Abstract
A device and method of producing dialysis liquid for extracorporeal blood treatment. The device includes a main line for supplying water. An acidic and a basic fluid are introduced in specific dosages. The dosages are set by a control and regulation unit as a function of a chemical and/or physical parameter of the water/fluid mixture. The chemical and/or physical parameter is detected by a measuring device arranged at a section of the main conduit situated downstream of the introduction points for the acidic fluid and for the basic fluid. The control and regulation unit controls introduction of the acidic fluid and basic fluid so that only one of the acidic and basic fluids is introduced into the main conduit over a predetermined period or a predetermined interval. Delivery and introduction of the basic fluid and acidic fluid take place alternately.
Claims
1. A method for producing a dialysis liquid for use in extracorporeal blood treatment in a device for extracorporeal blood treatment, comprising the steps of: conveying water via a main line; conveying a basic fluid and introducing the basic fluid into the main line at a first introduction point formed as a first Venturi mixer; conveying an acidic fluid and introducing the acidic fluid into the main line at a second introduction point formed as a second Venturi mixer or at the first introduction point formed as the first Venturi mixer, the water, the basic fluid and the acidic fluid forming a water/fluid mixture; measuring a first physical and/or chemical parameter of the water/fluid mixture with a first measuring device, the first physical and/or chemical parameter comprising at least one of the water, the acidic fluid and the basic fluid; and adjusting a delivery rate for the water, the acidic fluid and/or the basic fluid by a control and regulation unit as a function of a measured value detected, wherein measurement of the first physical and/or chemical parameter is performed with the first measuring device located at a section of the main line downstream of the second introduction point for the acidic fluid and of the first introduction point for the basic fluid; and the control and regulation unit at least temporarily controls introduction of the acidic fluid and/or the basic fluid such that over a predetermined period or a predetermined interval only one of the acidic fluid and the basic fluid is introduced into the main line, wherein delivery and introduction of the basic fluid and delivery and introduction of the acidic fluid takes place alternately.
2. The method according to claim 1, wherein delivery and introduction of the basic fluid and delivery and introduction of the acidic fluid take place in continuous alternating fashion.
3. The method according to claim 1, wherein, when an adjustment of a delivery rate of one the basic fluid and acidic fluid occurs, a delivery rate of the other of the basic fluid and acidic fluid is maintained as set before said adjustment, or delivery of the other of the basic fluid and acidic fluid is paused.
4. The method according to claim 1, wherein the water/fluid mixture is moved past the device for extracorporeal blood treatment when changing or newly setting at least one target value until the at least one target value is reached for a first time at least once.
5. The method according to claim 4, wherein, in a case in which for reaching the at least one target value, a defined period of time is exceeded and/or a delivery rate is set which exceeds a defined limit value, a warning is issued at the device for extracorporeal blood treatment.
6. The method according to claim 1, further comprising: measuring a second physical and/or chemical parameter of the water/fluid mixture with a second measuring device, the second physical and/or chemical parameter comprising at least one of the water, the basic fluid and/or the acidic fluid, and the second measuring device being arranged on the main line directly downstream of the first measuring device, wherein a warning is issued at the device for extracorporeal blood treatment when there is a deviation between a first measurement of the first physical and/or chemical parameter and a second measurement of the second physical and/or chemical parameter that exceeds a defined limit value.
7. The method according to claim 1, wherein the water/fluid mixture is intermixed with at least one mixing device provided in addition to the first Venturi mixer or the second Venturi mixer.
8. The method according to claim 7, wherein the at least one mixing device is a chamber of a chamber-based balancing system and a physical and/or chemical target value of the water/fluid mixture is defined such that it can be realized mathematically within a unit of time which corresponds at most to one switching process of the chamber.
9. The method according to claim 1, wherein addition of the basic fluid and the acidic fluid is coded.
10. The method according to claim 1, wherein the first physical and/or chemical parameter of the water/fluid mixture is measured with only one of the basic fluid and the acidic fluid, and based thereon, a first dosage or delivery rate of said one of the basic fluid and the acidic fluid is determined, whereupon introduction of said one of the basic fluid and the acidic fluid is interrupted and the other of the basic fluid and the acidic fluid is introduced instead, wherein the first physical and/or chemical parameter of the water/fluid mixture is measured with only the other of the basic fluid and the acidic fluid, and based on this measurement, a second dosage or delivery rate of the other of the basic fluid and the acidic fluid is determined and, finally, the one of the basic fluid and the acidic fluid is introduced continuously with the first dosage or delivery rate, and the other of the basic fluid and the acidic fluid is introduced continuously with the second dosage or delivery rate.
