JP2022055755A - Blood flow measuring method, dialysis device and program - Google Patents

Abstract

To provide a technology for accurately measuring a blood flow rate in extracorporeal blood circulation.SOLUTION: A dialysis unit 100 includes pressure gauges 131, 132 for measuring a pressure of blood flowing through an artery side blood circuit 110. A controller 200 measures a blood flow rate in the artery side blood circuit 110 following Hagen-Poiseuille law by utilizing a measurement result of the pressure gauges 131, 132. A viscosity coefficient according to the Hagen-Poiseuille law may be derived by using a measurement result of a concentration measuring apparatus 101.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to the measurement of flow rate in blood circulation outside the body.

Conventionally, various techniques have been proposed for blood circulation outside the body in dialysis treatment and the like. For example, Republished 2015-141621 (Patent Document 1) discloses a hemodialysis system that utilizes a blood pump in blood circulation outside the body. In conventional dialysis treatment, a set value of the amount of liquid sent by a pump that sends blood may be adopted as the blood flow rate.

Republished 2015 No. 141621

In dialysis treatment, blood flow rate is one of the important measurement items included in the prescription. Therefore, there is a need for a technique for more accurately measuring the blood flow rate.

The present disclosure has been conceived in view of such circumstances, and an object thereof is to provide a technique for accurately measuring blood flow rate in blood circulation outside the body.

According to certain aspects of the present disclosure, a method performed by a computer, the first in an arterial blood circuit for inflowing blood into a blood purifier or a venous blood circuit for draining blood from a blood purifier. Steps to obtain the difference in blood pressure at each of the 1st and 2nd points, the pressure difference, the index of blood viscosity, the distance between the 1st and 2nd points, and the blood circuit on the arterial side. Alternatively, a blood flow measuring method is provided comprising a step of obtaining a blood flow rate in the arterial side blood circuit or the venous side blood circuit based on the diameter of the venous side blood circuit.

Both the first and second locations may be located on one side of the blood purifier.

The blood flow rate measuring method is a step for malfunction when the difference between the set value of the amount of liquid to be sent and the blood flow rate in the blood pump that sends blood in the arterial side blood circuit and the venous side blood circuit is equal to or more than a given threshold value. May be further equipped with steps to perform.

The blood pump may be configured to pump blood in the arterial blood circuit. The first and second sites may be located on the arterial blood circuit.

The step of obtaining blood flow may include obtaining an index of blood viscosity based on the blood concentration measured in the arterial or venous blood circuit.

According to other aspects of the present disclosure, a blood purifier, an arterial blood circuit for inflowing blood into the blood purifier, a venous blood circuit for draining blood from the blood purifier, and an arterial blood circuit. A dialysis apparatus is provided that comprises a blood pump that pumps blood from the venous blood circuit and a controller that controls the operation of the blood pump, the controller being configured to carry out the blood flow measurement method described above. To.

According to yet another aspect of the present disclosure, a program is provided that, when performed by a computer, causes the computer to perform the blood flow measurement method described above.

According to the present disclosure, the flow rate of blood is measured using the pressure of blood at two points in the blood circuit.

It is a figure which shows an example of the structure of a dialysis machine. It is a figure which shows the formula for obtaining the blood flow rate Q according to Hagen-Boazille's law. It is a flowchart of an example of the process performed by the controller 200 for measuring the flow rate of blood in a dialysis unit 100.

Hereinafter, an embodiment of the dialysis machine will be described with reference to the drawings. In the following description, the same parts and components are designated by the same reference numerals. Their names and functions are the same. Therefore, these explanations will not be repeated.

[1. Configuration of dialysis machine]
FIG. 1 is a diagram showing an example of the configuration of a dialysis machine. As shown in FIG. 1, the dialysis machine 1 includes a dialysis unit 100 and a controller 200.

(Dialysis unit 100)
The dialysis unit 100 includes a dialyzer 103, an arterial blood circuit 110 connecting the patient's artery and the dialyzer 103, and a venous blood circuit 120 connecting the patient's vein and the dialyzer 103. The dialyzer 103 is an example of a blood purifier. The dialysis device 1 further obtains a blood pump 102 that sends blood to the dialyzer 103 in the arterial blood circuit 110, a concentration measuring device 101 that measures the blood concentration in the arterial blood circuit 110, and a blood concentration in the venous blood circuit 120. Includes a concentration measuring device 104 for measuring.

The dialysis machine 1 further includes a water removal mechanism 150, which is a mechanism for supplying dialysate to the dialyzer 103. In the water removal mechanism 150, the dialysate is supplied to the dialyzer 103 via the upstream dialysate line 151, and the dialysate is discharged from the dialyzer 103 via the downstream dialysate line 152. The water removal mechanism 150 includes a dialysate pump 155 that promotes the discharge of dialysate from the dialyzer 103. Various supply methods can be adopted as the dialysate supply method by the water removal mechanism 150.

