JP2009136704A - Dialyzing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dialyzing system which performs reliable and safe dialysis by reducing the possibility of causing unfavorable symptoms (shock disease) such as a decline in blood pressure, headache, vomiting and muscle spasm which may occur to a patient during dialysis. <P>SOLUTION: This dialyzing system, comprising a dialyzer, an extracorporeal circulation circuit, a dialysis instrument and a dialysis fluid circuit, is provided with a blood water level measuring means 11, 12 for monitoring the amount of water level and/or changes in water level in the blood flowing the extracorporeal circulation circuit during dialysis. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a medical device, and more particularly to a dialysis device. More specifically, the present invention relates to a dialysis apparatus that can perform appropriate dialysis by monitoring the blood state of a patient during dialysis.

Dialysis is being performed for patients whose renal function is impaired and therefore cannot adjust their water content and cannot drain urine. Dialysis is a treatment method that purifies blood by bringing dialysate and blood into contact with each other via a dialyzer. Its purpose is to purify the blood and discharge (remove) excess water to reduce the amount of water in the body. It is possible to adjust. The present invention relates to adjustment of the amount of water in the body, that is, control of water removal by ultrafiltration performed by a dialyzer through a dialyzer.
This dehydration is performed mainly by providing a differential pressure (TMP) between blood and dialysate via a dialyzer, and the purpose of the dehydration is fairly accurately within a predetermined time due to recent advances in dialysis machine technology. It is possible to remove a predetermined amount of water. In addition, the target water removal amount (total water removal amount) is divided evenly per unit time to remove water, or at the initial stage of dialysis, for example, a lot of water is removed per unit time, and the latter half is reduced. A method (UF program) for performing water removal by combining a program is performed. However, the total water removal amount was determined by doctors based on various indicators.
In determining the water removal amount for each dialysis, an index called a reference weight (dry weight) is important. This is the weight when all excess water in the dialysis patient's body has been removed. For example, the patient's weight is measured before dialysis, and the difference between the measured value and the dry weight is the total amount of water removed. Is set in a dialysis machine to remove water.

However, this dry weight is different from each standard weight and ideal weight, and is different for each patient, so that it was extremely difficult to determine. In addition, even if an appropriate dry weight has been determined, in order to bring it closer to the dry weight, sudden water removal temporarily reduces the patient's blood circulation volume, resulting in decreased blood pressure, headache, Unpleasant symptoms (shock symptom) such as vomiting and muscular silicosis may occur, which may cause dialysis to be stopped halfway.
Furthermore, if the dry weight is not appropriate, for example, if the dry weight setting is lower than the appropriate value, the same symptoms as described above may occur, and if the dry weight is higher than the appropriate value, excessive excess in the patient's body. Water is accumulated, and it may be considered that the patient has serious effects such as an increase in blood pressure, a decrease in pulmonary function, and cardiac hypertrophy.
In addition, for example, even if the dry weight setting for a certain patient during dialysis is appropriate, the patient's biological conditions are constantly changing, and treatment is not always safely performed under the same conditions during the next dialysis. It was.

  Therefore, a method for predicting the occurrence before the occurrence of the unfavorable symptoms as described above and suppressing the occurrence is disclosed (for example, Patent Document 1), which measures the hematocrit value of blood circulating extracorporeally, The blood circulation volume is estimated from the value, and the change is monitored.

Japanese Patent No. 2869735

  However, in the conventional technique, since a change in blood circulation volume is indirectly estimated by measuring a hematocrit value of blood, there is a high possibility that an error will occur. Furthermore, hematocrit is generally less than half of the blood component, especially in dialysis patients, which is generally lower than in healthy individuals. Therefore, accurate measurement was difficult. In addition, in order to obtain a hematocrit value by an ultrasonic sensor that requires correction of the measurement value depending on the temperature of the measurement object, a temperature sensor is provided on the extracorporeal circuit to correct the measurement value. However, it has been considered that the temperature of the extracorporeal circuit is also affected by the atmosphere in which it is placed, that is, the temperature sensor for correcting the ultrasonic sensor is also affected, and an accurate value cannot be obtained. In addition, a dedicated extracorporeal circuit is required to obtain the most accurate temperature measurement value using the temperature sensor, leading to increased costs.

Further, in the measurement of the hematocrit value, it is considered necessary to take into account the recirculation of blood that has been circulated extracorporeally. This blood recirculation means that the blood derived from the patient passes through the dialyzer by the extracorporeal circuit, and then the blood that returns from the vein side of the extracorporeal circuit to the body returns to the artery side again without returning to the heart. Means flowing into the extracorporeal circuit. When recirculation occurs, blood whose water content has decreased, that is, concentrated blood flows again into the extracorporeal circuit, so that blood concentration before dialysis occurs, and the apparent hematocrit value increases. That is, if recirculation is occurring, the blood flowing through the extracorporeal circuit cannot be said to represent a true patient condition, that is, the hematocrit obtained by measuring the blood with that recirculation. It is conceivable that the measured value has no meaning.
Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide a dialysis apparatus that solves the above problems.

