JP3462251B2 - Continuous blood pressure measurement device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous blood pressure measuring device, and more particularly to a technique for facilitating confirmation of the circulatory dynamics of a living body. 2. Description of the Related Art The measurement of the blood pressure of a living body is carried out regularly or irregularly for health care and diagnosis, etc., and is performed, for example, on patients who are undergoing surgery or on the circulatory system. When it is necessary to monitor the fluctuation of the blood pressure value as in a certain patient,
It is performed continuously at predetermined time intervals. In such continuous blood pressure measurement, for example, a pulse wave generated from an artery in synchronization with a heartbeat in accordance with a change in the compression strength of an artery of a living body is detected, and a predetermined pulse wave is detected based on a change in the amplitude of the pulse wave. A so-called oscillometric type automatic blood pressure measurement device that determines the blood pressure value of the living body by the blood pressure value determination algorithm, and a Korotkoff (K) sound generated with a change in the compression strength is detected by a microphone, and the K sound is detected. A microphone-type automatic blood pressure measurement device that determines a blood pressure value of a living body based on a change,
Alternatively, a pressure pulse wave sensor that detects a pressure pulse wave generated from the artery is pressed on an artery on the surface of the living body so that a part of the artery is flat, and the blood pressure value is determined based on the change in the pressure pulse wave. An automatic blood pressure measurement device such as a tonometer-type automatic blood pressure measurement device to be determined is used. Therefore, generally, these automatic blood pressure measurement devices are provided with a timer or the like for starting the blood pressure measurement at a predetermined cycle, and an image display device for displaying sequentially measured blood pressure values on a time axis. A display device such as a printer is provided. [0003] The cardiac output (CO) of the living body, that is, the blood flow is an important criterion for determining whether or not sufficient oxygen is supplied to each part of the living body. When it is desired to measure the blood pressure value to continuously monitor the heart function as described above, it is desired to monitor the blood flow at the same time. However, while it is difficult to directly monitor the blood flow, the blood pressure value (BP) of the living body is the product of the peripheral vascular resistance (PR) and the blood flow, BP = PR × CO
It is known that it can be expressed by That is, since the blood pressure value can fluctuate based on the blood flow, the circulatory dynamics is monitored by measuring the blood pressure value as a next best measure. However, as is clear from the above equation, the blood pressure value can also fluctuate due to peripheral vascular resistance, and for example, when peripheral vascular resistance increases despite lower blood flow, the blood pressure value increases. Will be measured. And, because its peripheral vascular resistance is easily changed by various factors such as body temperature, drugs, and nervous system,
Fluctuations in blood flow, that is, the circulatory dynamics of the arteries of the living body cannot be reliably monitored only by monitoring the blood pressure value, and it is possible that abnormalities cannot be dealt with promptly. [0004] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a continuous blood pressure measurement device capable of reliably monitoring the circulatory dynamics of a living body. SUMMARY OF THE INVENTION In order to achieve the above object, the gist of the present invention is to provide an oscillometric continuous blood pressure measuring apparatus of a type in which measurement of a blood pressure value of a living body is repeated at a predetermined cycle. (A) a display device having a display surface on which pixels are two-dimensionally arranged, and (b) a display device for a part of a living body.
As the compression strength of the cuff changes, the cuff
Changes in the amplitude of a series of pressure oscillations
Blood pressure value determining means for determining the blood pressure value by:
Determines the amplitude value of the pressure vibration wave with the maximum amplitude among the pressure vibration waves
Maximum amplitude value determining means, and ( d ) the repeatedly measured blood pressure value and the maximum amplitude value when the respective blood pressure value is measured, a common time axis on the display surface of the display. And display control means for displaying a graph along the line. In this manner, the cuff is attached to the heart.
Change in amplitude of a series of pressure vibration waves generated in synchronization with the beat
While the blood pressure values continuously measured by the oscillometric method are sequentially displayed on the display surface of the display by the display control means, a series of pressures when the blood pressure values are determined are determined.
Since the maximum amplitude value of the force vibration wave is displayed as a graph along the common time axis with the blood pressure value by the display control means, the two can be easily compared. The pressure oscillation wave is generated by blood being periodically pumped from the heart into the tissue of a living body via an artery, and has a maximum amplitude value.
The size of closely related to the cardiac output. Therefore, by comparing the change in the blood pressure value and the change in the maximum amplitude value , the change in the blood flow, that is, the circulatory dynamics of the living body can be reliably monitored. That is, when the peripheral vascular resistance increases due to the contraction or occlusion of the blood vessels, the blood pressure value (particularly, the minimum blood pressure value) tends to be high and the maximum amplitude value tends to be small. Blood pressure (especially systolic blood pressure), maximum amplitude
Both values tend to decrease. On the other hand, when the cardiac output decreases due to a decrease in cardiac function, both the blood pressure value (particularly, the systolic blood pressure value) and the maximum amplitude value tend to decrease (however, it is slightly different from the case where the above-described peripheral vascular resistance decreases). Shows a different tendency). From the above, when neither the blood pressure value nor the maximum amplitude value has a large change, the circulatory dynamics of the living body, that is, the cardiac output (that is, blood flow) and the peripheral vascular resistance are all abnormal. It can be estimated that it has not occurred.
