JP6988342B2 - Blood circuit and extracorporeal circulation device - Google Patents

Description

The present invention relates to a blood circuit, an ultrasonic flow meter, and an extracorporeal circulation device including the blood circuit and the ultrasonic flow meter, which are used in an extracorporeal circulation device for circulating a patient's blood outside the body.

Blood purification devices used for treatments such as blood dialysis, plasma exchange, and adsorption therapy, and extracorporeal circulation devices such as heart-lung machines generally send out blood circuits for flowing blood, blood purifiers such as dialyzer, and blood. Equipped with a blood pump to circulate the patient's blood outside the body.
In the extracorporeal circulation device, it is necessary to monitor the flow rate of blood flowing through the blood circuit in order to detect poor blood removal from the patient or blockage of the blood circuit due to a thrombus. Therefore, an ultrasonic sensor is used to monitor the blood flow rate (see Patent Documents 1 and 2).

When an ultrasonic sensor S is attached to a tube T constituting a blood circuit, as shown in FIG. 9, the tube does not sufficiently adhere to the wave front SF of the ultrasonic sensor S. Therefore, it is generally practiced to apply a solvent such as gel or vaseline to the contact surface between the tube T and the ultrasonic sensor S to improve the transmission of ultrasonic waves.

Japanese Unexamined Patent Publication No. 2008-0232669 Japanese Patent Application Laid-Open No. 2003-169893

However, it is complicated to apply a solvent for measuring the flow rate every time the treatment is performed using the extracorporeal circulation device. Further, if the solvent is not sufficiently applied, the adhesion between the tube T and the wave front SF of the ultrasonic sensor S cannot be ensured, which causes a decrease in the accuracy of the flow rate measurement.

Therefore, the present invention includes a blood circuit, an ultrasonic flow meter, and an extracorporeal circulation device including the blood circuit and the ultrasonic flow meter, which can measure the flow rate with high accuracy without applying a solvent such as gel or vaseline. The purpose is to provide.

The present invention has a blood pump for flowing blood and a transmitter / receiver for transmitting / receiving ultrasonic waves, and an ultrasonic flow meter for measuring the flow rate of blood in which the transmission / reception surface of the transmitter / receiver is configured by a plane. A blood circuit used in an extracorporeal circulation device including, which is connected to a blood purifier and in which the blood pump is arranged to circulate blood, and is in contact with a main tube mainly constituting the blood circuit and a wave transmitting / receiving surface. The present invention relates to a blood circuit having a flat surface portion of a tube, including a measuring tube used for measuring a flow rate, and a transmitter / receiver attached to the measuring tube.

Further, the ultrasonic flow meter has a circuit mounting portion having a pair of sensor flat portions arranged so as to sandwich the measuring tube, and a pair of wave transmission / reception portions arranged on the pair of sensor flat portions. It is preferable to provide a vessel.

Further, the measuring tube is preferably made of a soft resin having more flexibility than the main tube.

Further, the measuring tube is preferably made of a material having an ultrasonic propagation velocity of 1400 m / sec or more.

Further, it is preferable that the surface roughness of the measuring tube is Ra 1.5 μm or less.

The present invention is also used in an extracorporeal circulation device including a blood pump for flowing blood and a blood circuit in which the blood pump is arranged to circulate blood, and is an ultrasonic flow meter for measuring the flow rate of blood. A circuit mounting portion having a pair of sensor flat portions arranged so as to sandwich and face the tubes constituting the blood circuit, and a pair of transmission / reception portions arranged on the pair of sensor flat portions to transmit and receive ultrasonic waves. A wave device is provided, and the distance between the pair of sensor flat portions is a tube wall in the entire portion of the tube that comes into contact with the pair of sensor flat portions in a state where the tube is mounted on the circuit mounting portion. The present invention relates to an ultrasonic flow meter having a length in which the outer wall and the inner wall of the blood vessel are substantially parallel to each other.

Further, the circuit mounting portion further includes a base portion and a lid portion that can be opened and closed, and the base portion and the lid portion are substantially orthogonal to each other in a direction in which the pair of sensor plane portions face each other. It is preferable that the tubes are arranged so as to be able to be sandwiched and opposed to each other in the direction.

Further, it is preferable that the pair of wave transmitters and receivers are arranged at a predetermined distance with respect to the blood flow direction in the tube, and transmit and receive ultrasonic signals diagonally with respect to the blood flow direction.

Further, the present invention includes a blood purifier for purifying blood, a blood pump for flowing blood, a blood circuit connected to the blood purifier and the blood pump is arranged to circulate blood, and any of the above. The present invention relates to an extracorporeal circulation device comprising the above-mentioned ultrasonic flow meter.

Further, in the extracorporeal circulation device, the blood circuit is preferably the blood circuit according to any one of the above.

According to the present invention, since the adhesion between the blood circuit and the transmitter / receiver can be ensured, it is possible to measure the flow rate with high accuracy by the ultrasonic flow meter.