That is, the present invention
(1) Blood water content measuring means capable of monitoring the value and / or change in blood water content of blood flowing through the dialyzer, extracorporeal circuit, dialysis device, dialysate circuit, and extracorporeal circuit during dialysis A dialysis machine characterized by comprising:
(2) The dialysis apparatus further includes means for detecting recirculation of blood circulating outside the body, and the dialysis apparatus according to (1) above,
(3) The dialysis apparatus according to (1) or (2) above, further comprising calibration means for calibrating blood water content measurement means;
(4) The dialysis apparatus according to (3) above, wherein the calibration means of the blood water content measurement means is by changing the water removal rate by a dialysis machine,
(5) The dialysis apparatus according to (3) above, wherein the calibration means of the blood water content measuring means is a water content increasing means for increasing the water content of blood flowing in the extracorporeal circuit by a known amount;
(6) The dialysis apparatus according to (5) above, wherein the water amount increasing means is means for injecting an infusion solution into the extracorporeal circuit.
(7) The dialysis apparatus according to (6), wherein the moisture amount increasing means includes a temperature adjusting means for adjusting the infusion solution to a predetermined temperature;
(8) The water amount increasing means is a means by reverse filtration to an extracorporeal circuit using a dialysis machine and a dialyzer, and the dialysis apparatus according to (5) above,
(9) The calibration means of the blood water content measuring means intentionally changes the temperature of the dialysate flowing through the dialysate circuit by a dialysis device, thereby changing the temperature of the blood flowing through the extracorporeal circuit to an approximately equivalent change. The dialysis apparatus according to (3) above, which is caused by
(10) The dialyzer further has a temperature sensor for measuring the temperature of the dialysate flowing through the dialysate circuit, and corrects the value obtained from the blood moisture measuring means by the measured value obtained from the temperature sensor. The dialysis device according to any one of the above (1) to (9), which has a correcting means,
(11) The blood water content measuring means includes an ultrasonic sensor, and the ultrasonic sensor is installed in the arterial extracorporeal circuit and the venous extracorporeal circuit with respect to the heart of the extracorporeal circuit. (10) the dialysis device according to any one of
(12) The ultrasonic sensor provided in the arterial extracorporeal circuit relates to the dialysis apparatus according to (11), which measures a blood flow rate flowing in the extracorporeal circuit.

According to the said structure, it becomes possible to grasp | ascertain the condition of the blood under dialysis treatment more correctly by the blood water content measuring means which a dialysis apparatus has. That is, when water is removed, a part of the water in the blood is removed from the blood in the dialyzer at the set water removal speed. As a result, an osmotic pressure gradient is generated, and therefore water outside the blood vessel is guided into the blood. This is called a refilling process, and the filling rate during this refilling process is called the refilling rate. If the water removal rate is close to the refill rate, the refill process should be well balanced and the blood water content should be stable and unchanging.
However, for example, if the water removal rate is faster than the refill rate, the refill process is unbalanced and the blood water content is reduced. When such a state occurs abruptly, the aforementioned undesirable symptoms (shock symptoms) are likely to occur. That is, according to the present invention, by continuously monitoring the amount of water in the blood and controlling the amount of water to be removed and the rate of water removal, as well as the blood pump flow rate for determining the blood flow rate in the extracorporeal circuit, shock symptoms Safe dialysis can be performed without causing dialysis.
In addition, if the measured value of blood water content is considered to be a dangerous sign (such as a decrease in blood water content) that can lead to shock symptoms, blood The necessity can be notified to the hospital staff by a notification means such as an alarm buzzer. The value for generating this alarm or the like can be arbitrarily set. In addition, when devices for performing blood pressure monitoring and replacement fluid are already installed, it is also possible to send a signal to these devices to automatically measure blood pressure or perform replacement fluid. It is also possible to incorporate a sphygmomanometer or a fluid replacement device in the dialysis machine. Furthermore, by monitoring the recirculation of blood, it can contribute to obtaining accurate biological information and preventing a decrease in dialysis efficiency.

The schematic diagram of the dialysis apparatus by this invention is shown. An explanatory view of recirculation in dialysis is shown. The block diagram regarding the control by this invention is shown.

  The present invention will be described below with reference to illustrated embodiments. The present invention is achieved by the configuration of the schematic diagram shown in FIG. 1 in FIG. 1 shows a dialysis device, a dialysis fluid circuit comprising a dialysis machine 2, a dialyzer 6, a fresh dialysate circuit 4 for supplying dialysate to the dialyzer, and a used dialysate circuit 5 through which the dialysate returning from the dialyzer flows. It consists of an arterial extracorporeal circuit 7 for guiding the patient's blood from the dialysis patient 16 to the dialyzer 6, an extracorporeal circuit comprising the venous extracorporeal circuit 8 for returning the dialyzed blood from the dialyzer 6 to the patient, and the like. The dialysis machine 2 includes a dialysis machine control unit 3 including blood water content measuring means.

