Blood treatment device

Abstract

The invention relates to a blood treatment device (100) comprising or connected to at least one extracorporeal blood circulation (400), a pressure sensor (10) for detecting a prevailing fluid pressure in the extracorporeal blood circulation (400), a blood pump (4) for delivering blood through the extracorporeal blood circulation (400), a dialysate circulation (500), a blood leakage detector (23) for detecting the existence of blood in the dialysate circulation (500), a blood filter (200), comprising a dialysate chamber (200b), a blood chamber (200a) and a semipermeable membrane (200c) that divides both chambers. The blood treatment device also comprises an interrupting means, an open-loop or closed-loop control unit (60), wherein the open-loop or closed-loop control unit (60) is designed to operate the blood pump (4) in a first operating mode and, once a trigger event has been identified, to transfer into a further operating mode in which a delivery rate of the blood pump (4) is controlled in an open-loop manner on the basis of a specification or is controlled in a closed-loop manner to achieve a target value. The open-loop or closed-loop control unit (60) is also designed to activate the interruption means.

Description

[0001] Blood treatment device

[0002] Technical area

[0003] The invention relates to a blood treatment device with an extracorporeal blood circuit, a pressure sensor, a blood pump, a blood leak detector, a blood filter, an interruption means and a control or regulating unit.

[0004] background

[0005] Various types of blood treatment devices are known in the art. These include, for example, devices for hemodialysis, hemofiltration, ultrafiltration, and hemodiafiltration. In these blood treatment methods, blood is pumped through an extracorporeal blood circuit using a blood pump. During hemodialysis, the blood is purified by a dialyzer, which has a blood chamber located in the extracorporeal blood circuit and a second chamber, in particular a dialysate chamber, separated from each other by a semipermeable membrane. During a hemodialysis treatment, dialysis fluid flows through the dialysate chamber, with certain substances being transported through the membrane due to diffusion between the blood and the dialysis fluid and removed with the dialysis fluid via a dialysate circuit.In hemofiltration, certain substances are filtered from the blood through a semi-permeable membrane by convection. Hemodiafiltration, on the other hand, is a combination of both processes. In ultrafiltration, the second chamber is not dialysis fluid flowing through it, but rather water is removed from the blood through the semi-permeable membrane. The blood purification treatments of hemodialysis, hemofiltration, and hemodiafiltration can be combined with ultrafiltration.

[0006] The dialysate circuit contains a dialysis fluid pump to pump the dialysis fluid through the second chamber. An ultrafiltration pump can create the necessary negative pressure in the dialysis fluid chamber of the dialyzer to remove fluid from the patient to achieve the desired fluid balance.

[0007] Typically, the semi-permeable membrane of the dialyzer consists of a multitude of hollow fiber capillary walls. Blood flows through the densely arranged hollow fibers (blood chamber) and is surrounded by dialysate flowing through the dialyzer in the interstices between the hollow fibers (dialysate chamber). The integrity of the semi-permeable membrane ensures the separation of blood and dialysate.

[0008] Prior to delivery and use, existing dialyzers undergo tests at the factory during a blood treatment session to check the integrity of the membrane. A proven method for this involves a bubble point test, in which sterile air is forced into the dialysate chamber while sterile water is supplied to the blood chamber. If undesirable leaks occur in the membrane, air flows through the membrane and forms bubbles, which means the integrity test is failed, and the dialyzer is discarded. This integrity test minimizes the risk of capillary ruptures and blood leaks, as only those dialyzers that have successfully passed the integrity test are considered for use in blood treatment.

[0009] Nevertheless, capillary wall ruptures and associated blood leaks can occur during a blood treatment session. For this reason, common blood treatment devices incorporate various protective systems to protect the patient from potentially hazardous blood leaks. Such membrane leaks cause blood from the extracorporeal blood circuit to leak into the dialysate. One common protective system includes a blood leak detector.

[0010] The blood leak detector is typically located in a section of the dialysate line downstream of the dialyzer. During blood treatment, dialysate flows through the line. Thus, the blood leak detector operates in flow mode and generates a signal, such as an acoustic or visual alarm, if a predetermined limit characteristic of blood or a blood component is exceeded. Such a limit is regularly exceeded in the event of a blood leak, triggering the protective system and thus achieving a safe state that largely prevents blood loss into the dialysate.

[0011] Various measures can be initiated to achieve a safe condition. In addition to generating a signal, the blood pump can be stopped. Furthermore, the dialysate supply to the dialysate chamber can be interrupted. For example, a pump for pumping the dialysate can be stopped, or the dialysate side of the dialyzer can be bypassed. Furthermore, an ultrafiltration pump can be used to remove water from the blood by reducing the pressure on the dialysate side of the dialyzer.

