Automatic emptying of the dialyzer after blood processing treatment

Abstract

This disclosure relates to an extracorporeal blood treatment device, comprising: an extracorporeal circuit; a dialysate circuit; and a dialyzer including a blood side and a dialysate side, wherein the blood side and the dialysate side are separated from each other by a membrane. The blood treatment device includes a control unit configured to automatically empty the dialyzer and transfer fluid from the blood side to the dialysate side via the membrane of the dialyzer by setting a negative or low pressure in the dialysate circuit. The control unit is configured to, when fluid from the extracorporeal circuit has been completely transferred from the blood side to the dialysate side via the membrane and the blood side of the dialyzer is emptied, continue to set a negative or low pressure in the dialysate circuit to cause air to transfer from the blood side to the dialysate side via the membrane and cause fluid to be expelled from the dialysate side to a dialysate drain port.

Description

Technical Field

[0001] This disclosure relates to an extracorporeal blood treatment device, particularly a dialysis machine, used in blood treatment therapy, comprising: an extracorporeal circuit; a dialysate circuit; and a dialyzer including a blood side fluidly connected to the extracorporeal circuit and a dialysate side fluidly connected to the dialysate circuit, wherein the blood side and the dialysate side of the dialyzer are separated from each other by a membrane disposed in the dialyzer, and the extracorporeal blood treatment device further includes a control unit configured to automatically empty the dialyzer after the blood treatment is completed by setting a negative or low pressure in the dialysate circuit, and fluid is transferred from the blood side to the dialysate side via the membrane of the dialyzer. Furthermore, this disclosure relates to a method for automatically emptying the dialyzer after the blood treatment is completed. Background Technology

[0002] Following blood treatment, in which the patient's blood is cleaned externally using a dialyzer and, if necessary, dialysate flowing through the dialyzer, the blood still in the extracorporeal circuit, such as in an arterial / venous tubing system (A / V tubing system), is in principle reinfused into the patient. This process is called reinfusion. The patient is only completely decoupled from the extracorporeal tubing system (arterial and venous) when the blood still present in the extracorporeal circuit is appropriately reinfused / reinfused into the patient. After reinfusion, there is essentially still (reinfused) fluid in the extracorporeal circuit, dialyzer, etc. The tubing and dialyzer that form the extracorporeal and dialysate circuits should be emptied / drained before disposal, especially to reduce (weight-related) disposal costs.

[0003] Existing technology

[0004] In the prior art, extracorporeal blood processing devices are known, which require multiple steps to be manually performed by the user when emptying the dialyzer after blood processing treatment and after re-infusion of the patient's blood. For example, it is known that the extracorporeal circuit or blood tubing system is first decoupled from the dialyzer and emptied into the bag or waste port of the blood processing device. Subsequently, the dialysate inflow tubing, which is decoupled from the dialyzer, and the fluid still present in the dialyzer is at least partially aspirated through the dialysate outflow tubing.

[0005] This partially automated emptying process requires several manually performed steps in an unfavorable manner. Caregivers must interact with the extracorporeal blood processing device multiple times, resulting in significant waiting time at the machine. Furthermore, while this emptying method appropriately removes any remaining fluid from the dialysate side of the dialyzer, this is not the case for the blood side. Consequently, the dialyzer remains very heavy after emptying, leading to high disposal costs.

[0006] Automated purging of the extracorporeal circuit / A / V tubing system and the blood side of the dialyzer is known from EP 3 231 466 B1. Here, a low pressure is generated on the dialysate side of the dialyzer, and fluid is drawn from the blood side of the dialyzer by means of this low pressure, causing the fluid to transfer from the blood side to the dialysate side via the dialyzer membrane. This fluid transfer is supported by a level / or grading pump located in the extracorporeal circuit. During the purging process, the ends of the arterial and venous sections of the extracorporeal circuit are shorted, and at least one blood pump located in the extracorporeal circuit is in operation, causing the fluid present in the shorted blood circuit to be delivered along the therapeutic flow direction to the blood side of the dialyzer, where it is transferred to the dialysate side of the dialyzer by a pressure drop and then drawn out.

[0007] EP 3 231 466 B1 does not address the draining of the dialysate side of the dialyzer. In this context, it is assumed that even after draining the blood side and extracorporeal circuit of the dialyzer as described in EP 3 231 466 B1, several manual steps are required (decoupling the extracorporeal circuit from the dialyzer, decoupling the dialysate inlet tubing from the dialyzer, and aspirating the remaining fluid from the dialyzer through the dialysate outlet tubing). Therefore, although the weight of the dialyzer after draining can be reduced using the disclosure of EP 3231 466 B1, several manual steps are still required from the user.

[0008] Finally, fully automated purging of the dialyzer after blood treatment is known from EP 1 996 253 B1. According to EP 1 996 253 B1, the blood side and extracorporeal circuit of the dialyzer are first purged in a manner similar to EP 3 231 466 B1. Subsequently, the dialysate side of the dialyzer is also automatically purged. For this purpose, the (venting) valve in the dialysate inlet is opened. When the fluid pump in the dialysate vent is operated at this time, air can flow into the dialyzer (supported by a compressor in the dialysate inlet if necessary), causing the liquid still on the dialysate side of the dialyzer to flow towards the dialyzer outlet until the entire dialyzer is filled with air.

