JPH0311220B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention uses a vibration method (oscillometric method) that extracts and calculates arterial pulse wave components for each heartbeat superimposed on cuff pressure to measure systolic and diastolic blood pressure values. ) concerning electronic blood pressure monitors.

[Background Art] Conventionally, in this type of electronic sphygmomanometer using a vibration method in which the arterial pulse wave component superimposed on the cuff pressure is extracted and the maximum and diastolic blood pressure values are determined based on the change, the cuff gradually changes. All arterial pulse wave values from the appearance of the arterial pulse wave during exhaustion until the maximum value of the arterial pulse wave value is determined must be stored in the storage means, and a one-chip microcomputer is used as the blood pressure determination means. When using , a disadvantage is that an expensive device with a large memory capacity must be used. In addition, if the subject's pulse is fast (for example, in the case of an infant, the pulse rate is 120 beats/min), or if the difference between the systolic blood pressure and the mean blood pressure is large, the memory capacity may become insufficient. There was a problem that measurement became impossible. Furthermore, it is necessary to perform many comparison calculations to detect the time of appearance of the arterial pulse wave value at a predetermined ratio with respect to the maximum value of the arterial pulse wave value, that is, the time of systolic blood pressure, which takes a long calculation time and increases blood pressure. There was a problem that the waiting time until the measurement results were displayed was long.

[Object of the Invention] The present invention has been made in view of the above points, and its purpose is to reduce the memory capacity of the storage means, to reduce the size and cost, Moreover, it is an object of the present invention to provide an electronic blood pressure monitor that can simplify blood pressure determination calculations and quickly display blood pressure measurement results.

[Disclosure of the Invention] (Structure) The present invention provides a cuff that is attached to the main part of a subject to prevent blood flow, a pressurizing means that increases the pressure inside the cuff,
An exhaust means for gradually lowering the pressure inside the cuff, a pressure sensor for converting the pressure inside the cuff into an electrical signal, a pressure information separation means for extracting an arterial pulse wave value and a cuff pressure value from the pressure sensor output, and a pressure information separation means for extracting an arterial pulse wave value and a cuff pressure value from the pressure sensor output. The maximum
It is composed of a blood pressure determining means for determining the diastolic blood pressure value and a display means for displaying both determined blood pressure values, and the arterial pulse wave value is initially set to the judgment boundary value obtained by multiplying the maximum value of the arterial pulse wave value by a predetermined ratio. A new arterial pulse wave value is extracted in an electronic sphygmomanometer comprising a systolic blood pressure determining means of a blood pressure determining means so as to determine the time when the cuff pressure begins to exceed the systolic blood pressure as the systolic blood pressure. Each time the arterial pulse wave value and cuff pressure value begin to exceed the temporary judgment boundary value, which is calculated by multiplying the provisional maximum value, which is the maximum value of the already stored arterial pulse wave values, by a predetermined ratio, the arterial pulse wave value and cuff pressure value are deleted. By forming the storage means in such a manner, the memory capacity of the storage means can be reduced, the size and cost can be reduced, and calculations for blood pressure determination can be simplified and blood pressure measurement results can be displayed quickly. This is how it was done.

(Example 1) Figures 1 to 3 show the basic configuration of an example of the present invention, and show the main part of the subject (for example, the upper arm).
a cuff 2 attached to the cuff 1 for blood ischemia; a pressurizing means 3 consisting of a pressurizing rubber ball that increases the pressure within the cuff 2;
Exhaust means 4 that gradually lowers the pressure inside the cuff 2
, a pressure sensor 5 that converts the pressure inside the cuff 2 into an electrical signal, a low-pass filter 6 that removes noise signals from the output of the pressure sensor 5, and an A/D converter that samples the output of the low-pass filter 6 and converts it into a digital value. 7, and A/D gradually during the exhaust period.
Arterial pulse wave extraction means 8a extracts an arterial pulse wave value V by digital calculation from the pressure value (digital value) output from the converter 7, and extracts a cuff pressure value P by removing the arterial pulse wave from the pressure value by digital calculation. Pressure information separation means 9 equipped with cuff pressure extraction means 8b; storage means 10 for storing arterial pulse wave values V and cuff pressure values P corresponding to the pulse waves extracted by pressure information separation means 9; A calculating means 11 for appropriately reading and comparing values stored in the calculating means 11, and a blood pressure determining means 12 for determining the maximum and diastolic blood pressure values from the calculation results calculated by the calculating means 11.
blood pressure determination means 13 consisting of; maximum and diastolic blood pressure values and pumping speed determined by the blood pressure determining means 13; pumping speed values and pulse values output from the pulse monitor 14; and cuff pressure output from the cuff pressure monitor 15. The display means 16 displays the blood pressure as appropriate, and the operation switch section 17 for controlling the blood pressure measurement operation and the display means 16 are arranged on the front side of the blood pressure monitor main body 30. Here, the pressure information separation means 9, the storage means 10, the calculation means 11, the blood pressure determination means 13, and both monitors 14 and 15 are implemented by a microcomputer 1 using a CPU, ROM, RAM, etc.
8.

