AUTOMATIC EMPTYING OF A DIALYSATOR AFTER BLOOD TREATMENT THERAPY

Description

[0001] The present disclosure relates to an extracorporeal blood treatment device, in particular a dialysis machine, for use in blood treatment therapy, comprising: an extracorporeal circuit; a dialyzer fluid circuit; and a dialyzer comprising a blood side which is fluidically connected to the extracorporeal circuit, and a dialyzer fluid side which is fluidically connected to the dialyzer fluid circuit, wherein the blood side of the dialyzer and the dialyzer fluid side of the dialyzer are separated from each other by a membrane provided in the dialyzer, and the extracorporeal blood treatment device further comprises a control unit which is designed to automatically empty the dialyzer after the end of the blood treatment therapy by setting a negative pressure orThe present disclosure relates to a method for automatically emptying a dialyzer after the end of a blood treatment therapy. This involves a negative pressure in the dialyzer fluid circuit and the associated transfer of fluid from the blood side across the dialyzer membrane into the dialyzer fluid side. Technical background

[0002] Following blood treatment therapy, in which a patient's blood is purified extracorporeally using a dialyzer and, if necessary, a dialyzer fluid flowing through the dialyzer, the patient's blood still circulating in an extracorporeal circuit, such as an arterial and venous tubing system (A / V tubing system), is returned to the patient. This process is called reinfusion. Only after the blood remaining in the extracorporeal circuit has been appropriately returned / reinfused to the patient is the patient completely disconnected from the extracorporeal tubing system (both arterial and venous). After reinfusion, there is always some (reinfusion) fluid remaining in the extracorporeal circuit, the dialyzer, etc.Before disposing of the tubing and dialyzer forming the extracorporeal circuit and the dialysis fluid circuit, these should be emptied, especially to reduce the (weight-dependent) disposal costs. State of the art

[0003] The prior art includes extracorporeal blood treatment devices that require several manual steps by the operator to empty a dialyzer after the end of blood treatment therapy and after reinfusion of the patient's blood. For example, it is known that the extracorporeal circuit or blood tubing system is first disconnected from the dialyzer and emptied into a bag or waste port of the blood treatment device. Subsequently, a dialyzer fluid inlet tube can be disconnected from the dialyzer, and any remaining fluid in the dialyzer can be at least partially aspirated via the dialyzer fluid outlet tube.

[0004] This semi-automatic emptying process requires several manual steps, which is a disadvantage. Nursing staff must interact with the extracorporeal blood treatment device multiple times, resulting in waiting time in front of the machine. Furthermore, while this emptying procedure effectively removes the remaining fluid from the dialysis fluid side of the dialyzer, it does not remove the blood-side fluid. Consequently, the dialyzer remains very heavy after emptying, leading to high disposal costs.

[0005] From EP 3 231 466 B1, an automated emptying of an extracorporeal circuit / AN tubing system and a blood side of the dialyzer is known. In this process, a negative pressure is created on the dialysis fluid side of the dialyzer, by means of which fluid is aspirated from the blood side of the dialyzer, so that the fluid passes through a membrane of the dialyzer from the blood side to the dialysis fluid side. The fluid transfer is assisted by a level control pump provided in the extracorporeal circuit.During the emptying process, the ends of the arterial section of the extracorporeal circuit and the venous section of the extracorporeal circuit are short-circuited, and at least one blood pump provided in the extracorporeal circuit is in operation, so that the fluid present in the short-circuited blood circuit is pumped in the direction of therapeutic flow into the blood side of the dialyzer, there, due to the pressure gradient, passes into the dialyzing fluid side of the dialyzer and is drawn off.

[0006] EP 3 231 466 B1 does not address the emptying of the dialyzer's fluid side. Therefore, it must be assumed that even after emptying the blood side of the dialyzer and the extracorporeal circuit as described in EP 3 231 466 B1, several manual steps are still required (disconnecting the extracorporeal circuit from the dialyzer, disconnecting the fluid inlet tubing from the dialyzer, and aspirating the remaining fluid from the dialyzer via the fluid outlet tubing). Thus, while the weight of the dialyzer can be reduced after emptying by applying the disclosure in EP 3 231 466 B1, several manual steps are still required by the user.

[0007] Finally, EP 1 996 253 B1 discloses a fully automatic method for emptying a dialyzer after blood treatment therapy. According to the disclosure in EP 1 996 253 B1, the blood side of the dialyzer and the extracorporeal circuit are first emptied in a manner similar to that described in EP 3 231 466 B1. Subsequently, the dialysis fluid side of the dialyzer is also automatically emptied. For this purpose, a (venting) valve located in the dialysis fluid inlet is opened. When a fluid pump located in the dialysis fluid outlet is then activated, air can flow into the dialyzer (optionally assisted by a compressor located in the dialysis fluid inlet), so that the remaining fluid on the dialysis fluid side of the dialyzer is transported towards the dialyzer outlet until the entire dialyzer is filled with air.

[0008] In EP 1 996 253 B1, an additional venting valve is required, which is disadvantageous, in order to provide fully automatic emptying of the dialyzer.

[0009] Both EP 1 996 253 B1 and EP 3 231 466 B1 disclose an extracorporeal blood treatment device according to the preamble of claim 1. Brief description of the Revelation

[0010] Against this background, the purpose of the present disclosure is to avoid or at least mitigate the disadvantages of the prior art. In particular, a dialyzer should be completely emptied automatically after the end of a blood treatment therapy in order to reduce the disposal weight of the dialyzer to a minimum. Furthermore, interaction of nursing staff with the extracorporeal blood treatment device should be reduced. In addition, preferably only the components already standardly present in an extracorporeal blood treatment device should be used / required for the automatic emptying.

