JPH0675406U - Biological circulation display - Google Patents

Abstract

(57) [Summary] (Modified) [Objective] To provide a circulatory dynamics display device of a living body which can predict a change in the blood pressure value of the living body or can estimate the cause of the change in the blood pressure value. A device for displaying the circulatory dynamics of a living body, a blood pressure determining means 50 for continuously determining a blood pressure value of the living body, and a pulse wave sensor 46 for detecting a pulse wave generated from an artery of the living body.
A waveform analysis value determining means 52 for continuously determining a waveform analysis value indicating the characteristics of the waveform of the pulse wave detected by the pulse wave sensor; a display 38 capable of displaying a graph; A display control means 54 for displaying in parallel a graph showing a blood pressure value and a graph showing a continuously determined waveform analysis value on a common time axis in a display device. Circulatory dynamics display device.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a device for displaying circulatory dynamics of a living body.

[0002]

[Prior art]

 For example, in a living body under general anesthesia, it is desired to accurately grasp its circulatory dynamics. On the other hand, conventionally, the blood pressure value is often used as a value representing the circulatory dynamics of a living body.

[0003]

[Issues to be solved by the device]

 However, since the blood pressure value is determined by the blood output of the heart and the peripheral resistance of blood vessels, for example, when a sudden decrease in blood pressure value is recognized, it is likely that the basic organs such as the cranial nerve and the heart will be affected. As the actual blood flow rate began to decline, medical treatment tended to be delayed. In addition, for example, when a decrease in blood pressure occurs, it is unclear whether the cause is weakened cardiac output, or whether blood vessels have opened and peripheral resistance has decreased. Such choices tended to be relatively difficult.

As a result of various studies on the present invention against the background described above, the shape of the pulse wave generated from the artery of the living body includes various information indicating the circulatory dynamics of blood. It was found that the analysis value of the shape appears prior to the actual change of the blood pressure value, and that the cardiac output state and the relaxation state of peripheral blood vessels, which are the elements that constitute the blood pressure value, can be grasped.

The present invention has been made on the basis of such knowledge, and its purpose is to predict the change in the blood pressure value of the living body or to estimate the cause of the change in the blood pressure value of the living body. An object is to provide a circulatory dynamics display device.

[0006]

[Means for Solving the Problems] A gist of the present invention for achieving the above object is a device for displaying the circulatory dynamics of a living body, comprising: (a) continuously measuring the blood pressure value of the living body. Blood pressure determining means that determines the pulse wave, and (b) a pulse wave sensor that detects the pulse wave generated from the artery of the living body, and (c) a waveform analysis that shows the characteristics of the waveform of the pulse wave detected by the pulse wave sensor. A waveform analysis value determining means for continuously determining the value, (d) a display capable of displaying a graph, (e) a graph showing the continuously determined blood pressure value, and the continuously determined And a display control means for displaying the graph showing the waveform analysis value in parallel on the common time axis in the display.

[0007]

[Action]

 In this way, the graph showing the blood pressure value continuously determined by the blood pressure determining means and the graph showing the waveform analysis value continuously determined by the waveform analysis value determining means are displayed by the display control means. In parallel, they can be displayed in parallel on the common time axis.

[0008]

[Effect of the first device] The waveform analysis value showing the characteristics of the waveform of the pulse wave appears prior to the actual change of the blood pressure value, and at the same time, the cardiac side output state and peripheral blood vessels, which are the constituent elements of the blood pressure value. Since it shows the relaxation state, the change can be easily grasped by comparing the graph showing the waveform analysis value displayed on the display with the graph showing the blood pressure value displayed in parallel with it. Changes in blood pressure can be predicted based on changes in analysis values. Also, when the blood pressure value changes according to the change in the waveform analysis value, it is possible to easily understand whether the cause of the blood pressure change is the heart side or the peripheral blood vessel, depending on the type of the waveform analysis value. The choice of drugs used in medical treatment becomes precise.

