Dialysis machine with three balance chambers

Description

[0001] The present invention relates to a dialysis machine with a dialyzer and with a first balancing chamber and with a second balancing chamber, each of which has at least two first and second balancing chamber halves separated from one another by a movable wall, wherein each first balancing chamber half is provided with a first inlet and a first outlet, wherein each second balancing chamber half is provided with a second inlet and a second outlet, wherein the inlets and outlets are each provided with valves which are designed to control the respective inlet and outlet.To close or open the drain, wherein the first inlets of the first balancing chamber halves are in fluid communication with a source of fresh dialysate and the first outlets of the first balancing chamber halves are in fluid communication with a dialyzer inlet, and wherein the second inlets of the second balancing chamber halves are in fluid communication with a dialyzer outlet and the second outlets of the second balancing chamber halves are in fluid communication with a drain.

[0002] Such a dialysis machine is known from the state of the art and in Figure 2 shown as an example.

[0003] EP 3 165 243 A1 relates to systems, methods and devices for controlling fluid flow in renal failure treatment systems having three balancing chambers.

[0004] Figure 2 shows a dialysis machine in the state of "normal" hemodialysis without substitution pumping.

[0005] How this Figure 2As can be seen, two balancing chambers A and B are provided, each of which has a first balancing chamber half 100, 102 and a second balancing chamber half 200, 202. The balancing chamber halves are each separated from each other by a movable wall W.

[0006] Out of Figure 2It further follows that each balancing chamber half 100, 200, 102, 202 each has a first inlet Z1 and Z3 for fresh dialysate, which is supplied via line 10, and a second inlet Z2 and Z4 for used dialysate, which is supplied from the dialyzer D via line 20. The inlets Z1 and Z2 of the first balancing chamber A can be closed by means of valves 1.1 and 1.3, the outlets A1 and A2 of the first balancing chamber A can be closed by means of valves 1.2 and 1.4. The inlets Z3 and Z4 of the second balancing chamber B can be closed by means of valves 1.5 and 1.7, and the outlets A3 and A4 of the second balancing chamber B can be closed by means of valves 1.6 and 1.8.

[0007] In the figures, the lines conveying used dialysate are shown in dashed lines. Lines conveying fresh dialysate are shown in solid lines.

[0008] Line 30 is in fluid communication with outlets A1 and A3 and serves to convey fresh dialysate to dialyzer D or to its inlet DZ. This is divided by membrane M into two or more chambers, one of which is flowed through by dialysate and the other by blood B. On the outlet side DA of dialyzer D, the used dialysate, including the ultrafiltrate, enters the secondary air separator S, which has a valve V for removing air.

[0009] From the secondary air separator S, a portion of the used dialysate is pumped into drain 1 by the ultrafiltration pump UF via line 60. The remaining portion of the used dialysate is fed in a timed manner via the inlets Z2 and Z4 to the two second balancing chamber halves 200, 202 of the balancing chambers A and B.

[0010] The line 40 is in fluid communication with the outlets A2 and A4 of the second balance chamber halves 200, 202 and serves to convey used dialysate to the drain 1.

[0011] The balanced delivery of the dialysate is designed according to Figure 2 as follows: First, fresh dialysate is pumped into the first balancing chamber half 100 of the first balancing chamber A via line 10. For this purpose, valve 1.1 is open and valve 1.2 is closed. At the same time, as wall W moves to the right, used dialysate is removed from the second balancing chamber half 200 of the first balancing chamber A via line 40 into drain 1. Valve 1.3 is closed and valve 1.4 is open. Thus, exactly one balancing chamber volume is pumped, for example, 30 ml.

[0012] The second balancing chamber B operates in a counter-clocked fashion, meaning valve 1.5 is closed, valve 1.6 is open, valve 1.7 is open, and valve 1.8 is closed. In total, used dialysate is pumped from the first balancing chamber A through the first balancing chamber A during this cycle, and fresh dialysate is pumped from the second balancing chamber B.

