Extracorporeal blood treatment machine, computer-implemented detection method and computer program

Abstract

The present disclosure relates to an extracorporeal blood treatment machine for extracorporeal blood treatment of a patient, the invention relates to an extracorporeal blood dialysis device, comprising a dialyzer, an extracorporeal blood circuit comprising an arterial section and a venous section, a dialysate circuit, a blood characteristic detection unit and / or a dialysate characteristic detection unit, and a control unit which is in signal connection with the blood characteristic detection unit and / or the dialysate characteristic detection unit. The blood treatment machine is arranged to, upon preparation of the extracorporeal blood treatment: perform pre-charging of the extracorporeal blood circuit with a priming fluid; requesting and / or determining a coupling of an arterial shunt section to an arterial section filled with a priming fluid by said pre-charging; requesting and / or determining a coupling of a venous shunt section to a venous section filled with a priming fluid by said pre-charging; and detecting and / or quantifying and / or checking the recirculation and / or recirculation rate at the shunt at least on the basis of the blood properties and / or dialysate properties detected after the joining of the venous shunt section.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an extracorporeal blood treatment machine, in particular a dialysis machine, for extracorporeal blood treatment such as hemodialysis, hemofiltration, hemodiafiltration and / or ultrafiltration, to a computer-implemented detection method for detecting recirculation at a shunt of an extracorporeal blood circuit of a blood treatment machine, and to a computer program. The extracorporeal blood treatment machine has a dialyzer with a semipermeable membrane for exchanging substances between patient blood conveyed in an extracorporeal blood circuit and dialysis fluid conveyed in a dialysis fluid circuit. The extracorporeal blood circuit has an arterial segment arranged for coupling to an arterial shunt segment of a shunt of a patient and a venous segment arranged for coupling to a venous shunt segment. BACKGROUND

[0002] In extracorporeal blood treatment, for example blood purification in the form of hemodialysis, hemofiltration or hemodiafiltration, blood is taken from a dialysis patient via an arterial blood vessel access and is conveyed via an extracorporeal blood circuit to a dialyzer for blood treatment. In addition, dialysis fluid is supplied to the dialyzer by a separate dialysis fluid circuit. In the dialyzer, the blood of the blood circuit and the dialysis fluid of the dialysis fluid circuit are brought into contact by means of a semipermeable membrane, so that an exchange of substances between the blood and the dialysis fluid takes place. Thus, in the case of dialysis treatment of a patient with insufficient kidney function, harmful substances in the blood as well as excess water, for example excess water that has accumulated in the body as a result of underlying kidney failure, can be removed. The blood thus purified is then returned to the patient again via a venous blood vessel access.

[0003] It is highly important in extracorporeal blood treatment that the arterial and venous cannulae are properly spaced apart at the shunt of the patient, so that they properly puncture the shunt and the shunt is not constricted, because otherwise recirculation from the venous shunt segment to the arterial shunt segment can occur. Recirculation means that blood that has already been purified does not partially flow back into the vein and thus into the body, but instead directly overflows into the arterial shunt segment and is conveyed from there directly back to the dialyzer, bypassing the body. Recirculation thus reduces the efficiency of the blood treatment and leads to an extension of the treatment duration. It is therefore very important to identify current recirculation and to take measures to eliminate the recirculation.

[0004] The publication DE 10 2021 116 343 A1 discloses a recirculation measurement by means of two intermittent switches with kinetically different diffusion states.

[0005] The publication EP 2 783 713 A1 discloses a further method for detecting recirculation at a shunt. To this end, a property of the dialysate is detected at a dialysate output of the dialyzer, which property is related to a blood property of the extracorporeal blood circuit. From a change curve of the dialysate property detected at the dialysate output, a possible presence of recirculation is inferred by means of a bolus administration on the blood side during dialysis.

[0006] The disadvantage of the method according to the prior art is that a defined bolus administration and / or blood sample withdrawal together with an analysis are required. SUMMARY

[0007] The task of the present disclosure is, in contrast, to avoid or at least reduce the disadvantages in the prior art and to provide an extracorporeal blood treatment machine, a computer-implemented detection method and a computer program by means of which a more efficient and safer extracorporeal blood treatment is provided.

[0008] The task of the present disclosure is solved with respect to an extracorporeal blood treatment machine, with respect to a computer-implemented detection method and with respect to a computer program according to the invention.

[0009] The basic idea of the present disclosure provides for providing an extracorporeal blood treatment machine which is set up to examine a patient's shunt with respect to recirculation on the shunt in the preparation phase of an extracorporeal blood treatment, in particular dialysis, i.e. before or at the start of the extracorporeal blood treatment, according to the principle of a liquid bolus administration.

[0010] A further basic idea of the present disclosure is to provide a computer-implemented detection method which is implemented in particular as a computer program in a control unit of an extracorporeal blood treatment machine, whereby the blood treatment machine is set up to examine a patient's shunt with respect to recirculation at the shunt in the preparation phase of an extracorporeal blood treatment, in particular dialysis, according to the principle of a liquid bolus administration.

[0011] According to the present disclosure, the basic idea is implemented in that a liquid bolus is formed from a priming liquid which is originally used for the priming of the extracorporeal blood circuit of the blood treatment machine in the preparation phase of the extracorporeal blood treatment and which is at least in portions transfused to the patient after its venous connection. The examination of the recirculation at the shunt thus takes place directly after the priming / flushing by means of the priming liquid used to this end as liquid bolus.

[0012] In other words, the extracorporeal blood treatment machine according to the present disclosure, the detection method according to the present disclosure and the computer program according to the present disclosure respectively provide that the priming liquid is used not only for the priming / flushing but also for the detection of the recirculation and that the point in time of the transfusion is set to the end of the priming / flushing, i.e. to before the start of the extracorporeal blood treatment or to the transition period between the priming / flushing and the extracorporeal blood treatment.

[0013] In this way, the pre-filling / flushing of the extracorporeal blood circuit, which would otherwise be carried out, is used according to the present disclosure for the early identification of a possible recirculation, i.e. before or at the beginning of the treatment / extracorporeal blood treatment / dialysis treatment. It is thus ensured that the correct cannulation at the shunt is present before or at the beginning, which makes the following treatment / extracorporeal blood treatment / dialysis treatment more efficient and safer. In particular, it is thereby ensured that the correct cannulation at the shunt does not have to be further checked or changed during the further course of the treatment / extracorporeal blood treatment / dialysis treatment by medical personnel.

[0014] The extracorporeal blood treatment machine, in particular dialysis machine, in particular hemodialysis machine, according to the present disclosure is provided for the extracorporeal blood treatment of a patient's blood and has at least:

[0015] - a dialyzer having a semipermeable membrane;

[0016] - an extracorporeal blood circuit having a blood pump adapted to convey fluid, in particular blood, through the dialyzer, wherein the extracorporeal blood circuit extends from an arterial section, which is provided for joining an arterial shunt section, through a blood input of the dialyzer, through the dialyzer on the blood side of the semipermeable membrane, through a blood output of the dialyzer and to a venous section, which is provided for joining a venous shunt section;

[0017] - a dialysate circuit adapted to provide fresh dialysate, to convey the fresh dialysate through the dialyzer and to discharge used dialysate or dialysate, and which extends from a dialysate supply of the blood treatment machine to a dialysate input of the dialyzer, through the dialyzer on the dialysate side of the semipermeable membrane to a dialysate output of the dialyzer and to a dialysate tank of the blood treatment machine;

[0018] - a (first) blood property detection unit adapted to detect a blood property in the extracorporeal blood circuit, in particular at the arterial section, and / or a (third) dialysate property detection unit adapted to detect a dialysate property at the dialysate outlet; and

[0019] - a control unit in signal connection with the (first) blood property detection unit and / or the (third) dialysate property detection unit.