[0009] In EP 1 996 253 B1, an additional venting valve is required to enable fully automatic venting of the dialyzer.

[0010] Not only EP 1 996 253 B1, but also EP 3 231 466 B1 discloses an extracorporeal blood processing device. Summary of the Invention

[0011] In this context, the objective of this disclosure is to avoid or at least mitigate the disadvantages of the prior art. In particular, the dialyzer should be emptied completely automatically after blood processing treatment to minimize the disposal weight of the dialyzer. Furthermore, interaction between caregivers and the extracorporeal blood processing device should be reduced. Moreover, for automatic emptying, it is preferable to use / require only components already standardly present in the extracorporeal blood processing device.

[0012] This task is accomplished by the extracorporeal blood processing device according to the invention and the method according to the invention for automatically emptying the dialyzer after blood processing treatment. Advantageous improvements and embodiments are described below.

[0013] This disclosure first relates to an extracorporeal blood treatment device for use in blood treatment therapy, comprising: an extracorporeal circuit; a dialysate circuit; and a dialyzer including a blood side fluidly connected to the extracorporeal circuit and a dialysate side fluidly connected to the dialysate circuit, wherein the blood side and the dialysate side of the dialyzer are separated from each other by a membrane disposed in the dialyzer, and the extracorporeal blood treatment device further includes a control unit configured to automatically empty the dialyzer after the blood treatment therapy is completed by setting a negative pressure or a low pressure in the dialysate circuit, and fluid is transferred from the blood side to the dialysate side via the membrane of the dialyzer. The control unit is configured to, when the fluid from the extracorporeal circuit has been completely transferred from the blood side to the dialysate side via the membrane and the blood side of the dialyzer is emptied, cause air to transfer from the blood side to the dialysate side via the membrane of the dialyzer and cause the fluid to be expelled from the dialysate side of the dialyzer to the dialysate drain (downstream of the dialyzer) by continuing to set a negative or low pressure in the dialysate circuit, so as to automatically empty the dialysate side of the dialyzer as well.

[0014] According to this disclosure, the control unit preferably controls the reinfusion of blood to the patient after the blood treatment is completed, such that the (dialysis) fluid from the dialysate circuit is provided to the extracorporeal circuit via the membrane of the dialyzer, which, during reinfusion, displaces the blood present in the extracorporeal circuit toward the patient so as to return the blood to the patient not only through the venous segment but also through the arterial segment.

[0015] Preferably, the control unit is configured to close the arterial hose clamp in the arterial segment of the extracorporeal circuit and the venous hose clamp in the venous segment of the extracorporeal circuit when re-infusion (not only via the arterial segment of the extracorporeal circuit but also via the venous segment of the extracorporeal circuit) has been interrupted.

[0016] In a favorable manner, the patient was subsequently decoupled by the caregiver not only arterially but also venously.

[0017] After patient decoupling, the connector at the end / patient side of the preferred arterial segment is shorted or interconnected with the connector at the end / patient side of the preferred venous segment. This advantageously represents the last active interaction between the caregiver and the extracorporeal blood processing device. In other words, as specified in this disclosure, a fully automated, controllable emptying of the dialyzer is subsequently performed without the caregiver needing to interact with the extracorporeal blood processing device again.

[0018] Furthermore, it is preferable that the dialyzer is arranged or oriented on the extracorporeal blood processing device in such a way that the dialysate outlet (in the height / vertical / height direction of the extracorporeal blood processing device) connected to the dialysate drain is positioned below the dialysate inlet connected to the dialysate inlet.

[0019] In other words, the dialyzer is preferably arranged / oriented on the extracorporeal blood processing device in such a way that the dialysate outlet is below and the dialysate inlet is above during its automatic emptying. Here, the dialyzer is particularly preferably vertically oriented, that is, the longitudinal axis of the basically cylindrical dialyzer preferably extends in the vertical direction (perpendicular to the Earth's surface).

[0020] If the dialyzer outlet is positioned at the top and not at the bottom during blood processing (e.g., due to the principle of backflow) in the basic setup of the extracorporeal blood processing device, then the caregiver needs to rotate the dialyzer before automatic emptying, that is, orient it so that the dialysate outlet is at the bottom. This manual step, which is necessary when required, can be performed by the caregiver along with the shorting of the extracorporeal circuit, thus preferably eliminating the need for additional interactions related to caregiver waiting time.

[0021] Immediately following patient decoupling and possible dialyzer rotation, the blood side of the dialyzer is first emptied in an advantageous manner. In particular, the method described in EP 3 231 466 B1 can be performed here, which provides a suitable method for emptying the blood tubing system and the blood side of the dialyzer / dialyzer. Therefore, the control unit is specifically configured to build / generate a negative pressure or low pressure in the dialysate circuit (on the dialysate side), thereby aspirating the (dialysis) fluid present in the extracorporeal circuit (on the blood side). Here, the fluid (still present in the extracorporeal circuit) is preferably supplied from the extracorporeal circuit via the dialyzer membrane to the dialysate circuit during emptying, more specifically, for an extended period until no fluid remains in the extracorporeal circuit and on the blood side of the dialyzer.

