DEVICE FOR EXTRACORPORAL BLOOD TREATMENT

Description

AREA OF INVENTION

[0001] The invention relates to a pressure measuring device and a medical functional device that can be connected to the pressure measuring device. Furthermore, the invention relates to a method for filling the medical functional device, wherein the pressure measuring device can be used to measure the pressure in the filled medical functional device. BACKGROUND

[0002] Pressure measurements in liquid-carrying lines are required, for example, in dialysis technology to monitor the correct functioning of dialysis machines.

[0003] In hemodialysis, where blood is purified extracorporeally using a dialysis machine (an example of an extracorporeal blood treatment device), one or more pressure measuring devices may be provided at various points in the blood-carrying system. These include, for example: between a patient-side end of an arterial line and a pump that may be arranged along this arterial line (arterial pressure measuring device), between the pump and a dialyzer (pre-filter pressure measuring device), on a venous line by which the blood is returned from the dialyzer to the patient, between the dialyzer and an air separation chamber (post-filter pressure measuring device).

[0004] Various pressure sensors are used as pressure measuring devices. For example, pressure sensors are employed where the pressure is detected by measuring the deflection of an air- and liquid-impermeable membrane. Other pressure sensors utilize an air cushion positioned so that the air in the cushion is compressed when the pressure in the fluid-carrying line is higher, and the pressure can then be measured by a pressure sensor connected to this air cushion. A disadvantage of this latter solution is the presence of a blood-air interface during treatment. To protect the machine's air lines, such pressure measuring units with an air cushion often incorporate a pressure transmission element. This element features a hydrophobic membrane that is air-permeable when dry but impermeable to liquid.For the pressure measuring unit to function, this hydrophobic membrane must not be moistened, because then, when the pressure in the liquid-carrying line changes, the air cannot pass through the membrane and therefore the air in the air cushion can no longer be compressed.

[0005] However, in order to measure the pressure in a fluid-carrying line, the line must first be filled. In other words, the air in the line must be replaced with fluid. This process is called priming or filling in dialysis, and during this step, the patient is not yet connected to the dialysis machine, especially not to the arterial or venous lines. Removing as much air as possible from the lines is important because otherwise, air could be introduced into the patient's vein.

[0006] There are many solutions for this filling process. For example, the air can be separated via a pressure measuring unit with an air cushion, as described above, which also has an opening to the outside. In other words, during priming / filling, the air is displaced across the hydrophobic membrane towards the air pressure sensor and then discharged to the outside. During this process, the pressure measuring system is open to the outside.

[0007] EP1319417 describes a method for monitoring a fluid piping system connected to a medical instrument. This method can be carried out using a sensor line branching off from the upper end of a drip chamber, in which a gas sensor protector having a hydrophobic membrane and a gas pressure sensor at its end are arranged.

[0008] US2019250058 describes a pressure measuring device with a tubular pressure port having an internal chamfer adjacent to a deflectable diaphragm and / or a hydrophobic or superhydrophobic coating applied to at least a portion of the tubular pressure port, the internal chamfer and / or the deflectable diaphragm.

[0009] The object of the invention is to provide a novel pressure measuring device that fulfills the various functions of conventional pressure measuring devices without having their disadvantages. DESCRIPTION OF THE INVENTION

[0010] A pressure measuring device as defined in claim 1 comprises a hydrophobic membrane which is permeable to air in the dry state and impermeable to air in the humidified state, and a pressure sensor which is in mechanical contact with the hydrophobic membrane and which is configured to follow a movement of the membrane.

[0011] The pressure measuring device further comprises a first chamber located on a front side of the hydrophobic membrane and a second chamber located on a back side of the hydrophobic membrane.

[0012] The pressure sensor in the second chamber is located on the hydrophobic membrane.

[0013] The pressure sensor of the pressure measuring device can comprise a pressure measuring sensor, in particular a strain gauge sensor or a piezoelectric sensor. The pressure sensor can further comprise a substrate on which the pressure measuring sensor is arranged. The pressure measuring sensor can be arranged on the side of the substrate facing away from the hydrophobic membrane.

[0014] The support layer can have an elastic membrane. The edge of the support layer can be pre-tensioned and attached to the first or second chamber. The support layer can be attached to the hydrophobic membrane.

[0015] The first chamber of the pressure measuring device can be detachably attached to the second chamber together with the hydrophobic membrane.

[0016] The first chamber of the pressure measuring device, together with the hydrophobic membrane and the pressure sensor, can be detachably attached to the second chamber.

[0017] The pressure sensor of the pressure measuring device may further have a cable line to transmit an electrical signal to an evaluation unit, the cable line optionally having a connector unit for connecting and / or disconnecting the pressure sensor from the evaluation unit.

[0018] The first chamber of the pressure measuring device can have at least two channels, each closed at one end by the hydrophobic membrane. The at least two channels can be individually shut off.

[0019] A medical device may include at least one blood line and / or a dialyzer for use with the pressure measuring device, wherein the first chamber and the hydrophobic membrane are part of the medical device. Alternatively, the first chamber, the hydrophobic membrane, and the pressure sensor may be part of the medical device.

