JPH11317A - Automatic blood pressure measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic blood pressure measuring device capable of quickly measuring the blood pressure value of a patient dialyzed, in relation to an increase in hematocrit value Ht. SOLUTION: If any of hematocrit values Ht detected continuously by a hematocrit detecting device 72 exceeds a preset reference value A, the blood pressure measuring action of a blood pressure determination means 80 is started automatically by a blood pressure measurement actuation means 84 and therefore the blood pressure value of a patient dialyzed can be measured promptly in relation to a decrease in the amount of circulating blood plasma of the dialyzed patient, whereby a treatment can be made quickly for a decrease in blood pressure of the patient dialyzed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic blood pressure measuring device for measuring the blood pressure of a living body during hemodialysis.

[0002]

2. Description of the Related Art Hemodialysis, which is known as one of the remedies for renal insufficiency, involves a patient's blood and an electrolyte solution across a dialysis membrane in an extracorporeal circulation device (dialysis device, artificial kidney) for a long time of about several hours. This is performed by performing substance exchange and separation between the blood and the dialysate while the dialysate is circulated. As a problem that occurs in conjunction with such hemodialysis treatment, there is a problem called dialysis hypotension in which the blood pressure value of a dialysis patient sharply decreases. Such dialysis hypotension causes various problems in continuing dialysis therapy, and therefore requires prompt treatment.

In dialysis therapy, a large amount of extracellular fluid mainly containing intravascular fluid is removed within a relatively short period of time. Intravascular return velocity (plasma refilling r
ate), the circulating plasma volume decreases, and this decrease is considered to be the main cause of dialysis hypotension in dialysis patients. For this reason,
Using the fact that the circulating plasma volume can be expressed by a hematocrit value Ht indicating a blood cell volume (%) in the blood of a dialysis patient, the hematocrit value is measured using a non-invasive continuous hematcrit detector. By continuously monitoring Ht, it is possible to predict a decrease in blood pressure of a dialysis patient.

[0004]

However, in the above case,
Each time the hematocrit value Ht rises, it is necessary to measure and confirm the blood pressure value of the dialysis patient using a blood pressure measurement device provided with a cuff. In practice, however, a single medical worker operates a plurality of extracorporeal circulation devices. In many cases, the blood pressure of the dialysis patient is difficult to measure immediately after the increase of the hematocrit value Ht because of the management or operation, and there is a possibility that the treatment for the decrease in the blood pressure of the dialysis patient is delayed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to quickly measure the blood pressure of a dialysis patient in association with an increase in the hematocrit value Ht. An automatic blood pressure measurement device is provided.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the gist of the present invention is to measure a blood pressure value of a living body by changing a pressure applied to a part of the living body using a cuff. An automatic blood pressure measurement device provided with a blood pressure measurement means, wherein (a) a hematocrit detection device that continuously detects the hematocrit value of the living body, and (b) a hematocrit value that is continuously detected by the hematocrit detection device. A blood pressure measurement activation means for automatically starting a blood pressure measurement operation of the blood pressure measurement means based on exceeding a predetermined reference value.

[0007]

In this manner, when the hematocrit value continuously detected by the hematocrit detection device exceeds a predetermined judgment reference value, the blood pressure measurement activation means causes the blood pressure measurement Start the measurement operation automatically. Therefore, according to the present invention, the blood pressure value of the dialysis patient can be promptly measured in relation to the decrease in the circulating plasma volume of the living body, so that the treatment for the decrease in the blood pressure of the living body can be performed promptly. Become.

[0008]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram illustrating a circuit configuration of an automatic blood pressure measurement device 8 for hemodialysis to which the present invention is applied.

In FIG. 1, an automatic blood pressure measurement device 8 has a cuff 10 which has a rubber bag in a cloth band-shaped bag and is wound around a part of a living body such as an upper arm or a thigh of a dialysis patient.
And a pressure sensor 14, an exhaust control valve 16, and an air pump 18 connected to the cuff 10 via a pipe 20. The exhaust control valve 16 includes, for example, a pressure supply state that allows supply of pressure into the cuff 10, a slow discharge state that gradually releases the pressure in the cuff 10, and a rapid discharge pressure that rapidly releases the pressure in the cuff 10. It is configured to be able to switch between three states.

The pressure sensor 14 detects the pressure in the cuff 10 and outputs a pressure signal SP representing the pressure to the static pressure discriminating circuit 2.
2 and the pulse wave discrimination circuit 24. The static pressure discriminating circuit 22 has a low-pass filter, discriminates a cuff pressure signal SK representing a steady pressure included in the pressure signal SP, that is, a cuff pressure, and converts the cuff pressure signal SK into an A / D converter 26.
To the electronic control unit 28 via the Pulse wave discrimination circuit 2
Reference numeral 4 denotes a band pass filter, which discriminates the frequency of the pulse wave signal SM ₁ which is a vibration component of the pressure signal SP, and converts the pulse wave signal SM ₁ via the A / D converter 26 into the electronic control unit 2.
8 The cuff pulse wave represented by the pulse wave signal SM ₁ is
This is a pressure vibration wave generated in the cuff 10 generated from a brachial artery (not shown) in synchronization with the heartbeat of the patient.