[0020] According to the present disclosure, the blood treatment machine is provided to, when preparing the extracorporeal blood treatment:

[0021] - the pre-filling or rinsing of the extracorporeal blood circuit with priming fluid from the arterial section to the venous section is performed, preferably by manipulating the blood pump by means of the control unit;

[0022] - the coupling of the arterial shunt section to the arterial section filled by pre-filling or rinsing with priming fluid is requested by an operator, in particular by a medical staff member or the patient himself (in the case of home dialysis), preferably by manipulating an output or display unit of the blood treatment machine by means of the control unit and / or determined based on sensor signals or input signals, in particular,

[0023] - the coupling of the venous shunt section to the venous section filled with priming fluid by rinsing is requested by an operator, preferably by manipulating an output or display unit of the blood treatment machine by means of the control unit and / or determined based on sensor signals or input signals, and

[0024] - the recirculation and / or recirculation rate at the shunt is detected and / or quantified and / or checked, preferably by means of the control unit, at least in accordance with the blood properties and / or dialysate properties detected after the coupling of the venous shunt section.

[0025] According to the present disclosure, the blood treatment machine is preferably provided, preferably by means of the control unit, to additionally detect and / or quantify and / or check the recirculation and / or recirculation rate at the shunt in accordance with the blood delivery rate or blood flow and / or dialysate flow and / or dialyzer or dialyzer type.

[0026] According to the present disclosure, the extracorporeal blood treatment machine has according to a first variant a (first) blood property detection unit which is adapted to detect blood properties in the extracorporeal blood circuit, in particular at the arterial section, the control unit is in signal connection with the (first) blood property detection unit, and the blood treatment machine, in particular the control unit, is provided to detect and / or quantify and / or check the recirculation and / or recirculation rate at the shunt in accordance with the blood properties detected after the coupling of the venous shunt section.

[0027] According to the present disclosure, the extracorporeal blood treatment machine has according to a second variant a (third) dialysate property detection unit which is adapted to detect dialysate properties at the dialysate outlet, the control unit is in signal connection with the (third) dialysate property detection unit, and the blood treatment machine, in particular the control unit, is provided to detect and / or quantify and / or check the recirculation and / or recirculation rate at the shunt in accordance with the dialysate properties detected after the coupling of the venous shunt section.

[0028] According to the disclosure, the extracorporeal blood treatment machine according to the third variant not only has a (first) blood property detection unit which is adapted to detect a blood property in the extracorporeal blood circuit, in particular at the arterial section, but also a (third) dialysate property detection unit which is adapted to detect a dialysate property at the dialysate outlet, the control unit is in signal connection not only with the (first) blood property detection unit but also with the (third) dialysate property detection unit, and the blood treatment machine, in particular the control unit, is set up to detect and / or quantify and / or check recirculation at the shunt and / or the recirculation rate from the blood property detected after the connection of the venous shunt section and from the dialysate property detected after the connection of the venous shunt section. Here, the third variant is particularly advantageous, since it enables the combination and checking of the measurement values obtained on the blood side and on the dialysate side.

[0029] According to the disclosure, therefore, the blood treatment machine is set up to use the priming fluid which would otherwise be used for priming before the blood treatment or before the treatment as the liquid mass for detecting recirculation. That is to say, no additional or external mass dosing is required. According to the disclosure, therefore, an evaluation of the recirculation of the shunt, i.e. an evaluation of the cannula fit and / or the shunt status, is achieved before the start of the blood treatment / treatment or at the start of the blood treatment / treatment. This has the advantage that the subsequent blood treatment or treatment does not have to be interrupted in order to detect the recirculation. Since the recirculation can already be detected in the preparation phase of the blood treatment / treatment and remedial measures can be taken according to the disclosure, a more efficient and safe extracorporeal blood treatment / treatment is possible.

[0030] Since the (first) blood property detection unit, which is preferably arranged on the arterial section of the extracorporeal blood circuit, is anyway mostly set up in an integrated machine, the device-technical outlay for carrying out the method according to the disclosure is small or no retrofitting or supplementing of the extracorporeal blood treatment machine is required, in addition to the first variant described above and the third variant described above.

[0031] According to the improvement, the control unit is set up to detect the recirculation at the shunt at least from the deviation of the blood property detected after the connection of the venous shunt section from a reference blood property without recirculation, and / or from the value ratio of the blood property detected after the connection of the venous shunt section to a reference blood property without recirculation, and / or from the extreme value or saddle point of the blood property detected after the connection of the venous shunt section, and / or from the gradient of the blood property detected after the connection of the venous shunt section, and preferably outputs, in particular acoustically and / or visually and / or haptically, a message about the detected recirculation.

[0032] According to an improvement, the control unit is set up to quantify the recirculation rate at the shunt at least from the deviation and / or the value ratio and / or the gradient and preferably to output, in particular acoustically and / or visually and / or haptically, a message about the detected recirculation rate.

[0033] According to an improvement, the control unit is set up to determine the deviation as a difference or ratio of the detected blood properties at different points in time or as a differential area between the detected blood property after the connection of the venous shunt section and a reference blood property without recirculation.

[0034] According to an improvement, the control unit is set up to store (in a storage unit) the detected blood property, in particular a time profile thereof, at the arterial section at the latest when the connection of the venous section is determined.

[0035] According to an improvement, the control unit is set up to store the blood property at least at a first point in time and a second point in time and to perform the detection and / or the quantification by means of the blood property.

[0036] In a first variant, the connection of the arterial shunt section is first carried out, then the delivery by means of the blood pump or instead of the pump, and only then the connection of the venous shunt section. In this case, the first point in time is the point in time at which the undiluted blood flows through the blood property detection unit, and the second point in time is the point in time at which the blood diluted with the priming fluid flows through the blood property detection unit in the event of recirculation.

[0037] In a second variant, however, the connection of the arterial shunt section and the venous shunt section is carried out at the same stop of the blood pump. In this case, the first point in time is the point in time at which the diluted blood flows through the blood property detection unit, and the second point in time is the point in time at which the blood, which is less diluted with the priming fluid, in particular undiluted, flows through the blood property detection unit in the event of recirculation.

[0038] According to an improvement, the control unit is set up to receive a detected or input positive interruption criterion for the priming / flushing.

[0039] In particular, for this purpose, a second detection unit and / or an input interface, for example a touchscreen, is provided and configured at least for detecting air or bubbles, preferably in or at the venous section.

[0040] Preferably, the second detection unit has, in addition to the detector or sensor for detecting air or bubbles, a detector or sensor for detecting red color or blood.

[0041] Preferably, the probe / sensor for detecting air or air bubbles and red color or blood is accommodated in the same sensor housing of the second detection unit.

[0042] Preferably, the positive interruption criterion is the absence of air bubbles in the extracorporeal blood circuit.

[0043] According to an improvement, the control unit is set to stop the blood pump after receiving the positive interruption criterion and to output a requirement for coupling the venous shunt section and / or the arterial shunt section, in particular to an operator.

[0044] In the case of the first variant described above, in which the arterial and venous coupling is carried out sequentially, the coupling of the arterial shunt section is carried out first after receiving the positive interruption criterion "absence of air bubbles". Blood withdrawal and blood delivery from the arterial section to the venous section are then carried out until red color or blood is detected by the second detection unit and the blood pump or the replacement pump is stopped by the control unit. The requirement for coupling the venous shunt section is fulfilled. After the coupling of the venous shunt section has been determined or input, blood withdrawal and blood delivery continue.

[0045] In the case of the second variant described above, the arterial coupling and the venous coupling are carried out in parallel, i.e. concurrently, at the same stop of the blood pump or the replacement pump, after receiving the positive interruption criterion "absence of air bubbles".

[0046] According to an improvement, the control unit is set to stop the blood pump with a time delay after receiving the positive interruption criterion in order to ensure the absence of air bubbles in the hose section extending downstream of the second detection unit for detecting air or air bubbles, and to output a requirement for coupling the venous shunt section or the arterial shunt section or for coupling the arterial shunt section and the venous shunt section to an operator only after the time delay has ended.

