JPH11253549A - Hemorephoretic mechanism for dialyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely and precisely mensurate a blood re-circulation amount without receiving external influences. SOLUTION: This hemorephoretic mechanism includes a light source 2 which casts a near infrared ray to a blood circuit 1 on the artery side, a light amount mensuration means (an absorbence meter) 3 to mensurate the luminous energy which has permeated the blood circuit 1, a controller 7, and a rephoretic amount calculating means (an arithmetic and logic unit) 6 which calculates a hemorephoretic amount from a period of time since the changing of a water- removing amount to the change of the luminous energy having permeated when the water-removing amount is changed in steps during a dialysis by the control device 7, and the variation amount of the permeated luminous energy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for removing blood from a dialysis patient, purifying the blood with a blood purifier, and returning the blood to the body again.
The present invention relates to a blood recirculation amount measuring mechanism of a dialysis device for measuring an amount of blood once returned to the body and returning to a blood purifier without passing through various organs in the body.

[0002]

2. Description of the Related Art In dialysis treatment, a part of blood once returned to the body returns to the blood purifier again without passing through various organs in the body. This returned blood volume is called the blood recirculation volume. This blood recirculation amount will be described below with reference to FIG. The blood from the patient's cardiopulmonary 20 goes to various organs 30 and to the dialyzer 40 (Blood Ac
cess) Divide into 10 going. Here Blood Access
A circulation (CCR) between the outlet and the inlet
This is generated when blood is taken out of the body beyond the blood flow flowing to the Blood Access 10 and serves as a measure of the blood flow that can be taken out of the body. On the other hand, the blood returned from the dialyzer 40 into the body
The thing that goes out of the body again from Blood Access 10 through is called CPR (Cardiopulmonary Recirculation),
It is essential due to the method of dialysis treatment, affects dialysis efficiency, and is an important index especially when performing short-time dialysis.

In recent years, various efforts have been made to increase the blood flow rate as much as possible to shorten the dialysis time. However, when blood is recirculated, the dialysis efficiency is reduced, and various problems are caused by insufficient dialysis without knowing the cause. May occur. Therefore, it is indispensable to grasp the amount of recirculation in order to know an appropriate dialysis time, and it is desired to develop a method for surely knowing the amount of recirculation by a simple method. Therefore, in recent years, a device that changes the temperature of the dialysate stepwise, detects the temperature change on the arterial side of the blood circuit, and measures the amount of recirculation has been put to practical use. However, the response to the temperature of the living body is very complicated and responds in a short time, and since the local temperature change of the peripheral greatly changes the temperature of the whole body,
The change in temperature of the blood returned to the body is different from the one that is simply diluted and returned. In addition, even if the temperature of the dialysate is changed, there are various portions having heat capacity, so that the temperature change of the blood returned to the body is gradual and it is difficult to improve the time accuracy of the change. It is also affected by temperature.
Therefore, it is difficult to measure the amount of blood recirculation, especially CPR. In addition, although a method of measuring the amount of blood recirculation by measuring the amount of change in drug has been proposed, it is generally said that a method of accurately grasping the amount of blood recirculation of each patient has not been established. Is the current situation.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is capable of reliably and accurately measuring the amount of blood recirculation without being externally affected. It is an object of the present invention to provide a blood recirculation amount measuring mechanism.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, the speed of movement of water in the human body and the function of maintaining homeostasis are relatively slow. In addition, when the water removal amount is changed, the change depends only on the amount of blood that has exited the body, and since the change is rapid and is not affected externally, the water removal amount is changed by changing the water removal amount. By changing the amount and detecting the change in the amount of water in the blood as a change in the amount of transmitted light, the present inventors have conceived that the amount of blood recirculation can be accurately measured, and thus completed the present invention. That is, the present invention provides a light source that irradiates near-infrared light to a blood circuit on the artery side of a patient undergoing dialysis, a light amount measuring unit that measures the amount of light transmitted through the blood circuit, a control device, and the control device. When the water removal amount is changed stepwise during dialysis, a recirculation amount calculating means for calculating a blood recirculation amount from a time from a change in the water removal amount to a change in transmitted light amount and a change amount of the transmitted light amount. Is a mechanism for measuring the amount of blood recirculation of a dialysis device comprising: Here, a laser diode is suitable as the light source. In order to remove the influence of the fluctuation of the transmitted light amount caused by the blood pulsation, an average value of the transmitted light amount during one cycle of the pulse flow is calculated, and the change amount of the average transmitted light amount is adopted as the change amount of the transmitted light amount. It is preferred that

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of a blood recirculation amount measuring mechanism according to the present invention. As shown in FIG. 1, a blood recirculation amount measuring mechanism of the present invention includes a light source 2 for irradiating near-infrared light to a blood circuit 1 on an artery side, and a blood circuit 1.
Light amount measuring means (absorbance meter) 3 for measuring the amount of light transmitted through
And the amount of transmitted light and the amount of transmitted light when the amount of water removed is changed stepwise during dialysis by the amount of transmitted water and the amount of transmitted light is changed. And a recirculation amount calculating means (arithmetic device) 6 for calculating a blood recirculation amount from the change amount of the blood flow. Hereinafter, the blood recirculation amount measuring mechanism of the present invention will be described in detail.

