JPH082349B2 - Electronic blood pressure monitor - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electronic sphygmomanometer.

2. Description of the Related Art The configuration of a conventional electronic sphygmomanometer is shown in FIG. 5, and the measurement principle will be described. First, the armband 29 is attached to the upper arm of the human body. At that time, the microphone 30 built in the armband 29 is aligned with the position of the artery of the upper arm of the human body. Next, a rubber ball 31 is used to send air into the arm band through the rubber tube 32 to apply pressure. When the air supply by the rubber ball 31 is stopped, it is slightly discharged from the minute discharge valve built in the rubber ball 31, and the pressure in the arm band gradually decreases. The pressure inside the arm band 29 is
Detected by pressure sensor 33 connected to 32, pressure sensor 33
The output of is converted into a digital signal by the A / D converter 34, and the CPU35
Will be input. Also, when the pressure in the armband 29 is high, the artery of the brachia is compressed and ischemic, so the output of the microphone 30 on the artery has a low frequency. When the sound is generated and the pressure further decreases, the Korotkoff sound disappears. Therefore, the output voltage of the microphone 30 is amplified by the amplifier circuit 37, and the output voltage of the amplifier circuit 37 is input to the filter circuit 38 to detect the Korotkoff sound. The output of the filter circuit 38 is compared by the comparator 39 to be the input of the CPU 35, and in the CPU 35, the output of the A / D converter 34 when the output of the comparator 39 first becomes high is set as the systolic blood pressure, and finally. The output of the A / D converter 34 when high is detected is displayed on the display 36 as the minimum blood pressure.

Problems to be Solved by the Invention Such a conventional electronic sphygmomanometer is inconvenient because the microphone and the artery need to be aligned when the armband is worn. Also, since the microphone detects Korotkoff sounds, it sometimes malfunctions due to electrical noise or noise.

Therefore, an object of the present invention is to provide a sphygmomanometer that can easily measure blood pressure without a microphone and that is low in cost.

Means for Solving the Problems In order to solve the above problems, the present invention provides an arm girdle attached to the upper arm of a human body and a pressurizing means for supplying air to the arm girth to pressurize the upper arm of the human body until the blood is blocked. A minute discharge means for gradually discharging slightly, a pressure detecting means for detecting the pressure in the arm band at a constant sampling period, a converting means for converting the output of the pressure detecting means into a digital pressure signal, and a minute discharge. First detecting means for detecting the starting point of the pressure vibration generated in synchronization with the pulse, and second detecting means for detecting the end point of the pressure vibration,
First calculating means for calculating the instantaneous value of the pressure vibration, and the maximum value of the instantaneous value of the pressure vibration as the magnitude of the pressure vibration generated during the minute discharge in the range from the starting point to the end point of the pressure vibration. Third detecting means for detecting, storage means for storing the magnitude of the pressure vibration and the pressure at the starting point of the pressure oscillation, and determining means for determining a blood pressure value from the magnitude of the pressure oscillation and the pressure at the starting point of the pressure oscillation. And a display unit for displaying the blood pressure value.

Action The present invention has the above-described configuration and is microphoneless,
The position adjustment is unnecessary and the cost is reduced.
In addition, the loudness of the blood vessel sound is easily detected as a vibration component of the pressure, and the change amount with respect to the pressure drop line during the minute discharge is detected as the vibration component of the pressure in order to eliminate the influence of the change in the exhaust velocity. , An accurate blood pressure value can be obtained regardless of the exhaust speed.

Example Hereinafter, an example of the present invention will be described in detail with reference to FIGS. 1 to 4. First, the armband 1 is attached to the upper arm of the human body. At this time, unlike the conventional example, since there is no microphone, alignment with the artery is unnecessary. Next, the rubber ball 2 is fed into the arm band through the rubber tube 3 to pressurize it to a pressure higher than the systolic blood pressure. This period is called a pressurizing mode. Next, the rubber ball 2 is slightly discharged through a minute discharge valve built in, and the pressure is gradually reduced. The pressure in the armband 1 is detected by the pressure sensor 4 connected to the rubber tube 3, and the output of the pressure sensor 4 is converted into a digital pressure signal by the A / D converter 5 and becomes the input of the CPU 6. Further, unlike the A / D converter 34 that detects only the pressure value in the armband of the conventional example, the A / D converter 5 also detects a minute change in pressure due to blood vessel sound at the same time, so the resolution is higher than 1/10 mmHg. Use one.

Next, a method of processing the detected digital pressure signal in the CPU 6 will be described with reference to FIGS. The time until the measurement is completed is called the measurement mode, and the time until the exhaust is completed is called the exhaust mode (FIG. 3). In the measurement mode, data acquisition is first started (step 8). The pressure p1 immediately after the start of measurement is taken in (step 9) and stored as initial data (step 10). The pressure p2 at the next sampling is taken in (step 11) and stored (step 12). Next, initialization is performed (step 13), i is incremented (step 14), and pressure measurement after the next sampling time is performed (step 15). Next, the vibration amount qi of the pressure is obtained by the calculation of the equation (1) (step 16).

qi = pi- {pn- (pn-1-pn) (i-Tn) / (Tn-Tn-
1)} (1) Here, i indicates the i-th sampling after the start of measurement, pi is the instantaneous value of the current pressure, Pn and Tn are the pressure at the starting point of the vibration at the beat and n beats. Indicates the value of i at the starting point of the eye (3rd,
(See Figure 4). Immediately after the start of measurement, Pn-1 and Tn-1 are the data immediately after the start of measurement, and Pn and Tn are the second data. Two
After the beat, Pn−1 and Tn−1 are the data of the starting point of the pressure vibration one beat before, and Pn and Tn are the starting points of the pressure vibration of the current beat.