[0047] According to an improvement, the control unit is set to determine the time delay as a function of the detected or determined blood delivery rate and the volume of the hose section.

[0048] Alternatively or additionally, the control unit is provided with a fixed time delay.

[0049] According to an improvement, the control unit is set to output a requirement for coupling the venous shunt section and the arterial shunt section during the same interruption of the priming / flushing, in particular after receiving the positive interruption criterion.

[0050] According to the refinement, the control unit is set up to output the requirement for the connection of the arterial shunt section first after receiving the positive interruption criterion and, upon determination of the connection of the arterial shunt section, to control the delivery of the drain fluid via the venous shunt section into the waste container or line by operating the blood pump, so that the connection of the venous shunt section with the later interruption of the rinsing is thus achieved. The waste container or the waste line can be configured, for example, as a bag or a container or as a waste port or a removal line.

[0051] According to the refinement, the control unit is set up to receive a signal from the blood of the detection on the venous section of a second detection unit of the blood treatment machine, to stop the blood pump and to output the requirement for the connection of the venous shunt section.

[0052] Preferably, the blood treatment machine has an acoustic and / or visual and / or haptic display or output unit, in particular a screen, for outputting in particular the aforementioned requirements and for detecting and / or quantifying the recirculation and / or the recirculation rate.

[0053] According to the second variant described above or the third variant described above, the extracorporeal blood treatment machine has:

[0054] a (third) dialysate property detection unit, which is signal-connected to the control unit and is set up to detect a dialysate property at the dialysate outlet. According to the present disclosure, the control unit according to these variants is set up to detect and / or quantify and / or check the recirculation and / or the recirculation rate on the basis of the detected dialysate property after the connection of the venous shunt section.

[0055] The detection of the recirculation and / or the quantification of the recirculation rate can thus take place in a redundant manner. On the one hand by means of the first blood property detection unit on the blood side and on the other hand by means of the third dialysate property detection unit on the dialysate side.

[0056] According to the present disclosure, it is thus possible to reliably check the fit of the cannula on the shunt and / or the state of the shunt by means of both detected properties, since the detection and / or the quantification can take place not only unilaterally by means of the detected blood property or the detected dialysate property, but also bilaterally, i.e. by means of the detected blood property and the detected dialysate property.

[0057] Preferably, the control unit is set up to form an average value from the recirculation rates quantified on the blood side and on the dialysate side, in order thus to increase the measurement accuracy and / or the statement reliability with regard to the recirculation that can be present. The averaging can be realized, for example, with different weightings of the two recirculation rates.

[0058] Preferably, the control unit is arranged to check the plausibility of the recirculation rates quantified on the blood side and on the dialysate side. If both recirculation rates are approximately the same, the recirculation rates determined can be relied on. If these recirculation rates differ, the control unit is preferably arranged to output a prompt about this.

[0059] According to the refinement, the control unit is arranged to detect and / or quantify and / or check the recirculation at the shunt and / or the recirculation rate at the shunt depending on the deviation of the dialysate property detected after the connection of the venous shunt section from the reference dialysate property without recirculation and / or the value ratio of the dialysate property detected after the connection of the venous shunt section from the reference dialysate property without recirculation and / or depending on the gradient of the dialysate property detected after the connection of the venous shunt section.

[0060] According to the disclosure, the blood treatment machine described above is arranged to carry out each step of the computer-implemented detection method described below. If one of the steps is carried out / manually has to be carried out, for example by an operator, in particular by a medical operator or the patient himself, for example the respective connection of the shunt, the blood treatment machine is preferably arranged to output an acoustic and / or visual and / or haptic request or message which prompts the operator to carry out the manual step.

[0061] Preferably, the control unit of the blood treatment machine has a storage unit in which the detection method according to at least one aspect of the disclosure disclosed below and / or the computer program according to at least one aspect of the disclosure disclosed below is stored for implementation.

[0062] Preferably, the blood treatment machine is arranged to carry out the detection method in the preparation of the extracorporeal blood treatment and to end the detection method before or at the start of the extracorporeal blood treatment or therapy.

[0063] According to the disclosure, a computer-implemented detection method for detecting / determining the recirculation at a shunt of an extracorporeal blood circuit of a blood treatment machine in the preparation of an extracorporeal blood treatment is provided. The blood treatment machine has a dialyzer with a semipermeable membrane on which blood conveyed in the extracorporeal blood circuit can exchange substances with dialysate of a dialysate circuit. According to the disclosure, the method has the steps:

[0064] - pre-charging / flushing (hereinafter only referred to as flushing) of the extracorporeal blood circuit from an arterial section of the extracorporeal blood circuit arranged for connection with an arterial shunt section with a priming fluid to a venous section of the extracorporeal blood circuit arranged for connection with a venous shunt section. The pre-charging / flushing can take place by means of gravity and / or by means of a blood pump of the blood treatment machine or instead of a pump;

[0065] - requesting and / or determining a connection of the arterial shunt section to the extracorporeal blood circuit with an arterial section filled with priming fluid by means of a pre-charge or a flush;

[0066] - requesting and / or determining a connection of the venous shunt section to the extracorporeal blood circuit with a venous section filled with priming fluid by means of a pre-charge or a flush;

[0067] - detecting a blood property in the extracorporeal blood circuit, preferably at the arterial section of the extracorporeal blood circuit, by means of a (first) blood property detection unit of the blood treatment machine and / or detecting a dialysate property at the dialysate outlet of the dialyzer by means of a (third) dialysate property detection unit of the blood treatment machine; and

[0068] - detecting and / or quantifying and / or checking a possible recirculation at the shunt at least on the basis of the blood property and / or the dialysate property detected after the connection of the venous shunt section, preferably by means of a control unit of the blood treatment machine which is in signal connection with the (first) blood property detection unit and / or the (third) dialysate property detection unit.

[0069] According to the present disclosure, it is thus achieved that the priming fluid, which would otherwise be used before the blood treatment or the treatment for flushing, is used as a bolus for detecting recirculation. That is to say, no additional or external bolus administration is necessary. According to the present disclosure, therefore, an evaluation of the recirculation at the shunt, i.e. an evaluation of the cannula fit and / or the shunt status, is achieved before or at the start of the blood treatment / treatment. This has the advantage that the subsequent blood treatment / treatment does not have to be interrupted for the detection of the recirculation. Since the recirculation can already be detected and remedial measures can be taken in the preparation phase of the blood treatment / treatment or in the preparation phase at the start of the blood treatment / treatment according to the present disclosure, a more efficient and safe extracorporeal blood treatment or treatment is possible.

[0070] Since the (first) blood property detection unit is usually arranged at the arterial section of the extracorporeal blood circuit in an integrated machine anyway, the device technology for carrying out the method according to the present disclosure is little technically demanding or no retrofitting or supplementing of the extracorporeal blood treatment machine is necessary in addition in some method variants.

[0071] The detected blood property can be a chemical property, such as a concentration, or a physical property, such as an absorption. A prerequisite for the successful detection of the recirculation is that the blood property which is set up for detection changes when the blood is diluted with the priming fluid and that the change can be detected, so that the blood property can be used as a measure of the dilution of the blood or as a measure of the recirculation.

[0072] The detected blood property is in particular a concentration of a substance in the blood. For example, the hemoglobin concentration or any other concentration that can be sensed and that changes upon dilution with the priming fluid belongs to such concentrations. A further possible blood property is the relative blood volume or hematocrit value. Alternatively or additionally, the speed of sound can be detected as blood property, since blood and priming fluid differ in the speed of sound.

[0073] The first blood property detection unit is adapted in particular to the blood property to be detected.

[0074] The priming fluid is preferably isotonic, in particular a NaCI solution with 0.9% or 9 g NaCI per 1000 ml or fresh dialysis fluid.

[0075] The respective signal connection can be configured to be wired or wireless, for example by means of Bluetooth.