Dialysis means that the dialysate sent from the dialyzer 2 and the blood derived from the patient come into contact with each other through a semipermeable membrane provided in the dialyzer 6, thereby causing an osmotic pressure difference between the dialysate and the blood. It allows the movement and exchange of substances. In addition, by causing a pressure difference between the dialysate and the blood, water in the blood is also moved to the dialysate side, and as a result, water is removed from the patient. (Water removal)
First, the dialysis machine 1 will be described in detail. The dialysis machine 1 is generally divided into a personal dialysis machine and a dialysis monitoring machine. A personal dialysis machine is a dialysis monitoring device added with a function of preparing dialysate.
Preparation of dialysate is a concentrated solution containing sodium, calcium and magnesium (hereinafter referred to as “A solution”) and a bicarbonate-containing concentrated solution (hereinafter referred to as “B solution”) mixed with water to obtain an appropriate concentration and temperature. That means.

  In a dialysis machine that does not have a dialysate preparation function, that is, a dialysis monitoring device, a dialysis fluid that is mixed and diluted and adjusted to an appropriate concentration and temperature in a device generally called a dialysis fluid supply device for dialysis is used. The dialysis solution is received and the dialysis solution is used for dialysis. Moreover, in a personal dialysis machine, a dialysate is prepared by supplying A liquid, B liquid, and water for dilution, and dialysis is performed using it. These circuits for supplying water and dialysate to the dialysis machine 2 are not shown. Moreover, although both the personal dialysis apparatus and the monitoring apparatus for dialysis usually have a discharge port for discharging the used dialysate after dialysis, this is not shown. Further, since the other points are substantially the same in both dialysis machines, the other points will be described as having the same function.

The dialysis machine 1 includes a blood water content measuring means, a temperature setting mechanism including a temperature sensor for monitoring and adjusting the temperature of the dialysate, a control means for the flow rate of the dialysate flowing into the dialyzer 6, and further in the dialyzer 6 There is provided a water removal mechanism or the like that creates a pressure difference between the blood and the dialysate to transfer the water in the blood to the dialysate side. Various mechanisms have been studied for this water removal mechanism, but are not particularly limited. Examples include a viscous chamber system, a pump that uses a pump called a dual-type pump, a system that uses a chamber having a partition wall, and performs direct water removal using a water removal pump. With the recent development of technology, if the amount of water removal per unit time is set, the water removal mechanism of the dialysis machine operates fairly accurately, and the desired amount of water removal can be obtained. The water removal mechanism is not the main point of the present invention, and the present invention can be applied to any water removal mechanism.
The dialysis machine 2 is provided with a blood pump 9 for flowing blood into the extracorporeal circuit. And the above-mentioned is equipped with the control part 3 for controlling a water removal mechanism, a blood pump, etc.

Next, blood water content and blood water content measuring means will be described in detail. This blood moisture means may be provided in the control unit 3 inside the dialysis machine 1 or may be provided outside the dialysis machine 2 as a separate device. It suffices if the measured value of the blood water amount, which will be described later, can be transmitted to the control unit 3.
Blood is usually considered to be composed of plasma and blood cell components. Furthermore, each of plasma and blood cell components contains blood protein (BP) and blood water (BW), and the ratio of blood water in the plasma and blood cell components is determined as the amount of blood water (BWC). Call. And BWC is defined like the following formula 1.
BWC = BW / (BW + BP) (Formula 1)

Usually, the BWC of dialysis patients is often 0.82 to 0.85.
However, the refilling process described above is unbalanced, especially when the water removal rate is faster than the refilling rate, i.e., the amount of BW is reduced, resulting in a decrease in the value of BWC. Therefore, if this BWC value is monitored, it is possible to monitor whether or not water removal by dialysis is correctly performed. Further, by utilizing the measured value of BWC for the water removal control of the dialyzer, water removal by dialysis can be performed correctly.

  The blood water content measuring means includes an arterial ultrasonic sensor 12 installed on the arterial extracorporeal circuit 7, a venous circuit ultrasonic sensor 11 installed on the venous extracorporeal circuit 8, and those sensors and dialysis. A sensor cable (13, 14) for electrically connecting the blood moisture measuring means of the device 2 is provided. In this embodiment, ultrasonic sensors are installed at two locations on the arterial side and the venous side in order to ensure the accuracy of the measured values, but it is also possible to perform measurement by providing ultrasonic sensors in either one. is there. However, for example, when an ultrasonic sensor is installed only on the vein side, recirculation monitoring described later is required by some other device, and when an ultrasonic sensor is installed only on the artery side, This ultrasonic sensor calibration method to be described later is limited to injection of an injection solution or the like from upstream of the ultrasonic sensor. In addition, when an ultrasonic sensor is installed only on the arterial side to measure the amount of water in the blood, the state of the blood before the water removal by the dialyzer 6 is measured, so that the blood is removed by the water removal. The effect of this cannot be immediately reflected in the measured value of the blood water content, which is not a preferable method.

