WO2023070275A1

WO2023070275A1 - Air trap device for hemodialysis, corresponding set for hemodialysis and corresponding methods for operating air trap device

Info

Publication number: WO2023070275A1
Application number: PCT/CN2021/126168
Authority: WO
Inventors: Heqing Huang; Dacey John RYAN; Hao Li; Huabiao YANG; Manfred Weis; Martin Urban
Original assignee: Fresenius Medical Care Deutschland Gmbh; Fresenius Medical Care R&D (Shanghai) Co., Ltd.
Priority date: 2021-10-25
Filing date: 2021-10-25
Publication date: 2023-05-04

Abstract

An air trap device (1, 2, 3, 4) for hemodialysis comprises: an inlet (11, 21, 31, 41); an outlet (12, 22, 32, 42); and a reservoir (13, 23), with which the inlet (11, 21, 31, 41) and the outlet (12, 22, 32, 42) are fluidly communicated; wherein both the inlet (11, 21, 31, 41) and the outlet (12, 22, 32, 42) are disposed at a lower end of the reservoir (13, 23) relative to a vertical direction in use; and wherein the reservoir (13, 23) is configured to define a cavity (133) comprising at least two chambers in which adjacent chambers can be fluidly communicated. A set for hemodialysis comprising such an air trap device (1, 2, 3, 4) and corresponding methods for operating such an air trap device (1, 2, 3, 4). According to some embodiments of the present disclosure, the air can be trapped more efficiently and reliably and mixing of the blood and the priming liquid can be reduced greatly.

Description

Air Trap Device for Hemodialysis, Corresponding Set for Hemodialysis and Corresponding Methods for Operating Air Trap Device

Technical Field

The present disclosure relates to an air trap device for hemodialysis, a corresponding set for hemodialysis comprising such an air trap device and corresponding methods for operating such an air trap device.

Background Art

A dialysis treatment is a procedure for removing toxic substances and metabolites normally removed by the kidneys, and for aiding in regulation of fluid and electrolyte balance.

The dialysis treatment may be carried out by various types of dialysis procedures, such as a hemodialysis (HD) and a peritoneal dialysis (PD) .

For the hemodialysis, extracorporeal circuits are often used which comprise a filtering membrane for cleaning blood (for example, a dialyzer) , a tubing circuit for transporting the blood from and back to patients and a means for accessing the patient’s vascular system (for example, a fistula needle or catheter) .

To protect the patients from infusion of air, an air trap device is usually positioned on a venous return line of the tubing circuit.

Before the dialysis treatment, the air trap device should be filled. Usually, a venting line/port is disposed on a top of a chamber of the air trap device, which is connected to a HD machine, to vent the air in the chamber.

During the dialysis treatment, usually there’s an air-blood interface in the chamber, which can promote foaming or coagulation of the blood, and decrease the air trap/separation performance.

Also, during the dialysis treatment, some HD machines can monitor a level in the chamber, and allow operators to manually adjust the level for example via a syringe, or to vent the air via the venting line.

The know air trap device has some disadvantages, such as a lower air trap efficiency, complicated operations, uncontrollable mixing of the blood with saline and so on.

Therefore, there is a need to further improve the known air trap device.

Summary of the Disclosure

In view of the problems existing in the prior art, an object of the disclosure is to provide an improved air trap device for hemodialysis, a corresponding set for hemodialysis comprising such an air trap device and corresponding methods for operating such an air trap device.

For achieving this object, according to a first aspect, provided is an air trap device for hemodialysis, comprising: an inlet; an outlet; and a reservoir, with which the inlet and the outlet are fluidly communicated; wherein both the inlet and the outlet are disposed at a lower end of the reservoir relative to a vertical direction in use; and wherein the reservoir is configured to define a cavity comprising at least two chambers in which adjacent chambers can be fluidly communicated.

According to an optional embodiment of the present disclosure, the reservoir is configured to separate blood from other liquid different from the blood in a controllable manner during a treatment phase of the hemodialysis; and/or the at least two chambers are configured to form at least two flow channels which each lead to the outlet or are configured to control fluid flow characteristics between the adjacent chambers; and/or the inlet is disposed at a bottom edge of the reservoir so that the inlet is oriented downwards; and/or the outlet is disposed at a lateral edge of the reservoir so that the outlet is oriented laterally; and/or the air trap device is configured to be disposed at a venous port of a dialyzer.

According to an optional embodiment of the present disclosure, the air trap device is configured to be incorporated, preferably integrated, into a venous cap of the dialyzer; and/or the inlet is disposed at a corner of the reservoir.

According to an optional embodiment of the present disclosure, the at least two chambers comprise at least two first chambers arranged laterally side by side and each fluidly communicated between the inlet and the outlet.

According to an optional embodiment of the present disclosure, the at least two chambers comprise at least two second chambers arranged one above of another.

According to an optional embodiment of the present disclosure, the air trap device comprises a first pressure sensor for detecting a pressure within the cavity and/or a first level detector for detecting a liquid level within the cavity; and/or the at least two first chambers comprise a main channel chamber and a bypass channel chamber divided by a dividing wall; and/or the reservoir comprises a dam so that fluid entering via the inlet must flow over a top of the dam before further flowing downstream; and/or upper ends of the at least two first chambers can be fluidly communicated with each other through an upper flow path, and lower ends of the at least two first chambers can be fluidly communicated with each other through a lower flow path.

According to an optional embodiment of the present disclosure, the upper flow path is configured to be closable; and/or the lower flow path is configured to be closable; and/or the dam is configured to define an inlet channel, and the main channel chamber is disposed between the inlet channel and the bypass channel chamber; and/or the main channel chamber has a larger flow cross section than the bypass channel chamber.

According to an optional embodiment of the present disclosure, the at least two second chambers comprise a primary chamber and a secondary chamber disposed above the primary chamber and fluidly communicated with the primary chamber via a first fluid channel, wherein both the inlet and the outlet are fluidly communicated with the primary chamber.