The basic operation of the first embodiment is as follows. Now, the cuff 2 is attached to the upper arm 1 of the person to be measured, and by appropriately pressurizing and depressurizing with the pressurizing means 3 and the exhaust means 4, arterial ischemia is achieved, and the arterial counter pressure at the time of opening is reduced by cuff 2. The cuff pressure signal is transferred to the pressure sensor 5 by air conduction through the tube 21, and electrically converted together with the static pressure (cuff pressure) to obtain an internal cuff pressure signal consisting of an analog signal as shown in FIG. 6a. Next, after filtering this cuff internal pressure signal as much as possible using a low-pass filter 6, the pressure value converted into a digital value by an A/D converter 7 is sent to a microcomputer 1.
Sent to 8th. In microcomputer 18,
The information separating means 9 separates and extracts the arterial pulse wave component and the cuff pressure component, which are seen as a phenomenon of arterial counterpressure, from the pressure value output from the A/D converter 7, and the extracted arterial pulse wave value V and The cuff pressure value P is stored in the storage means 10, and the calculation means 11 of the blood pressure determination means 13 performs a comparison calculation,
The blood pressure determining means 12 determines the systolic blood pressure period and the diastolic blood pressure period, and at the same time reads the cuff pressure value P corresponding to the maximum and diastolic blood pressure period from the storage means 10, and displays this cuff pressure value P as the maximum and diastolic blood pressure value. Means 1
6. Here, the best
The diastolic blood pressure timing is determined based on the highest and lowest judgment boundary values V〓(α×Vmax), V〓(β×Vmax) obtained by multiplying the maximum value Vmax of the arterial pulse wave value V by a predetermined ratio α, β. , as shown in Fig. 6b, the systolic blood pressure period is the period when the arterial pulse wave value V begins to exceed the maximum determination boundary value V〓, and the diastolic blood pressure period is the period after the maximum value Vmax of the arterial pulse wave value V. This is the time when the arterial pulse wave value V becomes less than or equal to the lowest judgment boundary value V.

By the way, the predetermined ratios α and β are determined as follows.

First, the true blood pressure information (maximum and diastolic blood pressure values) that is statistically calculated by actually performing clinical measurements by a doctor under certain measurement conditions is obtained.

Next, the electronic blood pressure monitor measures blood pressure under certain measurement conditions, and the pressure information separation means obtains information on the arterial pulse wave value.

Then, the true blood pressure value information and the arterial pulse wave value are compared, the arterial pulse wave value that is the maximum and diastolic blood pressure value is found, the ratio between this value and the maximum arterial pulse wave value is calculated, and this ratio is Let the predetermined ratios be α and β. The predetermined ratios α and β thus determined are set in advance as constants in the calculation program of the calculation means 11.

Note that the predetermined ratios α and β are influenced by the measurement site, cuff structure, air capacity, pressure information separation means, pressure sensor, etc., and different types of blood pressure monitors have different values (unique values).

FIG. 4 shows a specific example of the configuration of the storage means 10, in which the storage area is a storage area 1 for arterial pulse wave values V.
0a, storage area 10b of cuff pressure value P and maximum value
It has a storage area 10c of Vmax, and each of the storage areas 10a and 10b can store 10 pairs of data (data for 10 beats).

Here, in this embodiment, this storage means 1
0 means that every time a new arterial pulse wave value V is extracted, the maximum value Vmax' (storage area 10
The arterial pulse wave value V and cuff pressure value P before the time when they start to exceed the provisional judgment boundary value V〓', which is obtained by multiplying the data stored in c) by a predetermined ratio α, are deleted, and unnecessary data is deleted. By erasing the data and storing only valid data in the storage means 10,
The small storage capacity of the storage means 10 is effectively utilized.

