BLOOD TREATMENT DEVICE WITH AUTOMATIC SUBSTITUTION VOLUME COMPENSATION

Abstract

A blood treatment device includes an extracorporeal blood circuit, a dialyzer and a dialysis fluid circuit. The extracorporeal blood circuit and the dialysis fluid circuit are separated from each other by a membrane provided in the dialyzer, by which blood can be filtered. At least one substitution solution pump supplies a substitution solution to the extracorporeal blood circuit before and/or after the dialyzer. A control unit calculates a difference or a backlog between an ideal target volume and an actually controlled volume of the supplied substitution solution, and temporarily increases a controlled flow rate of the substitution solution pump under corresponding controlling thereof by a predetermined, fixed percentage which is less than or equal to 5%, until the difference or the backlog between the actually controlled volume and the ideal target volume no longer exists, i.e. the actually controlled volume corresponds to the ideal target volume.

Claims

1. A blood treatment device for use in blood treatment therapies, comprising: an extracorporeal blood circuit, a dialyzer and a dialysis fluid circuit, wherein the extracorporeal blood circuit and the dialysis fluid circuit are separated from each other via a membrane provided in the dialyzer, via which blood can be filtered; at least one substitution solution pump, which is configured to supply a substitution solution to the extracorporeal blood circuit before and/or after the dialyzer; and a control unit which is configured to calculate a difference or a backlog between an ideal target volume set by a user and an actually controlled volume of the supplied substitution solution, and to temporarily increase a controlled flow rate of the substitution solution pump under corresponding controlling thereof by a predetermined, fixed percentage which is less than or equal to 5% until the actually controlled volume equals the ideal target volume.

2. The blood treatment device according to claim 1, wherein the predetermined, fixed percentage by which the flow rate of the substitution solution is increased is at least 1% and at most 5%.

3. The blood treatment device according to claim 1, wherein the predetermined, fixed percentage is set by the control unit depending on the missing volume, so that the predetermined, fixed percentage is set higher when the deviation between the actual volume and the target volume is large, than when the deviation between the actual volume and the target volume is small.

4. The blood treatment device according to claim 1, wherein the control unit is configured to increase the flow rate of the substitution solution pump only if other restrictions do not prohibit this.

5. The blood treatment device according to claim 1, wherein the control unit is configured to calculate the difference or the backlog between the ideal target volume and the actually controlled volume using the course of the flow rate of the at least one substitution solution pump.

6. The blood treatment device according to claim 1, wherein the control unit is configured to adjust the flow rate of the at least one substitution solution pump.

7. The blood treatment device according to claim 6, wherein, when starting or restarting the at least one substitution solution pump, the flow rate slowly increases so that a desired ideal flow rate is reached only after a predetermined, short time period.

8. The blood treatment device according to claim 7, wherein, after reaching the desired ideal flow rate, the flow rate is temporarily increased by the predetermined, fixed percentage in order to slowly reduce the difference or backlog between the actually controlled volume and the ideal target volume, which results from the slow increase of the flow rate at startup or restart, specifically until the actually controlled volume equals the ideal target volume.

9. The blood treatment device according to claim 1, wherein the control unit is configured so that, if the controlled flow rate of the substitution solution pump has to be temporarily reduced, the resulting backlog between the ideal target volume and the actually controlled volume is subsequently reduced or compensated for, by temporarily increasing the controlled flow rate of the substitution solution pump by the predetermined, fixed percentage under appropriate controlling thereof, specifically until the actually controlled volume equals the ideal target volume.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0033] The disclosure is further explained in the following with the help of figures. These show:

[0034] FIG. 1 shows a schematic view of a blood treatment device according to the present disclosure;

[0035] FIG. 2 shows a flow chart illustrating the automatic compensation of a volume of the substitution solution running in the control unit according to the disclosure; and

[0036] FIG. 3 shows a diagram showing a time course of a substitution solution flow rate, according to the present disclosure.

DETAILED DESCRIPTION

[0037] The figures are merely schematic in nature and serve exclusively for understanding the present disclosure. The same elements are marked with the same reference signs.

[0038] FIG. 1 shows a schematic view of an extracorporeal blood treatment device (dialysis device) 2. The blood treatment device 2 is basically configured to be used in both continuous and intermittent blood treatment therapies, in particular renal replacement therapies. The blood treatment device 2 is configured in particular as an acute dialysis machine or an acute dialysis device and is thus essentially prepared for use in intensive care units with predominantly unstable patients. With the blood treatment device 2 of the present disclosure, principally a variety of different blood treatment therapies can be performed (e.g. slow continuous ultrafiltration (SCUF), continuous veno-venous hemofiltration (CVVH), continuous veno-venous hemodialysis (CVVHD), continuous veno-venous hemodiafiltration (CVVHDF), therapeutic plasma exchange (TPE), etc.) as well as dilution modes (e.g., pre-dilution, post-dilution, pre-dilution and post-dilution) and anticoagulation types (e.g., none, heparin, citrate, etc.).