It is a schematic block diagram of the hemodialysis apparatus in 1st Embodiment of this invention. It is a block diagram of the hemodialysis apparatus in 1st Embodiment, and it is explanatory drawing of the attachment part of the ultrasonic flow meter in a blood circuit. FIG. 2 is a cross-sectional view taken along the line XX in FIG. It is explanatory drawing of the circuit mounting part of the ultrasonic flow meter in the blood circuit in the 2nd Embodiment of this invention. FIG. 4 is a sectional view taken along the line YY of the circuit mounting portion in FIG. It is explanatory drawing of the main tube and the circuit mounting part in 3rd Embodiment. 6 is a cross-sectional view taken along the line ZZ in FIG. It is sectional drawing of the circuit mounting part in the modification of this invention. It is a figure which shows the example which the parallel part of the tube outer wall and the inner wall, and a wavefront is short in the conventional example.

Hereinafter, preferred embodiments of the blood circuit of the present invention, an ultrasonic flow meter, and an extracorporeal circulation device including these will be described with reference to the drawings. In the present invention, as an example of an extracorporeal circulation device, hemodialysis is performed to purify the blood of a patient with renal failure or drug addiction, remove excess water from the blood, and replenish the blood with water as needed. The dialysis machine will be described.

Further, the hemodialysis apparatus of the present embodiment automatically performs each step such as a priming step, a blood removal step, a dialysis step, and a blood return step continuously and automatically by controlling the flow of dialysate in the blood circuit. It is an automatic hemodialysis machine.

<First Embodiment>
The overall configuration of the hemodialysis apparatus 100A of the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing a schematic configuration of a hemodialysis apparatus 100A according to the first embodiment of the present invention, and FIG. 2 is a block diagram showing a hemodialysis apparatus 100A and an attachment portion of an ultrasonic flow meter in a blood circuit. An explanatory diagram is shown.

As shown in FIGS. 1 and 2, the hemodialysis apparatus 100A includes a blood circuit 110 for flowing blood, a blood pump 111a, a blood purifier 120, a dialysate circuit 130, and a water removal / back filtration pump P1. And an ultrasonic flow meter 140A and a control device 150.

The blood circuit 110 has an arterial side line 111, a venous side line 112, a drug line 113, and a drainage line 114. Further, the arterial side line 111, the venous side line 112, the drug line 113, and the drainage line 114 constituting the blood circuit 110 are configured to include a main tube 110 m and a measurement tube 110s (see FIG. 2). ). The configuration of the main tube 110m and the measuring tube 110s will be described in detail later.

The arterial side line 111 is connected to the blood inlet 122a of the blood purifier 120 described later on one end side. The arterial side line 111 is arranged with a blood pump 111a, an arterial side bubble detector 111b, an arterial side connection portion 111c, and a pair of transmitter / receiver 141A and 141B provided with an ultrasonic flow meter 140A described later.
The blood pump 111a discharges a liquid such as blood or a priming solution inside the arterial line 111 by squeezing the tube constituting the arterial line 111 with a roller.
The arterial side connection portion 111c is arranged on the other end side of the arterial side line 111. A needle that is punctured into the patient's blood vessel is connected to the arterial connection portion 111c.

The venous side line 112 is connected to the blood outlet 122b of the blood purifier 120 whose one end side is described later. The venous side line 112 is arranged with a drip chamber 112a, a venous side bubble detector 112b, a venous side clamp 112c, and a venous side connection portion 112d.
The drip chamber 112a stores a certain amount of blood in order to remove air bubbles, coagulated blood, and the like mixed in the vein side line 112.
The vein side bubble detector 112b is arranged on the downstream side of the drip chamber 112a and detects the presence or absence of bubbles in the tube.
The venous side clamp 112c is arranged on the downstream side of the venous side bubble detector 112b. The venous side clamp 112c is controlled according to the result of detecting bubbles by the venous side bubble detector 112b, and opens and closes the flow path of the venous side line 112.
The venous side connection portion 112d is arranged on the other end side of the venous side line. A needle that is punctured into the patient's blood vessel is connected to the venous side connection portion 112d.

The drug line 113 supplies the drug required during hemodialysis to the arterial line 111. One end of the drug line 113 is connected to the drug dispensing device 113a for delivering the drug, and the other end is connected to the arterial side line 111. Further, the drug line 113 is provided with a clamping means (not shown), and the flow path is closed by the clamping means except when the drug is injected.

The drainage line 114 is connected to the drip chamber 112a. A drainage line clamp 114a is arranged on the drainage line 114. The drainage line 114 is a line for draining the priming liquid in the priming step.

The blood purifier 120 includes a container body 121 formed in a cylindrical shape and a dialysis membrane (not shown) housed inside the container body 121. The inside of the container body 121 is divided into a blood flow path and a dialysate side flow path by a dialysate (neither is shown). The container body 121 is formed with a blood inlet 122a and a blood outlet 122b communicating with the blood circuit 110, and a dialysate inlet 123a and a dialysate outlet 123b communicating with the dialysate circuit 130. In this embodiment, a dialyzer is used as the blood purifier 120.

According to the above blood circuit 110 and blood purifier 120, the blood taken out from the artery of the subject (dialysis patient) flows through the arterial side line 111 by the blood pump 111a and flows through the blood side flow path of the blood purifier 120. Introduced in. The blood introduced into the blood purifier 120 is purified by the dialysate circulating in the dialysate circuit 130 described later via the dialysate membrane. The blood purified in the blood purifier 120 flows through the vein side line 112 and is returned to the subject's vein.