[0009]

A second aspect of the present invention to achieve the above object is to provide a device for displaying the circulatory dynamics of a living body, comprising: (a) Blood pressure determining means for continuously determining the blood pressure value of the living body, (b) a pulse wave sensor for detecting a pulse wave generated from the artery of the living body, (c) a pulse wave detected by the pulse wave sensor From the waveform of, the waveform analysis value determining means for continuously determining the waveform analysis value showing the characteristics of the waveform, and (d) the difference value between the blood pressure value and the waveform analysis value determined at the same time is continuously determined. A difference value calculating means for calculating, (e) a display device capable of displaying a graph, and (f) a display control means for displaying a graph showing the difference value on a predetermined time axis of the display device. is there.

[0010]

[Action]

 With this configuration, the difference value between the blood pressure value continuously determined by the blood pressure determination means and the waveform analysis value continuously determined by the waveform analysis value determination means is calculated by the difference value calculation means, and the display control is performed. By the means, a graph showing the difference value is displayed on a predetermined time axis of the display.

[0011]

[Effect of the second device] The waveform analysis value showing the characteristics of the waveform of the pulse wave appears prior to the actual change of the blood pressure value, and the cardiac side output state and the peripheral blood vessels that are the elements that constitute the blood pressure value. The change in the blood pressure value can be easily estimated by observing the difference value displayed on the display, since the change in the blood pressure value can be easily recognized. it can. In that case, it is possible to easily understand whether the cause of blood pressure change is on the cardiac side or the peripheral blood vessel, depending on the type of waveform analysis value, and the drug used for medical treatment can be selected. It will be accurate.

[0012] Preferably, the waveform analysis value determining means is a slope value calculating means for obtaining a slope value which is a maximum slope value at a rising portion of the pulse wave, and the pulse of the average value of the pulse wave. % MAP value calculating means for obtaining a% MAP value which is a ratio to the maximum amplitude value of the wave, CR value calculating means for obtaining a CR value which is a time constant at the falling portion of the pulse wave, amplitude of swell of continuous pulse wave It includes at least one of the swell amplitude calculating means for obtaining

[0013]

【Example】

 Hereinafter, a circulatory dynamic display device according to an embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a cuff 10 wrapped around an upper arm of a living body is compressed into a bag shape by an elastic film such as a rubber sheet or a vinyl sheet. The pump 14 and the exhaust control valve 16 are connected to each other via an air pipe 18.

The pressure sensor 12 includes, for example, a semiconductor pressure detecting element, detects the pressure in the cuff 10, and outputs a pressure signal SP representing the pressure to the low pass filter 20, the first band pass filter 22, It is supplied to the second bandpass filter 23. The low-pass filter 20 discriminates a DC component contained in the pressure signal SP to extract a static pressure, and outputs it as a cuff pressure signal SK to the A / D converter 24. Further, the first bandpass filter 22 discriminates the frequency component of, for example, 1 to 10 Hz included in the pressure signal SP and extracts the pulse wave component, and outputs the pulse wave signal SM1 to the A / D converter 24. . In the cuff 10 wound around the upper arm of the living body, pressure fluctuations are generated in synchronization with the heartbeat based on the pulsation of the artery.

The second bandpass filter 23 discriminates a frequency component of 0.5 to 20 Hz contained in the pressure signal SP to extract a pulse wave component, and outputs the pulse wave signal SM2 to the A / D converter 24. To do. The first bandpass filter 22 has a narrow frequency characteristic for extracting the pulse wave amplitude without the influence of noise such as motion artifact noise, whereas the second bandpass filter 23 has an arterial characteristic. It has a relatively wide frequency characteristic for the purpose of accurately extracting from the cuff 10 a pulse wave having the same shape as the pressure pulse wave generated inside. The A / D converter 24 includes a multiplexer that time-divisions the three types of input signals, and has a function of A / D converting the three types of input signals in parallel. .

The arithmetic and control unit 26 is a so-called microcomputer including a CPU 28, a RAM 30, a ROM 32, an output interface 34, and a display interface 36. The CPU 28 receives the signal input from the A / D converter 24 from the RAM 30. While using the temporary storage function of the above, processing is performed in accordance with a program stored in advance in the ROM 32, the air pump 14 and the exhaust control valve 16 are driven and controlled via the output interface 34, and the display interface 36 is used to display. Drive control of 38. The display 38 has an image display plate capable of displaying numerical values and waveforms by a large number of light emitting elements.