Therefore, in this embodiment, a value related to the measurement of the amount of water in the blood is measured by the venous ultrasonic sensor 11 installed in the venous extracorporeal circuit 8, and the arterial supersensor installed in the arterial extracorporeal circuit 7 is measured. It is assumed that the sonic sensor 12 performs an auxiliary role for measuring the amount of water in the blood (recirculation monitoring and blood flow measurement described later).
A voltage value that can be converted into an ultrasonic transmission speed when ultrasonic waves pass through the extracorporeal circuit is measured by an ultrasonic sensor installed in the extracorporeal circuit. The voltage value (V (t)) and ultrasonic transmission speed (vb) measured by the ultrasonic sensor are:
vb = E + V (t) × D
It is known that there is a relationship. Here, E and D are constants and are conventionally known.
And the value of BWC can be measured by establishing the relationship between this measured value and BWC. For this purpose, it is necessary to obtain a conversion rate for converting the measurement value obtained from the ultrasonic sensor into BWC. This conversion rate can be obtained by providing a step of calibrating the ultrasonic sensor at the start of dialysis.

Calibration of the ultrasonic sensor during dialysis can be performed, for example, by artificially changing the BWC value of blood by a known amount by an indicator.
The method of artificially changing the BWC by a known amount includes a method of intentionally changing the water removal rate of the dialysis machine, a method of injecting an injection solution such as physiological saline into the extracorporeal circuit, and controlling the dialysis machine. For example, there is a method of generating reverse filtration in the dialyzer.
First, calibration by changing the water removal rate will be described. The blood guided from the patient by the arterial extracorporeal circuit 7 at the time of dialysis is supplied to the dialyzer with a blood flow Qb (ml / min), and the rate of Qf (ml / min) from the blood by the dialyzer (water removal rate) ) Removes moisture. For ease of calculation, the water removal rate is considered to be zero at the start of dialysis. Then, by gradually increasing the water removal rate and setting the water removal rate to Qfcal (ml / min), the blood flow that flows out of the dialyzer 6 and flows through the venous extracorporeal circuit 8 flows through the original arterial circuit 7. It changes to (Qb-Qfcal) (ml / min), which is a value obtained by subtracting the water removal rate Qfcal (ml / min) from the flowing Qb (ml / min). That is, in the blood on the outlet side of the dialyzer, the water in the blood is drawn by dehydration, so the BWC decreases. The venous side ultrasonic sensor 11 installed on the dialyzer outlet side, that is, the venous side extracorporeal circuit 8 shows the ultrasonic transmission speed of blood at the time of blood flow (Qb-Qfcal) (ml / min) after the start of water removal. The voltage value is measured, and the arterial ultrasonic sensor provided in the arterial extracorporeal circuit 7 measures the blood flow Qb (ml / min).

The conditions of blood flowing into the dialyzer 6 and blood flowing out of the dialyzer 6 are expressed as follows.
In the inflow side, that is, the arterial extracorporeal circuit 7, the blood flow is Qb (ml / min), and the ratio of the blood protein contained in the blood is BWA as the blood water at this time.
Early blood protein ratio = BP / (BP + BWa)
It is expressed.
In the outflow side, that is, the venous side extracorporeal circuit 8, the blood flow is (Qb-Qfcal) (ml / min), and the ratio of the blood protein contained in the blood is the BWcal. Then, since the amount BP of blood protein does not change by dehydration,
Proportion of blood protein after dehydration = BP / (BP + BWcal)
It is expressed.
And between these, the relationship of following Formula is formed from the relationship of the mass balance in the blood which passes the dialyzer 6. FIG.
Qb × BP / (BP + BWa) = (Qb−Qfcal) × BP / (BP + BWcal)
When this equation is transformed as follows,
(BP + BWcal) / (BP + BWa) = 1−Qfcal / Qb
And
1- (BP + BWcal) / (BP + BWa) = Qfcal / Qb
And then
(BWa-BWcal) / (BP + BWa) = Qfcal / Qb
And disassembling this,
BWa / (BP + BWa) −BWcal / (BP + BWa) = Qfcal / Qb
It becomes.
Substituting BWcal = BWCcal × (BP + BWcal) obtained by modifying BWCa = BWa / (BP + BWa) and BWCcal = BWcal / (BP + BWcal)
BWCa−BWCcal × (BP + BWcal) / (BP + BWa) = Qfcal / Qb (Formula 2)