In the present embodiment, the dialysate circuit 130 is composed of a so-called closed capacity control type dialysate circuit 130. The dialysate circuit 130 includes a dialysate chamber 131, a dialysate supply line 132a, a dialysate introduction line 133a, a dialysate lead-out line 133b, a dialysate drainage line 132b, a bypass line L1, and water removal / removal. A back filtration pump P1 is provided.

The dialysate chamber 131 is composed of a rigid container capable of accommodating a constant volume (for example, 300 ml to 500 ml) of dialysate, and the inside of the container is provided with a soft diaphragm (diaphragm) to accommodate a liquid feed accommodating portion 1311a and drainage fluid. It is partitioned into a portion 1311b.

The dialysate supply line 132a is connected to the dialysate supply device (not shown) at the proximal end side and to the dialysate chamber 131 at the distal end side. The dialysate supply line 132a supplies the dialysate to the liquid feed accommodating portion 1311a of the dialysate chamber 131.

The dialysate introduction line 133a connects the dialysate chamber 131 and the dialysate introduction port 123a of the blood purifier 120, and dialysates the dialysate contained in the liquid feed accommodating portion 1311a of the dialysate chamber 131 to the blood purifier 120. Introduce into the liquid side flow path.

The dialysate lead-out line 133b connects the dialysate outlet 123b of the blood purifier 120 and the dialysate chamber 131, and leads the dialysate discharged from the blood purifier 120 to the drainage accommodating portion 1311b of the dialysate chamber 131. do.

The base end side of the dialysate drainage line 132b is connected to the dialysate chamber 131, and the dialysate drainage contained in the drainage storage portion 1311b is discharged.

The bypass line L1 connects the dialysate lead-out line 133b and the dialysate drainage line 132b.

The water removal / back filtration pump P1 is provided in the middle of the bypass line L1. The water removal / back filtration pump P1 is controlled by the control device 150 described later, and the dialysate inside the bypass line L1 is circulated to the dialysate drainage line 132b side (water removal direction) and the dialysate lead-out line 133b side. It is composed of a pump that is driven so that the liquid can be sent in the direction of circulation (reverse filtration direction).

According to the above dialysate circuit 130, the inside of the hard container constituting the dialysate chamber 131 is partitioned by a soft diaphragm (diaphragm), so that the amount of dialysate derived from the dialysate chamber 131 (drainage storage). The amount of dialysate supplied to section 1311a) and the amount of drainage collected in the dialysate chamber 131 (drainage accommodating section 1311b) can be made the same amount.
As a result, when the water removal / back filtration pump P1 is stopped, the flow rate of the dialysate introduced into the blood purifier 120 and the amount of the dialysate (drainage) drawn out from the blood purifier 120 are the same. Can be done.

Further, when the water removal / back filtration pump P1 is driven to send the liquid in the back filtration direction, a part of the drainage discharged from the dialysate chamber 131 passes through the bypass line L1 and the dialysate lead-out line 133b. It passes through and is collected again in the dialysate chamber 131. Therefore, the amount of dialysate derived from the blood purifier 120 is the amount collected in the dialysate chamber 131 (that is, the amount of dialysate flowing through the dialysate introduction line 133a), and the amount of dialysate flowing through the bypass line L1. The amount is obtained by subtracting the amount of liquid. As a result, the amount of dialysate taken out from the blood purifier 120 flows through the dialysate introduction line 133a by the amount of the dialysate (drainage) collected again in the dialysate chamber 131 through the bypass line L1. It will be less than the flow rate of the dialysate. That is, when the water removal / back filtration pump P1 is driven so as to send the liquid in the back filtration direction, a predetermined amount of dialysate is injected (back filtration) into the blood circuit 110 in the blood purifier 120.

On the other hand, when the water removal / back filtration pump P1 is driven to send the liquid in the water removal direction, the amount of the dialysate flowing through the dialysate lead-out line 133b is the dialysate collected in the dialysate chamber 131. (That is, the amount of dialysate flowing through the dialysate introduction line 133a) plus the amount of dialysate flowing through the bypass line L1. As a result, the amount of dialysate flowing through the dialysate lead-out line 133b is the same as the amount of dialysate (drainage) discharged to the dialysate drainage line 132b through the bypass line L1. It will be larger than the amount of dialysate in circulation. That is, when the water removal / back filtration pump P1 is driven so as to send the liquid in the water removal direction, a predetermined amount of water is removed from the blood in the blood purifier 120.

The ultrasonic flow meter 140A includes a pair of transmitter / receiver 141A and 141B and a flow rate measuring unit 142, both of which are connected by wiring. In the present embodiment, the pair of transmitter / receiver 141A and 141B are on the downstream side of the blood pump 111a and upstream of the blood purifier 120 in the arterial side line 111, and upstream of the connection point of the drug line 113. Attached to. By arranging it in such a place, it is possible to measure the flow rate in the blood circuit 110 without being affected by the influence of water removal by the blood purifier 120 or the injection of the drug solution from the drug line 113.

The transmitter / receiver 141A and 141B are composed of a piezoelectric element 1411 and a piezoelectric element cover 1412, respectively, and can transmit and receive ultrasonic signals. The ultrasonic wave front and back surface 1413 of the transmitter / receiver 141A and 141B is composed of a flat surface.