The mode changeover switch 40 is operated to switch between the blood pressure measurement mode and the waveform analysis value display mode, and selectively outputs a signal instructing the blood pressure measurement mode or the waveform analysis value display mode to the CPU 28. Supply to. The start / stop switch 42 supplies the CPU 28 with a signal for alternately instructing start and stop for each pressing operation. Further, in order to detect the pressure pulse wave generated in the radial artery or the dorsalis pedis artery, the pulse wave sensor 46 is attached to the wrist or foot while being pressed by the artery, and the pulse wave component is discriminated from the output signal thereof. And a third bandpass filter 48 for controlling the frequency. This pulse wave sensor 46 is, for example, a semiconductor in which a plurality of pressure detection elements are arranged on the pressing surface, as in the one disclosed in Japanese Patent Publication No. 4-67839 previously filed and published by the present applicant. It has a pressure sensor.

FIG. 2 and FIG. 3 are functional block diagrams respectively explaining the main parts of the control operation of the arithmetic and control unit 26. In FIG. 2, the pulse wave sensor 46 detects the pulse wave generated from the artery of the living body in synchronization with the heartbeat. The blood pressure determining means 50 continuously determines the blood pressure value of the living body. For example, in the process of continuously determining the blood pressure value of the living body based on the magnitude of the actual pulse wave detected by the pulse wave sensor 46 from a preset relationship, or changing the compression pressure by the cuff 10. The blood pressure determination cycle for determining the blood pressure value based on the obtained change in the amplitude value of the pressure oscillation of the cuff is repeatedly executed to continuously measure the blood pressure value. The waveform analysis value determination means 52 continuously calculates the waveform analysis value indicating the local characteristics of the waveform of the pulse wave of the living body detected by the pulse wave sensor 46 according to a predetermined calculation formula. The waveform analysis value is, for example, a slope value SLOPE related to the slope of the rising portion of the pulse wave, a% MAP value or a time constant value CR related to the slope of the falling portion of the pulse wave. The display control means 54 causes the graph of the blood pressure value and the graph of the waveform analysis value to be displayed in parallel on the screen of the display 38 on a common time axis.

Also in FIG. 3, similarly to the above, the pulse wave sensor 46 detects the pulse wave generated from the artery of the living body in synchronization with the heartbeat. The blood pressure determining means 50 continuously determines the blood pressure value of the living body. For example, in the process of continuously determining the blood pressure value of the living body based on the magnitude of the actual pulse wave detected by the pulse wave sensor 46 from a preset relationship, or changing the compression pressure by the cuff 10. The blood pressure determination cycle for determining the blood pressure value based on the obtained change in the amplitude value of the pressure oscillation of the cuff is repeatedly executed to continuously measure the blood pressure value. The waveform analysis value determination means 52 continuously calculates the waveform analysis value indicating the local characteristics of the waveform of the pulse wave of the living body detected by the pulse wave sensor 46 according to a predetermined calculation formula. The difference value calculation means 56 calculates the difference between the blood pressure value and the waveform analysis value, and the display control means 54 causes the screen of the display 38 to display a graph showing the difference value on a predetermined time axis.

FIG. 4 is a flow chart for explaining a main part of the control operation of the arithmetic and control unit 26. When it is determined in a step (not shown) whether the device has been activated based on the signal from the activation / stop switch 42, in step S1, an oscillometric blood pressure measurement routine using the cuff 10 is executed. It is executed to determine the blood pressure value. In this blood pressure measurement routine, according to a well-known blood pressure measurement procedure, the pressure of the cuff 10 is raised to a predetermined target pressure, and then the compression pressure of the cuff 10 is gradually lowered at a rate of, for example, 2 to 3 mmHg / sec. The cuff pressure at the time when the amplitude of the pressure oscillation of the cuff suddenly changes is determined as the systolic blood pressure value SAP and the diastolic blood pressure value DAP.