[0022] The core of this disclosure is that the control unit is configured to control the evacuation of the dialyzer in such a way that first, liquid and then (when the liquid from the extracorporeal circuit has completely passed through the dialyzer membrane from the blood side to the dialysate side, that is, when there is no more liquid in the extracorporeal circuit and the blood side of the dialyzer) air are transferred from the extracorporeal circuit / blood side through the dialyzer membrane to the dialysate circuit / dialysate side, so that the dialysate is also expelled from the dialysate side of the dialyzer toward the dialysate drain port by the transferred air.

[0023] In particular, as demonstrated by this disclosure, when the fluid from the extracorporeal circuit has been completely transferred from the blood side to the dialysate side via the dialyzer membrane and the blood side of the dialyzer is emptied, air can be slowly transferred from the blood side to the dialysate side via the dialysate membrane by continuing to set the negative or low pressure (suction pressure on the dialysate side) in the dialysate circuit. If the dialyzer is now oriented such that the dialyzer outlet or dialysate drain is below and the dialyzer inlet or dialysate inlet is above, then the transferred air is collected in the upper section of the dialyzer (near the dialyzer inlet), displacing the fluid downward toward the dialyzer outlet and forcing the fluid remaining on the dialysate side out of the dialyzer through the dialyzer outlet.

[0024] Therefore, the control unit is generally configured to empty the dialyzer completely automatically after the blood treatment is completed.

[0025] Preferably, the control unit is configured to generate a negative or low pressure in the dialysate circuit, such that the outlet of the flow pump is controlled. This flow pump is a fluid pump in the dialysate drain port (downstream of the dialyzer) of the dialysate circuit to pump liquid or air (from the blood side through the dialyzer membrane into the dialysate side and ultimately) from / out of the dialyzer into the dialysate drain port.

[0026] Advantageously, the control unit is configured to operate / manipulate a compressor pump located in the extracorporeal circuit such that the compressor pump supports the transfer of liquid and / or air from the blood side via the dialyzer membrane to the dialysate side. In particular, the control unit is configured to operate the compressor pump such that the compressor pump pushes liquid and air through the dialyzer membrane.

[0027] Advantageously, the control unit is also configured to control or regulate the transmembrane pressure of the dialyzer to a pressure greater than a predetermined value but less than the dialyzer-specific maximum permissible transmembrane pressure during automatic purging of the dialyzer. The maximum permissible transmembrane pressure depends particularly on the dialyzer type / dialyzer used and is generally given along with the dialyzer's datasheet.

[0028] Preferably, the control unit is configured to control or adjust the transmembrane pressure of the dialyzer to a pressure greater than 400 mmHg, preferably greater than 500 mmHg. For example, the transmembrane pressure may be controlled / adjusted by the control unit to a pressure between 500 mmHg and 600 mmHg, such as 550 mmHg, but only if the maximum permissible transmembrane pressure is not exceeded at the set pressure. Absolute care must be taken to ensure that the maximum permissible transmembrane pressure is not exceeded. Preferably, in the extracorporeal blood processing apparatus of this disclosure, only a dialyzer with a maximum permissible transmembrane pressure of at least 600 mmHg may be used.

[0029] As has been demonstrated in particular by this disclosure, when the low pressure on the dialysate side (by controlling the flow pump outlet) is generated together with the overpressure on the blood side (by controlling the compressor pump) to create a constant and high transmembrane pressure within the aforementioned range, air (relatively slowly) passes through the dialyzer membrane in the already emptied or purged extracorporeal circuit, and the dialysate still present on the dialysate side of the dialyzer is also expelled from the dialyzer.

[0030] Preferably, the control unit is configured to interrupt the automatic emptying of the dialysate side of the dialyzer in a sensor-controlled / regulated manner.

[0031] According to a preferred embodiment, the control unit is configured to evaluate the pressure signal or pressure change curve of a pressure sensor arranged in the dialysate drain port, the pressure sensor measuring or monitoring the pressure in the dialysate drain port, and to interrupt the automatic draining of the dialysate side based on the pressure signal or pressure change curve of the pressure sensor.

[0032] Here, the control unit is preferably configured to evaluate the pressure signal or the slope or first derivative of the pressure change curve from the pressure sensor, and to interrupt the automatic purging of the dialysate side when the pressure signal or the slope or first derivative of the pressure change curve falls below a predetermined first limit value. In particular, according to this disclosure, it has been found that when the pressure signal or the slope / first derivative of the pressure change curve from the pressure sensor becomes negative, air is present in the dialysate drain port.

[0033] According to an alternative preferred embodiment, the control unit can also be configured to, in a sensor-controlled manner, interrupt the automatic evacuation of the dialysate side when the air separator, which is installed or arranged in the dialysate circuit, detects or measures that the liquid level of the air separator has dropped to below a predetermined liquid level or horizontal height.

[0034] Alternatively or additionally, the control unit can also be configured to interrupt the automatic emptying of the dialysate side of the dialyzer in a time-controlled / regulated manner. In particular, a control that combines sensor-controlled interruption with time-controlled interruption is also conceivable.