[0011] This problem is solved by an extracorporeal blood treatment device according to claim 1 and a method for automatically emptying a dialyzer after the end of a blood treatment therapy according to claim 12. Advantageous further developments and embodiments are claimed in the dependent claims and / or are explained below.

[0012] The disclosure relates first to an extracorporeal blood treatment device for use in blood treatment therapy, comprising: an extracorporeal circuit; a dialysis fluid circuit; and a dialyzer comprising a blood side which is fluidically connected to the extracorporeal circuit, and a dialysis fluid side which is fluidically connected to the dialysis fluid circuit, wherein the blood side of the dialyzer and the dialysis fluid side of the dialyzer are separated from each other by a membrane provided in the dialyzer, and the extracorporeal blood treatment device further comprises a control unit which is designed to automatically empty the dialyzer after the end of the blood treatment therapy by setting a negative pressure or...The control unit is set up to create negative pressure in the dialysis fluid circuit, causing fluid to pass from the blood side across the dialyzer membrane into the dialysis fluid side. Once the fluid from the extracorporeal circuit has completely passed from the blood side across the dialyzer membrane into the dialysis fluid side, and the blood side of the dialyzer is empty, the control unit continues to maintain negative pressure in the dialysis fluid circuit. This causes air to pass from the blood side across the dialyzer membrane to the dialysis fluid side and displaces the fluid from the dialysis fluid side towards a dialysis fluid outlet (downstream of the dialyzer), thus automatically emptying the dialysis fluid side of the dialyzer.

[0013] According to the present disclosure, after the end of blood treatment therapy, the control unit preferably first controls a reinfusion of blood into the patient in such a way that a (dialysis) fluid is delivered from the dialyzer fluid circuit via the membrane of the dialyzer to the extracorporeal circuit, which during the reinfusion displaces the blood present in the extracorporeal circuit towards a patient in order to return the blood to the patient via both the venous and arterial segments.

[0014] Preferably, the control unit is configured to close an arterial tube clamp provided in the arterial section of the extracorporeal circuit and a venous tube clamp provided in the venous section of the extracorporeal circuit when reinfusion (both via the arterial section and via the venous section of the extracorporeal circuit) has been terminated.

[0015] It is advantageous that the patient is then disconnected both arterially and venously by nursing staff.

[0016] After the patient is disconnected, a patient-side end of the arterial section is preferably short-circuited or connected to a patient-side end of the venous section. This advantageously represents the last active interaction of the nursing staff with the extracorporeal blood treatment device. In other words, it is provided that a complete automatic emptying of the dialyzer, controlled by the control unit, is subsequently carried out without the need for the nursing staff to interact with the extracorporeal blood treatment device again.

[0017] Furthermore, it is advantageous if, during automatic emptying, the dialyzer is arranged or aligned on the extracorporeal blood treatment device in such a way that a dialyze fluid outlet, which is connected to the dialyze fluid outflow, is located (in a vertical direction of the extracorporeal blood treatment device) below a dialyze fluid inlet, which is connected to a dialyze fluid inflow.

[0018] In other words, during automatic emptying, the dialyzer is preferably arranged / oriented on the extracorporeal blood treatment device such that a dialyzer fluid outlet is located at the bottom and a dialyzer fluid inlet is located at the top. Particularly preferably, the dialyzer is vertically oriented, meaning that a longitudinal axis of the essentially cylindrical dialyzer preferably extends in a vertical direction (perpendicular to the Earth's surface).

[0019] If an extracorporeal blood treatment device is designed so that the dialyzer outlet is located at the top rather than the bottom during blood treatment therapy (for example, due to the countercurrent principle), nursing staff must rotate the dialyzer before automatic emptying, i.e., orient it so that the dialysis fluid outlet is at the bottom. This manual step, if necessary, can be performed by nursing staff in conjunction with short-circuiting the extracorporeal circuit, thus preferably avoiding any additional interaction that would require waiting time for the nursing staff.

[0020] Advantageously, following patient disconnection and any necessary rotation of the dialyzer, the blood side of the dialyzer is automatically emptied. In particular, the procedure described in EP 3 231 466 B1 can be used, which provides a suitable method for emptying the blood tubing system and the blood side of the dialyzer. Specifically, the control unit is configured to create negative pressure in the dialysis fluid circuit (on the dialysis fluid side), thereby aspirating any dialysis fluid present in the extracorporeal circuit (on the blood side).During emptying, the fluid (still present in the extracorporeal circuit) is preferentially supplied from the extracorporeal circuit to the dialyzer fluid circuit via the membrane of the dialyzer, until no more fluid is present in the extracorporeal circuit and the blood side of the dialyzer.

[0021] The core of the revelation is that the control unit is set up to control the emptying of the dialyzer in such a way that first the liquid and then (when the liquid from the extracorporeal circuit has completely passed across the membrane of the dialyzer from the blood side to the dialyzer fluid side, i.e., when there is no more liquid in the extracorporeal circuit and the blood side of the dialyzer) air passes from the extracorporeal circuit / blood side across the membrane of the dialyzer to the dialyzer fluid circuit / diayzer fluid side, so that the dialyzer fluid is also displaced from the dialyzer fluid side of the dialyzer towards the dialyzer fluid outlet by the passing air.