Here, when the change in the water removal rate Qf (ml / min) is smaller than the blood flow Qb (ml / min), BWa≈BWcal, and (BP + BWcal) / (BP + BWa) in (Expression 2) above. Since the value of the term is ≈1, Equation 2 is
BWCa-BWCcal = Qfcal / Qb
Can be approximated. Here, if BWCa-BWCcal is delta BWCcal,
BWCa-BWCcal = Delta BWCcal = Qfcal / Qb (Formula 3)
It becomes. From Equation 3, it is shown that the amount of change in BWC on the vein side can be estimated from the ratio of Qfcal and Qb. Here, as the blood flow Qb (ml / min), a value measured by the arterial ultrasonic sensor 12 provided on the artery side may be used, or the blood pump 9 controlled by the control unit 3 of the dialysis machine 2 may be used. A flow rate may be used. However, it is preferable to use the value of Qb (ml / min) obtained by the arterial ultrasonic sensor 12. The reason for this will be described later. The Qfcal value uses a set value for the water removal rate of the dialysis machine.
And the relationship between the BWC change of the blood after passing through the dialyzer 6, the water removal speed, and the blood flow change is obtained.
From this equation, the conversion rate for converting the measured value of the voltage of the ultrasonic sensor into BWC can be obtained. If the conversion factor is K and the change in voltage, which is the measurement value of the ultrasonic sensor, is delta Vcal,
Delta BWCcal = K x Delta Vcal (Formula 4)
That is, the blood water content BWC (t) at the time of measurement is BWC (t) = K × V (t) (Formula 5)
It can be expressed. Here, V (t) represents a voltage value measured by an ultrasonic sensor measured at a certain time.
Substituting Equation 4 into Equation 3 above yields K × delta Vcal = Qfcal / Qb,
That is, K = (Qfcal / Qb) / delta Vcal (Formula 6)
It becomes. Accordingly, the blood flowing through the extracorporeal circuit is dehydrated at a certain known water removal rate Qfcal, and the difference between the voltage values indicating the ultrasonic voltage velocity of the blood before and after the water removal is obtained. Thus, it was shown that the value of the conversion factor K can be obtained.

Next, a method of calibrating the ultrasonic sensor by injecting a known amount of infusion into the extracorporeal circuit upstream of the ultrasonic sensor and intentionally changing the BWC value will be described. The infusion solution is not particularly limited as long as it is a liquid that does not affect the human body even when injected into blood, which is generally known as an isotonic solution or a hypertonic solution. For example, physiological saline or dialysis replacement fluid Etc. Then, the injection of the injection solution may be performed manually or automatically using a liquid injection pump such as a syringe pump. In FIG. 1, the injection liquid injection means 10 is illustrated. The position for injecting the injection solution needs to be changed depending on the position where the ultrasonic sensor is attached. However, when the vein-side ultrasonic sensor 11 is calibrated, the blood flow of the vein-side ultrasonic sensor 11 is upstream. When calibrating the venous injection position 19 or the arterial ultrasonic sensor 12, this is the arterial injection position 20 upstream of the arterial ultrasonic sensor 12. Also, by controlling the dialysis machine 2 and performing reverse filtration of the dialysate in the dialysate circuit (4, 5) via the dialyzer 6, the same result as injecting the above-mentioned infusion can be obtained. You can also. Reverse filtration means that the dialysate in the dialysate circuit is caused to flow into the blood side through the hollow fiber membrane provided in the dialyzer 6.
When these injections are injected into the extracorporeal circuit and the BWC value is intentionally increased by a known amount, the conversion rate is calculated according to the same relational expression as when the water removal rate is changed. K can be determined.

  However, when the injection solution is injected from the outside, the measurement value of the ultrasonic sensor is affected by the temperature as described above. Therefore, when the injection solution is injected, the temperature of the injection solution becomes the blood temperature. It is necessary to adjust so that it becomes. For this purpose, a temperature control device such as a heater capable of adjusting the injection solution to a set temperature may be used. However, when reverse filtration of dialysate is used as an indicator, such a procedure is not necessary because dialysate whose temperature has already been adjusted is injected into the extracorporeal circuit.

That is, the blood water content (BWC) is measured through the following steps according to the present embodiment.
1. The ultrasonic sensor (11 and 12) is installed in the extracorporeal circuit (7, 8) used for dialysis, and the ultrasonic characteristics of blood flowing through the extracorporeal circuit (7, 8) (the ultrasonic transmission speed and voltage in the blood). Is output as a value).
2. During dialysis, the value of BWC is intentionally changed upstream of the venous ultrasonic sensor 11. This variation may be a variation due to an intentional change in the water removal rate by the dialysis device, or may be a variation caused by injecting a known amount of infusion solution such as physiological saline upstream of the ultrasonic sensor. Moreover, the same result as inject | pouring injection liquids, such as a physiological saline, can be obtained by performing reverse filtration using a dialyzer and a dialysis apparatus.
The BWC is obtained from the voltage measurement value of the venous ultrasonic sensor 11 from the amount of change of the measurement value of the ultrasonic sensor measured by the intentional fluctuation of BWC in 3.2 using the above-described calculation formula (Formula 6). The conversion rate K is calculated. The value of blood flow Qb necessary for Equation 6 is measured by the arterial ultrasonic sensor 12.
4). And 3. The value of BWC is obtained using the conversion rate K obtained in step 1 and Equation 5. Further, the rate of change of BWC may be obtained using the initial voltage value Va by the ultrasonic sensor in the initial stage of dialysis and the subsequent measured voltage value. The calculation formula in the case of the rate of change of BWC (BWCv% (t)) is as follows. When the initial voltage is Va, and each measured value after every predetermined time is V (t),
BWCv% (t) = K × (V (t) −Va) × 100 (Formula 7)
It becomes. These calculations are performed by the blood water content measuring means.
In this way, by monitoring the blood water content continuously at predetermined time intervals, and monitoring the rate of change of blood water content at the time of dialysis from the measured values at that time, rapid changes can be made. If the water removal mechanism of the dialysis machine is controlled so that it does not occur, or if a sphygmomanometer is built in the dialysis machine, the blood pressure is automatically measured. Notify hospital staff of the need for measurement, or if a dialysis machine is equipped with a fluid replacement device, automatically perform a prescribed amount of fluid replacement, or notify the hospital staff of the need for fluid replacement I can do it.