The dialysis machine 1 further includes pressure gauges 131 and 132. The pressure gauges 131 and 132 are both arranged on the arterial blood circuit 110 so as to measure the pressure of the blood flowing through the arterial blood circuit 110.

The pressure gauge 131 is arranged on the upstream side of the concentration measuring device 101. The pressure gauge 132 is arranged on the downstream side of the concentration measuring device 101. As a result, the distance between the pressure gauge 131 and the pressure gauge 132 can be set long while suppressing the increase in size of the dialysis unit 100 as much as possible.

The pressure gauges 131 and 132 may be arranged on the venous side blood circuit 120. It is preferable that both the pressure gauge 131 and the pressure gauge 132 are arranged so as to measure the pressure of blood flowing to one side of the arterial blood circuit 110 or the venous blood circuit 120. That is, it is preferable that the measurement position of the pressure gauge 131 and the measurement position of the pressure gauge 132 are arranged so as not to sandwich the dialyzer 103. As a result, it is possible to avoid that the difference in the measurement results between the pressure gauge 131 and the pressure gauge 132 reflects the effects of howling by the dialyzer 103 and clogging in the dialyzer 103.

(Controller 200)
The controller 200 includes a processor 201, a storage device 202, an input device 203, an output device 204, and an input / output interface 205.

Processor 201 executes a program stored in storage device 202 or stored in external storage device. The storage device 202 is composed of a hard disk drive, a solid state drive, or the like. The storage device 202 may store various data used for executing the program.

The input device 203 is used by the user to input information into the dialysis device 1, and is realized by, for example, a keyboard, a mouse, hardware buttons, and / or a touch sensor.

The output device 204 is used to output information from the dialysis device 1 and is implemented by, for example, a display, a Light Emitting Diode (LED) lamp, and / or a speaker.

The input / output interface 205 is an interface for outputting data from each element in the dialysis unit 100 to the controller 200 and outputting data from the controller 200 to each element in the dialysis unit 100. In one example, the controller 200 outputs control instructions to the blood pump 102 via the input / output interface 205. In another example, the controller 200 acquires the measurement results from the concentration measuring devices 101 and 104 and the pressure gauges 131 and 132, respectively, via the input / output interface 205.

In the present embodiment, the controller 200 controls the dialysis unit 100 and measures the blood flow in the dialysis unit 100 by using the measurement results of the pressure gauges 131 and 132. The controller 200 may notify if there is a discrepancy between the measured blood flow and the set value of the amount of blood sent by the blood pump 102 in a unit time. In this sense, the pressure gauges 131 and 132 are preferably arranged so as to measure the pressure of blood at a position on the same side as the side where the blood pump 102 is arranged with respect to the dialyzer 103.

[2. Measurement of blood flow using pressure measurement results at multiple positions]
Next, the measurement of the blood flow rate using the measurement results of the pressure gauges 131 and 132 in the dialysis apparatus 1 will be described. In the following description, the names of physical quantities related to the dialysis machine 1 are defined as follows.

“Px” represents the measurement result of the pressure gauge 131.

“Py” represents the measurement result of the pressure gauge 132.

“R” represents the diameter of the circuit (arterial blood circuit 110 or venous blood circuit 120) in which the pressure gauges 131 and 132 are arranged.

"Η" is a viscosity coefficient of blood and represents the viscosity coefficient used in Hagen-Poiseuille's law.

“L” represents the distance between the measurement position of the pressure gauge 131 and the measurement position of the pressure gauge 132 in the arterial blood circuit 110 or the venous blood circuit 120.

FIG. 2 is a diagram showing an equation for obtaining a blood flow rate Q according to Hagen-Boazeuil's law. In the formula (1) shown in FIG. 2, the blood flow rate Q is represented by the above-mentioned “Px”, “Py”, “r”, “η” and “l” and the pi. The values of "r" and "l" may be stored in the storage device 202 in advance.

The controller 200 converts the blood concentration measured by the concentration measuring device 101 or the concentration measuring device 104 into "η" of the formula (1) according to a known relationship. When the pressure gauges 131 and 132 are arranged to measure the pressure of blood on the blood circuit 110 on the arterial side, the controller 200 uses the measurement result of the concentration measuring device 101 to derive "η". When the pressure gauges 131 and 132 are arranged to measure the pressure of blood on the venous blood circuit 120, the controller 200 utilizes the measurement result of the concentration measuring device 104 for deriving the “η”.

[3. Processing flow]
FIG. 3 is a flowchart of an example of a process executed by the controller 200 for measuring the flow rate of blood in the dialysis unit 100. The controller 200 starts the process of FIG. 3, for example, with the start of dialysis treatment. The controller 200 may realize the process of FIG. 3 by causing the processor 201 to execute a given program. The controller 200 may include a dedicated circuit such as an ASIC (application specific integrated circuit) or an FPGA (field-programmable gate array) that executes the process of FIG.

