Control or regulation device and blood treatment device for single needle treatment

Description

[0001] The present invention relates to a control or regulating device (hereinafter referred to as control device) of a blood treatment device according to claim 1. It also relates to a blood treatment device according to claim 4.

[0002] An artificial single-needle kidney is disclosed in EP 0 143 064 A1.

[0003] Devices for extracorporeal blood treatment are known in practice, in which blood is withdrawn from the patient for extracorporeal blood treatment via a vascular access with only one needle (e.g. so-called "single-needle dialysis") and returned to the patient.

[0004] In single-needle procedures for extracorporeal blood treatment, a distinction is made between a so-called arterial phase, in which blood is withdrawn from the patient via a cannula, for example, and the so-called venous phase or return phase, in which the blood is returned to the patient's vascular system via the same single cannula. Between these two phases, the blood is purified in a blood treatment device, usually a blood filter or dialyzer. In the known devices and methods for single-needle treatment, the blood is also temporarily stored between these phases in a buffer container located in the extracorporeal blood circuit (i.e., on the blood side) to enable switching between the two phases.

[0005] The single-needle technique is characterized by the use of only one cannula or single-lumen catheter, or, more generally, only one vascular access device, through which patient blood is alternately pumped, e.g., from a shunt, especially a short one, to the dialysis machine and, after purification, back to the patient. This technique is used particularly in emergency situations.

[0006] The single-needle treatment procedure is described in more detail in DRUKKER, PARSONS and MAHER, 5th Edition, Kluwer Academic Publishers, Dordrecht, 2004, page 365.

[0007] The object of the present invention may be to provide a control device and a blood treatment device which are suitable or configured to carry out the method disclosed herein.

[0008] The object of the invention is achieved by a control or regulating device having the features of claim 1, and by a blood treatment device having the features of claim 4.

[0009] In all the 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 embodiments of the invention.

[0010] Whenever numerical terms are mentioned herein, the person skilled in the art will understand this as an indication of a numerical lower limit.

[0011] Unless this leads to a contradiction recognizable to the skilled person, the skilled person will therefore always read "at least one" or "at least one" alongside the term "a" or "an." This understanding is encompassed by the present invention, as is the interpretation that a numerical word such as "a" can alternatively be meant as "exactly one," wherever this is recognizably technically possible to the skilled person. Both are encompassed by the present invention and apply to all numerical words used herein.

[0012] Whenever reference is made to "programmed" or "configured" herein, it is also disclosed that these terms may be used interchangeably.

[0013] In case of doubt on the part of the person skilled in the art, the terms "top" and "bottom" are to be understood as absolute or relative spatial specifications which refer to the orientation of the component in question during its normal use.

[0014] The blood tubing set disclosed herein is suitable for single-needle treatment.

[0015] It comprises a patient tubing line which is intended or arranged to withdraw blood from the patient's bloodstream and to introduce it into the blood tubing set, as well as to return blood from the blood tubing set into the patient's bloodstream.

[0016] The blood tubing set disclosed herein further comprises a Y-shaped connector or a three-way connector. The connector is connected to the patient tubing.

[0017] However, the blood tubing set does not have a blood-side single-needle chamber or is not connected to a blood-side single-needle chamber, especially in fluid communication.

[0018] When reference is made herein to "blood side," this term refers to those sections through which the blood to be treated flows or is pumped extracorporeally during blood treatment, or which are connected to it, such as an arterial pressure gauge, an optical density meter, etc. A set of blood tubing would therefore be assigned to the blood side (since blood flows through it during use), while lines by means of which dialysis fluid is conveyed to the blood filter or dialysate is conveyed away from the blood filter, like other sections of the blood treatment device, are referred to as the machine side or hydraulic side.

[0019] When referred to herein as a single-needle chamber, this refers to a storage device for temporarily storing blood or whole blood between a step of withdrawing blood through the patient tubing and the subsequent step of returning it through the patient tubing. An alternative term for "single-needle chamber" is, for example, "compliance chamber." These terms may be used interchangeably herein.

[0020] When reference is made here to a single-needle chamber, this does not refer to a blood filter or a dialyzer with a mostly semi-permeable membrane. Single-needle chambers and blood filters or dialyzers are understood here as different, separate components.

[0021] The blood tubing set disclosed herein may be an extracorporeal blood circuit.

[0022] The control device according to the invention is configured or designed to control or regulate a blood treatment device for treating blood by means of a single-needle method.

[0023] The blood treatment device comprises a blood pump that can be connected to a blood tubing set—for example, one according to the invention—for example, as described above. The pump is designed to pump blood through the blood tubing set, wherein it can be operated in a withdrawal direction and preferably, in particular alternately, also in a return direction (i.e., for example, backward).

[0024] The blood treatment device to be controlled has a return pump. The return pump can, for example, be the blood pump that pumps in the opposite direction for return, for example. Alternatively or additionally, the return pump can be or comprise a compressed air source, a hydraulic pump, a dialysis fluid pump, a substituate pump, or any other pump. The return pump is optionally arranged to pump fluid toward the blood tubing set or a portion thereof in a return direction during use of the blood treatment device. Alternatively, the return pump is optionally connectable to the blood tubing set according to the invention or a portion thereof or configured to be in fluid communication therewith in order to pump blood through the blood treatment device and / or through the blood tubing set in a return direction.