[0012] It is an object of the present invention to propose a further blood treatment device which prevents increased blood loss into the dialysate.

[0013] The object of the invention is achieved by the blood treatment device having the features of claim 1.

[0014] Against this background, the invention proposes a blood treatment device, wherein the blood treatment device comprises a blood pump and a venous pressure sensor for the extracorporeal blood circuit, a dialysate circuit, and a blood leak detector on its hydraulic side, or is connected to such a device. The extracorporeal blood circuit is not part of the blood treatment device, but is integrated with it for the purpose of treating a patient's blood before the start of a blood treatment session. The extracorporeal blood circuit can be provided entirely or partially on a blood cassette or on a blood tubing set.

[0015] The blood pump is intended for pumping blood through the extracorporeal blood circuit during a blood treatment session when the circuit is connected to the extracorporeal blood circuit and to a blood filter, which can be configured as a dialyzer. The dialyzer, in turn, has a semi-permeable membrane separating a dialysate chamber and a blood chamber located in the dialyzer. For example, the blood pump can be configured as a peristaltic blood pump, and the blood transported in a tube can be pumped by the actuators of the peristaltic pump. The blood pump can be arranged upstream of the dialyzer. Upstream of the blood pump, a negative pressure can be generated by the blood pump, and upstream of the blood pump, a comparatively increased pressure can be generated.

[0016] Furthermore, the blood treatment device comprises at least one interrupting means. The at least one interrupting means can be suitable for blocking a fluid flow in the extracorporeal circuit.

[0017] The blood treatment device further comprises or is connected to a control or regulating unit. The control or regulating unit is designed or programmed to initiate, perform, control, and / or regulate specific functions or a method in cooperation with the blood treatment device, in particular as disclosed herein. Thus, it is designed, in particular, to control the blood pump and at least one interruption means.

[0018] Interaction can be or include actuation, control, or regulation. Interaction can be or require a signal connection.

[0019] In all the above and following statements, the use of the expression “may be” or “may have” etc. is to be understood as synonymous with “is preferably” or “preferably has” etc. and is intended to explain an embodiment of the invention.

[0020] Whenever numerical terms are mentioned herein, the skilled person will understand them as indicating a numerical lower limit. Unless this leads to a recognizable contradiction, the skilled person will therefore always read "at least one" or "at least one" alongside the reference to "a" or "an."

[0021] Whenever "programmed" or "trained" is mentioned herein, it is also disclosed that these terms can be interchanged. Advantageous further developments of the present invention are the subject of subclaims and embodiments.

[0022] When an embodiment is mentioned herein, this represents an exemplary embodiment according to the invention.

[0023] Embodiments according to the invention may comprise one or more of the features mentioned above and / or below in any technically possible combination.

[0024] In some embodiments of the blood treatment device according to the invention, the control or regulating unit is designed to operate the blood pump in a first operating mode and, after detection of a trigger event, to transfer it to a further operating mode in which a delivery rate of the blood pump is controlled based on a specification or regulated to a target value.

[0025] It has been recognized that normally during blood treatment, particularly during hemofiltration, hemodiafiltration, or ultrafiltration, a pressure gradient is created from the blood chamber to the second chamber to ensure the required flow across the semipermeable membrane, and that this pressure gradient is not instantly dissipated when the blood pump stops. Furthermore, it has been recognized that some blood pump designs have a certain inertia, which means that when the blood pump stops, an actuator in the blood pump stops with a time delay. Both of these aspects can contribute to a transmembrane pressure gradient continuing to exist in the event of, for example, a membrane rupture in the dialyzer, and this pressure gradient is only slowly dissipated, so that despite the blood pump stopping, further blood can be moved from the blood chamber to the second chamber.It was therefore recognized that it may be expedient to reduce the transmembrane pressure gradient as quickly as possible and / or to avoid the buildup of a higher transmembrane pressure gradient. In some embodiments, the first operating mode of the blood pump can be a mode in which the blood pump is operated for the purpose of blood treatment at predetermined rates or delivery rates that are characteristic of the treatment. Delivery rates can be in a range between 200 ml / min (milliliters per minute) and 500 ml / min. The further operating mode of the blood pump can be a mode in which the rate or delivery rate differs from that in the first operating mode, in that the blood pump stops or its delivery rate decreases.

[0026] In some embodiments, a triggering event as referred to above may be a detection of blood or a blood component in the dialysate circuit, wherein the event is triggered as a function of a determined value by means of the blood leak detector and the determined value exceeds a certain limit.