Here, the details of the arterial side line 111 (blood circuit 110) to which the pair of transmitter / receiver 141A and 141B are attached will be described with reference to FIGS. 2 and 3. FIG. 3 shows an XX sectional view of the measuring tube 110s in FIG. 2.

As described above, the arterial side line 111, the venous side line 112, the drug line 113, and the drainage line 114 constituting the blood circuit 110 are mainly composed of a tube. As the tubes constituting each of these lines, a main tube 110 m and a measurement tube 110s are used.

The main tube 110m is used for most of the tubes constituting the blood circuit 110 except for the measurement tube 110s. The main tube 110m is composed of a soft tube through which a liquid can flow and has flexibility. As the material of the main tube 110 m, for example, polyvinyl chloride is used.
In the present embodiment, a polyvinyl chloride tube having an outer diameter of 6.5 mm and an inner diameter of 4.7 mm is used as the main tube 110 m. Further, the surface of the main tube 110 m is generally subjected to a satin finish in order to prevent blocking in which the tubes stick to each other during the sterilization process at a high temperature.

As shown in FIGS. 2 and 3, the measuring tube 110s includes a pair of tube flat portions 1101 and is provided at a position in the blood circuit 110 where the ultrasonic flow meter 140A is attached. The measuring tube 110s is composed of a soft tube through which a liquid can flow and has flexibility, and which is more flexible than the main tube 110m. As the material of the measuring tube 110s, polyvinyl chloride or the like is used.
Since the measuring tube 110s is more flexible than the main tube 110m, it is possible to improve the adhesion of the transmitter / receiver 141A and 141B included in the ultrasonic flow meter 140A to the wavefront surface 1413.

As the material of the measuring tube 110s, it is preferable to use a material in which the propagation speed of ultrasonic waves is close to or faster than the propagation speed of blood. As a result, the refraction of ultrasonic waves at the boundary portion of the material can be reduced, so that the flow rate can be measured with high accuracy. As the measuring tube 110s, it is preferable to use a material having an ultrasonic propagation velocity of 1400 m / sec or more, and it is more preferable to use a material having an ultrasonic propagation velocity of 1500 m / sec or more.

The tube flat surface portion 1101 is a portion that comes into contact with the transmission / reception surface 1413 of the transmitter / receiver 141A and 141B (see FIG. 2), and is composed of a flat surface (see FIG. 3). As a result, the adhesion to the wave transmission / reception surface 1413 can be improved as compared with the main tube 110m whose outer wall is formed of a curved surface.
The distance between the outer walls of the pair of tube flat surfaces 1101 is set to, for example, 5 mm, and the distance between the inner walls is set to 3 mm. Further, the outer wall and the inner wall of the tube flat surface portion 1101 are formed so as to be substantially parallel to each other. As a result, the ultrasonic waves can be transmitted and received inside the measuring tube 110s while maintaining the directivity, and the ultrasonic waves can be efficiently propagated.
It is preferable that the surface of the measuring tube 110s is not subjected to a satin finish and is finished in a mirror surface. The surface roughness Ra of the measuring tube 110s is preferably 1.5 μm or less, and more preferably 1.0 μm. As a result, it is possible to prevent the formation of an air layer due to the presence of irregularities on the surface of the measuring tube 110s in a state where the flat surface portion 1101 and the wave front 1413 are in contact with each other. Therefore, it is possible to suppress the attenuation of the ultrasonic wave due to the air layer and reduce the measurement error of the propagation time, so that the flow rate can be measured with high accuracy.

As shown in FIG. 2, the pair of transmitter / receiver 141A and 141B are arranged at a predetermined distance in the flow direction of the liquid flowing through the blood circuit 110, and the transmission / reception surface 1413 is formed on the tube flat surface portion 1101 of the measuring tube 110s. It is attached in contact and diagonally facing each other. Further, the pair of transmitter / receiver 141A and 141B transmit / receive ultrasonic signals diagonally with respect to the flow direction of the liquid (blood).
Electrodes (not shown) are attached to both sides of the piezoelectric element 1411, and the input electric signal is converted into mechanical vibration, and the transmitted mechanical vibration is converted into electric signal and output. Can be done. The piezoelectric element 1411 is embedded and arranged inside a piezoelectric element cover 1412 formed of a resin such as rigid polyvinyl chloride, modified polyphenylene ether, polycarbonate, or acrylic. As the material of the piezoelectric element, piezoelectric ceramics such as lead zirconate titanate, a piezoelectric thin film such as zinc oxide, and a piezoelectric polymer film such as vinylidene fluoride can be applied. In this embodiment, lead zirconate titanate is used as the material of the piezoelectric element, and silver and platinum are used as the electrodes.

The flow rate measuring unit 142 includes a transmitting unit 1421, a receiving unit 1422, a transmission / reception switching unit 1423, and a flow rate calculation unit 1424, and is arranged in the control device 150 described later. The flow rate measuring unit 142 can measure the flow rate of the liquid based on the ultrasonic signals transmitted and received by the pair of wave transmitters and receivers 141A and 141B.

