JPS63230146A - Blood pressure measuring method - 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] [Industrial Application Field] The present invention comprises 1. This invention relates to a method for measuring blood pressure (systolic blood pressure, diastolic blood pressure, mean blood pressure) using oscillation phenomenon (vibration phenomenon that occurs in cuff internal pressure with arterial pulsation).

[Prior art]

Riva-R as a non-invasive method of measuring blood pressure
The occ f method (auscultation method) is known. This method is
A cuff is wrapped around the subject's upper arm, and Korotkoff sounds are listened to with a stethoscope in an artery distal to the cuff wrapping area (e.g. radial artery). The internal pressure is the systolic blood pressure.

This is a method to achieve the lowest blood pressure. Microphone-type automatic blood pressure monitors based on this method are known as general blood pressure monitors, but with this blood pressure needle, the point at which Korotkoff sounds cannot be heard is defined as the 5th Swan point or the 4th Swan point. Therefore, there was a problem that a difference in lQmmHg appeared in the measured minimum blood pressure value, making it impossible to accurately measure the minimum blood pressure.
Journal 103: 879 198
2).

Additionally, depending on the subject's physical condition (low blood pressure, shock), it may be difficult to hear Korotkoff sounds.
In such cases, there was a problem in that blood pressure could not be measured.

Therefore, in recent years, instead of the Rjva-Rocci method, a method of measuring blood pressure using an oscillation phenomenon (oscillometric measurement method) has been developed. The principle of this method will be briefly explained below.

When the cuff is wrapped around the upper arm and the internal pressure of the cuff is increased until it exceeds the systolic pressure, and then the pressure is gradually reduced, a plurality of regularly occurring vibrations occur in the internal cuff pressure in synchronization with the arterial pulsation. And the maximum amplitude of each vibration is very small at first, then gradually its maximum amplitude increases, and then it reaches its maximum value.

It also gradually becomes smaller. During these changes, there are times when the maximum amplitude rapidly increases and times when the maximum amplitude rapidly decreases, and the intracuff pressure at the time when the maximum amplitude of vibration suddenly increases is equal to the systolic pressure (systolic pressure). ) to,
The intracuff pressure at the point of sudden decrease is the diastolic pressure (diastolic pressure)
The intracuff pressure at the time when the maximum width of one tassel reaches its maximum value corresponds to the average blood pressure. Therefore, vibrations based on this arterial pulsation are detected, the obtained vibrations are analyzed, and the three
The time point was detected and the systolic blood pressure, diastolic blood pressure, and mean blood pressure were determined (Medical Instrumentation Vol. 1.53. No. 11.1)
983).

[Problem that the invention seeks to solve]

However, this oscillometric measurement method has the problem that it is difficult to specify the point at which the maximum amplitude suddenly increases or decreases as described above, and it is difficult to accurately measure blood pressure.

The present invention has been made in view of the above circumstances, and involves detecting a plurality of standard patterns of vibrations in advance, and then comparing the standard patterns with a plurality of measurement patterns of vibrations detected from the subject. It is an object of the present invention to provide a blood pressure measuring method that can easily and accurately calculate systolic blood pressure and diastolic blood pressure.

[Means for solving problems]

The blood pressure measurement method according to the present invention detects a plurality of vibrations generated in the cuff internal pressure due to arterial pulsation from the subject while lowering the cuff internal pressure, and detects the systolic blood pressure and diastolic blood pressure of the subject. In a blood pressure measurement method that measures cuff pressure, the rate of change in the maximum amplitude of two adjacent vibrations, the chronological position of each vibration, and the systolic blood pressure and diastolic blood pressure are shown for a preset standard pattern of vibrations in the cuff internal pressure. The chronological position of the time point is memorized, and the measurement pattern of multiple vibrations generated in the cuff internal pressure from the subject is detected in order to measure the blood pressure, and the maximum amplitude of two adjacent vibrations in the measurement pattern is detected. The rate of change in the measured pattern is calculated, and the time-series position of each vibration in the measurement pattern is determined, and this measurement pattern and the standard pattern are compared in time-series, and the rate of change calculated in the measurement pattern and the change in the standard pattern are calculated. The feature is that the systolic blood pressure and diastolic blood pressure are calculated by comparing the blood pressure and the blood pressure.

