DIALYSIS MACHINE

Description

[0001] The invention relates to a dialysis machine which is designed to be equipped with an extracorporeal blood system, with a dialysis solution system which is designed to be equipped with a dialyzer, wherein a mixing area, in particular a mixing chamber, is provided in which the fresh dialysis solution or a component thereof is located during operation of the dialysis machine, wherein a concentrate line is in fluid communication with the mixing area, through which concentrate from a concentrate container can be introduced into the mixing area.

[0002] Dialysis machines of the type mentioned above are known from the prior art. They are used during dialysis treatment to remove urea and other substances from the blood of a patient with absent or reduced kidney function. The dialyzer of a dialysis machine is a filter unit with a blood chamber and a dialysis solution chamber separated by a semipermeable membrane. The substances to be removed from the blood pass through the semipermeable membrane in the dialyzer from the blood chamber into the dialysis solution chamber.

[0003] To balance the amount of dialysis solution supplied to and removed from the dialyzer, a so-called balancing chamber is usually used. This has two balancing chamber halves separated from each other by a movable wall, each with an inlet and an outlet that can be opened and closed by a valve. While one of the balancing chamber halves is filled with fresh dialysis solution, the wall moves away from the filling balancing chamber half, thereby displacing the used dialysis solution in the other balancing chamber half. Since both balancing chamber halves are located in the same balancing chamber with solid walls, the volume of fresh dialysis solution supplied corresponds to the volume of used dialysis solution removed.

[0004] It should be noted at this point that the dialysis machine according to the present invention can, but is not necessarily required to, have such a balancing chamber system; it is thus a preferred, yet optional feature. The at least one balancing chamber is thus an optional component of the dialysis machine. As an alternative to the use of one or more balancing chambers, the use of flow sensors with pumps for balancing is possible, for example, which is also encompassed by the invention.

[0005] In principle, it is possible to supply dialysis machines with a ready-to-use dialysis solution, which is provided, for example, in a container or in a supply line.

[0006] US5318750 discloses a device for preparing a dialysis solution by dissolving several powdered substances in water. The device comprises a number of independent cartridges, each containing a salt of a substance required for the preparation of the dialysate, such as sodium chloride, potassium chloride, calcium chloride, magnesium chloride, and sodium bicarbonate. The device comprises at least one first line connected to an inlet to the cartridges for introducing water into the cartridges to generate aqueous solutions in the cartridges, at least one second line connected to an outlet from the cartridges for conveying the aqueous solutions to a mixing point located upstream of a dialysis circuit, and a first measuring device attached to the second line upstream of the mixing point.to measure the concentration of the aqueous solutions at the outlet of the cartridges, a second measuring device mounted downstream of the dialysis circuit, and at least one flow regulating device for regulating the flow rate of the water in order to vary the concentration of the aqueous solutions depending on the information provided by the first and second measuring devices.

[0007] US5295505 discloses a device for producing a medical solution, in particular a dialysis solution, from powdered concentrate and water. The device comprises a water source, from which a first line leads to a container containing the powder, and from which a second line, into which a first measuring cell and a concentrate pump are connected, leads to a mixing point. This mixing point is located in a third line leading from the water source to a consumer; downstream of the mixing point, a second measuring cell is provided for monitoring the composition of the finished dialysis solution.

[0008] It is also known from the prior art to produce the ready-to-use dialysis solution on the dialysis machine itself, typically by mixing several concentrates with RO water in a mixing area. These concentrates are pumped from concentrate containers to the mixing area, which is preferably designed as a mixing chamber. Two concentrate containers are typically used, one containing a basic concentrate and one containing an acidic concentrate. The mixture obtained in this way represents the ready-to-use dialysis solution and is then pumped to the balancing chamber and from there to the dialyzer.

[0009] A known dialysis machine with features of the preamble of claim 1 is described in Figure 1 shown schematically.

[0010] The patient P is connected via the extracorporeal blood circuit K to the dialyzer 10, which has a blood-side compartment 14 and a dialysate-side compartment 12, which are separated from each other by a semipermeable membrane M. The patient's blood is preferably passed through the dialyzer 10 in countercurrent to the dialysis solution, as indicated by arrows that represent the flow direction.

[0011] The hydraulic system of the dialysis machine, ie the dialysis solution system, is generally designated by the reference numeral 100.

