JP3595593B2 - Blood ejection function evaluation device - Google Patents

Description

[0001]
[Industrial applications]
TECHNICAL FIELD The present invention relates to a blood ejection function evaluation device for evaluating a blood ejection function of a living body heart.
[0002]
[Prior art]
The blood ejection function of the heart of a living body increases in accordance with the exercise load applied to the living body, and has a property of recovering toward a resting state when the exercise load is removed. For example, since the blood ejection volume of the heart is determined by the stroke volume per stroke SV (Stroke Volume) × heart rate HR (Heart Rate), the above-mentioned stroke volume is assumed on the assumption that peripheral resistance does not change so much. The blood pressure value reflecting the SV is measured before and after the exercise load is applied, and the change in the blood pressure before and after the exercise load is applied and the recovery state after the exercise load is applied are estimated to estimate the blood ejection function of the heart and the presence or absence of a disease. Can be used as reference data.
[0003]
Further, the magnitude of the pressure pulse wave generated from the artery is calibrated based on the actual blood pressure value, and the blood pressure value for each beat is measured before and after the exercise load is applied, and the blood pressure value for each beat is measured before and after the exercise load is applied. The index of the area during the ejection period of the pressure pulse wave using the change state of the pressure pulse wave or utilizing the fact that the area of the ejection period of the pressure pulse wave calibrated to the blood pressure value reflects the stroke amount SV. It has been proposed to use the change or recovery state of the value as reference data for estimating the blood ejection function of the heart or the presence or absence of a disease.
[0004]
[Problems to be solved by the invention]
However, as described above, in order to evaluate the blood ejection function of the heart of a living body by applying an exercise load to the living body, the blood pressure value of the living body before and after the exercise load is measured using a cuff that compresses a part of the living body. It has been relatively difficult to accurately measure blood pressure especially after exertion of an exercise load in a blood ejection function evaluation apparatus of the type that measures the blood ejection function. In other words, immediately after the exercise load of the living body is applied, the respiration of the living body is often disturbed compared to the resting state, and it is inevitable that the body movement due to the respiration affects the blood pressure measurement as noise. is there. For this reason, there was a drawback that the accuracy of evaluating the blood ejection function of the heart was not sufficiently obtained. One of the objectives of the evaluation of the blood ejection function of the heart is to diagnose, for example, what is called painless myocardial ischemia (Silent Myocardial Ischemia). It is hoped that high evaluations will be possible.
[0005]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a blood ejection function evaluation device that can accurately evaluate the blood ejection function of the heart.
[0006]
[Means for Solving the Problems]
The gist of the present invention to achieve the above object is to use a cuff that compresses a part of the living body in order to evaluate the blood ejection function of the heart of the living body by applying exercise load to the living body. A blood ejection function evaluation device of the type for measuring the blood pressure value of a living body before and after exercise load application, respectively (a) provided on the peripheral side and the trunk side of the cuff, on the peripheral side and the trunk side of the cuff A peripheral microphone and a trunk microphone that respectively detect a generated pulse sound, and (b) the trunk microphone of the peripheral pulse sound detected on the distal side of the cuff by the peripheral microphone on the trunk side of the cuff. Delay time determining means for determining a delay time with respect to the detected fundamental pulse sound, (c) the magnitude of the peripheral pulse sound detected by the peripheral microphone and the delay A blood pressure evaluation curve calculating means for sequentially calculating a product of the pressure and the pressure of the cuff according to a change in the pressure of the cuff to obtain a blood pressure evaluation curve that changes along an axis indicating the pressure of the cuff; Blood pressure value determination for detecting a sharp rising point and a falling point of the blood pressure evaluation curve obtained by the curve calculating means and determining the cuff pressure corresponding to the rising point and the falling point as a systolic blood pressure value and a diastolic blood pressure value. Means,(e) A pressure pulse wave sensor attached to the living body to detect a pressure pulse wave generated in synchronization with a heartbeat from the artery of the living body, (f) First index value determining means for determining a first index value corresponding to the systolic area of the shape of the pressure pulse wave detected by the pressure pulse wave sensor before the exercise load is applied to the living body; (g) Second index value determining means for determining a second index value corresponding to the systolic area of the shape of the pressure pulse wave detected by the pressure pulse wave sensor after the exercise load is applied to the living body, (h) Evaluation means for evaluating the blood ejection function of the heart based on a change between the first index value and the second index value;Is to include.
[0007]
[Action]
According to this configuration, the delay time determining unit delays the peripheral pulse sound detected on the distal side of the cuff by the peripheral microphone with respect to the core pulse sound detected on the trunk side of the cuff by the trunk microphone. When the time is determined, by the blood pressure evaluation curve calculating means, by sequentially calculating the product of the magnitude of the peripheral pulse sound detected by the peripheral microphone and the delay time according to the change in the pressure of the cuff, A blood pressure evaluation curve that varies along an axis indicating the pressure of the cuff is determined. Then, the blood pressure value determining means detects a sharp rising point and a falling point of the blood pressure evaluation curve, and the cuff pressures corresponding to the rising point and the falling point are determined as the systolic blood pressure value and the diastolic blood pressure value, respectively. .
