JPH0311221B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention is an electronic system using an oscillation method (oscillometric method) that extracts and calculates the pulse wave component of each heartbeat superimposed on the cuff pressure to determine the maximum and diastolic blood pressure. This relates to blood pressure monitors.

[Background Art] Conventionally, an electronic sphygmomanometer using an oscillometric method (oscillometric method) that extracts and calculates the arterial pulse wave component of each heartbeat superimposed on the cuff pressure to determine the maximum and diastolic blood pressure values is shown in Fig. 6. As shown in the figure, a pressurizing means 3 is attached to the main part 1 of the subject, and includes a pressurizing pump that pressurizes a cuff 2 that is blood-blocking the artery of the main part 1, and a pressurizing means 3 consisting of a pressure pump that gradually reduces the internal pressure of the cuff to open the artery. a pressure sensor 5 that converts the cuff internal pressure into an electrical signal during the gradual evacuation period;
Blood pressure measurement means that separates the pulse wave component contained in the output V _p of the pressure sensor 5, determines the peak and diastolic blood pressure periods based on the pulse wave components, and outputs the cuff pressure values at those times as the peak and diastolic blood pressure values. 6, display means 7 for displaying the measured systolic blood pressure value and diastolic blood pressure value, and a start switch 8 for inputting a start signal for blood pressure measurement. by the way,
When measuring blood pressure using such a vibration method, there is a problem in that if the cuff 2 is not sufficiently pressurized before the measurement starts and the artery is not completely ischemized, an incorrect blood pressure determination may be made. Ta. Therefore, conventionally, a re-inflation determining means has been provided which detects insufficient pressurization of the cuff 2 and instructs re-inflation. That is, the output V _p of the pressure sensor 5 is as shown in FIG. 7, and the re-pressurization determination means provided in the blood pressure measuring means 6 indicates that the pressurization of the cuff 2 by the pressurizing means 3 has been stopped. It is determined whether a pulse wave B' equal to or higher than a predetermined determination level has occurred during a predetermined determination time T set by a determination time setting timer from time point A, and a pulse wave B' equal to or higher than a determination level is determined. If this had occurred, it would be determined that the pressure was insufficient and an instruction would be given to re-pressurize the cuff 2. In addition, depending on the re-pressurization instruction, the pressurizing means 3 such as a pressurizing pump is automatically operated to perform automatic re-pressurizing, or the person being measured is given a manual pressurizing means (for example, a rubber ball). Whether manual repressurization is performed by operating 3 is selected depending on the pressurization method. In addition, pulse waves exceeding a predetermined judgment level
Needless to say, if B' is not detected and it is determined that repressurization is not necessary, the blood pressure is measured using the pulse wave B obtained thereafter. Here, the predetermined level, which is the criterion for the repressurization determination means, is set to an appropriate value in consideration of numerical errors and noise in the calculation, and is set to an appropriate value that is an effective pulse wave that indicates a state in which the blood flow in the artery is not stopped. are set to ensure reliable detection. By the way, in actual blood pressure measurement, even though the arteries in the main part 1 are completely ischemized by the cuff 2, pulsations due to blood flow are transmitted to the cuff 2 from areas other than the ischemic part (mainly from the heart side). When the judgment level, which is the judgment standard of the repressurization judgment means, is set low, the pressure sensor 5 due to this pulsation
There was a problem in that the pulsation of the output V _p was detected as a pulse wave B', and re-pressurization was performed even though re-pressurization was not necessary, causing blood stasis in the ischemic area. The above phenomenon is likely to occur when the subject's pulse is strong. Therefore, in order to solve the above problem, if the judgment level that is the judgment standard of the repressurization judgment means is set high, the above problem will be solved, but if the pulse of the subject is weak, Even though pressurization was necessary, it was determined that re-pressurization was not necessary, and blood pressure measurement was started with insufficient pressurization and the main artery in artery 1 was not ischemized, resulting in incorrect blood pressure determination. There was a problem with what was being done.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and its purpose is to determine whether or not it is necessary to re-inflate the cuff based on the state of the pulse wave of the subject. The purpose of the present invention is to provide an electronic blood pressure monitor that can be used appropriately.

[Disclosure of the Invention] FIG. 1 shows the configuration of an embodiment of the present invention.
Judgment by the repressurization determining means 12 when repressurization is performed by the pressurizing means 3 based on a repressurization instruction in an electronic blood pressure monitor using the vibration method provided with the repressurization determining means 12 similar to the conventional example Judgment standard changing means 1 for changing the standard based on the pulse wave signal from the previous judgment
5, and the blood pressure measuring means 6 includes:
Separation and extraction means 10 consisting of a cuff pressure extraction means 9a for extracting a cuff pressure component from the output V _p of the pressure sensor 5 and a pulse wave extraction means 9b for extracting a pulse wave component.
Then, the systolic blood pressure period and the diastolic blood pressure period are determined based on the pulse wave signal V output from the separation means 10, and the systolic and diastolic blood pressure values determined based on the cuff pressure signal P extracted at that period are determined. It is formed by a control circuit section 11 that displays on the display means 7 and controls the repressurization determination means 12 and the determination criterion changing means 15. In this embodiment, the judgment criterion changing means 15 includes a timer 13 for setting a predetermined judgment time T, and a reference voltage for changing the judgment level L by the judgment level up signal Vl from the control circuit section 11. It is formed with a generating circuit 14,
The determination level L generated by the reference voltage generating means 14 is changed based on the level of the pulse wave component V at the previous determination, and is increased by a certain amount when it was determined that the pressurization was insufficient last time. .

By the way, the first judgment level L is determined based on the information obtained by the doctor's auscultation and clinical measurement so that the degree of matching is high, and is set in advance in the program ROM as a value unique to the electronic blood pressure monitor. be. In addition, the fixed amount to be pumped up is similarly determined based on clinical measurement information.
Set as a unique value. Note that these values are
The transmission rate of vibration to the pressure sensor changes depending on the cuff band, pressurization speed, etc., so it is determined at the time of programming during product development.

Below, the operation of the embodiment will be explained in Figures 2 and 3.
This will be explained using figures. Figure 2a is a flowchart showing the overall operation, Figure 2b is a flowchart showing the internal operation of the repressurization determining means, Figure 3 is an explanatory diagram of the operation, and Figure 3a is the output of the pressure sensor 5. _Vp ,
The figure b shows the pulse wave signal V extracted by the pulse wave extraction means 9b from the output V _p of the pressure sensor 5, the figure c shows the judgment result signal V ₀ by the re-pressurization judgment means 12, and the figure d shows the control circuit section 11. The result of detection of insufficient pressurization in the same figure e
is the pulse wave signal V' for blood pressure measurement. In addition, the third
In the figure, in order to show the characteristics of the pulse wave signal, the amplitude of the pulse wave signal (vibration component) is illustrated as being large, but the actual amplitude is about several mmHg, and the amplitude as shown in the figure is isn't it. Now, when the pressurization of the cuff 2 is stopped, the time setting timer 13 is started, and it is checked whether a valid pulse wave is input within a predetermined judgment time T set by the time setting timer 13. The repressurization determination means 12 checks based on the determination level L. This check operation is as shown in Fig. 2b, in which the voltage level output from the pulse wave extraction means is compared with the voltage level output from the reference voltage generation circuit, and a timer is set. As a result, if re-pressurization is not required, it outputs "L" level, and in other cases, it outputs the voltage level signal as is to the control circuit section. It's summery. Here, if an effective pulse wave larger than the determination level L is not detected by the time the time setting timer 13 times up, the re-compression determining means 12 outputs a determination result signal V ₀ indicating that re-compression is not necessary. Ru. The control circuit unit 11 to which this determination result signal V ₀ is input assumes that the arterial ischemia has been completed, executes a blood pressure determination routine, and performs a predetermined blood pressure measurement operation. On the other hand, when a valid pulse wave is detected and the re-inflation determining means 12 outputs the determination result signal V ₀ for instructing re-inflation, the control circuit section 11 sends the determination criterion changing means 1
5, a judgment level up signal Vl is output, and the judgment level L of the judgment standard is raised by a certain amount. Next, an insufficient pressurization display is displayed to inform the subject of the insufficient pressurization and prompt the patient to re-inflate the cuff 2, and in the case of an automatic pressurization type, a pressurization pump drive signal is displayed. is output to automatically repressurize. Next, it is checked whether the cuff pressure has increased by +30 mmHg from the previous time, and if it has increased, the insufficient pressurization display is erased and the above-mentioned re-pressurization judgment operation is repeated. In the case of FIG. 3, the judgment bell of the re-pressurization judging means 12 is set to L ₁ , and the first judgment is that the pressurization is insufficient (the judgment result signal V ₀ is "L").
As a result, the judgment level was raised to L ₂ and a second judgment was made, and as a result, it was again judged that there was insufficient pressurization, so the judgment level was further increased and a third judgment was made. This shows an example in which an effective pulse wave cannot be obtained within the judgment time T and the insufficient pressurization is resolved (judgment result signal V ₀ is at "L" level). Systolic blood pressure and diastolic blood pressure are determined based on the wave signal V'.

Therefore, in this embodiment, when repressurization is performed by the pressurizing means 3 based on a repressurization instruction, the determination level L of the determination standard of the repressurization determining means 12 is set to the pulse rate at the previous determination. Since the judgment criterion changing means 15 is provided to change based on the wave signal V, it is possible to reliably judge whether re-pressurization is necessary regardless of the strength of the pulse of the subject, and to avoid unnecessary re-pressurization. This prevents blood pressure from being caused in the ischemic area due to blood pressure, and prevents erroneous blood pressure determinations due to blood pressure measurement being started in a state where blood pressure is insufficient.

The pulse wave signal V input to the recompression determining means 12 is a pulse wave height value or an area value, and depends on the extraction method by the pulse wave extracting means 9b, and the determination level L is based on the pulse wave of each method. Needless to say, it is set to an appropriate value corresponding to the wave signal V. By reusing the pulse wave extraction means 9b used for blood pressure measurement in this way, the configuration can be simplified and costs can be reduced. Further, in this embodiment, the determination level L is increased any number of times each time it is determined that re-pressurization is necessary, but the determination level L may not be changed upon re-determination from the second time onwards. That is,
The purpose of raising the judgment level L is to eliminate the influence of pulsation after ischemia that occurs when the pulse of the garment being measured is strong, and it is clear that there is no need to raise the judgment level indefinitely. If the judgment level L is increased and the judgment is made again, and the insufficient pressurization is not resolved, the judgment is made again by increasing the judgment level L by the same amount as before. This is because the determination can be made accurately.

Embodiment 2 FIG. 4 shows another embodiment, in which an electronic blood pressure monitor similar to that of Embodiment 1 has a determination criterion changing means 1.
5' is formed by a timer 13 for setting a predetermined time T and a timer 16 for measuring the pulse wave cycle, and the determination time T, which is the criterion for the re-compression determining means 12, is determined by the pulse wave signal at the previous determination. This is changed based on the period T _v of the pulse wave signal V, and in this embodiment, the judgment time T' at the time of re-judgment is set to twice the period T _v of the pulse wave signal V. . Note that the normal (first) judgment time T is set to about 2 beats in the case of 40 beats/minute, which is the lowest pulse rate for a normal healthy person, so it is set at the time of re-judgment. The determination time T' will be shorter than the initially set determination time T.

The operation of the embodiment will be explained below using the flowchart shown in FIG. At the time of the first re-pressurization determination, if an effective pulse wave is obtained within the set time T and it is determined that the pressurization is insufficient, the cycle measurement timer 16 is activated when the first pulse wave is obtained. At the same time, when the next pulse wave is obtained, the cycle measuring timer 16 is stopped and the cycle Tv of the pulse wave signal _V is measured. The control circuit section 11 to which this measurement result Vt is input forms a time setting signal V _T for changing the time setting of the time setting timer 13 based on this measurement result, and sets the judgment time T' at the time of re-judgment.
I'm starting to set it to 2T _v . In this way, the judgment time T' at the time of re-judgment is set by the pulse wave signal V at the time of the previous judgment.
This makes it possible to quickly determine if there is insufficient pressurization after re-pressurization, without taking an unnecessarily long time to re-evaluate, and to quickly move on to blood pressure measurement. .