11. (canceled)
12. A device for producing a dialysis liquid containing water, a basic fluid and an acidic fluid, for use in extracorporeal blood treatment, the device comprising: a main line for supplying the water during which the basic fluid and the acidic fluid are introduced, the basic fluid being introduced at a first dosage by a first Venturi mixer arranged at a first introduction point and the acidic fluid being introduced at a second dosage by a second Venturi mixer arranged at a second introduction point or by a first Venturi mixer arranged at a first introduction point, wherein each of the first dosage and the second dosage is set by a control and regulation unit as a function of a first chemical and/or physical parameter of the water/fluid mixture, and the first chemical and/or physical parameter is detected by a first measuring device wherein the first measuring device is arranged at a section of the main conduit which is positioned downstream of the first introduction point and the second introduction point, and the control and regulation unit at least temporarily controls introduction of the acidic fluid and the basic fluid in such a manner that only one of the acidic fluid and the basic fluid is introduced into the main conduit over a predetermined period or a predetermined interval, wherein the control and regulation unit is adapted to control delivery and introduction of the basic fluid and delivery and introduction of the acidic fluid such that delivery and introduction of the basic fluid and delivery and introduction of the acidic fluid takes place alternately.
13. The device according to claim 12, wherein the basic fluid is conveyed to the main line by negative pressure generated by the first Venturi mixer and/or the acidic fluid is conveyed to the main line by negative pressure generated by the second Venturi mixer.
14. The device according to claim 12, wherein introduction of the acidic fluid and/or introduction of the basic fluid is effected by at least one controllable valve.
15. The device according to claim 12, further comprising a second measuring device directly downstream of the first measuring device, the second measuring device adapted to detect a second physical and/or chemical parameter of the water/fluid mixture flowing through the main line.
16. The device according to claim 12, wherein the device comprises, in addition to the first Venturi mixer and second Venturi mixer, at least one mixing device arranged downstream of the first measuring device and the second measuring device.
17. A device for performing the method according to claim 1.
18. The device according to claim 12, wherein: the control and regulation unit is configured to control introduction of the acidic fluid and/or basic fluid during a control operation such that over a predetermined period or a predetermined interval only one of the acidic fluid and the basic fluid is introduced into the main line; and the control and regulation unit is configured to set a continuous introduction of the acidic fluid and/or of the basic fluid as soon as the control operation is completed.
19. The device according to claim 14, wherein at least one pressure sensor is provided upstream of the at least one controllable valve for determining a type of concentrate supply fluid-connected to the device for extracorporeal blood treatment.
20. The device according to claim 19, wherein, when a concentrate canister is determined as the type of concentrate supply fluid-connected to the device for extracorporeal blood treatment, the control and regulation unit is adapted to determine a filling level of a concentrate contained in the concentrate canister by communication with the at least one pressure sensor.
21. The device according to claim 20, wherein the device for extracorporeal blood treatment is adapted to issue a haptic, acoustic or visual warning signal if the filling level of the concentrate contained in the concentrate canister falls below a previously set threshold value.
22. The device according to claim 12, wherein the control and regulation unit is adapted to control delivery and introduction of the basic fluid and delivery and introduction of the acidic fluid such that delivery and introduction of the basic fluid and delivery and introduction of the acidic fluid take place in continuous alternating fashion.
Description
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0062] The invention is described in more detail below using preferred exemplary embodiments with reference to the attached drawings.
[0063] FIG. 1A shows a schematic representation of a first device according to the invention.
[0064] FIG. 2A shows a schematic representation of a second device according to the invention.
[0065] FIGS. 1B and 2B show variations of the first and second device according to the invention, respectively.
[0066] FIG. 3 shows a diagram of a pulsating pump delivery from the state of the art.