[0022] In particular, it has been shown according to the present disclosure that when the fluid from the extracorporeal circuit has completely passed from the blood side across the membrane of the dialyzer to the dialyzer fluid side, and the blood side of the dialyzer is emptied, by continuously adjusting the negative pressure or vacuum in the dialyzer fluid circuit (suction pressure on the dialyzer fluid side), air can be slowly drawn from the blood side across the membrane of the dialyzer to the dialyzer fluid side. If the dialyzer is now oriented such that the dialyzer outlet or dialyzer fluid outflow is at the bottom and the dialyzer inlet or dialyzer inlet is at the top, the resulting air will be drawn from the blood side across the membrane of the dialyzer to the dialyzer fluid side.Since the dialyzer fluid inlet is located at the top, the overflowing air collects in an upper section of the dialyzer (near the dialyzer inlet), displaces the fluid downwards towards the dialyzer outlet, and pushes the remaining fluid on the dialyzer side out of the dialyzer via the dialyzer outlet.

[0023] The control unit is thus designed to completely and automatically empty the dialyzer after the end of blood treatment therapy.

[0024] Preferably, the control unit is configured to generate the negative pressure or vacuum in the dialyzer circuit such that a flow pump output, which is a fluid pump in the dialyzer outlet of the dialyzer circuit (downstream of the dialyzer), is controlled to pump the liquid or air (from the blood side via the membrane of the dialyzer into the dialyzer side and finally) out of / away from the dialyzer into the dialyzer outlet.

[0025] Advantageously, the control unit is configured to control / operate a compressor pump provided in the extracorporeal circuit, so that it assists the passage of fluid and / or air from the blood side across the dialyzer membrane to the dialysis fluid side. In particular, the control unit is configured to control the compressor pump such that it forces the fluid and air across the dialyzer membrane.

[0026] Advantageously, the control unit is further configured to control or regulate the dialyzer's transmembrane pressure during automatic emptying to a pressure greater than a predetermined value and less than the dialyzer-specific maximum permissible transmembrane pressure. The maximum permissible transmembrane pressure depends in particular on the dialyzer type / dialyzer used and is generally specified in dialyzer data sheets.

[0027] Preferably, the control unit is configured to control or regulate the transmembrane pressure of the dialyzer to a pressure greater than 400 mmHg, preferably greater than 500 mmHg. For example, the control unit controls / regulates the transmembrane pressure to a pressure between 500 mmHg and 600 mmHg, for example 550 mmHg, but only if the maximum permissible transmembrane pressure is not exceeded at the set pressure. It is essential to ensure that the maximum permissible transmembrane pressure is not exceeded. Preferably, the extracorporeal blood treatment device of this disclosure may only use dialyzers whose maximum permissible transmembrane pressure is at least greater than 600 mmHg.

[0028] According to the present disclosure, it has been shown in particular that if a negative pressure is generated on the dialyzer fluid side (by actuating the flow pump outlet), possibly together with a positive pressure on the blood side (by actuating the compressor pump), such that a constant and high transmembrane pressure exists which lies in the range described above, air (relatively slowly) passes through the membrane of the dialyzer in an already emptied or emptied extracorporeal circuit and also displaces the dialyzer fluid still present on the dialyzer fluid side.

[0029] Preferably, the control unit is configured to automatically abort the emptying of the dialyzer fluid side using sensor control.

[0030] According to a preferred embodiment, the control unit is configured to evaluate a pressure signal or pressure profile from a pressure sensor arranged in the dialysis fluid outflow, which measures or monitors a pressure in the dialysis fluid outflow, and to abort the automatic emptying of the dialysis fluid side based on the pressure signal or pressure profile of the pressure sensor.

[0031] The control unit is preferably configured to evaluate the slope or first derivative of the pressure signal or pressure profile from the pressure sensor and to abort the automatic draining of the dialysis fluid side if the slope or first derivative of the pressure signal or pressure profile falls below a predetermined first limit value. In particular, it has been found, as disclosed, that air is present in the dialysis fluid drain when the slope / first derivative of the pressure signal or pressure profile from the pressure sensor becomes negative.

[0032] According to an alternative preferred embodiment, the control unit can also be configured to automatically abort the emptying of the dialysis fluid side in a sensor-controlled manner if an air separator provided or arranged in the dialysis fluid circuit detects or measures that a liquid level in the air separator has fallen below a predetermined liquid level.

[0033] Alternatively or additionally, the control unit can also be configured to terminate the automatic emptying of the dialyzer fluid side in a time-controlled manner. In particular, a control system that combines sensor-controlled termination with time-controlled termination is also conceivable.

[0034] Furthermore, the present disclosure relates to a method for automatically emptying a dialyzer after the end of a blood treatment therapy, in particular carried out or to be carried out in an extracorporeal blood treatment device as described above, comprising the steps of: setting a negative pressure or vacuum in a dialyzer fluid circuit and thereby allowing a fluid to pass from a blood side of the dialyzer, across a membrane of the dialyzer, to a dialyzer fluid side of the dialyzer; and, when the fluid from an extracorporeal circuit has completely passed from the blood side, across the membrane of the dialyzer, to the dialyzer fluid side and the blood side of the dialyzer has been emptied, continuing to set the negative pressure or vacuum.Negative pressure in the dialysis fluid circuit to cause air to pass from the blood side across the membrane of the dialyzer to the dialysis fluid side and to displace the fluid from the dialysis fluid side of the dialyzer towards a dialysis fluid drain, in order to automatically empty the dialysis fluid side of the dialyzer.