Conversely, when a large change occurs in at least one of them, it is possible to estimate the abnormality or the like that has occurred by comparing the change with a change conceivable from the combination of the above tendencies. Therefore, it is possible to immediately detect abnormalities in the circulatory dynamics of the living body and immediately perform treatment, and to easily determine the effects of administration of a hypotensive agent or the like during surgery, for example. Moreover, the heart is closely related to cardiac output
The pressure detected for measuring the blood pressure value as a beat synchronization wave
Of the vibration wave extracted by the maximum amplitude value determining means.
Since the amplitude value of the large amplitude is used,
The advantage is that it is not necessary to provide the outlet means separately from the blood pressure measurement means.
is there. An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an example of the configuration of an oscillometric blood pressure measuring device which is an embodiment of the continuous blood pressure measuring device according to the present invention, which is wound around the upper arm of a living body and presses it. A pressure sensor 12, a rapid exhaust valve 14, a slow exhaust valve 16, and an air pump 18 are connected to a cuff 10 provided with an inflatable bag through a pipe 20. The pressure sensor 12 detects the pressure in the cuff 10 and outputs a pressure signal SP indicating the pressure in the cuff 10 to the cuff pressure detection circuit 2.
2 and the pulse wave detection circuit 24. The cuff pressure detection circuit 22 detects the cuff 10 which is the static pressure component from the pressure signal SP.
The cuff pressure signal SK is supplied to the control circuit 28 via the A / D converter 26. The pulse wave detection circuit 24 includes a band-pass filter for extracting a pulse wave, which is a vibration component synchronized with a heartbeat, from the pressure signal SP, and controls the pulse wave signal SM via an A / D converter 26. Supply to circuit 28. The control circuit 28 includes a CPU 30, a ROM 3
2, a so-called microcomputer including a RAM 34 and an output interface 36.
The input signal is processed according to a program pre-stored in the ROM 32 while utilizing the temporary storage function of No. 4 to supply drive signals to the quick exhaust valve 14, the slow exhaust valve 16 and the air pump 18, respectively. A signal representing a blood pressure value determined by executing the algorithm, and a signal representing a maximum value of the amplitude value of the pulse wave are displayed on an image display device such as a liquid crystal display panel or a display surface on which pixels are two-dimensionally arranged such as a printer. To display the maximum value of the blood pressure value and the amplitude value. The start switch 40 and the continuous switch 42 are operated to start blood pressure measurement. The start switch 40 is used when blood pressure measurement is performed only once, and the continuous switch 42 is used when blood pressure measurement is performed continuously at predetermined intervals. Operate. In the blood pressure measurement device configured as described above, a series of blood pressure measurement steps are executed as shown in FIG. 2, so that the blood pressure value is automatically measured. That is, it is determined in step S1 whether the start switch 40 or the continuous switch 42 has been operated. Start switch 40 or continuous switch 42
If it is not determined that has been operated, the process is put on standby. If it is determined that any of them has been operated, step S2 is performed.
Is executed, the timer T is set to 0, and step S3
At this time, the quick exhaust valve 14 and the slow exhaust valve 16 are closed, and the air pump 18 is driven to start increasing the pressure of the cuff 10. In step S4, it is determined whether the pressure Pc in the cuff 10 has become equal to or higher than a predetermined target pressure Pm. This target pressure Pm is a pressure sufficiently higher than the systolic blood pressure of the subject, for example, 180
It is set to about mmHg. While the determination in the step S4 is denied, the pressure increase of the cuff 10 is continued.
If the determination in step 4 is affirmative, step S5 is executed to stop the driving of the air pump 18 and to release the slow exhaust valve 16
Is opened, the pressure drop of the cuff 10 is started. In this step of lowering the pressure, the cuff 1 is moved at a speed of about 2-3 mmHg / sec.