The above contents will be further described with reference to FIG.
In FIG. 3, the dialysis machine 2 and the control part 3 are typically shown. The control unit 3 includes a dialysis device control unit 3A that controls the dialysis device and a blood water content measuring unit 3B. In FIG. 3, the dialysis device control unit 3A and the blood water content measuring means 3B are shown as separate units, but it is also possible to incorporate the blood water content measurement unit 3B in the dialysis device control unit 3A. Further, the dialyzer 2 generally includes the control unit 3 therein, but for convenience of explanation, the control unit is set as the control unit 3 and receives a control signal to actually perform dialysis operation such as water removal, The part provided with the means for measuring the temperature of dialysate or the like will be described as the dialysis machine 2.
First, the above-described calibration of the ultrasonic sensor (not shown) provided in the blood water content measuring means 3B is performed, and the conversion rate K for obtaining the BWC value is obtained from the measured value of the ultrasonic sensor at the time of calibration. The blood water content measuring means 3B is used to generate a deliberate change in the known amount of the blood water content BWC of the blood in the venous extracorporeal circuit (not shown, see 8 in FIG. 1). The measuring means control output circuit 35 and below are simply called the output circuit 35. ) To output an ultrasonic sensor calibration signal to the dialysis machine controller 3A.
In response to this, the dialyzer control unit 3A generates a signal for injecting the infusate into the extracorporeal circuit by the infusate injecting means 10 in order to generate an intentionally known change in the BWC, or the dialysis machine 2 The water removal control signal for changing the water removal speed and the temperature setting change signal for changing the dialysate temperature are output. As described above, these can cause a change in BWC to obtain a conversion rate K by any method. Moreover, when changing the known amount of BWC by injection | pouring of an injection liquid, it is also possible by the injection | pouring of the injection liquid by a hospital staff.

Then, values (water removal rate and dialysis temperature) necessary for calibration of the ultrasonic sensor of the blood water content measuring means are obtained from the dialysis machine output signal circuit 30 of the dialysis machine 2 via the dialyzer control unit 3A. The amount is input to the amount measuring means 3B via the blood water amount measuring means control input circuit 29.
Based on these values and blood flow measured by an arterial ultrasonic sensor (not shown, see 12 in FIG. 1) provided in the arterial extracorporeal circuit (not shown, see 7 in FIG. 1), The moisture content measuring means 3B obtains the conversion rate K described above.
When an intentional change of the BWC performed for the calibration is generated, the arterial ultrasonic sensor (not shown in FIG. 1; 7 in FIG. 1) of the blood moisture measuring means 3B provided in the arterial extracorporeal circuit. In the case of (see), if a change in measured value (voltage value) related to BWC is observed, recirculation is suspected. The recirculation will be described later. Therefore, in such a case, the above-described output circuit 35 is used to output a recirculation notification signal to the dialysis machine control unit 3A of the dialysis machine 2. Accordingly, the dialysis machine control unit 3A can notify the hospital staff of the recirculation status using the alarm means 32. Even if recirculation is not detected or occurrence of recirculation is detected, a procedure for improving recirculation is performed, and if recirculation is improved, blood water content can be measured.

  When recirculation does not occur and the conversion rate K is obtained, a voltage value indicating the ultrasonic transmission speed of blood is periodically measured by a vein-side ultrasonic sensor thereafter to obtain a BWC value. . The BWC value obtained here is output to the dialyzer control unit 3A using the blood water content measurement value output circuit 28. Then, the dialysis machine control unit 3A that has input the value of BWC performs water removal at an appropriate water removal rate Qf on the dialysis machine 2 while comparing the value with the value of BWC at the start of dialysis. As shown, the dialysis machine control circuit 31 is used to output a water removal control signal to control the water removal speed.

  In addition, even if water removal is performed at an appropriate water removal rate by monitoring the BWC, if a symptom such as a sudden decrease in BWC is confirmed due to a change in the condition of the patient, the dialyzer control unit 3A, for example, issues an alarm buzzer using the alarm means 32, notifies the hospital staff, automatically measures blood pressure using the blood pressure monitor 33, or uses the fluid replacement device 34 to automatically supply fluid replacement to the extracorporeal circuit. It is possible to perform treatment such as performing it automatically. It is also possible to output a control signal from the dialysis machine control unit 3A to the dialysis machine 2 to change the water removal rate or the blood flow rate by the blood pump.