[0035] Preferably, the method further comprises the following step: Arranging or aligning the dialyzer during automatic emptying of the same on the extracorporeal blood treatment device such that a dialyzing fluid outlet, which is connected to the dialyzing fluid outflow, is arranged (in a vertical direction of the extracorporeal blood treatment device) below a dialyzing fluid inlet, which is connected to a dialyzing fluid inflow.

[0036] It is advantageous if the method also includes the following step: generating the negative pressure or vacuum in the dialyzer circuit by pumping the liquid or air out of the dialyzer into the dialyzer outlet by means of a flow pump outlet, which is a fluid pump in the dialyzer outlet of the dialyzer circuit.

[0037] Preferably, the method further comprises the following step: assisting the passage of the liquid or air from the blood side across the membrane of the dialyzer to the dialyzing fluid side by means of a compressor pump provided in the extracorporeal circuit.

[0038] In particular, the method also includes the following step: controlling or regulating the transmembrane pressure of the dialyzer to a pressure that is greater than a predetermined value and less than a dialyzer-specific maximum permissible transmembrane pressure. Preferably, the method additionally includes the step of controlling or regulating the transmembrane pressure of the dialyzer to a pressure that is greater than 400 mmHg, preferably greater than 500 mmHg.

[0039] It is advantageous if the procedure also includes the following step: Sensor-controlled termination of the automatic emptying of the dialyzer fluid side.

[0040] Preferably, the method further comprises the following steps: evaluating a pressure signal or pressure profile of a pressure sensor arranged in the dialysis fluid outflow, which measures or monitors a pressure in the dialysis fluid outflow, and aborting the automatic emptying of the dialysis fluid side based on the pressure signal or pressure profile of the pressure sensor.

[0041] Preferably, the method further includes the steps of: evaluating the slope or first derivative of the pressure signal or pressure profile of the pressure sensor, and aborting the automatic emptying of the dialysis fluid side if the slope or first derivative of the pressure signal or pressure profile falls below a predetermined first limit value.

[0042] Alternatively, the method preferably includes the step of: sensor-controlled termination of the automatic emptying of the dialysis fluid side when it is detected or measured by an air separator provided or arranged in the dialysis fluid circuit that a liquid level of the air separator has fallen below a predetermined liquid level.

[0043] Alternatively or additionally, the method preferably includes the following step: Time-controlled termination of the automatic emptying of the dialyzer fluid side.

[0044] When the procedure described is performed, preferably one end of the arterial segment of the extracorporeal circuit is connected to one end of the venous segment of the extracorporeal circuit, so that the patient is already disconnected. The procedure described therefore does not involve any surgical or therapeutic treatment of the human body. Brief description of the characters

[0045] The present revelation will be further explained below using figures. They show: Fig. 1 an extracorporeal blood treatment device according to the present disclosure during blood treatment therapy or during reinfusion; Fig. 2 the extracorporeal blood treatment device according to the present disclosure during automatic emptying of a dialyzer; Fig. 3 a detailed view of the dialyzer in a state in which one blood side of the dialyzer has already been completely emptied; Fig. 4 a detailed view of the dialyzer in a state in which one dialyzer fluid side of the dialyzer is currently being emptied; Fig. 5 a diagram showing a pressure signal or pressure profile of a pressure sensor arranged in the dialyzer fluid outlet over time; Fig. 6 a diagram showing a first derivative of the pressure signal or pressure profile of the pressure sensor over time; and Fig.7. A table specifying the required time and remaining disposal weight for various dialyzer emptying procedures. Character description

[0046] The figures are purely schematic and serve solely to aid in understanding the revelation. Identical elements are marked with the same reference symbols. The characteristics of the individual examples can be interchanged unless explicitly stated otherwise.

[0047] Fig. 1 Figure 2 shows an extracorporeal blood treatment device (dialysis machine) during blood treatment therapy or during reinfusion, i.e. before the automatic emptying as shown.

[0048] The extracorporeal blood treatment device 2 basically contains an extracorporeal circuit (A / V tubing system) 4, a dialyzer 6 and a dialyzer fluid circuit 8. A blood side 9 of the dialyzer 6 is separated from a dialyzer fluid side 11 of the dialyzer 6 by a (hollow fiber) membrane 10.

[0049] The extracorporeal circuit 4 contains an arterial section 12, which is located upstream of the dialyzer 6, and a venous section 14, which is located downstream of the dialyzer 6.

[0050] As from Fig. 1 As can be seen, the arterial section 12 and the venous section 14 are connected to a patient 15. In other words, one end of the arterial section 12 is connected to an artery of patient 15 and one end of the venous section 14 is connected to a vein of patient 15.

[0051] In the venous section 14 of the extracorporeal circuit 4, a venous expansion chamber or air trap 16, a venous safety air detector 18 and a venous hose clamp 20 are provided downstream of the dialyzer 6 (i.e. starting from the dialyzer 6 in a direction towards the end of the venous section 14).

[0052] In the arterial section 12, extending from the patient-side end of the arterial section 12 in a direction towards the dialyzer 6, an arterial hose clamp 22, an arterial safety air detector 24, and an (arterial) blood pump 26 are provided. As shown in Fig. 1 As can be seen, the extracorporeal circuit 4 (in particular a blood pump adapter thereof) is already inserted into the blood pump 26, which is preferably designed as a roller pump or peristaltic pump and is set up to pump a fluid by squeezing a tube.

