JPS6354147A - Continuous blood pressure measuring apparatus - Google Patents

Abstract

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

Description

TECHNICAL FIELD The present invention relates to a continuous blood pressure measuring device, and more particularly to a continuous blood pressure measuring device that displays a provisional systolic blood pressure value before displaying the blood pressure value at the end of each blood pressure measurement. It is something.

Conventional technology Pulse synchronized waves, such as Korotkoff sounds, generated with changes in pressure of a cuff wrapped around a part of a living body are sequentially collected by a pulse synchronized wave detection means, and based on changes in the magnitude of the pulse synchronized waves, BACKGROUND ART Continuous blood pressure measurement devices that continuously measure blood pressure values of a living body are known.

In such a device, the systolic blood pressure value and the diastolic blood pressure value are displayed at the end of each blood pressure measurement, but the internal hypertension value of these blood pressure values is usually an important indicator. It is desired to display provisional systolic blood pressure values at an early stage without waiting until the systolic blood pressure value, diastolic blood pressure value, etc. are finally determined and displayed.

Problems to be Solved by the Invention However, when determining a provisional systolic blood pressure value at the time of each blood pressure measurement, the maximum value of the difference between the pulse synchronized waves that are sequentially collected corresponding to the provisional systolic blood pressure value. However, in this case, the maximum value of the difference is updated sequentially and it is difficult to accurately detect the provisional systolic blood pressure value at once.
The temporarily displayed systolic blood pressure value may be sequentially changed as pulse-synchronized waves are subsequently collected.

Means for Solving the Problems The present invention has been made against the background of the above circumstances.
The gist thereof is to provide a continuous blood pressure measuring device as described above, in which (a) when a predetermined number or more of the pulse synchronized waves are collected at each blood pressure measurement, the magnitude of the pulse synchronized wave is measured; a regression line determining means for determining a regression line based on points indicating the magnitude of the pulse-synchronized wave within two-dimensional coordinates of an axis indicating the axis and an axis indicating the cuff pressure or time; (C) Expected value determining means for determining, on the regression line determined by, the expected value of the magnitude of the pulse synchronous wave next to the pulse synchronous wave used for determining the regression line; and (C) the expected value determining means. Compare the expected value determined by the actual pulse-synchronized wave size,
provisional systolic blood pressure value determining means for determining a provisional systolic blood pressure value based on the fact that the actual pulse-synchronous wave exceeds the expected value;
d) display means for displaying the provisional systolic blood pressure value determined by the provisional systolic blood pressure value determining means prior to the true systolic blood pressure value determined thereafter;

By doing so, when a predetermined number or more of pulse synchronized waves are collected during each blood pressure measurement, the regression line determining means determines the point indicating the magnitude of the pulse synchronized wave within the two-dimensional coordinates. Based on this, a regression line is determined, and on the regression line, the expected value determining means determines the expected value of the magnitude of the pulse synchronous wave following the pulse synchronous wave used to determine the regression line. Then, the provisional systolic blood pressure value determining means compares the expected value with the magnitude of the actual pulse-synchronous wave, and determines a provisional systolic blood pressure value based on the fact that the actual pulse-synchronous wave exceeds the expected value. At the same time, the provisional systolic blood pressure value is displayed by the display means prior to the true (official) systolic blood pressure value that is subsequently determined.

Effects of the Invention As a result, a provisional systolic blood pressure value can be determined at an early stage without waiting until the true systolic blood pressure value is displayed at each time of blood pressure measurement. Moreover, since the provisional systolic blood pressure value is determined based on the fact that the actual pulse-synchronous wave exceeds the expected value determined on the regression line, the provisional systolic blood pressure value is determined based on the maximum value of the difference between each pulse-synchronous wave. Compared to the case of determining the maximum pressure control value, the temporarily displayed temporary systolic blood pressure value is not changed, and a value with a relatively high degree of confidence is temporarily displayed.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 2 is a diagram showing a control circuit of a continuous blood pressure measuring device to which the present invention is applied, and 10 is a rubber bag-shaped cuff that is wrapped around the upper arm of a human body. A pressure sensor 12, an air pump 14, a throttle 16 and a solenoid valve 18 for slow deflation, and a solenoid valve 20 for rapid deflation are connected to the cuff 10 via piping 22, respectively. Pressure sensor 12 supplies a pressure signal sp representative of the pressure within cuff 10 to static pressure discrimination circuit 24 .

The static pressure discrimination circuit 24 is equipped with a low-pass filter, and is configured to detect a cuff pressure signal S representing a steady pressure included in the pressure signal sp.
K is discriminated and the cuff pressure signal SK is supplied to the CPU 28 via the A/D converter 26.

A microphone 30 is provided inside the cuff 10. The microphone 30 detects a pulse sound (Korotkoff sound, hereinafter referred to as sound) generated from the upper arm of the subject, and supplies a sound signal SO representing the K sound to the bandpass filter 32. This second sound corresponds to the pulse synchronized wave of this embodiment. The bandpass filter 32 passes a signal having a frequency component of approximately 30 to 80 t (z), and transmits the passed sound signal S to the CPU 2 via the A/D converter 34.
Supply to 8.