The transmission unit 1421 is connected to the piezoelectric element 1411 of the transmitter / receiver 141A or 141B via the transmission / reception switching unit 1423 to transmit an ultrasonic signal.
The receiving unit 1422 is connected to the piezoelectric element 1411 of the transmitter / receiver 10A or 10B via the transmission / reception switching unit 1423 to receive the ultrasonic signal and amplify the received ultrasonic signal.
The transmission / reception switching unit 1423 switches one of the transmitter / receiver 141A and 141B to the transmission unit 1421 and the other to the reception unit 1422. As a result, the transmission / reception switching unit 1423 transmits the ultrasonic signal from the transmitter / receiver 141A and receives it at the transmitter / receiver 141B, and the transmission / reception switching unit 141B transmits the ultrasonic signal from the transmitter / receiver 141B to transmit the ultrasonic signal to the transmitter / receiver 141A. It is possible to measure the propagation time when receiving with.
The flow rate calculation unit 1424 calculates the flow rate of the liquid flowing through the blood circuit 110 (measurement tube 110s) based on the propagation time of the ultrasonic signal between the transmitter / receiver 141A and 141B. The method of calculating the flow rate will be described in detail later.

The control device 150 is composed of an information processing device (computer), and includes a pump operating unit 151, a clamp operating unit 152, and a flow rate measuring unit 142.

The pump operation unit 151 controls the operation of various pumps arranged in the blood circuit 110 and the dialysate circuit 130.

The clamp operation unit 152 controls the operation of various clamps arranged in the blood circuit 110 and the dialysate circuit 130 according to the operation of various pumps and the detection result of bubbles by the bubble detector.

The control device 150 described above controls and operates the operation of the hemodialysis device 100A by executing the control program of each step described below.
Each step includes a priming step, which is a preparatory step for cleaning and purifying the blood circuit 110 and the blood purifier 120, a blood removal step in which the patient's blood is filled in the blood circuit 110 after puncture and circulated outside the body, and a blood removal step. Subsequently, a dialysis step of dialysis and purification of blood, a blood return step of returning the blood in the blood circuit 110 to the patient's body, and the like are performed.

In the present embodiment, the control device 150, the water removal / back filtration pump P1, the drug injection device 113a, the ultrasonic flow meter 140A and the blood pump 111a are integrated in a predetermined arrangement, and the console (device main body) 160 is integrated. It is composed.

Next, a specific method for calculating the flow rate in the flow rate calculation unit 1424 will be described. There are various methods for calculating the flow rate using ultrasonic waves, such as the Doppler method and the propagation time difference method. In this embodiment, the flow rate Q is calculated as follows using the propagation time reciprocal difference method as an example. do. The transmitter / receiver 141A and 141B transmit / receive ultrasonic signals diagonally with respect to the flow direction of the liquid. Specifically, they are arranged facing the outside of the measuring tube 110s so that the angle formed by the direction in which the ultrasonic signal is transmitted and received and the direction in which the liquid flows is a predetermined angle φ, and the ultrasonic signal is alternately transmitted and received. Then, the time required for the propagation of the ultrasonic signal is measured (see FIG. 2).

Time _{T AB} where ultrasonic waves from transducers 141A to 141B propagates, time _{T BA} ultrasound propagates from the transducer 141B to 141A, the distance of propagation of the ultrasonic L, sound velocity C, the measuring tube Let V be the flow velocity of the liquid in 110s.
In a state in which in the measuring tube 110s liquid filled, the actual flow rate is zero, i.e. when the flow velocity V is zero, equal to the T _AB and T _BA,
T _AB = T _BA = L / C ... (a)
Will be.

As shown in FIG. 2, when the liquid flows from the transmitter / receiver 141A side toward the transmitter / receiver 141B side at a flow velocity V,
T _AB = L / (C + Vcosθ) ... (b)
And
T _BA = L / (C-Vcosθ) ... (c)
Will be. These (b) and (c) expression each propagation time from the relationship of _{T AB,} taking the difference between the reciprocal of _{T BA,}
1 / T _AB- 1 / T _BA = (2Vcosθ) / L ... (d)
Will be. When the flow velocity V is obtained from the equation (d),
V = L / (2cosθ) × (1 / T _AB- 1 / T _BA ) ・ ・ ・ (e)
Will be. According to the equation (e), the flow velocity V can be calculated by measuring the propagation time of the ultrasonic wave.

According to the hemodialysis apparatus 100A provided with the blood circuit 110 and the ultrasonic flow meter 140A of the first embodiment described above, the following effects are obtained.

(1) The blood circuit 110 is configured to include a main tube 110m and a measuring tube 110s having a tube flat surface portion 1101 in contact with the wave front / reception surface 1413 and used for measuring the flow rate, and the measuring tube 110s. It is assumed that the transmitter / receiver 141A and 141B are attached. As a result, the adhesion between the tube flat surface portion 1101 of the measuring tube 110s and the transmitting / receiving wave surface 1413 of the transmitter / receiver 141A and 141B can be improved, so that ultrasonic waves can be efficiently propagated and the measurement accuracy of the flow rate can be improved. Can be raised.

(2) The measuring tube 110s was made of a soft resin having more flexibility than the main tube 110m. As a result, the adhesion of the measuring tube 110s to the wave front 1413 can be further improved, so that ultrasonic waves can be efficiently propagated and the measurement accuracy of the flow rate can be improved. Further, since the flexibility of only the measuring tube 110s portion is increased, the handling performance as the blood circuit 110 is not deteriorated.