[0053] In the arterial section 12, an arterial pressure upstream of blood pump 26 can be measured using an arterial pressure sensor 28. Furthermore, a dialyzer inlet pressure downstream of blood pump 26 and upstream of dialyzer 6 (between dialyzer 6 and blood pump 26) can be measured using a dialyzer inlet pressure sensor 30. In the venous section 14, a venous pressure at / downstream of the venous expansion chamber or air trap 16 can be measured using a venous pressure sensor 32. The pressure sensors 28, 30, and 32 provided in the extracorporeal circuit 4 can measure / receive / monitor the pressure at the corresponding locations in the extracorporeal circuit 4 where they are located.

[0054] As from Fig. 1As can be further seen, behind the arterial pressure sensor 28, the dialyzer inlet pressure sensor 30 and the venous pressure sensor 32 there is a compressor pump or a level control pump (LRP) 34 with associated valves 36, 38, 40, namely a first valve 36 between the arterial pressure sensor 28 and the compressor pump 34, a second valve 38 between the dialyzer inlet pressure sensor 30 and the compressor pump 34, and a third valve 40 between the venous pressure sensor 32 and the compressor pump 34.

[0055] The dialyzer fluid circuit 8 comprises a dialyzer inlet valve 42, a dialyzer outlet valve 44, a flow pump inlet 46, a flow pump outlet 48, and a pressure sensor 50. The dialyzer inlet valve 42 and the flow pump inlet 46 are located at a dialyzer fluid inlet 52 upstream of the dialyzer 6. The pressure sensor 50, the dialyzer outlet valve 44, and the flow pump outlet 48 are located at a dialyzer fluid outlet 54 downstream of the dialyzer 6. The flow pump inlet 46 and the flow pump outlet 48 are preferably gear pumps. The dialyzer fluid inlet 52 is connected to a dialyzer inlet 56 of the dialyzer 6. The dialyzer fluid outlet 54 is coupled to a dialyzer outlet 58 of the dialyzer 6.

[0056] The extracorporeal blood treatment device 2 further comprises a control unit 60, which is preferably configured as a processor, in particular as a central processing unit (CPU). The control unit 60 is preferably integrated into the extracorporeal blood treatment device 2, i.e., not separate from it. The control unit 60 receives information from sensors provided in the extracorporeal blood treatment device 2. The following are merely examples: Fig. 1The sensors shown include the arterial pressure sensor 28, the dialyzer inlet pressure sensor 30, the venous pressure sensor 32, the arterial safety air detector 24, the venous safety air detector 18, the pressure sensor 50, etc. On the other hand, the control unit 60 controls or actuates actuators which are provided in the extracorporeal blood treatment device 2. The following are merely examples: Fig. 1 The valves, pumps, hose clamps, etc. shown, in particular the dialyzer inlet valve 42, the dialyzer outlet valve 44, the flow pump inlet 46, the flow pump outlet 48, the (arterial) blood pump 26, the arterial hose clamp 22, the venous hose clamp 20, etc.

[0057] After the blood treatment therapy has ended, the control unit 60 first controls a reinfusion of blood into patient 15 such that a (dialysis) fluid is delivered from the dialysis fluid circuit 8 via the membrane 10 of the dialyzer 6 to the extracorporeal circuit 4. During the reinfusion, this fluid displaces the blood still present in the extracorporeal circuit 4 towards patient 15, in order to return the blood to patient 15 via both the venous section 14 and the arterial section 12. Advantageously, an overpressure is created on the dialysis fluid side 11 to force the fluid across the membrane 10 of the dialyzer 6 into the blood side 9. Additionally, a negative pressure can be created on the blood side 9 to also draw the fluid across the membrane 10 of the dialyzer 6 into the blood side 9.

[0058] To terminate the reinfusion via both the arterial section 12 and the venous section 14 of the extracorporeal circuit 4 (when the blood has been completely reinfused), the control unit 46 closes the arterial tube clamp 22 and the venous tube clamp 20. Subsequently, a nurse disconnects the patient 15 both arterially and venously.

[0059] Fig. 2 The extracorporeal blood treatment device (dialysis machine) 2 is shown during the automatic emptying of the dialyzer 6. It can be seen that after disconnecting the patient 15, the arterial section 12 and the venous section 14 are short-circuited or fluidically connected to each other, for example via a connector / adapter 62. The dialyzer 6 was rotated by a nurse to enable its automatic emptying, so that in Fig. 2The dialyzer outlet 58 is located at the bottom and the dialyzer inlet 56 at the top. The dialyzer 6 is advantageously oriented vertically during automatic emptying.

[0060] The control of the automatic emptying of the dialyzer 6, carried out by the control unit 60, is described with reference to Fig. 2 described.

[0061] Preferably, the control unit 60 is configured to first generate or establish a negative pressure on the dialysis fluid side 11 of the dialyzer 6. For this purpose, the control unit 60 activates the flow pump outlet 48, which pumps the fluid present in the extracorporeal circuit 4 and in the blood side 9 of the dialyzer 6 into the dialysis fluid side 11 of the dialyzer 6 and out of the dialyzer 6 into the dialysis fluid outlet 54. The flow pump inlet 46 is preferably stopped, the dialyzer inlet valve 42 is closed, and the dialyzer outlet valve 44 is open.