[0027] In some embodiments, the blood leak detector is an optical sensor comprising a blood leak channel, which in turn monitors the dialysate for blood content or the content of a blood component. The blood leak detector can detect different transmission behaviors of blood or the blood component for, for example, red and green light from an LED.

[0028] In some embodiments, blood leaks of less than 0.35 ml / min of blood, assuming a hematocrit of 32%, are considered a non-serious hazard situation.

[0029] In some embodiments, the at least one interruption means is arranged in or on the extracorporeal blood circuit, in particular in or on a venous line, or with an effect on the latter, wherein the control or regulating unit is designed to control the interruption means with the aim of counteracting a pressure increase in at least one section of the extracorporeal blood circuit and / or in the blood chamber of the blood filter in the further operating mode of the blood pump, in order to thus bring about a reduction in the transfer of blood from the blood chamber into the dialysate chamber as effectively as possible.

[0030] In some embodiments, the interruption means is or comprises a venous tube clamp, a valve, or a throttle, wherein the control or regulating unit is designed to actuate the interruption means. In this case, the interruption means can be closed. The control or regulating unit can be designed to keep the interruption means to be closed in an open state before closing in order to initiate the closing according to the invention. The interruption means can be a valve that is arranged downstream of the dialyzer.

[0031] The interruption device can be an actuator that

[0032] The hose line through which blood can be conveyed is closed by compressing the hose wall. This can block the flow of a fluid in the hose. The interruption means can be designed such that it remains open when energized and closes the line when de-energized. In other words, the control and regulating unit can generate a signal that stops energizing the interruption means, and the interruption means then blocks flow in the hose. The control or regulating unit can be designed to control the interruption means such that it closes completely or partially.

[0033] In some embodiments, the control or regulating unit of the blood treatment device according to the invention is designed to actuate the interruption means after a predetermined grace period has been reached or expired and / or a venous pressure in the extracorporeal circuit corresponding to a predetermined threshold has been reached or fallen below, following a point in time at which the blood pump was transferred to the further operating mode. The blood pump can be designed as a peristaltic pump, in particular as a roller squeeze pump. Such a roller squeeze pump is subject to a moment of inertia when its delivery rate is reduced or when stopped, wherein the pump delivers at a higher rate for a certain period of time immediately after reducing its delivery rate or during the stop process, compared to an expected rate that occurs after overcoming the moment of inertia.This continued pumping of the blood pump would cause a sudden increase in pressure in at least one section of the extracorporeal blood circuit and / or in the blood chamber of the blood filter if an interruption device were to be closed simultaneously with the initiation of the reduction in the flow rate or the initiation of the stop process of the blood pump. Such a pressure increase would result in blood continuing to be forced into the dialysate chamber of the blood filter in the event of capillary ruptures or a blood leak.

[0034] In some embodiments, the control or regulating unit is programmed to perform the following procedure during an extracorporeal blood treatment session, upon detection of blood in the dialysate circuit or upon an alarm detected or triggered by the blood leak detector.

[0035] The method comprises a transfer, in particular an immediate transfer of the blood pump from the first operating mode to the further operating mode in which a delivery rate of the blood pump is controlled based on a specification or regulated to a target value.

[0036] In some embodiments, the method comprises the following step: stopping the blood pump in the additional operating mode or reducing its delivery rate prior to transfer to the additional operating mode.

[0037] In some embodiments, the method initiated by the control or regulating unit comprises determining or ascertaining whether the predetermined grace period has been reached or exceeded and / or whether the pressure in the extracorporeal circuit, which corresponds to a threshold value, has been reached or fallen below. In some embodiments, the method initiated by the control or regulating unit comprises extending the grace period if a pressure value is detected at the venous pressure sensor that exceeds the predetermined threshold value.

[0038] In certain embodiments, the blood treatment device comprises at least one dialysate pump for conveying dialysate through the dialysate circuit, which is intended to be arranged in the dialysate side, in particular downstream or upstream of the dialysate chamber of the blood filter.

[0039] In certain embodiments of the blood treatment device according to the invention, the control or regulating unit is designed, alternatively or additionally to the above-described embodiments, to operate the dialysate pump in a first operating mode and, after detection of a trigger event, to transfer it to a further operating mode in which a delivery rate of the dialysate pump is controlled based on a specification or regulated to a target value.

[0040] In certain embodiments, the first operating mode of the dialysate pump may be a mode in which the dialysate pump is operated for the purpose of blood treatment at predetermined rates or delivery rates that are characteristic of the treatment. The further operating mode of the dialysate pump may be a mode in which the rate or delivery rate differs from that in the first operating mode.

