JPS5820626B2 - automatic blood pressure monitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic sphygmomanometer that can automatically measure systolic and diastolic blood pressure values and display the measured values simply by a starting operation.

In general, the standard clinical method for indirect blood pressure measurement is based on Korotkoff's auscultation method.

That is, since the upper arm has an artery near the epidermis, a cuff band is wrapped around the upper arm and air pressure is applied into the cuff band at a rate of 20 to 301 nrIIHg/sec.

The pressure value of this cuff band is 10 to 20 times higher than the expected systolic blood pressure value.
If the pressure is increased to a high miHg, the artery will be compressed and blood flow will stop.

Next, when the air pressure in the cuff band, that is, the cuff pressure, is gradually evacuated at a rate of 2 to 3 mmHg/sec, the artery opens slightly, and the arterial wave blood flow increases at a high speed during cardiac systole. When the arterial waves begin to pass through the arteries that have been opened, the arterial waves flow laterally through the blood vessel walls, causing damped vibrations with a higher frequency than the arterial waves as so-called Korotkoff sounds, and the cuff pressure at this time is determined as the systolic blood pressure level. In addition,
As the cuff band continues to be evacuated gradually, Korotkoff sounds appear in synchronization with the arterial waves, and the position of the Korotkoff sounds gradually moves from the systole to the diastole in the arterial waves. When the Korotkoff sound occurs during diastole, the arteries have already opened and the blood flow is no longer constricted, so the Korotkoff sound disappears, and the cuff pressure at this time is taken as the diastolic blood pressure value. In this way, the systolic/diastolic blood pressure values are indirectly determined.

Therefore, when attempting to automatically measure blood pressure using the indirect blood pressure measurement method described above, it is necessary to
After increasing the cuff pressure to a high pressure value of mmHg, an automatic pressurization device is configured to gradually lower the cuff pressure, and a microphone attached to the cuff band is used to accurately suppress the onset and disappearance of Korotkoff sounds. It is necessary to discriminate and recognize.

In this case, in the latter case, it is possible to recognize Korotkoff sounds with some degree of certainty using electric circuit means, but in the former case, the systolic blood pressure value differs depending on the actual individual being measured, so the cuff band should be adjusted accordingly. There is a problem in that it is difficult to determine the maximum pressurization value.

For this reason, in conventional automatic blood pressure monitors, as shown in the pressure state diagram of the cuff band shown in Fig. 1 and the flowchart shown in Fig. 2, pressurization of the cuff band is repeated by applying pressure and interrupting the pressurization. Based on whether the Korotkoff sound is recognized or not when the pressurization is interrupted, it is determined whether or not to perform the next pressurization, and the process moves to the next step of blood pressure measurement in which the Korotkoff sound is not recognized. I was doing it.

That is, after wrapping the cuff band around the upper arm and putting on the cuff band and turning on the power switch, when the measurement push button switch is turned on at time t1, the pressure pump is started and the cuff pressure is increased as shown in Fig. 1. is rapidly raised.

This initial pressurized air delivery is performed at a cuff pressure of 120 mmHg ~
The cuff pressure is set to about 130 mmHg, and the cuff pressure is set to about 120 mmHg in the cuff pressure measurement circuit.
When it is detected at time t2 that the temperature has reached mmHg to 130 mmHg, the pressurization of the cuff band is temporarily interrupted, and the Korotkoff sound discrimination operation is performed for re-pressurization discrimination.

Thus, when the cuff pressure at this time has not reached the systolic blood pressure value of the individual to be measured, the blood flow is not completely blocked due to the pressurization of the cuff band, so that at time t3 during the above-mentioned Korotkoff sound discrimination operation. When the Korotkoff sound is recognized and detected, time T1 is set as the re-pressurization time, the pressurizing pump is started again at the above-mentioned time t3, and re-pressurizing is started again at time t4 after time T has elapsed. The process is interrupted and a Korotkoff sound discrimination operation is performed.

This pressurization interruption and Korotkoff sound discrimination operation is repeated until Korotkoff sound recognition and discrimination are no longer performed during the Korotkoff sound discrimination operation, and the repressurization started at time t5 is interrupted at time t6. After that, when no Korotkoff sounds are detected during the operation period of Korotkoff sound discrimination that continues for 12 hours, the exhaust valve for exhausting the pressurized air in the cuff band is opened at time t7, as shown in FIG. As such, the cuff pressure in the cuff band is gradually exhausted.

At this time, the above-mentioned slow exhaustion by the exhaust valve is continued until the first Korotkoff sound is recognized and determined, and when the first Korotkoff sound is recognized and determined, the cuff pressure value at this time is memorized as the systolic blood pressure value. Then, while the display is displayed, the slow exhaust is further continued, and this slow exhaust state is continued as long as the Korotkoff sound is detected.

After this, when the cuff pressure drops sufficiently and the constriction of blood flow due to the pressurization of the cuff band completely disappears, Korotkoff sounds will no longer be detected, so the cuff pressure value at the time of this final Korotkoff sound detection will be stored as the diastolic blood pressure value. After this is displayed, the pressurized air in the cuff band is rapidly exhausted and the measurement is completed.

However, in such a conventional example, since the opening operation sound of the exhaust valve is generated in the initial stage when the exhaust valve is opened at time t7 and slow exhaustion from the cuff band is started, the Korotkoff sound is not detected for only time T3 from time t2. It was necessary to stop the discrimination operation to prevent misrecognition of Korotkoff sounds.

