, and if not, proceed to Step S56 to store the minimum blood pressure value in DIA ₁ , and set the flag D ₁ to "1" in Step S57. To return. If the above conditions are not satisfied, the process returns from step S55.

FIG. 3C is a Korotkoff sound recognition routine based on the time width of steps S36 and S44. This routine performs Korotkoff sound recognition in the time zone of 0.35 seconds to 2 seconds since the last Korotkoff sound recognition, and sets systolic blood pressure value to SYS ₂ and diastolic blood pressure value to DIA _2.
Then, the flags S ₂ and D ₂ are set. The float chart is similar to Figure 3B and will not be discussed in detail here.

FIG. 4 is a diagram showing a display example of the electronic sphygmomanometer of the present embodiment, and in order to distinguish the recognition by only Korotkoff sounds from the recognition by the pulse wave gate, is displayed.

By the oscillometric method using the detected cuff vibration arterial wave, for example, the size of the pulse wave on the systolic blood pressure side is searched from the point of the maximum value of the detected cuff vibration arterial wave size. The pressure value at the point that is less than 50% of the maximum value for the first time is searched for the systolic blood pressure value of the oscillometric method. The cuff pressure value at the point when the value reaches 70% or less of the value for the first time may be used as the minimum blood pressure value of the oscillometric method, and blood pressure recognition by the oscillometric method may be performed together. The meaning of arranging the oscillometric method in parallel is that blood flow noise is generated in this part when performing arterial shunting in dialysis patients, and this noise overlaps the Korotkoff sound and frequency band. However, Korotkoff sounds are detected below the minimum blood pressure, and the minimum blood pressure cannot be recognized due to Korotkoff sounds, and the oscillometric method cannot be used. This is because the Korotkoff sound may be generated up to the pressure value below the minimum blood pressure during the same time, and similarly, there is a case where the oscillometric method has to be obtained.

In such a sphygmomanometer that uses the Korotkoff method and the oscillometric method together, the measurement by the oscillometric method is stopped under the same conditions as described above, and if it is configured to display only the measurement result by the Korotkoff sound, the The same effect as the embodiment is obtained.

As described above, the cuff vibration that occurs when the pulse is very weak as an individual difference but the K sound is heard, the cuff is wound relatively loosely, and the relatively large cuff is wound around a thin arm. When arterial waves are small, erroneous recognition of Korotkoff sounds can be avoided at the pulse wave gate using the cuff vibration arterial wave synchronism used for noise discrimination in the Korotkoff method. It is possible to avoid erroneous recognition due to the oscillometric method in the Korotkoff sphygmomanometer in which the oscillometric method that is effective as a whole is arranged in parallel.

In addition, before the systolic blood pressure recognition, the above method can be easily realized by arranging another Korotkoff sound recognition method that measures only Korotkoff sound, and it is possible to easily and accurately determine whether the pulse wave is small. .

In addition, accurate blood pressure measurement can be easily performed without being affected by respiration and a single arrhythmia, and being relatively unaffected by noise due to only Korotkoff sounds.

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide an electronic sphygmomanometer that accurately determines that the cuff oscillating arterial wave is small and eliminates the measurement error due to the small cuff oscillating artery wave.

Furthermore, the electronic blood pressure that accurately determines that the cuff oscillating arterial wave is small and eliminates the measurement error due to the small cuff oscillating arterial wave, and eliminates the measurement error of the diastolic blood pressure due to mild single arrhythmia and respiratory fluctuations. Can provide a total.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the characteristic part of the electronic sphygmomanometer of the present embodiment, FIG. 2 is a diagram showing the output signal at each block of the electronic sphygmomanometer of the present embodiment, and FIGS. 3A to 3C. Is a flow chart showing the operation procedure of the electronic sphygmomanometer of the present embodiment, and FIG. 4 is a diagram showing a display example of the electronic sphygmomanometer of the present embodiment. In the figure, 10 ... Korotkoff sound measuring unit, 11 ... Microphone, 12 ... Amplifier, 13 ... Bandpass filter, 14 ...
A / D converter, 20 ... Cuff pressure / pulse wave measurement unit, 21 ... Pressure sensor, 22 ... Amplifier, 23 ... A / D converter, 30 ... Korotkoff sound measuring device, 31 ... CPU, 31a …… Flag S ₁ , 31b ……
Flag S ₂ , 31c …… Flag D ₁ , 31d …… Flag D ₂ , 32 ……
ROM, 33 …… RAM, 33a …… SYS ₁ , 33b …… SYS ₂ , 33c …… D
IA ₁ , 33d …… DIA ₂ , 34,35 …… Interface, 40 ……
Display unit, 50 ... Key input unit.

Claims (3)

(57) [Claims] 1. A Korotkoff method for measuring blood pressure based on the occurrence or disappearance of Korotkoff sounds generated by pressing a part of a living body with a cuff, and a cuff vibration arterial wave superposed on the pressure of the cuff. An electronic sphygmomanometer equipped with both of the oscillometric method for measuring blood pressure based on the change in magnitude depending on the phase, and the number of cuff vibration arterial waves detected up to the first Korotkoff sound detected is a predetermined number. If it is less than, the cuff oscillating arterial wave measuring means for stopping the measurement of the cuff oscillating arterial wave, and the systolic blood pressure to determine whether it is the systolic blood pressure by tracing back to the Korotkoff sound detected so far An electronic sphygmomanometer, comprising: a determining unit. 2. A Korotkoff method for measuring blood pressure based on the occurrence or disappearance of Korotkoff sounds generated by compressing a part of a living body with a cuff, and a cuff vibration arterial wave superposed on the pressure of the cuff. An electronic sphygmomanometer equipped with both of the oscillometric method for measuring blood pressure based on the change in magnitude depending on the phase, and the time period for recognizing Korotkoff sounds based on the swaying arterial wave of the cuff when decompressing the cuff. First time zone setting means for setting,
When the number of cuff vibration arterial waves detected by the first Korotkoff sound set by the first time zone setting means is less than a predetermined number, the first time zone setting means is used. An electronic sphygmomanometer, comprising: time zone setting canceling means for canceling time zone setting. 3. A second time zone setting means for setting a time zone of a predetermined time width for recognizing the next Korotkoff sound for each recognition of the Korotkoff sound, further comprising: second time zone setting means, wherein the first time zone is set by the time zone setting means. The electronic sphygmomanometer according to claim 2, wherein when the setting of the time zone by the setting means is stopped, the second time zone setting means sets another time zone.