In the subsequent step S2, the maximum peak value and the minimum peak value of the pulse wave detected by the pulse wave sensor 46 when the systolic blood pressure value SAP and the diastolic blood pressure value DAP are determined are determined, and those maximum values are determined. By associating the high blood pressure value SAP and the lowest blood pressure value DAP with the highest peak value and the lowest peak value, the correspondence relationship between the blood pressure value BP and the pulse wave value (magnitude) AMP is determined as shown in Expression 1.

[0023]

[Equation 1] BP = A / AMP + B

In subsequent step S3, it is determined whether or not one pulse wave detected by the pulse wave sensor 46 is input. When this step S3 is denied, it is made to wait until one pulse wave is input, but when it is affirmed, it is actually input from the formula 1 in step S4 corresponding to the blood pressure determining means 50. The systolic blood pressure value SAP and the diastolic blood pressure value D AP are calculated based on the maximum and minimum peak values of one pulse wave.

Subsequently, in step S5 corresponding to the waveform analysis value determination means 52, a waveform analysis value representing a local feature of the shape of the one pulse wave is calculated. For example, a slope value SLOPE related to the slope of the rising portion of the pulse wave, a% MAP value or a time constant value CR related to the slope of the falling portion of the pulse wave. The slope value SLOPE is defined as the maximum value (dp / dt) _max of the differential value (slope) of the rising portion of the pulse wave. This (dp / dt) _max is proportional to the strength of the myocardium and is a value related to cardiac output. As shown in FIG. 5, the% MAP value is the height of the average blood pressure value MAP (the center of gravity of the pulse wave area) with respect to the amplitude value b in the input pulse wave, that is, the pulse pressure (= SAP-DAP). It is defined as the ratio of a (= MAP-DAP) (= 100 × a / b). In the pulse wave generated from an artery, the falling period is larger than the rising portion, and since this falling period is closely related to the relaxation state of the blood vessel, the above% MAP value is also the relaxation state of the blood vessel. This% MAP value is related to the relaxation state of blood vessels, that is, peripheral resistance.

Next, in step S6 corresponding to the difference value calculating means 56, the difference value DSS (= SAP-SLOPE) between the systolic blood pressure value SAP and the slope value SLOPE, and the systolic blood pressure value SAP and the% MAP value. And the difference value DSM (= SAP-% MAP) is calculated. The difference value DSS and the difference value DSM are for clearly displaying the relative change of the slope value SL OPE and the% MAP value with respect to the systolic blood pressure value SAP.

Next, in step S7 corresponding to the display control means 54, as shown in the display screen of the display 38 of FIG. 6, a graph 62 showing the systolic blood pressure value SAP on the common time axis 60, a slope. A graph 64 showing the value SLOPE, a graph 66 showing the% MAP value, a graph 68 showing the difference value DSS, and a graph 70 showing the difference value DSM are displayed.

In the following step S8, it is determined whether or not the relationship shown in the mathematical expression 1 needs to be updated. This update is based on whether the time elapsed since the relational expression was determined in step S2 has become equal to or longer than the preset time, or whether the blood pressure value determined in step S4 has changed abnormally. It is judged based on. If the determination in step S8 is affirmative, steps S1 and onward are executed again. However, if the determination in step S8 is negative, it is determined in step S9 whether or not the stop operation has been performed by the start / stop switch 42.

When the determination in step S9 is negative, steps S3 and thereafter are repeatedly executed to further obtain the systolic blood pressure value SAP, the slope value SLOPE, the% MAP value, the difference value D SS, and the difference value DSM. A graph 62 showing the systolic blood pressure value SAP, a graph 64 showing the slope value SLOPE, a graph 66 showing the% MAP value, a graph 68 showing the difference value DSS, and a difference value DSM are displayed on the display screen of the display 38. Each graph 70 is further extended. However, if the determination in step S9 is positive, this routine is ended.