With reference to FIG. 3, in step S100, the controller 200 acquires the measurement results (Px and Py) of the pressure gauges 131 and 132 and the measurement results (Ht) of the concentration measuring device 101 (or the concentration measuring device 101). ..

In step S102, the controller 200 converts the measurement result (Ht) of the blood concentration acquired in step S100 into the viscosity coefficient η, and then derives the blood flow rate Q according to the equation (1).

In step S104, the controller 200 stores the flow rate Q derived in step S102 in the storage device 202.

In step S106, the controller 200 acquires the flow rate BP of the blood pump 102 (for example, a set value for the blood pump 102), compares the flow rate BP with the flow rate Q derived in step S102, and gives these differences. It is judged whether or not it is equal to or more than the threshold value of. If the difference is less than the threshold value (NO in step S106), the controller 200 proceeds to control to step S108, and if the difference is equal to or more than the threshold value (YES in step S106), the controller proceeds to control to step S110.

The threshold value can be appropriately set in the field where the dialysis machine 1 is used. The threshold value may be set based on the value of the flow rate Q derived in step S102. In one example, a value of 10% of the value of the flow rate Q may be set as the threshold value. In this case, if the flow rate BP has a difference of 10% or more with respect to the flow rate Q, the control proceeds to step S110.

In step S108, the controller 200 determines whether or not a certain time (for example, 1 minute) has elapsed since the measurement result was acquired in step S100, and if it is determined that a certain time has elapsed, the controller 200 controls to step S100. return. As a result, the control of steps S100 to S108 is repeated at regular intervals while the difference between the flow rate Q and the flow rate BP is less than the threshold value.

In step S110, the controller 200 stops the blood pump 102.

In step S112, the controller 200 stops the dialysate pump 155.

In step S114, the controller 200 notifies the abnormality of the blood pump 102 and ends the process of FIG. The notification may be display and / or audio output by the output device 204, or may be a notification to an external device (for example, a communication device carried by a medical worker), or a combination thereof. There may be.

In the process described above, the controller 200 stores the flow rate Q (at regular time intervals) in the storage device 202 in step S104. In step S104, the controller 200 stores the flow rate BP in the storage device 202 together with the flow rate Q. This allows the healthcare professional to determine whether or not the prescribed dialysis treatment has been achieved by analyzing the course of the difference between the flow rate Q and the flow rate BP, and if not. The cause can be examined.

In the process described above, the stop of the blood pump 102 in step S110, the stop of the dialysate pump 155 in step S112, and the notification in step S114 are examples of steps for malfunction.

It should be considered that each embodiment disclosed this time is exemplary in all respects and is not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims. Further, the inventions described in the embodiments and the modifications thereof are intended to be carried out alone or in combination as much as possible.

1 dialysis machine, 100 dialysis unit, 101, 104 concentration measuring device, 102 blood pump, 103 dialyzer, 110 arterial blood circuit, 120 venous blood circuit, 131, 132 pressure gauge, 150 water removal mechanism, 151 upstream side dialysate. Line, 152 downstream dialysate line, 155 dialysate pump, 200 controller.

Claims (7)

The method performed by the computer
The difference in blood pressure at each of the first and second points in the arterial blood circuit for inflowing blood into the blood purifier or the venous blood circuit for draining blood from the blood purifier. Steps to get and
The arterial blood circuit or A blood flow measuring method comprising a step of acquiring a blood flow rate in the venous side blood circuit. The blood flow rate measuring method according to claim 1, wherein both the first portion and the second portion are arranged on one side of the blood purifier. When the difference between the set value of the amount of liquid to be sent and the flow rate of the blood in the blood pump that sends the blood of the arterial blood circuit and the venous blood circuit is equal to or more than a given threshold value, the step for malfunction is executed. The blood flow measuring method according to claim 1 or 2, further comprising a step. The blood pump pumps blood in the arterial blood circuit.
The blood flow rate measuring method according to claim 3, wherein the first place and the second place are located on the arterial side blood circuit. Claims 1 to 4 include obtaining an index relating to the viscosity of the blood based on the blood concentration measured in the arterial blood circuit or the venous blood circuit. The blood flow rate measuring method according to any one of the above items. With a blood purifier,
The arterial blood circuit for inflowing blood into the blood purifier,
A venous blood circuit for draining blood from the blood purifier,
A blood pump that pumps blood from the arterial blood circuit and the venous blood circuit,
A controller that controls the operation of the blood pump is provided.
The controller is a dialysis machine configured to carry out the blood flow rate measuring method according to any one of claims 1 to 5. A program, which is executed by a computer to cause the computer to perform the blood flow rate measuring method according to any one of claims 1 to 5.

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