[0025] Here, the control device is configured or programmed to carry out a method by means of the blood treatment device, which comprises the following steps a) and b) alternately several times: a) The blood pump is operated in a withdrawal direction, in which blood is withdrawn from the patient's bloodstream and pumped along a patient tubing line into the blood tubing set according to the invention. In this step, it thus withdraws blood from the patient. The volume of blood withdrawn in this step can, for example, be between 30 ml and 100 ml. b) The return pump is operated in a return direction. In this way, blood is pumped out of the blood tubing set and pumped back into the patient's bloodstream along the patient tubing line. The volume of blood returned ("reinfused") to the patient in this step is between 30 ml and 100 ml. To achieve a balanced volume or mass balance, the volume should preferably correspond to the blood volume withdrawn in step a).After completion of step b), a new cycle of steps a) and b) can be started by beginning another step a).

[0026] The blood is not stored in a blood-side single-needle chamber between its collection in step a) and its return in step b).

[0027] The blood treatment device according to the invention, which is suitable for performing single-needle blood treatment, comprises a blood pump that can be connected to a blood tubing set, for example, as described above. The pump is designed to pump blood through the blood tubing set, being operable in a withdrawal direction and preferably, e.g., alternately, also in a return direction.

[0028] The blood treatment device comprises a return pump. The return pump can, for example, be the blood pump that pumps in the opposite direction for return, for example. Alternatively or additionally, the return pump can be a compressed air source, a hydraulic pump, a dialysis fluid pump, a substituate pump, or any other pump. The return pump is optionally arranged to pump fluid toward the blood tubing set or a portion thereof in a return direction during use of the blood treatment device. Alternatively, the return pump is connectable to the blood tubing set according to the invention or a portion thereof or is configured to be in fluid communication therewith in order to serve or contribute to pumping blood through the blood tubing set in a return direction.

[0029] Furthermore, the blood treatment device according to the invention comprises a control or regulating device (in short: control device) which is configured or programmed to control or regulate the blood treatment device. The control device is configured or programmed to carry out a method by means of the blood treatment device, which comprises the following steps a) and b), which can also be referred to as the arterial phase and venous phase, in multiple alternating steps: a) The blood pump is operated in a withdrawal direction, in which blood is withdrawn from the patient's bloodstream and pumped along a patient tubing line into the blood tubing set disclosed herein. In this step, it thus withdraws blood from the patient. The volume of blood withdrawn in this step can, for example, be between 30 ml and 100 ml. b) The return pump is operated in a return direction. As a result, blood is pumped out of the blood tubing set and back along the patient tubing line into the patient's bloodstream. The volume of blood returned ("reinfused") to the patient in this step is between 30 ml and 100 ml. This volume will correspond to the blood volume withdrawn in step a). A new cycle of withdrawal and return can follow.

[0030] The blood is not stored in a blood-side single-needle chamber between its collection in step a) and its return in step b).

[0031] The method disclosed herein for purifying blood by a single-needle method is carried out by means of a blood treatment device according to the invention.

[0032] When using a blood tubing set for single-needle treatment as disclosed herein, in particular within the scope of one of the blood treatment methods described herein, blood is not temporarily stored in a blood-side single-needle chamber or a blood-side compliance chamber, i.e. not in a single-needle chamber or compliance chamber that is part of the blood tubing set and / or is provided on the blood side.

[0033] Embodiments of the invention may, based on one of the independent claims, comprise one or more of the features mentioned above or below. The features mentioned herein may be the subject of embodiments of the invention based on one of the independent claims in any combination, provided that a person skilled in the art does not recognize a specific combination as technically impossible.

[0034] Whenever an embodiment is mentioned herein, it is an exemplary embodiment according to the invention, based on one of the independent claims.

[0035] In some embodiments, blood is not temporarily stored in a machine-side single-needle chamber or a machine-side compliance chamber, i.e., not in a single-needle chamber or compliance chamber that is part of the hydraulic system and / or provided on the hydraulic system side.

[0036] In some embodiments, the blood tubing set does not have a patient tubing line in addition to a patient tubing line, but only one patient tubing line in total, which would be connected to the patient's vascular circuit and / or to an access device.

[0037] In some embodiments, the blood tubing set has exactly one access device for establishing access between the patient tubing and the patient's blood circuit.

[0038] An access device may be, for example, a needle, a connector, etc. and is preferably single-lumen.

[0039] In some embodiments, the membrane may have high membrane permeability (high flux).

[0040] In some embodiments, the method according to the invention, as well as the method carried out by the control device, optionally further comprises closing a venous clamp or tube clamp located downstream of the blood treatment device (blood filter, dialyzer, etc.) or otherwise preventing the blood flow downstream of the blood treatment device during or before blood is conveyed from the patient towards the blood filter in the above-mentioned step a).

[0041] Furthermore, the control device causes the transfer of volume, such as plasma or blood water from the pumped blood, across the semi-permeable membrane of the blood filter by creating a pressure difference, e.g., a pressure gradient between the blood chamber and the dialysis fluid chamber. This can be supported or achieved, for example, by active hydraulic ultrafiltration using one or more ultrafiltration pumps and / or passively by volume displacement while reducing the pressure increase generated by the blood pump in the blood filter.

[0042] Finally, in some embodiments, the method performed by the control device includes opening the venous tube clamp or ceasing to otherwise clamp it.

[0043] Alternatively or additionally, in some embodiments, the method or the method performed by the control device comprises causing fluid to pass from the dialysis fluid chamber through the semi-permeable membrane into the blood chamber of the blood filter. This can be achieved, for example, by building up a suitable pressure on the hydraulic side or the dialysis fluid side (dialysis side) while, in the above-mentioned step b), blood is pumped back into the patient's bloodstream along the patient tubing.