[0013] This is followed by a new cycle of the balancing chamber system, in which fresh dialysate is pumped from the first balancing chamber half 100 of the first balancing chamber A and used dialysate is pumped from the second balancing chamber half 202 of the second balancing chamber B.

[0014] The process described above repeats itself in a continuous sequence.

[0015] The same amount of fresh dialysate and used dialysate is always pumped and precisely balanced.

[0016] Due to the dehydration of the patient, additional ultrafiltrate is produced on the used dialysate side, which is pumped by the UF pump located in line 60.

[0017] During one treatment, approximately 2 liters of ultrafiltrate are produced per patient and the treatment duration is approximately 4 hours.

[0018] The amount of ultrafiltrate is controlled by the ultrafiltrate pump UF, which draws the ultrafiltrate from the patient's blood.

[0019] The arrangement known from the prior art according to Figure 2 ensures precise control of dialysate volumes (fresh and used) and ultrafiltrate volume. Controlling the ultrafiltrate volume is important because a minimum amount must be maintained to prevent overhydration of the patient, and excessively rapid dehydration can lead to circulatory collapse.

[0020] According to the state of the art, an additional amount of dialysate or fluid can be delivered to the patient via a separate pump (substitution pump) (not shown). This is necessary if a larger amount of ultrafiltrate is withdrawn from the blood than prescribed for the patient. The substitution can then (usually) be added after the dialyzer. In principle, it is also possible to add it before or before and after the dialyzer. Substitution amounts between 20 and 40 liters per treatment cycle are common.

[0021] This process is called HDF (hemodiafiltration). The HDF mode has the advantage of allowing a higher convective fraction to be transported across the dialyzer membrane, thus allowing particularly effective removal of medium-molecular urea toxins, which can only be transported across the membrane to a limited extent by diffusion.

[0022] In addition to the substituate pump, existing devices require an additional filter for the substituate to ensure sterile filtration of the substitute. This is necessary because the substituate is infused directly into the patient's blood.

[0023] Such an arrangement is therefore complicated and expensive.

[0024] The present invention is therefore based on the object of developing a dialysis machine of the type mentioned at the outset in such a way that it has the simplest possible structure.

[0025] This object is achieved by a dialysis machine having the features of claim 1. According to this, a third balancing chamber is provided which has two balancing chamber halves which are separated from one another by a movable wall, wherein each of the balancing chamber halves of the third balancing chamber has an inlet and an outlet, which are each provided with valves which are designed to close or open the respective inlet or outlet, wherein the two inlets are in fluid communication with a source of fresh dialysate / substituteate and wherein the two outlets are in fluid communication with the dialyzer inlet.

[0026] The third balancing chamber is therefore not filled with used dialysate. Instead, it serves exclusively to pump fresh dialysate or substitute dialysate.

[0027] The third balancing chamber can be controlled in such a way that it operates either staggered in time or simultaneously with the first and second balancing chambers. Simultaneous operation offers the advantage that balancing, and thus the operation of the dialysis machine, can be continued and does not need to be interrupted when substituate, i.e., preferably fresh dialysis solution, is supplied to the dialyzer via the third balancing chamber.

[0028] The third balancing chamber thus serves to convey fresh dialysate or substituate to the dialyzer, so that in an advantageous embodiment of the invention a separate substituate pump can be dispensed with.

[0029] The fluid volume delivered continuously or discontinuously by the third balancing chamber (e.g., 1 pump, 30 ml) serves as a substitute for the patient. At the same time, the dialyzer membrane acts as a sterile filter for the substitute, so that in a preferred embodiment of the invention, neither a separate substitute pump nor a separate sterile filter is required. Furthermore, no separate tubing set is required for the substitute.

[0030] By switching the valves of the third balancing chamber back and forth, a volume of each half of the balancing chamber can now be pumped into the system circuit as a substitute.

