JPH06114B2 - Electronic blood pressure monitor pressure correction device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pressure correction device for an electronic sphygmomanometer.

Conventional technology Generally, the operation and operation procedure of an electronic blood pressure monitor is turned on →
Pressurization → Measurement → Exhaust → Pressurization → Measurement → Exhaust (Repeat thereafter)
Becomes Generally, a sphygmomanometer sends air to a hemostatic rubber bag inside the armband, detects the pressure with a pressure sensor connected to the hemostatic rubber bag with a rubber tube, and calculates the output of the pressure sensor with a micro-processor. Seeking blood pressure. That is,
The output of the pressure sensor in the state where the pressure inside the hemostatic rubber bag is open to the atmosphere is used as a correction value, and the blood pressure is obtained by subtracting the correction value from the output of the pressure sensor when the pressure is applied.

A conventional flow chart for blood pressure measurement is shown in FIG. After the power is turned on (step 51), the output of the pressure sensor is first fetched (step 52), and the values are stored as the measured value P ₁ and the correction value P ₀ (step 53). After that, the timer T ₁ for determining the pressure sampling period is started (step 54), and the blood pressure measurement process (step 61) is performed until the timer T ₁ times up. The blood pressure measurement process is a process of determining and displaying the maximum and minimum blood pressure and a process related thereto. When the tire T ₁ has timed up, the timer T ₁ is restarted (step 56), the pressure is measured (step 57), and the value is stored as P ₁ (step 5).
8). The current pressure P is obtained from the difference between P ₁ and P ₀ (step 59). Next, it is determined whether P is positive or negative (step 6
0), positive or zero, blood pressure measurement process (step 61)
If it is negative, P ₁ is stored in P ₀ as a new correction value (step 62). Then, the process returns to step 55.

In this method, when there is a residual pressure when the power is turned on, the residual pressure is used as the correction value P ₀ immediately after the power is turned on. Since the pressure drop thereafter is as shown in FIG. 6, when a negative pressure is detected by detecting the pressure at each pressure sampling cycle, the correction value P ₀ is immediately updated.

The problem to be solved by the invention However, as another case where negative pressure is generated, there is a case where the arm is bent to force sudden discharge during sudden exhaust, and the pressure drop characteristic at that time is as shown in Fig. 7. Become. In such a case, the conventional sphygmomanometer uses -ΔP as a correction value, so that an error of ΔP occurs in the pressure detected by the sphygmomanometer.

The present invention has been made in view of the above points, and an object thereof is to provide a sphygmomanometer that does not erroneously correct negative pressure as a correction value.

Means for Solving the Problems In order to solve the above problems, the present invention has a storage means for storing a pressure sensor output at power-on as a correction value and a predetermined value obtained by subtracting the correction value from the pressure sensor output. Pressure detecting means for detecting the pressure for each sampling cycle, first determining means for judging that the pressure becomes negative, time measuring means for measuring a predetermined time after the pressure becomes negative, and each sampling cycle Second determining means for determining that the pressure has increased.

Operation The present invention is configured as described above, and if the pressure does not increase within a predetermined time from the time when the negative pressure occurs, the latest pressure sensor output is set as a new correction value, and if not, the correction value. Will not be updated.

Examples Examples of the present invention will be described below.

In FIG. 1, 1 is a pressure sensor, 2 is a storage means for storing the output of the pressure sensor 1 when the power is turned on as a correction value, 3
Is a pressure detection means for subtracting the correction value from the output of the pressure sensor 1 at the time of pressure measurement to detect the pressure in each predetermined sampling cycle, and 4 is that the pressure in the sampling cycle by the pressure detection means 3 becomes negative. A first determining means for determining
Reference numeral 5 is a time measuring means for measuring a predetermined time after the pressure detected by the pressure detecting means 3 becomes negative at each sampling cycle, and 6 is a second judging means for judging that the pressure at each sampling has increased. In the second determining means 6, when the pressure does not increase within a predetermined time after the pressure in each sampling cycle becomes negative, the output of the pressure sensor 1 at the time when the predetermined time has elapsed is used as a new correction value. .

Next, the operation of the above configuration will be described with reference to FIG.

First, after turning on the power (step 13), the output of the pressure sensor 1 is fetched (step 14), and the value is measured value P ₁
Then, the correction value P ₀ and the correction value temporary save destination P ₀ ′ are stored (step 15). Next, the flags F and FF are reset (step 16). FF is a flag which is set to 0 when the pressure detection value is positive or 0, and is set to 1 when the pressure detection value is negative, and F is a time t ₂ from when the pressure detection value becomes negative to when it becomes positive.
It is a flag that is set to 0 in the following case and set to 1 if it is larger than t ₂ .