[0067] FIG. 4 shows a diagram illustrating an example of the dosing of the basic or acidic fluid according to an aspect of the invention.
[0068] FIG. 5 shows a schematic representation of the method according to an aspect of the invention.
[0069] FIG. 6 shows a schematic representation of a first metering mode according to the invention.
[0070] FIG. 7 shows a schematic representation of a second metering mode according to the invention.
[0071] FIG. 8 shows a schematic representation of a mode, according to the invention, of adapting the delivery rate.
[0072] FIG. 9 shows a diagram of a dosing/addition method and a diagram of the recorded measurement signal according to an aspect of the invention.
[0073] FIG. 10 shows a diagram of a coded dosing/addition method and a diagram of the recorded measurement signal according to an aspect the invention.
[0074] FIG. 11 shows a schematic representation of a third device according to the invention.
[0075] FIG. 12 shows a diagram illustrating a time course of pressure according to an aspect of the invention.
[0076] FIG. 13 shows a schematic representation for determining a filling level of a canister that provides one of the concentrates used for producing a dialysis liquid.
DETAILED DESCRIPTION
[0077] FIG. 1A shows a first embodiment, according to the invention, of the device for producing a dialysis liquid. A (first), optionally adjustable pump 1 delivers/sucks water from a reservoir 2, which may be a container such as a canister or a continuous source, via a main line 3 towards pump 1. A first Venturi mixer 4, which is located at a first introduction point in the main line 3, conveys a basic fluid from a first storage container 5, which may be a canister or a cartridge, via a first supply line 6 to the main line 3, where the first supply line 6 opens into the main line 3 at first introduction point. A second Venturi mixer 7, which is arranged at a second introduction point in the main line 3, conveys an acidic fluid from a second storage container 8, which may be a canister among other things, via a second supply line 9 to the main line 3, where the second supply line 9 opens into the main line 3 at the second introduction point. The addition of the basic fluid and the acidic fluid in the water is done by operating two controllable valves 10, 11, which are arranged accordingly in the first supply line 6 and the second supply line 9. Downstream of the introduction point (orifice point) of the supply line 6 in the main line 3, there is arranged a measuring device 12, which may be a conductivity probe among other things, preferably a conductivity probe with temperature sensor for temperature-compensated conductivity determination. The measuring device 12 measures at least one physical and/or chemical parameter of the passing water/fluid mixture. A control and regulation unit 13 processes the signals of the measuring device 12 and controls the pump 1 as well as the valves 10, 11.
[0078] FIG. 2A shows a second embodiment according to the invention of the device for the production of a dialysis liquid. The basic structure and the reference numerals from the first embodiment remain unchanged, so that in the following only differences between the first and second embodiment are discussed. Instead of the Venturi mixers 4, 7, a single Venturi mixer 4 conveys the basic fluid and the acidic fluid to the main line 3, where the supply line 6 and the supply line 9 converge to a common line section 15 which opens into the main line 3 at a single introduction point via the single Venturi mixer 4 (i.e., the first and the second introduction point correspond to each other). The (controllable) valve 10 is provided at the supply line 6 and the (controllable) valve 11 is provided at the supply line 9. The addition of the basic fluid and the acidic fluid to the water is done by operating (opening and closing) the valves 10 and 11. Downstream of the point where the common line section 15 opens into the main line 3, the measuring device 12 is arranged. A control and regulation unit 13 processes the signals from the measuring device 12 and controls the pump 1 and the valves 10 and 11.
[0079] The dosing in the second embodiment is performed in interaction with the valves 10, 11 so that when one of the fluids is to be conveyed and introduced, the valve on the supply line of the fluid to be conveyed is open. The valve on the other supply line remains closed during this time. If both fluids are to be added in parallel, this can also be done via the corresponding control of the valves.
[0080] FIG. 1B and FIG. 2B show variations of the devices shown in FIG. 1A and FIG. 2A which differ from these in that the pump 1 is located to be upstream of the introduction point(s).
[0081] FIG. 3 shows a diagram illustrating an addition quantity (volume) as a function of time (t). This is a pulsating or intermittent conveyance from the state of the art in which the addition quantities of the basic or acidic components are not supplied evenly but in pulsed fashion.