[0076] According to the improvement, the recirculation at the shunt is detected at least from a deviation of the blood property detected after the connection of the venous shunt section from a reference blood property without recirculation, and / or from a value ratio of the blood property detected after the connection of the venous shunt section from a reference blood property without recirculation, and / or from an extremum or a saddle point of the blood property detected after the connection of the venous shunt section, and / or from a gradient of the blood property detected after the connection of the venous shunt section.

[0077] According to the improvement, a step is provided for quantifying the recirculation rate at the shunt by means of the control unit from the deviation and / or the value ratio and / or the gradient.

[0078] According to the improvement, the deviation is determined as a difference or a ratio of the blood property detected at different points in time or as a differential area between the blood property detected after the connection of the venous shunt section and the reference blood property without recirculation.

[0079] According to the improvement, the step of detecting the blood property at the arterial section is carried out at the latest when the venous shunt section is connected to the venous section.

[0080] According to the improvement, the step of detecting the blood property on the arterial section is carried out at least at a first point in time and at a later second point in time. Preferably, the first point in time is the point in time at which undiluted blood flows through the blood property detection unit, and the second point in time is the point in time at which blood diluted with the priming fluid will flow through the blood property detection unit in the case of recirculation.

[0081] According to the refinement, the step of joining the arterial shunt section is carried out after the step of detecting or inputting a positive interruption criterion for the rinsing, in particular bubble- free, by a (second) detection unit or an input unit of the blood treatment machine. Preferably, the (second) detection unit is configured to detect air or bubbles in the venous section.

[0082] According to a variant, the steps of joining the venous shunt section and joining the arterial shunt section are carried out during the same interruption of the rinsing, in particular during the same stop of the blood pump.

[0083] According to another variant, the step of joining the arterial shunt section and the step of joining the venous shunt section are carried out between the step of transporting the priming fluid through the venous section to the waste container, in particular by means of the blood pump. In this way, the steps of joining the arterial shunt section and joining the venous shunt section are carried out at different interruptions of the rinsing or at different stops of the blood pump, and the amount of priming fluid infused into the patient is minimized.

[0084] According to the refinement, the step of joining the venous shunt section is carried out after the step of detecting blood at the venous section by means of a second detection unit of the blood treatment machine and after the step of stopping the blood pump if blood is detected.

[0085] According to the disclosure, alternatively or in addition, a step of detecting a dialysate property at the dialysate outlet of the dialyzer by means of a (third) dialysate property detection unit of the blood treatment machine is provided. In the case of a combination, the detected blood property and the detected dialysate property can be used to check the cannula fit and / or the status of the shunt by means of the detection of recirculation.

[0086] From these two properties, an average of the recirculation rates can be determined in order to increase the accuracy of quantifying the recirculation rate.

[0087] In determining the average, or when averaging, the value of the recirculation rate determined on the blood side and the value of the recirculation rate determined on the dialysate side can be considered weighted. Alternative ways of averaging are possible.

[0088] Furthermore, the detected dialysate property can be used to check the recirculation rate quantified by means of the detected blood property in terms of plausibility. If the recirculation rates quantified by means of the detected blood property and the detected dialysate property are approximately the same, the determined recirculation rate can be trusted.

[0089] If these recirculation rates differ, one of the quantified recirculation rates behaves incorrectly, so that a step is provided in the method to output an indication that the recirculation rates do not agree and / or the shunt should be checked.

[0090] According to the refinement, the step of detecting recirculation at the shunt and / or quantifying the recirculation rate at the shunt is thus additionally performed by means of the control unit in dependence on the dialysate property detected after the joining of the venous shunt section.

[0091] According to the refinement, a step of checking the detected recirculation and / or the quantified recirculation rate is provided in dependence on the dialysate property detected after the joining of the venous shunt section.

[0092] According to the refinement, a step of detecting recirculation at the shunt and / or quantifying the recirculation rate at the shunt is performed in dependence on a deviation of the dialysate property detected after the joining of the venous shunt section from a reference dialysate property without recirculation and / or a step of checking and / or a step of checking in dependence on a gradient of the dialysate property detected after the joining of the venous shunt section.

[0093] A computer program according to the present disclosure comprises instructions which, when implemented by a computer, cause the computer to implement the method steps of the detection method according to at least one aspect of the foregoing description. BRIEF DESCRIPTION OF DRAWINGS

[0094] The present disclosure will be explained in more detail hereinafter by means of preferred embodiments with reference to the drawings in which:

[0095] Figure 1 A fluid circuit diagram of an extracorporeal blood treatment machine according to a preferred embodiment is shown;

[0096] Figure 2 Time profiles of blood properties at the shunt are shown when implementing the detection method according to a preferred embodiment, one with recirculation and one without recirculation;

[0097] Figure 3 Time profiles of blood properties at the shunt are shown when implementing the detection method according to a further embodiment, both with recirculation and one without recirculation;

[0098] Figure 4 Time profiles of dialysate properties are shown when implementing the detection method according to a further embodiment, both with recirculation and one without recirculation; and

[0099] Figure 5 A flow chart of a computer-implemented control method according to a preferred embodiment is shown.

[0100] wherein: 1 - extracorporeal blood treatment machine; 2 - dialyzer; 2.1 - dialysate input; 2.2 - dialysate output; 2.3 - blood input; 2.4 - blood output; 2.5 - semipermeable membrane; 3 - dialysate circuit; 4 - dialysate inlet; 5 - extracorporeal blood circuit; 6 - arterial cannula; 8 - first detection unit; 10 - second detection unit; 12 - venous cannula; 20 - dialysate supply; 24 - balancing device; 26 - first valve; 28 - dialysate outlet; 30 - disposal outlet; 32 - third detection unit; 34 - second valve; 38 - bypass flow path; 40 - third valve; 42 - arterial (hose) section; 44 - arterial pressure sensor; 46 - blood pump; 48 - blood input pressure sensor; 50 - venous (hose) section; 52 - blood flow output pressure sensor; 54 - control unit; 56 - storage unit; S0 - step of starting the detection method; S1 - step of flushing the extracorporeal blood circuit; S2 - step of detecting an interruption criterion of the flushing; S3 - step of coupling the arterial shunt section; S4 - step of delivering a priming fluid; S5 - step of detecting blood at the venous section; S6 - step of stopping the blood pump; S7 - step of coupling the venous shunt section; S8 - step of detecting a blood property; S9 - step of detecting recirculation; S10 - step of quantifying a recirculation rate; S11 - step of detecting a dialysate property; S12 - step of checking the recirculation or circulation rate; SE - step of ending the detection method; P - patient; S - shunt; Sa - arterial shunt section; Sv - venous shunt section; B - blood property; Bref - reference blood property; Br, Br', Br" - blood property after venous coupling; dBr, dBr', dBr" - blood property difference; ABr - blood property difference area; D - dialysate property; Dref - reference dialysate property; Dr, Dr' - dialysate property after venous coupling; dDr, dDr' - dialysate property difference; GDref - reference gradient dialysate property; GDr, GDr' - gradient dialysate property.

[0101] The drawings are essentially schematic and are merely intended for the understanding of the present disclosure. Identical elements are provided with identical reference signs. Features of the various embodiments can be replaced with each other. DETAILED DESCRIPTION

[0102] Figure 1 The fluid circuit diagram of the extracorporeal blood treatment machine 1 in the design scheme of a hemodialysis machine for extracorporeal blood treatment of blood of a patient P according to a preferred embodiment of the present disclosure is shown in a schematic view.

[0103] The extracorporeal blood treatment machine 1 has a dialyzer 2 with a dialysate circuit 3 and an extracorporeal blood circuit 5 as central components. The dialyzer 2 has a dialysate-side dialysate input 2.1 and a dialysate output 2.2 on the one hand and a blood-side blood input 2.3 and a blood output 2.4 on the other hand. Internally, the dialyzer 2 is separated into a dialysate side and a blood side by means of hollow fibers of a semipermeable membrane 2.5.