(3) The measuring tube 110s was made of a material having an ultrasonic propagation velocity of 1400 m / sec or more. As a result, the time for the ultrasonic wave to propagate through the tube wall can be shortened and the measurement error of the propagation time can be reduced, so that the flow rate can be measured with high accuracy.

(4) The measurement tube 110s had a surface roughness of Ra 1.5 μm or less. As a result, it is possible to prevent the formation of an air layer due to the presence of irregularities on the surface of the measuring tube 110s in a state where the flat surface portion 1101 of the tube and the wave front / reception surface 1413 are in contact with each other. Therefore, it is possible to suppress the attenuation of the ultrasonic wave due to the air layer and reduce the measurement error of the propagation time, so that the flow rate can be measured with high accuracy.

(5) A pair of transmitter / receiver 141A and 141B are arranged at a predetermined distance in the blood flow direction in the blood circuit 110 (measurement tube 110s), and an ultrasonic signal is transmitted obliquely with respect to the blood flow direction. It was supposed to be sent and received. Thereby, the flow rate can be calculated by using the propagation time inverse difference method.

<Second Embodiment>
Next, the second embodiment will be described. The present embodiment is the same as the configuration of the first embodiment except that the configuration of the ultrasonic flow meter is different, so the same reference numerals are given and the description thereof will be omitted.

The configuration of the mounting portion of the ultrasonic flow meter 140B in the second embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 is an explanatory view of an attachment portion of the ultrasonic flow meter 140B in the blood circuit 110, and FIG. 5 shows a sectional view taken along the line YY in FIG.

In the second embodiment, as shown in FIG. 4, the ultrasonic flow meter 140B includes a pair of transmitter / receiver 141A and 141B, a flow rate measuring unit 142, and a circuit mounting unit 143, and the transmitter / receiver 141A. The 141B and the flow rate measuring unit 142 are connected by wiring (not shown). Also in the present embodiment, as in the first embodiment, the pair of transmitter / receiver 141A and 141B are on the downstream side of the blood pump 111a and upstream of the blood purifier 120 in the arterial side line 111, and are on the drug line. It is installed on the upstream side of the connection point of 113. By arranging it in such a place, it is possible to measure the flow rate in the blood circuit 110 without being affected by the influence of water removal by the blood purifier 120 or the injection of the drug solution from the drug line 113.

The circuit mounting portion 143 is configured in a block shape having a groove having a width in which the measuring tube 110s can be mounted. The pair of side surfaces constituting the groove of the circuit mounting portion 143 constitute a pair of sensor plane portions 1431A and 1431B arranged in parallel and opposed to each other.
The pair of sensor flat surface portions 1431A and 1431B are arranged so that the measuring tubes 110s are sandwiched by the tube flat surface portions 1101 so as to face each other. Further, as shown in FIG. 5, the transmitter / receiver 141A and 141B are fixedly arranged on the circuit mounting portion 143 so that the transmission / reception surface 1413 is flush with the sensor flat surface portions 1431A and 1431B, respectively.
The measuring tube 110s is mounted on the circuit mounting portion 143 so that the flat surface portion 1101 of the tube and the flat surface portions 1431A and 1431B of the sensor are in contact with each other.

According to the circuit mounting portion 143 described above, the tube flat surface portion 1101 and the sensor flat surface portions 1431A and 1431B are in close contact with each other only by mounting the measurement tube 110s constituting the blood circuit 110 on the circuit mounting portion 143. It is fixed with. Further, since the transmitter / receiver 141A and 141B are fixedly arranged on the circuit mounting portion 143, the distance between the transmitter / receiver 141A and 141B can be kept constant, and the measurement accuracy of the flow rate can be improved.

According to the hemodialysis apparatus provided with the blood circuit 110 and the ultrasonic flow meter 140B of the second embodiment described above, the following effects are obtained in addition to the above-mentioned effects (1) to (5).

(6) The ultrasonic flow meter 140B is attached to a circuit mounting portion 143 having a pair of sensor flat surface portions 1431A and 1431B arranged so as to sandwich and face the measuring tubes 110s, and to these pair of sensor flat surface portions 1431A and 1431B. It was configured to include a pair of transmitters and receivers to be arranged. As a result, the measuring tube 110s constituting the blood circuit 110 can be fixed in close contact with the tube flat surface portion 1101 and the sensor flat surface portions 1431A and 1431B only by attaching the measurement tube 110s to the circuit mounting portion 143. Further, since the transmitter / receiver 141A and 141B can be fixedly arranged on the circuit mounting portion 143, the distance between the transmitter / receiver 141A and 141B can be kept constant, and the measurement accuracy of the flow rate can be improved.

<Third Embodiment>
Next, the third embodiment will be described. The present embodiment is the same as the configuration of the second embodiment except that the configurations of the blood circuit and the ultrasonic flow meter are different, and thus the same reference numerals are given and the description thereof will be omitted.

The mounting partial configuration of the ultrasonic flow meter 140C in the third embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 is an explanatory view of an attachment portion of the ultrasonic flow meter 140C in the blood circuit 110C, and FIG. 7 shows a ZZ cross-sectional view in FIG.