Next, the maximum value of qi is stored (steps 17 and 18).
Next, the starting point of the pressure vibration is detected (steps 19 and 21). When the time lapse from the starting point of the pressure oscillation is less than Ts, it is compared with the extension line of the starting point of the previous beat and this beat, and when the time lapse is Ts or more, the extension line is (i-Tn-Ts) r1. In any case, when the vibration component qi of the pressure is larger than the straight line obtained by adding, the process returns to step 14 and the processes up to step 21 are repeated. When it becomes the following, it is considered that the falling point of the pressure vibration is detected, the detection of the maximum value of the current pressure vibration is completed, and it is judged whether or not the magnitude Qn of the current pressure vibration is larger than a certain judgment level r2 (step 22 ), If it is not large, the vibration value of the current pressure is canceled and the current instantaneous value is stored as a new starting point of the pressure (step 23), and the process returns to step 14 and the processing up to step 23 is repeated. As described above, the magnitude Qn of pressure oscillation and the pressure Pn at the rising point at that time are detected as shown in FIG.

Next, determine whether Qn has reached the maximum value (step 2
4) If not reached, n is incremented (step 25), the current instantaneous value is stored as a new rising point of pressure (step 26), and steps 14-26 are performed until the maximum value of Qn is determined. repeat. When the maximum value of Qn is determined (Qmax), the pressure value Pn at the first Qn that is the detection level determined by k1Qmax is the maximum blood pressure, and the pressure Pn at the first Qn when it is less than k2Qmax is the minimum blood pressure. (Step 27). If the conditions are not met and the blood pressure cannot be determined, repeat steps 14-27. The determined blood pressure value is displayed on the display 7 (step 28).

EFFECTS OF THE INVENTION As described above, according to the present invention, the microphone is not required and the positioning of the microphone is not required. Further, a microphone, an amplifier circuit, a filter circuit, and a comparator are unnecessary, and the cost is reduced.

Further, since the loudness of the blood vessel sound can be easily detected as a vibration component of the pressure value and can be detected without being affected by the exhaust speed by the correction, it is possible to provide an electronic sphygmomanometer that can accurately detect blood pressure.

[Brief description of drawings]

FIG. 1 is a block diagram of an electronic sphygmomanometer according to an embodiment of the invention,
FIG. 2 is a flow chart of the blood pressure detecting method of the same embodiment, FIGS. 3 and 4 are explanatory views of a method of detecting the vibration component of the pressure of the same embodiment, and FIG. 5 is a configuration of a conventional electronic blood pressure monitor. It is a figure. 1 ... arm band, 2 ... rubber ball, 3 ... rubber tube, 4 ... pressure sensor, 5 ... A / D converter, 6 ... CPU, 7 ... display.

Claims (1)

[Claims] 1. An arm band worn on the upper arm of a human body, a pressurizing means for supplying air to the arm band to pressurize the upper arm of the human body until ischemia, a minute draining means for slightly discharging the arm, and the arm. The pressure detecting means for detecting the pressure in the band at a constant sampling period, the converting means for converting the output of the pressure detecting means into a digital pressure signal, and the pressure oscillation at the first beat after the start of blood pressure measurement, the previous point of sampling. When the digital pressure signal of this time is larger than the value of the extension line of the pressure drop line formed by connecting the two points before and after, the starting point of the pressure vibration of the previous beat and the previous point of sampling for the second and subsequent beats. When the digital pressure signal of this time is larger than the value of the extension line of the pressure drop straight line formed by connecting, the previous point of sampling is detected as the starting point of the pressure oscillation that occurs in synchronization with the pulse during minute discharge. With detection means For a predetermined time after the detection of the starting point of this time, when the current pressure becomes smaller than the value of the extension line of the pressure drop straight line connecting the starting point of the previous pressure vibration and the starting point of this pressure vibration, It is detected as the end point of the vibration, and after the predetermined time has elapsed, the value obtained by adding the value obtained by multiplying the time from the time when the predetermined time has elapsed to the current time by a predetermined value to the value of the extension line of the pressure drop line is the current pressure. Of the pressure drop line formed by connecting the second detecting means for detecting the present time as the end point of the pressure vibration when the value of becomes smaller and the starting point of the pressure vibration of the previous beat and the starting point of the pressure vibration of the present beat. First calculation means for obtaining a value obtained by subtracting the value of the extension line from the current pressure value as the instantaneous value of the pressure vibration, and the maximum value of the instantaneous value of the pressure vibration, which is the magnitude of the pressure vibration generated during the minute discharge. Before the pressure oscillation Third detection means for detecting in the range from the starting point to the end point, a storage means for storing the magnitude of the pressure vibration and the pressure at the starting point of the pressure oscillation, the magnitude of the pressure oscillation and the pressure at the starting point of the pressure oscillation. An electronic sphygmomanometer including a determining means for determining a blood pressure value from the display means and a display means for displaying the blood pressure value.