That is, in the past, in order to prevent malfunctions caused by the opening sound of the exhaust valve, the Korotkoff sound detection and discrimination operation was performed at time t8, 13 hours after the slow exhaust was started at time t7. If the first Korotkoff sound occurs during the period of There was a problem.

The present invention has been provided in view of the above-mentioned points, and when the detection and recognition of the Korotkoff sound is no longer performed during the cuff pressurization process when the cuff pressure is interrupted, the cuff pressure is temporarily reapplied and then the cuff band is An object of the present invention is to provide an automatic sphygmomanometer that starts slowly discharging pressurized air from the systolic blood pressure, thereby preventing erroneous measurements of systolic blood pressure.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 3 shows a block diagram of an embodiment of the present invention, and the circuit configuration shown in this block diagram is the same as that of the conventional example described above.

Further, FIG. 4 is a pressure state diagram of the cuff band corresponding to FIG. 1 of the conventional example, and FIG. 5 is a flow chart corresponding to FIG. 2 of the conventional example.

In the circuit shown in Fig. 3, 1 is a cuff band, 2 is an automatic pressurization device composed of a pressurizing pump 10, a slow exhaust valve 11, and a rapid exhaust valve 12, and 3 is a Korotkoff sound detection converter, which is used together with the cuff band 1. It constitutes the Korotkoff sound detection section 13.

Reference numeral 14 denotes a diaphragm connected to the cuff band 1 via the electric body 4, which detects the cuff pressure and operates the differential transformer 15.
The output of the differential transformer 15 corresponding to the eccentric position of the diaphragm 14 is converted into a DC signal by the rectifier circuit 17, and converted into a digital signal by the A/D converter 18.

However, the above-mentioned diaphragm 14, differential transformer 15,
Pressure conversion circuit section 19 by drive circuit 16 and rectifier circuit 17
A storage display calculation section 21 is constituted by an A/D converter 18 and a digital display section 20 having two display sections.

Furthermore, in the figure, 22 is a Korotkoff sound recognition/discrimination circuit, and 23 is an operation control circuit.

The operation control circuit 23 is configured using, for example, a microcomputer, and controls the entire sequence operation of automatic blood pressure measurement.

Thus, the automatic blood pressure monitor of the present invention is the same as the conventional example described above until the operation period of Korotkoff sound discrimination continues for 72 hours after repressurization is interrupted at time t6, and this period ends at time t7. However, in the present invention, after time t7, the pressurizing pump is started again to apply additional pressure for a predetermined time, and then at time t8.
After stopping the additional pressurization, the slow exhaust valve 11 is opened and a valve sound ignoring time T3 is set, the pressurized air in the cuff band 1 is gradually exhausted, and the Korotkoff sound recognition discrimination is performed only during the T3 time. The operation is stopped, and the above T is reached at time t9.
After 3 hours have elapsed, the systolic/diastolic blood pressure values are measured by Korotkoff sound recognition discrimination, similar to the conventional example.

Since the present invention is configured as described above, even if the Korotkoff sound is not recognized and determined when re-inflation is interrupted, the cuff band is temporarily added without immediately transitioning to the exhaust stroke for blood pressure measurement. After pressurizing, the air is evacuated for blood pressure measurement, and after a certain period of time has elapsed to ignore the valve sounds, the Korotkoff sound for blood pressure measurement is recognized and discriminated. Blood pressure measurement is started from the pressure value, and the first Korotkoff sound indicating the systolic blood pressure value is not overlooked, making it possible to accurately measure the blood pressure value.

[Brief explanation of the drawing]

Fig. 1 is a pressurizing state diagram of the can belt in the conventional example, Fig. 2 is a flowchart of the same as above, Fig. 3 is a block diagram of an embodiment of the present invention, and Fig. 4 is a pressurizing state diagram of the cuff band same as above. , FIG. 5 is a flowchart similar to the above, in which a is the upper arm, b is the artery, 1 is the cuff band, and 2 is the automatic pressurization/decompression device.

Claims (1)

[Claims] 1 Wrapped around the upper arm etc., pressurized air is forced into the cuff band until the artery is completely occluded, and after the artery is completely occluded by this pressurized air supply, the cuff is automatically turned into an evacuation state. Equipped with an automatic pressurization/depressurization device that gradually exhausts the pressurized air in the cuff band by switching the air to the maximum level during the cuff exhaust stroke.
An automatic blood pressure monitor that detects the diastolic blood pressure value and displays the detection result is configured so that pressurized air is fed to the cuff band by an automatic pressurization/depressurization device by repeatedly applying pressure and interrupting pressurization. and a re-pressurization determination means for starting re-pressurization of the cuff band when Korotkoff sounds are detected from the cuff band when the pressurization is interrupted, and a re-pressurization determination means that starts re-pressurizing the cuff band when the Korotkoff sounds are detected from the cuff band when the pressurization is interrupted. an additional pressurization determination means that starts additional pressurization of the cuff, and at the end of the above additional pressurization, switches to an exhaust stroke that gradually exhausts the pressurized air in the cuff band, and after a predetermined time elapses, a maximum/minimum judgment based on Korotkoff sound recognition. An automatic blood pressure monitor characterized in that an automatic pressure increase/decrease device is equipped with a blood pressure measurement start means for starting blood pressure value measurement.