[0012] The dialysis solution is prepared in the mixing chamber 20 from the liquid flowing through line 30, preferably RO water (RO = reverse osmosis), as well as from the two concentrates flowing into the mixing chamber 20 through lines 40, 50. The concentrates are conveyed by means of pumps 41, 51, which convey the concentrate from the concentrate containers 42, 52.

[0013] The line L5 arranged on the mixing chamber 20 serves to vent the dialysis solution and can be closed by the valve V.

[0014] The balancing chamber 60 has the above-mentioned balancing chamber halves 61 and 62, which are separated from each other by the movable wall W which is not permeable to dialysis solution.

[0015] To ensure a continuous flow, two parallel balancing chambers 60 are provided, as shown in Figure 1 These can be constructed identically. The balance chambers are shown in a simplified manner in that their inner walls are preferably shaped so that the wall W can fit completely against them in its extreme positions.

[0016] Each balancing chamber half 61, 62 of a balancing chamber 60 has a valve on the inlet and outlet side to control the inflow and outflow into and out of the balancing chamber halves.

[0017] The two balancing chamber halves 61 of the balancing chambers 60 shown on the left serve to receive fresh dialysis solution from line L1. From the balancing chamber halves 61, the dialysis solution flows via line L2 into the dialysate-side compartment 12 of the dialyzer 10. The two balancing chamber halves 62 of the balancing chambers 60 shown on the right serve to receive used dialysis solution, which flows via line L3 from the dialyzer 10 to the balancing chamber halves 62 and, after the balancing chamber, is led via line L4 to a drain (Drain D).

[0018] If one or both of the concentrate containers 42, 52 are empty, air may enter the balancing chamber or another balancing system, resulting in a balancing error because the affected half of the balancing chamber or a pump for balancing the solution is then not completely filled with fresh dialysis solution, but partially filled with air, and thus less fresh dialysis solution is delivered to the dialyzer than expected. In these cases, air is conveyed or entrained via the concentrate lines into the mixing chamber and from there into the balancing chamber or another balancing system.

[0019] This entrainment of air occurs, for example, by opening the vent valve V during the dead time of the balancing chamber. The dead time of the balancing chamber is the period of time during which the wall W is in an extreme position (deflection completely to the right or left) and all valves of the balancing chamber are closed. This state can last, for example, 100 ms.

[0020] Figure 2 shows the pressure curve during a balance chamber cycle, with time t1 marking the dead time. As can be seen from Figure 2 marked by an arrow V, at this time t1 the valve V is opened briefly. Then the valve V is closed and the inlet valve of the balancing chamber is opened, so that the pressure in the filling half of the balancing chamber 61 increases. This filling phase is in Figure 2marked with T2. In the subsequent state T3, the balancing chamber half is completely filled, which is also referred to as the high-pressure phase of the balancing chamber.

[0021] The reference symbol BZ denotes the entire balance chamber half cycle, which includes all these phases or points in time.

[0022] When valve V is open, the air rises in lines 40, 50 and is then entrained into the balancing chamber or balancing chamber half 61 by the filling flow, which fills the balancing chamber 61. This leads to an incorrect balance.

[0023] The present invention is therefore based on the object of developing a dialysis machine according to the preamble of claim 1 in such a way that the probability of air being introduced into the dialysis solution or into a balancing system of the dialysis machine is reduced compared to known dialysis machines.

[0024] This object is achieved by a dialysis machine having the features of claim 1.

[0025] According to this, it is provided that at least two electrically conductive elements are arranged spaced apart from one another in or on the concentrate line(s), that a measuring device is provided which is in electrical connection with the conductive elements and which is designed to measure the conductance or a variable correlated therewith between them, and that a control unit is provided which is designed to compare the measured value with a target value or with a limit value or with a target value range.

[0026] The at least two conductive elements can be arranged in or on the same concentrate line and / or in or on different concentrate lines.

[0027] It is conceivable that exactly one electrically conductive element is arranged in or on a concentrate line and / or that one or more concentrate lines are provided, in or on each of which several electrically conductive elements are arranged. An embodiment is thus conceivable in which one (or more) concentrate lines is / are each provided with at least two electrically conductive elements. Alternatively or additionally, it can be provided that two or n (n>2) concentrate lines with a total of two or n (n>2) electrically conductive elements are present, i.e., one electrically conductive element is provided for each concentrate line.