The third embodiment differs from the first and second embodiments in that the blood circuit 110 does not have the measuring tubes 110s.
As shown in FIG. 6, the ultrasonic flow meter 140C includes a pair of transmitter / receiver 141A and 141B, a flow rate measuring unit 142, and a circuit mounting unit 143, and includes transmitter / receiver 141A, 141B and a flow rate measuring unit 142. Is connected by wiring (not shown). Also in the present embodiment, as in the first embodiment and the second embodiment, the pair of transmitter / receiver 141A and 141B are located on the downstream side of the blood pump 111a and upstream of the blood purifier 120 in the arterial side line 111. Therefore, it is attached to the upstream side of the connection point of the drug line 113. By arranging it in such a place, it is possible to measure the flow rate in the blood circuit 110 without being affected by the influence of water removal by the blood purifier 120 or the injection of the drug solution from the drug line 113.

The circuit mounting portion 143 is configured in a block shape having a groove having a width that can be mounted in a state where the main tube 110 m is deformed to some extent. The pair of side surfaces constituting the groove of the circuit mounting portion 143 constitute a pair of sensor plane portions 1431A and 1431B arranged in parallel and opposed to each other.
The pair of sensor flat surface portions 1431A and 1431B are arranged so as to be able to sandwich and face the main tube 110m. Further, as shown in FIG. 6, the transmitter / receiver 141A and 141B are fixedly arranged on the circuit mounting portion 143 so that the transmission / reception surface 1413 is flush with the sensor plane portions 1431A and 1431B, respectively.

As shown in FIG. 7, the pair of sensor flat surface portions 1431A and 1431B has a distance between the sensor flat surface portions 1431A and 1431B, which is a pair of the main tube 110m in a state where the main tube 110m is mounted on the circuit mounting portion 143. It is arranged in the circuit mounting portion 143 so that the outer wall and the inner wall of the tube wall are substantially parallel to the entire portion in contact with the sensor flat surface portions 1431A and 1431B.

According to the circuit mounting portion 143 described above, the main tube 110m and the sensor flat surface portions 1431A and 1431B are in close contact with each other only by mounting the main tube 110m mainly constituting the blood circuit 110 on the circuit mounting portion 143. It is fixed. Further, since the transmitter / receiver 141A and 141B are fixedly arranged on the circuit mounting portion 143, the distance between the transmitter / receiver 141A and 141B can be kept constant, and the measurement accuracy of the flow rate can be improved. Further, it is also possible to apply the measurement tubes 110s described in the first embodiment and the second embodiment as the tubes mounted on the circuit mounting portion 143.

According to the hemodialysis apparatus provided with the blood circuit 110C and the ultrasonic flow meter 140C of the third embodiment described above, the following effects are obtained.

(7) The ultrasonic flow meter 140C is arranged in a circuit mounting portion 143 having a pair of sensor flat surface portions 1431A and 1431B arranged so as to sandwich and face the main tube 110 m, and in the pair of sensor flat surface portions 1431A and 1431B. The distance between the pair of sensor plane portions 1431A and 1431B is set to include a pair of transmitter / receivers, and a pair of main tubes 110m in a state where the main tube 110m is mounted on the circuit mounting portion 143. The length is set so that the outer wall and the inner wall of the tube wall are substantially parallel to each other in the entire portion in contact with the sensor flat surface portions 1431A and 1431B. As a result, even if the tube constituting the measurement point of the blood circuit is not the measurement tube 110s but the main tube 110 m, the pair of sensor flat surface portions 1431A and 1431B can be set to appropriate sizes to set the main tube 110 m. And the wave front surface 1413 can be improved, and the measurement accuracy of the flow rate can be improved.

<Modification example>
Next, a modified example of the third embodiment will be described with reference to FIG.
The present embodiment is the same as the configuration of the third embodiment except that the configuration of the ultrasonic flow meter is different, and thus the description thereof will be omitted. Of the ultrasonic flowmeter 140D, the configuration of the circuit mounting portion 143 will be described in detail with reference to FIG. 8.

The modified ultrasonic flow meter 140D includes a pair of transmitter / receiver 141A and 141B, a flow measuring unit 142, a circuit mounting unit 143, a base portion 1432, and a lid portion 1433 that can be opened and closed. , The transmitter / receiver 141A, 141B and the flow rate measuring unit 142 are connected by wiring.

The circuit mounting portion 143 includes a pair of sensor flat surface portions 1431A and 1431B.
The base portion 1432 and the lid portion 1433 are arranged so that the main tube 110m can be sandwiched and opposed to each other in a direction substantially orthogonal to the direction in which the pair of sensor flat surface portions 1431A and 1431B face each other, and the main tube 110m can be mounted. , Fixed to the device body 160 and arranged.
The pair of sensor flat surface portions 1431A and 1431B are arranged so as to be able to sandwich and face the main tube 110m. Further, the transmitter / receiver 141A and 141B are fixed to the circuit mounting portion 143 so that the transmission / reception surface 1413 is flush with the sensor plane portions 1431A and 1431B and at the vertical center portion of the sensor plane portions 1431A and 1431B, respectively. And are placed.