[0031] Preferably, the two inlets of the third balancing chamber are fluidly connected to the same source of fresh dialysate as the first inlets of the first and second balancing chambers, i.e., the balancing chambers are fed with fresh dialysate from the same source. In principle, it is also conceivable for the inlets of the third balancing chamber to be fed from a different source than the first inlets of the second and third balancing chambers, so that, for example, a different solution can be used for the substitution product than for the dialysate.

[0032] In a further embodiment of the invention, the two outlets of the third balancing chamber are in direct fluid communication with the same line leading to the dialyzer inlet as the first outlets of the first and second balancing chambers. The two outlets of the third balancing chamber preferably open into the same line as the first outlets of the first and second balancing chambers.

[0033] Furthermore, the device can be configured without its own substitution pump for pumping a substitution solution into the patient's blood. This simplifies the device's design accordingly. As explained, in this case, the third balancing chamber functions as the substitution pump, and the dialyzer membrane functions as the sterile filter.

[0034] One or both balance chamber halves of the third balance chamber can have a smaller volume than the balance chamber halves of the first and second balance chamber in order to achieve particularly precise dosing by means of the third balance chamber.

[0035] To enable slow dosing from the third balancing chamber, a throttle device can be arranged upstream and / or downstream of the third balancing chamber, which is designed to throttle the inflow and / or outflow of fresh dialysate from the third balancing chamber. The throttle device can be, for example, an orifice, a constriction, a valve, etc. The throttle device can be adjustable so that the degree of throttling can be varied, or it can be non-adjustable.

[0036] The dialysis machine can be equipped with a control system configured to deliver fresh dialysate to the dialyzer from the third balancing chamber evenly or unevenly throughout the treatment. Examples include intermittent delivery, constant delivery, or variable delivery, such as profiled delivery from the third balancing chamber.

[0037] The dialyzer can be, for example, a high-flux dialyzer or a mid-cut-off dialyzer. High-flux dialyzers are filters that have an ultrafiltration rate of 20–70 mL / m2 * mmHg * h in human blood. With these dialyzers, the inventive substitution delivery is particularly easy to achieve due to the high water permeability in whole blood. Substitution amounts of 5 to 25 l per 4-hour treatment are preferably set, particularly preferably 15 to 25 l per 4-hour treatment.

[0038] The dialysis machine according to the invention is particularly efficient with mid-cut-off or "protein-leaking" dialyzers. Such dialyzers exhibit an even higher ultrafiltration rate in whole blood than high-flux dialyzers, but the increased albumin loss, which can amount to up to 8 g in a 4-hour treatment, proves to be a disadvantage. With mid-cut-off dialyzers, substitution agent delivery occurs through uncontrolled backfiltration. With a dialysis machine according to the invention, the substitution agent quantity can be precisely controlled. In particular, higher substitution agent quantities are possible than with a state-of-the-art dialysis machine operated with a mid-cut-off dialyzer. This allows the optimal substitution agent quantity to be provided, taking into account the permissible albumin loss, even with varying hematocrit values ​​of the patient's blood.According to the invention, substituate amounts of 5–20 l can be adjusted for a 4-hour HD treatment. Substituate amounts of 8 to 15 l per 4-hour treatment are preferred.

[0039] The present invention further relates to a control unit configured to carry out a method for operating a balancing chamber system of a dialysis machine with a first balancing chamber and with a second balancing chamber, each of which has at least two first and second balancing chamber halves separated from one another by a movable wall, wherein each first balancing chamber half is provided with a first inlet and a first outlet, wherein each second balancing chamber half is provided with a second inlet and a second outlet, wherein the inlets and outlets are each provided with valves which are designed to control the respective inlet and outlet.To close or open the drain, wherein the first inlets of the first balance chamber halves are in fluid communication with a source of fresh dialysate and the first outlets of the first balance chamber halves are in fluid communication with a dialyzer inlet, and wherein the second inlets of the second balance chamber halves are in fluid communication with a dialyzer outlet and the second outlets of the second balance chamber halves are in fluid communication with a drain.