[0028] The measurement takes place between the two electrically conductive elements, regardless of whether they are located in the same or different concentrate lines.

[0029] The electrically conductive element(s) may be designed as electrodes.

[0030] A conceivable arrangement is one in which one or at least one electrically conductive element is arranged in each of two concentrate lines, and the two concentrate lines, together with the mixing chamber or another mixing area, form a conductive path over which a signal (e.g. the conductivity or a value correlated therewith) can be measured from the electrically conductive element of one concentrate line to the electrically conductive element of the other concentrate line. One concentrate line can, for example, be the line for the acidic concentrate and the other concentrate line the line for the basic concentrate. This signal is interrupted when one or both concentrate containers are empty or when air or an air / concentrate mixture is being pumped through the concentrate lines.

[0031] The concentrate lines are preferably designed as hoses.

[0032] Thus, the conductance, ie the inverse of the ohmic resistance or a value correlated with it, such as the voltage, the current, the ohmic resistance, etc., is measured, whereby the measurement takes place between the two electrically conductive elements.

[0033] If there is concentrate in the concentrate line, i.e., in the supply line, the electrical circuit is closed, resulting in a high conductivity. If air enters the concentrate line, the conductivity drops. If the conductivity falls below a limit, i.e., if it moves outside a target range, the presence of air can be detected, and an alarm can be triggered, for example.

[0034] The electrically conductive elements can be formed, for example, by hose nozzles that are arranged at a distance from one another in the longitudinal direction of the concentrate line.

[0035] The electrically conductive elements are arranged on or in the concentrate line(s) in such a way that they come into contact with the contents of the concentrate line, i.e. with the concentrate, air, etc.

[0036] The electrically conductive elements are preferably made of metal, preferably stainless steel and / or titanium.

[0037] Preferably, a concentrate pump is located in or on the concentrate line, with the conductive elements preferably located upstream of the concentrate pump in the direction of flow of the concentrate to avoid impaired detection of air, such as that present downstream of the concentrate pump. In principle, the invention also encompasses the case where the conductive elements are located downstream of the concentrate pump in the direction of flow of the concentrate.

[0038] The control unit is designed to initiate a special operating mode of the dialysis machine and, if necessary, an alarm if the measured value (conductance or a value correlated with it) does not match the target value, exceeds or falls below a limit, or is not within a target value range. As explained above, this is particularly the case if there is air or an air / concentrate mixture, rather than pure concentrate, in the area of ​​the concentrate line between the electrically conductive elements.

[0039] Preferably, the control unit or its detection logic is designed for a specific distance between the two conductive elements. If the distance between the conductive elements changes, it may be necessary to adjust the control unit's detection logic accordingly.

[0040] In a further embodiment of the invention, the control unit is designed such that the alarm and / or the special operating mode of the dialysis machine is only initiated when the measured value does not agree with the target value more often than a threshold value or exceeds or falls below a limit value or is not within a target value range.

[0041] If the dialysis machine has a balancing chamber system, it is conceivable that a counter is incremented by one if air is detected in the concentrate line during a balancing chamber cycle, and decremented by one if no air is detected in the concentrate line during a balancing chamber cycle. If, for example, the value 5 (or another value) is exceeded or reached in this way, an alarm is triggered and / or the dialysis machine's special operating mode is initiated. This procedure prevents small air bubbles or unforeseen sensor fluctuations from triggering an alarm and / or initiating the dialysis machine's special operating mode every time.

[0042] This system is not limited to the existence of a balancing chamber system, but also includes systems without a balancing chamber system.

[0043] The special operating mode may include a special air separation deviating from normal operation and / or the flushing of the dialysis solution system or part of it and / or the increase in the flow rate of the dialysis solution and / or the bypassing of the dialyzer and, if necessary, other measures.

[0044] The present invention relates to a dialysis machine that is equipped to accommodate an extracorporeal blood system, such as a blood tubing set, and a dialyzer. The extracorporeal blood system and / or the dialyzer are therefore not mandatory components of the machine. Nevertheless, the invention also encompasses a dialysis machine in which the extracorporeal blood system and / or the dialyzer are incorporated into the dialysis machine.