As described above, according to the present embodiment, the graph 62 showing the systolic blood pressure value SAP continuously determined by the blood pressure determining means 50 and the slope value continuously determined by the waveform analysis value determining means 52. Graphs 64 and 66 showing the SLOPE and the% MAP value are displayed by the display control means 54 in parallel on the common time axis 60 on the display 38. The above-mentioned slope values SLOPE and% MAP value showing the local characteristics of the waveform of the pulse wave appear prior to the actual change of the systolic blood pressure value SAP, and the cardiac output state which is a factor that determines the systolic blood pressure value SAP. Also, since the relaxation state of the peripheral blood vessels is shown, the slope values SLOPE and the% MAP values displayed on the display 38 are compared with the graphs 62 and 62 showing the systolic blood pressure value SAP which are displayed in parallel therewith. Since the change can be easily grasped, the change in blood pressure value can be predicted based on the change in the slope value SLOPE and the% MAP value. When the systolic blood pressure value SAP changes in response to changes in the slope value SLOPE and% MAP value, the cause of the change in the systolic blood pressure value SAP is based on the changed slope value SLOPE or% MAP value. It is possible to easily understand whether the drug is in the visceral side or in the peripheral blood vessel, and the drug used for medical treatment can be selected accurately.

In addition, according to the present embodiment, the systolic blood pressure value SAP continuously determined in step S 4 corresponding to the blood pressure determination means 50 and the slope value continuously determined by the waveform analysis value determination means 52. The difference value DSS and the difference value DSM from the SLOPE and the% MAP value are calculated by the difference value calculating means 56, and the display control means 54 displays graphs 68 and 70 showing the difference value DSS and the difference value DSM of the display 38. It is displayed on a predetermined time axis. Therefore, by looking at the graphs 68 and 70 showing the difference value DSS and the difference value DSM, it is possible to easily recognize the preceding change with respect to the systolic blood pressure value SAP, so that the change in the systolic blood pressure value SAP can be easily estimated. You can Also, similar to the above, based on the type of slope value SLOPE or% MAP value where the change occurs, it is possible to easily understand whether the cause of the blood pressure change is the cardiac side or the peripheral blood vessel, The drug used for medical treatment can be selected appropriately.

That is, the blood pressure value is determined by the output of the heart and the relaxation state of peripheral blood vessels. On the other hand, catecholamines, which enhance cardiac function, and efotil, which contracts blood vessels, are used as drugs for increasing blood pressure. With the display 38 of the present embodiment, it is possible to ascertain whether the change in blood pressure is caused by the cardiac function or the blood vessel, and therefore the drug acting on the heart function or the drug acting on the blood vessel can be selected accurately. Of.

In step S5 of the above-described embodiment, the SLOPE value and the% MAP value are obtained, and in step S6, the difference values DSS and DSM between them and the systolic blood pressure value SAP are obtained, which are displayed on the display 38. However, as another example of the pulse wave analysis value, the size of the swell of the pulse wave as shown in FIG. 7, for example, the amplitude SPV of the envelope connecting the systolic blood points is obtained in step S5, and its amplitude SPV The difference value DSA from the systolic blood pressure value SAP may be obtained in step S6 and displayed on the display 38. This amplitude SPV corresponds to the circulating amount of body fluid (blood), and may be the amplitude of the envelope connecting the lowest blood pressure points or the amplitude of the envelope connecting the average blood pressure points.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other aspects.

For example, in step S4 corresponding to the blood pressure determining means 50 in the above-described embodiment, the blood pressure values SAP and DAP were determined based on the actual pulse wave value from Equation 1, but this will be described in step S1. The blood pressure measurement may be repeated.

Further, in step S5 corresponding to the waveform analysis value determining means 52 of the above-mentioned embodiment,% MAP was used as the waveform analysis value indicating the relaxation state of the blood vessel or the peripheral resistance. The constant value CR may be obtained and displayed as a graph. When the falling curve of the input pulse wave is viewed as a first-order lag curve, the degree of curve can be expressed by the time constant value of the first-order lag curve. It can be obtained by determining the first-order lag curve that approximates the curve of the period and determining the time constant value. This time constant value CR is also a value related to the relaxation state of blood vessels, that is, peripheral resistance in relation to the shape of the falling period of the pulse wave.