[0062] Furthermore, the control unit 60 can control the compressor pump 34 to assist the transfer of fluid from the blood side 9, across the membrane 10 of the dialyzer 6, to the dialysis fluid side 11. To achieve this, the compressor pump 34 preferentially injects air into the extracorporeal circuit 4. For example, the third valve 40 is opened while the first valve 36 and the second valve 38 remain closed, and the compressor pump 34 pumps air into the venous expansion chamber / air trap 16 (air supply is controlled / regulated via the venous pressure sensor 32). This introduction of air into the extracorporeal circuit 4 creates pressure within the circuit, and the fluid still present in the circuit is also forced across the membrane 10 of the dialyzer 6 from the blood side 9 to the dialysis fluid side 11.

[0063] According to the present disclosure, actuation of the compressor pump 34 during automatic emptying of the dialyzer 6 is optional, i.e., not absolutely necessary.

[0064] In any case, the control unit 60 is configured to control or regulate the transmembrane pressure of the dialyzer 6 to a constant, high value. It has been found in particular that the transmembrane pressure should be greater than 400 mmHg, especially greater than 500 mmHg, for example, 550 mmHg. The control unit 60 can only control / regulate the transmembrane pressure by activating the flow pump output 48 (for example, by changing its flow rate). In other words, only a suitable negative pressure can be generated on the dialysis fluid side 11. Alternatively, a positive pressure can also be generated on the blood side 9 by additionally activating the compressor pump 34.

[0065] The control unit 60 controls or regulates the transmembrane pressure in such a way that the maximum permissible transmembrane pressure of the dialyzer 6 used, which is entered or read in by a user before blood treatment therapy and is therefore known to the blood treatment device 2, in particular to the control unit 60, is not exceeded. This prevents, in particular, hollow fibers of the membrane 10 from rupturing and thus prevents any blood particles still present in the fluid from passing into the dialyzing fluid side 11.

[0066] When the fluid from the extracorporeal circuit 4 has completely passed from the blood side 9 across the membrane 10 of the dialyzer 6 to the dialysis fluid side 11, and the blood side 9 of the dialyzer 6 is emptied, the existing negative pressure on the dialysis fluid side 11, or in particular the controlled / regulated transmembrane pressure, is maintained, according to the present disclosure. In particular, it has been shown, according to the disclosure, that if the transmembrane pressure is controlled / regulated to such a high value, both fluid and air can be transported across the membrane 10 of the dialyzer 6. At this point at the latest, the dialyzer outlet 58 must be directed downwards.Due to the prevailing negative pressure and an emptied extracorporeal circuit 4, air now passes through the membrane 10 of the dialyzer 6 and displaces the liquid still present in the dialyzer 6 from the dialyzer fluid side 11 towards the dialyzer fluid outlet 54. The air passage is also preferentially supported by the compressor pump 34.

[0067] Fig. 3 shows a detailed view of the dialyzer 6 in a state in which the blood side 9 of the same is already completely emptied. Fig. 4 Figure 1 shows a detailed view of the dialyzer 6 in a state where the dialyzing fluid side 11 is being emptied. As can be seen in particular from the following: Fig. 4 The air that has passed over initially collects in an upper section of the dialyzer 6 (in the area of / near the dialyzer inlet / s 56) and displaces the liquid downwards towards the dialyzer outlet 58.

[0068] The control unit 60 is preferably configured to terminate the automatic emptying of the dialyzer 6 when the dialyzer fluid side 11 of the dialyzer 6 is also completely empty. Preferred termination criteria of the present disclosure are first defined by reference to Fig. 3 and Fig. 4 described.

[0069] In principle, according to the present disclosure, a time-controlled termination of the automatic emptying process is conceivable. For example, the control unit 60 can detect, based on sensor data transmitted to it, when the blood side 9 of the dialyzer 6 is completely empty. If the control unit 60 knows how long it usually takes to empty the dialyzer fluid side 11 for the dialyzer 6 being used at the set transmembrane pressure, the control unit 60 can terminate the automatic emptying process when a corresponding time interval has elapsed.

[0070] Particularly preferred according to the present disclosure is a sensor-controlled termination of the automatic emptying of the dialyzing fluid side 11 of the dialyzer 6. In this case, the control unit 60 advantageously evaluates a pressure signal or a pressure profile of the pressure sensor 50 arranged in the dialyzing fluid outlet 54.

[0071] Alternatively, the sensor-controlled termination of the automatic emptying can also be achieved via an air separator 64 provided in the dialysate circuit 8, in particular the dialysate outlet 54. During blood treatment therapy, the air separator 64 serves to remove air from the dialysate and protects the flow pump outlet 48 from unwanted air ingress. The air separator 64 is equipped with at least one liquid level sensor 66. When the liquid level sensor 66 of the air separator 64 detects that the liquid level in the air separator 64 has fallen below a predetermined liquid level, this means that air has entered the air separator 64 via the dialysate outlet 54, and thus the dialysate side 11 of the dialyzer 6 has also been emptied.