[0035] Furthermore, this disclosure relates to a method for automatically emptying a dialyzer after a blood treatment is completed, particularly performed or to be performed in an extracorporeal blood treatment device as described above, the method comprising the steps of: setting a negative or low pressure in the dialysate circuit and simultaneously transferring fluid from the blood side of the dialyzer via the dialyzer membrane to the dialysate side of the dialyzer; and when the fluid from the extracorporeal circuit has been completely transferred from the blood side to the dialysate side via the dialyzer membrane and the blood side of the dialyzer is emptied, continuing to set a negative or low pressure in the dialysate circuit to cause air to transfer from the blood side to the dialysate side via the dialyzer membrane and the fluid to be expelled from the dialysate side of the dialyzer to the dialysate drain port, so as to also automatically empty the dialysate side of the dialyzer.

[0036] Preferably, the method further comprises the following steps: during automatic emptying of the dialyzer, the dialyzer is arranged or oriented on the extracorporeal blood processing device such that the dialysate outlet (in the height direction / vertical direction / height direction of the extracorporeal blood processing device) connected to the dialysate drain port is arranged below the dialysate inlet connected to the dialysate inlet.

[0037] Advantageously, the method further includes the step of generating negative or low pressure in the dialysate circuit by pumping liquid or air from the dialyzer into the dialysate drain section by means of a flow pump outlet, said flow pump being a fluid pump in the dialysate drain port of the dialysate circuit.

[0038] Preferably, the method further comprises the step of: supporting the transfer of liquid or air from the blood side through the dialyzer membrane to the dialysate side by means of a compressor pump disposed in the extracorporeal circuit.

[0039] In particular, the method further includes the step of controlling or adjusting the transmembrane pressure of the dialyzer to a pressure greater than a predetermined value and less than the maximum permissible transmembrane pressure specific to the dialyzer. Preferably, the method additionally includes the step of controlling or adjusting the transmembrane pressure of the dialyzer to a pressure greater than 400 mmHg, preferably greater than 500 mmHg.

[0040] Advantageously, the method further includes the step of: sensor-controlled interruption of automatic evacuation of the dialysate side of the dialyzer.

[0041] Preferably, the method further includes the following steps: evaluating the pressure signal or pressure change curve of a pressure sensor arranged in the dialysate drain port, the pressure sensor measuring or monitoring the pressure in the dialysate drain port, and interrupting the automatic draining of the dialysate side based on the pressure signal or pressure change curve of the pressure sensor.

[0042] More preferably, the method includes the steps of: evaluating the slope or first derivative of the pressure signal or pressure change curve of the pressure sensor, and interrupting the automatic draining of the dialysate side when the slope or first derivative of the pressure signal or pressure change curve is lower than a predetermined first limit value.

[0043] Alternatively, the method preferably includes the step of: when the air level of the air separator, which is set or arranged in the dialysate circuit, is detected or measured by the sensor, the automatic evacuation of the dialysate side is interrupted.

[0044] Alternatively or additionally, the method preferably includes the following steps: time-controlled interruption of automatic evacuation of the dialysate side of the dialyzer.

[0045] When performing the method according to this disclosure, it is preferable to connect the end of the arterial segment of the extracorporeal circuit to the end of the venous segment of the extracorporeal circuit, thereby decoupling the patient. Therefore, the method according to this disclosure does not relate to any method for performing surgical or therapeutic procedures on a human body. Attached Figure Description

[0046] The present disclosure is further illustrated below with reference to the accompanying drawings. It shows:

[0047] Figure 1 An extracorporeal blood processing device according to this disclosure is shown during blood processing therapy and / or during reinfusion;

[0048] Figure 2 An extracorporeal blood processing apparatus according to the present disclosure is shown during automatic emptying of a dialyzer;

[0049] Figure 3A detailed view of the dialyzer is shown with the blood side of the dialyzer completely emptied.

[0050] Figure 4 A detailed view of the dialyzer is shown with the dialysate side of the dialyzer just emptied.

[0051] Figure 5 A graph is shown, which displays the pressure signal or pressure change curve over time from a pressure sensor arranged in the dialysate drain outlet.

[0052] Figure 6 A graph is shown, in which the first derivative of the pressure signal or pressure change curve of the pressure sensor with respect to time is displayed; and

[0053] Figure 7 The table shows the time required for different dialyzer evacuation methods and the remaining disposal weight.

[0054] Wherein: 2-Extracorporeal blood processing device / dialysis machine; 4-Extracorporeal circuit; 6-Dialyzer; 8-Dialysate circuit; 9-Blood side; 10-Membrane; 11-Dialysate side; 12-Arterial segment; 14-Venous segment; 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 Sensors; 32-Vein 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-Dialysate inlet; 54-Dialysate outlet; 56-Dialyzer inlet; 58-Dialyzer outlet; 60-Control unit; 62-Connector / adapter; 64-Air separator; 66-Level sensor. Detailed Implementation

[0055] The accompanying drawings are merely illustrative and intended only for understanding this disclosure. The same elements are given the same reference numerals. Features of the various embodiments may be interchanged with each other unless explicitly stated otherwise.

[0056] Figure 1 An extracorporeal blood treatment device (dialysis machine) 2 is shown during blood treatment or during reinfusion, i.e. before automatic emptying according to this disclosure.

[0057] The extracorporeal blood processing device 2 basically includes an extracorporeal circuit (A / V tubing system) 4, a dialyzer 6, and a dialysate circuit 8. The blood side 9 of the dialyzer 6 is separated from the dialysate side 11 of the dialyzer 6 via a (hollow fiber) membrane 10.