[0040] According to the invention, a third balancing chamber is provided which has two balancing chamber halves which are separated from one another by a movable wall, wherein each of these balancing chamber halves has an inlet and an outlet, which are each provided with valves, wherein the two inlets are in fluid communication with a source of fresh dialysate and wherein the two outlets are in fluid communication with the dialyzer inlet, wherein the valves of the third balancing chamber are operated such that fresh dialysate is conveyed from the third balancing chamber to the dialyzer inlet.

[0041] The term "dialysate" delivered through the third balancing chamber encompasses any dialysate and substitute dialysate. This may be the same dialysate used in the first and second balancing chambers or a different solution.

[0042] Preferably, the valves of the third balancing chamber are operated in such a way that a continuous flow of fresh dialysate from the third balancing chamber to the dialyzer inlet is achieved. In this case, a continuous supply of dialysate or substituate to the dialyzer and thus also to the patient via the dialyzer membrane results.

[0043] However, the invention also covers the case where the third balancing chamber is operated discontinuously.

[0044] In order to achieve a targeted slow dosage of substituate, it can be provided that the supply of fresh dialysate to the third balancing chamber and / or the removal of fresh dialysate from the third balancing chamber to the dialyzer inlet is throttled.

[0045] An evaluation and control unit can be provided that is designed to operate the third balancing chamber in such a way that the medically prescribed substitution dose is distributed evenly over the duration of treatment. It is also conceivable that the evaluation and control unit is designed so that the medically prescribed substitution dose is distributed unevenly over the duration of treatment. For example, it is conceivable that the substitution dose is larger at the beginning of treatment than at the end, that a profiled addition of substitution dose occurs, etc.

[0046] As explained, it is advantageous if no substitution pump is used to deliver substitution fluid to the patient. This is not necessary, since the substitution fluid delivered by the third balancing chamber is at least partially delivered to the patient via the dialyzer membrane.

[0047] It should be noted here that the terms "a" and "an" do not necessarily refer to exactly one of the elements, although this is a possible interpretation, but can also refer to a plurality of the elements. Likewise, the use of the plural also includes the presence of the element in question in the singular, and conversely, the singular also encompasses several of the elements in question.

[0048] Further details and advantages of the invention are explained in more detail with reference to an embodiment shown in the drawing.

[0049] They show: Figure 1: a schematic view of the dialysate circuit of a dialysis machine according to the invention and Figure 2: a schematic view of the dialysate circuit of a dialysis machine according to the prior art.

[0050] In Figure 1 Identical or functionally equivalent elements are marked with the same reference symbols as in Figure 2, so that reference is made accordingly.

[0051] The operation of the dialysis machine according to the invention according to Figure 1 is as follows.

[0052] The clocked operation of the first and second balancing chambers A, B is as follows: Figure 2 described, so that reference is made to the explanations there.

[0053] A third balancing chamber C is connected in parallel to the first and second balancing chambers A, B.

[0054] The third balancing chamber has two inlets Z5, Z6, which are connected to the same line 10 as the inlets Z1 and Z3 of the first and second balancing chambers A, B. In contrast to the first and second balancing chambers, the third balancing chamber is supplied with fresh dialysate from line 10 at both inlets. Used dialysate is not fed from the dialyzer to the third balancing chamber. Accordingly, the third balancing chamber conveys only fresh dialysate from the outlets A5, A6 to the dialyzer, which serves as a substitute for the patient by at least partially passing through the dialyzer membrane M into the patient's blood. The removal of fresh dialysate from the third balancing chamber C occurs via the same line as the removal of fresh dialysate from the first and second balancing chambers. This line leads directly from the respective outlets of the balancing chamber halves to the dialyzer inlet.

[0055] The operation of the third balance chamber otherwise corresponds to that of the first and second balance chamber, ie while one half of the balance chamber is filled with the corresponding valve switching, the other half of the balance chamber is emptied by the resulting displacement of the wall W and vice versa.

[0056] At the same time, the dialyzer membrane acts as a sterile filter for the substitute. A sterile filter specifically designed for the sterilization of substitute is no longer necessary.