[0082] FIG. 4 shows a diagram illustrating an example of the dosage or setting of the delivery rate of the basic or acidic fluid. For this purpose, the corresponding switchable valve 10 or 11 is opened until an upper concentration value (conductivity value) +ε is determined by the measuring device 12, and the valve 10 or 11 is closed when the upper concentration value +ε is reached. Then the concentration value (or the conductivity measuring signal) LF drops until a lower concentration value −ε is reached, whereupon the valve 10 or 11 is opened again. The mean value between the upper and lower concentration value +ε, −ε corresponds to the concentration target value, i.e. the concentration with which the corresponding fluid in the fresh dialysis liquid should be present. The control procedure described here will be repeated and the associated data will be stored until the data recorded in this regard (e.g. delivery rate of pump 1, opening and closing times of the valves 10 or 11, concentration values, etc.) allow to determine optimum opening and closing times t.sub.Open, t.sub.Closed of the valves 10 or 11 and based on this the delivery rate can subsequently be controlled (i.e. can be set without further feedback of measurement data). The controller used can be a multi-point controller, in particular a two-point controller, P controller, PI controller, PID controller, fuzzy controller, adaptive controller, hybrid controller and/or a controller based on artificial neural networks.
[0083] FIG. 5 shows a schematic representation of the (calibration) method according to an aspect of the invention. After the method has been started, at least one physical and/or chemical target value for a water/fluid mixture consisting of water, the basic fluid and/or acidic fluid is first defined, and the corresponding delivery rates of the water, of the basic fluid and/or of the acidic fluid are set. The setting can be done by calculation, analytical determination or another definition. This corresponds to method step S1. Water is then pumped at the set delivery rate. This corresponds to method step S2. Subsequently, the basic fluid and the acidic fluid are conveyed either in a mode M1 or in a mode M2 and introduced into the water. The modes M1 and M2 are described in more detail in the descriptions of FIG. 6 and FIG. 7 below.
[0084] FIG. 6 shows a schematic representation of a first mode, according to the invention, of the metering M1 in which the basic fluid and the acidic fluid are alternately/serially pumped and added. Starting from the method step S2, which has been explained in more detail above in the description of FIG. 5, the conveying of only a first one of the basic and acidic fluids (hereinafter first fluid) is started and introduced into the conveyed water. The delivery can be carried out with a set delivery rate for the first fluid, in particular with the delivery rate set in step S1. This corresponds to method step S3.1. Subsequently, at least one physical and/or chemical parameter of the water/fluid mixture, consisting of water and the first fluid or containing these, is measured and the measured value is compared with at least one defined target value provided for the water/fluid mixture and defined in particular in step S1. This corresponds to the method step S3.2. In the subsequent method step S4.1a, upon reaching the at least one target value, the delivery of only the first fluid is stopped and the delivery exclusively of the second one of the basic and acidic fluids (hereinafter second fluid) is started and introduced into the water. The delivery can be carried out with a set delivery rate for the second fluid, in particular with the delivery rate set in step S1. Then, at least one physical and/or chemical parameter of the water/fluid mixture, which consists of water and the acidic fluid or contains these, is measured and the measured value is compared with the at least one defined target value for the water/fluid mixture, in particular defined in step S1, which corresponds to the method step S4.2a. In the subsequent method step S4.3a, upon reaching the at least one target value, the delivery of the second fluid is interrupted and the method is continued with step S3.1 or the steps are repeated from step S3.1 onwards. If the delivery rate for the water, the first fluid and/or the second fluid is to be changed, this can be done by measurement control at any point in time during the method, in which only that component is conveyed whose delivery rate is to be changed.
[0085] In the case in which the two fluids are alternately delivered, it should be noted that the corresponding target values for their concentration are each multiplied according to the ratio of the addition time or valve opening time of the individual fluids in such a way that the set addition quantity, averaged over time, leads to the desired concentration of the fluid in the fresh dialysis fluid. For example, if the valve opening time of the basic fluid is the same as the valve opening time of the acidic fluid, the corresponding target values are doubled.