[0020] The medical device may include a tubing section designed for insertion into a peristaltic pump. The medical device may include an impeller for use in an impeller pump. The medical device may include a chamber with a diaphragm for use in a diaphragm pump. The pressure measuring device may be fluidically located upstream or downstream of the pump. The medical device may include an air separation chamber, with the pressure measuring device being fluidically located upstream or downstream of the air separation chamber. The medical device may include a dialyzer, with the pressure measuring device being located on the dialyzer.

[0021] A method for measuring pressure using the pressure measuring device comprises the following steps: Filling the blood tubing system with a liquid, displacing air in the blood tubing system through the hydrophobic membrane, wherein the hydrophobic membrane is wetted by the liquid so that it becomes airtight or becomes airtight in the area of ​​one of the at least two channels, and measuring the change in the position of the membrane, in particular its shape, by the pressure sensor.

[0022] The term "pressure measuring device" as used in this description means that it includes at least essential elements according to the invention for measuring pressure. The term is not to be understood as including all elements that are technically necessary to evaluate a pressure measurement, for example. For instance, the pressure sensor may be designed to measure a change in the curvature of the diaphragm. An evaluation unit that translates this curvature into a pressure value may be integrated into the pressure sensor itself, or it may be provided as a separate unit. In this case, the evaluation unit does not necessarily have to be part of the pressure measuring device.

[0023] The figures show: Fig. 1 schematically shows the setup of a pressure measuring device; Fig. 2 schematically shows an embodiment of the construction of a pressure sensor; Fig. 3schematically shows a layer structure of the pressure measuring device; Figs. 4a to 4c schematically show embodiments of a carrier layer; Fig. 5 schematically shows the setup of a pressure measuring device with a first and a second chamber; Figs. 6 and 7 schematically show how the pressure measuring device can be integrated into a disposable item and a treatment device; Figs. 8a and 8b schematically show embodiments of the mechanical coupling of a pressure sensor with a hydrophobic membrane; Fig. 9 schematically shows an embodiment of coupling a pressure sensor with a hydrophobic membrane using a vacuum; Fig. 10 schematically shows an embodiment of a treatment system with a pressure measuring device; Fig. 11 schematically shows an embodiment of a pressure measuring device in which the pressure measuring device is integrated into a cap of a dialyzer; Fig. 12schematically shows an embodiment of a pressure measuring device with multiple channels as the first chamber; Fig. 13 schematically shows an embodiment of a ventilation device; Fig. 14 schematically shows an embodiment of the channels in the form of flexible elements and the closing means of a ventilation device; Fig. 15 schematically shows an embodiment of the channels and the closing means in the form of a slide of a ventilation device; and Fig. 16 schematically shows the integration of a ventilation device into a cap of a dialyzer.

[0024] When describing the embodiments with reference to the figures, identical or comparable features are marked with the same reference symbols. Such identical or comparable features are not described again for each figure; instead, reference is made to the respective description sections in which these features have already been described.

[0025] Fig. 1Figure 1 shows a schematic diagram of a pressure measuring device. The pressure measuring device comprises a hydrophobic membrane 1 and a pressure sensor 2. The hydrophobic membrane 1 is permeable to air when dry and impermeable to air when moistened. It is also impermeable to water-based liquids, such as water, priming fluid, dialysate, or blood. The pressure sensor 2 is in mechanical contact with the hydrophobic membrane 1. This contact allows the pressure sensor 2 to detect movement of the membrane 1. This movement could be, for example, a movement of the edge of the hydrophobic membrane 1, causing it to bulge. The movement could also be translational.The movement of the hydrophobic membrane 1 can be caused, for example, by a change in pressure on the side facing away from the sensor (front side) of the hydrophobic membrane 1.

[0026] The pressure sensor 2 can, as in Fig. 2 The support layer 3 is shown schematically. The pressure sensor 4 of the pressure sensor 2 can be arranged on the support layer 3. The support layer 3 can be positioned between the pressure sensor 4 and the hydrophobic membrane 1. In other words, the pressure sensor 4 can be located on the side of the support layer 3 facing away from the hydrophobic membrane (the back side). The movement of the hydrophobic membrane 1 can be transmitted to the pressure sensor 4 via the support layer 3. The pressure sensor 4 of the pressure sensor 2 can be a strain gauge sensor or a piezoelectric sensor.

[0027] The term pressure measuring device describes a device used to determine pressure. The pressure measuring device may include a pressure sensor. The term pressure sensor describes a device that reacts to a change in pressure. The pressure sensor may include a substrate and a pressure-measuring sensor, where the term pressure-measuring sensor describes a device that changes when the pressure changes and can generate a signal.

[0028] The carrier layer 3 can be permanently or detachably connected to the pressure measuring sensor 4.

[0029] The support layer 3 can be permanently or detachably connected to the hydrophobic membrane 1.

[0030] The hydrophobic membrane 1 can, as in Fig. 3As shown schematically, at least one layer 5 must have or consist of a hydrophobic material. The hydrophobic material can be a hydrophobic plastic. For example, the hydrophobic plastic can be PTFE (polytetrafluoroethylene) or ePTFE (expanded polytetrafluoroethylene). The hydrophobic plastic can also be a polyolefin or a silicone.