[0008]
【The invention's effect】
In the blood pressure evaluation curve, the sharp rising point and the falling point are emphasized by multiplying the loudness of the peripheral pulse sound and the delay time, so that the influence of noise due to body movement or the like is greatly increased. Since the blood pressure is removed, higher measurement accuracy can be obtained as compared with the conventional blood pressure determination by the Korotkoff sound method or the oscillometric method. Therefore, in order to evaluate the blood ejection function of the heart of a living body by applying an exercise load, a blood ejection function evaluation device of a type that measures the blood pressure value before and after the exercise load is applied to the blood ejection function of the living body Can be accurately evaluated. In addition, the diagnostic accuracy of painless myocardial ischemia can be improved.In addition, since the ejection function of the heart is evaluated based on the change in the first index value and the second index value corresponding to the systolic area of each pulse wave shape before and after the exercise load is applied, the blood is more accurately measured. Ejection function can be evaluated. In addition, accurate evaluation of the blood ejection function enables diagnosis of painless myocardial ischemia.
[0011]
Other aspects of the invention
SuitableThe evaluation means may determine whether the amount of change or the rate of change between the first index value and the second index value exceeds a predetermined criterion value. Is determined. With this configuration, it is only necessary to determine whether or not the amount of change or the rate of change between the first index value and the second index value has exceeded the determination reference value, so that a complicated determination algorithm is not required. There is.
[0012]
Further, preferably, the evaluation means determines the blood ejection function of the heart based on a recovery time or a recovery rate for recovering toward the first index value of the second index value. With this configuration, since the evaluation is performed based on the recovery state that recovers toward the first index value of the second index value, the evaluation of the blood ejection function becomes more accurate.
[0013]
Preferably, the pressure pulse wave detected by the pressure pulse wave sensor is converted into the aorta based on a pulse wave signal transmission function between a portion where the pressure pulse wave sensor is mounted and the aorta of the living body. Waveform conversion means for converting the waveform into the above waveform is further included. With this configuration, the first index value and the second index value are more accurately determined using the waveform in the aorta, and there is an advantage that the evaluation accuracy of the blood ejection function is improved.
[0014]
Preferably, a blood pressure measuring means for measuring a blood pressure value of the living body using a cuff, and a size of a pressure pulse wave detected by the pressure pulse wave sensor before and after the exercise load is applied to the living body. And the blood pressure value measured by the blood pressure measurement means, the correspondence between the pressure pulse wave and the blood pressure value of the living body is determined in advance, and the pressure pulse wave sensor uses the correspondence to determine the correspondence. Pressure pulse wave calibration means for calibrating the detected pressure pulse wave is further included. With this configuration, the pressure pulse wave is calibrated into a waveform representing the blood pressure value of the living body before and after the exercise load is applied to the living body, and thus is generated before and after the exercise load of the first index value and the second index value. There is an advantage that the relative difference is eliminated and the evaluation accuracy of the blood ejection function is further enhanced.
[0015]
【Example】
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a blood ejection function evaluation device 8 to which the present invention has been applied.
[0016]
In FIG. 1, a blood ejection function evaluation device 8 includes a cuff 10 having a rubber bag in a cloth band-shaped bag and wound around, for example, an upper arm 12 of a patient, and a cuff 10 connected to the cuff 10 via a pipe 20. It has a pressure sensor 14, a switching valve 16, and an air pump 18 connected thereto. The switching valve 16 has three states: a rapid pressure rising state in which the supply of the pressure into the cuff 10 is permitted, a slow pressure falling state in which the pressure in the cuff 10 is gradually reduced, and a rapid pressure reducing state in which the pressure in the cuff 10 is rapidly reduced. It is configured to be able to switch to the state.
[0017]
On the trunk side and the distal side of the cuff 10, there are a trunk side microphone 10a and a peripheral side which respectively detect a fundamental pulse sound generated from a proximal artery of the cuff 10 and a peripheral pulse sound generated from a peripheral artery of the cuff 10. A microphone 10b is provided, and pulse sound signals SSa and SSb output from the trunk side microphone 10a and the peripheral side microphone 10b are supplied to a pulse sound discrimination circuit 22 and further electronically controlled through an A / D converter 26. It is supplied to the device 28. The pulse sound discriminating circuit 22 includes a band pass filter that passes a frequency component constituting a pulse sound.
[0018]
The pressure sensor 14 detects the pressure in the cuff 10 and outputs a pressure signal SP representing the pressure. The pressure signal SP is supplied to a static pressure discrimination circuit 24. The static pressure discriminating circuit 24 includes a low-pass filter, and the stationary pressure included in the pressure signal SP, that is, the cuff pressure P_kIs discriminated, and the cuff pressure signal SK is supplied to the electronic control unit 28 via the A / D converter 30.
[0019]
The electronic control unit 28 includes a so-called microcomputer including a CPU 29, a ROM 31, a RAM 33, and an I / O port (not shown). The CPU 29 performs a storage function of the RAM 33 according to a program stored in the ROM 31 in advance. By executing the signal processing while using it, a drive signal is output from the I / O port to control the switching valve 16 and the air pump 18.