According to an optional embodiment of the present disclosure, the first fluid channel is configured to be closable; and/or the first fluid channel is configured to only allow air to enter the secondary chamber from the primary chamber via the first fluid channel; or the first fluid channel is configured to allow liquid to enter the secondary chamber from the primary chamber via the first fluid channel; and/or the primary chamber is configured to be larger than the secondary chamber, particularly in a cross-section; and/or the reservoir comprises a first venting port for releasing a pressure in the secondary chamber; and/or the air trap device comprises a second pressure sensor for detecting a pressure within the primary chamber and/or the secondary chamber, and/or a second level detector for detecting a liquid level within the primary chamber and/or the secondary chamber; and/or the secondary chamber is offset relative to the primary chamber.

According to an optional embodiment of the present disclosure, the at least two second chambers further comprise an additional chamber disposed above the secondary chamber and fluidly communicated with the secondary chamber via a second fluid channel, wherein the second fluid channel is configured to only allow air to enter the additional chamber from the secondary chamber via the second fluid channel, and the first fluid channel is configured to allow liquid to enter the secondary chamber from the primary chamber via the first fluid channel.

According to an optional embodiment of the present disclosure, the reservoir comprises a second venting port for releasing a pressure in the additional chamber.

According to an optional embodiment of the present disclosure, the upper flow path is configured to be able to be closed by a first valve and/or a first motion; and/or the lower flow path is configured to be able to be closed by a second valve and/or a second motion; and/or the first fluid channel is configured to be able to be closed by a third valve and/or a third motion; or the first fluid channel is configured to be able to keep the entering liquid within the secondary chamber without need of closing of the first fluid channel; and/or the second fluid channel is configured to be able to be closed by a fourth valve and/or a fourth motion; and/or the first venting port and/or the second venting port is configured to only allow air to release.

According to an optional embodiment of the present disclosure, at least one of the first motion, the second motion, the third motion and the fourth motion is implemented actively by a driver and/or passively implemented by deformation of a material of a respective portion of the reservoir; and/or the first fluid channel comprises at least one first hole sized to keep the entering liquid within the secondary chamber without need of closing of the first hole; and/or the first venting port and/or the second venting port comprises a fifth valve or at least one second hole; and/or the first venting port and/or the second venting port is configured as a porous membrane.

According to an optional embodiment of the present disclosure, the driver comprises a plunger, preferably driven by a step motor and/or a pneumatic source; and/or at least one of the first valve, the second valve, the third valve and the fourth valve is a phantom valve; and/or the material comprises wax and/or shape memory alloy, and the deformation is caused by a temperature change of the material; and/or the fifth valve is a relief valve, or the at least one second hole comprises a plurality of micro holes, for example having a diameter of less than 5 microns, preferably generated by a laser.

According to a second aspect, provided is a set for hemodialysis, comprising: an extracorporeal circuit, comprising a dialyzer and a tubing circuit for transferring blood from and back to a patient; and the air trap device described above, which is disposed at a venous return line of the tubing circuit or at a venous port of the dialyzer.

According to a third aspect, provided is a method for operating the air trap device described above, comprising: a priming phase, in which a priming liquid is filled into the air trap device via the inlet without or with closing of the lower flow path, to flush out all air out of the outlet; and/or a treatment phase, in which blood flows into the air trap device via the inlet and flows out of the air trap device via the outlet with opening of the lower flow path and without or with closing of the upper flow path.

According to an optional embodiment of the present disclosure, if the lower flow path is opened during the priming phase, the priming liquid, preferably saline is filled at a first flowrate, for example of more than 800 ml/min, higher than a second flowrate of the blood flowing into the air trap device during the treatment phase; and/or if the upper flow path is opened during the treatment phase, the blood flows into the air trap device at a third flowrate than the first flowrate, for example of less than 500 ml/min.

According to a fourth aspect, provided is a method for operating the air trap device described above, comprising: a priming phase, in which the outlet is closed, a priming liquid is filled into the air trap device via the inlet to generate a first pressure within the primary chamber so as to compress all air into the secondary chamber via the first fluid channel and the first fluid channel is closed after priming, or in which the outlet is opened, the primary chamber is filled fully with the priming liquid via the inlet and the secondary chamber is filled at least partially with the priming liquid from the primary chamber via the first fluid channel; and/or a treatment phase, in which blood flows into the air trap device via the inlet while the air within the secondary chamber is not allowed to flow back into the primary chamber via the first fluid channel.

According to an optional embodiment of the present disclosure, during the treatment phase, the first fluid channel is covered by the priming liquid within the secondary chamber to prevent the air within the secondary chamber from flowing back into the primary chamber; and/or during the priming phase, the first pressure is determined by calculating at least based on a volume of the priming liquid, for example saline, filled into the primary chamber and/or monitored by a pressure sensor; and/or during the treatment phase and/or the priming phase, the air within the secondary chamber is released at least partially out of the air trap device; or during the treatment phase, the outlet is closed and a second pressure is generated in the reservoir to compress the air within the primary chamber into the secondary chamber via the first fluid channel and then the second pressure is reduced so as to push at least a part of the priming liquid within the secondary chamber back into the primary chamber via the first fluid channel to increase an air-blood level in the primary chamber.

According to an optional embodiment of the present disclosure, during the priming phase and/or the treatment phase, the secondary chamber is fully filled with the priming liquid.

According to some embodiments of the present disclosure, the air can be trapped more efficiently and reliably and mixing of the blood and the priming liquid can be reduced greatly.

Brief Description of the Drawings

The disclosure and advantages thereof will be further understood by reading the following detailed description of some preferred exemplary embodiments with reference to the drawings in which:

Fig. 1 schematically shows an air trap device according to a first exemplary implementation of the present disclosure in a sectional view.

Fig. 2 schematically shows how the air trap device works during a priming phase in which a priming liquid has filled fully a cavity of the air trap device.