[0072] Since a relatively long hose section (approximately 1 meter) exists between the dialyzer 6 and the air separator 64 in practice, it takes a very long time for the automatic emptying to be aborted when the air separator 64 is used for sensor-controlled aborting. Against this background, the use of the pressure sensor (PDA) 50 is generally preferred with regard to sensor-controlled aborting according to the present disclosure. This is because the time it takes for the pressure change to propagate through the hose section is significantly shorter than the time it takes for air to enter the air separator 64 via the dialyzer fluid outlet 54. Even if both Fig. 3 as well as Fig. 4Although the figures are essentially schematic views, it is intended to illustrate that the pressure sensor 50 and the air separator 64 are arranged remotely from the dialyzer 6. According to the disclosure, it is also possible for the air separator 64 and the pressure sensor 50 to be combined in a single component, as shown in Fig. 3 and Fig. 4 as indicated.

[0073] The sensor-controlled termination of the automatic emptying of the dialyzer fluid side 11 of the dialyzer 6 is described in more detail with reference to Fig. 5 and Fig. 6 described. This shows Fig. 5 a diagram showing the pressure signal or pressure profile of pressure sensor 50 over time. Fig. 6 shows a diagram in which a slope / first derivative / gradient of the pressure signal or the pressure profile of the pressure sensor 50 is shown over time.

[0074] The control unit 60 preferentially monitors the pressure measured by the pressure sensor (PDA) 50 towards the end of the emptying process, for example from about 200 seconds onwards. Fig. 5 or Fig. 6 When the dialyzer 6 is completely emptied, air enters the dialyzer fluid outlet 54. This is accompanied by a drop in pressure in the dialyzer fluid outlet 54, which is measured by the pressure sensor (PDA) 50. Fig. 5 and Fig. 6 It is evident that the pressure measured by pressure sensor 50 remains almost constant during emptying. The same applies accordingly to the slope of the pressure signal. After approximately 1200 seconds, the signal begins to... Fig. 5 to fluctuate. This is an indication that air is now (also) present at pressure sensor 50. The slope of the pressure signal also changes (see Fig. 6According to the present disclosure, it has been found that the termination of the automatic emptying of the dialyzer 6 is best carried out based on the slope or first derivative of the pressure signal. If the slope falls below a certain predetermined negative value x, which is preferably set between -3 and -5, preferably to (approximately) -4, the termination criterion is met. This is in Fig. 6 This is the case at time t1.

[0075] Fig. 7 Finally, a table is shown showing the required time and remaining disposal weight for various dialyzer emptying procedures. The same dialyzer ("Xevonta Hi23") was used for all tests.

[0076] In the experiment designated "S1", the extracorporeal circuit or blood tubing system was first disconnected from the dialyzer and emptied into a bag or a waste port of the blood treatment device. Subsequently, a dialysate inlet was disconnected from the dialyzer, and any remaining fluid in the dialyzer was at least partially aspirated via the dialysate outlet. This emptying procedure took only 43 seconds. The disposal weight was 543.8 grams.

[0077] In the experiment designated "S2", the dialyzer was emptied as described in the prior art of EP 1 996 253 B1, i.e., via a valve provided in the dialyzer inlet. This emptying procedure took 154 seconds. The disposal weight was 381.1 grams.

[0078] In the experiment designated "S3", the dialyzer was emptied according to the present disclosure, whereby the automatic emptying of the dialyzer was interrupted by a sensor-controlled process via the pressure sensor in the dialyzer outlet. This emptying procedure was found to take 493 seconds. The disposal weight could be reduced to 359.2 grams.

[0079] In the experiment designated "S4", the dialyzer was emptied according to the present disclosure, whereby a sensor-controlled interruption of the automatic emptying of the dialyzer via the air separator in the dialyzer outlet was performed. This emptying procedure was found to take 573 seconds. The disposal weight could be reduced to 357.9 grams.

[0080] It has thus been shown that, according to the present disclosure (see experiments "S3" and "S4"), a reduction in disposal weight compared to the prior art is possible (this applies particularly to experiment "S1", but also to experiment "S2"). Although emptying the dialyzer according to the present disclosure takes a long time, this disadvantage is readily accepted in light of the achievable savings in disposal costs. Furthermore, the longer duration is not a significant factor in practice. This is because the dialyzer is emptied automatically (i.e., without intervention by nursing staff), and ultimately only the time after a patient is disconnected, specifically until they have left their treatment station, is used. Reference symbol list

[0081] 2 Extracorporeal blood treatment device / dialysis machine 4 Extracorporeal circuit 6 Dialyzer 8 Dialysis fluid circuit 9 Blood side 10 Membrane 11 Dialysis fluid side 12 Arterial section 14 Venous section 15 Patient 16 Venous expansion chamber / Air trap 18 Venous safety air detector 20 Venous hose clamp 22 Arterial hose clamp 24 Arterial safety air detector 26 Blood pump 28 Arterial pressure sensor 30 Dialyzer inlet pressure sensor 32 Venous pressure sensor 34 Compressor pump 36 First valve 38 Second valve 40 Third valve 42 Dialyzer inlet valve 44 Dialyzer outlet valve 46 Flow pump inlet 48 Flow pump outlet 50 Pressure sensor 52 Dialysis fluid inlet 54 Dialysis fluid outlet 56 Dialyzer inlet 58 Dialyzer outlet 60 Control unit 62 Connector / Adapter 64 Air separator 66 Fluid level sensor