[0020]
The pressure pulse wave detection probe 34 is attached to the upper arm 12 of the patient on the downstream side of the artery to which the cuff 10 is attached, by the wearing band 40 with the open end of the housing 36 having a container shape facing the body surface 38. It is configured to be detachably attached to the wrist 42. Inside the housing 36, a pressure pulse wave sensor 46 is provided via a diaphragm 44 so as to be relatively movable and protrudable from an open end of the housing 36, and a pressure chamber 48 is formed by the housing 36, the diaphragm 44, and the like. Have been. The pressure chamber 48 is supplied with pressurized air from an air pump 50 via a pressure regulating valve 52, so that the optimal pressing force P_HDP, So that the pressure pulse wave sensor 46 applies a pressing force P corresponding to the pressure in the pressure chamber 48._HDIs pressed against the body surface 38.
[0021]
The pressure pulse wave sensor 46 is configured by arranging a large number of semiconductor pressure-sensitive elements (not shown) on a flat pressing surface 54 of a semiconductor chip made of, for example, single crystal silicon. The pressure pulse wave, ie, the pressure pulse wave, generated from the radial artery 56 and transmitted to the body surface 38 by being pressed on the radial artery 56 of FIG. SM₂  Is supplied to the electronic control unit 28 via the A / D converter 58.
[0022]
The CPU 29 of the electronic control unit 28 outputs a drive signal to the air pump 50 and the pressure regulating valve 52 in accordance with a program stored in the ROM 31 in advance, so that the pressure in the pressure chamber 48, that is, the pressure pulse wave sensor 46 is pressed against the skin. Adjust pressure. Thereby, in the continuous pressure pulse wave measurement, the pressure pulse wave for pressing until a part of the tube wall of the radial artery 56 becomes flat based on the pressure pulse wave sequentially obtained in the pressure change process in the pressure chamber 48. Optimal pressing force P of sensor 46_HDPIs determined, and the optimum pressing force P of the pressure pulse wave sensor 46 is determined._HDPIs controlled so as to maintain the pressure.
[0023]
FIG. 2 is a functional block diagram illustrating a main part of a control function of the electronic control device 28 in the blood ejection function evaluation device 8. In the figure, the blood pressure measuring means 60 raises the compression pressure of the cuff 10 to a pressure value set higher than the systolic blood pressure value of the living body, and then gradually reduces the compression pressure of the cuff 10 to about 2 to 3 mmHg / sec. In the process of changing at a high speed, the peripheral pulse sound and the fundamental pulse sound detected respectively by the peripheral microphone 10b and the trunk microphone 10a provided in the cuff 10 are detected, and the peripheral pulse sound and the trunk pulse sound are detected. From the blood pressure evaluation curve L calculated based on the occurrence time difference, ie, the delay time DT of the peripheral pulse sound with respect to the base pulse sound and the magnitude (ie, amplitude value) MA of the peripheral pulse sound._BPSYSAnd diastolic blood pressure P_BPDIAIs measured.
[0024]
For example, the blood pressure measurement means 60 determines the delay time DT of the peripheral pulse sound detected on the distal side of the cuff 10 by the peripheral microphone 10b with respect to the core pulse sound detected on the trunk side of the cuff 10 by the trunk microphone 10a. And the delay time DT obtained by multiplying the product of the magnitude MA of the peripheral pulse sound detected by the peripheral microphone 10b and the delay time DT by the pressure P of the cuff 10 during the slow speed change period._k, The pressure P of the cuff 10 is calculated._kA blood pressure evaluation curve calculation means 62 for obtaining a blood pressure evaluation curve L that changes along an axis indicating, and a sharp rising point and a falling point of the blood pressure evaluation curve L obtained by the blood pressure evaluation curve calculation means 62 are detected; Cuff pressures P corresponding to their rising and falling points_kSYSAnd P_kDIAIs the systolic blood pressure value P_BPSYSAnd diastolic blood pressure P_BPDIAAnd blood pressure value determining means 63 for determining FIG. 3 shows the loudness MA of the peripheral pulse sound, the delay time DT, and the blood pressure evaluation curve L, respectively.
[0025]
The pressure pulse wave sensor 46 detects a pressure pulse wave generated from the radial artery of the wrist by being pressed by a part where the cuff 10 of the patient is worn, for example, a part downstream of the upper arm from the artery, for example, the wrist. The pressure pulse wave calibrating means 64 calculates the upper peak value P of the pressure pulse wave detected by the pressure pulse wave sensor 46, for example._HpkAnd the systolic blood pressure value P measured by the blood pressure measuring means 60_BPSYS, The center of gravity value of the area of the pressure pulse wave detected by the pressure pulse wave sensor 46 and the average blood pressure value P measured by the blood pressure measuring means 60_BPMEAN, The lower peak value P of the pressure pulse wave detected by the pressure pulse wave sensor 46_LpkAnd the diastolic blood pressure value P measured by the blood pressure measuring means 60_BPDIAAt least two points between the pressure pulse wave P_MIs determined before and after a predetermined exercise load is applied to the living body, and the pressure pulse wave detected by the pressure pulse wave sensor 46 is calibrated using the correspondence. . Thus, the calibrated pressure pulse wave shows a blood pressure waveform in the artery. The correspondence is, for example, as shown in FIG._BP= A ・ P_M+ B expression. Here, A is a constant indicating the slope, and B is a constant indicating the intercept.