[Effect]

First, a standard pattern of vibrations is set in advance, and for that standard pattern, the rate of change in maximum amplitude in two adjacent fil vibrations, the time-series position of each vibration, and the systolic blood pressure (
The chronological position of the point in time when the diastolic blood pressure (diastolic blood pressure) is indicated is memorized. Next, a vibration measurement pattern of the subject whose blood pressure is to be measured is detected. In the measurement pattern detected from the subject, the rate of change in the maximum amplitude of two adjacent vibrations is calculated, and the time-series position of each vibration is determined. Next, this measurement pattern is compared with a standard pattern stored in advance in time series, and the rate of change in the maximum amplitude of both patterns is compared to calculate the systolic blood pressure and the diastolic blood pressure.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on drawings showing embodiments thereof. FIG. 1 is a block diagram of an apparatus for carrying out the method of the present invention, in which 1 is a vibration attached to a cuff 2 that detects over time a plurality of vibrations (measurement patterns) generated in the cuff internal pressure. Sensor 3 is an internal pressure sensor that is attached to a pressure pump (not shown) for increasing and decreasing the internal pressure of the cuff, and outputs the internal pressure of the cuff by 1★. Maximum amplitude detector 4
inputs the vibration signal detected by the vibration sensor 1, detects the maximum amplitude of each vibration using a peak hold circuit, performs A/D (analog-digital) conversion, and sends the digital signal of the maximum amplitude to the CPt15. Output. Further, the pressure signal processor 6 inputs the analog pressure signal detected by the internal pressure sensor 3, performs A/D conversion, and outputs a digital signal of the cuff internal pressure to the CPU 5. The maximum amplitude detector 4 detects the time when the maximum amplitude signal is input using a differentiating circuit, performs peak hold at this timing, and outputs a strobe signal indicating this time to the CPU 5. C
The PU 5 is configured to read the cuff internal pressure signal from the pressure signal processor 6 in synchronization with that time.

Each time each vibration is detected, the CPU 5 obtains data indicating the maximum amplitude of the vibration, time data (time series position) at the time of the maximum amplitude, and data on the cuff internal pressure at that time,
Write these data of the measurement pattern to RAM 7,
RAM 7 stores these data. Note that the time data may be any data that indicates the time-series position of each vibration.
It goes without saying that the data indicates the time at which each vibration occurs, but may also be, for example, a time series number based on the first vibration. Next, the CPU 5 calculates the blood pressure based on these data and data previously stored in the ROM 8, which will be described later.

1? The OM 8 stores preset standard patterns for each vibration in the cuff internal pressure. More specifically, the rate of change (increase rate or decrease rate) in the maximum amplitude of two adjacent vibrations, the time-series position of each vibration, and the time-series position of vibrations when indicating systolic blood pressure and diastolic blood pressure are remembered. The rate of change in the maximum amplitude of adjacent vibrations is defined by the following equation (1).

The maximum amplitude of the previous vibration However, this rate of change is the increase rate if the maximum amplitude of the current vibration ≧ the maximum amplitude of the previous vibration, and the decrease rate if the maximum amplitude of the current vibration is less than the maximum amplitude of the previous vibration. show.

Next, a specific measurement method will be explained. First, wrap the cuff around the subject's upper arm, and first lower the cuff internal pressure by 3 points below the systolic pressure.
Set it to about 0+nHg higher, then 20t higher than the diastolic pressure.
ml (g). During this time, the vibration sensor 1 detects vibrations occurring in the cuff internal pressure, the internal pressure sensor 3 detects the cuff internal pressure, and R
The maximum amplitude of each vibration, the chronological position of each vibration, and the internal cuff pressure at that time are stored in AM7. Figure 2 shows RAM
7 schematically shows the data contents stored in FIG. 7, in which the maximum amplitude of each vibration and the cuff internal pressure at that time are stored in chronological order. In the figure, the ○ numbers indicate data numbers assigned according to the detection order, with the first detected vibration being ▪, and the time-series position of each vibration is specified by this data number. Next, the CPU 5 calculates the systolic blood pressure, the diastolic blood pressure, and the mean blood pressure based on these data of the measurement pattern stored in the RAM 7 and the data of the standard pattern stored in the ROM B in advance.

Below, the steps for calculating these blood pressures in the CPU 5 are as follows.
This will be explained based on FIG. 3 which shows the flowchart. C
PIJ5 is detected from RAM 7 in the order (Fig. 2 ■,
(2) The data of the maximum amplitude of two adjacent vibrations are read out in sequence according to the order of (1), and the increase rate of the maximum amplitude is calculated as described above (the peak calculated based on equation 11). If the calculated increase rate is equal to or higher than the lower floor value α (α is the allowable lower limit value of the increase rate of the maximum amplitude of vibration when indicating systolic blood pressure) (C1 has 170
The rate of change of the standard pattern at the point in time corresponding to this vibration is taken from M8, the deviation between these two is determined, and the absolute value of the deviation is the lower floor value β (β is the standard for determining systolic blood pressure). The absolute value of the deviation of the maximum amplitude from the pattern is within the permissible upper limit (d), and the deviation between the time series position of this vibration and the time series position indicating the systolic blood pressure of the standard pattern is calculated, and the absolute value of the deviation is When the value is within the upper limit γ (γ is the allowable upper limit of the absolute value of the deviation of the time-series position from the standard pattern for determining systolic blood pressure), the cuff internal pressure at this time is determined as the systolic blood pressure. (fl.