[0031] The hydrophobic membrane 1 can consist of or have two or more layers, for example, a first layer 5 made of or containing the hydrophobic material and a second layer 6, which has a drainage and / or support function and consists of or contains fabric and / or nonwoven material that is weldable and / or adhesive. Alternatively, the hydrophobic membrane 1 can have additional layers or components besides the aforementioned layers. The first layer 5 can be connected to the second layer 6 either over its entire surface or only at its perimeter, for example, by welding or bonding.

[0032] The support layer 3 can also be the second layer 6 of the hydrophobic membrane 1, or the second layer 6 of the hydrophobic membrane 1 can be a layer that is present in addition to the support layer 3.

[0033] The support layer 3 can be a plastic layer. The support layer 3 can be, or may have, a thin, flexible ceramic layer. The support layer 3 has sufficient flexibility to transmit movements of the hydrophobic membrane 1.

[0034] In other words, the layer structure can be as follows: On the front side a hydrophobic membrane layer 5, optionally a layer 6 with drainage and / or support function arranged on top of that, optionally the carrier layer 3 arranged on top of that, and the pressure measuring sensor 4 arranged on top of that.

[0035] In the Figures 4a to 4cThe following schematic representations illustrate embodiments of the support layer 3. The support layer 3 can have a closed membrane 7. The term "closed" here means that the membrane has no macroscopic openings, but rather a homogeneous material across its surface. The closed membrane 7 can cover the entire surface of the hydrophobic membrane 1. Since, in this embodiment of the closed membrane 7, the air that passes through the hydrophobic membrane 1 must also pass through the closed membrane 7, the closed membrane 7 is air-permeable. In another embodiment, the closed membrane 7 can only partially cover the hydrophobic membrane. In such an embodiment, the closed membrane 7 can also be air-impermeable. The support layer 3 can also have or consist of an open membrane 8.The term "open" here means that the membrane has one or more macroscopic openings 9. The area of ​​the openings 9 can be on the order of 1 to 1000 square millimeters or on the order of 1 to 10 square centimeters. In one embodiment, the open membrane 8 can have a closed edge region, or in another embodiment, the opening can also encompass the edge region, as schematically shown in Figure 8. Fig. 4c shown, so that the opened membrane 8 is a bridge membrane 10.

[0036] The pressure measuring device can, as in Fig. 5The first chamber 11 is schematically represented. Part of the wall of the first chamber 11 can be sealed by the hydrophobic membrane 1. The hydrophobic membrane, or, if present, the second layer 6, can be fluid-tightly connected to the first chamber 11 at its outer edge. The connection can be made by gluing, welding, and / or crimping. The first chamber 11 can be made of a rigid plastic, for example, polypropylene or rigid PVC, or its wall can be made of this material. The first chamber 11 can be a flow-through chamber. The flow-through chamber can have two or more openings in its wall. The first chamber 11 can be a dead-end chamber. The dead-end chamber can have exactly one opening. The first chamber 11 can be part of a disposable item. The disposable item can be a tubing set, a cassette, or a dialyzer.The disposable item in question can be, in particular, a fluid piping system intended for dialysis treatment, such as hemodialysis, hemofiltration, hemodiafiltration, ultrafiltration, diaphragmatic dialysis, or peritoneal dialysis. The term "disposable item" means that the disposable item is attached to the treatment device by the user for each patient's treatment, and typically a new disposable item is used for each treatment. Normally, disposable items are intended for single use only for hygienic reasons; however, cost considerations, for example, can lead to their reuse. Crucially, a disposable item is not a permanent component of the treatment device but merely forms a functional unit with it during treatment. See also the description of [missing information]. Figures 6 and 7 referred.

[0037] The pressure sensor 4 can be connected to a processor 13 via a signal line 12. The processor 13 can be programmed to process a signal transmitted by the pressure sensor 4 and determine a pressure value from it. The processor 13 can forward this pressure value to another processor, which can be programmed to perform or initiate one or more process steps based on the pressure value. The processor 13 can also be programmed to execute the functions of the other processor itself. The processor 13 can be part of a control device. The control device can include the processor 13 and optionally the other processor, a memory, and a communication bus. The term "processor" is not limited to a single physical processor.Rather, the processor can also be a multi-core processor or other interconnected processors or processor components. The memory can be volatile and / or non-volatile memory, or a combination thereof. The data bus can serve for exchanging data between memory and processor. The control device can comprise the physical components of a computer known to those skilled in the art, which are necessary to run a program and thus control a medical device. In addition to the processors, memory, and communication bus mentioned above, such components can also include interfaces to the devices to be controlled, such as actuators, sensors, displays, wired and wireless communication systems, and the like.

[0038] The pressure measuring device indicates, as in Fig. 4 schematically shown, a second chamber 14 is arranged on the back side of the hydrophobic membrane 1.

[0039] The second chamber 14 can be at least partially sealed off by the hydrophobic membrane 1 and / or the second layer 6 and / or the support layer 3. The pressure sensor is located in the second chamber 14.