[0026]
Between the pressure pulse wave sensor 46 and the pressure pulse wave calibration means 64, preferably, the transmission function TF of the pulse wave signal between the site where the pressure pulse wave sensor 46 is mounted and the aorta of the living body is determined. On the basis of this, a waveform converting means 66 for converting the pressure pulse wave detected by the pressure pulse wave sensor 46 into a waveform in the aorta is provided. The pressure pulse wave converted into the waveform in the aorta more clearly shows a rising point, an upper peak point, a notch DN generated in association with aortic valve closure, and the like.
[0027]
A well-known treadmill is used as the exercise load device 68, but another device such as an ergometer may be used. The exercise intensity and the exercise time set in the exercise load device 68 are determined according to the age, physical strength, physical condition, and the like of the subject so that the exercise load increases as long as the safety of the subject can be ensured. .
[0028]
The first index value determining means 70 determines the first index value EV corresponding to the systolic area of the shape of the pressure pulse wave detected by the pressure pulse wave sensor 46 before the exercise load is applied to the living body by the exercise load device 68.₁To determine. This first index value EV₁Defines the characteristic values of the shape of the pressure pulse wave as shown in FIG._dnAnd the pressure value (systolic blood pressure value) P at the upper peak point_HpkRatio P_dn/ P_Hpk, Pressure value P of notch DN_dnAnd lower peak pressure value (diastolic blood pressure) P_LpkRatio P_dn/ P_Lpk, Pressure value P of notch DN_dnAnd pulse pressure PP (= P_Hpk-P_Lpk) And the ratio P_dn/ PP, pulse pressure PP and lower peak point pressure value P_LpkRatio PP / P_LpkOr a time interval PEP (pre-ejection period) from the Q wave of the electrocardiographic waveform to the rising point of the pressure pulse wave and the cutoff from the rising point of the pressure pulse wave. Ratio PEP / ET to ejection period ET (= LVET: Left Venticular Ejection Time) to mark DN, time interval T from rising point of pressure pulse wave to upper peak point_pkAnd the ratio T of the ejection period ET_pk/ ET, maximum value of rising slope of pressure pulse wave (dP / dt)_maxEtc. may be selected from the second group.
[0029]
Since the systolic area of the pressure pulse wave shown by oblique lines in FIG. 5 is considered to be proportional to the stroke volume SV (Stroke Volume) of the heart, the pressure value P at the lower peak point is obtained._LpkPressure value P of notch DN_dnThe index value EV of the first group is set to indicate the systolic area using an index of how high is the index. Further, as the ejection period ET is shorter, the pressure value P at the upper peak point is smaller._HpkIs considered not to rise, the index value EV of the second group is set to indicate the systolic area using an index of how long the ejection period ET is. In any case, the index values of the first group and the second group correspond to the systolic area in the form of the pressure pulse wave, and indirectly represent the actual stroke volume SV of the heart. .
[0030]
The second index value determining means 72 determines the second index value EV corresponding to the systolic area of the pulse wave shape detected by the pressure pulse wave sensor 46 after the exercise load is applied to the living body by the exercise load device 68.₂To determine. This second index value EV₂Is the first index value EV₁And is selected from the first group or the second group.
[0031]
The evaluation means 74 determines the first index value EV determined by the first index value determination means 70.₁And the second index value EV determined by the second index value determining means 72₂And evaluate the heart's blood ejection function based on changes. For example, the evaluation means 74 calculates the first index value EV₁And the second index value EV₂ΔEV (= EV)₁-EV₂) Or change rate EV₁/ EV₂Is determined based on whether or not exceeds a predetermined criterion value. Alternatively, the evaluation means 74 determines that the second index value EV₂First index value EV of₁Recovery time TR or recovery rate ΔEV per unit time₂Is used to determine the blood ejection function of the heart.
[0032]
The display means 76 displays the second index value EV determined by the second index value determination means 72.₂Is the first index value EV determined by the first index value determining means 70.₁Is displayed on the display unit 32 in comparison with. 6 to 8 show examples of the display. In FIG. 6, the first index value EV₁Index value EV when is 100%₂Is displayed in the form of a pie chart. Here, the second index value EV₂Is the first index value EV indicated as 100%₁Has been contrasted. In FIG. 7, the second index value EV₂First index value EV of₁EV relative to₂/ EV₁(%) Is trend-displayed as a change with the lapse of time after the end of exercise load application. Here, the above ratio EV₂/ EV₁(%) Is EV displayed as 100%₂/ EV₁(EV₁= EV₂). In FIG. 8, the systolic blood pressure value P_SYSThe amplitudes of the S and T waves of the electrocardiographic waveform, the heart rate HR, and the absolute value of the index value EV of the pressure pulse wave are displayed on each of the four axes, and the display points of the axes are connected by straight lines. ing. The solid line in FIG. 8 indicates a value before the exercise load is applied, and the broken line indicates a value after the exercise load is applied. Here, the index value EV after the exercise load is applied₂Is the index value EV before exercise load application₁Is displayed in contrast to. 6 to 8 show a case where the blood ejection function is reduced.