Further, in the above-described embodiment, the pulse wave generated from the artery is detected by the pulse wave sensor 46, but instead of this, the pulse wave may be collected from the cuff 10. In this case, the pressure of the cuff 10 is kept near the average blood pressure value MAP by the exhaust control valve 16, and the pressure sensor 12 detects the pressure vibration generated in the cuff 10 in this state in synchronization with the heartbeat. , A relatively undistorted pulse wave is obtained. In this case, the pulse wave sensor 46 becomes unnecessary, and the cuff 10, the pressure sensor 12 and the like constitute pulse wave detecting means.

In the display 38 of the above-described embodiment, the graph 62 showing the systolic blood pressure value SAP is arranged in parallel with the graph 64 showing the slope value SLOPE and the graph 66 showing the% MAP value on the common time axis 60. Although it is displayed, even if one of the graph 64 showing the slope value SLOPE and the graph 66 showing the% MAP value is displayed in parallel with the blood pressure value SAP, the same effect as that of the above-described embodiment is temporarily obtained.

In the display 38 of the above-described embodiment, the graph 68 showing the difference value DSS and the graph 70 showing the difference value DSM are displayed on the time axis 60, but the graph 68 showing the difference value DSS. Even if one of the graphs 70 showing the difference value DSM and the difference value DSM is displayed, the same effect as that of the above-described embodiment can be obtained.

Further, in the above-described embodiment, the graph 62 showing the systolic blood pressure value SAP as the blood pressure value is configured to be displayed on the display device 38. However, instead of this, the mean blood pressure value MAP or the diastolic blood pressure value is displayed. It may be configured to display a graph showing the value DAP.

The above description is merely an example of the present invention, and the present invention can be modified in various ways without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating the configuration of an embodiment of the present invention.

2 is a functional block diagram illustrating a first main part of a control function of an arithmetic control circuit 26 of FIG.

FIG. 3 is a functional block diagram illustrating a second main part of the control function of the arithmetic control circuit 26 of FIG.

4 is a flowchart illustrating a main part of a control operation of an arithmetic control circuit 26 of FIG.

5 is a diagram illustrating% MAP determined in FIG. 4. FIG.

6 is a diagram illustrating in detail an example of a graph displayed on the display of FIG. 1 by the control operation of FIG.

FIG. 7 is a diagram illustrating an amplitude SPV of a swell of a pulse wave which is a pulse wave analysis value in another embodiment of the present invention.

[Explanation of symbols]

 10: Cuff, 12: Pressure sensor (pulse wave sensor) 38: Display 46: Pulse wave sensor 50: Blood pressure determination means 52: Waveform analysis value determination means 54: Display control means 56: Difference value calculation means

Claims (2)

[Scope of utility model registration request] 1. A device for displaying circulatory dynamics of a living body, comprising: a blood pressure determining means for continuously determining a blood pressure value of the living body; a pulse wave sensor for detecting a pulse wave generated from an artery of the living body; Waveform analysis value determining means for continuously determining the waveform analysis value indicating the characteristics of the waveform of the pulse wave detected by the pulse wave sensor, a display capable of displaying a graph, and the continuously determined blood pressure value A circulatory dynamics of a living body, comprising: a display control means for displaying the graph shown and the graph showing the continuously determined waveform analysis value in parallel on a common time axis in the display. Display device. 2. A device for displaying the circulatory dynamics of a living body, comprising a blood pressure determining means for continuously determining the blood pressure value of the living body, and a pulse wave sensor for detecting a pulse wave generated from an artery of the living body. A waveform analysis value determining means for continuously determining a waveform analysis value indicating the characteristics of the waveform of the pulse wave detected by the pulse wave sensor, and a difference value between the blood pressure value and the waveform analysis value determined at the same time. It is characterized by including a difference value calculating means for continuously calculating, a display device capable of displaying a graph, and a display control means for displaying a graph showing the difference value on a predetermined time axis of the display device. Circulatory dynamics display device for living body.