[0040] The second chamber 14 can be part of the treatment device or the disposable article. The second chamber 14 can be made of the same material as the first chamber 11 or of a different material. In particular, the second chamber 14, as part of the treatment device, can be made of or incorporate metal.

[0041] The Figures 6 and 7Figure 1 schematically shows how the pressure measuring device can be integrated into a disposable article 15 and a treatment device 16. The pressure measuring device can be designed such that the hydrophobic membrane 1 is separable from the pressure sensor 2. The hydrophobic membrane 1 and optionally the first chamber 11 can be part of the disposable article 15, and the pressure sensor 2 and optionally the second chamber 14 can be part of the treatment device 16. The treatment device 16 can include the signal line 12 and the processor 13. When the pressure measuring device is used, the pressure sensor 2 and the hydrophobic membrane 1 are mechanically coupled to each other, so that movement of the hydrophobic membrane 1 is transmitted to the pressure sensor 2. In an alternative embodiment, the hydrophobic membrane 1 and optionally the first chamber 11, the pressure sensor 2, and optionally the second chamber 14 are part of the disposable article.The signal line 12 is designed to be detachable and has a connector 17. The connector 17 has a first connection on the side of the disposable item and a second connection on the side of the treatment device 16. The treatment device 16 can include at least a portion of the signal line 12 and the processor 13. When the pressure measuring device is used, the first and second connections are connected together.

[0042] The coupling of the movement of the hydrophobic membrane 1 with the pressure sensor 2 can be achieved in various ways. During this movement, the hydrophobic membrane 1 is not permeable to air, i.e., it is in a wetted state. This can prevent or block pressure equalization across the hydrophobic membrane. This is described with reference to the Figures 8a and 8b described. Pressure here means the differential pressure across the hydrophobic membrane 1.

[0043] The hydrophobic membrane 1 or the second layer described above exhibits elasticity. This elasticity allows the hydrophobic membrane 1 or the second layer described above to conform to pressure. Elasticity means that the hydrophobic membrane 1 or the second layer described above is designed in such a way that a restoring force acts on the material, resulting in a flatter configuration when unloaded compared to when compressed. The term "flat" or "flatter" refers to a reduced bulge. The hydrophobic membrane 1 or the second layer described above can be prestressed. "Prestressed" means that the hydrophobic membrane 1 or the second layer described above is attached to a wall, causing the hydrophobic membrane 1 or the second layer described above to contract when the attachment to the wall is released.

[0044] The pressure sensor 2 can be directly connected to the hydrophobic membrane 1 or to the second layer described above, which is connected to the hydrophobic membrane 1. The hydrophobic membrane 1 and / or the second layer can be rigidly connected to a wall of the first chamber 11. If a high pressure is now applied (indicated by the long arrow in Figs. 8a and 8b The hydrophobic membrane, and if present, the second layer, bulges out and is thus stretched. This also stretches pressure sensor 2. If the pressure is reduced (shorter arrow) or brought down to zero (no arrow), the bulge and thus the stretching of the second sensor decreases.

[0045] Another embodiment, schematically depicted in Figure 8b , differs from that associated with Figure 8aThe described embodiment differs in that, in this embodiment, the pressure sensor 2 itself is attached to the wall of the first chamber 11 or the second chamber. In particular, the attachment can be a fastening of the support layer of the pressure sensor 2. The pressure sensor 2 can be elastically designed and / or pre-tensioned. For an explanation of these features, reference is made to the explanation of the hydrophobic membrane 1. In this embodiment, the pressure sensor 2 can be neither connected to the hydrophobic membrane 1 nor to the second layer described above. Furthermore, the hydrophobic membrane 1 and the second layer described above can be without pre-tension. In this embodiment, when a high pressure is applied, the airtight or moistened hydrophobic membrane 1 is pressed against the pressure sensor 2, causing it to bulge and thus allowing a pressure measurement.When the pressure decreases, the pressure sensor 2 contracts and the bulge decreases until, at a pressure of 0, the pressure sensor 2 is completely relaxed in the direction of the bulge. This embodiment is only suitable for measuring positive pressures, since at negative pressures the hydrophobic membrane 1 continues to expand in the opposite direction to the arrow. Figure 8Since there is no fixed coupling between the hydrophobic membrane 1 and the pressure sensor 2, the pressure sensor 2 does not follow the hydrophobic membrane 1. Such an embodiment is particularly well-suited for applications where only positive pressure values ​​are to be measured. An advantage of this embodiment is its relatively simple and cost-effective design, and, most importantly, the elimination of the coupling. It has been shown that otherwise, the coupling would need to be checked, for example, during treatment, which entails a corresponding investment in equipment, process engineering, and / or time. This embodiment can be used, for example, in combination with the [missing information] related to Fig. 6The described embodiment can be implemented. In this resulting embodiment, only the pre-tensioned, treatment-side pressure sensor needs to be brought into contact with the hydrophobic membrane during installation of the disposable article, and the positive pressures can then be measured.