[0033]
FIG. 9 is a flowchart illustrating a main part of the control operation of the electronic control device 28. In step SA1 of FIG. 9 (hereinafter, the steps are omitted), it is determined whether or not the activation operation of the blood ejection function evaluating device 8 is performed by an operation button (not shown). If the determination in SA1 is denied, the process is suspended. If the determination is affirmed, the blood pressure measurement routine by the cuff 10 is executed in SA2 corresponding to the blood pressure measurement means 60. Time point A in FIG. 10 indicates this state.
[0034]
FIG. 11 is a diagram for explaining the blood pressure measurement routine in detail. In the figure, after the air pump 18 is activated in SA2-1, the switching valve 16 is switched to the rapid pressure increasing side, and the cuff 10 is rapidly increased in pressure. Then, in SA2-2, the pressure P of the cuff 10 is increased._kIs a preset boost target value P₁Is determined. This boost target value P₁Is preset to a value sufficiently higher than the systolic blood pressure value of the living body (for example, 180 mmHg). When the determination in SA2-2 is denied, the pressure increase of the cuff 10 is continued by repeatedly executing the processing in SA2-1 and the subsequent steps. However, when the determination is affirmative, the air pump 18 is stopped in SA2-3. At the same time, the switching pressure of the cuff 10 is gradually reduced at a speed of about 2 to 3 mmHg / sec by switching the switching valve 16 to the slow down pressure side.
[0035]
Next, in SA2-4, it is determined whether a pulse sound has been input. When the determination at SA2-4 is denied, the above SA2-3 and the subsequent steps are repeatedly executed. When the determination is affirmed, the blood pressure value determination algorithm of SA2-5 to SA2-7 is executed. That is, in SA2-5 corresponding to the delay time determination means 61, the peripheral pulse sound detected on the distal side of the cuff 10 by the peripheral microphone 10b is detected on the trunk side of the cuff 10 by the fundamental microphone 10a. It is calculated by calculating the delay time DT with respect to the fundamental pulse sound, that is, the time difference between the generation of the pulse sound signals SSa and SSb.
[0036]
Next, in SA2-6 corresponding to the blood pressure evaluation curve calculating means 62, the blood pressure evaluation value L (P) which is the product of the magnitude MA of the peripheral pulse sound detected by the peripheral microphone 10b and the delay time DT._k) Is required. Thereby, the pressure P of the cuff 10 during the slow change period of the cuff 10 is obtained._kThe blood pressure evaluation value L (P_k) Are sequentially calculated, so that the blood pressure evaluation value L (P_k) And the pressure P of the cuff 10_kAre sequentially obtained from the blood pressure evaluation curve L that changes along the horizontal axis.
[0037]
Then, in SA2-7 corresponding to the blood pressure value determining means 63, a sharp rising point and a falling point of the blood pressure evaluation curve L are detected, and the cuff pressure P corresponding to the rising point and the falling point is detected._kSYSAnd P_kDIAIs the systolic blood pressure value P_BPSYSAnd diastolic blood pressure P_BPDIAIs determined as
[0038]
In subsequent SA2-8, it is determined whether the measurement of the blood pressure value has been completed. In the state where the blood pressure evaluation curve L has not yet been sufficiently formed, for example, while the cuff 10 is being slowly lowered in pressure, the blood pressure value cannot be determined. Is repeatedly executed. However, while the above steps are repeatedly executed, the systolic blood pressure value P_BPSYSAnd diastolic blood pressure P_BPDIAIs determined, the determination in SA2-8 is affirmative, so that in SA2-9, the switching valve 16 is switched to the quick exhaust pressure state, and the pressure in the cuff 10 is quickly exhausted. Hypertension P_BPSYSAnd diastolic blood pressure P_BPDIAIs stored in a predetermined storage location in the RAM 33 and displayed on the display 32 together with the pulse rate and the like. Time point B in FIG. 10 indicates this state.
[0039]
Returning to FIG. 9, in SA3 corresponding to the pressure pulse wave calibration means 64, the magnitude of the pressure pulse wave from the pressure pulse wave sensor 46 (absolute value, ie, the pressure pulse wave signal SM)₂  ) And the blood pressure value P measured by the cuff 10 measured in SA2._BPSYS, P_BPDIAIs required. That is, one pulse of the pressure pulse wave from the pressure pulse wave sensor 46 is read and the maximum value P of the pressure pulse wave is read._HpkAnd the lowest value P_LpkIs determined, and the maximum value P of the pressure pulse waves is determined._HpkAnd the lowest value P_LpkAnd the systolic blood pressure value P measured by the cuff 10 in SA2_BKSYSAnd mean blood pressure value P_BPMEANOr diastolic blood pressure P_BPDIAAnd the magnitude P of the pressure pulse wave shown in FIG._MAnd the correspondence between the blood pressure values are determined. Therefore, the pressure pulse wave signal SM read thereafter₂  Is calibrated by the above-mentioned correspondence, and is made into a waveform indicating the blood pressure value in the artery.