[0039] The blood treatment device 2 basically has an extracorporeal circuit 4, a dialyzer (hemofilter) 6 and a dialysis fluid circuit 8. The extracorporeal circuit 4 and the dialysis fluid circuit 8 are separated by a membrane 10 provided in the dialyzer 6, through which blood can be filtered using a dialysis fluid solution or without using a dialysis fluid solution.

[0040] The extracorporeal circuit 4 comprises an arterial portion 12 and a venous portion 14. In principle, it is provided that the arterial portion 12, in particular one end thereof, is to be connected or attached to an artery of a patient, in particular an intensive care patient. It is also provided that the venous portion 14, in particular one end thereof, is to be connected or attached to a vein of a patient, in particular an intensive care patient.

[0041] The arterial portion 12 has, starting from an arterial end 16 in a blood flow direction towards the dialyzer 6, an arterial pressure sensor 18, an (arterial) blood pump 20, and a dialyzer inlet pressure sensor 22. Starting from the dialyzer 6 in a blood flow direction towards a venous end 24, the venous portion 14 has a venous expansion chamber or air trap 26, a safety air detector 28 and a safety valve 30. A venous pressure can be measured on/behind the venous expansion chamber 26 using a venous pressure sensor 32.

[0042] As shown in FIG. 1, the venous expansion chamber 26 is connected to a substitution solution bag/container 34. A substitution solution pump 36 is provided and configured to pump a substitution solution from the substitution solution bag 34 into the extracorporeal blood circuit 4, in particular into the venous portion 14 thereof (into the venous expansion chamber 26).

[0043] The dialysis fluid circuit 8 has at least one outlet 38 for effluent/used dialysis fluid (dialysate)/another fluid. In principle, the effluent/dialysate/the other liquid can flow through the outlet 38 from the dialyzer 6 to a collecting bag/container 40 for effluent/dialysate/etc. In the outlet 38, an effluent pressure sensor 42, a blood leak detector 44 and an effluent pump 46 are arranged or provided in a direction of flow from the dialyzer 6 to the collecting bag 40.

[0044] As can be further seen in FIG. 1, a further bag/container 48 is provided in addition to the substitution solution bag 34 and the collecting bag 40. Depending on the desired blood treatment therapy to be performed, the bag 48 may contain, for example, a substitution solution/fluid or a dialysis fluid.

[0045] When, for example, a hemodialysis/hemodiafiltration treatment etc. is to be carried out with the extracorporeal blood treatment device 2, i.e. a blood treatment therapy in which dialysis fluid flows through the dialyzer 6 and thus a substance transport from the extracorporeal circuit 4 to the dialysis fluid circuit 8 takes place both by diffusion and convection, then the bag 48 contains dialysis fluid. When a first valve 50 is now opened and both a second valve 52 and a third valve 54 are closed, then the dialysis fluid can be pumped to the dialyzer 6 via a pump 56.

[0046] When, for example, hemofiltration etc. is to be performed with the extracorporeal blood treatment device 2, i.e. a blood treatment therapy in which no dialysis fluid flows through the dialyzer 6 and thus substance transport from the extracorporeal circuit 4 to the dialysis fluid circuit 8 takes place only via convection/filtration, the bag 48 can contain a substitution solution. When the first valve 50 and the second valve 52 are closed and the third valve 54 is opened, the substitution solution can be pumped from the bag 48 into the arterial portion 12 of the extracorporeal circuit 4 (pre-dilution). When the first valve 50 and the third valve 54 are closed and the second valve 52 is opened, the substitution solution can be pumped from the bag 48 into the venous portion 14 of the extracorporeal circuit 4 (post-dilution). When the first valve 50 is closed and the second valve 52 and the third valve 54 are opened, the substitution solution can be pumped from the bag 48 into both the arterial portion 12 and the venous portion 14 of the extracorporeal circuit (pre-dilution and post-dilution). According to the present disclosure, pre-dilution and post-dilution can also be achieved by pumping the substitution solution from the substitution solution bag 34 via the substitution solution pump 36 into the venous portion 14 of the extracorporeal circuit 4 (post-dilution) and simultaneously pumping the substitution solution from the bag 48 via the pump (substitution solution pump) 56 into the arterial portion 12 of the extracorporeal circuit 4 (pre-dilution).

[0047] As shown in FIG. 1, a fluid warmer 58 and a pressure sensor 60 are provided between the pump 56 and the valve assembly consisting of the first valve 50, the second valve 52, and the third valve 54.

[0048] The three bags, i.e. the substitution solution bag 34, the collecting bag 40 and the bag 48, each have load cells attached to them, namely a first load cell 62, a second load cell 64 and a third load cell 66. The first load cell 62 is basically configured to measure or monitor the weight of the substitution solution bag 34. The second load cell 64 is basically configured to measure or monitor the weight of the collecting bag 40. The third load cell 66 is basically configured to measure or monitor the weight of the bag 48.