FIG. 5 is a flowchart showing the operation of one embodiment of the present invention. Now, when the information separating means 9 newly separates and extracts the arterial pulse wave value V and the cuff pressure value P, the arterial pulse wave value V and cuff pressure value P are stored in storage means 1.
At the same time, the arterial pulse wave value V is stored in the storage areas 10a and 10b sequentially left-aligned, and at the same time the arterial pulse wave value V is set to the provisional maximum value.
It is determined whether the maximum value Vmax' is larger than Vmax', and if it is larger, the provisional maximum value Vmax' stored in the storage area 10c is updated to the newly extracted arterial pulse wave value V. Next, a provisional maximum judgment boundary value V〓' is calculated by multiplying the provisional maximum value Vmax' by a predetermined ratio α, and the arterial pulse wave value V and cuff pressure value before starting to exceed this provisional maximum judgment boundary value V〓'. Delete P and move the remaining data to the left. In this case, the time when the provisional maximum judgment boundary value V〓′ starts to be exceeded is determined, for example, in order from the latest arterial pulse wave value V to the provisional maximum judgment boundary value V〓′.
V〓′ is compared with the provisional highest judgment boundary value twice or more.
When V〓′ becomes larger, the provisional highest judgment boundary value
It is determined that the time when the arterial pulse wave value V exceeding V〓′ appears is the time when the value begins to exceed V〓′. In this way, malfunctions caused by fluctuations due to noise or the like are prevented by not allowing the temporary maximum judgment boundary value V〓' to start exceeding the case where it becomes larger only once. Next, in the blood pressure determining means 13,
When the true maximum value Vmax of the arterial pulse wave value V is determined, the oldest data stored in the storage means 10 is set as the data of the systolic blood pressure period, and the cuff pressure value P is displayed as the systolic blood pressure on the display means 16. It is designed to be displayed on the display. That is, in FIG. 6b,
After the point when the arterial pulse wave value V reaches point B, it becomes the provisional maximum value.
Vmax′ is not updated, and the arterial pulse wave value V at point B
is determined to be the true maximum value Vmax, and the data at point C, which is the oldest data among the data stored in the storage means 10 (storage areas 10a,
10b) is determined to be the systolic blood pressure period, and the cuff pressure value P stored corresponding to the arterial pulse wave value V at point C is determined to be the systolic blood pressure value. Furthermore, at the time when the true maximum value Vmax of the arterial pulse wave value V is determined, the data at point A is deleted because it is the data before the arterial pulse wave value V started to exceed the maximum judgment boundary value V〓. Needless to say, there are. In this way, storage means 1
The systolic blood pressure value can be easily determined based on the oldest data stored in
The calculation time from obtaining Vmax to calculating the systolic blood pressure value can be significantly reduced, and blood pressure measurement results can now be displayed quickly.

By the way, as shown in Fig. 7 or 8, systolic blood pressure (cuff pressure value P at the time of systolic blood pressure) and mean blood pressure (cuff pressure value P at the time when the maximum value Vmax appears)
The difference between Vmax and Vmax is large, and the number of pulses required until the maximum value Vmax is determined becomes large, and the storage areas 10a and 10b of the storage means 10 may become full. Therefore, in the embodiment, a predetermined number of stored arterial pulse wave values V and cuff pressure values P (in the embodiment
10), the provisional maximum value Vmax', which is the maximum value of the previously extracted arterial pulse wave values V, and the oldest arterial pulse wave value among the stored arterial pulse wave values V.
If the second predetermined ratio γ (for example, 0.5) is exceeded, that is, Vold>γ
In the case of ×Vmax', the oldest arterial pulse wave value V and cuff pressure value P are deleted and the newly extracted arterial pulse wave value V and cuff pressure value P are stored, and the second predetermined ratio γ is not exceeded. If, i.e., Vold<γ
×Vmax′ (Vold>γ×Vmax′) When the arterial pulse wave value V exceeds the provisional maximum value Vmax′,
While only updating the above provisional maximum value Vmax′,
Arterial pulse wave value V and cuff pressure value P extracted thereafter
The storage means 10 is formed so as not to store data, thereby avoiding inconveniences due to insufficient storage capacity.