[0040]
When the pressure pulse wave blood pressure correspondence relation is determined as described above, in subsequent SA4, a predetermined number of pressure pulse waves are sequentially read in before the exercise load is applied. Then, in SA5 corresponding to the waveform conversion means 66, the pressure pulse waves sequentially read in SA4 are subjected to waveform conversion processing to restore the waveform in the aorta. For example, in this waveform conversion processing, the pressure pulse wave signal SM is transmitted by a transmission function TF of the pressure pulse wave propagating from the aorta to the site where the pressure pulse wave sensor 46 is mounted.₂  To obtain the pressure pulse wave signal SM₂  Is converted to a waveform in the aorta. The transmission function TF is obtained experimentally in advance using, for example, a catheter inserted into the aorta and the pressure pulse wave sensor 46.
[0041]
Next, at SA6 corresponding to the first index value determining means 70, the first index value EV corresponding to the systolic area of the shape of the pressure pulse wave before the exercise load is applied.₁Is determined. In subsequent SA7, it is determined whether or not the exercise load device 68 has finished applying the exercise load to the living body based on an output signal from the exercise load device 68 or the like. If the determination at SA7 is denied, a permission to exercise the exercise load by the exercise load device 68 is output at SA8. Accordingly, the exercise load device 68 applies an exercise load to the living body based on the preset exercise intensity and exercise time in response to the activation operation by the medical staff. Time point C in FIG. 10 indicates this state.
[0042]
When the exercise load application operation by the exercise load device 68 is completed while the above steps are repeatedly executed, the determination in SA7 is affirmative, and the second index value EV is determined in SA9.₂Is determined. Initially, the determination of SA9 is denied, and the blood pressure measurement by the cuff 10 is started by executing SA2 again. The point D in FIG. 10 indicates the start state of the blood pressure measurement, and the point E indicates the end state. Next, by sequentially executing SA3 to SA5 again, the pressure pulse wave after the exercise load is applied is read and converted into a waveform, and the exercise load is determined in SA6 corresponding to the second index value determination means 72. Index value EV corresponding to the systolic area of the shape of the pressure pulse wave after the₂Is the first index value EV₁Is determined in the same manner as.
[0043]
As described above, the application of the exercise load is completed and the second index value EV₂Is determined, the subsequent determinations of SA7 and SA9 are affirmed. Time point F in FIG. 10 indicates this state. Thereby, in SA10 corresponding to the evaluation means 74, the first index value EV₁And the second index value EV₂The blood ejection function of the heart is evaluated based on the relative change of For example, in SA10, the first index value EV calculated as an average value of a predetermined number of pressure pulse waves before exercise load₁And a second index value EV calculated as an average value of a predetermined number of pressure pulse waves after exercise load₂ΔEV (= EV)₁-EV₂) Or change rate EV₁/ EV₂Is determined to be normal when exceeds a predetermined judgment reference value, but otherwise, it is determined that the blood ejection function of the heart is reduced. Alternatively, in SA10, the second index value EV after the end of the exercise load application₂Is the first index value EV₁When the recovery time TR for recovering toward is shorter than a predetermined reference value, or a recovery rate (inclination value) ΔEV per unit time.₂Is determined to be normal when exceeds a predetermined criterion value, while it is determined that the heart has a reduced blood ejection function in the opposite case. When the blood ejection function of the heart is normal, the systolic area in the form of a pressure pulse wave increases when an exercise load is applied, and the state immediately before the exercise load is applied when the exercise load is completed. Because he recovers towards.
[0044]
Next, in SA11 corresponding to the display means 76, the above-described evaluation result is displayed on the screen of the display 32, and the display illustrated in, for example, FIGS. 6 to 8, that is, the second index value EV after exercise load is displayed.₂Is the first index value EV before exercise load₁And the second index value EV₂First index value EV of₁Is displayed on the display unit 32 so that the change with respect to is easily grasped.
[0045]
As described above, according to the present embodiment, the SA2-5 corresponding to the delay time determining unit 61 uses the trunk microphone 10a to detect the peripheral pulse sound detected on the distal side of the cuff 10 by the peripheral microphone 10b. When the delay time DT with respect to the fundamental pulse sound detected on the trunk side of the cuff 10 is determined, the SA2-6 corresponding to the blood pressure evaluation curve calculation means 62 determines the delay time DT of the peripheral pulse sound detected by the peripheral microphone 10b. By successively calculating the product of the magnitude MA and the delay time DT according to the change in the pressure of the cuff 10, the pressure P of the cuff 10 is calculated._kA blood pressure evaluation curve L that changes along the axis indicating is obtained. Then, at SA2-7 corresponding to the blood pressure value determining means 63, a sharp rising point and a falling point of the blood pressure evaluation curve L are detected, and the cuff pressure P corresponding to the rising point and the falling point is detected._kSYSAnd P_kDIAIs the systolic blood pressure value P_BPSYSAnd diastolic blood pressure P_BPDIARespectively. In the blood pressure evaluation curve L, the sharp rising point and the falling point are emphasized by multiplying the magnitude MA of the peripheral pulse sound by the delay time DT, so that noise caused by body motion or the like is emphasized. Is greatly removed, so that higher measurement accuracy can be obtained as compared with the conventional blood pressure determination by the Korotkoff sound method or the oscillometric method. Therefore, in order to evaluate the blood ejection function of the heart of a living body by applying an exercise load, a blood ejection function evaluation device of a type that measures the blood pressure value before and after the exercise load is applied to the blood ejection function of the living body Can be accurately evaluated. In addition, the diagnostic accuracy of painless myocardial ischemia can be improved.