[0045] A bypass circuit of the dialyzer means that the dialysis solution does not flow through the dialyzer, but is bypassed in a bypass line.

[0046] Flushing of the dialysis solution system, or a portion of it, only occurs after the special air separation process. Flushing ensures that the dialysis solution circuit contains ready-to-use dialysis solution with the correct composition when the patient is reconnected and treatment is resumed.

[0047] It is preferably provided that there is no air separation means, in particular no air separation chamber, in the concentrate line and / or between the mouth of the concentrate line into the mixing area and a balancing chamber or other balancing system of the dialysis solution system.

[0048] This allows for cost reduction. Preferably, the control unit continues to operate the concentrate pump, so that (after connecting a new concentrate container) it is necessary to wait until the concentrate is drawn in by normal pumping activity. To remove the air drawn in until then and the incorrectly mixed dialysis solution from the dialysis solution system, special air separation and flushing of the dialysis solution system, i.e., the hydraulic system or a part of it, are preferably performed.

[0049] Preferably, the control unit is designed such that, in the operating state of the special air separation of the dialysis machine, it opens and closes a valve one or more times when the balancing chamber half of the balancing chamber fluidically connected to the said line is in its high-pressure phase. In this case, all valves of the balancing chamber are closed. This special air separation removes air from the mixing area, from the concentrate line(s), and from the line leading to the balancing chamber.

[0050] The mixing area, in particular the mixing chamber, can be connected to a fresh water connection, in particular to an RO water connection, or can be connected to it.

[0051] A method for operating a dialysis machine according to one of the preceding claims can be designed such that the conductivity or a value correlated therewith is measured on two electrically conductive and spaced-apart elements in or on the concentrate line(s), with the measured value being compared with a target value, limit value, or target value range. The above statements regarding the dialysis machine apply accordingly to the arrangement of the electrically conductive elements.

[0052] The control unit can be formed by a single component that performs various tasks, such as comparing the measured value with a setpoint, limit value or setpoint range, initiating the alarm and / or the special operating mode, etc. However, the control unit can also be formed by several separate components that perform various of these tasks, ie the control unit does not necessarily have to consist of a single component.

[0053] Preferably, if the measured value does not correspond to a target value or is not within a target value range or exceeds or falls below a limit value, an alarm and / or a special operating mode of the dialysis machine is initiated.

[0054] As explained above, the special mode of operation may include a special air separation deviating from normal operation and / or the flushing of the dialysis solution system or a part thereof and / or the increase of the flow rate of the dialysis solution and / or the bypassing of the dialyzer.

[0055] It is conceivable that, during the operating mode of the dialysis machine's special air separation, the valve is opened and closed one or more times when the balancing chamber half of the balancing chamber that is in fluid communication with the line is in its high-pressure phase, in order to remove air from the mixing area and the connected line system. By opening and closing the valve, preferably multiple times (e.g., three times), the air is mechanically expelled, so that less residual air remains in the mixing chamber, which could be entrained during the next filling of the balancing chamber.

[0056] Furthermore, it can be provided that the operating state of the special air separation is not selected if the measured value corresponds to a setpoint or is within a setpoint range or does not exceed or fall below a certain limit value and that, instead, in this case, a normal air separation is carried out, in which the valve is preferably only opened during the dead time of the balance chamber.

[0057] Preferably, the mixing chamber or another mixing area is connected to one or more concentrate lines through which concentrates from concentrate containers enter the mixing chamber. These concentrates can be, for example, an acidic and a basic concentrate. Typically, the mixing chamber is connected to a fresh water connection, in particular an RO water connection, so that the concentrate(s) can be diluted to the desired level. Reference is made to the embodiment according to Figure 1 , which represents a non-limiting example of a dialysis machine of the present invention, wherein Figure 1 neither the conductive elements in the concentrate lines nor the control unit are shown.

[0058] The present invention is preferably used in dialysis machines that do not have an air separation device.

[0059] It should be noted here that the use of the term "a" or "an" does not necessarily imply that exactly one of the elements in question is intended, but also includes the plural. It should also be noted that the use of the plural generally also includes one of the elements in question.