[0086] FIG. 7 shows a schematic representation of a second mode, according to the invention, of the metering M2 in which the basic fluid and the acidic fluid are delivered and added in parallel in a time-staggered manner. The mode M2 is similar to the mode M1 described above up to and including step S3.2. Starting from method step S3.2, in the subsequent step S4.1b the delivery of the first fluid will be maintained at the previously set delivery rate and the last measured parameter is kept as a reference value if the at least one target value is reached for the water/fluid mixture which consists of water and the first fluid or contains it, whereupon the delivery of the second fluid will be started and the latter is then introduced into the water. Here, the delivery can be performed at a set delivery rate for the second fluid, especially the delivery rate adjusted in step S1. Subsequently, at least one physical and/or chemical parameter of the water/fluid mixture, consisting of water and both fluids or containing them, is measured and the measured value is compared with at least one defined target value or the previously defined reference value, in particular defined in step S1, which corresponds to method step S4.2b.
[0087] FIG. 8 shows a schematic representation of a mode M3, according to the invention, of the delivery rate adaptation. Starting from M2, the delivery rate of a first one of the basic and acidic fluids (hereinafter first fluid) is to be changed. For this purpose, following the mode M2, first the conveying of the second one of the basic and acidic fluids (hereinafter second fluid) is paused, which corresponds to step S5. The first fluid is then delivered at a newly set delivery rate and introduced into the water/fluid mixture. This corresponds to step S6. Subsequently, step S7 is executed, in which at least one physical and/or chemical parameter of the water/fluid mixture, consisting of water and the first fluid or containing it, is measured and compared with the new target value based on the changed delivery rate. Subsequently, when the new target value is reached, the newly set delivery of the first fluids is continued and the delivery of the second fluid is resumed and the latter is introduced into the water. This corresponds to step S8. Subsequently, at least one physical and/or chemical parameter of the fluid mixture, consisting of water and the two fluids or containing them, is measured and compared to at least one defined target value, which corresponds to step S9. The method can then be continued in the mode M1, M2 or M3. Alternatively, in step S5 the conveying of the second fluids can be continued while maintaining the set delivery rate. The steps S7 and S8 are omitted in this alternative.
[0088] FIG. 9 shows a diagram of an exemplary dosage/addition method and a diagram of the recorded measurement signal according to an aspect of the invention. In the upper diagram, the bars in the intervals I1, I3 and I5 represent the dosed volumes of the basic fluid. The bars in the intervals I2, I4 and I6 represent the dosed volumes of the acidic fluid. This diagram shows that the dosing of the fluids is performed in a pulsating manner, i.e. the fluid volumes are added intermittently to the first fluid.
[0089] In the diagram below, the conductivity of a water/fluid mixture consisting of water, the basic and/or acidic fluid measured at a measuring device is plotted as a function of time. The basic fluid has a lower conductivity than the acidic fluid. So when a volume of acidic fluid is measured at the measuring device, the conductivity signal is higher than when a volume of basic fluid is measured at the measuring device. Therefore, in the intervals in which the acidic fluid is added in pulsating fashion, the measured conductivity is greater than in the intervals in which the basic fluid is added.
[0090] FIG. 10 shows a diagram of a coded dosage/addition method and a diagram of the recorded measurement signal according to an aspect of the invention. In the upper diagram, the bars marked with an arrow represent the dosed volumes of the basic fluid and the bars without a mark represent the dosed volumes of the acidic fluid. The coding, as described here, is not limited to the alternating delivery of the basic fluid and acidic fluid (e.g. in mode M1), since the high conductivity (“+1”) can also be achieved by maintaining the delivery of the basic fluid when the acidic fluid is added. The signal or reading of the basic fluid can be encoded according to the Barker code with “−1” and the signal or reading of the acidic fluid can be encoded according to the Barker code with “+1”. The diagram shows the dosage according to a Barker code having a length of eleven with “+1+1+1−1−1−1+1−1−1+1−1” or “SK SK SK BK BK BK SK BK BK SK BK”. Here, “SK” may also be “SK+BK” (e.g. in mode M2).
[0091] In the diagram below, the conductivity of a fluid mixture consisting of water, the basic and/or acidic fluid measured at a measuring device is plotted as a function of time. The measured signal corresponds to the Barker code having a length of eleven with “+1+1+1−1−1−1+1−1−1+1−1” or “SK SK SK BK BK BK SK BK BK SK BK”, where “SK” may also be “SK+BK” (e.g. in mode M2).