[0046] In Fig. 9Another coupling option is shown schematically. In this embodiment, the pressure sensor 2 is coupled to the hydrophobic membrane 1 by means of a vacuum. With such a coupling, the pressure sensor can be detachably attached to the hydrophobic membrane 1. In this case, the pressure sensor 2 is impermeable to air, at least in a section of its surface. For this purpose, the treatment device 16 has a pump 18 and an air line 19, which can be connected to or is connected to the second chamber 14. Air can be extracted from the second chamber 14 using the pump 18. Optionally, the treatment device 16 can have one, more, or all of the following components: a control unit 20, a valve 21 for shutting off the air line 19, and a second pressure measuring device 22 for measuring the pressure in the second chamber 14.The controller can be connected to the pump 18, the valve 21, and the second pressure measuring device via signal lines. The controller 20 can be programmed to maintain the pressure value in chamber 14 and, if the pressure value in chamber 14 exceeds a limit value, to start the pump 18 and thus extract air from the second chamber 14. The processor 13, which can process the signal from the pressure sensor 2, can be integrated into the controller 20, so that the processor 13 is also programmed to process further program sections of the treatment device 16, or the processor 13 can be an independent processor and only communicate with the controller 20.

[0047] Pump 18 can be a separate pump for aspirating air. Pump 18 can also be used to pump a liquid, in particular dialysate in an extracorporeal blood treatment device, to an outlet 23 of the treatment device. This eliminates the need for a separate outlet for the gas to be discharged. For this purpose, the air line 19 can open into a liquid line 24, and pump 18 can be located downstream of the point of connection.

[0048] In Fig. 10Various embodiments of a treatment system 25 are schematically depicted. In this illustration, the previously described pressure measuring device is designated by reference number 26. The pressure measuring device can be arranged once, twice, three times, four times, or more than four times (not shown) at different positions. The pressure measuring devices 26 can each be identical or differ from one another according to the embodiments of the pressure measuring devices described above. The closed arrows (not labeled) are merely to illustrate how gas can be separated via the pressure measuring device during a filling process. The treatment system can comprise one or more disposable items and a treatment device. For an understanding of the terms disposable item and treatment device, reference is made to the explanations earlier in the text.The treatment system for extracorporeal blood treatment may comprise the following components, with the distinction between them being designed as part of a disposable item or as part of the treatment device indicated in parentheses below, this assignment being merely optional and not mandatory: a dialyzer 27 (disposable item), an arterial line 28 (disposable item) with one end connected to an inlet of the dialyzer 27, a venous line 29 (disposable item) with one end connected to an outlet of the dialyzer 27, wherein the inlet and outlet of the dialyzer are fluidically connected, a blood pump 30 (disposable item and treatment device) with which blood is pumped towards the dialyzer during treatment, wherein the blood pump can act on the arterial line.The blood pump 30 can, for example, be a peristaltic pump, wherein the pump actuator is part of the treatment device and a portion of the arterial line 28 is designed as a flexible hose element so that the actuator can act upon it. Alternatively, the blood pump can also be a diaphragm pump, wherein the diaphragm and the pump vessel are part of the arterial line 28 and the hydraulic, pneumatic, or mechanical actuator for moving the diaphragm is part of the treatment device. Alternatively, the blood pump 30 can be an impeller pump, in particular a magnetically driven impeller pump, in which the impeller is arranged within the arterial line 28, while the drive for the impeller, in particular the magnetic drive, is designed as part of the treatment device.Further elements may include: a dialysate supply line 31, which is connected at one end to the dialyzer 27, for supplying dialysate and / or fill fluid to the dialyzer 27; a dialysate discharge line 32, which is connected at one end to the dialyzer 27, for removing dialysate and / or fill fluid from the dialyzer 27, wherein the dialysate discharge line 32 is the line for fluid 24, as described in . Fig. 9As described, a vessel 33, for example a bag or a canister, may be connected via a line 34 to the arterial line 28 and / or the venous line 29, the bag containing a filling fluid. The dialysate supply line 31 may be connected via a line 36 to the arterial line 28 and / or the venous line 29. Substitution fluid may be supplied via line 36 during treatment in hemodiafiltration or hemofiltration therapy, and / or dialysate or filling fluid may be supplied during filling. The open arrows (unlabeled) are merely to illustrate how fluid may be transferred into the arterial line 28 and / or the venous line 29 and / or the dialyzer 27 during a filling procedure.

[0049] To fill a tubing system comprising arterial line 28, venous line 29, and dialyzer 27, the arterial line 28 and the venous line 29, with ends connected to the patient during treatment, can be connected directly to each other or via an adapter. The adapter can be a T-piece or a Y-piece, the third opening of which can be connected to the dialysate drain line 32. In addition to being drained via the pressure sensor 26, air can also be drained via this third opening.

[0050] To fill a tubing system comprising the arterial line 28, the venous line 29, and the dialyzer 27, one end of the arterial line 28 and one end of the venous line 28, each connected to the patient during treatment, can be individually connected to the line containing the dialysate drain line 32. For these connections to the line containing the dialysate drain line 32, the treatment device 25 can be provided with one or more ports that are fluidically connected to the dialysate drain line 32. In addition to being removed via the pressure measuring device 26, air can also be removed via the port(s).