[0044] In some embodiments, for example, in this step, the addition of substituate fluid optionally occurs via a substituate addition point of the blood tubing set, e.g., via a connector and e.g., from a substituate source, instead of or in addition to the return of fluid across the membrane. This can serve to displace blood and return blood to the patient, or can support this process. A volume shift in step b) across the membrane of the blood filter can therefore be omitted or supplemented in these embodiments.

[0045] The method comprises controlling and / or monitoring the method by analyzing pressure measurement values, in particular of the arterial and / or venous pressure sensor, and / or the motor current consumption of at least one of the pumps mentioned herein.

[0046] In some embodiments, step a) is terminated, for which purpose either the withdrawal activity of the blood pump is stopped or reduced or (alternatively or additionally) the return activity of the return pump is started or increased, when, for example, the transmembrane pressure has reached or exceeded a value predetermined for the phase of step a). This value can be higher than other values ​​that were previously set as limit values ​​for the transmembrane pressure during other phases of the blood treatment. If the value predetermined for step a) is reached / exceeded, a maximum desired or permissible hemoconcentration of the blood in the blood chamber of the blood filter is deemed to have been reached. The devices according to the invention can be configured to carry out or effect this embodiment—as well as any other embodiment disclosed herein.

[0047] In some embodiments, the method comprises a phase inserted between step a) (e.g., its end) and step b) (e.g., its beginning), referred to herein as an interim phase or step c). During this phase, the blood pump and optionally also the return pump can be stopped or significantly slowed down. During this interim phase, the venous tube clamp can optionally be closed. The blood present in the blood chamber can be forced to remain in the blood chamber. During this interim phase, dialysis fluid can flow through the dialysis fluid chamber of the blood filter. The time period during which flushing occurs in this way can, for example, be more than 1 second, in particular between 1 and 30 seconds.The time during which flushing occurs in this manner can be limited to (or equal to) the time it takes for a predetermined volume of dialysis fluid to flow through the dialysis fluid chamber of the blood filter. This volume can be set, for example, to 1-3 times the fluid volume of the dialysis fluid chamber.

[0048] Inserting or providing such an interim phase can increase the efficiency of blood purification, as during this phase, fresh dialysis fluid is passed over concentrated blood, separated by the semi-permeable membrane. It is the exploitation of the high concentration during the interim phase that leads to increased diffusive separation of uremic toxins from the blood by filtration, thus resulting in the aforementioned increase in efficiency.

[0049] In some embodiments, the interim phase described above is not strictly inserted between the withdrawal phase and the return phase, such that either the withdrawal phase, the interim phase, or the return phase would run. While this is precisely the case in some embodiments, in other embodiments, two of the aforementioned phases always overlap, i.e., either the withdrawal phase with the interim phase (which presumably can no longer be referred to as "interim"), or the interim phase with the return phase.

[0050] The interim phase may optionally no longer exist in isolation, but is accompanied by withdrawal flows or return flows throughout its entire duration.

[0051] Thus, in some embodiments, during the withdrawal phase referred to herein as step a), the pumps provided on the hydraulic side of the blood treatment device (one located upstream of the dialysis fluid chamber of the blood filter, the other downstream of this chamber) can be used to generate a lower pressure or negative pressure (relative to the blood chamber) in the dialysis fluid chamber, while simultaneously maintaining a dialysis fluid flow through the dialysis fluid chamber. In this way, both filtration and dialysis, i.e., blood purification via both convection and diffusion, can also occur in step a).

[0052] Likewise, in some embodiments, it may be provided, additionally or alternatively, to generate a higher pressure or overpressure (relative to the blood chamber) in the dialysis fluid chamber by means of the aforementioned pumps during the return phase referred to herein as step b), while simultaneously maintaining a dialysis fluid flow through the dialysis fluid chamber. In this way, both volume substitution and dialysis can also occur in step b).

[0053] In some embodiments, the control device is configured to control or regulate the aforementioned pumps, as described above, depending on the control of the blood pump, the return pump, and / or valves or clamps such as the venous tube clamp. For example, it can be programmed or configured to start the dialysis fluid flow along the semi-permeable membrane (without passing through it) after the induced transfer of plasma water across the semi-permeable membrane is complete, for example, because the blood pump is stopped or the venous tube clamp is or has been opened. Likewise, it can be configured to terminate the dialysis fluid flow along the membrane as soon as the transfer of fresh dialysis fluid or substituate or another fluid for infusion into the patient across the membrane to the blood side is to begin.

[0054] In some embodiments, the blood treatment device is designed as a hemodialysis device, a hemofiltration device or a hemodiafiltration device, in particular as a device for chronic renal replacement therapy or for continuous renal replacement therapy (CRRT = continuous renal replacement therapy ) .

[0055] The blood treatment device can be designed as a device for acute treatment, and dialysis fluid can be provided, for example, by means of bags.

[0056] The blood treatment device can be designed as a device for long-term treatment or for the treatment of patients requiring long-term dialysis, and dialysis fluid can, for example, be mixed online by the treatment device.

[0057] In some embodiments, the blood pump also serves as the return pump. The blood pump can be operated alternately in a withdrawal direction and a return direction. Alternatively or additionally, the opening and closing of fluid paths within the blood tubing set can result in blood being withdrawn from the patient and returned to the patient at times, even when only one pump, e.g., the blood pump, is operating.