Start timer T ₁ to determine the sampling period t ₁ of the pressure value in step 17, until the timer T ₁ is the time is up performing the blood pressure measurement process (step 28). When the timer T ₁ has timed up, the timer T ₁ is restarted again (step 19) and pressure measurement is performed (step 2).
0) and store that value in P ₁ (step 21). Next, the current pressure P is obtained from the difference between P ₁ and P ₀ (step 22).

Next, it is judged whether P is positive or negative (step 23), and if it is negative, it is judged at step 29 that FF = 0, that is, the pressure P was positive or 0 at the time of the previous pressure sampling and became negative this time. Stores the latest correction value as a temporary P ₀ '(step 30), sets the flag FF to 1 (step 31), and clears and restarts the timer T ₂ for measuring the time t ₂ (step 32). . The timer T ₂ sets the observation time t ₂ of pressure transition for determining whether the negative pressure is due to natural exhaust or forced exhaust. Next, the current measured value P _{1 is changed} to a new correction value P 1.
₀ (step 33), it is determined whether the timer T ₂ is timed up (step 34), F = 1 (step 35) when the time is up, and F = 0 (step 36) when the time is not up. And Then, the process returns to step 18.

On the other hand, if it is determined in step 23 that the pressure P is positive or 0, FF = 0 is set (step 24). Next, at step 25, it is judged if F = 0, that is, if the timer T ₂ has timed up. If the time is not up, that is, as shown in FIG. 4, when the negative pressure is reached and the pressure increases within a predetermined time t ₂ , it is determined that the cause of the negative pressure is forced rapid exhaust, and the correction is performed. P ₀ is returned to the correction value P ₀ ′ immediately before the negative pressure is generated (step 26). Then, F = 1 is set (step 27), and the blood pressure measurement process (step 28) is performed.
On the other hand, if F = 1 in step 25, that is, if the pressure becomes negative as shown in FIG. 3 and the pressure simply decreases for the predetermined time t ₂ , it is determined that the cause of the negative pressure is natural exhaust, and the process proceeds to step 28. Move to blood pressure measurement. And step 18
Return to.

As described above, when the pressure value P becomes negative pressure, a change in the pressure is observed for a predetermined time t ₂ after the negative pressure is reached, and in the case of simple decrease, the correction value P ₀ is sequentially updated. Then go,
If an increase in pressure is observed, it is determined that the cause of the negative pressure is due to forced exhaust, and the correction value P ₀ is returned to the value P ₀ ′ immediately before the negative pressure. Therefore, if the pressure does not increase for a predetermined time from the time when the negative pressure is reached, the pressure sensor output after the predetermined time is set as a new correction value, and if not, the correction value is not updated.

EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to prevent post-recognition of the correction value due to the negative pressure that occurs when the arm is bent at the time of evacuation, for example, when the gas is forcibly and rapidly exhausted, and the pressure detection value of the blood pressure monitor It is possible to prevent a positive error from being added to.

[Brief description of drawings]

FIG. 1 is a block diagram of a pressure correction device for an electronic sphygmomanometer according to an embodiment of the present invention, FIG. 2 is a flow chart showing the operation of the device, and FIGS. 3 and 4 are diagrams showing pressure correction curves by the device. FIG. 5 is a flow chart showing the operation in the conventional example, FIG. 6 is a diagram showing a pressure drop curve during natural exhaust, and FIG. 7 is a diagram showing a pressure drop curve during forced exhaust. 1 ... Pressure sensor, 2 ... Storage means, 3 ... Pressure detection means, 4 ... First determination means, 5 ... Timing means, 6 ... Second determination means.

Claims (1)

[Claims] Storage means for storing the output of the pressure sensor at power-on as a correction value, and pressure detection means for subtracting the correction value from the output of the pressure sensor at the time of pressure measurement to detect the pressure at each predetermined sampling cycle, A first determining means for determining that the pressure has become negative, a timing means for measuring a predetermined time after the pressure has become negative, and a second determining means for determining that the pressure has increased for each sampling cycle. The pressure of the electronic sphygmomanometer, which comprises a determining means and uses the output of the pressure sensor as a new correction value when the pressure has not increased within the predetermined time after the pressure becomes negative within the predetermined time. Corrected equipment value.