JPS6349133A - Electronic hemomanometer - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an electronic blood pressure monitor.

The configuration of a conventional electronic blood pressure monitor is shown in FIG. The conventional measurement principle will be explained based on FIGS. 5 and 6. First, the arm cuff 1 is attached to the upper arm of a human body. Next, air is blown into the cuff 1 through the rubber tube 3 using the rubber bulb 2 to pressurize it to a constant pressure. When the air supply by the rubber bulb 2 is stopped, a small amount of air is discharged from the micro-exhaust valve built into the rubber bulb 2,
The pressure within the cuff 1 gradually decreases. Further, the pressure inside the cuff 1 is detected by a pressure sensor 4 connected to a rubber tube 3, and the output of the pressure sensor 4 is converted into a digital pressure signal by an A/D converter 5 and becomes an input to the CPU e.

Next, a method of processing the digital pressure signal detected by the CPU e will be explained. The period from the completion of pressurization to the completion of measurement is referred to as the measurement mode, and the period thereafter until the completion of exhaustion is referred to as the exhaust mode.

In the measurement mode, first set the initial values in step 3.
3) The pressure signal P during slight evacuation is detected at fixed time intervals (steps 34 and 35). Next, the measured pressure signal P, is compared with the previous value Pi-1, and when p,>p, . . ., the process proceeds to the next step (step 36). Pressure value Pi
-1 is stored as the pressure PN when the pressure vibration occurs, and the time at that time is stored as TN = (i - i) k (step 37).

Subsequently, the pressure signal Pi is detected at regular intervals (Steps 38 and 39), and the maximum value of P and glue is determined (Step 4 (1). The extremely thick value P of P is determined.

The difference between and PN is set as QN and is stored as the magnitude of pressure vibration (step 41). Next, for N22, the correction value RN for the magnitude of pressure vibration depending on the pumping speed is RN=(PN-1”N
) x "O/("N-TN-1)'1 (step 42). T here. is the average time from TN to reaching the maximum value Pm, and kl is T. This is the standard displacement between the two, and it is corrected only if it differs from the standard displacement.

Next, in the case of N22, the correction value RN is set to the magnitude of pressure vibration ON.
is added and stored as the magnitude of pressure vibration QN'. N=
If it is 1, it is stored as Ql'=01+R2 (step 43).

Next, it is determined whether Qi has reached the maximum value (step 46). If the maximum value of Q is not determined, N is incremented and steps 34 to 45 are repeated. Q,
When the maximum value of QNmax is determined, the pressure value PN at the first 00, which is the detection level determined by k2QNmax.
Let be the systolic blood pressure, k3QN, ? The pressure value PN at the first Qi below 1ax is determined to be the diastolic blood pressure (step 46). If the conditions are not met, steps 34 to 46 are repeated. The determined blood pressure value is displayed on the display 7 (step 47).

Problems to be Solved by the Invention (2) In the conventional electronic blood pressure monitor, an increase in the pressure signal must be detected when detecting pressure vibrations. Therefore,
Pressure oscillations could not be detected when the pressure discharge speed was high or when the pressure oscillations were small. In addition, when correcting pressure oscillations due to pressure drop speed, the correction amount was the value obtained by multiplying the fall speed by a certain fixed time.
The correction value was incorrect.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an arm cuff to be worn on the upper arm of a human body, and a pressurizing means for supplying air to the arm cuff to pressurize the upper arm of the human body until blood ischemia is achieved. , a slight evacuation means for gradually evacuation, and a pressure detection means for detecting the pressure within the cuff at regular sampling times.

a conversion means for converting the output of the pressure detection means into a digital pressure signal; a first calculation means for calculating the difference between the current value and the previous value of the digital pressure signal; a first detection means for detecting that the digital pressure signal has started to increase; a first storage means for storing the pressure value at the point of increase in the difference between the digital pressure signals; and a second storage means for calculating the rate of decline of the digital pressure signal. a third calculating means for calculating the instantaneous value of the pressure oscillation occurring during the minute evacuation from the current value of the digital pressure signal and the rate of descent; a second storage means for storing the magnitude of the pressure oscillations generated in the pressure oscillation, a second detection means for detecting the maximum value of the pressure oscillation, and a determination for determining the blood pressure value from the magnitude of the pressure oscillation and its maximum value. and display means for displaying the blood pressure value.