[0104] The dialysate input 2.1 is fluidically connectable, in particular connected, via a dialysate inlet 4 and a balancing device 24 to a dialysate supply 20. Fresh dialysate mixed from a permeate, a basic concentrate and an acidic concentrate is provided at the dialysate supply 20. In the dialysate inlet 4 a valve 26 for shutting off the dialysate input 2.1 is arranged.

[0105] The dialysate output 2.2 is fluidically connectable, in particular connected, via a dialysate outlet 28 and the balancing device 24 to a disposal output 30 for used dialysate / dialysate. The balancing device 24 is responsible for the fact that a desired volume of excess water can be withdrawn from the patient's blood in the context of an ultrafiltration.

[0106] In the dialysate outlet 28, between the dialysate output 2.2 and the disposal output 30, a third detection unit 32 for detecting a dialysate property D at the dialysate output, in particular for detecting a component part in the used dialysate, and an operable valve 34, preferably of the same construction type as the valve 26, for shutting off the dialysate outlet 2.2 are fluidically arranged in series.

[0107] The third detection unit 32 can be implemented in the form of an optical measuring device with a radiation emitter in the form of an LED and a photodetector, or the third detection unit is for example implemented as an electric conductivity measuring device, in particular temperature-compensated.

[0108] Alternatively or additionally, a further detection unit can be provided on the dialysate output 2.2 in order to detect a further component part in the used dialysate via this detection unit. For example, one of the detection units can detect the electric conductivity with regard to a component part A in the dialysate and another one of the detection units can detect the extinction with regard to a component part B in the dialysate.

[0109] The dialysate inlet 4 can be fluidically connected with the dialysate outlet 28 via a bypass flow path 38. In the bypass flow path 38 an operable valve 40, preferably of the same construction type as the valves 26, 34, is arranged.

[0110] By means of the valves 26, 34 and 40, the dialysis fluid circuit 3 can be switched by the control unit 54 of the blood treatment machine 1 according to the present disclosure into a main connection line in which fresh dialysis fluid is provided at the dialysis fluid input 2.1 by means of the dialysis fluid inlet 4 and is transported to the dialysate output 2.2 by means of the dialyzer 2.

[0111] In the main connection line, the valves 26 and 34 of the dialysis fluid inlet 4 and the dialysis fluid outlet 28 are manipulated by the control unit 54 into their open position, while the valve 40 in the bypass flow path 38 is manipulated into its closed position, so that the bypass flow path 38 is shut off.

[0112] Furthermore, the dialysis fluid circuit 3 can be switched by means of the fluid switching means / valves 26, 34 and 40 into a bypass line in which the dialysis fluid inlet 4 is fluidically separated from the dialysis fluid input 2.1 and the dialysate outlet 28 is fluidically separated from the dialysate output 2.2, while the dialysis fluid inlet 4 is fluidically connected to the dialysate outlet 28 via the bypass flow path 38. Fresh dialysis fluid thus does not flow through the dialyzer 2, but flows from the dialysis fluid inlet 4 (by-passing the dialyzer 2) directly to the dialysate outlet 28 via the open bypass flow path 38. In the bypass line, the lines of the valves 26, 34, 40 are reversed compared to the main connection line, that is to say, the valves 26 and 34 of the dialysis fluid inlet 4 and the dialysis fluid outlet 28 are manipulated by the control unit 54 into their lock position, while the valve 40 in the bypass flow path 38 is manipulated into its open position.

[0113] The extracorporeal blood circuit 5 has an arterial (hose) section 42 which is provided for being coupled with the arterial shunt section Sa of the shunt S. This coupling is preferably achieved by means of the arterial cannula 6 which punctures the arterial shunt section Sa. Furthermore, the extracorporeal blood circuit 5 has a venous (hose) section 50 which is provided for being coupled with the venous shunt section Sv of the shunt S. The last-mentioned coupling is preferably achieved by means of the venous cannula 12 which punctures the venous shunt section Sv.

[0114] In the extracorporeal blood circuit 5, between the arterial section 42 and the blood input 2.3 of the dialyzer 2, a first detection unit 8 for detecting a blood property B, an arterial pressure sensor 44, a blood pump 46 and a blood input pressure sensor 48 are arranged. Between the blood output 2.4 of the dialyzer 2 and the venous section 50, a blood output pressure sensor 52, a second detection unit 10 for detecting blood and air or air bubbles and a shut-off valve are arranged.

[0115] During the prescribed extracorporeal blood processing, blood is drawn from patient P via arterial cannula 6 and supplied to dialyzer 2 via blood inlet 2.3. In dialyzer 2, the blood is de-urinated and excess water is removed in countercurrent flow with the dialysate in dialysate circuit 3, and then cleanly returned / guided back to patient P. For this purpose, patient P's blood is drawn at blood outlet 2.4 and supplied to venous segment Sv of shunt S via venous segment 50 and venous cannula 12.

[0116] Control unit 54 is signal-connected to valves 26, 34, and 40, enabling it to control / manipulate these valves to the aforementioned main connection lines and bypass lines. Furthermore, control unit 54 is signal-connected to pressure detection units 44, 48, and 52, to the first, second, and third detection units 8, 10, and 32, to the balancing device 24, and to the blood pump 46.

[0117] Next, we will use Figure 2 , 3 Pairs 4 and 5 are based on the appendix Figure 1 The blood processing machine 1 is described in accordance with the computer-implemented detection method of this disclosure.

[0118] In summary, according to the detection method specified in this disclosure, the coordination of cannulas 6 and 12 at the shunt S and the state of the shunt S are evaluated by quantitatively detecting recirculation before dialysis and / or quantitatively determining the recirculation rate R.

[0119] Figure 5 A flowchart is shown of a computer-implemented detection method according to a preferred embodiment for detecting and quantifying recirculation and recirculation rate R present at the shunt S, wherein as little drainage fluid as possible is infused into the patient. The detection method according to this disclosure includes the following steps:

[0120] Especially through user input on the operating interface of the blood processing machine 1 or by following the instructions. Figure 1 The control unit 54 starts the S0 detection method.

[0121] according to Figure 1 Using a priming fluid, the extracorporeal blood circuit 5 is pre-filled / flushed S1 from the arterial segment 42, which is configured to connect with the arterial shunt segment Sa, to the venous segment 50, which is configured to connect with the venous shunt segment Sv. Preferably, this is done according to... Figure 1 The blood pump 46 is operated to perform the pre-filling / flushing S1.

[0122] The next step is to detect the positive interruption criteria of S2 for pre-filling / rinsing, preferably at least the bubble-free nature of the extracorporeal blood circuit 5 detected by the second detection unit 10.

[0123] Based on the detected interruption criteria, the blood pump is stopped and step S3 is performed to connect the arterial shunt segment Sa to the arterial segment 42, which has been pre-filled / flushed with drainage fluid. The venous shunt segment Sv is preferably left disconnected.

[0124] With the aid of blood pump 46, the drainage fluid is delivered via venous segment 50 to ( Figure 1 In step S4 (not shown), the patency fluid is placed in the waste container or delivered to the dialysate outlet 28, allowing it to be discarded through the disposal output 30. Due to the arterial connection, blood is simultaneously extracted at the arterial shunt segment Sa and delivered through the first detection unit 8. In this way, the amount of patency fluid first expelled from the extracorporeal blood circuit 5 into the waste container and then infused into the patient to detect this recirculation is minimized. On the other hand, the extracorporeal blood circuit 5 is continuously filled with blood.

[0125] If blood reaches according to Figure 1 If the vein segment 50 is detected, then the second detection unit 10 performs the step S5 of detecting blood on the vein segment 50, and if or once blood is detected, then the step S6 of stopping the blood pump 46 is performed.

[0126] With the blood pump 46 stopped, it is now possible to perform step S7 of connecting the venous shunt segment Sv to the venous segment 50 which has been pre-filled / flushed with drainage fluid, and the blood pump 46 can be restarted.