[0051] To fill a tubing system comprising arterial line 28, venous line 29, and dialyzer 27, one end of arterial line 28 and one end of venous line 29, each connected to the patient during treatment, can be individually connected to vessel 33. In this embodiment, the blood pump can be controlled to draw fluid from vessel 33 into the tubing system. The blood pump can circulate the fluid in a circuit that includes vessel 33. In addition to being removed via the pressure measuring device 26, air can also be removed through the semipermeable membrane of dialyzer 27.

[0052] To fill a tubing system comprising the arterial line 28, the venous line 30, and the dialyzer 27, one end of the arterial line 28 can be connected to a connector along the venous line 29, and one end of the venous line 30 can be connected to the dialysate drain line 32. For connecting the venous line 30 to the dialysate drain line 32, a port can be provided in the treatment device 25, which is fluidically connected to the dialysate drain line 32. In addition to being removed via the pressure measuring device 26, air can also be removed via the port(s).

[0053] To fill a tubing system comprising arterial line 28, venous line 29, and dialyzer 27, one end of arterial line 28 can be connected to a connector along venous line 30, and one end of venous line 29 can be connected to vessel 33. In this embodiment, the blood pump can be controlled to draw fluid from vessel 33 into venous line 30. The blood pump can circulate the fluid in a circuit that does not include vessel 33. In addition to being removed via the pressure measuring device 26, air can also be removed through the semipermeable membrane of dialyzer 27.

[0054] It should be noted that each of the connections can be used for the additional removal of air, the removal of fluid from the piping system, and optionally, the flushing of the piping system. The blood treatment system can further be programmed so that the connections potentially usable for the additional removal of air can be shut off, with appropriately controllable shut-off elements being provided. The air can only be removed via the pressure measuring device until the fluid wets the hydrophobic membrane and renders it airtight. Subsequently, i.e., with the hydrophobic membrane wetted, the pressure measuring device can be configured to measure the pressure at a point in the piping system. In particular, the pressure measuring device can be configured to measure the pressure in a subsequent blood treatment.

[0055] The term "filling the piping system" does not mean that the entire system must be filled. Only sections of the piping system can be filled using the procedure and pressure measuring device described here.

[0056] The pressure measuring device(s) can be arranged between a patient-side end of the arterial line 28 and the blood pump 30 (arterial pressure measuring device), and / or between the blood pump 30 and the dialyzer 27 (pre-filter pressure measuring device), and / or on the venous line 29, in particular between the dialyzer 27 and an air separation chamber arranged on the venous line 29 or on the air separation chamber or with a separate port along the venous line 29 (night filter pressure measuring device), and / or on the dialyzer 27.

[0057] In Fig. 11Figure 1 schematically shows an embodiment in which the pressure measuring device is arranged in a cap 42 of a dialyzer 27. The dialyzer 27 has an inlet 38 for blood (during treatment), an outlet 39 for blood (during treatment), an inlet 40 for dialysate (during treatment), and an outlet 41 for dialysate (during treatment). The area between the blood inlet and blood outlet, which are fluidically connected (blood chamber), on the one hand, and the area between the blood inlet and dialysate outlet, which are fluidically connected (dialysate chamber), on the other hand, are separated from each other by a semipermeable membrane. The semipermeable membrane can be a bundle of hollow fibers. The blood outlet is optionally arranged at the top during filling. This arrangement is known and is used in various types of dialyzers.At its upper end, the dialyzer 27 can have a cap 42 with an opening 43, which is in fluidic communication with the area through which blood flows during treatment. The drain 39 for blood can be located in or on the cap 42. Air can escape through this opening 43 during filling. The pressure measuring device according to the invention can be provided on or as part of this cap 42. The cap 42 can be dome-shaped, and the pressure measuring device according to the invention can be located at the uppermost end of the dome. This allows air to rise in the dome and be directed to the pressure measuring device according to the invention.

[0058] Optionally, the blood pump 30 can be integrated into the dialyzer body in the part of the dialyzer 27 opposite the cap 42, so that the blood pump 30 and an area in which the hollow fibers are arranged form a single component. The blood pump 30 can, in particular, be an impeller pump or the impeller of an impeller pump.

[0059] A filling procedure using the blood treatment system may include the following steps, although not all of them need to be implemented: Connecting the piping system, which comprises the arterial line 29, the venous line 30, the dialyzer 27, and the pressure measuring device according to the invention, to a liquid source; filling the piping system with filling liquid from a filling liquid source, wherein this filling may include pumping the filling liquid from a dialysate-side chamber via a semipermeable membrane into a blood-side chamber of the dialyzer 27, wherein the pumping is carried out by a pump connected to the dialysate supply line 31, and / or aspirating the filling liquid from a dialysate-side chamber via a semipermeable membrane into a blood-side chamber of the dialyzer 27, wherein the aspirating is carried out by the blood pump 30, and / or aspirating the liquid from a vessel 33, wherein the aspirating is carried out by the blood pump 30.and / or suction of the filling fluid from a dialysate-side chamber via a semipermeable membrane into a blood-side chamber of the dialyzer 27 or the vessel 33, wherein the suction is carried out by a pump connected to the dialysate drain line 32, and separation of the air via the pressure measuring device during filling.