Function: With the above-described configuration, the present invention can detect pressure oscillations even when the pressure signal does not increase due to a large pressure discharge speed or a small pressure oscillation.

Furthermore, by correcting pressure oscillations using the minute drainage speed, accurate pressure oscillations can be obtained, and blood pressure can be determined accurately regardless of the minute drainage speed.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 4. The basic configuration of the electronic blood pressure monitor of this embodiment is as shown in FIG. 4 described above, and first, the cuff 1 is worn on the upper arm of a human body. Next, air is blown into the cuff 1 through the rubber tube 3 using the rubber bulb 2, and the pressure is increased to a certain level. This period is called pressurization mode. Next, the pressure is gradually reduced by evacuation through a micro-exhaust valve built into the rubber bulb 2. Further, the pressure within the cuff 1 is detected by a pressure sensor 4 connected to a rubber tube 3, and the output of the pressure sensor 4 is converted into a digital pressure signal by an A/D converter 5, which is input to the CPU e.

Next, a method of processing the digital pressure signal detected by the CPU e will be explained with reference to FIGS. 1 to 3. The period from the completion of pressurization to the completion of measurement is referred to as the measurement mode, and the period thereafter until the completion of exhaustion is referred to as the exhaust mode.

In measurement mode, first make settings (step 8).
), the pressure signal P during slight evacuation is detected at every fixed sampling time (step 9.1(1)).

The difference Δ between the next measured pressure signal P□ and the previous value P1-1
Take Pi""1-Pi-1 (step 11) and JP.

It is determined whether the 01st increase is being detected (M=o) (step 12). If M=o, JP/7th previous ΔPi-1
(step 73), and when ΔP is ΔP1-1, the process returns to pressure measurement (step 9).

When ΔPi>ΔPi-1, ΔPi-1 is stored in DP as the pressure at the time when the pressure difference starts to increase (DP=Δp, -,
) (step 14). Then, increment the number M of JP machining (step 15) and return to the next pressure measurement (step 9). If ΔPi is 0, compare ΔPi and DP (step 16); if ΔP1≦DP, clear M and return to step 9. Below, if ΔP1>DP, it is determined whether M has reached the predetermined number of times K (step 18), and if not, M is incremented (step 16).
), return to Stesoge 9 again. If M = , the start of the pulse is detected and M is cleared (Step 19), the pressure value and time at the start of the pulse are set to PN = Pi-, and T
Store as N = 1-1c (step 2 (1). Next, determine whether the current beat is the 1st beat or not (step 21),
In the case of the second cuff or later, the vibration component of the pulse is determined in the next steps 21 to 27. First, the rate of descent between the current and previous beats is FtN = (pN-1-PN)A(TN -TN-
1) (step 22). Next, the next pressure measurement is performed (steps 23 and 24), and the instantaneous value of the pulse size is corrected by the descending speed RN, and qi=P knee (PN-
RNk(i-TN)) (step 26).

Thereafter, it is determined whether q has reached the maximum value (step 26), and if it has not, the process returns to the next pressure measurement (step 23.24). Once the local maximum value is determined, the local maximum value of qi is stored as ON (step 27).

An explanatory diagram of the above pressure vibration detection method is shown in FIG. Next, if the current number of beats is o (N=1), then 0N=01=O
(Step 28). Next, it is determined whether KQN has reached the maximum value (Step 29), and if it has not reached the maximum value, N
(step 3 (1), and repeat steps 9 to 30 until the maximum value of ON is determined. QN
When the maximum value of is determined to be QN max, kI QNm
Pressure value P at the first QN, which is the detection level determined by step a
Let N be the systolic blood pressure, and the first QN below k2Qma
The pressure value PN at the time of is determined to be the diastolic blood pressure (step 31
).