[0127] In an alternative design of the method, at the same stop of the blood pump 46 (after step S2, which detects a definite interruption criterion for pre-filling / flushing), steps S3 are performed to connect the arterial shunt segment Sa to the arterial segment 42, which has been pre-filled / flushed with drainage fluid, and step S7 to connect the venous shunt segment Sv to the venous segment 50, which has been pre-filled. Therefore, the drainage fluid clump infused to patient P is less than that in accordance with... Figure 5 The design scheme of the method is larger.

[0128] At the latest at that point in time, that is, when the two shunt segments Sa and Sv are connected and the blood pump 46 is running again, the step of detecting the blood characteristic B on the arterial segment 42 of S8 is performed by means of the first detection unit 8.

[0129] The step of detecting S8 the blood property B is performed at least at two time points: a first time point tl at which the priming fluid is displaced by blood from the arterial section 42 and at which the first detection unit 8 detects the blood property B in a state which has not yet been diluted, i.e. at which undiluted blood flows through the first detection unit 8, and a second time point t2 after which, in case of recirculation, especially when priming fluid which is transported / displaced into the venous shunt section Sv recirculates and mixes with blood in the arterial section 42, blood diluted with priming fluid flows through or will flow through the first detection unit 8. Such diluted blood is transported by the blood pump 46 from the arterial shunt section Sa into the arterial section 42 and past the first detection unit 8, where the respective time varying curve Br, Br', Br" of the blood property B corresponding to the dilution is detected and reported to the control unit 54. The detected varying curve Br, Br', Br" of the blood property B is stored in the storage unit 56 of the control unit 54 for evaluation, especially for detecting recirculation.

[0130] By means of the control unit 54, from the detected blood property Br, Br', Br" after the junction S7 of the venous shunt section Sv, the step of detecting S9 recirculation at the shunt S is performed. After the junction S7 of the venous shunt section Sv, recirculation at the shunt S is detected by means of the control unit 54 by analyzing the time varying curve Br, Br', Br" of the blood property B. As a measure for recirculation, a deviation from a reference blood property Bref without recirculation can be considered. This deviation can be taken, for example, as a differential area AB r (see Figure 2 ) of the detected blood property Br, Br', Br" at different time points tl, t2 or as a value difference dBr, dBr', dBr" (see Figure 2 and 3 ) or as a value proportion of Br, Br', Br' to Bref. An alternative or complementary possibility is to take extrema (see Figure 2 ) or saddle points with the immediate gradient Gr', Gr" (see Figure 3 ) of the detected blood property Br, Br', Br" and to use the extrema or saddle points as a measure.

[0131] Next is the step of quantifying S10 the recirculation rate R at the shunt S by means of the control unit 54 at least according to the deviation AB r, dBr, dBr', dBr" and / or the gradient Gr', Gr" and / or the value proportion of Br, Br', Br" to Bref. Additionally, the step of quantifying S10 the recirculation rate R can be realized according to further parameters, especially according to the blood transport rate or blood flow, dialysate flow, etc. at the shunt S.

[0132] As an alternative or in addition to steps S8, S9 and S10, a step S11 of detecting the dialysate property D at the dialysate outlet 2.2 of the dialyzer 2 by means of the third detection unit 32 of the blood treatment machine 1 is performed (see Figure 1 ).

[0133] Depending on the dialysate property Dr, Dr' detected after the junction S7 of the venous shunt section Sv, a step of checking S12 the detected recirculation R and / or the quantified recirculation rate R is preferably performed.

[0134] Preferably, the detection S9 of the recirculation r and / or the quantification S10 of the recirculation rate R and / or the step of checking S11 thereof is performed depending on the deviation dDr, dDr' of the dialysate property Br, Br' detected after the junction S7 of the venous shunt section Sv from the reference dialysate property of the recirculation-free Bref and / or the value ratio of Dr, Dr' and Dref and / or the gradient GDr, GDr' of the dialysate property Dr, Dr' detected after the junction S7 of the venous shunt section Sv (see Figure 4 ) and, if necessary, depending on further parameters, such as, in particular, depending on the blood delivery rate, e.g. the blood flow, the dialysate flow, etc.

[0135] Depending on the detected recirculation r or the quantified recirculation rate R, measures for eliminating the recirculation at the shunt S are taken before starting the blood treatment or therapy.

[0136] This is followed by a step SE of ending the detection method.

[0137] The computer-implemented detection method according to the present disclosure essentially completes with the ending SE step before the extracorporeal blood treatment or therapy by means of the extracorporeal blood treatment machine 1 is started at the patient P.

[0138] The starting of the extracorporeal blood treatment or therapy at the patient P is preferably characterized by the commissioning of the ultrafiltration. Then, in addition to the removal of the urinary substances from the blood, also excess water is removed from the blood.

[0139] Figure 2 A change curve of the blood property Br in the presence of recirculation in response to the above-mentioned bolus dosing is shown after the step of the junction S7 of the venous shunt section Sv. Furthermore, a reference change curve of the blood property or a reference blood property Bref is shown, which is obtained if no recirculation is present at the shunt S.

[0140] In phase I according to Figure 2 , the arterial shunt section Sv is joined (see step S3) and the blood pump 46 is delivered (see step S4). Accordingly, the blood of the patient P displaces the priming fluid located in the arterial section 42 and passes through the arterial section 42 according to Figure 1the first detection unit 8. Thus, in phase II according to Figure 2 In phase II according to the application, the signal of the blood property B of the first detection unit 8 increases sharply until it reaches its maximum B1 at the approximate time point tl.

[0141] Since the venous shunt section Sv has not yet been coupled at this time point tl (see step S7 not yet implemented) and the priming fluid is transported from the venous section 50 into the above-mentioned waste container as described before, no recirculation is sought / detected here.

[0142] As soon as blood is detected at the second detection unit 10 (see step S5), the blood pump 46 is stopped by the control unit 54 and the coupling of the venous shunt section Sv is implemented (see step S7). Subsequently, the blood pump 46 is started again.

[0143] If recirculation is now present, the arterial blood is diluted on the arterial shunt section Sa by the priming fluid flowing in from the venous section 50 and recirculating. The blood diluted in this way passes through the first detection unit 8, which detects a corresponding decrease of the detected blood property Br corresponding to the dilution / recirculation and reports to the control unit 54.

[0144] If the bolus in the venous section 50 displaces the priming fluid, the dilution decreases again and the detected blood property Br increases again in phase III. Here, for example, a minimum value B2 of the blood property B is reached at the time point t2.

[0145] The detection and / or quantification of the recirculation r / recirculation rate R can take place, for example, from the differential area ABrand / or the two values B1, B2 (see steps S9, S10).

[0146] For example, the differential area ABr limited by the time points tl, t2, the reference blood property Bref and the detected blood property Br after the coupling of the venous shunt section Sv is proportional to the recirculation rate R.

[0147] On the other hand, the recirculation rate can be calculated by means of the two values B1, B2 by the following equation:

[0148] R (%) = (1 - B2 / B1)*100%

[0149] If the quantified recirculation rate R exceeds a predetermined limit stored in the control unit 54, an acoustic and / or visual and / or haptic indication can be triggered by the control unit 54 for output by means of a display unit of the blood treatment machine 1. Here, for example, the operating personnel can be asked to check the correct fitting of the shunt S and / or the cannulae 6, 12.

[0150] If no recirculation is present, the first detection unit 8 detects a change curve of the blood property B corresponding to the blood property Bref according to Figure 2 After the connection of the venous shunt section Sv (see step S7), the detected blood property Br thus first of all remains constant, as does Bref.

[0151] Figure 3 An embodiment is shown which differs from the above-described embodiments of the detection method. Basically, the difference is that the connection of the arterial shunt section Sa (see step S3) and the venous shunt section Sv (see step S7) takes place simultaneously, that is to say, during the same stop of the blood pump 46.