The CPU 28 is connected to the ROM 36 via the data bus line.
RAM 38, display 40, and output interface 4
The air pump 14 and the solenoid valves 18 and 20 are connected to the air pump 14 and the electromagnetic valves 18 and 20.
At the same time, it executes a series of blood pressure measurement operations, determines a predetermined blood pressure value based on the K sound signal SO, cuff pressure signal SK, etc., and displays the determined blood pressure value on the display 40.

Hereinafter, the operation of this embodiment will be explained according to the flowchart shown in FIG.

When the power is turned on, initial processing in step S1 is executed. Next, by executing step S2,
It is determined whether blood pressure measurement has started based on whether the measurement start pushbutton switch 44 has been operated or whether a timer counter provided in a starting circuit (not shown) has expired.

If this judgment is negative, step S2 is repeatedly executed and the standby state is entered, but if the judgment of step S2 is affirmative, step S3 is executed and both solenoid valves 18 and 20 are activated. Both are brought into a closed state, and the air pump 14 is started to raise the pressure inside the cuff 10. Next, in step S4, it is determined whether the cuff pressure P exceeds a predetermined constant target cuff pressure Pm. This target cuff pressure Pm is a pressure that is sufficiently higher than the systolic blood pressure value, for example, a value of about 180 mmHg.

When the cuff pressure P has not yet exceeded the target cuff pressure Pm, steps S3 and S4 are repeatedly executed, but when the cuff pressure P exceeds the target cuff pressure Pm, step S5 is executed and the air pump 14 is activated. At the same time, the solenoid valve 18 is opened, and a gradual pressure reduction of the cuff 1O is started. , Continued (In step S6, an index counter i is cleared. This index counter i indicates the index of data representing the volume of the sound and the cuff pressure P at that time, which will be described later. Next, step S7 When executed, the K sound signal S
It is determined whether or not O has been collected. If this judgment is negative, step S7 is repeatedly executed, but if it is affirmative, the current cuff pressure It is stored in RAM:3B together with P. Therefore, in this embodiment, step S7, the microphone 30, the bandpass filter 32, and the like constitute a pulse synchronous wave detection means. In the following step S8, it is determined whether the flag F is 1 or not.

When this flag F is 1, it indicates that a provisional systolic blood pressure value has been determined, and when it is 0, it indicates that a provisional systolic blood pressure value has not yet been determined. If the judgment in step S8 is negative, step S9 is executed, and 1 is added to the index counter i, and the Ste-Knob SIO is executed to store the sound in the storage location corresponding to the index counter i. Data representing the size and the cuff pressure P at that time are respectively stored. Step S11
In this step, it is determined whether the index counter i is, for example, 5 or more, that is, whether 5 or more sounds have been sampled. If this judgment is negative, steps S7 to 311 are repeatedly executed and the sounds are sequentially sampled, but if the judgment of step Sll is affirmative, the following step S12 is executed and the K sound is collected. A regression line is determined based on the points representing the magnitude of the K sound within the two-dimensional coordinates of the axis representing the magnitude of P and the axis representing the cuff pressure P. That is, for example, if sound data is obtained as shown in FIG. is determined. In the subsequent step S13, on the regression line a, the expected value of the next sound after the next sound, that is, the next sound corresponding to the inte-nox counter i-4, is determined on the regression line a. Th1 and an expected value Th2 of the loudness corresponding to the index counter i are respectively determined. In this embodiment, step S12 corresponds to regression line determining means, and step S13 corresponds to expected value determining means.

Next, by executing step S14, the actual sound volume K corresponding to the index counter i-1 is
It is determined whether or not (i-1) is larger than the expected value Thl. If this determination is negative, steps S7 to S14 are repeatedly executed; however, if the determination in step S14 is affirmative, The following step 515 is executed. In step S15, the actual sound volume K
It is determined whether or not (i) is larger than the expected value Th2, and if this determination is affirmative, the subsequent step 816 is executed, whereby the sound is sampled to a magnitude K(i-1). The cuff pressure PI at that time is determined as a provisional systolic blood pressure value. Next, in step S17, the flag F is set to 1.
At the same time, step S18 is executed and the systolic blood pressure value of the plate is displayed on the display 40. therefore,
In this embodiment, steps S14 to S16 perform provisional systolic blood pressure value determination means, step 318 and display 40
etc. constitute the display means.

If the judgment in step S15 is negative, step S19 is executed so that the sound volume K(i) corresponding to the index counter i becomes K(i-1).
At the same time, step 320 is executed and the inte-nox counter i is set to i-1. As a result, the sound data that is determined to be smaller than the expected value Th2 in step S15 is deleted, and the sound data in steps S7 to 3 are deleted until the determination in step S15 is affirmed.
15 and step 519. S20 is repeatedly executed.