The electronic control unit 28 includes a CPU 30, R
OM32, RAM34, output port 36, input port 3
The CPU 30 outputs a drive signal from the output port 36 by executing signal processing using the storage function of the RAM 34 in accordance with a program stored in the ROM 32 in advance. By controlling the exhaust control valve 16 and the air pump 18, the measured blood pressure value is displayed on the display 40.

The extracorporeal circulation device 50 for hemodialysis is also called a dialysis device or an artificial kidney, and includes a dialysate circulation circuit 56 for circulating a dialysate between a dialysate supply device 52 and a dialyzer 54. Dialysis patient 58, blood pump 60, drip chamber 62, dialyzer 5
4. An extracorporeal blood circulation circuit 68 for circulating blood between drip chambers 66 having a venous pressure gauge 64, and a heparin infusion device 70. The dialyzer 54
Is provided with a dialysis membrane having a membrane area of about 1 to 2 m ² composed of, for example, about 10,000 hollow fibers so that blood and dialysate can pass through the inside and outside of the hollow fibers, respectively. Has become.

In order to prevent the compression by the cuff 10 from obstructing the blood circulation, the part of the dialysis patient 58 to which the extracorporeal blood circulation circuit 68 is connected is selected from the limbs where the cuff 10 is not wound. You. For example, when the cuff 10 is wound around the right arm, the vein in the left arm is connected to the extracorporeal blood circulation circuit 68.

Optical non-invasive hematocrit detector 72
Includes a sensor clip 74 mounted so as to sandwich the transparent container of the drip chamber 62 and incorporating a light emitting element for projecting light of a predetermined wavelength to blood and a light receiving element for receiving transmitted light and scattered light in blood. The hematocrit value Ht is sequentially calculated based on the light received by the light receiving element, and is continuously output to the input port 38 of the electronic control unit 28. Since the hematocrit value Ht in blood indicates the blood cell volume (%) in blood, the increase is
Volume (100-Ht)% excluding the blood cell volume in the blood
Means a decrease in plasma volume.

The input port 38 of the electronic control unit 28
A start / stop push button 76 for starting or stopping the blood pressure measurement operation, a manual start mode for enabling the operation of the start / stop push button 74, the operation of the start / stop push button 74 being disabled, and the hematocrit value H
A mode changeover switch 78 for selecting one of an automatic activation mode for automatically activating a blood pressure measurement when t exceeds a predetermined reference value is connected.

FIG. 2 is a functional block diagram for explaining a main control function of the electronic control unit 28. As shown in FIG. 2, blood pressure measuring means 80, the target pressure value pressing pressure is in a predetermined cuff 10 wound around the upper arm, for example vivo by the cuff-pressure changing means 82 P _CM (e.g., pressure values of about 180 mmHg) until quick increasing Then, during the slow down period in which the blood pressure is gradually reduced at a speed of about 3 mmHg / sec, a well-known oscillometric method is used based on the change in the amplitude of the pulse wave represented by the pulse wave signal SM ₁ which is sequentially collected. And systolic blood pressure B
P _SYS , mean blood pressure value P _MEAN , and diastolic blood pressure value BP _DIA
Decide etc.

The automatic start mode judging means 83 judges whether or not the automatic start mode is selected by the mode changeover switch 78. The blood pressure measurement activating means 84 is provided in the extracorporeal blood circulation circuit 68 continuously detected by the hematocrit detecting device 72 when the automatic activating mode determining means 83 determines that the automatic activating mode is selected. On the basis of the fact that the hematocrit value Ht of the blood exceeds a predetermined criterion value A%, that is, the fact that the blood plasma volume of the blood falls below a predetermined criterion value (100-A)%, The blood pressure measurement operation of the determining means 80 is started automatically. Above criterion value A%
Is that the rate of water removal of the extracorporeal circulation device 50 from the blood of the dialysis patient 58 is changed from the extravascular to the intravascular flow rate (plasma
It is determined experimentally in advance to determine that the circulating plasma volume has decreased to such an extent that hypotension occurs beyond the refilling rate.

FIG. 3 is a flowchart for explaining a main part of the control operation in the electronic control unit 28 of the blood pressure monitoring device 8. In FIG. 3, in step SA1 (hereinafter, the steps are omitted) corresponding to the automatic start mode determining means 83, it is determined whether or not the automatic start mode is selected by the mode switch 78. This SA1
Is negative, it is determined in SA2 whether a manual start operation has been performed by operating the start / stop push button 76. If the determination at SA2 is denied, the present routine is terminated. If the determination is affirmed, the blood pressure measurement routine at SA5 and lower is executed.

That is, it corresponds to the cuff pressure control means 82.
In SA5, SA6, and SA7, the exhaust control valve 1
6 is switched to the pressure supply state and the air pump 18
By being driven, the cuff 10 can be quickly
When the rapid pressure increase is started and the cuff pressure P_CIs 180mmHg
Target compression pressure P set in advance_cmWhether or not
Is determined. When the judgment of SA6 is denied
Is repeated by repeatedly executing the above SA5 and below.
Pressure P_CContinues to rise. However, the cuff pressure P _Cupon
If the determination in SA6 is affirmative, the air pump
18 is stopped and the exhaust control valve 16 is slowly exhausted.
Is switched to the air state and the cuff pressure P_CIs about 3-5mmHg / sec
It can be lowered at a moderate speed.