[0060] Air can be separated via the pressure measuring device until the hydrophobic membrane becomes moistened and airtight. The filling process can be detected and pumping stopped when the pressure measuring device detects that the pressure has risen above a predefined limit. Similarly, the filling process can be detected and suction stopped when the pressure measuring device detects that the pressure has fallen below a predefined limit.

[0061] In Fig. 12Another embodiment of the pressure measuring device is shown schematically. This differs from the other described embodiments in that the first chamber 11 has several channels which are closed off by the hydrophobic membrane 1. The other features correspond to the other features of the described embodiments.

[0062] In Fig. 13 Figure 1 schematically illustrates an embodiment of a ventilation device. This ventilation device differs from the one associated with... Fig. 12 The described pressure measuring device is distinguished by the fact that no pressure sensor 2 is provided. The ventilation device can have a sealing means 44 for each of the channels of the first chamber 11.

[0063] In Fig. 14 is an embodiment of the channels and the closing means of the ventilation device associated with Fig. 13The described ventilation device is shown schematically. The channels can have flexible sections, for example a hose, which can be closed, in particular pressed shut, by the closure element 44.

[0064] In Fig. 15 is an embodiment of the channels and the closing means of the ventilation device associated with Fig. 13 The described ventilation device is shown schematically. The closing device can be a slide valve, by which the channels can be closed one after the other by sliding the valve.

[0065] The ventilation system, described in connection with the Figures 11 to 13 , can be used instead of the pressure measuring device on or as part of the cap 42 of a dialyzer, as described in connection with Fig. 10 , be provided for. This embodiment is shown schematically in Fig. 16 depicted.

[0066] In connection with the Figures 13 to 16In the described embodiments of the ventilation device, the hydrophobic membrane 1 covers the multiple channels. In one embodiment of the ventilation device, the hydrophobic membrane 1 can cover the multiple channels and seal each of them separately, for example, by being firmly, airtight, and fluid-tightly connected to the wall of each individual channel at the channel opening, for example, by gluing, welding, or crimping. In another embodiment of the ventilation device, each of the multiple channels can be covered with a separate hydrophobic membrane, and each of the multiple channels can be sealed separately, for example, by being firmly, airtight, and fluid-tightly connected to the wall at the channel opening, for example, by gluing, welding, or crimping.

[0067] A filling method for a tubing system, particularly for filling arterial and / or venous lines, can also involve either a pressure measuring device with a hydrophobic membrane or a hydrophobic membrane without a pressure measuring device combined with an impeller pump as a blood pump and optionally a suction device for drawing fluid towards the hydrophobic membrane. Since the impeller pump, unlike a peristaltic pump, cannot pump air, the fluid must be transferred into the tubing system by a method other than pumping or suction using the impeller pump. The hydrophobic membrane cannot be a dialyzer membrane. The hydrophobic membrane can be a dialyzer membrane. The hydrophobic membrane can be positioned on a section of the tubing system to be filled.

[0068] In one version of the filling process, gravity can be used. For this purpose, a liquid source can be positioned above the piping system, and the liquid can fill the piping system with the impeller located within it.

[0069] In a further embodiment, which can be combined with the embodiment described above, the filling method can provide for generating a pressure gradient across the hydrophobic membrane, for example by means of the suction device, which can be part of the dialysate circuit of a dialysis machine. In particular, the suction device can be arranged on a dialysate discharge line of the dialysate circuit.

[0070] During the filling process, the air to be displaced can be completely or partially separated via the hydrophobic membrane. Once the piping system is filled to the point where the hydrophobic membrane is wetted, no further air can be separated via the hydrophobic membrane.

[0071] The dialysis machine may have a pressure measuring device for measuring the pressure in the dialysate drainage line. A control unit of the dialysis machine, configured to compare the pressure determined by the additional pressure measuring device with a limit value, can send a signal to the suction unit to stop the process if the control unit detects that the pressure has fallen below the limit value.

[0072] Alternatively or additionally, the dialysis machine can be equipped with another pressure measuring device to measure the pressure in the tubing section. A control unit of the dialysis machine, configured to compare the pressure determined by the additional pressure measuring device with a limit value, can send a signal to the suction unit to stop the process if the control unit detects that the limit value has been exceeded.

[0073] Alternatively or additionally, the control unit can cause the suction device to stop when a predetermined volume of liquid has been pumped by the suction device during filling.

[0074] The filling of the piping system can be divided into two phases: a first phase in which the impeller pump is not activated, and a second phase in which the impeller pump is activated. The first phase can correspond to a phase in which the impeller is surrounded by air, at least initially, and the second phase can correspond to a phase in which the impeller is surrounded by a liquid, at least temporarily. In other words, during filling, the air surrounding the impeller can first be replaced by liquid, and then, when liquid surrounds the impeller and a pumping action by the impeller is possible, the impeller pump can be operated and assist the filling process.