  In the present invention, an ultrasonic sensor is provided in the extracorporeal circuit in order to measure the ratio BWC of blood water content, and the voltage value is measured by the ultrasonic sensor in order to obtain the ultrasonic transmission speed of blood. However, this voltage value is known to be very sensitively affected by the temperature of the blood being measured. That is, it is necessary to correct the voltage value according to the blood temperature. Therefore, it is necessary to accurately measure the temperature of blood to be measured. This correction value is determined by the blood temperature and needs to be added to the voltage value measured by the ultrasonic sensor each time. The blood temperature for determining the correction value may be provided with a temperature sensor that measures the blood temperature in the vicinity of the ultrasonic sensor. However, when the temperature sensor is directly contacted with blood, the temperature sensor is used. The temperature sensor that measures blood surface contamination and the surface temperature of the extracorporeal circuit is located in the indoor space, so the effects of room temperature and ambient temperature (heat generated by the dialyzer, etc.) It was difficult to measure the blood temperature accurately. Furthermore, when measuring blood temperature indirectly from outside the extracorporeal circuit, the measurement results are affected by the shape and material of the extracorporeal circuit, so to solve this, a dedicated extracorporeal circuit or A member for temperature measurement may be required. However, in the present invention, since the measured value of the temperature sensor that measures the temperature of the dialysate provided in the dialyzer is used, no special member is required for the extracorporeal circuit. Therefore, in the present invention, a generally used extracorporeal circulation circuit for dialysis can be used.

  The blood flowing in the extracorporeal circuit comes into contact with the dialysate through the semipermeable membrane of the dialyzer. At this time, heat exchange is performed simultaneously with dialysis. This heat exchange is usually performed on the basis of the dialysate side having a high flow rate. That is, it can be considered that the temperature of the blood after passing through the extracorporeal circuit and passing through the dialyzer is equal to the temperature of the dialysate. By using the dialysate temperature for the temperature correction of the ultrasonic sensor, it becomes possible to make an accurate correction that is not available in the prior art, and furthermore, the temperature sensor originally provided in the dialysis machine can be diverted. There is also an advantage that a separate temperature sensor is not required just to compensate for the above.

  Furthermore, the measurement value by the ultrasonic sensor is affected by the temperature of the blood, the blood flow, and the amount of water in the blood, and the measurement value of the ultrasonic sensor can be corrected by taking them into consideration. It is clear from. That is, in addition to the above-mentioned calibration of the water content measurement means by means such as changing the water removal rate and injecting the liquid into the extracorporeal circuit, the temperature of the dialysate flowing through the dialysate circuit by the dialysis machine is intentionally set. The blood water content measuring means can also be calibrated by changing the temperature of the blood to change the temperature of the blood through heat exchange with the blood by the dialyzer.

  In this embodiment, the arterial extracorporeal circuit 7 is also provided with an arterial ultrasonic sensor 12. The arterial ultrasonic sensor 12 can detect recirculation. The recirculation will be described with reference to FIG. In FIG. 2, reference numeral 23 denotes a patient's blood vessel, 17 denotes a puncture site to the patient on the artery side, 18 denotes a puncture site to the patient on the vein side, 26 denotes a venous side puncture needle, and 27 denotes an arterial side puncture needle. Reference numeral 7 is the arterial extracorporeal circuit shown in FIG. 1, and 8 is also the venous extracorporeal circuit shown in FIG. Usually, the patient's blood led by the arterial puncture needle 27 is sent to a dialyzer (not shown) through the arterial extracorporeal circuit 7.

  The blood that has been dialyzed through a dialyzer (not shown) passes through the venous extracorporeal circuit 8, is returned to the patient's blood vessel 23 by the venous puncture needle 26, and flows along the blood flow 24 inside the blood vessel. Circulate in the patient's body. However, due to some pressure in the blood and the characteristics of the fluid, a portion of the blood after dialysis that has returned from the vein side into the body is again sucked into the arterial puncture needle 27 as indicated by 25, and the dialyzer passes through the artery side of the extracorporeal circuit. May flow into. This is called recirculation. Even if the blood water content is measured in a state where the ratio of the recirculating blood is high, it cannot be said that it indicates the true blood water content of the patient. This is because the blood water content of blood after passing through the dialyzer has become a low value due to water removal, and the blood with low blood water content flows into the dialyzer again as it is, and the water content is further removed. The value of water content in the blood is lowered. Therefore, in such a state, even if the blood water content is measured, the value is meaningless.

  Usually expressed as a percentage of the blood flow through the recirculation or extracorporeal circuit. What is necessary is just to set the allowable value of the ratio. If recirculation is detected and the rate of circulation is confirmed to be higher than the permissible value, it is possible to stop the measurement of the water content in the blood. It is also possible to notify the hospital staff using known alarm means such as an alarm buzzer. This notification to the hospital staff can also be used to reduce the recirculation procedure, and if this reduces and improves the rate of recirculation, dialysis can be performed while monitoring the blood water level without any problems. It becomes. Also, if the percentage of recirculating blood is too high, the same blood will pass through the dialyzer many times, resulting in incomplete dialysis efficiency for the patient. By monitoring the occurrence of such recirculation, it is possible not only to accurately measure the blood water content, but also to monitor the decrease in dialysis efficiency of the patient.