For example, in FIG. 7, when the arterial pulse wave value V reaches point B, the storage area 10 of the storage means 10
a, 10b are full, and at this time there is no arterial pulse wave value V less than the provisional maximum judgment boundary value V〓′, so
You will no longer be able to erase old data and move data to the left. In this way, storage areas 10a, 1
When 0b is full, the arterial pulse wave value V at point B
In other words, the provisional maximum value Vmax' is compared with the arterial pulse wave value V at point A, which is the oldest data, and if it increases by more than a predetermined ratio γ, then Vold<γ×
In the case of Vmax', only the provisional maximum value Vmax' is updated and the arterial pulse wave value V before it starts to exceed the provisional maximum judgment boundary value V' is deleted, and the new arterial pulse wave value V and cuff pressure are The value P is not stored. Here, the arterial pulse wave value V is the true maximum value Vmax
At the point D when the point C is reached, the data before the point C is erased, and the time when the arterial pulse wave value V at the point C, which is the oldest data stored in the storage means 10, appears is determined to be the systolic blood pressure time. The cuff pressure value P corresponding to this arterial pulse wave value V is displayed on the display means 16 as the systolic blood pressure value.

On the other hand, in the case of FIG. 8, when the point C' is reached, the storage areas 10a and 10b of the storage means 10 are full, and the arterial pulse wave values V at the points C' and D' are compared and a predetermined value is determined. Has not increased by more than the ratio γ (Vold>γ
×Vmax'), erase the data at point D', move the remaining data to the left, and newly store the arterial pulse wave value V and cuff pressure value P at point E in the storage areas 10a and 10.
Store it at the right end of b. After repeating the above operation, when the arterial pulse wave value V at point B' appears,
A comparison of the arterial pulse wave value V between point B' and point A' is performed,
Since this ratio has reached the predetermined ratio γ, subsequent data is not stored, and only the provisional maximum value Vmax' is updated and the arterial pulse wave value V before it begins to exceed the provisional maximum judgment boundary value V〓' is deleted. and finally storage means 1
The appearance time of the oldest data stored in 0 is determined to be the systolic blood pressure time, and the cuff pressure value P of that data is determined.
is displayed on the display means 16 as the systolic blood pressure value.

(Embodiment 2) FIG. 9 is a flowchart showing the operation of another embodiment, in which when the true maximum value Vmax of the arterial pulse wave value V is determined, the arterial pulse wave stored in the storage means 10 is A predetermined ratio α to the true maximum value Vmax of the value V
The blood pressure determining means 13 is configured to determine the cuff pressure value P corresponding to the arterial pulse wave value V which begins to exceed the maximum determination boundary value V obtained by multiplying is exactly the same as Example 1.

Now, in the case of FIG. 7, until the arterial pulse wave value V at point D is obtained and the true maximum value Vmax is determined, the storage means 10 stores data from point A to point D, as in the first embodiment. is memorized and the true maximum value
After Vmax is determined, from the memorized point A to D
The arterial pulse wave value V at the point and the highest judgment boundary value V〓 are sequentially compared, and the point C, which is the time when the arterial pulse wave value V starts to exceed the highest judgment boundary value V〓, is determined to be the systolic blood pressure period. There is.

On the other hand, in the case of Fig. 8, when the arterial pulse wave value V at point B' appears, the data from A' to B' is stored in the storage area 10 until the true maximum value Vmax is obtained.
a, 10b, and when the true maximum value Vmax is determined at point F', the systolic blood pressure timing is determined at point B'.