[0041] In certain embodiments, the dialysate pump is designed as a feed pump, diaphragm pump or peristaltic pump.

[0042] In certain embodiments, the at least one interruption means is arranged in or on the dialysate circuit, in particular downstream of the dialysate chamber of the blood filter, or with effect on the latter, wherein the control or regulating unit is designed to control the interruption means in such a way that the interruption means is closed.

[0043] In certain embodiments in a first alternative, the dialysate pump delivers dialysate against the closed interruption means with the aim of causing a pressure increase in the dialysate chamber of the blood filter, thus building up a counterpressure or establishing a pressure gradient through the semipermeable membrane suitable for causing backfiltration of the dialysate or the dialysate mixed with blood into the capillaries of the blood chamber of the blood filter. The transmembrane pressure from the dialysate chamber to the blood chamber of the blood filter is positive or at least not negative. Blood leaking through or via the capillaries can thus be retained, or blood that has already leaked out can be redirected back into the blood chamber, particularly through intact capillaries.

[0044] In certain embodiments in a second alternative, the dialysate pump in the further operating mode pumps dialysate against the partially closed or opened interruption means, with the aim as described above in a certain embodiment in a first alternative. The delivery rate is increased in the further operating mode of the dialysate pump, preferably the dialysate pump is operated at its maximum delivery rate or in a range between 600 ml / min and 800 ml / min. Due to the design of the blood filter, wherein the cross-section perpendicular to the flow direction of the dialysate at the inlet and outlet is significantly smaller than the cross-section perpendicular to the flow direction of the dialysate into the blood filter, a back pressure occurs in the dialysate chamber of the blood filter at comparably high delivery rates, since the flow resistance in the outlet, due to the smaller cross-section, is higher than in the blood filter.

[0045] In some embodiments, the method initiated by the control or regulating unit comprises determining or establishing whether a time or pressure is within predetermined limits, exceeds or falls below a limit value, exceeds a minimum value, and / or does not exceed a maximum value. This can be done based on at least one criterion (limit value, range, maximum value, etc.), which can be stored, for example, in a memory device, such as the blood treatment device.

[0046] 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 an algorithm is stored in the control or regulating unit which enables the control of the blood pump according to the invention and the control of the interruption means according to the invention.

[0047] In some embodiments, the blood treatment device is designed as a dialysis device, hemodialysis device, hemofiltration device or hemodiafiltration device, in particular as a device for acute, chronic renal replacement therapy or for continuous renal replacement therapy (CRRT).

[0048] In some embodiments, the blood treatment device is specifically a hemofiltration device. Hemofiltration is a special form of hemodialysis. Here, too, the blood is fed into a special dialysis machine and filtered there. However, there is no dialysate and thus no mass transport by diffusion; instead, convection is maximized. Larger quantities of fluid are removed to enable detoxification, which is why they are reintroduced to the body in the form of electrolyte solutions. In this context, the term dialysate is synonymous with provided electrolyte solutions (substitution fluid), which the blood treatment device can supply to the extracorporeal blood circuit using, for example, a post-dilution valve. Furthermore, in this context, the term dialysate circuit is to be understood as referring to the hydraulic or water side of the blood treatment device.The hydraulic system has a supply line for substitution fluid and a drain line for filtered fluid, particularly blood or blood serum. A further development of hemofiltration is so-called iso-ultrafiltration, in which the hemofiltration described above is performed sequentially. Whenever ultrafiltration is mentioned, this includes iso-ultrafiltration.

[0049] In some embodiments, the extracorporeal blood circuit is a blood tubing set and / or a blood cassette or comprises a blood tubing set and / or a blood cassette.

[0050] By means of some embodiments of the invention, one or more of the advantages mentioned herein may be achievable, including the following:

[0051] The solution according to the invention can advantageously prevent increased blood transfer into the dialysate in the event of blood leaks due to capillary rupture or a rupture of the semi-permeable membrane. Thus, the patient does not suffer any disadvantageous increased blood loss with the procedure according to the invention, which advantageously contributes to patient well-being and patient safety.

[0052] Further details and advantages of the invention will become apparent from the figures and preferred embodiments discussed below. The blood treatment device according to the invention is described using the example of a hemodialysis device, but it can also be used in the same way in other blood treatment devices, such as a hemodiafiltration device. In the figures:

[0053] Brief description of the drawings

[0054] Fig. 1 shows a simplified schematic view of a fluid line structure of a blood treatment device according to the invention;

[0055] Fig. 2 shows schematically the pressure conditions in the extracorporeal

[0056] Blood circulation during a first operating mode of the blood pump; Fig. 3 schematically shows the sequence of the method according to the invention.