[0060] Further details and advantages of the invention are explained in more detail with reference to an embodiment illustrated in the drawing. They show: Figure 1: a simplified schematic representation of the hydraulic and blood circuit of a dialysis machine; Figure 2: the pressure curve over time during normal air separation; Figure 3: the pressure curve over time during special air separation; and Figure 4: a simplified schematic representation of two concentrate lines of a dialysis machine according to the invention.

[0061] Figure 1shows a hydraulic circuit as well as the extracorporeal blood circuit of a dialysis machine known from the prior art. This structure can be identical or modified in a dialysis machine according to the invention, so that the above statements also apply to the present invention.

[0062] Figure 4 shows the two concentrate lines 40, 50, one of which is in fluid communication with an acidic concentrate located in the container 42, and the other of which is in fluid communication with a basic concentrate located in the container 52. Filters F are located downstream of the containers 42, 52 in the concentrate lines. Between the respective containers 42, 52 and the concentrate pumps 41, 51, which pump the concentrates into the mixing chamber, two sensors in the form of electrically conductive elements S1 and S2, as well as S3 and S4, are located in each of the lines 40, 50.

[0063] The control unit (not shown) measures the conductance values ​​between the sensors S1 and S2 on the one hand and between the sensors S3 and S4 on the other hand.

[0064] If a conductivity value below a threshold is measured one or more times, an alarm is triggered, and the presence of air in the respective line 40, 50 is concluded. In principle, the invention also encompasses the measurement of the conductivity, etc., between a sensor S1 or S2 and S3 or S4, i.e., across the mixing chamber.

[0065] During normal operation, ie when no air is detected in the concentrate lines, the normal air separation is carried out as described above and in Figure 2This air separation occurs by opening the valve V at the dead time t1 of the balancing chamber or the half of the balancing chamber filled with fresh dialysis solution, and then no longer during the balancing chamber cycle BZ.

[0066] However, if the conductive elements or the control unit connected to them detect that excessive air is being drawn in, which may be caused, for example, by the absence of a concentrate container 42, 52 or its empty state, this is detected by the control unit, which then initiates one or more measures.

[0067] In one embodiment, the control unit initiates the following steps: First, the flow rate of the dialysis solution is increased compared to normal dialysis operation, e.g. to a value of 500 ml / min.

[0068] The balance chamber halves are then connected by opening the valves in such a way that a short circuit occurs between the respective balance chamber halves of the two balance chambers or one balance chamber, ie no solution is pumped into line L2.

[0069] Furthermore, an alarm is triggered that is perceptible to the user, indicating, for example, that the acidic concentrate or the alkaline concentrate has been used up.

[0070] Then the normal air separation mode is switched off according to Figure 2 on the special air separation according to Figure 3 This is characterized by the fact that in the high pressure phase (T3) of the balance chamber half filled with fresh dialysis solution, the valve V according to Figure 1once or preferably several times, e.g., three times. In the high-pressure phase, the balancing chamber half is completely filled with liquid. As a result, opening valve V does not result in a flow of air-enriched liquid into the balancing chamber. Rather, opening and closing the valve removes air from the mixing chamber 20, so that when switching back to normal operating mode or normal air separation mode, little or no air enters the balancing chamber. This avoids or at least reduces the likelihood of incorrect balancing.

[0071] Figure 3 shows the pressure curve over time in an arrangement according to Figure 2, where identical points in time and time periods are designated by the same reference symbols, and illustrates that in the high-pressure phase T3, valve V is opened and closed three times, which is indicated by the reference symbol V' and is noticeable by corresponding pressure fluctuations. Preferably, valve V is not opened and closed at dead time t1.

[0072] The Figures 2 and 3 The pressure values ​​specified as well as all other values ​​mentioned in the context of the present invention are exemplary in nature and not restrictive.

[0073] If it is determined that concentrate is present again in the concentrate lines, the special air separation system is activated according to Figure 3 back to normal air separation according to Figure 2 switched.

[0074] If the concentrate supply is restored by reconnecting filled concentrate containers to the concentrate lines, and if no more air has been detected in the concentrate lines for a certain period of time or after, for example, 5 balance chamber cycles, the flushing process is initiated.

[0075] During the flushing process, the hydraulic system, i.e., the dialysis solution circuit, or a portion thereof, is flushed. This area can include the dialysis solution circuit's air separators, filters, the balancing chamber, valves, and all lines connecting the aforementioned elements. The flushing process is performed, for example, by flushing the hydraulic circuit, or a portion of it, twice with ready-to-use dialysis solution.