[0046]
Further, according to the present embodiment, the SA6 corresponding to the first index value determining means 70 determines the systolic area of the pulse wave shape detected by the pressure pulse wave sensor 46 before the exercise load is applied to the living body. Corresponding first index value EV₁Is determined by SA6 corresponding to the second index value determining means 72, and the second corresponding to the systolic area of the pulse wave shape detected by the pressure pulse wave sensor 46 after the exercise load is applied to the living body. Index value EV₂Is determined. Then, the second index value EV is obtained by SA11 corresponding to the display means 76.₂Is the first index value EV₁It is displayed in a state where it is compared with. Therefore, the second index value EV₂First index value EV of₁, The ejection function of the heart can be easily evaluated based on the change, that is, the change amount, the change rate, or the recovery curve. In addition, accurate evaluation of the blood ejection function enables diagnosis of painless myocardial ischemia.
[0047]
Further, according to the present embodiment, the first index value EV is obtained by SA10 corresponding to the evaluation unit 74.₁And the second index value EV₂Since the blood ejection function of the heart is evaluated based on the change, the blood ejection function can be accurately evaluated without skill. In addition, accurate evaluation of the blood ejection function enables diagnosis of painless myocardial ischemia.
[0048]
According to the present embodiment, SA10 corresponding to the evaluation means 74 is the first index value EV.₁And the second index value EV₂Since the blood ejection function of the heart is determined based on whether the amount of change or the rate of change between them exceeds a predetermined reference value, there is an advantage that a complicated determination algorithm is unnecessary. is there.
[0049]
Further, according to the present embodiment, SA10 corresponding to the evaluation means 74 is the second index value EV.₂First index value EV of₁Since the blood ejection function of the heart is determined based on the recovery time or recovery rate toward the heart, the evaluation of the blood ejection function is more accurate.
[0050]
Further, according to the present embodiment, the pressure pulse wave detected by the pressure pulse wave sensor 46 is converted into a pulse wave signal transmission function TF between the site where the pressure pulse wave sensor 46 is mounted and the aorta of the living body. Since the waveform conversion unit 66 further converts the waveform into the waveform in the aorta based on the first index value EV using the waveform in the aorta.₁And the second index value EV₂Is more accurately determined, so that there is an advantage that the evaluation accuracy of the blood ejection function is improved.
[0051]
Further, according to the present embodiment, the blood pressure measurement unit 60 that measures the blood pressure value of the living body using the cuff 10 and the pressure pulse wave sensor 46 detects the blood pressure value before and after the exercise load is applied to the living body. By associating the magnitude of the pressure pulse wave with the blood pressure value measured by the blood pressure measuring means 60, the pressure pulse wave P_MAnd a blood pressure value of the living body are determined in advance as shown in the figure, and a pressure pulse wave calibrating means 64 for calibrating the pressure pulse wave detected by the pressure pulse wave sensor 46 using the correspondence is provided. Further, since the pressure pulse wave is calibrated into a waveform representing the blood pressure value of the living body before and after the exercise load is applied to the living body, the first index value EV₁And the second index value EV₂There is an advantage that the relative difference that occurs before and after the exercise load is eliminated, and the evaluation accuracy of the blood ejection function is further improved.
[0052]
As mentioned above, although one Example of this invention was described based on drawing, this invention is applied also to another aspect.
[0053]
For example, in the blood pressure measurement routine in SA2 of FIG. 9 described above, the blood pressure measurement algorithm of SA2-5 to SA2-7 in FIG. 11 is executed during the slow pressure reduction period in which the pressure of the cuff 10 is reduced. The blood pressure measurement algorithm may be executed during the slow pressure increase period.
[0054]
Further, in the above-described embodiment, the waveform conversion means 66 for converting the pressure pulse wave in the radial artery 56 into the pressure pulse wave in the aorta is provided. However, the waveform conversion means 66 is not necessarily provided.
[0055]
In the above-described embodiment, both the evaluation unit 74 and the display unit 76 are provided. However, if any one of them is provided, the object of the present invention can be achieved.
[0056]
Further, the pressure pulse wave sensor 46 of the above-described embodiment is mounted on the wrist to detect the pressure pulse wave in the radial artery 56, but the pressure pulse wave in the dorsal leg artery or the pressure pulse in the carotid artery is used. It may be worn on the foot or neck to detect waves.
[0057]
In the above-described embodiment, one type selected from the first group or the second group is used as the index value EV. However, a plurality of types of index values EV are used at the same time, and the plurality of types of index values EV are used. The determination may be made comprehensively based on the determination based on the EV.