As shown in FIG. 8, the pair of sensor flat surface portions 1431A and 1431B has a distance between the sensor flat surface portions 1431A and 1431B, which is a pair of the main tube 110m in a state where the main tube 110m is mounted on the circuit mounting portion 143. It is arranged in the circuit mounting portion 143 so that the outer wall and the inner wall of the tube wall are substantially parallel to the entire portion in contact with the sensor flat surface portions 1431A and 1431B.

According to the circuit mounting portion 143 of the modified example described above, the main tube 110m is simply mounted on the circuit mounting portion 143 and the lid portion 1433 is closed by simply mounting the main tube 110m that mainly constitutes the blood circuit 110C. Is pushed in the vertical direction by the base portion 1432 and the lid portion 1433, so that the main tube 110 m and the sensor flat surface portions 1431A and 1431B can be fixed in close contact with each other. Further, by arranging the transmitter / receiver 141A and 141B in the central portion in the vertical direction of the sensor flat surface portions 1431A and 1431B, ultrasonic waves are applied only to the portion where the sensor flat surface portions 1431A and 1431B and the wave transmission / reception surface 1413 are in close contact with each other. , Ultrasonic waves can be propagated efficiently. Further, since the transmitter / receiver 141A and 141B are fixedly arranged on the circuit mounting portion 143, the distance between the transmitter / receiver 141A and 141B can be kept constant, and the measurement accuracy of the flow rate can be improved. Further, it is also possible to apply the measurement tubes 110s described in the first embodiment and the second embodiment as the tubes mounted on the circuit mounting portion 143.

Although the preferred embodiments and modifications of the blood circuit of the present invention, the ultrasonic flow meter, and the hemodialysis apparatus including these are described above, the present invention is limited to the above-mentioned embodiments and modifications. However, it can be changed as appropriate.
For example, in each embodiment and modification, an example in which a pair of ultrasonic wave transmitters and receivers are arranged facing each other is shown, but the present invention is not limited to this. Only one transmitter / receiver may be arranged, or two transmitters / receivers may be arranged on the same side to transmit / receive reflected ultrasonic waves.

Further, in each embodiment and the modified example, an example of the propagation time reciprocal difference method is shown as a method of calculating the flow rate, but the present invention is not limited to this. The flow rate may be calculated by a well-known calculation method such as the Doppler method or the propagation time difference method.

100A Blood dialysis machine 110 Blood circuit 110m Main tube 110s Measuring tube 1101 Tube flat surface 111 Arterial side line 111a Blood pump 112 Intravenous side line 113 Drug line 114 Drainage line 120 Blood purifier 130 Dialysis fluid circuit P1 Water removal / back filtration Pump 140A, 140B, 140C, 140D Ultrasonic flow meter 141A, 141B Transmitter / receiver 1413 Transmission / reception surface 142 Flow measurement unit 1421 Transmission unit 1422 Receiver unit 1423 Transmission / reception switching unit 1424 Flow calculation unit 143 Circuit mounting unit 1431A, 1431B Sensor flat unit 1432 Base 1433 Lid 150 Control device 151 Pump operating unit 152 Clamp operating unit

Claims (5)

Extracorporeal with a blood pump for flowing blood and an ultrasonic flow meter for transmitting and receiving ultrasonic waves, the transmission and reception surface of the transmitter and receiver being configured with a flat surface, and an ultrasonic flow meter for measuring the flow rate of blood. A blood circuit used in a circulation device, connected to a blood purifier, and equipped with the blood pump to circulate blood.
With the main tube
A measuring tube having a flat surface portion of the tube in contact with the wavefront, used for measuring the flow rate, and made of a soft resin having more flexibility than the main tube.
A blood circuit in which the transmitter / receiver is attached to the measuring tube. The ultrasonic flow meter is
A circuit mounting portion having a pair of sensor plane portions arranged so as to be able to sandwich the measuring tube, and a circuit mounting portion.
The blood circuit according to claim 1, further comprising the pair of transmitter / receivers arranged on the pair of sensor planes. The blood circuit according to claim 1 or 2, wherein the measurement tube is made of a material having an ultrasonic propagation velocity of 1500 m / sec or more. The blood circuit according to any one of claims 1 to 3, wherein the measuring tube has a surface roughness of Ra 1.5 μm or less. A blood purifier that purifies blood,
A blood pump that flows blood,
The blood circuit according to any one of claims 1 to 4 and
Equipped with an ultrasonic flow meter for measuring blood flow,
The ultrasonic flow meter is
A circuit mounting portion having a pair of sensor plane portions arranged so as to be able to sandwich and face the tubes constituting the blood circuit, and a circuit mounting portion.
A pair of transmitter / receivers arranged on the pair of sensor planes to transmit / receive ultrasonic waves are provided.
The distance between the pair of sensor flat surfaces is such that the outer wall and the inner wall of the tube wall are substantially parallel to the entire portion of the tube that contacts the pair of sensor flat portions when the tube is mounted on the circuit mounting portion. Is the length that becomes
The circuit mounting portion further includes a base portion and a lid portion that can be opened and closed.
An extracorporeal circulation device in which the base portion and the lid portion are arranged so as to be able to sandwich the tube in a direction substantially orthogonal to the direction in which the pair of sensor plane portions face each other.

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