[0076] Preferably, the patient is separated from the dialysis machine during the rinsing process.

[0077] Once the rinsing process is complete, the alarm message is cleared, the dialysate flow is reduced to the target value and the patient is reconnected so that treatment can continue.

Claims

1. Dialysis machine, which is configured to be equipped with an extracorporeal blood system, comprising a dialysis solution system which is configured to be equipped with a dialyzer, wherein a mixing region, in particular a mixing chamber (20), is provided in which the fresh dialysis solution or a component thereof is located in the operation of the dialysis machine, wherein a concentrate line (40, 50) is in fluid communication with the mixing region, through which concentrate line concentrate can be conducted from a concentrate container (42, 52) into the mixing region, wherein at least two electrically conductive elements (S1, S2, S3, S4) are arranged spaced apart from one another in or at the concentrate line or lines (40, 50), a measuring device is provided which is electrically connected to the conductive elements (S1, S2, S3, S4) and which is configured to measure the conductance or a value correlated therewith between them, and a control unit is provided which is configured to compare the measured value with a desired value, a limit value, or a desired value range, wherein the control unit is configured to initiate a special operating mode of the dialysis machine when the measured value does not agree with the desired value, exceeds or falls below a limit value, or is not in a desired value range, wherein the control unit is configured such that the special operating mode comprises a special air separation differing from normal operation and / or the flushing of the dialysis solution system or a part thereof, characterized in that the control unit is configured such that the flushing of the dialysis solution system or a part thereof only takes place after the special air separation.

2. Dialysis machine in accordance with claim 1, characterized in that exactly one electrically conductive element (S1, S2, S3, S4) is respectively arranged in or at the concentrate line (40, 50) and / or that one or more concentrate lines (40, 50) are provided in or at which a plurality of electrically conductive elements (S1, S2, S3, S4) are arranged.

3. Dialysis machine in accordance with claim 1 or claim 2, characterized in that the conductive elements (S1, S2, S3, S4) are formed by hose connections, and / or in that the conductive elements (S1, S2, S3, S4) consist of metal, preferably of stainless steel and / or titanium, and / or in that the conductive elements (S1, S2, S3, S4) are arranged in or at the same concentrate line (40, 50) or in or at different concentrate lines (40, 50).

4. Dialysis machine in accordance with any one of the preceding claims, characterized in that a concentrate pump (41, 51) is located in the concentrate line (40), and in that the conductive elements (S1, S2, S3, S4) are located upstream or downstream of the concentrate pump (41, 51) in the direction of flow of the concentrate.

5. Dialysis machine in accordance with any one of the preceding claims, characterized in that the control unit is configured to initiate an alarm and / or a special operating mode of the dialysis machine when the measured value does not agree with the desired value, exceeds or falls below a limit value, or is not in a desired value range.

6. Dialysis machine in accordance with claim 1 or claim 5, characterized in that the control unit is configured such that the alarm and / or the special operating mode of the dialysis machine is only initiated when the measured value does not agree with the desired value, exceeds or falls below a limit value, or is not in a desired value range in each case more frequently than a threshold value.

7. Dialysis machine in accordance with any one of the claims 1, 5 or 6, characterized in that the control unit is configured such that the special operating mode comprises the increase of the flow rate of the dialysis solution and / or the bypass circuit of a dialyzer arranged in the dialysis solution system.

8. Dialysis machine in accordance with any one of the preceding claims, characterized in that no air separation means, in particular no air separation chamber, is located in the concentrate line (40, 51) and / or no air separation means is located between the opening of the concentrate line (40, 50) into the mixing region and a balancing chamber of the dialysis solution system.

9. Dialysis machine in accordance with any one of the claims 7 and 8, characterized in that the control unit is configured such that it opens and closes a valve that is preferably in fluid communication with the mixing region once or multiple times in the operating state of the special air separation of the dialysis machine when the balancing chamber half of a balancing chamber of the dialysis solution system in fluid communication with said line is in its high pressure phase.

10. Dialysis machine in accordance with any one of the preceding claims, characterized in that the mixing region, in particular the mixing chamber (20), is connected or connectable to a fresh water connector, in particular to an RO water connector.