[0058] The extracorporeal circuit 4 includes an arterial segment 12 upstream of the dialyzer 6 and a venous segment 14 downstream of the dialyzer 6.

[0059] from Figure 1 It can be seen that arterial segment 12 and venous segment 14 are coupled to patient 15. In other words, the end of arterial segment 12 is coupled to the artery of patient 15, and the end of venous segment 14 is coupled to the vein of patient 15.

[0060] In the venous section 14 of the extracorporeal circuit 4, the venous expansion chamber or air trap 16, the venous safety air detector 18, and the venous tubing clamp 20 are located downstream of the dialyzer 6 (i.e., from the end of the dialyzer 6 toward the venous section 14).

[0061] In arterial segment 12, an arterial hose clamp 22, an arterial safety air detector 24, and an (arterial) blood pump 26 are provided from the patient-side end of arterial segment 12 in the direction toward dialyzer 6. (As in...) Figure 1 As can be seen, the extracorporeal circuit 4 (especially its blood pump adapter) has been installed in the blood pump 26, which is preferably constructed as a roller pump or a peristaltic pump and is configured to deliver fluid / liquid by squeezing a tubing.

[0062] In the arterial segment 12, arterial pressure can be measured upstream or in front of the blood pump 26 using the arterial pressure sensor 28. Furthermore, dialyzer inlet pressure can be measured downstream and / or posterior to the blood pump 26 and upstream and / or in front of the dialyzer 6 (between the dialyzer 6 and the blood pump 26) using the dialyzer inlet pressure sensor 30. In the venous segment 14, venous pressure at or behind the venous expansion chamber or air trap 16 can be measured via the venous pressure sensor 32. Pressure sensors 28, 30, and 32, located in the extracorporeal circuit 4, can measure / collect / monitor pressure at corresponding locations within the extracorporeal circuit 4.

[0063] from Figure 1 It can also be seen that the compressor pump or level or level regulating pump (LRP) 34 is downstream of the arterial pressure sensor 28, the dialyzer inlet pressure sensor 30 and the venous pressure sensor 32. The level or level regulating pump has associated valves 36, 38 and 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.

[0064] The dialysate circuit 8 includes 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 the dialysate 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 the dialysate outlet 54 downstream of the dialyzer 6. Preferably, the flow pump inlet 46 and the flow pump outlet 48 are gear pumps. The dialysate inlet 52 is coupled to the dialyzer inlet 56 of the dialyzer 6. The dialysate outlet 54 is coupled to the dialyzer outlet 58 of the dialyzer 6.

[0065] Furthermore, the extracorporeal blood processing device 2 has a control unit 60, which is preferably configured as a processor, particularly as a central computing or processing unit (CPU). The control unit 60 is preferably integrated into the extracorporeal blood processing device 2, i.e., not separated from it. The control unit 60 obtains information from sensors disposed within the extracorporeal blood processing device 2. Here, only illustrative examples are mentioned. Figure 1 The sensors shown include arterial pressure sensor 28, dialyzer inlet pressure sensor 30, venous pressure sensor 32, arterial safety air detector 24, venous safety air detector 18, and pressure sensor 50. On the other hand, the control unit 60 controls or manipulates the actuators disposed in the extracorporeal blood processing device 2. This is merely an example; the sensors shown here are... Figure 1 The valves, pumps, hose clamps, etc. shown are all worth mentioning, namely, dialyzer inlet valve 42, dialyzer outlet valve 44, flow pump inlet 46, flow pump outlet 48, (arterial) blood pump 26, arterial hose clamp 22, venous hose clamp 20, etc.

[0066] After the blood treatment is completed, the control unit 60 first controls the re-infusion of blood to the patient 15, such that the (dialysis) fluid from the dialysate circuit 8 is supplied to the extracorporeal circuit 4 via the membrane 10 of the dialyzer 6, which, during the re-infusion, displaces the blood still present in the extracorporeal circuit 4 towards the patient 15, so that the blood is returned to the patient 15 via the venous segment 14 and via the arterial segment 12. Here, an overpressure is advantageously established on the dialysate side 11 to force the fluid through the membrane 10 of the dialyzer 6 into the blood side 9. Additionally, a low pressure can be established on the blood side 9 so that fluid is also drawn into the blood side 9 via the membrane 10 of the dialyzer 6.

[0067] In order to interrupt reinfusion not only via the arterial segment 12 of the extracorporeal circuit 4 but also via the venous segment 14 of the extracorporeal circuit 4 (when blood has been completely reinfused), the control unit 46 closes the arterial hose clamp 22 and the venous hose clamp 20. The patient 15 is then decoupled by caregivers not only arterially but also venously.

[0068] Figure 2 The extracorporeal blood processing device (dialysis machine) 2 is shown during the automatic emptying of dialyzer 6. It can be seen that after decoupling from patient 15, arterial segment 12 and venous segment 14 are shorted or fluidly connected to each other, for example, via connector / adapter 62. Dialyzer 6 (in order to achieve its automatic emptying) is rotated by a caregiver, such that during… Figure 2 The dialyzer outlet 58 is located at the bottom and the dialyzer inlet 56 is located at the top. The dialyzer 6 is oriented vertically in an advantageous manner when the dialyzer is automatically emptied.

[0069] Reference Figure 2 The automatic emptying control of the dialyzer 6, executed by the control unit 60, will be described.

[0070] Preferably, the control unit 60 is configured to first generate or establish a low pressure on the dialysate side 11 of the dialyzer 6. For this purpose, the control unit 60 controls the flow pump outlet 48 to pump the fluid present in the extracorporeal circuit 4 and the blood side 9 of the dialyzer 6 to the dialysate side 11 of the dialyzer 6 and pump it out of the dialyzer 6 to the dialysate drain port 54. Here, it is preferable to stop the flow pump inlet 46, close the dialyzer inlet valve 42, and open the dialyzer outlet valve 44.

[0071] Furthermore, the control unit 60 can operate the compressor pump 34 so that the compressor pump supports the transfer of fluid from the blood side 9 through the membrane 10 of the dialyzer 6 toward the dialysate side 11. For this purpose, the compressor pump 34 preferably pressurizes 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 (the air supply is controlled / regulated via the venous pressure sensor 32). By introducing air into the extracorporeal circuit 4, pressure is established in the extracorporeal circuit 4, and the fluid still present in the extracorporeal circuit 4 is additionally pressurized from the blood side 9 into the dialysate side 11 via the membrane 10 of the dialyzer 6.

[0072] According to this disclosure, the operation of the compressor pump 34 during the automatic evacuation of the dialyzer 6 is optional, i.e., not absolutely necessary.

[0073] However, under any circumstances, 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 particularly confirmed that this transmembrane pressure should be greater than 400 mmHg, especially greater than 500 mmHg, for example, 550 mmHg. The transmembrane pressure can be controlled / regulated by the control unit 60 solely by manipulating the flow pump outlet 48 (e.g., changing its delivery rate). In other words, in principle, only a suitable low pressure can be generated on the dialysate side 11. Alternatively, overpressure can also be generated on the blood side 9 by additionally manipulating the compressor pump 34.

[0074] In any case, the transmembrane pressure is controlled or regulated by the control unit 60 in such a way that it does not exceed the maximum permissible transmembrane pressure of the dialyzer 6 used, which is known, for example, to the user before blood treatment and is therefore known for the blood treatment apparatus 2, and especially for the control unit 60 of the blood treatment apparatus. This in particular prevents the hollow fibers of the membrane 10 from tearing, and thus, if necessary, allows blood particles still present in the liquid to be transferred to the dialysate side 11.

[0075] If the fluid from the extracorporeal circuit 4 is completely transferred from the blood side 9 to the dialysate side 11 via the membrane 10 of the dialyzer 6 and the blood side 9 of the dialyzer 6 is emptied, then according to this disclosure, the low pressure already present on the dialysate side 11, or in particular the controlled / regulated transmembrane pressure, is maintained. Specifically, according to this disclosure, it has been found that when the transmembrane pressure is controlled / regulated to such a high value, not only fluid but also air can be transported through the membrane 10 of the dialyzer 6. At least at this point, the dialyzer outlet 58 must be pointing downwards. Due to the present low pressure and the emptied extracorporeal circuit 4, air now displaces the membrane 10 of the dialyzer 6 and also displaces the fluid still present in the dialyzer 6 from the dialysate side 11 to the dialysate drain port 54. Air transfer is preferably also supported by a compressor pump 34.

[0076] Figure 3 A detailed view of dialyzer 6 is shown with the blood side 9 of the dialyzer completely emptied. Figure 4 A detailed view of the dialyzer 6 is shown with the dialysate side 11 of the dialyzer just emptied. (See especially from...) Figure 4 As can be seen, the transferred air first accumulates in the upper section of dialyzer 6 (in the region of dialyzer inlet 56 / near the dialyzer inlet) and pushes the liquid downward toward dialyzer outlet 58.

[0077] The control unit 60 is preferably configured to interrupt the automatic evacuation of the dialyzer 6 when the dialysate side 11 of the dialyzer 6 is also completely emptied. The preferred interruption criteria of this disclosure will first refer to... Figure 3 and Figure 4 Describe it.

[0078] In principle, it is conceivable, according to this disclosure, to interrupt automatic purging in a time-controlled manner. For example, the control unit 60 may identify when the blood side 9 of the dialyzer 6 has been completely purged based on the sensor data it transmits. If the control unit 60 knows how long the dialysate side 11 of the dialyzer 6 typically requires to be purged at a set transmembrane pressure, the control unit 60 may interrupt automatic purging when the corresponding time period has elapsed.

[0079] According to this disclosure, a particularly preferred feature is the sensor-controlled interruption of the automatic emptying of the dialysate side 11 of the dialyzer 6. Here, the control unit 60 advantageously evaluates the pressure signal or pressure change curve of the pressure sensor 50 arranged in the dialysate drain port 54.

[0080] Alternatively, automatic purging can be interrupted by sensor control via an air separator 64 located in the dialysate circuit 8, particularly in the dialysate drain port 54. The air separator 64 is, in principle, used to remove air from the dialysate and protect the flow pump outlet 48 from unwanted air ingress during blood treatment. At least one level sensor 66 is provided in the air separator 64. If the level sensor 66 detects that the level in the air separator 64 has dropped below a predetermined level or height, this means that air has entered the air separator 64 via the dialysate drain port 54, and therefore the dialysate side 11 of the dialyzer 6 is also emptied.

[0081] Because a relatively long hose section (approximately 1 meter) exists between the dialyzer 6 and the air separator 64 in practice, when the air separator 64 is interrupted for sensor control, the interruption lasts for a very long time until automatic purging is interrupted. In this context, considering the interruption of sensor control according to this disclosure, a pressure sensor (PDA) 50 is preferred in principle. This is because the duration of pressure change transmission through the hose section is significantly shorter than the duration of air entering the air separator 64 via the dialysate drain port 54. Even Figure 3 and Figure 4 Both views are basic schematic diagrams, but it should be clear in both figures that the pressure sensor 50 and the air separator 64 are arranged away from the dialyzer 6. According to this disclosure, the air separator 64 and the pressure sensor 50 can also be combined in a single component, as in... Figure 3 and Figure 4 As shown in the image.

[0082] Also refer to Figure 5 and Figure 6 To more accurately describe the interruption of the sensor-controlled automatic emptying of the dialysate side 11 of dialyzer 6, here, Figure 5 A graph is shown that illustrates the change of the pressure signal or pressure change curve of the pressure sensor 50 over time. Figure 6 A graph is shown that displays the slope / first derivative / gradient of the pressure signal or pressure change curve of the pressure sensor 50 with respect to time.

[0083] The control unit 60 is preferably located at the end of the evacuation process, i.e., for example at... Figure 5 or Figure 6The pressure is monitored from approximately 200 seconds onwards by the pressure sensor (PDA) 50. When the dialyzer 6 is completely emptied, air is transferred into the dialysate drain port 54. This is accompanied by a pressure drop in the dialysate drain port 54, which is measured by the pressure sensor (PDA) 50. Figure 5 and Figure 6 It was learned that the pressure measured by pressure sensor 50 remained almost constant during venting. The same applied to the slope of the pressure signal. After approximately 1200 seconds, Figure 5 The signal in the pressure sensor 50 begins to fluctuate. This is an indication that air is now (also) present on the pressure sensor 50. The slope of the pressure signal also changes (see...). Figure 6 According to this disclosure, it has been found that the interruption of automatic purging of the dialyzer 6 is optimally achieved by means of the slope or first derivative of the pressure signal. When the slope is below a predetermined negative value x, preferably set between -3 and -5, and more preferably set to (approximately) -4, the interruption criterion is met. This is in Figure 6 This is the case at time point t1.

[0084] at last, Figure 7 A table is shown, which provides the time required for purging different dialyzers and the remaining disposal weight. The same dialyzer (“Xevonta Hi23”) was used for all experiments.

[0085] In experiments using the “S1” characterization method, the extracorporeal circuit or blood tubing system was first decoupled from the dialyzer and emptied into the bag or waste port of the blood processing device. Subsequently, the dialysate inlet was decoupled from the dialyzer, and at least partially of the remaining fluid in the dialyzer was aspirated through the dialysate outlet. This evacuation method was found to last only 43 seconds. The processed weight was 543.8 grams.

[0086] In the test indicated by "S2", the dialyzer was emptied as in the prior art of EP 1 996 253 B1, i.e., via a valve located in the dialysate inlet. This emptying method was found to last 154 seconds. The disposal weight was 381.1 grams.

[0087] In the test indicated by "S3", the dialyzer was emptied according to this disclosure, wherein the automatic emptying of the dialyzer was interrupted by a sensor-controlled interruption via a pressure sensor in the dialysate drain port. It was found that this emptying method lasted 493 seconds. The disposal weight could be reduced to 359.2 grams.

[0088] In the test indicated by "S4", the dialyzer was emptied according to this disclosure, wherein the automatic emptying of the dialyzer was interrupted by a sensor-controlled interruption via an air separator in the dialysate drain port. It was found that this emptying method lasted 573 seconds. The disposal weight could be reduced to 357.9 grams.

[0089] Therefore, it has been found that, according to this disclosure (see experiments “S3” and “S4”), treatment weight can be reduced compared to the prior art (particularly regarding experiment “S1”, but also regarding experiment “S2”). Although the dialyzer emptying according to this disclosure takes a relatively long time, this disadvantage is acceptable in the context of achievable treatment cost savings. Furthermore, the longer duration does not play a significant role in practice. This is because dialyzer emptying is performed automatically (i.e., without nursing intervention) and is ultimately only used for the time after patient decoupling, especially until the patient leaves their treatment facility.