The pressure of 0 is slowly changed, and during this time, the blood pressure value is determined by repeatedly executing the blood pressure value determination routine of step S6. In step S6, the subroutine shown in FIG. 3 is repeatedly executed at a relatively short cycle, for example, every 4 ms, so that the amplitude value sequence of the continuously generated pulse wave is preprocessed and the generation is performed. The blood pressure value is determined by executing the blood pressure determination algorithm based on a series of amplitude values that are successively arranged. That is, in step SS1 as the pulse wave detecting means, it is determined whether or not a pulse wave that can be used for measurement has been generated based on the pulse wave signal SM sequentially supplied from the A / D converter 26 at a predetermined sampling cycle. Is determined. The occurrence of this pulse wave is detected by, for example, the occurrence of an upper peak and a lower peak. When the occurrence of the pulse wave is detected in this way, the peak value of the pulse wave, that is, the amplitude value from the upper peak to the lower peak is calculated in step SS2, and the amplitude value is cuffed in the subsequent step SS3. Stored together with the pressure value. Then, a blood pressure determination algorithm for determining a systolic blood pressure value and a diastolic blood pressure value in step SS4 as a blood pressure value determining means is executed. This blood pressure determination algorithm, for example, modifies the stored cuff pressures corresponding to those whose amplitude values have changed abruptly by modifying them in relation to each other and the average blood pressure value as necessary. It is determined and stored as a high blood pressure value and a diastolic blood pressure value. Returning to FIG. 2, after the blood pressure value determination routine of step S6, it is determined whether step S7 has been executed and the blood pressure value has been determined. At the beginning of the cuff pressure drop,
Since the amplitude value sequence is not sufficiently formed, step SS
Even if the blood pressure determination algorithm of No. 4 is executed, the blood pressure value cannot be determined, and the steps following the blood pressure value determination routine of step S5 are repeatedly executed. However, if the blood pressure value is determined by the execution of the blood pressure determination algorithm in step SS4 while step S6 and subsequent steps are repeatedly executed, step S6 is performed.
The determination in Step 7 is affirmed, and Step S8 and subsequent steps are executed. Step S corresponding to the maximum amplitude value determining means
In step 8, the amplitude value of the maximum amplitude pulse wave is determined from the series of pulse waves used for determining the blood pressure value. That is, through the series of steps S3 to S7, as shown in FIG. 4, the pulse wave detection is sequentially performed in the period D in which the cuff 10 is rapidly boosted in the rapid boosting period U and is gradually lowered. In the period D, the blood pressure value is determined based on the pulse wave generated in synchronization with the heartbeat as described above. The pulse wave used for determining the blood pressure value is extracted from the pressure signal SP by the pulse wave detection circuit 24 as described above, and when arranged in the order of generation, the pulse wave having an amplitude value as shown in FIG. A two-dimensional chart of the columns is obtained. From this pulse wave train, the amplitude value of the pulse wave having the maximum amplitude in the measurement period shown in FIG. 4A is determined. Next, in step S9, the quick exhaust valve 14 is operated to rapidly exhaust the air in the cuff 10 and release the compression. In step S10 corresponding to the display control means, the display surface 44 of the display 38 is displayed. For example, as shown in FIG. 6, indicators H indicating the systolic blood pressure and the diastolic blood pressure at the upper and lower ends are displayed in the blood pressure value display area 46 of the upper half of the two-dimensional chart in the order of measurement, and the amplitude values of the lower half are displayed. In the display area 48, the amplitude value of the pulse wave having the maximum amplitude at the time of each blood pressure measurement is displayed as a vertical line on the same time axis. Then, in step S11, it is determined whether or not the mode is the continuous measurement mode. If this determination is denied, the blood pressure measurement is terminated, but if affirmed, the process proceeds to step S12. Note that whether or not the mode is the continuous measurement mode is determined depending on whether the start switch 40 or the continuous switch has been operated in step S1. When the determination at step S11 is affirmed and the routine proceeds to step S12, the operation of the timer T is started, and 1 is added to T. In step S13, whether the value is greater than the measurement period T ₀ that has been set in advance of T is determined. If this determination is denied, the process returns to step S12 and 1 is added to T again. If the determination is affirmative, steps S2 and subsequent steps are executed again to measure the blood pressure. Thus, in the continuous switch 42 has been operated continuous measurement mode, by buck cuff 10 as shown in FIG. 4 is repeated for each set period T _0, at that time continuously the blood pressure value is measured It is displayed together with the amplitude value of the pulse wave having the maximum amplitude. In the continuous measurement mode, the blood pressure measurement is terminated by operating a stop switch (not shown) or by reaching a preset number of measurements or measurement time. Further, as is apparent from the above description, in the present embodiment, the control circuit 28 corresponds to a display control unit. As described above, according to the present embodiment, the continuously measured blood pressure values are sequentially displayed on the display surface 44 of the display 38, while the maximum amplitude at the time when the blood pressure value is determined is determined. Step S8 where the amplitude value of the pulse wave is the maximum amplitude value determining means
And is displayed on the display screen 44 as a graph on the same time axis as the blood pressure value, so that the two can be easily compared. The pulse wave is generated when blood is periodically pumped out of the heart into the tissue of a living body via an artery, and its amplitude is closely related to the blood flow. Therefore, by comparing the change in the blood pressure value with the change in the amplitude value of the pulse wave having the maximum amplitude, the change in the blood flow, that is, the circulatory dynamics of the living body can be reliably monitored. That is, when the peripheral vascular resistance increases due to the contraction or occlusion of blood vessels, the blood pressure value (particularly, the minimum blood pressure value) tends to be high, and the heartbeat synchronizing wave tends to decrease.