[0152] The transport of the priming fluid into the above-described waste container is thus cancelled, which leads to the fact that the entire priming fluid located in the extracorporeal blood circuit 5 is transfused.

[0153] Figure 3 The time change curves of the reference blood property Bref (0%), the blood property Br' (15%) and the blood property Br" (30%) are shown for three different recirculation rates R of 0%, 15% and 30%.

[0154] In phase I according to Figure 3 The patient P is not punctured venously in phase I according to the application. That is to say, the shunt S of the patient P is perforated not only with the arterial cannula 6 but also with the venous cannula 12, or the arterial cannula 6 is connected with the arterial section 42 and the venous cannula 12 is connected with the venous section 50 (see steps S3 and S7). The extracorporeal blood circuit 5 is completely filled with priming liquid and bubble-free at this point in time as described above. In phase II, the blood pump 46 is started (point in time Bp). Arterial blood is thus simultaneously drawn from the patient and venous priming liquid is transfused. The signal at the first detection unit 8 thus rises and reaches a saddle point in phase II from which the signal runs constantly according to the blood flow rate for approximately 1 minute. The solid line shows the change curve of the reference blood property Bref, that is to say the case when there is no recirculation or the recirculation rate is 0%. The dashed line shows the change curve of the blood property Br' in the case of an average recirculation rate R of approximately 15% and the dash-dotted line shows a higher recirculation rate of approximately 30%.

[0155] According to the recirculation rate R, the level of the saddle point in phase II thus appears at different heights, since the venously transfused priming fluid mixes with the arterially drawn blood. It can be seen in phase III how the priming fluid is constantly pushed out of the extracorporeal blood circuit 5 and replaced by blood from the patient P. The signal at the first detection unit 8 thus rises and reaches a maximum value Bref in the case of no recirculation.

[0156] In phase III, the individual gradients Gr', Gr", in particular the average gradient, can be used as a measure of the recirculation rate R.

[0157] In addition to the change profile of the blood property Br, Br', Br" in phase III and / or the gradient Gr', Gr" in phase III and / or the differential area ABr and / or the difference dBr, dBr', dBr" in phase III, in order to quantify the recirculation rate, the blood flow and / or the dialysate flow and / or the ultrafiltration rate and / or the measured values and / or the dialyzer 2 used on the transition from phase II to phase III can be used independently of the embodiments.

[0158] Substances of the blood can pass from the blood into the dialysate through diffusion over the semipermeable membrane 2.5. Thus, in addition or alternatively, and analogously to the detection / quantification based on the detected blood property B, the signal response to the aforementioned bolus administration can be detected and evaluated on the dialysate side by means of a lead liquid. Here, the detection takes place by means of a third detection unit 32, and the evaluation takes place by means of the control unit 54. The third detection unit 32 can be, for example, an optical sensor which detects the absorption properties of the dialysate at at least one wavelength. In this case, all substances will contribute to the absorption of light at at least one wavelength.

[0159] Figure 4Now exemplary and schematically shown is a signal curve Dr, Dr' of the dialysate property D detected at the third detection unit 32, as derived for different recirculation rates R. In phase I the patient P is installed. That is, the patient P is punctured with the arterial cannula 6 or the arterial cannula 6 is connected with the arterial section 42 (see step S3). The blood pump 46 is started and blood is conveyed until blood on the venous section 50 is recognized by the second detection unit 10, which is configured as a blood and air detector. If the blood treatment machine 1 is in the above-mentioned main connection, that is, dialysate flows through the dialyzer 2, substances from the blood reach the dialysate side. This leads to a signal rise at the third detection unit 32, which can be observed near the end of phase I. If the blood treatment machine 1 is instead in the bypass, no signal change can be measured in this phase. The duration of phase I depends on the set blood flow rate as well as the filling volume of the extracorporeal blood circuit 5 together with the dialyzer 2 and can have a value of a few seconds up to approximately 2.5 minutes. In phase II the blood pump 46 is stopped. Now the patient P is also connected venously (see step S7). However, even in the case of a stopped blood pump 46, a substance exchange takes place at the semipermeable membrane 2.5, wherein the urinary substances and their included light-absorbing substances also pass through the membrane 2.5 and reach the dialysate side. Typically, the blood treatment machine 1 is in the above-mentioned bypass line at the time the blood pump 46 is stopped. Thereby, no dialysate or dialysate property flows along the third detection unit 32, so that the signal there remains constant. The bypass line in phase II is not necessary, so that the signal in phase II can also drop again. In the fastest case, the duration of phase II is a few seconds. In phase III the blood pump 46 is started again. At the latest in phase III, the blood treatment machine 1 is in the above-mentioned main connection in order to be able to record the associated signal change curve at the third detection unit 32. If the blood treatment machine 1 was previously in the bypass line in phase II, a saturation process takes place in the dialyzer 2 on the dialysate side. Here, the diffusing substances, which are small enough to pass through the membrane 2.5, diffuse to the dialysate side of the dialyzer 2. This "saturation mass" itself can be perceived as a short-term signal rise in phase III. Figure 4 The blood flow rate can be a preset flow rate or can be changed (increased). Phase III ends after approximately one minute.

[0160] The blood flow rate can be a preset flow rate or can be changed (increased). Phase III ends after approximately one minute.

[0161] The investigations show that the signal of the detected dialysate property Dr, Dr' varies differently depending on the recirculation rate R from phase IV onwards. The solid line shows the course of the detected dialysate property D without recirculation, i.e. the reference dialysate property Dref at R = 0%. The dashed line shows the course of the detected dialysate property Dr at moderate recirculation, for example R = 15%, and the dash-dotted line shows the course of the detected dialysate property Dr' at increased recirculation, for example R = 30%. It is apparent that the gradient GD of the detected dialysate property D decreases with increasing recirculation rate R. Phase IV usually ends after about 30 seconds. The signal reaches a constant in phase V and can decrease further in the course of the blood treatment or dialysis treatment, since more urinary substances are extracted.

[0162] For determining the recirculation rate R, in addition to the signal behavior in phase IV, the blood flow, the dialysate flow, the measured values and further parameters, for example the dialyzer 2 used, from the transition from phase IV to phase V can be used individually and / or in combination.

Claims

1. An extracorporeal blood treatment machine (1) for blood of a patient (P) having: - a dialyzer (2) with a semipermeable membrane (5), - an extracorporeal blood circuit (5) having a blood pump (46) adapted to convey fluid through the dialyzer (2), wherein, the extracorporeal blood circuit (5) extending from an arterial section (42), through a blood inlet (2.3) of the dialyzer, through the dialyzer (2) on the blood side of the semipermeable membrane (2.5), through a blood outlet (2.4) of the dialyzer (2) and to a venous section (50), wherein the arterial section is arranged for coupling an arterial shunt section (Sa) and the venous section is arranged for coupling a venous shunt section (Sv), - a dialysate circuit (3) adapted to provide and to transport fresh dialysate through the dialyzer (2) and to drain used dialysate or dialysate material, and extending from a dialysate supply (20) of the blood treatment machine (1) to a dialysate inlet (2.1) of the dialyzer (2), through the dialyzer (2) on the dialysate side of the semipermeable membrane (2.5) to a dialysate outlet (2.2) of the dialyzer (2) and to a dialysate tank (30) of the blood treatment machine (1), - a blood property detection unit (8) adapted to detect a blood property (B) in the extracorporeal blood circuit (5) and / or a dialysate property detection unit (32) adapted to detect a dialysate property (D) at the dialysate outlet (2.2), and - a control unit (54) in signal connection with the blood property detection unit (8) and / or the dialysate property detection unit (32), characterized in that the blood treatment machine (1) is arranged to, when preparing the extracorporeal blood treatment: - perform a priming or rinsing (SI) of the extracorporeal blood circuit (5) with a priming fluid from the arterial section (42) to the venous section (50), - request (S3) and / or determine a coupling of the arterial shunt section (Sa) with the arterial section (42) filled by the priming or rinsing with the priming fluid by an operator, - request (S7) and / or determine a coupling of the venous shunt section (Sv) with the venous section (50) filled by the priming or rinsing with the priming fluid by the operator, and - detect (S9) and / or quantify (S10) and / or check (S12) a recirculation (r) and / or a recirculation rate at the shunt (S) from the blood property (Br, Br', Br") and / or the dialysate property (Dr, Dr') detected after the coupling (S7) of the venous shunt section (Sv).