[0075] The transition from the first to the second phase can be volume-controlled. The dialysis machine's control system can be programmed to start the impeller pump after a predetermined volume has been transferred into the tubing.

[0076] Alternatively or additionally, a liquid detection device can be provided on one of the hose lines, particularly downstream of the impeller. The liquid detection device can, for example, detect optically, by ultrasound, or in another way that liquid is present in the hose assembly instead of air and, because it is located downstream of the impeller, that the impeller must be surrounded by liquid. The control system can receive the signal from the liquid detection device and be programmed to start the impeller pump when liquid is detected.

[0077] The impeller pump can be a pump in which the impeller is magnetically suspended, meaning that when activated, the impeller is held suspended in the liquid. Since in this situation the impeller does not come into mechanical contact with the surrounding walls, activating the pump can also reduce the risk of damage or wear to the impeller.

[0078] A suitable dialysis machine may have one, several, or all of the following features: a filling fluid source, for example a bag or canister or a connection to a dialyzer inlet; a section of tubing in a tubing system connected at one end to the fluid source and at the other end to a dialyzer; an impeller arranged in the tubing section; an impeller drive for driving the impeller; a hydrophobic membrane arranged along the tubing section, separating the interior of the tubing section from the exterior; a suction device fluidically connected to the hydrophobic membrane and configured to draw fluid from the tubing section through the hydrophobic membrane; a pressure measuring device for measuring the pressure in a line between the hydrophobic membrane and the suction device; alternatively or additionally, another pressure measuring device for measuring the pressure in the tubing section.a control device for starting and stopping the suction device and optionally for receiving the measured value of the pressure measuring device and optionally for starting the impeller drive, wherein the control device may be programmed to stop the suction device when the pressure transmitted by the pressure measuring device falls below a predetermined limit or from the ,

[0079] The pressure transmitted to another pressure measuring device rises above a predetermined limit.

Claims

1. Pressure measuring device having a hydrophobic diaphragm (1) that is permeable to air in the dry state and airtight in a moistened state, and a pressure sensor (2) that is in mechanical contact with the hydrophobic diaphragm (1) and configured to follow a movement of said diaphragm (1), a first chamber (11) arranged on a front side of the hydrophobic diaphragm (1), and a second chamber (14) arranged on a back side of the hydrophobic diaphragm (1), characterized in that the pressure sensor (2) is arranged in the second chamber (14) on the hydrophobic diaphragm (1).

2. Pressure measuring device according to Claim 1, wherein the pressure sensor comprises a pressure measuring sensor system (4), in particular a strain gauge sensor system or a piezoelectric sensor, and optionally comprises a support layer (3), on which the pressure measuring sensor system (4) is arranged on the side facing away from the hydrophobic diaphragm (1).

3. Pressure measuring device according to Claim 2, wherein the support layer (3) comprises an elastic diaphragm, the edge region of which is secured in prestressed fashion to the first chamber (11) or the second chamber (14), or wherein the support layer (3) is secured to the hydrophobic diaphragm (1).

4. Pressure measuring device according to any of the preceding claims, wherein together with the hydrophobic diaphragm (1), the first chamber (11) is detachably secured to the second chamber (14).

5. Pressure measuring device according to Claim 4, wherein together with the hydrophobic diaphragm (1) and the pressure sensor (2), the first chamber (11) is detachably secured to the second chamber (14).

6. Pressure measuring device according to any of Claims 1 to 4, wherein the pressure sensor (2) further comprises a cable line (12) for transmitting an electrical signal to an evaluation unit (13), wherein the cable line (12) optionally comprises a connector unit for establishing and / or breaking the connection between the pressure sensor (2) and the evaluation unit (13).

7. Pressure measuring device according to any of Claims 1 to 6, wherein the first chamber (11) comprises at least two channels, each of which is closed off at one end by the hydrophobic diaphragm (1).

8. Pressure measuring device according to Claim 7, wherein at least two of the at least two channels can be blocked on an individual basis.

9. Medical functional device comprising at least one blood line (28, 29) and / or a dialyser (27), for use with a pressure measuring device according to any of Claims 1 to 8, wherein the first chamber (11) and the hydrophobic diaphragm (1), or the first chamber (11) and the hydrophobic diaphragm (1) and the pressure sensor (2), are part of the medical functional device.

10. Medical functional device according to Claim 9, having a line section configured for insertion into a peristaltic pump or having an impeller pump or having a diaphragm pump, wherein the pressure measuring device is arranged fluidically upstream or downstream of the pump, and / or having an air separation chamber, wherein the pressure measuring device is arranged fluidically upstream or downstream of the air separation chamber, and / or having a dialyser (27), wherein the pressure measuring device is arranged at the dialyser (27).

11. Method for measuring a pressure using a pressure measuring device according to any of Claims 1 to 8, comprising: - filling the blood tube system (28, 29) with a fluid while displacing air in the blood tube system (28, 29) through the hydrophobic diaphragm (1), wherein the hydrophobic diaphragm (1) is wetted by the fluid such that it becomes impermeable to air or becomes impermeable to air in the region of one of the least two channels, and - measuring the change in the position of the diaphragm (1), in particular its shape, by the pressure sensor (2).