Next, at SA8, it is determined whether or not a pulse wave has occurred in the cuff 10 based on an output signal from the pulse wave discrimination circuit 24. If the determination in SA8 is denied, the above-described SA7 and subsequent steps are repeatedly executed. If the determination in SA8 is affirmed, the blood pressure measurement means 80
In SA9 corresponding to the above, the blood pressure measurement algorithm is executed. That is, based on the change in the amplitude of the pulse wave represented by the pulse wave signal SM ₁ sequentially obtained in the slow pressure step-down process in which the pressure in the cuff 10 is decreased at a gentle speed, the well-known oscillometric blood pressure value is used. The systolic blood pressure value BP _SYS , the average blood pressure value BP _MEAN , and the diastolic blood pressure value BP _DIA are determined according to the determination algorithm.

At SA10, whether or not the blood pressure measurement at SA9 has been completed, that is, the systolic blood pressure value BP _SYS and the average blood pressure value BP according to the above-described blood pressure value determining algorithm.
_It is determined whether the determination of _MEAN and the diastolic blood pressure value BP _DIA have all been completed. Next, in SA11, the exhaust control valve 16 is switched to the rapid exhaust pressure state to rapidly exhaust the pressure in the cuff 10, and in SA12, the measured blood pressure value and the pulse rate determined from the pulse wave interval in steps (not shown). Are displayed on the display 40.

However, if the automatic movement mode is selected, the judgment at SA1 is affirmative, so that the hematocrit value Ht of the blood of the dialysis patient is read based on the signal from the hematocrit detecting device 72 at SA3. It is. Next, S corresponding to the blood pressure measurement activation unit 84
In A4, it is determined whether or not the actual hematocrit value Ht is higher than a predetermined reference value A%, that is, whether the plasma volume of the dialysis patient is lower than a predetermined reference value (100-A)%. Is determined.

If the determination at SA4 is denied, this routine is terminated. If the determination is affirmed, SA5 and subsequent steps are executed in the same manner as at the time of the manual start-up operation. Measurement operation is hematocrit value H
Triggered automatically in connection with a rise in t.

As described above, according to the present embodiment, when the hematocrit value Ht continuously detected by the hematocrit detecting device 72 exceeds the predetermined criterion value A, the blood pressure measurement activating means 84 (SA4). Since the blood pressure measurement operation of the blood pressure measurement means 80 (SA9) is automatically started, the blood pressure value of the dialysis patient can be promptly measured in relation to the decrease in the circulating plasma volume of the dialysis patient. It becomes possible to quickly perform treatment for a decrease in the blood pressure of the patient.

While the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be applied to other embodiments.

For example, the blood pressure measuring means 8 of the aforementioned embodiment
0 is configured to measure the blood pressure by the so-called oscillometric method, but measures the blood pressure by the so-called K sound method that determines the cuff pressure at the time of occurrence and disappearance of the Korotkoff sound as the systolic blood pressure value and the diastolic blood pressure value. It can be anything.

Although the criterion value A% used in SA4 of the above-described embodiment may be a fixed value, a preset value set for each individual dialysis patient may be used. The reference value A% in SA4 is
It may be set as a change width based on the previous hematocrit value Ht.

The sensor clip 74 of the hematocrit detector 72 of the above-described embodiment is
Although provided in the drip chamber 62 located on the more upstream side, it may be provided in a part of the extracorporeal blood circulation circuit 68 such as a drip chamber 66 located on the downstream side of the dialyzer 54.

Further, the automatic blood pressure measurement device 8 of the above-described embodiment is used.
Has been used for hemodialysis patients, but is also applicable to patients undergoing blood exchange or transfusion, for example.

The present invention can be modified in various other ways without departing from the gist thereof.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a circuit configuration of an automatic blood pressure measurement device for hemodialysis according to an embodiment of the present invention.

FIG. 2 is a functional block diagram illustrating a main part of a control function of an electronic control device in the embodiment of FIG. 1;

FIG. 3 is a flowchart illustrating a main part of a control operation of an electronic control unit in the embodiment of FIG. 1, and is a diagram illustrating a blood pressure monitoring routine.

[Explanation of symbols]

 8: Automatic blood pressure measurement device for hemodialysis 10: Cuff 72: Hematocrit detection device 80: Blood pressure measurement means 84: Blood pressure measurement activation means

Claims (1)

[Claims] 1. An automatic blood pressure measurement device comprising a blood pressure measurement means for measuring a blood pressure value of a living body by changing a compression pressure on a part of the living body using a cuff, wherein the hematocrit value of the living body is measured. A hematocrit detecting device that continuously detects the blood pressure, and automatically performs a blood pressure measuring operation of the blood pressure measuring means based on a hematocrit value continuously detected by the hematocrit detecting device exceeding a predetermined reference value. An automatic blood pressure measurement device, comprising: