Blood treatment device

Abstract

The invention relates to a blood treatment device (100) comprising or respectively connected to: at least one extracorporeal blood circuit (400); a pressure sensor (10) for measuring a current fluid pressure in the extracorporeal blood circuit (400); a blood pump (4) for conveying blood through the extracorporeal blood circuit (400); a dialysate circuit (500); a blood leak detector (23) for sensing blood escape in the dialysate circuit (500); a blood filter (200) includes a dialysate chamber (200b), a blood chamber (200a), and a semipermeable membrane (200c) separating the two chambers. Furthermore, the blood treatment device (100) comprises at least one interruption mechanism, a control or regulation unit (60), the control or regulation unit (60) being designed to operate the blood pump (4) in a first operating mode and to switch the blood pump into a further operating mode, in which the blood pump (4) is operated in a second operating mode after a trigger event is detected, the delivery rate of the blood pump (4) is controlled or adjusted to a target value on the basis of a preset value. Furthermore, the control or regulation unit (60) is designed to activate an interruption mechanism.

Description

Technical Field

[0001] The invention relates to a blood treatment device, which comprises an extracorporeal blood circuit, a pressure sensor, a blood pump, a blood leakage detector, a blood filter, an interruption mechanism and a control or regulation unit. Background Art

[0002] In the prior art, various types of blood treatment devices are known. They include, for example, devices for hemodialysis, hemofiltration, ultrafiltration and hemodiafiltration. In the method of blood treatment mentioned, blood is guided via an extracorporeal blood circuit by means of a blood pump. In the case of hemodialysis, blood is purified by a dialyzer having a blood chamber and a second chamber, particularly a dialysate chamber, present in the extracorporeal blood circuit, which are separated from each other by a semipermeable membrane. During hemodialysis treatment, the dialysis fluid flows through the dialysate chamber, and the diffusion between the blood and the dialysis fluid causes certain substances to be transported through the membrane and removed together with the dialysis fluid via the dialysate circuit. In the case of hemofiltration, convection causes certain substances to be filtered out of the blood through a semipermeable membrane. In contrast, hemodiafiltration is a combination of two methods. In the case of ultrafiltration, the dialysis fluid does not flow through the second chamber; alternatively, water is removed from the blood only through a semipermeable membrane. Hemodialysis, hemofiltration and hemodiafiltration blood purification treatments can be combined with ultrafiltration.

[0003] A dialysate fluid pump is present in the dialysate circuit for delivering dialysate fluid through the second chamber. The ultrafiltration pump can generate the necessary negative pressure in the dialysate fluid chamber of the dialyzer so that fluid can be removed from the patient to achieve the desired fluid balance.

[0004] The semipermeable membrane of the dialyzer is usually composed of the capillary walls of multiple hollow fibers. The blood flows through the tightly arranged hollow fibers (blood chamber), while the dialysate flowing through the dialyzer flows around the blood in the hollow fiber gaps (dialysate chamber). The integrity of the semipermeable membrane ensures the separation of blood and dialysate.

[0005] Prior to delivery and use during a blood treatment period, known dialyzers are subjected to a factory test in which the integrity of the membrane is checked. A method that has proven itself in practice for this purpose provides a bubble point test, which involves pressing sterile air into the dialysate chamber, while the blood chamber receives sterile water. If an undesired leak occurs in the membrane, air will flow through the membrane and form bubbles, which means that the integrity test has failed and the dialyzer is discarded. This integrity check minimizes the risk of capillary rupture and blood leakage, since only dialyzers that have successfully passed the integrity test are considered for blood treatment.

[0006] Nevertheless, during a blood treatment session, ruptures of the capillary walls and associated blood leakage may occur. It is for this reason that common blood treatment devices have various protection systems that protect the patient from blood leakage, which could lead to dangerous situations for the patient. Such leaks in the membrane lead to blood entering the dialysate from the extracorporeal blood circuit. One protection system known from practice includes a blood leak detector.

[0007] The blood leak detector is usually arranged in a line section of the dialysate line downstream of the dialyzer, wherein the dialysate flows through this line during the blood treatment, and the flow-through operation of the blood leak detector is thus performed and the blood leak detector generates a signal, such as an acoustic or optical alarm, if a predetermined limit characteristic of the blood or a blood component is exceeded. If a blood leak occurs, the limit is often exceeded, resulting in a response of the protection system, which is intended to achieve a safety state in which the loss of blood into the dialysate is prevented as much as possible.

[0008] Various measures can be initiated to achieve a safe state. In addition to generating a signal, the blood pump can also be stopped. Furthermore, the supply of dialysate into the dialysate chamber can be interrupted. For example, the pump for pumping the dialysate can be stopped, or the dialysate side of the dialyzer can be bridged by means of a bypass. Furthermore, an ultrafiltration pump can also be used to remove water from the blood by reducing the pressure on the dialysate side of the dialyzer. Summary of the invention

[0009] The object of the present invention is to propose an alternative blood treatment device which prevents an increased loss of blood into the dialysate.

[0010] This object is achieved according to the invention by a blood treatment device having the features of claim 1 .

[0011] Against this background, a blood treatment device is proposed according to the invention, wherein the blood treatment device comprises or is respectively connected to: a blood pump and a venous pressure sensor for an extracorporeal blood circuit, a dialysate circuit and a blood leak detector on its hydraulic side. The extracorporeal blood circuit is not part of the blood treatment device; rather, it is assembled and connected before the start of a blood treatment session for treating the patient's blood. The extracorporeal blood circuit can be arranged completely or partially on a blood cassette or a blood hose set.

[0012] When the blood pump is connected to the extracorporeal blood circuit and the blood filter, the blood pump is used to convey blood through the extracorporeal blood circuit during the blood treatment period, and the blood filter can be in the form of a dialyzer, and the dialyzer itself has a semipermeable membrane, and the semipermeable membrane separates the dialysate chamber and the blood chamber present in the dialyzer. For example, the blood pump can be in the form of a peristaltic blood pump, and the blood conveyed in the hose can be pumped by the actuator of the peristaltic pump. The blood pump can be arranged upstream of the dialyzer. In the upstream of the blood pump, negative pressure can be generated by the blood pump, and in the upstream of the blood pump, a relatively increased pressure can be generated.

[0013] Furthermore, the blood treatment apparatus comprises at least one interruption mechanism. The at least one interruption mechanism may be suitable for interrupting the flow of fluid in the extracorporeal circuit.

[0014] The blood treatment device further comprises a control or regulation unit or is connected to such a unit. The control or regulation unit is designed or programmed to cooperate with the blood treatment device to start, execute, control and / or regulate specific functions or methods, in particular those disclosed herein. For example, the control or regulation unit is particularly designed to activate the blood pump and at least one interruption mechanism.

[0015] Collaboration may be or include activation, control or regulation. Collaboration may be or require a signal connection.

[0016] In all the above and following discussions, the use of the expression “may be” or “may have” etc. should be understood as being synonymous with “preferably” or “preferably has” etc. and is intended to explain embodiments according to the present invention.

[0017] Whenever numerical values ​​are mentioned herein, the skilled person will understand that they represent numerical lower limits. As long as this does not lead to a contradiction that is obvious to the skilled person, the skilled person will therefore always infer, for example, "at least one" when indicating "one".

[0018] If reference is made herein to "programmed" or "designed", it is also disclosed that these terms are interchangeable.

[0019] Advantageous developments of the invention are respectively subject matter of the dependent claims and the exemplary embodiments.

[0020] If an embodiment is mentioned herein, it is an exemplary embodiment according to the invention.

[0021] Embodiments according to the invention may include one or more of the features mentioned above and / or below in any technically possible combination.

[0022] In some embodiments of the blood treatment device according to the present invention, the control or regulation unit is designed to operate the blood pump in a first operating mode and, after detecting a triggering event, switch the blood pump to another operating mode, in which the delivery rate of the blood pump is controlled based on a preset value or the delivery rate of the blood pump is adjusted to a target value.

[0023] We have recognized that, usually during blood treatment, particularly during hemofiltration, hemodiafiltration or ultrafiltration, a pressure gradient from the blood chamber to the second chamber will be established to meet the flow required for passing the semipermeable membrane, and when the blood pump stops, the pressure gradient will not be reduced immediately. In addition, we have recognized that in the case of some blood pump concepts, the pump has a certain inertia, as a result, when the blood pump stops, the actuator of the blood pump stops with a time delay. Both of these aspects can contribute to the continued existence of the transmembrane pressure gradient in the case of a membrane rupture such as in a dialyzer and the slow reduction of the transmembrane pressure gradient, which means that although the blood pump stops, other blood can be transferred to the second chamber from the blood chamber. Therefore, we have recognized that it may be appropriate to reduce the transmembrane pressure gradient as quickly as possible and / or avoid setting up a relatively high transmembrane pressure gradient.

[0024] In some embodiments, the first operating mode of the blood pump may be a mode in which the blood pump is operated for the purpose of blood therapy at a predetermined rate or a delivery rate characteristic of the therapy. The delivery rate characteristically may be in the range between 200 ml / min (milliliters per minute) and 500 ml / min. Another operating mode of the blood pump may be a mode in which the rate or delivery rate differs from the rate or delivery rate in the first operating mode in that the blood pump is stopped or its delivery rate is reduced.

[0025] In some embodiments, as described above, the triggering event may be the detection of blood or blood components in the dialysate circuit, wherein the event is triggered by means of a blood leak detector depending on a determined value and the determined value exceeds a certain threshold.

[0026] In some embodiments, the blood leak detector is an optical sensor, wherein the optical sensor includes a blood leak channel, wherein the blood leak channel in turn monitors the blood content or blood component content of the dialysate. The blood leak detector can detect the different transmission behaviors of blood or blood components for red and green light of, for example, a light emitting diode.

[0027] In some embodiments, at an assumed hematocrit value of 32%, a blood leak of less than 0.35 ml / min of blood is considered a non-critical condition.

[0028] In some embodiments, the at least one interruption mechanism is arranged in or on the extracorporeal blood circuit, in particular in or on the venous line, or acts on the venous line, wherein the control or regulation unit is designed to activate the interruption mechanism in order to counteract the pressure increase in at least one section of the extracorporeal blood circuit and / or in the blood chamber of the blood filter in another operating mode of the blood pump, so as to thereby reduce the flow of blood from the blood chamber into the dialysate chamber as effectively as possible.

[0029] In some embodiments, the interruption mechanism is or includes a venous hose clamp, a valve or a butterfly valve, wherein the control or regulation unit is designed to activate the interruption mechanism. Here, the interruption mechanism can be closed. The control or regulation unit can be designed to keep the interruption mechanism to be closed in an open state before closing, so as to cause the closure according to the present invention. The interruption mechanism can be a valve arranged downstream of the dialyzer. The interruption mechanism can be an actuator, which closes the hose line by compressing the hose wall, and blood can be transported in the hose line. As a result, the flow of fluid in the hose can be blocked. The interruption mechanism can be designed so that it remains open in a flowing state, and it closes the pipeline in a non-flowing state. In other words, the control and regulation unit can generate a signal, by means of which the flow through the interruption mechanism is stopped, and the interruption mechanism therefore blocks the flow in the hose. The control or regulation unit can be designed to activate the interruption mechanism so that it is completely or partially closed.

[0030] In some embodiments, the control or regulating unit of the blood treatment device according to the present invention is designed to activate the interruption mechanism after the blood pump has been switched to another operating mode and has reached or passed a predetermined waiting time and / or the venous pressure in the extracorporeal circuit has reached or is lower than the corresponding predetermined threshold value. The blood pump can be in the form of a peristaltic pump, in particular a roller pump. This roller pump is affected by the moment of inertia when its delivery rate is reduced or when shutdown occurs, and the pump delivers at a higher rate for a period of time immediately after its delivery rate is reduced or during the shutdown process compared to the expected rate established after overcoming the moment of inertia. If the interruption mechanism is closed while starting to reduce the delivery rate or starting the shutdown process of the blood pump, this continuous delivery of the blood pump will cause the pressure in at least one section of the extracorporeal blood circuit and / or the blood chamber of the blood filter to rise suddenly. In the case of capillary rupture or blood leakage, this pressure increase will cause blood to continue to be pushed into the dialysate chamber of the blood filter.

[0031] In some embodiments, the control or regulation unit is programmed to perform the following method during an extracorporeal blood treatment session after detection of blood in the dialysate circuit or after detection or triggering of an alarm by a blood leak detector.

[0032] The method comprises switching the blood pump from a first operating mode, in particular immediately, into a further operating mode in which the delivery rate of the blood pump is controlled based on a preset value or is adjusted to a target value.

[0033] In some embodiments, the method comprises the following steps: Stopping the blood pump in the other operating mode or reducing the delivery rate it produces before switching to the other operating mode.

[0034] In some embodiments, the method initiated by the control or regulation unit comprises determining or establishing whether a predetermined waiting time has been reached or exceeded and / or whether the pressure in the extracorporeal circuit has reached or fallen below a respective threshold value.

[0035] In some embodiments, the method initiated by the control or regulation unit comprises extending the waiting time if a pressure value exceeding a predetermined threshold is detected at the venous pressure sensor.

[0036] In certain embodiments, the blood treatment apparatus comprises at least one dialysate pump for conveying dialysate through the dialysate circuit, which dialysate pump is intended to be arranged downstream or upstream of the dialysate chamber on the dialysate side, in particular of the blood filter.

[0037] In certain embodiments of the blood treatment device according to the present invention, as an alternative or supplement to the above-mentioned embodiments, the control or regulation unit is designed to operate the dialysate pump in a first operating mode and, after detecting a triggering event, switch the dialysate pump to another operating mode, in which the delivery rate of the dialysate pump is controlled based on a preset value or the delivery rate of the dialysate pump is adjusted to a target value.

[0038] In some embodiments, the first operating mode of the dialysate pump can be a mode in which the dialysate pump operates at a predetermined rate or delivery rate characteristic of the treatment for the purpose of blood treatment. Another operating mode of the dialysate pump can be a mode in which its rate or delivery rate is different from the rate or delivery rate in the first operating mode.

[0039] In certain embodiments, the dialysate pump is in the form of a feed pump, a diaphragm pump, or a peristaltic pump.

[0040] In certain embodiments, at least one interruption mechanism is arranged in or on the dialysate circuit, in particular downstream of the dialysate chamber of the blood filter, or acts on the dialysate circuit, wherein the control or regulation unit is designed to activate the interruption mechanism so that the interruption mechanism is closed.

[0041] In some embodiments, in a first alternative, the dialysate pump delivers dialysate toward the closed interruption mechanism, with the purpose of causing a pressure increase in the dialysate chamber of the blood filter, thereby establishing a back pressure or setting a pressure gradient through the semipermeable membrane, the back pressure / pressure gradient being suitable for back-filtering the dialysate or blood-mixed dialysate into the capillaries of the blood chamber of the blood filter. The transmembrane pressure from the dialysate chamber of the blood filter to the blood chamber is positive or at least not negative. Thus, blood can be prevented from escaping through or through the capillaries, or blood that has already escaped can be directed back into the blood chamber, in particular through intact capillaries.

[0042] In some embodiments, in the second alternative, the dialysate pump delivers dialysate towards a partially closed or open interruption mechanism in another operating mode, the purpose of which is as described above in a certain embodiment in the first alternative. In this case, the delivery rate is increased in another operating mode of the dialysate pump; preferably, the dialysate pump is operated at its maximum output or in a range between 600 ml / min and 800 ml / min. Due to the structure of the blood filter, in which the cross-sections perpendicular to the dialysate flow direction in the inlet and outlet are substantially smaller than the cross-sections perpendicular to the dialysate flow direction entering the blood filter, a back pressure in the dialysate chamber of the blood filter is established at a relatively high output, because the flow resistance in the outlet is higher than the flow resistance in the blood filter due to the smaller cross-section.

[0043] In some embodiments, the method initiated by the control or regulation unit comprises determining or establishing whether the time or pressure is within a predetermined limit, exceeds or falls below a limit, exceeds a minimum value and / or does not exceed a maximum value. This can be done based on at least one criterion (limit, range, maximum value, etc.), which can be stored, for example, in a storage device, for example in a storage device of a blood treatment device.

[0044] The design of the control or regulating unit according to the invention is based on the fact that it is connected to the relevant components of the blood treatment device and that algorithms are stored in the control or regulating unit which allow the activation according to the invention of the blood pump and the activation according to the invention of the interruption mechanism.

[0045] In some embodiments, the blood treatment device is in the form of a dialysis device, a hemodialysis device, a hemofiltration device, or a hemodiafiltration device, particularly in the form of a device for acute renal replacement therapy, chronic renal replacement therapy, or continuous renal replacement therapy (CRRT).

[0046] In some embodiments, the blood treatment device is specifically a blood filtration device. Blood filtration is a special form of hemodialysis. Here, blood is also directed to a specific dialyzer, where the blood is filtered. However, despite the maximization of convection, dialysate and diffusion mass transfer do not exist. A relatively large amount of fluid is removed to allow detoxification, which is why they are resupplied to the body in the form of an electrolyte solution. In this regard, the term dialysate is synonymous with the electrolyte solution (replacement fluid) provided, and the blood treatment device can supply the electrolyte solution to the extracorporeal blood circuit by means of, for example, a post-dilution valve. In addition, in this regard, the term dialysate circuit should be understood to represent the hydraulic side or water side of the blood treatment device. For this purpose, the hydraulic system includes a supply line for the replacement fluid and a discharge line for the filtered fluid (especially blood or serum). A development of blood filtration is the so-called iso-ultrafiltration, in which blood filtration as described above is performed in sequence. Whenever ultrafiltration is mentioned, iso-ultrafiltration is included.

[0047] In some embodiments, the extracorporeal blood circuit is a blood hose set and / or a blood cassette, or comprises a blood hose set and / or a blood cassette.

[0048] By means of some embodiments according to the present invention, one or more advantages mentioned herein can be achieved, and the following is one of the advantages:

[0049] The solution according to the invention can advantageously prevent the blood from flowing more into the dialysate in the case of blood leakage due to capillary rupture or semipermeable membrane rupture. Therefore, in the method according to the invention, the patient will not suffer from increased blood loss, and this advantageously contributes to the health and safety of the patient.

[0050] Further details and advantages of the invention will emerge from the drawings and preferred exemplary embodiments discussed below. The blood treatment device according to the invention will be described using the example of a hemodialysis device, but it can also be used similarly for other blood treatment devices, such as a hemodiafiltration device.

[0051] In the attached figure: BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The fluid line structure of the blood treatment device according to the present invention is schematically shown in simplified form;

[0053] Figure 2 schematically illustrates the pressure conditions in the extracorporeal blood circuit during a first operating mode of the blood pump;

[0054] Figure 3 The sequence of the method according to the invention is schematically shown. DETAILED DESCRIPTION

[0055] Figure 1 The fluid line structure of a blood treatment device 100 according to the invention is schematically shown in simplified form.

[0056] The blood treatment device 100 is connected to an extracorporeal blood circuit 400, which can be connected to the vascular system of a patient (not shown) by means of a double needle access or by means of a single needle access for treatment. Optionally, the blood circuit 400 can be present in or on a blood box with its sections.

[0057] The blood circuit 400 comprises or is connected to an arterial hose clamp 50 as a first hose clamp and an arterial connection needle 1 of the arterial line section 2. The blood circuit 400 also comprises or is connected to a venous hose clamp 53 as a second hose clamp and a venous connection needle 11 of the venous line section 6. The arterial pressure sensor 3 and / or the pre-filter pressure sensor 5 can be arranged in the arterial line section 2. In addition, the venous pressure sensor 10 and the venous chamber 9 can be arranged in the venous line section 6, and the venous chamber 9 is optionally fluidly connected to the ventilation unit 8 and / or to the single needle chamber 7. The ventilation unit 8 and the single needle chamber 7 are directly connected to the valves 51, 52, respectively.

[0058] Furthermore, the blood treatment apparatus 100 is connected to a dialysate circuit 500, in which dialysate is provided for treatment. For this purpose, the dialysate circuit 500 comprises a dialysate supply line section 20, into which fresh dialysate can be guided via a line 31 by means of, for example, a balancing chamber 30. A dialysate inflow pressure sensor 21 and a dialysate inflow valve 54 can be arranged in or on the dialysate supply line section 20. Furthermore, the dialysate circuit 500 comprises a dialysate discharge line section 22, into which the spent dialysate is guided by means of a discharge line pump 25 arranged therein, and is guided via the balancing chamber 30 into a further line 32 and discharged. Furthermore, the dialysate discharge line section 22 can optionally be fluidically connected to an ultrafiltration line 27, into which an ultrafiltration pump 26 arranged therein is used to remove excess fluid from the patient and supply it to a further line 32. The dialysate discharge line section 22 includes a dialysate outflow valve 55 , a blood leak detector 23 and an optional blood filter outflow pressure sensor 24 .

[0059] The blood filter 200 includes a blood chamber 200a connected to the arterial line section 2 and the venous line section 6. Furthermore, the blood filter 200 includes a dialysate chamber 200b connected to the dialysate supply line section 20 and the dialysate discharge line section 22. A semipermeable membrane 200c of the blood filter 200 separates the two chambers from each other.

[0060] In the case of hemodialysis, the patient's blood is guided into the extracorporeal blood circuit 400 via the arterial connection needle 1 by means of a blood pump 4, first into the arterial line section 2, and supplied to the blood chamber 200a of a blood filter 200, for example in the form of a dialyzer. The substances to be removed pass from the blood into the dialysate by diffusion and / or convection through a semipermeable membrane 200c, which can define the boundary between the extracorporeal blood circuit 400 and the dialysate circuit 500, wherein the substances to be removed are removed by the dialysate flowing in the dialysate chamber 200b in the opposite direction of the blood flow. At the same time, excess fluid from the blood can be removed from the patient via a pressure gradient that can be generated by an ultrafiltration pump 26 (ultrafiltration). In this case, the transmembrane pressure on the semipermeable membrane 200c over the entire length of the blood filter 200 is always positive or is set so that plasma or fluid enters the dialysate chamber 200b from the blood chamber 200a.

[0061] The purified blood leaves the blood chamber 200 a , is guided to the venous line section 6 and enters the venous chamber 9 , and the purified blood is finally infused into the patient's body via the venous connecting needle 11 .

[0062] Pumps, actuators, sensors, detectors, hose clamps and / or valves in the area of ​​the blood circuit 400 and the dialysate circuit 500 are connected to the blood treatment device 100 according to the invention or to a control or regulating unit 60 comprised by the blood treatment device 100. The control or regulating unit 60 controls, regulates and monitors the blood treatment device 100 and can be signal-connected to each of the components mentioned herein.

[0063] Figure 2 Schematically shown is the pressure condition of the extracorporeal blood circuit 400 during the first operating mode of the blood pump 4. The graph is divided into four areas, which relate to certain sections of the extracorporeal circuit 400 from the arterial connection needle 1 to the venous connection needle 11. The pressure shown is an instantaneous condition.

[0064] Section i relates to the area between the arterial inflow and the pump section of the hose, in which the rollers of the blood pump 4 are in contact with the hose. Section ii relates to the area between the blood pump and the inlet of the blood chamber 200a of the blood filter 200. Section iii shows the pressure conditions in the blood filter 200, in particular the pressure distribution along the blood filter 200 at its semipermeable membrane 200c. Section iv relates to the venous line section 6.

[0065] The control and regulating unit 60 according to the invention is programmed to control the blood treatment apparatus 100 by means of a method. The method can be performed during a blood treatment session.

[0066] A further configuration, programming or design of the control and regulating unit will be described below in the context of the method according to the invention.

[0067] In an exemplary embodiment of the method according to the invention, the patient is first in an ongoing blood treatment session, wherein the arterial connection needle 1 and the venous connection needle 11 are connected to the patient. The blood pump 4 pumps blood at a preset pumping rate through the arterial line section 2 into the blood chamber 200a and back to the venous line section 6. At the same time, the venous hose clamp 53 and the arterial hose clamp 50 as interruption mechanisms are not closed. The components to be removed are extracted from the blood by means of the blood filter 200, thereby purifying the blood.

[0068] The dialysate flow rate is set by the balancing chamber 30, wherein unimpeded flow is ensured by the dialysate inflow valve 54 and the dialysate outflow valve 55, which are not closed. The dialysate flows around the blood leak detector 23 downstream of the dialysate chamber 200b, and the blood leak detector 23 monitors the presence of blood in the dialysate discharge line section 22 during a blood treatment session. If there is a blood leak due to a rupture in the capillary or a rupture in the blood filter 200, blood that has undesirably entered the dialysate chamber 200b reaches the blood leak detector 23. Figure 1 , the blood that has passed through the semipermeable membrane 200c of the blood filter 200 is identified by reference numeral 300. Such blood is hereinafter referred to as leaking blood 300. For illustration purposes, the blood leaking in this manner is schematically depicted in a highly simplified manner in the form of particles or droplets. If the blood leak detector 23 detects leaking blood 300 and if a threshold value for the presence of leaking blood 300 is exceeded, the blood leak detector 23 may be adapted or programmed to trigger an alarm due to the detection of leaking blood 300, as an alternative or in addition to the detection. This in turn causes the method according to the invention to be initiated or performed. Figure 3 The sequence of the method according to the invention is schematically shown. Here, the detection of leaking blood 300 can define a triggering event, which is depicted as S1. In addition, this can be associated with the optional triggering of an alarm signal, which draws the attention of the treating staff to the fact that there is a fault. This is shown in S2a.

[0069] If leaking blood 300 has thus been detected in the extracorporeal blood circuit 400, or if an associated alarm is present, the control or regulating unit 60 initiates a switch, in particular an immediate switch, of the blood pump 4 from a first operating mode in which there is no blood leakage into another operating mode in which the delivery rate of the blood pump 4 is controlled or reduced based on a preset value or is adjusted to a target value. Figure 3In some embodiments, this includes stopping the blood pump 4 or reducing or immediately reducing its output immediately before detecting the leaking blood 300. In a particularly preferred embodiment, this includes stopping the blood pump 4.

[0070] According to the invention, simultaneously or in an overlapping manner, after the blood pump 4 has been switched to its second operating mode, the interruption mechanism, in particular the arterial hose clamp 50 and the venous hose clamp 53, initially remain in their open state, i.e. in the state they were in during the operation of the blood pump 4 in the first operating mode. In a particularly preferred embodiment, the venous hose clamp 53 remains in this state.

[0071] Alternatively or additionally, in some embodiments, in the event of a switch to another operating mode of the blood pump 4 , the control and regulating unit 60 opens the valve 51 of the single-needle chamber 7 and / or the valve 52 of the ventilation unit 8 .

[0072] According to the invention, the aim is to compensate for the continuous delivery through the blood pump 4 due to the moment of inertia acting on the pump 4, which otherwise would lead to a sudden increase in pressure in at least one section of the extracorporeal blood circuit 400 and / or in the blood chamber 200a of the blood filter 200 if the interruption mechanism is closed at the same time as the start of a reduction in the delivery rate or the start of a shutdown process of the blood pump 4. In the event of a capillary rupture or a blood leak, this pressure increase would lead to an increased push of the blood into the dialysate chamber 200b of the blood filter. Figure 1 As shown, the amount of leaked blood 300 will therefore increase.

[0073] In a further method step, the respective interruption mechanism remains in its open state until, after a predetermined waiting time has been reached or has elapsed after the moment when the blood pump 4 has switched to another operating mode and / or after the venous pressure in the extracorporeal circuit 400 has reached or fallen below a respective predetermined threshold value, the control or regulating unit 60 finally initiates activation of the interruption mechanism. This actually describes a time delay before the actual closing of the interruption mechanism, and Figure 3 In the step S3, a mechanical actuator and / or a solenoid valve may be provided for this purpose. Various designs are available to those skilled in the art for activating various interruption mechanisms, so no further details are provided here.

[0074] The duration of the waiting time depends on the pump type, the previously set delivery rate, the previously set transmembrane pressure and the type of therapy selected for the blood therapy session. Figure 2 4 shows characteristic pressure conditions in the extracorporeal blood circuit 400 during a hemodialysis treatment for a blood pump delivery rate of 250 ml / min. The venous pressure sensor 10 is arranged at the position indicated. Figure 2The pressure distribution in regions i to iv may vary for a hemodiafiltration treatment, depending on whether the replacement fluid is introduced into the extracorporeal blood circuit 400 into a line section upstream of the blood filter 200 (pre-dilution) or into a line section downstream of the blood filter 200 (post-dilution).

[0075] If the blood pump 4 is preferably stopped in another operating mode, the pressure distribution in the region iv is close to 0 mm Hg during the shutdown process. If the blood pump 4 is completely stopped, a pressure tending to 0 mm Hg or being 0 mm Hg or representing the static pressure value of the blood in the hose or hose section is established at the venous pressure sensor 10. Depending on the type of venous pressure sensor 10 to be used, the resolution of the determined pressure value is associated with the typical limits of the design. Therefore, the determined pressure value can deviate from the actual pressure value, for example, by 10-20 mm Hg.

[0076] The waiting time is thus based on the time period required for the blood pump 4 to be completely stopped after switching to the second operating mode. For this purpose, at least one value determined, for example, by tests can be stored in a storage device of the blood treatment device 100. Furthermore, as an alternative, a fixed time value can be stored, or the blood treatment device 100 can have a calculation unit, which calculates the time value of the waiting time based on the current conditions of the blood treatment session. The control and regulation unit 60 is signal-connected to the calculation unit and is suitable for operating the blood treatment device 100 based on the calculated value.

[0077] In some embodiments, the control or regulation unit 60 may be designed to extend the waiting time if a pressure value exceeding a predetermined threshold is detected at the venous pressure sensor 10. This optional step may be Figure 3 is designated as S3a.

[0078] In some embodiments, instead of a waiting time, the pressure value measured at the venous pressure sensor 10 already described is used as a starting point for activating the interruption mechanism or mechanisms. The required at least one pressure value can be stored in a memory device of the blood treatment device 100 .

[0079] In a further method step, the interruption mechanism is controlled such that it is closed after it has been determined that a predetermined waiting time has been reached and / or after it has been determined that the pressure in the extracorporeal circuit has reached or fallen below a corresponding threshold value. Figure 3 In the embodiment designated as step 4. In a particularly preferred embodiment, the venous hose clamp 53 is closed. Alternatively or additionally, in some embodiments, if the valve 51 of the single needle chamber 7 and / or the valve 52 of the ventilation unit 8 were previously opened in another method step, they are closed.

[0080] As an alternative or in addition to the above exemplary embodiments, in a first alternative, the control or regulating unit 60 in certain embodiments may be programmed so that when the blood pump 4 has switched to another operating mode, the dialysate outflow valve 55 in the dialysate circuit 500 is activated as an interruption mechanism and is thus closed or partially closed, and the balancing chamber 30 is arranged to allow the dialysate to flow toward the dialysate outflow valve 55. Optionally, a further pump may be provided in the dialysate supply line section 20 for this purpose.

[0081] In a second alternative, in certain embodiments, the control and regulation unit 60 may be programmed such that, when the blood pump 4 has been switched to another operating mode, the dialysate in the dialysate circuit 500 in the other operating mode is guided at a higher rate through the dialysate chamber 200b by means of the balancing chamber 30, the flow pump 25 and / or the ultrafiltration pump 26. Due to the structure of the blood filter 200, in which the cross-sections perpendicular to the dialysate flow direction in the inlet 202 and the outlet 201 are substantially smaller than the cross-sections perpendicular to the dialysate flow direction entering the blood filter 200, a back pressure in the dialysate chamber 200b of the blood filter 200 is established at a relatively high output, because the flow resistance in the outlet 201 is higher than the flow resistance in the blood filter 200 due to the smaller cross-section. Depending on the design or model of the blood filter 200, the cross-sectional area of ​​the blood filter 200 may be at least two to four times larger than the cross-sectional area of ​​the outlet 201.

[0082] Therefore, in certain embodiments, in the case of the first and second alternatives, a pressure suitable for guiding the fluid from the dialysate chamber 200b through the semipermeable membrane 200c to the blood chamber 200a is established in the dialysate chamber 200b. In particular, the leaking blood 300 can be guided into the blood chamber 200a. Optionally, at the same time, the blood pump 4 can continue to convey blood or a blood / dialysate mixture so that the blood or the blood / dialysate mixture does not stop, and the coagulation of the blood is advantageously avoided. The control and regulation unit 60 operates the blood pump 4 so that the pressure in the blood chamber 200a is not greater than the pressure in the dialysate chamber 200b. Therefore, a neutral or negative transmembrane pressure is established in the blood filter 200. The transmembrane pressure can be evaluated by means of a direct measurement of the volume at the dialysate inflow pressure sensor 21 and the dialysate outflow pressure sensor 24 by means of an evaluation unit of the blood treatment device 100, and the control and regulation unit 60 is programmed to change the dialysis flow in a manner that does not establish a positive transmembrane pressure. In addition, the transmembrane pressure can be measured in various ways, and its presence can be determined directly or indirectly. To this end, various designs are available to those skilled in the art, so the details will not be provided here.