On the other hand, if any of the above three conditions is violated, the maximum amplitudes of the next two vibrations are read again, and the same operation is repeated until the systolic blood pressure is calculated.

After memorizing the systolic blood pressure, read out the maximum amplitude of each vibration again fgl, check whether it shows the maximum value (hl, if it shows the maximum value, store the cuff internal pressure at that time as the average blood pressure in RAM 7) (1) On the other hand, if the maximum value is not shown, the maximum amplitude - of the next vibration is read again, and the same operation is repeated until the average blood pressure is calculated.

Next, the maximum amplitude data of two adjacent vibrations is read out (j), and the rate of decrease in the maximum amplitude is calculated based on the equation (1) (k). If the calculated rate of decrease is greater than or equal to the lower limit value α (1), the rate of change of the standard pattern at the point in time corresponding to this vibration is read from the ROM 8, and this two
The absolute value of the deviation is within the upper limit β ((2), and the deviation between the time-series position of this vibration and the time-series position showing the standard pattern of diastolic blood pressure is determined, and the absolute value of the deviation is within the upper limit β ((2)). When the absolute value is within the upper limit value 1 (fn), the cuff internal pressure at this time is taken as the diastolic blood pressure and I? AM Stored at 7 (0). On the other hand, if any of the above three conditions is violated, read out the maximum amplitude of the next two vibrations,
The same operation is repeated until the diastolic blood pressure is detected.

The operation ends when the diastolic blood pressure is stored in the RAM 7, the systolic blood pressure, the diastolic blood pressure and the mean blood pressure are calculated, and the RA
Stored in M7.

The point in time when the systolic blood pressure (diastolic blood pressure) is indicated corresponds to the point in time when the maximum amplitude of vibration rapidly increases (decreases) in the oscillation phenomenon. At the point in time when the systolic blood pressure (diastolic blood pressure) specified by the present invention is indicated, the rate of increase (decrease) in the maximum amplitude at this point is greater than or equal to the lower limit value α, and the rate of increase (decrease) in the maximum amplitude at this point The absolute value of the deviation between the rate of change of the standard pattern at the time corresponding to the time series and the time series position is within the upper limit β, and the time series position and the time series position of the time series indicate the systolic blood pressure (diastolic blood pressure) of the standard pattern. Since the absolute value of the deviation from this is within the upper limit value 1, the cuff internal pressure at this specified time point can be calculated as the systolic blood pressure (diastolic blood pressure).

In addition, in this example, the lower limit value was set to be the same in order to calculate the systolic blood pressure and diastolic blood pressure, but in the case of calculating the systolic blood pressure and the case of calculating the diastolic blood pressure,
Of course, different lower limit values may be set.

In addition, although it was decided to store a general standard pattern in advance in ROM 8, vibrations are detected in advance from the subject whose blood pressure is to be measured and the detected pattern is used as the standard pattern. The blood pressure may be calculated by comparing the measurement pattern detected from the same subject. In such a case, 1. Since the standard pattern is detected from the subject himself/herself, blood pressure can be calculated more accurately.

〔effect〕

As detailed above, in the method of the present invention, blood pressure (systolic blood pressure, diastolic blood pressure) is calculated by comparing a preset standard pattern of vibrations with a measurement pattern of actually detected vibrations. It is possible to easily and accurately measure blood pressure without requiring complicated analysis to identify the two points in time when the maximum amplitude of vibrations suddenly increases or decreases.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an apparatus for carrying out the method of the present invention, FIG. 2 is a schematic diagram schematically showing the storage contents of a RAM, and FIG. 3 is a flowchart showing the operating procedure of CP[I.

Claims (1)

[Claims] 1. While lowering the cuff internal pressure, a plurality of vibrations generated in the cuff internal pressure due to arterial pulsations are detected from the subject, and the systolic blood pressure and diastolic blood pressure of the subject are determined. In the blood pressure measurement method to be measured, for a preset standard pattern of vibrations in the cuff internal pressure, the rate of change in the maximum amplitude of two adjacent vibrations, the chronological position of each vibration, and the time at which the systolic blood pressure and diastolic blood pressure are indicated. The serial position is memorized, and the measurement pattern of multiple vibrations generated in the cuff internal pressure from the subject is detected in order to measure blood pressure, and the rate of change in the maximum amplitude of two adjacent vibrations in the measurement pattern is calculated. Also, calculate the time series position of each vibration of the measurement pattern, compare this measurement pattern with the standard pattern in time series, and compare the rate of change calculated in the measurement pattern and the rate of change in the standard pattern. A blood pressure measurement method characterized by calculating systolic blood pressure and diastolic blood pressure by comparing them.