[0058] In some embodiments, no single-needle chamber or compliance chamber is provided, not even on the hydraulic side. In particular, no single-needle chamber or compliance chamber is provided that serves as an oscillation volume or volume for receiving and subsequently discharging fluid between the dialysis fluid chamber and a waste pump or an ultrafiltration pump and is connected to a line between the dialysis fluid chamber and a waste pump or an ultrafiltration pump, in particular via a branch line, or branches off from it.

[0059] A compliance chamber is not understood here as a volume that results or is created when elastic fluid lines, such as arterial blood lines or venous blood lines, expand beyond their nominal or resting volume under increased internal line pressure and can thus accommodate more volume than before. While this effect is also commonly referred to as "compliance" (of the lines), the latter only describes a behavior of the material of the existing line. However, this material behavior is not a "compliance chamber," as used herein. Rather, a "compliance chamber" would be a chamber that is recognizable as such and that optionally has no other function than temporarily storing fluid. It can be fluidically connected to a line, e.g., fluidically integrated into it or connected to it via a branch line.However, a compliance chamber is optionally recognizably designed as such and / or is distinct from the management that feeds it. If one were to eliminate the compliance chamber, the management that feeds it would remain optional.

[0060] In some embodiments, the blood treatment device comprises a feed pump for conveying fresh dialysis fluid toward the dialysis fluid chamber and a waste pump for conveying used dialysate away from the dialysis fluid chamber.

[0061] Some or all embodiments of the invention may have one, several or all of the advantages mentioned above and / or below.

[0062] Conventional, completely air-free extracorporeal blood tubing systems lack the option of temporarily storing patient blood during the aforementioned phase changes (transition between withdrawal and return). While the single-needle procedure can be implemented in such systems using switchable single-needle chambers, this requires complex mimicry for the phase-synchronized provision of a demand-based storage volume. The required control of the blood treatment device is therefore comparatively complex. Furthermore, the required blood tubing system can be significantly more complex than, for example, in the double-needle procedure, in which blood is continuously withdrawn and returned via two vascular accesses.With the aid of the invention described herein, it is advantageously possible to dispense with both the complex mimicry for the phase-synchronized provision of the storage volume and a complex control system as well as a complex blood tubing set.

[0063] Blood purification can nevertheless be advantageously achieved through a combination of diffusive and convective mass exchange.

[0064] Because the extracorporeal bloodline system can remain completely free of air, blood / air contact and the associated risk of coagulation are advantageously reduced or even eliminated. Blood / air contact, like blood stagnation, leads to an increased tendency for thrombus formation in the bloodline system, necessitating increased use of anticoagulants. According to the invention, this increases patient safety. Furthermore, anticoagulants can be advantageously saved and / or their use reduced.

[0065] A further advantage is that, apart from conventional pumps such as blood pumps or ultrafiltration pumps, no additional actuator is required in the extracorporeal blood circuit. The procedure can therefore be implemented in existing device systems with little effort.

[0066] The present invention is explained below by way of example with reference to the accompanying drawings, in which like reference numerals designate identical or similar components. In the figures: Fig. 1 shows a simplified representation of a blood treatment device according to the invention with an extracorporeal blood circuit in a first embodiment; Fig. 2a shows, by way of example, in graphic representation the schematic structure of the blood tubing set disclosed herein in use during a collection phase; and Fig. 2b shows an example of the schematic structure of the blood tubing set of the Fig. 2a during a return phase; and Fig. 2c shows an example of the schematic structure of the blood tubing set of the Fig. 2a and 2b during an optional intermediate or interim phase.

[0067] Fig. 1 shows in a simplified representation an exemplary embodiment of a blood treatment device 4 according to the invention, connected to a blood tubing set or extracorporeal blood circuit 1. The blood treatment device 4 of the Fig. 1 is a device for treating patients requiring long-term dialysis. However, the blood treatment device 4 according to the invention is not limited to this.

[0068] The extracorporeal blood circuit 1 runs purely exemplarily outside and inside a blood cassette 2 and fluidically connects it to the treatment device 4. The extracorporeal blood circuit 1 has or is connected to precisely one access device 10, for example, a connection needle. Fluid flow through the extracorporeal blood circuit 1 or through sections thereof can be prevented by means of an arterial tube clamp 6 arranged in its arterial blood line 8, and further by means of a venous tube clamp 7 arranged in its venous blood line 9.

[0069] A section of the extracorporeal blood circuit 1 is inserted into a blood pump 11 of the blood treatment device 4. The extracorporeal blood circuit 1 optionally has an addition point 13 for substituate fluid (in pre-dilution) and an optional addition point 14 for substituate fluid (in post-dilution). The addition points 13 and 14 are exemplified here as phantom valves. Phantom valves of this type are described in WO 2010 / 121819 A1 by the applicant and the present invention. For details, reference is made to that published application.

[0070] An optional arterial air-blood detector 15 is optionally provided on the arterial blood line 8.

[0071] Fig. 1 further optionally shows a substituate pump 17 of the blood treatment device 4. This is located downstream of a connection point at which the blood cassette 2 can optionally be connected with its substituate port 18a to an optional, automatic substituate connector 18b of the blood treatment device 4 before use. The automatic substituate connector 18b has in the example of Fig. 1 optionally a first fluid guide 3, a second fluid guide 5 and a third fluid guide for flushing the automatic substituate connector 18b and for guiding substituate through the automatic substituate connector 18b.