[0049] The extracorporeal blood treatment device 2 furthermore has a control unit (CPU) 68, which receives information from the sensors provided in the blood treatment device 2 and which controls the actuators provided in the blood treatment device 2. According to the disclosure, this provides software-supported therapy in particular. The control unit 68 receives in particular information from the arterial pressure sensor 18, the dialyzer inlet pressure sensor 22, the safety air detector 28, the venous pressure sensor 32, the effluent pressure sensor 42, the blood leak detector 44, the pressure sensor 60, the first load cell 62, the second load cell 64, the third load cell 66, etc. The control unit 68 controls in particular the blood pump 20, the safety valve 30, the substitution solution pump 36, the effluent pump 46, the first valve 50, the second valve 52, the third valve 54, the pump 56, the fluid warmer 58, etc. Furthermore, the control unit 68 exchanges information with a user interface 70 designed as a display with touch screen. For example, the control unit 68 may be configured to display a warning or an alarm on the user interface 70. Furthermore, information entered by a user/operator on the user interface 70 can be transferred to the control unit 68.

[0050] As already shown in FIG. 1, the present disclosure essentially relates to the driving of the substitution solution pump 36 and the pump 56 (if the pump 56 works as a substitution solution pump). The present disclosure essentially relates to the control by the control unit 68. The control unit 68 can in particular calculate a difference or a backlog between an ideal/optimum target volume of the supplied substitution solution set by a user and an actually controlled volume of the supplied substitution solution. For this purpose, the control unit 68 uses a time curve of the flow rate of the substitution solution pump 36 or of the pump 56.

[0051] When the control unit 68 detects/when the control unit 68 becomes aware (by a corresponding calculation) that there is a difference or backlog between an ideal/optimum target volume set by a user and an actual/concretely controlled volume of the supplied substitution solution, the control unit 68 temporarily increases a controlled flow rate of the substitution solution pump 36 or of the pump 56 by a predetermined, fixed percentage. This means that the flow rate of the substitution solution pump 36 or the pump 56 is set to be higher than a normally required flow rate by a predetermined, fixed percentage. A normally required flow rate is understood to be a flow rate by means of which the ideal/optimum target volume set by a user could be achieved if there were no backlog/difference between the set target volume and the actually controlled volume of the supplied substitution solution.

[0052] The predetermined, fixed percentage can generally be set to a value between 1% and 5%. It may also be provided that the predetermined, fixed percentage is set higher if the deviation between the actual volume and the target volume is large, than if the deviation between the actual volume and the target volume is small. For example, the predetermined, fixed percentage can be set to 1% if the deviation is small and the predetermined, fixed percentage can be set to 5% if the deviation is large. In any case, the percentage set by the control unit (depending on the difference/backlog) is already preset and predetermined.

[0053] According to the disclosure, the flow rate/volume flow of the substitution solution pump 36 or of the pump 56 is increased by the predetermined, fixed percentage until the difference or the backlog between the actually controlled volume and the ideal target volume no longer exists, i.e. the actually controlled volume corresponds (again) to the ideal target volume.

[0054] FIG. 2 shows the course of an automatic volume compensation of a substitution solution according to the disclosure. The control unit 68 first calculates an actually controlled volume of the substitution solution, which is supplied to an extracorporeal circuit 4. The control unit 68 then compares the actually controlled volume supplied to the extracorporeal circuit 4 with a (predetermined) ideal target volume. If the actually supplied volume or actual volume is smaller than the ideal target volume, the control unit increases the flow rate of a substitution solution pump by a predetermined, fixed percentage, which is at most 5%. Then the control unit 68 continues to compare the target volume with the actual volume. Only when the target volume is equal to the actual volume does the control unit 68 reset the flow rate of the substitution solution pump to the initial value/actually required value. The routine shown only ends when the therapy has ended.

[0055] FIG. 3 shows a diagram showing the time course of a substitution solution flow rate Q.sub.controlled of the substitution solution pump 36 or of the pump 56 controlled by the control unit 68. In particular FIG. 3 shows that when starting or restarting the substitution solution pump 36 or the pump 56, the substitution solution flow rate Q.sub.controlled slowly/continuously/linearly increases (from zero) so that a desired ideal flow rate Q.sub.ideal set by a user, which would result in the ideal/optimum target volume being supplied to the extracorporeal circuit 4 (if it was set/available from the start), is only reached at a time t1. According to the present disclosure, the controlled substitution solution flow rate Q.sub.controlled is not (yet) set to the ideal flow rate Q.sub.ideal set by the user at time t1, but continues to increase linearly until a controlled flow rate Q.sub.controlled is reached, which is increased by a predetermined, fixed percentage compared to the ideal flow rate Q.sub.ideal. This is the case in FIG. 3 at time t2. Now, the controlled flow rate is temporarily maintained at a constant value until the volume not yet supplied at the startup (see ‘−V’ in FIG. 3), i.e. the backlog or difference, has been completely compensated (see ‘+V’ in FIG. 3). This is the case in FIG. 3 at time t3. At time t3 the controlled flow rate Q.sub.controlled is finally set to the ideal flow rate Q.sub.ideal.