[Effects of the Invention] As described above, the present invention includes a pressurizing means for pressurizing a cuff to isovascularize an artery in a main part of a subject, a gradual evacuation means for gradually reducing the internal pressure of the cuff to open the artery, A pressure sensor converts the cuff internal pressure during the gradual evacuation period into an electrical signal, and a pulse wave component included in the output of the pressure sensor is separated, and based on the pulse wave component, the highest and lowest blood pressure periods are determined, and the cuff at that period is adjusted. blood pressure measurement means for outputting pressure values as maximum and diastolic blood pressure values, and whether a pulse wave signal equal to or higher than a predetermined determination level is generated within a predetermined determination time after the pressurization means finishes pressurizing the cuff. In an electronic sphygmomanometer equipped with a re-pressurization determination means that determines insufficient pressurization and issues a re-pressurization instruction when a pulse wave signal equal to or higher than the determination level is detected, The device is equipped with a judgment criterion changing means that changes the judgment criterion of the repressurization judging means when repressurization is performed by the pressurizing means based on the pulse wave signal from the previous judgment. It is possible to reliably determine whether re-pressurization is necessary regardless of the strength of blood pressure, and blood pressure measurement can be performed when unnecessary re-pressurization causes congestion in the ischemic area or when blood ischemia is insufficient. It is possible to prevent erroneous blood pressure determinations due to the start of blood pressure determination, and to shorten the time required for re-diagnosis.
This has the advantage that it is possible to appropriately or quickly determine whether re-pressurization is necessary depending on the state of the pulse wave of the subject.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a schematic configuration of one embodiment of the present invention, Fig. 2 is a flowchart showing the same operation, Fig. 3 is an explanatory diagram of the same operation, and Fig. 4 shows the structure of another embodiment. 5 is a flowchart showing the operation of the same as above, FIG. 6 is a block diagram showing a schematic configuration of a conventional example, and FIG. 7 is an explanatory diagram of the same operation. 1 is the main part, 2 is the cuff, 3 is the pressurizing means, 4 is the gradual evacuation means, 5 is the pressure sensor, 6 is the blood pressure measuring means, 12 is the re-pressurization judgment means, and 15, 15' are the judgment criterion changing means. be.

Claims (1)

[Scope of Claims] 1. A pressurizing means for pressurizing a cuff to isovascularize an artery in a main part of a subject; a gradual evacuation means for gradually reducing internal pressure of the cuff to open the artery; A pressure sensor that converts internal pressure into an electrical signal and a pulse wave component included in the output of the pressure sensor are separated, and based on the pulse wave component, the highest and lowest blood pressure periods are determined, and the cuff pressure values at that time are the highest and lowest. A blood pressure measurement means for outputting a blood pressure value,
It is detected whether or not a pulse wave signal of a predetermined judgment level or higher is generated within a predetermined judgment time after the end of cuff pressurization by the pressurizing means, and the pressure is applied when a pulse wave signal of a judgment level or above is detected. In an electronic sphygmomanometer equipped with a re-pressurization determining means that determines that there is insufficient pressure and issues a re-pressurization instruction, the re-pressurization determination means determines when re-pressurization is performed by the pressurizing means based on the re-pressurization instruction. The standard is the level of the pulse wave signal, and a judgment standard changing means is provided for changing the above judgment standard (judgment level) based on the level of the pulse wave signal at the previous judgment, and the judgment level is set when insufficient pressurization was determined last time. An electronic blood pressure monitor characterized by increasing the blood pressure by a certain amount. 2. A pressurizing means for pressurizing the cuff to ischemize arteries in important parts of the subject, a gradual evacuation means for gradually reducing the cuff internal pressure to open the arteries, and converting the cuff internal pressure into an electrical signal during the gradual evacuation period. A pressure sensor that separates the pulse wave component included in the output of the pressure sensor, determines the peak and diastolic blood pressure periods based on the pulse wave components, and outputs the cuff pressure values at those times as the peak and diastolic blood pressure values. and a measuring means,
It is detected whether or not a pulse wave signal of a predetermined judgment level or higher is generated within a predetermined judgment time after the end of cuff pressurization by the pressurizing means, and the pressure is applied when a pulse wave signal of a judgment level or above is detected. In an electronic sphygmomanometer equipped with a re-pressurization determining means that determines that there is insufficient pressure and issues a re-pressurization instruction, the re-pressurization determination means determines when re-pressurization is performed by the pressurizing means based on the re-pressurization instruction. An electronic sphygmomanometer, characterized in that the reference is the period of the pulse wave signal, and further comprises a judgment criterion changing means for changing the judgment criterion (judgment time) based on the period of the pulse wave signal at the time of the previous judgment.