If the conditions are not met, repeat steps 9 to 31.

The determined blood pressure value is displayed on the display 7 (step 32
).

Effects of the Invention As described above, according to the present invention, pressure oscillations can be detected even when the pressure signal does not increase due to a high pressure discharge speed or a low pressure imaging. Furthermore, by correcting pressure oscillations using the minute drainage rate, accurate blood pressure can be determined regardless of the minute drainage rate.

[Brief explanation of drawings]

Fig. 1 is a flowchart of the processing procedure in the CPU of an electronic blood pressure monitor showing an embodiment of the present invention, Fig. 2 is a pressure waveform diagram of the electronic blood pressure monitor, and Fig. 3 is an enlarged view of the main parts of Fig. 2. Waveform diagram, Figure 4 is a block diagram showing the basic configuration of a general electronic blood pressure monitor, Figure 5 is a pressure waveform diagram of a conventional electronic blood pressure monitor, and Figure 6 is a processing procedure in the CPU of a conventional electronic blood pressure monitor. This is a flowchart. 1... Bracelet, 2... Rubber ball, 4...
... Pressure sensor, 5 ... A/D converter, 6.
...CPU, 7...Display unit. Figure 3 Figure 4

Claims (5)

[Claims] (1) An arm cuff to be attached to the upper arm of a human body, a pressurizing means for supplying air to the arm cuff and pressurizing the upper arm of the human body until blood ischemia, a micro evacuation means for gradually discharging air, and an air cuff inside the arm cuff. pressure detecting means for detecting the pressure at every fixed sampling time; converting means for converting the output of the pressure detecting means into a digital pressure signal; and a converting means for calculating the difference between the current value and the previous value of the digital pressure signal. 1 calculation means, and a first detection means for detecting that the difference between the digital pressure signals has started to increase during fine evacuation;
a first storage means for storing the pressure value at the point of increase in the difference between the digital pressure signals; a second calculation means for calculating the rate of fall of the digital pressure signal; and a current value of the digital pressure signal and the rate of fall. a third calculating means for calculating the instantaneous value of the pressure vibration generated during micro-evacuation, and a second memory for storing the maximum value of the instantaneous value of the pressure vibration as the magnitude of the pressure vibration generated during micro-evacuation. a second detection means for detecting the maximum value of the pressure vibration, a determination means for determining a blood pressure value from the magnitude of the pressure vibration and its maximum value, and a display means for displaying the blood pressure value. Electronic blood pressure monitor. (2) A patent in which the first detection means is configured to detect that the difference in the digital pressure signals has started to increase when the value of the difference in the digital pressure signals is consecutively larger than the value at a certain point in time. The electronic blood pressure monitor according to claim 1. (3) The first calculation means is configured to calculate the rate of decline of the digital pressure signal from the change in the previous value and the current value of the point of increase in the difference between the digital pressure signals and the time interval. The electronic blood pressure monitor described. (4) The second calculation means calculates a value obtained by subtracting the product of the point of increase of the difference in the digital pressure signal, the time up to the present time, and the rate of descent from the current value of the digital pressure signal as an instantaneous value of the blood vessel sound. An electronic blood pressure monitor according to claim 1, which is configured to: (5) The determination means determines that the pressure when the magnitude of the pressure oscillation increases as the pressure within the cuff decreases and exceeds a predetermined ratio of the maximum value of the pressure oscillation is the systolic blood pressure; 2. The electronic sphygmomanometer according to claim 1, wherein the blood pressure value is determined by using the pressure at which the pressure decreases as the pressure decreases and becomes equal to or less than a predetermined ratio of the maximum value of the pressure oscillation as the diastolic blood pressure.