[0058]
In the blood ejection function evaluating apparatus 8 of the above-described embodiment, for example, as the index value EV, a time interval PEP from a Q wave of an electrocardiographic waveform to a rising point of a pressure pulse wave (pre-ejection period: Pre-ejection period). ) And the ejection period ET (= LVET: Left Venticular Ejection Time) from the rising point of the pressure pulse wave to the notch DN are used, and the heart is used as auxiliary information for determining myocardial ischemia. In the case of using the size of the R wave of the radio wave form or the ST level, an electrocardiographic waveform detecting device for detecting an electrocardiographic waveform is provided as necessary.
[0059]
In addition, the present invention can be variously modified without departing from the gist thereof.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a blood ejection function evaluating apparatus according to one embodiment of the present invention.
FIG. 2 is a functional block diagram illustrating a main part of a control function of the electronic control device of the embodiment of FIG. 1;
3 is a diagram illustrating a delay time DT and a blood pressure evaluation curve L calculated in a blood pressure measurement algorithm used in the embodiment of FIG.
FIG. 4 is a diagram illustrating a correspondence relationship used in the embodiment of FIG. 1;
FIG. 5 is a diagram for explaining characteristic values of a waveform of a pressure pulse wave used in the embodiment of FIG. 1;
6 is a diagram showing an example in which a second index value is displayed in comparison with the first index value on the display of the embodiment of FIG. 1;
FIG. 7 is a diagram showing an example in which a second index value is displayed in comparison with the first index value on the display device of the embodiment of FIG. 1;
8 is a diagram showing an example in which a second index value is displayed in comparison with the first index value on the display of the embodiment of FIG. 1;
FIG. 9 is a flowchart illustrating a main part of a control operation of the electronic control device of the embodiment of FIG. 1;
FIG. 10 is a time chart for explaining the control operation of FIG. 9;
FIG. 11 is a flowchart illustrating the blood pressure measurement routine of FIG. 9 in detail.
[Description of sign]
46: Pressure pulse wave sensor
60: blood pressure measuring means
61: delay time determination means
62: blood pressure evaluation curve calculation means
63: blood pressure value determining means
64: pressure pulse wave calibration means
66: Waveform conversion means
70: first index value determining means
72: second index value determining means
74: Evaluation means
76: display means

Claims (5)

A form in which a blood pressure value of the living body before and after the exercise load is measured using a cuff that compresses a part of the living body in order to evaluate the blood ejection function of the heart of the living body by applying an exercise load to the living body. Blood ejection function evaluation device,
A peripheral microphone and a trunk microphone that are provided on the peripheral side and the trunk side of the cuff and detect pulse sounds generated on the peripheral side and the trunk side of the cuff, respectively.
A delay time determining means for determining a delay time of a peripheral pulse sound detected on a peripheral side of the cuff by the peripheral microphone with respect to a fundamental pulse sound detected on a trunk side of the cuff by the trunk microphone.
By sequentially calculating the product of the loudness of the peripheral pulse sound detected by the peripheral microphone and the delay time with a change in the compression pressure of the cuff, the product changes along an axis indicating the pressure of the cuff. Blood pressure evaluation curve calculation means for obtaining a blood pressure evaluation curve,
A sharp rising point and a falling point of the blood pressure evaluation curve calculated by the blood pressure evaluation curve calculating means are detected, and cuff pressures corresponding to the rising point and the falling point are determined as a systolic blood pressure value and a diastolic blood pressure value. Blood pressure value determining means;
A pressure pulse wave sensor attached to the living body to detect a pressure pulse wave generated in synchronization with a heartbeat from the artery of the living body,
First index value determining means for determining a first index value corresponding to the systolic area of the shape of the pressure pulse wave detected by the pressure pulse wave sensor before the exercise load is applied to the living body;
Second index value determining means for determining a second index value corresponding to the systolic area of the shape of the pressure pulse wave detected by the pressure pulse wave sensor after the exercise load is applied to the living body,
An evaluation device for evaluating a blood ejection function of the heart, based on a change between the first index value and the second index value . The evaluation means determines the blood ejection function of the heart based on whether the amount of change or the rate of change between the first index value and the second index value exceeds a predetermined criterion value. The blood ejection function evaluation device according to claim 1 , which is a device. It said evaluating means, the first index value blood ejection functional evaluation of claim 1 is to determine the blood ejection function of the heart based on the recovery time or the recovery rate to recover towards the second index value apparatus. Waveform converting means for converting a pressure pulse wave detected by the pressure pulse wave sensor into a waveform in the aorta based on a transmission function between a portion where the pressure pulse wave sensor is mounted and an aorta of a living body. The blood ejection function evaluating apparatus according to any one of claims 1 to 3 , wherein: Blood pressure measuring means for measuring the blood pressure value of the living body using a cuff,
Before and after the exercise load is applied to the living body, by associating the magnitude of the pressure pulse wave detected by the pressure pulse wave sensor with the blood pressure value measured by the blood pressure measuring means, the pressure pulse wave and the correspondence between the blood pressure values of a living body in advance determined, and a pressure pulse wave calibration means for calibrating the pressure pulse wave detected by said pressure pulse wave sensor using the relationship, according to claim 1 which further contains Blood ejection function evaluation device.

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