Fig. 3 schematically shows how the air trap device works during a treatment phase in which some air has been trapped in a top area of a reservoir of the air trap device.

Fig. 4 schematically shows an air trap device according to a second exemplary implementation of the present disclosure in a sectional view.

Fig. 5 schematically shows how the air trap device works during a priming phase in which the priming liquid has filled fully a primary chamber of the air trap device.

Fig. 6 schematically shows how the air trap device works during a treatment phase in which some air has been trapped in a top area of the primary chamber.

Fig. 7 schematically shows an air trap device according to a third exemplary implementation of the present disclosure in a sectional view and also shows how the air trap device works during a priming phase.

Fig. 8 schematically shows how the air trap device works during a treatment phase in which some air released from the blood has been trapped in a top area of a primary chamber of the air trap device and the priming liquid entering a secondary chamber of the air trap device during a priming phase is kept within the secondary chamber.

Fig. 9 schematically shows how the air trap device works during the treatment phase in which an air-blood level is increased.

Fig. 10 schematically shows an air trap device according to a fourth exemplary implementation of the present disclosure in a sectional view.

Detailed Description of Preferred Embodiments

Some exemplary embodiments of the present disclosure will be described hereinafter in more details with reference to the drawings to better understand the basic concept of the present disclosure.

According to the disclosure, herein firstly proposed is an air trap device for hemodialysis, comprising: an inlet; an outlet; and a reservoir, with which the inlet and the outlet are fluidly communicated; wherein both the inlet and the outlet are disposed at a lower end of the reservoir relative to a vertical direction in use; and wherein the reservoir is configured to define a cavity comprising at least two chambers in which adjacent chambers can be fluidly communicated.

Fig. 1 schematically shows the air trap device according to a first exemplary implementation of the present disclosure in a sectional view.

It may be understood by the skilled person in the art that this sectional view is not limited to a specific section, and instead is to only illustrate the basic concept of the air trap device according to the present disclosure. That is to say, the air trap device may be implemented in various structural designs within the scope of spirt or teaching of the disclosure.

As shown in Fig. 1, the air trap device 1 may comprise: an inlet 11 for receiving a fluid, such as blood, priming liquid and any other applicable fluids; an outlet 12 for discharging the fluid from an interior space of the air trap device 1; and a reservoir 13, with which the inlet 11 and the outlet 12 are fluidly communicated. In an exemplary application, the air trap device 1 should be oriented substantially as shown in Fig. 1. Thus, it may be understood by the skilled person in the art that as shown in Fig. 1, both the inlet 11 and the outlet 12 are disposed at a lower end of the reservoir 13 relative to the vertical direction in such an application.

According to an exemplary embodiment of the present disclosure, the inlet 11 may be disposed at a bottom edge 131 of the reservoir 13 so that the inlet 11 may be oriented to introduce the fluid to enter the air trap device 1 upwards.

According to an exemplary embodiment of the present disclosure, the outlet 12 may be disposed at a lateral edge 132 of the reservoir 13 so that the outlet 12 may be oriented to guide the fluid to discharge from the air trap device 1 laterally (for example, in Fig. 1, leftwards) .

As shown in Fig. 1, the inlet 11 may be disposed adjacent to another lateral edge, preferably opposite to the lateral edge 132, so that a distance between the inlet 11 and the outlet 12 may prolong a flow path of the blood flowing from the inlet 11 to the outlet 12 and keep the blood staying in the reservoir 13 for a longer time period, which will allow air contained in the blood to be fully released from the blood. As an example, the inlet 11 may be disposed at a corner of the reservoir 13 (for example, in Fig. 1, the lower right corner) , at which the lateral wall and a bottom wall of the reservoir 13 intersect with each other.

It may be understood by the skilled person in the art that arrangement of the inlet 11 and the outlet 12 is not limited hereto.

As can be seen from Fig. 1, the reservoir 13 may be configured to define a cavity 133 comprising at least two chambers, herein being shown only in two chambers, which are marked by

reference signs

1331 and 1332 respectively and which are adjacent to each other and can be fluidly communicated with each other.

According to an exemplary embodiment of the present disclosure, as shown in Fig. 1, the at least two chambers may be configured to form at least two flow channels which each lead to the outlet 12 (in Fig. 1, for example, only two flow channels are formed as shown in arrows) . In this case, the two chambers each act as a respective channel so that the fluid entering the cavity 133 via the inlet 11 flow through them before reaching the outlet 12.

According to an exemplary embodiment of the present disclosure, the air trap device 1 may be configured to be disposed at a venous port of a dialyzer (not shown) . The treated blood will flow back to a patient through the air trap device 1, in which the air contained in the blood is trapped.

Particularly, the air trap device 1 may be configured to be incorporated, preferably integrated, into a venous cap of the dialyzer, which will simplify the corresponding configuration and use.

According to an exemplary embodiment of the present disclosure, as shown in Fig. 1, the at least two chambers may comprise at least two chambers arranged laterally side by side and each fluidly communicated between the inlet 11 and the outlet 12. As described above, in the exemplary embodiment as shown in Fig. 1, only two chambers are provided laterally side by side.

According to an exemplary embodiment of the present disclosure, the two chambers may be embodied as a main channel chamber 1331 and a bypass channel chamber 1332 divided by a dividing wall 1333 respectively.

According to an exemplary embodiment of the present disclosure, as shown in Fig. 1, upper ends of the main channel chamber 1331 and the bypass channel chamber 1332 can be fluidly communicated with each other through an upper flow path 1334, and lower ends of the main channel chamber 1331 and the bypass channel chamber 1332 may be fluidly communicated with each other through a lower flow path 1335.

According to an exemplary embodiment of the present disclosure, as shown in Fig. 1, the reservoir 13 may comprise a dam 134 so that the fluid entering via the inlet 11 must flow over a top 1341 of the dam 134 before further flowing downstream. Specifically, the fluid first flows upwards and then over the top 1341 of the dam 134 before entering the main channel chamber 1331. Thus, when the blood enters via the inlet 11, it will be forced to flow upwards to prevent direct flowing from the inlet 11 to the outlet 12, which will allow the air contained in the blood to be fully released from the blood.

As an exemplary embodiment of the present disclosure, the dividing wall 1333 may be formed integrally with the respective walls of the reservoir 13. Similarly, the dam 134 also may be formed integrally with the respective walls of the reservoir 13. It may be understood by the skilled person in the art that the inlet 11 and the outlet 12 also may be formed integrally with the reservoir 1. In this case, the reservoir 13, the inlet 11 and the outlet 12 may be formed integrally by a single injection molding process. In this case, they may be made of the same material.

Further, the dividing wall 1333 and the dam 134 are only schematically shown here in linear a shape and thus they are not limited hereto. Moreover, it may be understood by the skilled person in the art that Fig. 1 is only a schematic sectional view and thus the dividing wall 1333 and the dam 134 may be in any suitable shapes, for example a curved shape, particularly according to a shape of the reservoir 13.

According to an exemplary embodiment of the present disclosure, as shown in Fig. 1, the main channel chamber 1331 may have a larger flow cross section than the bypass channel chamber 1332.

As can be seen from Fig. 1, the dam 134 may be configured to define an inlet channel 1342, and the main channel chamber 1331 may be disposed between the inlet channel 1342 and the bypass channel chamber 1332. Specifically, the inlet channel 1342 may be formed between the dam 134 and the corresponding wall of the reservoir 13, as shown in Fig. 1.

According to an exemplary embodiment of the present disclosure, the air trap device 1 may further comprise a pressure sensor (not shown) for detecting a pressure within the cavity 133 of the reservoir 13 and/or a level detector (not shown) for detecting a liquid level within the cavity 133 of the reservoir 13. It may be understood by the skilled person in the art that provision of the pressure sensor and the level detector can provide a possibility of controlling or monitoring of use or operation of the air trap device 1.

According to an exemplary embodiment of the present disclosure, the upper flow path 1334 may be configured to be closable.

Preferably, the upper flow path 1334 may be configured to be able to be closed by a valve (not shown) and/or a motion.

Further, according to an exemplary embodiment of the present disclosure, the motion may be implemented actively by a driver (not shown) and/or passively implemented by deformation of a material of a respective portion (for example a portion adjacent to the upper flow path 1334) of the reservoir 13. As an example, the driver may comprise a plunger, preferably driven by a step motor (not shown) and/or a pneumatic source (not shown) .

According to an exemplary embodiment of the present disclosure, the valve may be a phantom valve.

According to an exemplary embodiment of the present disclosure, the material may comprise wax and/or shape memory alloy, and the deformation may be caused by a temperature change of the material, for example due to different temperatures of the fluid.

Similarly, the lower flow path 1335 also may be configured to be closable. The lower flow path 1335 may be closed in a similar manner to the upper flow path 1334 and thus a further description is omitted here for brevity.

Time and function of opening and closing the upper flow path 1334 and/or the lower flow path 1335 will be further described below in connection with a method for operating the air trap device 1 as shown in Fig. 1.

Use or operation of the air trap device 1 mainly involves two phases: a priming phase and a treatment phase executed after the priming phase.

Fig. 2 schematically shows how the air trap device 1 works during the priming phase in which a priming liquid has filled fully the cavity 133.

Fig. 3 schematically shows how the air trap device 1 works during the treatment phase in which some air has been trapped in a top area of the reservoir 13.

According to an exemplary embodiment of the present disclosure, during the priming phase, the priming liquid, for example saline may be filled into the air trap device 1 via the inlet 11 without or with closing of the lower flow path 1335, to flush out all air out of the outlet 12 via the bypass channel chamber 1332.

To flush the air out of the outlet 12, the priming fluid with a higher flowrate may be used to flush out all the air via the bypass channel chamber 1332 without closing of the lower flow path 1335, because such a higher flowrate can flush all the air out of the outlet 12 rapidly, almost without a possibility of the air being captured in the cavity 133.

The reservoir 13, particularly the main channel chamber 1331 and the bypass channel chamber 1332 may be designed specially to allow all the air to be flushed out at the higher flowrate, but not allow all the air to be flushed out at a lower flowrate.

It’s recommended that the relatively higher flowrate may be higher than a flowrate of the blood flowing into the air trap device 1 during the treatment phase. For example, the higher flowrate may be more than 800 ml/min to provide sufficient fluid/pressure to rapidly flush out all the air via the outlet 12.

Alternatively, if the lower flow path 1335 is closed during the priming phase (in Fig. 2, the lower flow path 1335 is closed schematically with a black block 14) , a lower flowrate, for example of less than 500 ml/min may be sufficient to flush out all the air via the bypass channel chamber 1332.

Thus, it may be advantageous if the lower flow path 1335 is configured to be closable, as described above.

During the treatment phase, the blood flows into the air trap device 1 via the inlet 11 and flows out of the air trap device 1 via the outlet 12 without or with closing of the upper flow path 1334. The air released from the blood can be trapped in a top area of the reservoir 13.

During the treatment phase, the lower flow path 1335 may need to be opened to prevent the blood from staying in the main channel chamber 1331.

If the upper flow path 1334 is opened during the treatment phase, the blood may flow into the air trap device 1 at a lower flowrate. For achieving this, the reservoir 13, particularly the main channel chamber 1331 and the bypass channel chamber 1332 may be designed specially to allow for trapping/separating the air from the blood flowing at the lower flowrate, for example of less than 500 ml/min.

Alternatively, the upper flow path 1334 also may be closed (in Fig. 3, the upper flow path 1334 is closed schematically with a black block 15) and in this case, the air can be trapped reliably.

Thus, it may be seen from the above that the reservoir 13 may be configured to separate the blood from other liquid (for example the priming liquid) different from the blood in a controllable manner during the treatment phase of the hemodialysis, because the priming liquid can be discharged completely from the reservoir 13 in a controllable manner during the priming phase and thus there is no other liquid in the cavity 133 except for the blood during the treatment phase.

Fig. 4 schematically shows the air trap device 2 according to a second exemplary implementation of the present disclosure in a sectional view. In order to avoid unnecessary repetitive description, a focus will be placed mainly on some differences from the first exemplary implementation of the present disclosure as shown in Fig. 1 to Fig. 3. Thus, some features described in connection with Fig. 1, Fig. 2 and Fig. 3 also may be used in the air trap device 2 without technical conflicts, although they may not be clearly stated below.

According to the second exemplary implementation, the at least two chambers may comprise at least two chambers arranged one above of another. In Fig. 4, only two chambers are provided as an illustrative example.

Specifically, as shown in Fig. 4, according to an exemplary embodiment of the present disclosure, the at least two chambers may comprise a primary chamber 2331 and a secondary chamber 2332 disposed above the primary chamber 2331 and fluidly communicated with the primary chamber 2331 via a fluid channel 2333, wherein both an inlet 21 and an outlet 22 are fluidly communicated with the primary chamber 2331.

According to an exemplary embodiment of the present disclosure, the fluid channel 2333 may be configured to be closable.

According to an exemplary embodiment of the present disclosure, the fluid channel 2333 may be configured to only allow the air to enter the secondary chamber 2332 from the primary chamber 2331 via the fluid channel 2333.

As shown in Fig. 4, according to an exemplary embodiment of the present disclosure, the primary chamber 2331 may be configured to be larger than the secondary chamber 2332, particularly in a cross-section.

Fig. 5 schematically shows how the air trap device 2 works during a priming phase in which the priming liquid has filled fully the primary chamber 2331.

Fig. 6 schematically shows how the air trap device 2 works during a treatment phase in which some air has been trapped in a top area of the primary chamber 2331.

According to an exemplary embodiment of the present disclosure, as shown in Fig. 6, the reservoir 23 may comprise a venting port 2334 for releasing a pressure in the secondary chamber 2332 as desired. Preferably, the venting port 2334 may be disposed at a top of the secondary chamber 2332. The skilled person in the art may understand that it is feasible for an operator to discharge the air/reduce the pressure via the venting port by means of a syringe.

According to an exemplary embodiment of the present disclosure, the secondary chamber 2332 may be offset relative to the primary chamber 2331. In the exemplary embodiment as shown in Fig. 4, the secondary chamber 2332 is offset relative to the primary chamber 2331 in a lateral direction (i.e., leftwards) away from the inlet 21. Preferably, respective lateral walls of the secondary chamber 2332 and the primary chamber 2331 are aligned with each other, as shown in Fig. 4.

The fluid channel 2333 may be closed in a similar manner to the upper flow path 1334 or the lower flow path 1335 in the first implementation and thus a further detailed description is omitted for brevity.

According to an exemplary embodiment of the present disclosure, the venting port 2334 may be configured to only allow the air to release outwards, which means that any liquid, if any, will not leak through the venting port 2334.

According to an exemplary embodiment of the present disclosure, the venting port 2334 may comprise a valve, for example a relief valve, to control or adjust releasing of the air via the venting port 2334.

According to an exemplary embodiment of the present disclosure, the venting port 2334 may comprise at least one hole. As an example, the at least one hole may comprise a plurality of micro holes, for example having a diameter of less than 5 microns, preferably generated by a laser.

According to an exemplary embodiment of the present disclosure, the venting port 2334 may be configured as a porous membrane, which may comprise a plurality of micro holes. The micro holes may be sized to prevent the liquid (if any) from leaking from the secondary chamber 2331 via the venting port 2334.

Below, operation or use of the air trap device 2 will be described in connection with Fig. 5 and Fig. 6, to better understand the air trap device 2.

During the priming phase, as shown in Fig. 5, the outlet 22 may be closed, the priming liquid may be filled into the air trap device 2 via the inlet 21 to generate a pressure within the primary chamber 2331 so as to compress all the air into the secondary chamber 2332 via the fluid channel 2333 and the fluid channel 2333 may be closed after priming to prepare for the treatment phase. As described above, the priming liquid will not enter the secondary chamber 2332 as the fluid channel 2333 only allows the air to enter into the secondary chamber 2332 from the primary chamber 2331.

During the priming phase, it may be ensured by any suitable measures that all the air is compressed into the secondary chamber 2332. For example, the pressure to be generated in the primary chamber 2331 can be calculated for example at least based on a volume of the priming liquid filled into the primary chamber 2331, and possibly in connection with a volume difference between the primary chamber 2331 and the secondary chamber 2332, and can be monitored by a pressure sensor (not shown) . It also may be understood by the skilled person in the art that a user can determine visually if all the air is compressed into the secondary chamber 2332 or the primary chamber 2331 is filled fully with the priming liquid, particularly in the case that the air trap device 2 is transparent.

During the treatment phase, as shown in Fig. 6, the blood flows into the air trap device 2 via the inlet 21 while the air within the secondary chamber 2332 is not allowed to flow back into the primary chamber 2331 via the fluid channel 2333, for example by closing the fluid channel 2333 (in Fig. 6, the fluid channel 2333 is closed schematically with a black block 16) . According to an exemplary embodiment of the present disclosure, during the treatment phase, the air within the secondary chamber 2332 may be released at least partially out of the secondary chamber 2332, for example via the venting port 2334.

It may be understood by the skilled person in the art that it is advantageous to reduce the pressure within the secondary chamber 2332.

Of course, it also is possible to release the air from the secondary chamber 2332 during the priming phase.

It may be understood easily from the above that during the treatment phase, the blood also is separated from any other liquid.

Fig. 7 schematically shows the air trap device 3 according to a third exemplary implementation of the present disclosure in a sectional view. As can be seen by comparison of Fig. 7 and Fig. 4, the air trap device 3 is similar to the air trap device 2. Also, in order to avoid unnecessary repetitive description, a focus will be placed mainly on some differences from the second exemplary implementation of the present disclosure as shown in Fig. 4 to Fig. 6. Of course, some features described in connection with Fig. 1 to Fig. 6 also may be used in the air trap device 3 without technical conflicts, although they may not be clearly stated below.

As shown in Fig. 7, the air trap device 3 also have a primary chamber 3331 and a secondary chamber 3332, between which a fluid channel 3333 is formed to fluidly communicate the primary chamber 3331 and the secondary chamber 3332. The air trap device 3 differs from the air trap device 2 mainly in that the fluid channel 3333 has different fluid flow characteristics compared with the fluid channel 2333, which will be further explained.

Fig. 7 actually schematically shows how the air trap device 3 works during a priming phase in which an outlet 32 is opened, the priming liquid has filled fully the entire primary chamber 3331 and a portion of the secondary chamber 3332 via an inlet 31. This means that the priming liquid can enter the secondary chamber 3332 from the primary chamber 3331 via the fluid channel 3333.

Fig. 8 schematically shows a treatment phase in which some air released from the blood has been trapped in a top area of the primary chamber 3331 and the priming liquid entering the secondary chamber 3332 during the priming phase is kept within the secondary chamber 3332. Thus, according to an exemplary embodiment of the present disclosure, the fluid channel 3333 may be configured to be able to keep the entering liquid within the secondary chamber 3332 without need of closing of the fluid channel 3333. That is to say, the fluid channel 3333 may be configured to allow the priming liquid to enter the secondary chamber 3332 from the primary chamber 3331, especially with the help of a pressure of the priming liquid and keep the entering priming liquid in the secondary chamber 3332, especially without the help of other external forces.

In this case, the air compressed into the secondary chamber 3332 during the priming phase will be trapped above the priming liquid kept within the secondary chamber 3332 so that the air is separated from the primary chamber 3331 by the kept priming liquid during the treatment phase. That is to say, during the treatment phase, the fluid channel 3333 may be covered by the priming liquid within the secondary chamber 3332 to prevent the trapped air within the secondary chamber 3332 from flowing back into the primary chamber 3331.

As shown in Fig. 8, especially with progress of the hemodialysis treatment, an air-blood level within the primary chamber 3331 becomes relatively lower and thus it is advantageous to cause some air trapped in the top area of the primary chamber 3331 to flow into the secondary chamber 3332 to increase the air-blood level within the primary chamber 3331.

As an exemplary embodiment of the present disclosure, as shown in Fig. 8, during the treatment phase, the outlet 32 may be closed to generate a pressure within the primary chamber 3331 to further compress the air trapped in the top area of the primary chamber 3331 into the secondary chamber 3332 and then the pressure is released, for example by opening the outlet 32, to push at least a part of the priming liquid within the secondary chamber 3332 back into the primary chamber 3331, which will make the air-blood level raised within the primary chamber 3331, as shown in Fig. 9. To achieve a better air separation effect, such an operation can be repeated to provide a minimal air-blood interface.

The fluid channel 3333 may be designed specially to have the above fluid flow characteristics, for example by considering some possible influencing factors, such as tension, viscosity, concentration, osmotic pressure and/or temperature of the related liquid, for example the priming liquid.

It may be understood by the skilled person in the art that the priming liquid may be pushed intentionally from the secondary chamber 3332 back into the primary chamber 3331 during the treatment phase, which does not mean uncontrollable mixing of the priming liquid and the blood during the treatment phase. Thus, the blood may be still separated from the priming liquid in a controllable manner during the treatment phase.

Fig. 10 schematically shows the air trap device 4 according to a fourth exemplary implementation of the present disclosure in a sectional view. As can be seen by comparison of Fig. 10 with Fig. 7 and Fig. 4 to Fig. 6, particularly Fig. 6, the air trap device 4 is similar to a combination of the air trap device 2 and the air trap device 3 to a certain extent. Similarly, in order to avoid unnecessary repetitive description, a focus will be placed mainly on some differences from the second and third exemplary implementations of the present disclosure as shown in Fig. 4 to Fig. 6 and Fig. 7 to Fig. 9 respectively. Of course, some features described in connection with Fig. 1 to Fig. 9 also may be used in the air trap device 4 without technical conflicts, although they may not be clearly stated below.

As shown in Fig. 10, the air trap device 4 may comprise a primary chamber 4331 (similar to the primary chamber 3331 of the third implementation as shown in Fig. 7) , a secondary chamber 4332 (similar to the secondary chamber 3332 of the third implementation as shown in Fig. 7) , and an additional chamber 4334 (similar to the secondary chamber 2332 of the second implementation as shown in Fig. 6) , wherein the primary chamber 4331 can be fluidly communicated with the secondary chamber 4332 via a fluid channel 4333 (similar to the fluid channel 3333 of the third implementation as shown in Fig. 7) , and the secondary chamber 4332 can be fluidly communicated with the additional chamber 4334 via another fluid channel 4335 (similar to the fluid channel 2333 of the second implementation as shown in Fig. 4 to Fig. 6) .

During the priming phase, the priming liquid may fill the entire primary chamber 4331 and at least a part (alower part) of the secondary chamber 4332 via an inlet 41, the air may be compressed into the additional chamber 4334 and possibly a top part of the secondary chamber 4332, and the priming liquid entering the secondary chamber 4332 may be kept in the secondary chamber 4332.

During the treatment phase, the blood may flow into the primary chamber 4331 via the inlet 41 and flow out of the primary chamber 4331 via an outlet 42, the priming liquid entering the secondary chamber 4332 during the priming phase may be kept in the secondary chamber 4332, and the air compressed during the priming phase may be trapped in the additional chamber 4334 and possibly in the top part of the secondary chamber 4332.

According to an exemplary embodiment of the present disclosure, like the venting port 2334 as shown in Fig. 6, a venting port 4336 may be provided to release a pressure in the additional chamber 4334 during the priming phase and/or the treatment phase.

According to an exemplary embodiment of the present disclosure, during the priming phase and/or the treatment phase, the secondary chamber 4332 may be fully filled with the priming liquid.

With the above detailed description, the skilled person in the art may completely understand other aspects, including structures and/or use or operation, of the air trap device 4 and thus a repetitive description is omitted herein.

The skilled person in the art may understand that the present disclosure also further provides a set for hemodialysis, comprising: an extracorporeal circuit, comprising a dialyzer and a tubing circuit for transferring the blood from and back to the patient; and the air trap device described above, which may be disposed at the venous return line of the tubing circuit or at the venous port of the dialyzer.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. The attached claims and their equivalents are intended to cover all the modifications, substitutions and changes as would fall within the scope and spirit of the disclosure.

Claims

An air trap device (1, 2, 3, 4) for hemodialysis, comprising:

an inlet (11, 21, 31, 41) ;

an outlet (12, 22, 32, 42) ; and

a reservoir (13, 23) , with which the inlet (11, 21, 31, 41) and the outlet (12, 22, 32, 42) are fluidly communicated;

wherein both the inlet (11, 21, 31, 41) and the outlet (12, 22, 32, 42) are disposed at a lower end of the reservoir (13, 23) relative to a vertical direction in use; and

wherein the reservoir (13, 23) is configured to define a cavity (133) comprising at least two chambers in which adjacent chambers can be fluidly communicated.
The air trap device (1, 2, 3, 4) according to claim 1, wherein

the reservoir (13, 23) is configured to separate blood from other liquid different from the blood in a controllable manner during a treatment phase of the hemodialysis; and/or

the at least two chambers are configured to form at least two flow channels which each lead to the outlet (12, 22, 32, 42) or are configured to control fluid flow characteristics between the adjacent chambers; and/or

the inlet (11, 21, 31, 41) is disposed at a bottom edge (131) of the reservoir (13, 23) so that the inlet (11, 21, 31, 41) is oriented downwards; and/or

the outlet (12, 22, 32, 42) is disposed at a lateral edge (132) of the reservoir (13, 23) so that the outlet (12, 22, 32, 42) is oriented laterally; and/or

the air trap device (1, 2, 3, 4) is configured to be disposed at a venous port of a dialyzer.
The air trap device (1, 2, 3, 4) according to claim 1 or 2, wherein

the air trap device (1, 2, 3, 4) is configured to be incorporated, preferably integrated, into a venous cap of the dialyzer; and/or

the inlet (11, 21, 31, 41) is disposed at a corner of the reservoir (13, 23) .
The air trap device (1) according to any one of claims 1-3, wherein

the at least two chambers comprise at least two first chambers arranged laterally side by side and each fluidly communicated between the inlet (11) and the outlet (12) .
The air trap device (2, 3, 4) according to any one of claims 1-3, wherein

the at least two chambers comprise at least two second chambers arranged one above of another.
The air trap device (1) according to claim 4, wherein

the air trap device (1) comprises a first pressure sensor for detecting a pressure within the cavity (133) and/or a first level detector for detecting a liquid level within the cavity (133) ; and/or

the at least two first chambers comprise a main channel chamber (1331) and a bypass channel chamber (1332) divided by a dividing wall (1333) ; and/or

the reservoir (13) comprises a dam (134) so that fluid entering via the inlet (11) must flow over a top (1341) of the dam (134) before further flowing downstream; and/or

upper ends of the at least two first chambers can be fluidly communicated with each other through an upper flow path (1334) , and lower ends of the at least two first chambers can be fluidly communicated with each other through a lower flow path (1335) .
The air trap device (1) according to claim 6, wherein

the upper flow path (1334) is configured to be closable; and/or

the lower flow path (1335) is configured to be closable; and/or

the dam (134) is configured to define an inlet channel (1342) , and the main channel chamber (1331) is disposed between the inlet channel (1342) and the bypass channel chamber (1332) ; and/or

the main channel chamber (1331) has a larger flow cross section than the bypass channel chamber (1332) .
The air trap device (2, 3, 4) according to claim 5, wherein

the at least two second chambers comprise a primary chamber (2331, 3331, 4331) and a secondary chamber (2332, 3332, 4332) disposed above the primary chamber (2331, 3331, 4331) and fluidly communicated with the primary chamber (2331, 3331, 4331) via a first fluid channel (2333, 3333, 4333) , wherein both the inlet (21, 31, 41) and the outlet (22, 32, 42) are fluidly communicated with the primary chamber (2331, 3331, 4331) .
The air trap device (2, 3, 4) according to claim 8, wherein

the first fluid channel (2333, 3333, 4333) is configured to be closable; and/or

the first fluid channel (2333) is configured to only allow air to enter the secondary chamber (2332) from the primary chamber (2331) via the first fluid channel (2333) ; or

the first fluid channel (3333, 4333) is configured to allow liquid to enter the secondary chamber (3332, 4332) from the primary chamber (3331, 4331) via the first fluid channel (3333, 4333) ; and/or

the primary chamber (2331, 3331, 4331) is configured to be larger than the secondary chamber (2332, 3332, 4332) , particularly in a cross-section; and/or

the reservoir (23) comprises a first venting port (2334) for releasing a pressure in the secondary chamber (2332) ; and/or

the air trap device (2, 3, 4) comprises a second pressure sensor for detecting a pressure within the primary chamber (2331, 3331, 4331) and/or the secondary chamber (2332, 3332, 4332) , and/or a second level detector for detecting a liquid level within the primary chamber (2331, 3331, 4331) and/or the secondary chamber (3332, 4332) ; and/or

the secondary chamber (2332, 3332, 4332) is offset relative to the primary chamber (2331, 3331, 4331) .
The air trap device (4) according to claim 8 or 9, wherein

the at least two second chambers further comprise an additional chamber (4334) disposed above the secondary chamber (4332) and fluidly communicated with the secondary chamber (4332) via a second fluid channel (4335) , wherein the second fluid channel (4335) is configured to only allow air to enter the additional chamber (4334) from the secondary chamber (4332) via the second fluid channel (4335) , and the first fluid channel (4333) is configured to allow liquid to enter the secondary chamber (4332) from the primary chamber (4331) via the first fluid channel (4333) .
The air trap device (4) according to claim 10, wherein

the reservoir comprises a second venting port (4336) for releasing a pressure in the additional chamber (4334) .
The air trap device (1, 2, 3, 4) according to any one of claims 6-11, wherein

the upper flow path (1334) is configured to be able to be closed by a first valve and/or a first motion; and/or

the lower flow path (1335) is configured to be able to be closed by a second valve and/or a second motion; and/or

the first fluid channel (2333, 3333, 4333) is configured to be able to be closed by a third valve and/or a third motion; or

the first fluid channel (3333, 4333) is configured to be able to keep the entering liquid within the secondary chamber (3332, 4332) without need of closing of the first fluid channel (3333, 4333) ; and/or

the second fluid channel (4335) is configured to be able to be closed by a fourth valve and/or a fourth motion; and/or

the first venting port (2334) and/or the second venting port (4336) is configured to only allow air to release.
The air trap device (1, 2, 3, 4) according to claim 12, wherein

at least one of the first motion, the second motion, the third motion and the fourth motion is implemented actively by a driver and/or passively implemented by deformation of a material of a respective portion of the reservoir (13, 23) ; and/or

the first fluid channel (3333, 4333) comprises at least one first hole sized to keep the entering liquid within the secondary chamber (3332, 4332) without need of closing of the first hole; and/or

the first venting port (2334) and/or the second venting port (4336) comprises a fifth valve or at least one second hole; and/or

the first venting port (2334) and/or the second venting port (4336) is configured as a porous membrane.
The air trap device (1, 2, 3, 4) according to claim 13, wherein

the driver comprises a plunger, preferably driven by a step motor and/or a pneumatic source; and/or

at least one of the first valve, the second valve, the third valve and the fourth valve is a phantom valve; and/or

the material comprises wax and/or shape memory alloy, and the deformation is caused by a temperature change of the material; and/or

the fifth valve is a relief valve, or the at least one second hole comprises a plurality of micro holes, for example having a diameter of less than 5 microns, preferably generated by a laser.
A set for hemodialysis, comprising:

an extracorporeal circuit, comprising a dialyzer and a tubing circuit for transferring blood from and back to a patient; and

the air trap device (1, 2, 3, 4) according to any one of claims 1-14, which is disposed at a venous return line of the tubing circuit or at a venous port of the dialyzer.
A method for operating the air trap device (1) according to claim 6 or 7, comprising:

a priming phase, in which a priming liquid is filled into the air trap device (1) via the inlet (11) without or with closing of the lower flow path (1335) , to flush out all air out of the outlet (12) ; and/or

a treatment phase, in which blood flows into the air trap device (1) via the inlet (11) and flows out of the air trap device (1) via the outlet (12) with opening of the lower flow path (1335) and without or with closing of the upper flow path (1334) .
The method according to claim 16, wherein

if the lower flow path (1335) is opened during the priming phase, the priming liquid, preferably saline is filled at a first flowrate, for example of more than 800 ml/min, higher than a second flowrate of the blood flowing into the air trap device (1) during the treatment phase; and/or

if the upper flow path (1334) is opened during the treatment phase, the blood flows into the air trap device (1) at a third flowrate than the first flowrate, for example of less than 500 ml/min.
A method for operating the air trap device (2, 3, 4) according to any one of claims 8-11, comprising:

a priming phase, in which the outlet (22) is closed, a priming liquid is filled into the air trap device (2) via the inlet (21) to generate a first pressure within the primary chamber (2331) so as to compress all air into the secondary chamber (2332) via the first fluid channel (2333) and the first fluid channel (2333) is closed after priming, or in which the outlet (32, 42) is opened, the primary chamber (3331, 4331) is filled fully with the priming liquid via the inlet (31, 41) and the secondary chamber (3332, 4332) is filled at least partially with the priming liquid from the primary chamber (3331, 4331) via the first fluid channel (3333, 4333) ; and/or

a treatment phase, in which blood flows into the air trap device (2, 3, 4) via the inlet (21, 31, 41) while the air within the secondary chamber (2332, 3332, 4332) is not allowed to flow back into the primary chamber (2331, 3331, 4331) via the first fluid channel (2333, 3333, 4333) .
The method according to claim 18, wherein

during the treatment phase, the first fluid channel (3333, 4333) is covered by the priming liquid within the secondary chamber (3332, 4332) to prevent the air within the secondary chamber (3332, 4332) from flowing back into the primary chamber (3331, 4331) ; and/or

during the priming phase, the first pressure is determined by calculating at least based on a volume of the priming liquid, for example saline, filled into the primary chamber (2331) and/or monitored by a pressure sensor; and/or

during the treatment phase and/or the priming phase, the air within the secondary chamber (2332, 3332, 4332) is released at least partially out of the air trap device (2, 3, 4) ; or

during the treatment phase, the outlet (32, 42) is closed and a second pressure is generated in the reservoir to compress the air within the primary chamber (3331, 4331) into the secondary chamber (3332, 4332) via the first fluid channel (3333, 4333) and then the second pressure is reduced so as to push at least a part of the priming liquid within the secondary chamber (3332, 4332) back into the primary chamber (3331, 4331) via the first fluid channel (3333, 4333) to increase an air-blood level in the primary chamber (3331, 4331) .
The method according to claim 19, wherein

during the priming phase and/or the treatment phase, the secondary chamber (4332) is fully filled with the priming liquid.