[0007] In many cases, dialysis is performed with a constant water removal amount, so that the absorbance on the artery side gradually increases. However, since a change may occur due to a change in a diet, a change in a body position, injection of a drug solution, or the like, an instruction to measure a blood recirculation amount is issued when a patient's condition is stabilized. When instructed, the blood circuit 1 on the arterial side is first irradiated with near-infrared light from the light source 2 and then the water removal amount control device 7 is operated to reduce the water removal amount by the water removal pump 5 to 3 to 5 L / min, for example. Hold for a minute,
Subsequently, the water removal amount is kept at, for example, 0 L / min for 3 to 5 minutes. Then, based on the time when the water removal rate was switched from 1 L / min to 0 L / min, the amount of blood recirculation was calculated by the arithmetic unit 6 from the time until the absorbance on the artery side changed and the change in the absorbance measured by the absorbance meter 3. Is calculated. In this case, the value of the water removal amount and the order of change may be changed.

[0008] It takes about 30 seconds until the blood concentration returning to the body completely changes after the setting of the water removal amount is changed.
In ACR, a change in absorbance occurs on the artery side within one minute.
On the other hand, in the case of CPR, a change in absorbance occurs on the artery side after a lapse of one minute or more after changing the setting of the water removal amount. Since the absorbance of near-infrared light substantially correlates with the hematocrit value, if the change in the absorbance is converted to the change in hematocrit value and the total blood volume of the patient is estimated from the body weight, the blood recirculation volume can be calculated as a simple pool model. Can be calculated. In this case, since the change in absorbance is completed in about 3 to 5 minutes, the effect of water moving from the somatic cells into the blood can be ignored.
The light source 2 for irradiating the blood circuit 1 is preferably a laser diode that emits light having a relatively high correlation with a hematocrit value as a single wavelength, and has a wavelength of 760 to 800 nm.
When the laser diode described above is used in combination with a collimator lens, a parallel light beam having a single wavelength can be obtained relatively easily.

When the blood concentration is measured on the arterial side by the transmission amount of near-infrared light, the transmission amount fluctuates due to the pulsation by the blood pump 4, but the change in the transmission amount caused by CPR is very small. The effect of the blood pump 4 is large. Then, in order to remove the influence of the blood pump 4, the average transmitted light amount in one or more cycles of the pulsating flow by the rollers of the blood pump 4 or the rotation cycle of the blood pump 4 is obtained from the average value of the absorbance by the absorbance meter 3. It is preferable to use the amount of change in the average amount of transmitted light as the amount of change in the amount of transmitted light. As a method of averaging the absorbance, the period of the above cycle may be converted from analog to digital at regular time intervals, and data obtained during the cycle may be added and divided by the number of data. There is also a method in which the value counted during the period of the cycle is converted from the time of the cycle to the number of counts per fixed time using a V / F converter and used.
Since the cycle of the pulsating flow by the blood pump 4 is usually about once / second, such averaging does not hinder the measurement.

The timing of measuring the amount of recirculation is desirably determined after grasping the condition of the patient, and an operation switch 8 may be provided so that the administrator can instruct measurement. In addition, the measurement result is displayed on the display 9 and the AC
For R, the flow rate of the blood pump 4 may be reduced to a flow rate at which recirculation does not occur. For CPR, the flow rate may be used as an index for dialysis management.

[0011]

As is apparent from the above description, by adopting the blood recirculation amount measuring mechanism of the present invention, the blood recirculation amount can be reliably and accurately measured without being affected by external influences. Since measurement can be performed, troubles caused by insufficient dialysis due to a decrease in dialysis efficiency can be prevented beforehand.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a blood recirculation amount measuring mechanism according to the present invention.

FIG. 2 is a diagram for explaining ACR and CPR generated during dialysis treatment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arterial blood circuit 2 Light source 3 Absorbance meter (light quantity measuring means) 4 Blood pump 5 Water removal pump 6 Recirculation amount calculating means (arithmetic device) 7 Control device 8 Operation switch 9 Display device

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toyohiro Tatsuma 3-3-1-13 Toyosaki, Kita-ku, Osaka-shi Inside Nipro Corporation (72) Inventor Hiroshi Matsumoto 3-3-1-3, Toyosaki, Kita-ku, Osaka Nipro Corporation Inside

Claims (3)

[Claims] 1. A light source for irradiating near-infrared light to a blood circuit on the artery side of a patient undergoing dialysis, a light amount measuring unit for measuring a light amount transmitted through the blood circuit, a control device, and a dialysis by the control device. When changing the amount of water removal in steps,
A blood recirculation amount measuring mechanism of a dialysis device, comprising a recirculation amount calculating means for calculating a blood recirculation amount from a time until a transmitted light amount changes after changing a water removal amount and a change amount of the transmitted light amount. 2. The blood recirculation amount measuring mechanism according to claim 1, wherein the light source is a laser diode. 3. An apparatus for calculating the average value of the transmitted light amount during one cycle of the pulsating flow in order to eliminate the influence of the fluctuation of the transmitted light amount caused by the pulsating flow of blood, and calculating the change amount of the average transmitted light amount. 4. The method according to claim 2, wherein the amount is adopted.
The blood recirculation amount measuring mechanism according to 4.