[0092] The signal resulting at the measuring device can be processed or evolved by appropriate mathematical means, whereupon conclusions can be drawn about the addition quantities of the individual components. The total signal, for example the total conductivity, can additionally be determined by mathematical averaging. According to this principle, other codings, such as those used in communications engineering, are also conceivable.
[0093] From the signal dynamics it can also be concluded whether the functionality of the measuring equipment is still given. Since a calibration to the individual fluids is carried out at the beginning of a conditioning phase, an expected value for a difference and a ratio of the two parameters of the fluids, for example conductivity, is known. Through the mathematical evolution, both measured values, i.e. for a mixture made up of the basic and acidic fluid, can be constantly calculated and set in relation to each other. From the comparison with the original ratio it can be concluded that the measuring device is still functioning. With this method it is also possible to save an existing additional measuring device in state of the art devices.
[0094] FIG. 11 shows a third embodiment according to the invention of the device for the production of a dialysis liquid. The basic structure and the reference numerals from the first embodiment remain unchanged, so that in the following only differences between the first and third embodiment are discussed. In addition to the first embodiment, a pressure sensor 16, 17 is provided respectively upstream, but preferably at the same height of each valve 10, 11. The pressure sensors 16, 17 can be used for determining the type of concentrate supply, i.e. if a canister, a cartridge or a central concentrate supply is actually fluid-connected to the device for extracorporeal blood treatment. In case the first storage container 5 and the second storage container 8 are concentrate canisters, the pressure sensors 16, 17 measure a pressure of ≤0 mmHg when the valves 10, 11 are closed as there is no positive pressure within the canister. If however a cartridge is used as concentrate supply, a positive pressure of approximately 300 mmHg exists under same valve conditions since the cartridge is already pressurized during manufacturing. With a central concentrate supply, the pressure might be even higher and at about 900 mmHg. When the type of concentrate supply is determined by means of the pressure sensors 16, 17, controller properties such as the P-, I- and/or D-part of the controller of the control and regulation unit 13 can be adjusted for dosage of the acidic and basic liquid. Thus, by processing the signals of the measuring device 12 and the pressure sensors 16, 17, the control and regulation unit 13 controls the pump 1 as well as the valves 10, 11.
[0095] In case a concentrate canister is used as concentrate supply, a filling level h.sub.F of the concentrate contained in the canister can be determined by means of the pressure sensors 16, 17 by evaluating the pressure over time as shown in FIG. 12. After opening of the valve 10, 11 as shown in FIG. 12 the pressure measured deflects until the valve 10, 11 is closed again. After closing of the valve 10, 11 the previous deflection decays and the pressure signal is stabilized. The stabilized or steady state pressure shown in form of dotted line borders in FIG. 12 is preferably averaged (average or median) and referred to as p.sub.rel. By using the basic equation of hydrostatics (1), the following relationship between p.sub.rel and the capillary rise h.sub.S, which is defined as the height between the filling level h.sub.F of the concentrate contained in the canister and the pressure sensor 16, 17, can be drawn:
[00001]
[0096] In this context, ρ stands for the almost constant density and g stands for the gravitational acceleration, which are both known variables. After calculation of the capillary rise h.sub.S based on the previously mentioned basic equation of hydrostatics (1), the filling level h.sub.F of the concentrate contained in the canister can be calculated according to the following equation:
h.sub.F=h.sub.ges−|h.sub.g| (2)
[0097] With reference to FIG. 13 the above-mentioned equation (2) for calculating the filling level h.sub.F of the concentrate contained in the canister is explained. According to FIG. 13, the filling level h.sub.F of the canister is determined by use of the total height h.sub.ges consisting of the capillary rise h.sub.S and the filling level h.sub.F of the canister. By subtracting the previously calculated capillary rise h.sub.S from the total height h.sub.ges, a conclusion can be drawn over the actual filling level h.sub.F of the concentrate contained in the canister. In this way, it can be determined whether the canister of the connected fluid is empty and needs to be replaced.