[0072] In the extracorporeal blood circuit 1, a blood filter 19 with a blood chamber 19a and a

[0073] Dialysis fluid chamber 19b is switched on. Blood chamber 19a and dialysis fluid chamber 19b are separated from each other by a semi-permeable membrane 19c.

[0074] The blood cassette 2 optionally has a venous air separation chamber 21.

[0075] A substituate line of the blood cassette 2 optionally has a check valve 23.

[0076] The extracorporeal blood circuit 1 optionally has a venous air-substituate fluid-blood detector 25 on the venous blood line 9.

[0077] The blood treatment device 4 optionally has or is connected to a compressed air source 26.

[0078] In Fig. 1 Furthermore, a dialysis fluid supply line 31a, which leads dialysis fluid to the dialysis fluid chamber 19b, and a dialysate drain line 31b, which leads dialysate away from the dialysis fluid chamber 19b, can be seen.

[0079] A pressure sensor 33a is optionally provided upstream of the blood pump 11 in the arterial blood line 8.

[0080] A pressure sensor 33b is optionally provided in the area of ​​the venous air separation chamber 21 in the venous blood line 9.

[0081] A pressure sensor 33c, also referred to as a prefilter pressure sensor, is optionally provided downstream of the blood pump 11 in the arterial blood line 8. This can be arranged upstream of the addition point 13.

[0082] Another pressure sensor 37 is optionally located in or on the dialysis fluid supply line 31a between the pressure source 26 and the blood filter 19.

[0083] Valves V19, V22, V24, V25, V26, V28, V31, V32 and V33 are optional and provided in sections of the hydraulic system of the blood treatment device 4.

[0084] The valve V24 is located in or on the dialysis fluid supply line 31a.

[0085] The valve V25 is located in or on the dialysate drain line 31b.

[0086] The valve V28 is located in a dialysate drain line 31b.

[0087] The valve V31 is located in the first fluid guide 3 of the automatic substituate connector 18b or in a line leading to it.

[0088] The valve V32 is located in the second fluid guide 5 of the automatic substituate connector 18b or in a line leading to it.

[0089] The valve V33 is located in the drain line 45.

[0090] Valve V19 is located downstream of all the above-mentioned valves V24, V25, V28, V31, V32 and V33.

[0091] Also shown is an ultrafiltration pump P03. A hydraulic balancing chamber 40 is only indicated.

[0092] A control or regulating device 28 according to the invention for controlling or regulating the blood treatment device 4 is provided and can be in signal and / or control connection with all of the above-mentioned components of the blood treatment device 4.

[0093] In the prior art, the extracorporeally pumped patient blood during a single-needle treatment is typically temporarily parked in a compliance chamber of the extracorporeal tubing system before or after its purification in the blood treatment device, thus enabling alternating pumping. In the first of the two alternating phases, the patient blood is pumped through one access point into the blood-side compliance chamber by means of the blood pump 11, whereby the purification process is not yet complete or has already been completed. In the second phase, the blood is pumped back to the patient from the compliance chamber (usually by means of an actuator or pump in addition to the blood pump 11). This actuator can be a second pump or a compressor, e.g., for air. The volume of the compliance chamber corresponds to the single-needle stroke volume and is generally between 25 and 100 ml, occasionally between 30 and 60 ml.Such a conventional blood-side compliance chamber of the extracorporeal tubing system or blood tubing set is neither required nor provided according to the invention.

[0094] What Fig. 1 Not shown is the optional embodiment, also according to the invention, in which a single-needle chamber or compliance chamber is provided on the hydraulic side, as part of the hydraulic system or on the side of the blood treatment device 4 (i.e. not in the blood tubing set 1 or not physically connected thereto). Such a single-needle chamber or compliance chamber would be related to the representation of the Fig. 1 i.e. to the left of the blood filter 19, at least to the left of the semi-permeable membrane 19c.

[0095] Fig. 2a shows, by way of example, in a graphic representation, the schematic structure of the blood tubing set 1 during the first phase, designated above with a), of the method disclosed herein.

[0096] The basis of Fig. 2a The method described utilizes the volume of the dialysis fluid chamber 19b and, if applicable, the hydraulic lines of the blood treatment device 4 connected thereto to collect liquid portions of blood, preferably followed by discarding them into a sink, a bag, or the like. The connected lines can be the dialysis fluid supply line 31a and / or the dialysate drain line 31b.

[0097] According to the invention, rather than whole blood being pumped through the semi-permeable membrane 19c into the hydraulic system and discarded therethrough, plasma water is pumped. This can be discarded as effluent or filtrate (e.g., into the sink). During the transfer of plasma water to the hydraulic system, which occurs in the first phase (referred to above as step a)), the blood is hemoconcentrated in the blood chamber 19a of the blood filter 19. The plasma water is displaced across the semi-permeable membrane 19c of the blood filter 19 by building up an increased pressure in the blood chamber 19a when the venous hose clamp 7 is closed and the blood pump 11 is pumping toward the blood filter 19. This pressure is higher than that prevailing in the dialysis fluid chamber 19b, i.e., on the dialysis fluid side of the blood filter 19. The resulting fluid flows across the membrane 19c are indicated by arrows.They are further indicated by arrows in parentheses on lines 31a and 31b. The parentheses indicate that one or more of the flows indicated by the arrows in parentheses are not necessarily required, but can optionally occur.