[0057] Detailed description of an embodiment

[0058] Fig. 1 shows a simplified schematic of a fluid line structure of a blood treatment device 100 according to the invention.

[0059] The blood treatment device 100 is connected to an extracorporeal blood circuit 400, which can be connected to the vascular system of the patient (not shown) for treatment via a double-needle access or a single-needle access. The blood circuit 400 can optionally be present in sections in or on a blood cassette.

[0060] The blood circuit 400 has, or is connected to, an arterial tube clamp 50 as the first tube clamp and an arterial connection needle 1 of an arterial line section 2. The blood circuit 400 further has, or is connected to, a venous tube clamp 53 as the second tube clamp and a venous connection needle 11 of a venous line section 6. An arterial pressure sensor 3 and / or a prefilter pressure sensor 5 can be provided in the arterial line section 2. Furthermore, a venous pressure sensor 10 and a venous chamber 9, optionally in fluid communication with a venting device 8 and / or with a single-needle chamber 7, can be provided in the venous line section 6. The venting unit 8 and the single-needle chamber 7 are each directly connected to a valve 51; 52.

[0061] The blood treatment device 100 is further connected to a dialysate circuit 500, in which dialysate is provided for treatment. For this purpose, the dialysate circuit 500 has a dialysate supply line section 20, into which fresh dialysate can be fed via line 31 into the dialysate supply line section 20, for example, by means of a balancing chamber 30. A dialysate inlet pressure sensor 21 and a dialysate inlet valve 54 can be provided in or on the dialysate supply line section 20. Furthermore, the dialysate circuit 500 has a dialysate discharge section 22, into which used dialysate is fed via the balancing chamber 30 into another line 32 and discarded by means of the discharge pump 25 arranged therein.Furthermore, the dialysate drainage section 22 can optionally be fluidically connected to an ultrafiltration line 27, wherein excess fluid is removed from the patient by means of the ultrafiltration pump 26 arranged therein and supplied to the further line 32. The dialysate drainage section 22 has a dialysate drain valve 55, a blood leak detector 23, and optionally a blood filter drain pressure sensor 24.

[0062] The blood filter 200 has the blood chamber 200a connected to the arterial line section 2 and the venous line section 6. The blood filter 200 also has the dialysate chamber 200b connected to the dialysate supply line section 20 and the dialysate discharge line section 22. The semipermeable membrane 200c of the blood filter 200 separates the two chambers from each other.

[0063] During hemodialysis, a patient's blood is pumped into the extracorporeal blood circuit 400, initially into the arterial line section 2, by means of the blood pump 4 via the arterial connection needle 1, and then fed into the blood chamber 200a of a blood filter 200, configured, for example, as a dialyzer. Through the semi-permeable membrane 200c, which can define the boundary between the extracorporeal blood circuit 400 and the dialysate circuit 500, the substances to be removed pass from the blood into the dialysate by diffusion and / or convection, whereby the substances to be removed are removed by the dialysate flowing in the dialysate chamber 200b in the opposite direction to the blood flow. At the same time, excess fluid can be removed from the patient's blood via a pressure gradient generated by the ultrafiltration pump 26 (ultrafiltration).The transmembrane pressure applied to the semi-permeable membrane 200c over the entire length of the blood filter 200 is always positive or adjusted such that blood plasma or fluid flows from the blood chamber 200a into the dialysate chamber 200b. The purified blood leaves the blood chamber 200a, is directed into the venous line section 6, and enters the venous chamber 9, where the purified blood is finally infused into the patient via the venous connection needle 11.

[0064] 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 therein. The control or regulating unit 60 controls, regulates, and monitors the blood treatment device 100 and can be in signal communication with each component mentioned herein.

[0065] Fig. 2 schematically shows pressure conditions of the extracorporeal blood circuit 400 during a first operating mode of the blood pump 4. The diagram is divided into four areas, with the areas referring to specific sections of the extracorporeal blood circuit 400 from the arterial connection needle 1 to the venous connection needle 11. The pressures shown represent a snapshot.

[0066] Section i refers to a region between the arterial inlet and a pump segment of a tube, in which a roller of the blood pump 4 is in contact with the tube. Section ii refers to a region between the blood pump and an inlet to the blood chamber 200a of the blood filter 200. Section iii shows the pressure conditions in the blood filter 200, in particular the pressure curve along the blood filter 200 at its semi-permeable membrane 200c. Section iv, in turn, refers to the venous line section 6.