Claims

1. An extracorporeal blood treatment device (2) for use in a blood treatment therapy, comprising: an extracorporeal circuit (4); a dialysis liquid circuit (8); and a dialyzer (6) comprising a blood side (9) fluidically connected to the extracorporeal circuit (4) and a dialysis liquid side (11) fluidically connected to the dialysis liquid circuit (8), wherein the blood side (9) of the dialyzer (6) and the dialysis liquid side (11) of the dialyzer (6) are separated from each other via a membrane (10) provided in the dialyzer (6), and the extracorporeal blood treatment device (2) further comprises a control unit (60) configured to automatically empty the dialyzer (6) after an end of the blood treatment therapy by setting a negative pressure in the dialysis liquid circuit (8) and a concomitant transfer of liquid from the blood side (9) via the membrane (10) of the dialyzer (6) into the dialysis liquid side (11), characterized in that the control unit (60) is configured, when the liquid from the extracorporeal circuit (4) has completely transferred from the blood side (9) via the membrane (10) of the dialyzer (6) into the dialysis liquid side (11) and the blood side (9) of the dialyzer (6) has been emptied, to cause, by a continued setting of the negative pressure in the dialysis liquid circuit (8), a transfer of air from the blood side (9) via the membrane (10) of the dialyzer (6) to the dialysis liquid side (11) and a displacement of the liquid out of the dialysis liquid side (11) of the dialyzer (6) to a dialysis liquid outflow (54), in order to also automatically empty the dialysis liquid side (11) of the dialyzer (6).

2. The extracorporeal blood treatment device (2) according to claim 1, characterized in that the dialyzer (6) is arranged or oriented during automatic emptying thereof on the extracorporeal blood treatment device (2) such that a dialysis liquid exit (58) connected to the dialysis liquid outflow (54) is arranged below a dialysis liquid inlet (56) connected to a dialysis liquid inflow (52).

3. The extracorporeal blood treatment device (2) according to claim 1 or 2, characterized in that the control unit (60) is configured to generate the negative pressure in the dialysis liquid circuit (8) such that a flux-pump outlet (48), which is a fluid pump in the dialysis liquid outflow (54) of the dialysis liquid circuit (8), is driven to pump the liquid or air out of the dialyzer (6) into the dialysis liquid outflow (54).

4. The extracorporeal blood treatment device (2) according to one of the preceding claims, characterized in that the control unit (60) is configured to drive or actuate a compressor pump (34) provided in the extracorporeal circuit (4) to support the transfer of the liquid or air from the blood side (9) via the membrane (10) of the dialyzer (6) to the dialysis liquid side (11).

5. The extracorporeal blood treatment device (2) according to one of the preceding claims, characterized in that the control unit (60) is configured to control or regulate a transmembrane pressure of the dialyzer (6) during automatic emptying of the dialyzer (6) to a pressure that is greater than a predetermined value and smaller than a dialyzer-specific, maximum permissible transmembrane pressure.

6. The extracorporeal blood treatment device (2) according to claim 5, characterized in that the control unit (60) is configured to control or regulate the transmembrane pressure of the dialyzer (6) to a pressure greater than 400 mmHg, preferably greater than 500 mmHg.

7. The extracorporeal blood treatment device (2) according to one of the preceding claims, characterized in that the control unit (60) is configured to stop the automatic emptying of the dialysis liquid side (11) of the dialyzer (6) in a sensor-controlled manner.

8. The extracorporeal blood treatment device (2) according to claim 7, characterized in that the control unit (60) is configured to evaluate a pressure signal or pressure course of a pressure sensor (50) arranged in the dialysis liquid outflow (54), which measures or monitors a pressure in the dialysis liquid outflow (54), and to stop the automatic emptying of the dialysis liquid side (11) based on the pressure signal or pressure course of the pressure sensor (50).

9. The extracorporeal blood treatment device (2) according to claim 8, characterized in that the control unit (60) is configured to evaluate a slope or a first derivative of the pressure signal or of the pressure course of the pressure sensor (50), and to stop the automatic emptying of the dialysis liquid side (11) if the slope or first derivative of the pressure signal or the pressure course falls below a predetermined first limit value.

10. The extracorporeal blood treatment device (2) according to claim 7, characterized in that the control unit (60) is configured to stop the automatic emptying of the dialysis liquid side (11) in a sensor-controlled manner if an air separator (64) provided or arranged in the dialysis liquid circuit (8) detects or measures that a liquid level of the air separator (64) has fallen below a predetermined liquid level or gauge height.

11. The extracorporeal blood treatment device (2) according to one of the preceding claims, characterized in that the control unit (60) is configured to stop the automatic emptying of the dialysis liquid side (11) of the dialyzer (6) in a time-controlled manner.

12. A method for automatically emptying a dialyzer (6) after an end of a blood treatment therapy, in particular performed or to be performed in an extracorporeal blood treatment device (2) according to one of the preceding claims, comprising the steps of: setting a negative pressure in a dialysis liquid circuit (8) and concomitant transfer of a liquid from a blood side (9) of the dialyzer (6) via a membrane (10) of the dialyzer (6) into a dialysis liquid side (11) of the dialyzer (6), and when the liquid from an extracorporeal circuit (4) has completely passed from the blood side (9) via the membrane (10) of the dialyzer (6) into the dialysis liquid side (11) and the blood side (9) of the dialyzer (6) has been emptied, continuing to set the negative pressure in the dialysis liquid circuit (8) to cause a transfer of air from the blood side (9) via the membrane (10) of the dialyzer (6) to the dialysis liquid side (11) and a displacement of liquid out of the dialysis liquid side (11) of the dialyzer (6) to a dialysis liquid outflow (54) in order to also automatically empty the dialysis liquid side (11) of the dialyzer (6).