[0098] The blood pump 11 is obviously pumping, causing blood flow in the access device 89 and in the arterial blood line 8 toward the blood filter 19. The venous tube clamp 7 is closed, which is indicated by an "X" next to the tube clamp 7. In the venous blood line 9, which connects downstream to the blood filter 19, no blood flows because the tube clamp 7 is closed.

[0099] Corpuscular components that cannot overcome the semi-permeable membrane 19c remain on the blood side of the blood filter 19, i.e. on the side of the blood chamber 19a, which leads to the above-mentioned concentration there.

[0100] It is evident that the Fig. 2a The blood tubing set 1 used does not have a blood-side single-needle chamber. However, it is connected to a blood filter 19 and is used for single-needle treatment.

[0101] The one in the Fig. 2a The transfer of fluid across the semi-permeable membrane 19c, i.e., from the blood chamber 19a into the dialysis fluid chamber 19b, which takes place in the phase shown, can be referred to as "positive ultrafiltration." It can be accompanied, at least in phases, by an accepted imbalance. The imbalance can, for example, result from fluid from the hydraulic side or dialysis side (i.e., to the right of the semi-permeable membrane 19c in Fig. 2a ) is discarded, e.g., into a sink, e.g., via the Fig. 1 shown drain line 45.

[0102] Fig. 2b shows in the representation of the Fig. 2a Example of blood line set 1 during the second phase of the procedure.

[0103] In the second phase (referred to above as step b), a volume of fluid, optionally quantitatively equivalent to the volume previously displaced across the semi-permeable membrane 19c, is forced across the semi-permeable membrane 19c and into the blood tubing set 1. The fluid displaced in step b) is usually fresh dialysis fluid or substituate solution, which may originate from a bag or be produced by the blood treatment device. The volume on the blood side of the blood filter 19 is optionally approximately 100-150 ml.

[0104] The flow conditions reverse in step b), measured against those for Fig. 2a described, essentially.

[0105] The blood pump 11 can be stationary. If it is an occlusion pump, as optionally shown in the figures, it prevents blood from flowing back into the arterial blood line 8 in its resting state. Since it is stationary or at rest, it does not increase the pressure downstream of the blood pump 11.

[0106] Instead of or in addition to a possible occlusion effect of the blood pump 11, a Fig. 2a and 2b An arterial tube clamp (not shown) may be provided. It can be used in the Fig. 2b The illustrated phase prevents blood from flowing along the arterial blood line 8 away from the blood filter 19 and towards the patient. The arterial tube clamp may be the one with reference number 6 of Fig. 1 It may be a different hose clamp and / or located at a different location in the arterial blood line 8.

[0107] The pumping action, which leads to Fig. 2b indicated transfer of fluid across the semi-permeable membrane 19c, can be determined from the Fig. 2b not shown ultrafiltration pump P03 or any other pump on the dialysis or hydraulic side, such as a dialysis fluid pump.

[0108] Fig. 2c shows in the representation of the Fig. 2a and the Fig. 2b by way of example, the blood line set 1 during the optional third phase of the procedure, which is provided between the first and second phases.

[0109] In the third or interim phase (referred to above as step c), no or essentially no fluid volume is displaced across the semi-permeable membrane 19c. Rather, in step c), fluid, usually fresh dialysis fluid or substitution solution, for example, prepared from a bag or by the blood treatment device, is guided along the semi-permeable membrane 19c through the dialysis fluid chamber 19b.

[0110] The blood pump 11 can be stationary. If it is an occlusion pump, as optionally shown in the figures, it prevents blood from flowing back into the arterial blood line 8 in its resting state.

[0111] Instead of or in addition to a possible occlusion effect of the blood pump 11, a Fig. 2a , 2b and 2c An arterial tube clamp (not shown) may be provided. It can be used in the Fig. 2c The illustrated phase prevents blood from flowing along the arterial blood line 8 away from the blood filter 19 and towards the patient. The arterial tube clamp may be the one with reference number 6 of Fig. 1 It may be a different hose clamp and / or located at a different location in the arterial blood line 8.

[0112] The resulting fluid flows are indicated by arrows along the membrane 19c. They are also indicated by arrows along the lines 31a and 31b.

[0113] As explained above, the blood pump 11 does not pump during this third phase (interim phase), so that no blood flows through the access device 89 and the arterial blood line 8 toward the blood filter 19. The venous tube clamp 7 is closed, which is again indicated by an "X" next to the tube clamp 7. In the venous blood line 9, which connects downstream to the blood filter 19, no blood flows either, due to the closed tube clamp 7.

[0114] Corpuscular components that cannot overcome the semi-permeable membrane 19c remain on the blood side of the blood filter 19, i.e. on the side of the blood chamber 19a, in this interim phase, but diffusion of membrane-permeable substances does occur due to the osmotic pressure between the blood chamber 19a and the dialysis fluid chamber 19b, which is further increased by the above-mentioned hemoconcentration.

[0115] The one in the Fig. 2c The transfer taking place in the phase shown solely by means of diffusion across the semi-permeable membrane 19c, i.e. from the blood chamber 19a into the dialysis fluid chamber 19b, can be referred to as "dialysis" or "hemodialysis".

[0116] The pumping action, which leads to Fig. 2c indicated flow of fluid along, but not across, the semi-permeable membrane 19c, can be determined from the Fig. 2c not shown ultrafiltration pump P03 or any other pump on the dialysis or hydraulic side (such as a two-chamber dosing pump, the chambers of which, as above, alternately provide the chamber volume according to the above-mentioned phases for filtration or substitution), for example by a dialysis fluid pump.