[0067] The control and regulation unit 60 according to the invention is programmed to control the blood treatment device 100 using a method. The method can be executed during a blood treatment session. The further configurations, programming, or embodiments of the control and regulation unit are described below within the framework of the method according to the invention.

[0068] According to one embodiment of the method according to the invention, the patient is initially in an ongoing blood treatment session, with the arterial connection needle 1 and the venous connection needle 11 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 into the venous line section 6. The venous tube clamp 53 and the arterial tube clamp 50, as the interrupting means, are not closed. The blood filter 200 removes components to be removed from the blood, thereby purifying the blood.

[0069] A dialysate flow is established through the balancing chamber 30, with the open valves for the dialysate inlet 54 and outlet 55 ensuring unobstructed flow. Dialysate flows around the blood leak detector 23 downstream of the dialysate chamber 200b and monitors the dialysate drainage section 22 for the presence of blood during the blood treatment session. If a blood leak occurs due to breaks in the capillaries or ruptures in the blood filter 200, the blood that has undesirably entered the dialysate chamber 200b reaches the blood leak detector 23. In Fig. 1, blood that has passed through the semi-permeable membrane 200c of the blood filter 200 is identified by reference numeral 300. Such blood is referred to below as leaked blood 300. For graphical clarity, blood that has leaked in this way is schematically shown in a very simplified manner in the form of particles or drops.If the blood leak detector 23 detects leaking blood 300 and a threshold value for the presence of leaking blood 300 is exceeded, the blood leak detector 23 can, alternatively or additionally to the detection, be adapted or programmed to trigger an alarm as a result of the detection of leaking blood 300. This in turn leads to the method according to the invention being initiated or executed. Fig. 3 schematically shows the sequence of the method according to the invention. The detection of leaking blood 300 can define a triggering event, which is shown as S1. In addition, an alarm signal can optionally be triggered in conjunction with this, which alerts the treatment personnel that a malfunction is present. This is shown in S2a.

[0070] Accordingly, if leaked blood 300 has been detected in the extracorporeal blood circuit 400, or if an associated alarm is present, the control or regulating unit 60 initiates a particularly immediate transfer of the blood pump 4 from the first operating mode, in which no blood leakage prevailed, to the further operating mode, in which a delivery rate of the blood pump 4 is controlled, reduced, or regulated to a setpoint based on a specification. In Fig. 3, this step is shown as S2. In some embodiments, this comprises stopping the blood pump 4 or reducing or immediately reducing its delivery rate immediately before the detection of leaked blood 300. In particularly preferred embodiments, this comprises stopping the blood pump 4.

[0071] Simultaneously or overlapping, the invention provides that the interruption means, in particular the arterial tube clamp 50 and the venous tube clamp 53, initially maintain their open state and thus their state during operation of the blood pump 4 in its first operating mode after transferring the blood pump 4 to its second operating mode. In a particularly preferred embodiment, the venous tube clamp 53 maintains such a state.

[0072] Alternatively or additionally, in some embodiments, the valve 51 of the single-needle chamber 7 and / or the valve 52 of the ventilation unit 8 are opened by means of the control and regulation unit 60 when transferring to a further operating mode of the blood pump 4.

[0073] According to the invention, the continued delivery of the blood pump 4 is to be compensated for due to the moment of inertia acting on the pump 4, which would otherwise cause 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 an interruption means were to be closed simultaneously with the initiation of the reduction in the delivery rate or the initiation of the stopping process of the blood pump 4. Such a pressure increase would result in increased blood being forced into the dialysate chamber 200b of the blood filter in the event of capillary ruptures or a blood leak. The amount of leaked blood 300, as indicated in Fig. 1, would thus increase.

[0074] In a further method step, the respective interruption means maintains its open state until the control or regulating unit 60 causes the interruption means to finally be actuated after a predetermined grace period has been reached or expired and / or a venous pressure in the extracorporeal circuit 400 corresponding to a predetermined threshold value has been reached or fallen below, following a point in time at which the blood pump 4 was transferred to the further operating mode. This actually describes a time delay before the actual closing of the interruption means and is designated as step S3 in Fig. 3. Mechanical actuators and / or solenoid valves can be provided for this purpose. A person skilled in the art has a wide variety of configurations available for implementing the actuation of a wide variety of interruption means, so that detailed explanations will be omitted here.

[0075] The duration of the waiting period depends on the pump type, the previously set flow rate, the previously set transmembrane pressure, and the treatment type selected for the blood treatment session. Fig. 2 shows characteristic pressure conditions in the extracorporeal blood circuit 400 during hemodialysis treatment for a blood pump flow rate of 250 ml / min. A venous pressure sensor 10 is arranged in a region that represents region iv of Fig. 2. The pressure profile in regions i to iv can vary for a hemodiafiltration treatment, depending on whether a substitution 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).