[0057] The advantage is that no separate substitution pump, separate tubing set, or separate sterile filter is required. The third balancing chamber functions as the substitution pump, and the dialyzer membrane functions as the sterile filter.

[0058] Preferably, no separate substitution line is required, since the substitution line is fed to the dialyzer through the same line as the dialysate, which is conveyed through the first and second balancing chamber.

[0059] The device may comprise an evaluation and control unit that distributes the medically prescribed amount of substitute medication evenly over the duration of treatment.

[0060] The device may include an evaluation and control unit that distributes the medically prescribed substitution dose unevenly over the course of treatment. This means, for example, that the substitution dose may be higher or lower at the beginning of treatment than at the end.

[0061] The device works particularly well when using dialyzers known as high-flux dialyzers. High-flux dialyzers are filters that have an ultrafiltration rate of 20-70 ml / m 2 < * mmHg * h in human blood.

[0062] The device according to the invention is particularly effective in conjunction with a so-called mid-cut-off dialyzer. Such a dialyzer is described, for example, in WO 2015 / 118046 A, to which reference is made here. Such dialyzers exhibit uncontrolled backflushing of dialysate into the bloodstream, which is caused by the internal pressure conditions within the dialyzer. These dialyzers must not be operated in HDF mode, as otherwise the loss of albumin would be significantly too high.

[0063] With the aid of the device according to the invention, a "normal" machine can now be operated in "controlled substituate mode." In particular, through skillful program selection, the amount of substituate can be limited to volumes between 2 and 15 l per treatment, preferably to volumes between 5 and 12 l per treatment, and more preferably to volumes between 5 and 10 l per treatment.

Claims

1. A dialysis machine having a dialyzer (D) and having a first balancing chamber (A) and having a second balancing chamber (B) of which each has at least two first (100, 102) and second balancing chamber halves (200, 202) separated from one another by a movable wall (W), wherein each first balancing chamber half (100, 102) is provided with a respective first inflow (Z1, Z3) and with a respective first outflow (A1, A3), wherein each second balancing chamber half (200, 202) is provided with a respective second inflow (Z2, Z4) and with a respective second outflow (A2, A4), wherein the inflows and outflows (A1-A4, Z1-Z4) are each provided with valves (1.1-1.4; 2.1-2.4) that are configured to close or to open the respective inflow (Z1-Z4) or outflow (A1-A4), wherein the first inflows (Z1; Z3) of the first balancing chamber halves (100; 102) are in fluid communication with a source of fresh dialyzate and the first outflows (A1; A3) of the first balancing chamber halves (100; 102) are in fluid communication with a dialyzer inflow (DZ), and wherein the second inflows (Z2; Z4) of the second balancing chamber halves (200; 202) are in fluid communication with a dialyzer outflow (DA) and the second outflows (A2; A4) of the second balancing chamber halves (200; 202) are in fluid communication with a drain (1), characterized in that the dialysis machine has a third balancing chamber (C) is provided that has two balancing chamber halves (104; 204) that are separated from one another by a movable wall (W), with each of the balancing chamber halves (104; 204) having a respective inflow (Z5; Z6) and a respective outflow (A5; A6) that are each provided with valves (V1-V4) that are configured to close or to open the respective inflow (Z5; Z6) or outflow (A5; A6), with the two inflows (Z5; Z6) being in fluid communication with a source of fresh dialyzate and with the two outflows (A5; A6) being in fluid communication with the dialyzer inflow (DZ).

2. Dialysis machine in accordance with claim 1, characterized in that the two inflows (Z5; Z6) of the third balancing chamber (C) are in fluid communication with the same source of fresh dialyzate as the first inflows (Z1; Z3) of the first and second balancing chambers (A; B).

3. Dialysis machine in accordance with claim 1 or claim 2, characterized in that the two outflows (A5; A6) of the third balancing chamber (C) are in fluid communication with the same line (30) leading to the dialyzer inflow (DZ) as the first outflows (A2; A4) of the first and second balancing chambers (A; B).