[0117] A combination of the above steps a) and c) or b) and c) is not shown in the figures. For such combinations, the Fig. 2a and 2c or 2b and 2c, respectively, are present together.

[0118] The following explanations explain more concrete, exemplary configurations or embodiments of the method.

[0119] According to the inventors, the blood volume in the blood filter 19 can be concentrated by up to 33% (f=0.33). For a blood filter volume V DB of, for example, 120 ml, the maximum possible stroke volume V s is thus calculated as: V S = V DB ⋅ f 1 − f = 120 ml ⋅ 0,33 1 − 0,33 = 60 ml

[0120] Proof of equation 1 (analogous to the geometric series): A volume f* V DB displaced from the blood chamber 19a is returned, preferably using fresh substitution solution, to the bloodstream 1. Subsequently, a volume f* f* V DB is again displaced and optionally discarded, which is then refilled or replaced with fresh fluid (i.e., fluid that has not yet come into contact with blood), and so on: V S = V DB ⋅ f + f 2 + f 3 + ⋯ = f ⋅ V DB ⋅ ∑ n = 0 f n

[0121] Transformations provide the following for the above expression: ∑ n = 0 f n = 1 1 − f , f < 1 and for the stroke volume V s : V S = f ⋅ V DB ⋅ ∑ n = 0 f n = V DB ⋅ f 1 − f

[0122] In detail, the following two repetitive procedural steps 1) and 2) are necessary to treat with single-needle therapy: 1) Using the blood pump, with the venous tube clamp 7 closed ( Fig. 2a ) Patient blood is pumped into the blood filter 19, while in the present example approximately 33% of the blood volume is concentrated in the blood filter 19 by filtering out plasma water across the semi-permeable membrane 19c into the hydraulic part.

[0123] Filtration occurs either via active hydraulic-side ultrafiltration, e.g., by means of the ultrafiltration pump P03, or without the use of pumps on the hydraulic side (dialysis side) by volume displacement during the reduction of the increase in pressure in the blood chamber 19a of the blood filter 19 generated by the blood pump 11.

[0124] The maximum volume to be displaced VS ("stroke volume") depends on the size of the blood-side volume V DB of the blood chamber 19a of the blood filter 19 and the concentration f depends on and is calculated according to: V S = V DB ⋅ f 1 − f

[0125] The hemoconcentration in the blood filter 19 leads to a decrease in the permeability of the semi-permeable membrane 19c, which results in an increase in the pressure in the blood chamber 19a. This pressure can be measured via a pressure sensor between the blood pump 11 and the blood filter 19, e.g., the prefilter pressure sensor 33c, or estimated based on the electrical power consumption of the blood pump 11. The measured pressure, regardless of where it is measured, can be used to control the method; the devices according to the invention can be configured accordingly. The pressure can additionally or alternatively, particularly when the venous tube clamp 7 is closed, also be measured at the venous pressure sensor 33b downstream of the blood filter 19.

[0126] Another possibility for feedback is the analysis of the pressure pulses generated by the peristaltic blood pump 11, which can be measured, for example, using the hydraulic-side pressure sensor 37. As the membrane permeability decreases, the pressure signal received at the hydraulic pressure sensor 37 decreases.

[0127] When a predetermined pressure value is reached in the blood chamber 19a, the blood pump 11 is stopped and the venous tube clamp 7 is opened, while volume is pumped back into the blood tube set 1 via the semi-permeable membrane 19c by means of excess pressure in the hydraulic part.

[0128] The recovered volume flows back toward the patient along the venous blood line 9. The volumes transported across the semi-permeable membrane 19c are optionally balanced. The cleaning effect in the blood filter 19 is achieved partly by diffusive transport processes in the presence of dialysis fluid or dialysate flow and partly by the convective transport of the plasma water to be displaced.

[0129] The stroke volumes that can be achieved on request according to equation (1) are comparable to typical volumes in standard single-needle therapies.

[0130] The one in the Fig. 2b The transfer of fluid across the semi-permeable membrane 19c, i.e. from the dialysis fluid chamber 19b into the blood chamber 19a, can be referred to as "negative ultrafiltration". It can be used to compensate for the Fig. 2a In some embodiments, the imbalance, which is accepted at least in phases in the phase shown, can be supported, for example, by means of substitution administration on the hydraulic side. The imbalance, which may have resulted, for example, from fluid from the hydraulic side or dialysis side (i.e., to the right of the semi-permeable membrane 19c in Fig. 2a ) has been rejected, can be corrected or compensated.

[0131] The miscalculation that occurred in Fig. 2a shown phase, and which in the in Fig. 2b The phase shown can be deliberately desired and its size can be optionally predetermined. Bezugszeichenliste