Conversely, when the peripheral vascular resistance decreases due to dilation of blood vessels, outflow of blood, etc., both the blood pressure value (particularly the systolic blood pressure value) and the heartbeat synchronous wave tend to decrease. On the other hand, when the cardiac output decreases due to a decrease in cardiac function, both the blood pressure value (particularly the systolic blood pressure value) and the heartbeat synchronizing wave tend to decrease (however, this is slightly different from the case where the peripheral vascular resistance decreases). Different trends)
Is shown. From the above, when neither the blood pressure value nor the heartbeat synchronizing wave has a large change, the circulatory dynamics of the living body, that is, the cardiac output (ie, blood flow) and the peripheral vascular resistance are all abnormal. It can be estimated that it has not occurred. Conversely, when a large change occurs in at least one of them, it is possible to estimate the abnormality or the like that has occurred by comparing the change with a change conceivable from the combination of the above tendencies. Therefore, it is possible to immediately detect abnormalities in the circulatory dynamics of the living body and immediately perform treatment, and to easily determine the effects of administration of a hypotensive agent or the like during surgery, for example. Further, according to the present embodiment, the pulse wave extracted by the pulse wave detection circuit 24 from the pressure signal SP indicating the pressure in the cuff 10 detected for measuring the blood pressure as a heartbeat synchronizing wave corresponds to the step. Since the amplitude value of the maximum amplitude pulse wave extracted by the maximum amplitude value determining means in S8 is used, it is not necessary to provide a heartbeat synchronous wave detecting means independently. While the embodiment of the present invention has been described with reference to the drawings, the present invention can be applied to other embodiments. For example, in the blood pressure value determination routine shown in FIG. 3, the calculated amplitude value is stored as it is and the blood pressure value determination algorithm of step SS4 is executed.
JP-A-63-518, filed and filed by the present applicant,
As disclosed in Japanese Patent Publication No. 37 (Japanese Patent Application No. 61-196231), after step SS2, an abnormal value determination step of comparing the amplitude value detected last time to determine whether the current pulse wave is normal or not. Or a smoothing step for smoothing the amplitude value of the collected pulse wave may be provided. Further, in the above-described embodiment, the blood pressure value is indicated only by the indicators for displaying the systolic blood pressure and the diastolic blood pressure, but the blood pressure value may be displayed in the two-dimensional chart of the display 38 or by a display provided separately. The value may be displayed numerically. The trend of the rate of change of the heartbeat synchronous wave, such as the rate of change of the blood pressure value or the maximum amplitude, or the difference between the rates of change may be displayed on the display 38 or the like. In the above embodiment, the display 3
Although both the blood pressure value and the heartbeat synchronous wave such as the maximum amplitude value are displayed on one display surface 44, two display surfaces having a common time axis are provided on the display 38 side by side, for example, so that One of the amplitude synchronous waves such as the blood pressure value and the maximum amplitude value may be displayed on each display surface. Although not specifically exemplified, the present invention can be variously modified without departing from the gist thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a configuration of an oscillometric automatic blood pressure measurement device which is an example of the present invention. FIG. 2 is a flowchart illustrating the operation of the blood pressure measurement device in FIG. 1; FIG. 3 is a flowchart corresponding to step S5 in FIG. 2; FIG. 4 is a diagram illustrating a change in cuff pressure according to the flowchart of FIG. 2; FIG. 5 is a diagram illustrating the amplitude of a pulse wave collected according to the flowchart of FIG. 2; FIG. 6 is a diagram illustrating a display format of a blood pressure value and an amplitude maximum value output according to the flowchart of FIG. 2; [Description of Signs] 28: Control circuit (display control means) 38: Display 44: Display surface

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61B 5/022 A61B 5/026

Claims (1)

(57) [Claim 1] An oscillometric continuous blood pressure measurement device of a type in which measurement of a blood pressure value of a living body is repeated at a predetermined cycle, wherein a display surface on which pixels are two-dimensionally arranged. With the indicator having the and changing the compression strength of the cuff against a part of the living body
Of the series of pressure oscillation waves generated in the cuff in synchronization with the heartbeat
Blood pressure value determining means for determining a blood pressure value based on a change in amplitude
And the vibration of the pressure vibration wave having the maximum amplitude in the series of pressure vibration waves.
Maximum amplitude value determination means for determining a width value; and the blood pressure values measured repeatedly, and the maximum amplitude value when the respective blood pressure values are measured, a common time on the display surface of the display unit Display control means for displaying a graph along an axis.