When the provisional systolic blood pressure value is displayed in step SI8, the blood pressure value determination routine in step S21 is executed, so that the systolic blood pressure value and the diastolic blood pressure value are determined based on the change in the volume of each sampled sound. A well-known blood pressure value determination algorithm is executed to determine the systolic blood pressure value, diastolic blood pressure value, etc. In the following step S22, it is determined whether blood pressure measurement has been completed. If blood pressure measurement has not been completed, steps S7 and S8 will be executed, but since flag F is determined to be 1 in step S8, steps S9 to S20 will be skipped. Step S7. S8゜S21. S22 is repeatedly executed. If it is determined in step S22 that blood pressure measurement has been completed, step S23 is executed and the flag F is cleared. Next, when step S24 is executed, the blood pressure value is displayed on the display 40, and the solenoid valve 20 is opened as necessary to close the cuff 1.
The pressure inside 0 is rapidly exhausted. Thereafter, steps S2 and subsequent steps are executed again to continuously measure blood pressure.

In this way, according to the present embodiment, a provisional systolic blood pressure value is determined at an early stage without waiting until the true systolic blood pressure value is displayed at each time of blood pressure measurement. Furthermore, since the provisional systolic blood pressure value is determined based on the fact that the actual loudness of the sound exceeds the expected value determined on the regression line, the maximum value of the difference between the loudness of each sound Compared to the case where a provisional systolic blood pressure value is determined based on this, the temporarily displayed provisional systolic blood pressure value is not changed, and a value with relatively high confidence is provisionally displayed.

Furthermore, according to this embodiment, the two actual sound magnitudes K
(i-1) and K (i) are both judged to be larger than the expected values Thl and Th2, then the K(i-1)
Since the configuration is such that the cuff pressure P corresponding to P is determined as the provisional systolic blood pressure value, the reliability of the provisional systolic blood pressure value is further improved.

Furthermore, according to the present embodiment, there is no need to smoothen each sampled sound signal SO, so a provisional systolic blood pressure value can be determined relatively quickly.

In addition, in the above-mentioned example, the expected values are determined for the loudness of the next two sounds and the next two sounds used to determine the regression line, and the actual loudness of the sound is determined. When both exceed these expected values, the cuff pressure P at which the sound was taken immediately after the sound used to determine the regression line is determined as the provisional systolic blood pressure value, but this is not necessarily necessary. For example, when the actual sound volume exceeds two or more expected values, the cuff pressure P is calculated based on the cuff pressure P when the sound was sampled at any of the times corresponding to the second and subsequent expected values. It may be determined, or it may be determined based on the average of each cuff pressure P when a plurality of actual sounds exceeding each expected value are respectively sampled.

Furthermore, in the above-mentioned embodiment, when five or more K sounds are sampled, the regression line is determined based on the points indicating the loudness of three of them. However, this is not necessarily necessary; if at least three K sounds are sampled, the regression line can be determined, and the regression line may be determined based on four or more K sounds.

Furthermore, in the above-mentioned embodiment, the regression line is determined within the two-dimensional coordinates of the axis representing the loudness of the K sound and the axis representing the cuff pressure P. It may be determined within the two-dimensional coordinates of the axis indicating the time and the axis indicating the time.

In addition, in the above embodiment, each sampled sound signal S
The regression line may be determined after smoothing O.

Further, in the above-mentioned embodiment, the blood pressure value determination routine is executed in response to the acquisition of the sound signal SO after the provisional systolic blood pressure value is determined, which is a so-called real-time process, but this is not necessarily necessary. , it is also possible to determine the blood pressure value by so-called hatch processing after all K sound signals SO have been collected.

In addition, various changes may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to claims of the present invention. FIG. 2 is a block diagram showing one embodiment of the present invention. FIG. 3 is a flowchart for explaining the operation of the embodiment shown in FIG. FIG. 4 is a diagram showing an example of a sampled sound signal, and is a diagram for explaining a regression line and an expected value. 10: Cuff 30; Microphone 32: Bandpass filter 40: Display device Applicant Nippon Kolin Co., Ltd. Figure 1 Figure 4 Cafe P

Claims (1)

[Claims] Pulse synchronized waves generated as a result of pressure changes in a cuff wrapped around a part of a living body are sequentially collected by a pulse synchronized wave detection means,
A continuous blood pressure measuring device that continuously measures the blood pressure value of the living body based on changes in the magnitude of the pulse synchronized wave, wherein a predetermined number or more of the pulse synchronized waves are collected at each blood pressure measurement. regression line determining means for determining a regression line based on points indicating the magnitude of the pulse synchronous wave within two-dimensional coordinates of an axis indicating the magnitude of the pulse synchronous wave and an axis indicating cuff pressure or time; and expected value determining means for determining, on the regression line determined by the regression line determining means, an expected value of the magnitude of a pulse synchronous wave following the pulse synchronous wave used to determine the regression line. A temporary maximum value is determined by comparing the expected value determined by the expected value determination means with the magnitude of the actual pulse-synchronous wave, and determining a provisional systolic blood pressure value based on the fact that the actual pulse-synchronous wave exceeds the expected value. A continuous blood pressure system characterized by comprising: a hypertension value determination means; and a display means for displaying the provisional systolic blood pressure value determined by the provisional systolic blood pressure value determination means prior to the true systolic blood pressure value determined thereafter. Blood pressure measuring device.