[0132] 1Extracorporeal blood circuit, blood tubing set 2Blood cassette 3First fluid guide of the automatic substituate connector 18b 4Blood treatment device 5Second fluid guide of the automatic substituate connector 18b 6Arterial tube clamp 7Venous tube clamp 8Arterial blood line 9Venous blood line 10Access device 11Blood pump 13Addition point for substituate fluid (pre-dilution) 14Addition point for substituate fluid (post-dilution) 15Arterial air-blood detector 17Substituate pump 18aAutomatic substituate port 18bAutomatic substituate connector 19Blood filter 19aBlood chamber 19bDialysis fluid chamber 19cSemi-permeable membrane 21Venous air separation chamber 23Check valve of the Substituate channel 25 Venous air-blood detector or air-substituate fluid-blood detector 26 Compressed air source 28 Control device, control and / or regulating device 31a Dialysis fluid inlet line 31b Dialysate outlet line 33a,bPressure sensors 33cPrefilter pressure sensor 35Y-shaped connector 37Pressure sensor 40Hydraulic balance chamber 45Drain line 89Patient hose line V19Valve of the dialysate drain line 31b V22Valve V24Valve of the dialysis fluid supply line 31a V25Valve of the dialysate drain line 31b V26Valve V28Valve of the dialysate drain line 31b V31Valve of the first fluid line 3 of the automatic substituate connector 18b V32Valve of the second fluid line 5 of the automatic substituate connector 18b V33First valve of the drain line 45 P03Ultrafiltration pump,

Claims

1. A control device (28) for controlling or regulating a blood treatment apparatus (4) for treating blood by means of a single-needle method, wherein the blood treatment apparatus (4) to be controlled or regulated comprises: - a blood pump (11), connectable to a blood hose set (1) for conveying blood through the blood hose set (1), wherein the blood pump (11) is operable in a withdrawal direction; - a return pump, arranged to convey fluid towards the blood hose set (1) or a portion thereof and / or towards the patient in a return direction during use of the blood treatment device (4); wherein the control device (28) is configured, to perform a method by means of the blood treatment apparatus (4), the method encompassing the following steps: a) operating the blood pump (11) in a withdrawal direction, in which blood is withdrawn from the patient blood circuit and pumped along a patient hose line (89) into the blood hose set (1), into which a blood filter (19) with a blood chamber (19a) and a dialysis liquid chamber (19b) is integrated, the blood chamber (19a) and the dialysis liquid chamber (19b) being separated from one another by a semi-permeable membrane (19c); and b) operating the return pump such that blood is pumped out of the blood hose set (1) and pumped along the patient hose line (89) back into the patient blood circuit; wherein steps a) and b) are carried out alternately several times; wherein the method further comprises the following step: - controlling and / or monitoring the method by or under analysis of the pressure measurement values and / or the motor electricity consumption of at least one pump; characterized in that, that blood is not stored in a blood-side single-needle chamber between its withdrawal in step a) and its return in step b).

2. The control device (28) according to claim 1, wherein the method further comprises: - closing a venous hose clamp (7) during or before blood is conveyed from the patient towards the blood filter (19) in step a); - effecting the passage of plasma water of the conveyed blood via the semi-permeable membrane (19c) of the blood filter (19) by establishing a pressure difference between the dialysis liquid chamber (19b) and the blood chamber (19a); - opening the venous hose clamp (7); - effecting the passage of liquid from the dialysis liquid chamber (19b) via the semi-permeable membrane (19c) into the blood chamber (19a) of the blood filter (19) by establishing a suitable pressure on the hydraulic side, while in step b) blood is being pumped back into the patient blood circuit along the patient hose line (89).

3. The control device (28) according to claim 1 or 2, wherein the blood hose set (1) comprises: - a patient hose line (89) for both the withdrawal of blood from the patient blood circuit into the blood hose set (1) and its return from the blood hose set (1) into the patient blood circuit; - a Y-shaped connector (35) or three-way connector connected to the patient hose line (89); wherein the blood hose set (1) does not have a blood-side single-needle chamber or is not connected to a blood-side single-needle chamber.

4. A blood treatment apparatus (4) for performing a single-needle blood treatment, wherein the blood treatment apparatus (4) comprises: - a blood pump (11), connectable to a blood hose set (1) for conveying blood through the blood hose set (1), wherein the blood pump (11) is operable in a withdrawal direction; - a return pump, arranged to convey fluid towards the blood hose set (1) or a portion thereof and / or towards the patient in a return direction during use of the blood treatment device (4); - a control device (28), configured for controlling or regulating the blood treatment apparatus (4); wherein the control device (28) is programmed to perform a single-needle treatment by means of a method comprising the following steps: a) operating the blood pump (11) in a withdrawal direction, in which blood is withdrawn from the patient blood circuit and pumped into the blood hose set (1), into which a blood filter (19) with a blood chamber (19a) and a dialysis liquid chamber (19b) is integrated, the blood chamber (19a) and the dialysis liquid chamber (19b) being separated from one another by a semi-permeable membrane (19c); and b) operating the return pump such that blood is pumped out of the blood hose set (1) and pumped back into the patient blood circuit; wherein the method further comprises the following step: - controlling and / or monitoring the method by or under analysis of the pressure measurement values and / or the motor electricity consumption of at least one pump; characterized in that, that blood is not stored in a blood-side single-needle chamber between its withdrawal in step a) and its return in step b).

5. A blood treatment apparatus (4) according to claim 4, embodied as a hemodialysis apparatus, hemofiltration apparatus or as a hemodiafiltration apparatus, in particular as an apparatus for chronic renal replacement therapy or for continuous renal replacement therapy (CRRT = continuous renal replacement therapy).

6. The blood treatment apparatus (4) according to anyone of the claims 4 or 5, wherein the blood hose set (1) comprises: - a patient hose line (89) for both the withdrawal of blood from the patient blood circuit into the blood hose set (1) and its return from the blood hose set (1) into the patient blood circuit; - a Y-shaped connector (35) or three-way connector connected to the patient hose line (89); wherein the blood hose set (1) does not have a blood-side single-needle chamber or is not connected to a blood-side single-needle chamber.