Claims

1. An extracorporeal blood treatment apparatus (2) for use in a blood treatment therapy, having: - an extracorporeal circuit (4); - a dialysate circuit (8); and - a dialyzer (6) comprising a blood side (9) and a dialysate side (11), the blood side being in fluid connection with the extracorporeal circuit (4), the dialysate side being in fluid connection with the dialysate circuit (8), wherein - the blood side (9) of the dialyzer (6) and the dialysate side (11) of the dialyzer (6) are separated from each other by a membrane (10) provided in the dialyzer (6), and - the extracorporeal blood treatment apparatus (2) further comprises a control unit (60) arranged to automatically empty the dialyzer (6) after the blood treatment therapy has ended by setting a negative pressure in the dialysate circuit (8) and liquid is at the same time transferred from the blood side (9) into the dialysate side (11) via the membrane (10) of the dialyzer (6), characterized in that - when the liquid from the extracorporeal circuit (4) has been completely transferred from the blood side (9) into the dialysate side (11) via the membrane (10) of the dialyzer (6) and the blood side (9) of the dialyzer (6) is empty, the control unit (60) is arranged to, by continuing to set the negative pressure in the dialysate circuit (8), cause air to be transferred from the blood side (9) into the dialysate side (11) via the membrane (10) of the dialyzer (6) and cause the liquid to be expelled from the dialysate side (11) of the dialyzer (6) to a dialysate drain (54) in order to also automatically empty the dialysate side (11) of the dialyzer (6), - the dialyzer is arranged or oriented on the extracorporeal blood treatment apparatus (2) such that a dialysate outlet (58) connected to the dialysate drain (54) is arranged below a dialysate inlet (56) connected to a dialysate inflow (52) when the dialyzer is automatically emptied, - the control unit (60) is arranged to generate a negative pressure in the dialysate circuit (8) such that a flow pump outlet (48) is actuated to pump liquid or air out of the dialyzer (6) into the dialysate drain (54), the flow pump being a fluid pump in the dialysate circuit (8) at the dialysate drain (54), and - the control unit (60) is arranged to actuate or manipulate a compressor pump (34) provided in the extracorporeal circuit (4) such that the compressor pump supports the transfer of air from the blood side (9) into the dialysate side (11) via the membrane (10) of the dialyzer (6).

2. The extracorporeal blood treatment apparatus (2) according to claim 1, characterized in that - the control unit (60) is arranged to actuate or manipulate a compressor pump (34) provided in the extracorporeal circuit (4) such that the compressor pump supports the transfer of liquid from the blood side (9) into the dialysate side (11) via the membrane (10) of the dialyzer (6).

3. An extracorporeal blood treatment apparatus (2) according to claim 1 or 2, 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 a predetermined value and less than a dialyzer-specific maximum allowable transmembrane pressure upon automatic emptying of the dialyzer (6).

4. The extracorporeal blood treatment apparatus (2) according to claim 3, 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.

5. An extracorporeal blood treatment apparatus (2) according to claim 1 or 2, characterized in that The control unit (60) is configured to sensorically interrupt the automatic emptying of the dialysate side (11) of the dialyzer (6).

6. An extracorporeal blood treatment apparatus (2) according to claim 5, characterized in that The control unit (60) is configured to evaluate a pressure signal or pressure profile of a pressure sensor (50) arranged in the dialysate drain (54), which pressure sensor measures or monitors the pressure in the dialysate drain (54), and to interrupt the automatic emptying of the dialysate side (11) based on the pressure signal or pressure profile of the pressure sensor (50).

7. An extracorporeal blood treatment device (2) according to claim 6, characterized in that The control unit (60) is configured to evaluate the slope or first derivative of the pressure signal or pressure profile of the pressure sensor (50) and to interrupt the automatic emptying of the dialysate side (11) when the slope or first derivative of the pressure signal or pressure profile is below a predetermined first limit value.

8. An extracorporeal blood treatment apparatus (2) according to claim 5, characterized in that The control unit (60) is configured to sensorically interrupt the automatic emptying of the dialysate side (11) when a drop in the liquid level of an air separator (64) arranged or disposed in the dialysate circuit (8) is detected or measured by the air separator (64) below a predetermined liquid level or level height.

9. An extracorporeal blood treatment apparatus (2) according to claim 1 or 2, characterized in that The control unit (60) is configured to time-controlled interrupt the automatic emptying of the dialysate side (11) of the dialyzer (6).

10. A method for automatically emptying a dialyzer (6) after the end of a blood treatment treatment, which method is performed or to be performed in an extracorporeal blood treatment apparatus (2) according to any one of the preceding claims 1 to 9, the method having the steps of: - setting a negative pressure in the dialysate circuit (8) and, in conjunction therewith, transferring liquid from the blood side (9) of the dialyzer (6) via the membrane (10) of the dialyzer (6) into the dialysate side (11) of the dialyzer (6), - when the liquid from the extracorporeal circuit (4) has been completely transferred from the blood side (9) via the membrane (10) of the dialyzer (6) into the dialysate side (11) and the blood side (9) of the dialyzer (6) is empty, continuing to set the negative pressure in the dialysate circuit (8) for causing air to be transferred from the blood side (9) via the membrane (10) of the dialyzer (6) into the dialysate side (11) and the liquid to be expelled from the dialysate side (11) of the dialyzer (6) to the dialysate drain (54) in order to also automatically empty the dialysate side (11) of the dialyzer (6), - a negative pressure is generated in the dialysate circuit (8) so that the flow pump outlet (48) is actuated to pump liquid or air from the dialyzer (6) into the dialysate drain (54), the flow pump being a fluid pump in the dialysate drain (54) of the dialysate circuit (8), and a compressor pump (34) arranged in the extracorporeal circuit (4) is actuated or manipulated so that it supports the transfer of air from the blood side (9) via the membrane (10) of the dialyzer (6) to the dialysate side (11).

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