  As a method for monitoring recirculation, a method of intentionally changing blood in the downstream of the arterial ultrasonic sensor 12 can be considered. In the present invention, the presence or absence of recirculation is also confirmed by changing the water removal rate used for the calibration of the ultrasonic sensor described above, or by intentionally changing the amount of water in the blood by injecting an infusion solution or performing reverse filtration. I can do it. That is, the change in the blood water amount, which is confirmed by the vein-side ultrasonic sensor 11 at the time of calibration of the blood moisture measuring means, that is, the change in the voltage value measured by the ultrasonic sensor is not significantly reduced. If it can be confirmed by the side ultrasonic sensor, it can be said that it is recirculating. Therefore, by monitoring this, it becomes possible to detect recirculation.

The arterial ultrasonic sensor 12 is also used to measure the blood flow Qb flowing through the extracorporeal circuit. Measurement of blood flow with an ultrasonic sensor is conventionally known and will not be described in detail.
It is also possible to use the value of the flow rate of the blood pump indicated by the control unit 3 of the dialyzer as the value of Qb in the above equation 3. However, since the blood flow of the blood that is actually flowing can be measured by measuring the blood flow rate with an ultrasonic sensor provided on the artery side, the reliability of the measured value of the water content in the blood is increased. This is because the flow rate of the blood pump indicated by the control unit 3 may not represent the blood flow flowing through the actual extracorporeal circuit. For example, even when the puncture needle is clogged, thereby causing a stagnation in the blood flow and the blood flow rate flowing through the extracorporeal circulation circuit is reduced, the control unit 3 of the dialysis device uses the theoretical blood pump as the value of Qb. Shows the flow rate. That is, it is possible to use a value different from the actual blood flow rate as Qb.

DESCRIPTION OF SYMBOLS 1 Dialysis machine 2 Dialysis machine 3 Control part 3A Dialyzer control part 3B Blood water content measuring means 4 Fresh dialysate circuit 5 Used dialysate circuit 6 Dialyzer 7 Arterial side extracorporeal circuit 8 Vein side extracorporeal circuit 9 Blood pump 10 Infusion solution injection means 11 Venous side ultrasonic sensor 12 Arterial side ultrasonic sensors 13 and 14 Sensor cable 15 Blood pump cable 16 Patient 17 Arterial side puncture site 18 Venous side puncture site 19 Venous side injection location 20 Arterial side injection location 21 An arrow 22 indicating the flow direction An arrow 23 indicating the flow direction of the dialysate 24 A blood vessel in the patient 24 An arrow indicating the direction of blood flow in the blood vessel 25 An arrow 26 indicating the flow of recirculating blood A venous puncture needle 27 An artery Side puncture needle 28 Blood water content measurement value output circuit 29 Blood water content measurement means control input circuit 30 Dialysis device output signal circuit 31 Device control circuit 32 alarm means 33 sphygmomanometer 34 replacement fluid device 35 blood water content measuring means control the output circuit

Claims (12)

  A blood water content measuring means capable of monitoring the value of blood water in the blood flowing through the dialyzer, the extracorporeal circuit, the dialysis device, the dialysate circuit, and the extracorporeal circuit during dialysis and / or the change in the blood water content is provided. A dialysis machine characterized by that.   The dialysis apparatus according to claim 1, further comprising means for detecting recirculation of blood circulating outside the body.   The dialysis apparatus according to claim 1 or 2, further comprising a calibration means for calibrating the blood water content measurement means.   The dialysis apparatus according to claim 3, wherein the calibration means of the blood water content measuring means is based on a change in the water removal rate by a dialysis machine.   The dialysis apparatus according to claim 3, wherein the calibration means of the blood water content measuring means is a water content increasing means for increasing the water content of blood flowing through the extracorporeal circuit by a known amount.   6. The dialysis apparatus according to claim 5, wherein the moisture amount increasing means is means for injecting an injection solution into the extracorporeal circuit.   The dialysis apparatus according to claim 6, wherein the moisture amount increasing means includes a temperature adjusting means for adjusting the injected liquid to a predetermined temperature.   The dialysis apparatus according to claim 5, wherein the moisture amount increasing means is a means by reverse filtration to an extracorporeal circuit using a dialysis machine and a dialyzer.   The calibration means of the blood water content measuring means intentionally changes the temperature of the dialysate flowing through the dialysate circuit by a dialysis machine, thereby causing a substantially equivalent change in the temperature of the blood flowing through the extracorporeal circuit. The dialysis device according to claim 3, wherein   The dialysis machine further includes a temperature sensor for measuring the temperature of the dialysate flowing through the dialysate circuit, and a correction means for correcting the value obtained from the blood water content measurement means according to the measurement value obtained from the temperature sensor. The dialysis apparatus according to any one of claims 1 to 9, wherein the dialysis apparatus is provided.   The blood moisture measuring means has an ultrasonic sensor, and the ultrasonic sensor is installed in an arterial extracorporeal circuit and a venous extracorporeal circuit relative to the heart of the extracorporeal circuit. The dialysis device according to 1.   The dialysis apparatus according to claim 11, wherein the ultrasonic sensor provided in the arterial extracorporeal circuit measures the flow rate of blood flowing in the extracorporeal circuit.

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