[0076] If the blood pump 4 is preferably stopped during the subsequent operating mode, the pressure curve in the IV region approaches 0 mm Hg during the stopping process. If the blood pump 4 comes to a complete standstill, a pressure is established at the venous pressure sensor 10 that tends toward 0 mm Hg, is 0 mm Hg, or represents a static pressure value of the blood in the tube or tube section. Depending on the type of venous pressure sensor 10 used, the resolution of the determined pressure value is bound by design-specific limits. The determined pressure value can therefore deviate from the actual pressure value by, for example, 10-20 mm Hg.

[0077] The grace period thus refers to the time required for the blood pump 4 to come to a complete standstill after being transferred to the second operating mode. For this purpose, at least one value, determined, for example, through testing, can be stored in a memory device of the blood treatment device 100. Alternatively, a fixed time value can be stored, or the blood treatment device 100 can have a computing unit that calculates the time value for the grace period based on the prevailing conditions for the blood treatment session. The control and regulation unit 60 is in signal communication with the computing unit and is suitable for operating the blood treatment device 100 based on the calculated value.

[0078] In some embodiments, the control or regulating unit 60 can be configured to extend the grace period if a pressure value exceeding the predetermined threshold is detected at the venous pressure sensor 10. Such an optional step is designated as S3a in Fig. 3.

[0079] In some embodiments, as an alternative to the waiting period, the previously described pressure values ​​measured at the venous pressure sensor 10 are used as the initial trigger for activating the interruption means(s). The at least one pressure value required for this purpose can be stored in the memory device of the blood treatment device 100.

[0080] In a further method step, the interruption means is controlled to close after determining that the predetermined grace period has been reached and / or that the pressure in the extracorporeal circuit has been reached or fallen below a threshold value. Such a closure of an interruption means is designated as step 4 in Fig. 3. In a particularly preferred embodiment, the venous tube clamp 53 is closed. Alternatively or additionally, in some embodiments, the valve 51 on the single-needle chamber 7 and / or the valve 52 on the ventilation unit 8 are closed, provided they were previously opened in another method step.

[0081] Alternatively or in addition to the above-mentioned embodiment, in a first alternative, the control or regulating unit 60 can be programmed in certain embodiments such that, when the blood pump 4 has been transferred to the further operating mode, the dialysate drain valve 55 in the dialysate circuit 500 is actuated as an interruption means and consequently closed or partially closed, wherein the balancing chamber 30 is adjusted to allow a dialysate flow against the dialysate drain valve 55. Optionally, a further pump can be provided in the dialysate supply line section 20 for this purpose.

[0082] In a second alternative, in certain embodiments, the control and regulation unit 60 can be programmed such that, when the blood pump 4 has been transferred to the further operating mode, dialysate is passed through the dialysate chamber 200b at a higher rate in a further operating mode in the dialysate circuit 500 by means of the balancing chamber 30, the flow pump 25, and / or the ultrafiltration pump 26. Due to the design of the blood filter 200, wherein the cross-section perpendicular to the flow direction of the dialysate of the inlet 202 and outlet 201 is significantly smaller than the cross-section perpendicular to the flow direction of the dialysate into the blood filter 200, a back pressure is established in the dialysate chamber 200b of the blood filter 200 at comparably high flow rates, since the flow resistance in the outlet 201, due to the smaller cross-section, is higher than in the blood filter 200.The cross-sectional area of ​​the blood filter 200 may be at least two to forty times larger than the cross-sectional area of ​​the outlet 201, depending on the design or type of the blood filter 200.

[0083] Thus, in the case of the first and second alternatives, in certain embodiments, a pressure builds up in the dialysate chamber 200b that is suitable for conducting fluid from the dialysate chamber 200b via the semi-permeable membrane 200c into the blood chamber 200a. In particular, leaked blood 300 can be conducted into the blood chamber 200a. In this case, the blood pump 4 can optionally continue to pump blood or the blood-dialysate mixture so that the blood or the blood-dialysate mixture does not come to a standstill and blood clotting is advantageously avoided. The control and regulation unit 60 operates the blood pump 4 such that the pressure in the blood chamber 200a does not exceed the pressure in the dialysate chamber 200b. Thus, a neutral or negative transmembrane pressure is established in the blood filter 200.The transmembrane pressure can be evaluated by an evaluation unit of the blood treatment device 100 based on the direct measurement of the volume at the dialysate inlet pressure sensor 21 and the dialysate outlet pressure sensor 24, with the control and regulation unit 60 being programmed to change the dialysis flow volume such that no positive transmembrane pressure is established. Furthermore, the transmembrane pressure can be measured in a variety of ways, or its existence can be determined directly or indirectly. A wide variety of configurations are available to those skilled in the art, so detailed explanations will be omitted here.