2. An extracorporeal blood treatment machine (1) according to claim 1, characterized in that The control unit (54) is set up to detect recirculation (r) at the shunt (S) at least from the deviation (ABr, dBr; dBr', dBr") of the blood property (Br, Br', Br") detected after the connection (S7) of the venous shunt section (Sv) from a reference blood property without recirculation (Bref) and / or from the value ratio of the blood property (Br, Br', Br") detected after the connection (S7) of the venous shunt section (Sv) from a reference blood property without recirculation (Bref) and / or from the gradient (Gr', Gr") of the blood property (Br, Br', Br") detected after the connection (S7) of the venous shunt section (Sv).

3. An extracorporeal blood treatment machine according to claim 2, characterized in that The control unit (54) is set up to quantify the recirculation rate (R) at the shunt (S) at least from the deviation (ABr, dBr; dBr', dBr") and / or from the value ratio and / or from the gradient (Gr, Gr') of the blood property (Br, Br', Br") detected after the connection (S7) of the venous shunt section (Sv) from a reference blood property without recirculation (Bref).

4. An extracorporeal blood treatment machine according to any of claims 1 to 3, characterized in that The control unit (54) is set up to store the blood property (B) at least at a first point in time (t1) and at a later second point in time (t2) and to detect the recirculation and / or to quantify the recirculation rate by means of the blood property.

5. The extracorporeal blood treatment machine according to any of claims 1 to 3, characterized in that The control unit (54) is set up to output a requirement for connecting the venous shunt section (50) and for connecting the arterial shunt section (42) during the same interruption of the rinsing.

6. An extracorporeal blood treatment machine according to any of claims 1 to 3, characterized in that The control unit (54) is set up to output a requirement for connecting the arterial shunt section (42) first and, upon determining the connection of the arterial shunt section (42), to control the guiding of the priming fluid via the venous shunt section (50) into a waste container by manipulating the blood pump (46) such that the connection of the venous shunt section (50) is realized later than the connection of the arterial shunt section (42) upon the interruption of the rinsing.

7. An extracorporeal blood treatment machine according to claim 6, characterized in that The control unit (54) is set up to receive a signal from a second detection unit (10) of the blood treatment machine (1) from blood detected at the venous section (50), to stop the blood pump (46) and to output a requirement for connecting the venous shunt section (50).

8. An extracorporeal blood treatment machine (1) according to any one of claims 1 to 3, characterized in that, The control unit (54) is configured to detect and / or quantify and / or check the recirculation (r) at the shunt (S) and / or the recirculation rate (R) at the shunt (S) at least in dependence on a deviation (dDr, dDr') of the dialysate property (Br, Br', Br") detected after the connection (S7) of the venous shunt section (Sv) from the reference dialysate property without recirculation (Bref) and / or a value ratio of the dialysate property (Dr, Dr') detected after the connection (S7) of the venous shunt section (Sv) from the reference dialysate property without recirculation (Bref) and / or a gradient (GDr, GDr') of the dialysate property (Dr, Dr') detected after the connection (S7) of the venous shunt section (Sv).

9. A computer-implemented detection method for detecting recirculation (r) at a shunt (S) of an extracorporeal blood circuit of a blood treatment machine (1) in preparation of an extracorporeal blood treatment, wherein, The blood treatment machine (1) has a dialyzer (2) with a semipermeable membrane (2.5) on which blood of the extracorporeal blood circuit (5) can exchange substances with dialysate of a dialysate circuit (3), the detection method has the steps of: - priming or flushing (S1) the extracorporeal blood circuit (5) from an arterial section (42) of the extracorporeal blood circuit, which is configured for connection with an arterial shunt section (Sa), to a venous section (50) of the extracorporeal blood circuit, which is configured for connection with a venous shunt section (Sv), with a priming fluid; - requesting and / or determining a connection (S3) of the arterial shunt section (Sa) with the arterial section (42) filled with the priming fluid by the priming or flushing; - requesting and / or determining a connection (S7) of the venous shunt section (Sv) with the venous section (50) filled with the priming fluid by the priming or flushing; - detecting (S8) a blood property (B) in the extracorporeal blood circuit (5) by means of a blood property detection unit (8) of the blood treatment machine (1) and / or detecting (S10) a dialysate property (D) on a dialysate outlet (2.2) of the dialyzer (2) by means of a dialysate property detection unit (32) of the blood treatment machine (1), and - detecting (S9) and / or quantifying (S10) and / or checking (S12) the recirculation (r) at the shunt (S) at least in dependence on the blood property (Br, Br', Br") and / or the dialysate property (Dr, Dr') detected after the connection (S7) of the venous shunt section (Sv).

10. The computer-implemented probing method of claim 9, wherein, The recirculation (r) at the shunt (2) is detected at least according to the deviation (dDr, dDr') of the dialysate property (Dr, Dr') detected after the connection (S7) of the venous shunt section (Sv) from a reference dialysate property without recirculation (Bref) and / or the value ratio of the dialysate property (Dr, Dr') detected after the connection (S7) of the venous shunt section (Sv) from a reference dialysate property without recirculation (Bref) and / or the gradient (GDr, GDr') of the dialysate property (Dr, Dr') detected after the connection (S7) of the venous shunt section (Sv).

11. The computer-implemented probing method of claim 10, wherein, The setting step: The recirculation rate (R) at the shunt (S) is quantified (S10) at least according to the deviation (ABr, dBr; dBr', dBr'') of the blood property (Br, Br', Br'') detected after the connection (S7) of the venous shunt section (Sv) from a reference blood property without recirculation (Bref) and / or the value ratio and / or the gradient (Gr, Gr') of the blood property (Br, Br', Br'') detected after the connection (S7) of the venous shunt section (Sv).

12. The computer-implemented probing method according to any one of claims 9 to 11, wherein, The step of detecting (S8) the blood property (B) is performed on the arterial section (42) at least at a first time point (tl) and at a later second time point (t2).

13. The computer-implemented probing method according to any one of claims 9 to 11, wherein, The step of connecting (S7) the venous shunt section (Sv) and the step of connecting (S3) the arterial shunt section (Sa) are achieved during the same interruption of the rinsing, or the step of connecting (S3) the arterial shunt section (Sa) and the step of connecting (S7) the venous shunt section (Sv) are achieved between the step of conveying (S4) the priming fluid through the venous section (50) into the waste container and the step of connecting (S7) the venous shunt section (Sv), so that the step of connecting (S7) the venous shunt section (Sv) and the step of connecting (S3) the arterial shunt section (Sa) are performed during different interruptions of the rinsing.

14. The computer-implemented probing method according to any one of claims 9 to 11, wherein, The recirculation (r) at the shunt (2) is detected at least according to the deviation (dDr, dDr') of the dialysate property (Dr, Dr') detected after the connection (S7) of the venous shunt section (Sv) from a reference dialysate property without recirculation (Bref) and / or the value ratio of the dialysate property (Dr, Dr') detected after the connection (S7) of the venous shunt section (Sv) from a reference dialysate property without recirculation (Bref) and / or the gradient (GDr, GDr') of the dialysate property (Dr, Dr') detected after the connection (S7) of the venous shunt section (Sv).

15. A computer program comprising instructions which, when implemented by a computer, cause the computer program to implement the method steps of the computer-implemented detection method according to any one of claims 9 to 14.

Images