[Effects of the Invention] As described above, the present invention includes a cuff that is attached to the main part of a person to be measured, a pressurizing means that increases the pressure inside the cuff, and an exhaust system that gradually lowers the pressure inside the cuff. means, a pressure sensor that converts the pressure within the cuff into an electrical signal, and a pressure information separation means that extracts an arterial pulse wave value and a cuff pressure value from the pressure sensor output;
Storage means for storing arterial pulse wave values and cuff pressure values extracted by the pressure information separation means, and blood pressure determination for determining systolic and diastolic blood pressure values by appropriately reading and comparing the pressure values stored in the storage means. and a display means for displaying both determined blood pressure values, and the time when the arterial pulse wave value first begins to exceed the judgment boundary value obtained by multiplying the maximum value of the arterial pulse wave value by a predetermined ratio is defined as the systolic blood pressure period. In an electronic blood pressure monitor, the systolic blood pressure determining means of the blood pressure determining means is configured to determine the cuff pressure value at that time as the systolic blood pressure value,
Every time a new arterial pulse wave value is extracted, the arterial pulse before the time when it begins to exceed the provisional judgment boundary value obtained by multiplying the provisional maximum value, which is the maximum value of the already stored arterial pulse wave values, by a predetermined ratio. The storage means is configured to erase wave values and cuff pressure values, and unnecessary data is sequentially erased and only valid data is stored in the storage means, so that the memory of the storage means is It is possible to provide a small and low-cost electronic blood pressure monitor with a reduced capacity,
Furthermore, since the amount of data used for blood pressure determination is reduced, blood pressure determination calculations can be simplified and blood pressure measurement results can be displayed quickly.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of the present invention, FIG. 2 is a block diagram of the same as the above, FIG. 3 is a main block circuit diagram of the same as the above, FIGS. 4 to 7 are explanatory diagrams of the same as the above,
FIG. 8 is an explanatory diagram of the operation of another embodiment, and FIG. 9 is an explanatory diagram of the operation of still another embodiment. 2 is a cuff, 5 is a pressure sensor, 9 is an information separation means, 10 is a storage means, 13 is a blood pressure determination means, 16
is a display means.

Claims (1)

[Claims] 1. A cuff that is attached to the main part of a person to be measured to prevent blood flow;
A pressurizing means for increasing the pressure within the cuff, an evacuation means for gradually decreasing the pressure within the cuff, a pressure sensor for converting the pressure within the cuff into an electrical signal, and an arterial pulse wave value and cuff pressure determined from the pressure sensor output. A pressure information separation means for extracting values, a storage means for storing arterial pulse wave values and cuff pressure values extracted by the pressure information separation means, and pressure values stored in the storage means are read out as appropriate and are compared and calculated. The arterial pulse wave value is a determination boundary value obtained by multiplying the maximum arterial pulse wave value by a predetermined ratio. In an electronic sphygmomanometer, the systolic blood pressure determining means of the blood pressure determining means is configured to determine the time when the cuff pressure first begins to exceed the systolic blood pressure as the systolic blood pressure. Each time arterial pulse wave values and cuff pressure values are extracted, the arterial pulse wave value and cuff pressure value before the time when the temporary judgment boundary value, which is obtained by multiplying the provisional maximum value which is the maximum value of the already stored arterial pulse wave values by a predetermined ratio, begins to be exceeded are extracted. An electronic blood pressure monitor characterized in that a memory means is formed to erase the information. 2. When the number of stored arterial pulse wave values and cuff pressure values exceeds a predetermined number, the provisional maximum value Vmax', which is the maximum value of the previously extracted arterial pulse wave values, and the stored arterial pulse wave values are The oldest arterial pulse wave value
Vold is compared with the second predetermined ratio as γ, and if Vold>γ×Vmax′, the oldest arterial pulse wave value and cuff pressure value are deleted and the newly extracted arterial pulse wave value and cuff pressure are If Vold<γ×Vmax′, and the next extracted arterial pulse wave value exceeds the provisional maximum value, only the provisional maximum value is updated, and the arterial pulse wave value extracted thereafter is 2. The electronic sphygmomanometer according to claim 1, wherein the storage means is formed so as not to store pulse wave values and cuff pressure values. 3. If the second predetermined ratio is not exceeded, the storage means is configured to erase the arterial pulse wave value and cuff pressure value before they start to exceed the provisional judgment boundary value obtained by multiplying the provisional maximum value by the predetermined ratio. The blood pressure determining means is configured to determine, when the true maximum value of the arterial pulse wave value is determined, the cuff pressure value corresponding to the oldest arterial pulse wave value stored in the storage means as the systolic blood pressure value. An electronic blood pressure monitor according to claim 2, characterized in that: 4 When the true maximum value of the arterial pulse wave value is determined,
Among the arterial pulse wave values stored in the storage means, the cuff pressure value corresponding to the arterial pulse wave value that begins to exceed the determination boundary value obtained by multiplying the true maximum value of the arterial pulse wave value by a predetermined ratio is determined as the systolic blood pressure value. The electronic blood pressure monitor according to claim 2, characterized in that the blood pressure determination means is formed to determine that.