4. Dialysis machine in accordance with one of the preceding claims, characterized in that the machine does not have any substituate pump for conveying a substitution solution into the blood of the patient.

5. Dialysis machine in accordance with one of the preceding claims, characterized in that the balancing chamber halves (104; 204) of the third balancing chamber (C) have a smaller volume than the balancing chamber halves of the first and second balancing chambers (A; B).

6. Dialysis machine in accordance with one of the preceding claims, characterized in that a throttle member is arranged upstream and / or downstream of the third balancing chamber (C), said throttle member being configured to throttle the inward flow and / or the outward flow of fresh dialyzate from the third balancing chamber (C).

7. Dialysis machine in accordance with one of the preceding claims, characterized in that a control is provided that is configured to carry out the supply of fresh dialyzate to the dialyzer (D) from the third balancing chamber (C) evenly in time or unevenly in time over the treatment duration.

8. Dialysis machine in accordance with one of the preceding claims, characterized in that the dialyzer (D) is a high-flux dialyzer or a medium cut-off dialyzer.

9. Control unit, configured for performing a method of operating a balancing chamber system of a dialysis machine having a first balancing chamber (A) and having a second balancing chamber (B) of which each has at least two first (100, 102) and second balancing chamber halves (200, 202) separated from one another by a movable wall (W), wherein each first balancing chamber half (100, 102) is provided with a respective first inflow (Z1, Z3) and with a respective first outflow (A1, A3), wherein each second balancing chamber half (200, 202) is provided with a respective second inflow (Z2, Z4) and with a respective second outflow (A2, A4), wherein the inflows and outflows (A1-A4, Z1-Z4) are each provided with valves (1.1-1.4; 2.1-2.4) that are configured to close or to open the respective inflow (Z1-Z4) or outflow (A1-A4), wherein the first inflows (Z1; Z3) of the first balancing chamber halves (100; 102) are in fluid communication with a source of fresh dialyzate and the first outflows (A1; A3) of the first balancing chamber halves (100; 102) are in fluid communication with a dialyzer inflow (DZ), and wherein the second inflows (Z2; Z4) of the second balancing chamber halves (200; 202) are in fluid communication with a dialyzer outflow (DA) and the second outflows (A2; A4) of the second balancing chamber halves (200, 202) are in fluid communication with a drain (1), characterized in that the dialysis machine has a third balancing chamber (C) that has two balancing chamber halves (104; 204) that are separated from one another by a movable wall (W), with each of the balancing chamber halves (104; 204) having a respective inflow (Z5; Z6) and a respective outflow (A5; A6) that are each provided with valves (V1-V4), with the two inflows (Z5; Z6) being in fluid communication with a source of fresh dialyzate and with the two outflows (A5; A6) being in fluid communication with the dialyzer inflow (DZ), with the valves (V1-V4) being operated such that fresh dialyzate is conveyed from the third balancing chamber (C) to the dialyzer inflow (DZ).

10. Control unit in accordance with claim 9, characterized in that the valves (V1-V4) of the third balancing chamber are operated such that a continuous flow of fresh dialyzate results from the third balancing chamber (C) to the dialyzer inflow (DZ).

11. Control unit in accordance with claim 9 or claim 10, characterized in that the third balancing chamber (C) is operated continuously or discontinuously.

12. Control unit in accordance with one of the claims 9 to 11, characterized in that the supply of fresh dialyzate to the third balancing chamber (C) and / or the removal of fresh dialyzate from the third balancing chamber (C) to the dialyzer inflow is throttled.

13. Control unit in accordance with one of the claims 9 to 12, characterized in that the third balancing chamber (C) is operated such that the conveying rate of fresh dialyzate from the third balancing chamber (C) to the dialyzer inflow is constant or varied over the treatment duration.

14. Control unit in accordance with one of the claims 9 to 13, characterized in that no substituate pump is used to supply substituate to the patient.