Claims

1. A blood treatment device (100), comprising or respectively connected to at least: - Extracorporeal blood circuit (400); - a pressure sensor (3; 10) for measuring the current fluid pressure in the extracorporeal blood circuit (400); a peristaltic blood pump (4) for conveying blood through an extracorporeal blood circuit (400); - a blood filter (200) comprising a dialysate chamber (200b) and a blood chamber (200a); - at least one interruption mechanism, which is suitable for blocking the flow in the extracorporeal blood circuit; - a control or regulation unit (60), wherein The control or regulation unit (60) is designed to operate the blood pump (4) in a first operating mode and, after detecting a triggering event, to switch the blood pump (4) to another operating mode, and The control or regulating unit (60) is also designed to activate the interruption mechanism, wherein the interruption mechanism then interrupts the flow with a time delay according to a preset time after the blood pump switches to another operating mode.

2. The blood treatment device (100) according to claim 1, characterized in that: The pressure sensor is a venous pressure sensor (10) or comprises a venous pressure sensor (10).

3. The blood treatment device (100) according to claim 1 or 2, characterized in that: The control or regulation unit (60) is also designed so that the interruption mechanism is activated after a predetermined waiting time has been reached or has elapsed after the moment when the blood pump (4) has been switched to the other operating mode and / or after the venous pressure in the extracorporeal blood circuit (400) has reached or fallen below a corresponding predetermined threshold value and / or after the transmembrane pressure has reached or fallen below a corresponding predetermined threshold value.

4. The blood treatment device (100) according to claims 1-3, characterized in that: The control or regulating unit (60) is designed to extend the waiting time if a pressure value exceeding a predetermined threshold value is detected at the venous pressure sensor (10).

5. The blood treatment device (100) according to any one of the preceding claims, characterized in that The control or regulating unit (60) is designed to stop the blood pump (4) in the other operating mode or to reduce the delivery rate of the blood pump (4) which is produced before switching to the other operating mode.

6. The blood treatment device (100) according to any one of the preceding claims, characterized in that The interruption mechanism is arranged in or on the extracorporeal blood circuit (400), in particular in or on the venous line (6), or acts on the venous line (6).

7. The blood treatment device (100) according to any one of the preceding claims, characterized in that The interruption mechanism is or comprises a venous hose clamp (53), a valve (51; 52) or a butterfly valve, and the control or regulating unit (60) is designed to activate the interruption mechanism so that the interruption mechanism is closed.

8. The blood treatment device (100) according to any one of the preceding claims, characterized in that The blood treatment apparatus (100) comprises a blood leak detector (23) for sensing the escape of blood.

9. The blood treatment device (100) according to any one of the preceding claims, characterized in that The blood treatment apparatus (100) comprises a dialysate circuit (500), and a blood leak detector (23) is arranged in the dialysate circuit (500), in particular, in a pipeline section (22) downstream of a dialysate chamber (200b) of a blood filter (200).

10. The blood treatment device (100) according to any one of the preceding claims, characterized in that The triggering event is the detection of blood in the dialysate circuit (500), wherein the event is triggered by means of a blood leak detector (23) according to a determined value, and the determined value exceeds a certain threshold value.

11. The blood treatment device (100) according to any one of the preceding claims, characterized in that The blood leak detector (23) is an optical sensor or an acoustic sensor.

12. The blood treatment device (100) according to any one of the preceding claims, characterized in that The control or regulation unit (60) is programmed to perform a method for controlling a blood treatment device (100) during a blood treatment session, wherein the method comprises the following steps which are implemented after the detection of blood or after the detection or triggering of an alarm by a blood leak detector (23): - switching the blood pump (4) from a first operating mode to another operating mode in which the delivery rate of the blood pump (4) is reduced; - determining that a predetermined waiting time has been reached and / or determining that the pressure in the extracorporeal circuit (400) has reached or fallen below a corresponding threshold; - Activate the interruption mechanism so that it is closed.

13. The blood treatment device (100) according to claim 12, further comprising the following steps: - in another operating mode, stopping the blood pump (4) or reducing its delivery rate which is generated immediately before switching to another operating mode.

14. The blood treatment device (100) according to claim 12 or 13, further comprising the following steps: - If a pressure value exceeding a predetermined threshold is detected at the venous pressure sensor (10), the waiting time is extended.

15. The blood treatment device (100) according to any one of claims 12 to 14, characterized in that: The control or regulation unit (60) is programmed to initiate some or all of the method steps disclosed in the preceding claims in any combination.

16. The blood treatment device (100) according to any one of the preceding claims, wherein: The blood treatment device (100) is in the form of a dialysis device, a hemodialysis device, a hemofiltration device, an ultrafiltration device or a hemodiafiltration device, in particular in the form of a device for acute renal replacement therapy, chronic renal replacement therapy or continuous renal replacement therapy CRRT.

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