Claims

Patent claims Blood treatment device 100 with or connected to at least one extracorporeal blood circuit 400; a pressure sensor 3; 10 for detecting a prevailing fluid pressure in the extracorporeal blood circuit 400; a peristaltic blood pump 4 for conveying blood through the extracorporeal blood circuit 400; a blood filter 200, comprising a dialysate chamber 200b and a blood chamber 200a; at least one interruption means suitable for blocking a flow in the extracorporeal blood circuit; a control or regulating unit 60, wherein the control or regulating unit 60 is designed to operate the blood pump 4 in a first operating mode and, after detecting a triggering event, to transfer it to a further operating mode, and further, the control or regulating unit 60 is designed to control the interruption means,wherein the interruption means consequently blocks the flow with a time delay according to a specification for transferring the blood pump into the further operating mode. 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. Blood treatment device 100 according to claims 1 or 2, characterized in that the control or regulating unit 60 is further designed such that, after a predetermined grace period has been reached or expired and / or a venous pressure in the extracorporeal circuit 400, which corresponds to a predetermined threshold value, has been reached or fallen below, and / or a transmembrane pressure, which corresponds to a predetermined, threshold value, is reached or undershot, following a point in time at which the blood pump 4 was transferred to the further operating mode, the interruption means is activated. Blood treatment device 100 according to claims 1 to 3, characterized in that the control or regulating unit 60 is designed to extend the grace period if a pressure value is detected at the venous pressure sensor 10 which exceeds the predetermined threshold value. Blood treatment device 100 according to one of the preceding claims, characterized in that the control or regulating unit 60 is designed to stop the blood pump 4 in the further operating mode or to reduce its delivery rate achieved before transfer to the further operating mode.Blood treatment device 100 according to one of the preceding claims, characterized in that the interruption means is arranged in or on the extracorporeal blood circuit 400, in particular in or on a venous line 6, or with effect on the latter. Blood treatment device 100 according to one of the preceding claims, characterized in that the interruption means is or comprises a venous hose clamp 53, a valve 51; 52, or a throttle, and wherein the control or regulating unit 60 is designed to control the interruption means such that it is closed. Blood treatment device 100 according to one of the preceding claims, characterized in that the blood treatment device 100 comprises a blood leak detector 23 for detecting the occurrence of blood. Blood treatment device 100 according to one of the preceding claims, characterized in that the blood treatment device 100 comprises a dialysate circuit 500 and the blood leak detector 23 is arranged in the dialysate circuit 500, in particular in a line section 22 downstream of the dialysate chamber 200b of the blood filter 200. Blood treatment device 100 according to one of the preceding claims, characterized in that the triggering event is a detection of blood in the dialysate circuit 500, wherein the event is triggered as a function of a determined value by means of the blood leak detector 23 and the determined value exceeds a specific limit value. Blood treatment device 100 according to one of the preceding claims, characterized in that the blood leak detector 23 is an optical or acoustic sensor.Blood treatment device 100 according to one of the preceding claims, characterized in that the control or regulating unit 60 is programmed to carry out a method for controlling a blood treatment device 100 during a blood treatment session, the method comprising the following steps following detection of blood or following an alarm detected or triggered by the blood leak detector 23:. Transferring the blood pump 4 from the first operating mode to the further operating mode in which a delivery rate of the blood pump 4 is reduced; Determining whether the predetermined waiting time has been reached and / or determining whether the pressure in the extracorporeal circuit 400, which corresponds to a threshold value; Controlling the interruption means such that it is closed. The blood treatment device 100 according to claim 12, further comprising the step: Stopping the blood pump 4 in the further operating mode or reducing its delivery rate immediately before transfer to the further operating mode. Blood treatment device 100 according to claim 12 or 13, further comprising the step: Extending the grace period if a pressure value is detected at the venous pressure sensor 10 that exceeds the predetermined threshold. The blood treatment device 100 according to any one of claims 12 to 14, characterized in that the control or regulating unit 60 is programmed to initiate some or all of the method steps disclosed in the preceding claims in any combination. The blood treatment device 100 according to any one of the preceding claims, wherein the blood treatment device 100 is configured as a dialysis device, hemodialysis device, hemofiltration device, ultrafiltration device, or hemodiafiltration device, in particular as a device for acute, chronic renal replacement therapy, or continuous renal replacement therapy (CRRT).

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