METHOD FOR DETERMINING AT LEAST ONE PARAMETER OF AN EXTRACORPOREAL BLOOD CIRCUIT AS WELL AS APPARATUSES

Abstract

A method for determining at least one parameter of an extracorporeal blood circuit includes the steps of filling an extracorporeal blood circuit, e.g., encompassing a medical functional device, a treatment device and/or a blood tube set, by introducing a fluid, and detecting a volume of the introduced fluid which is required for filling the extracorporeal blood circuit by a detection device. A control device, a treatment apparatus, a computer readable storage medium, a computer program product as well as a computer program are also described.

Claims

1. A method for determining at least one parameter of an extracorporeal blood circuit or a component thereof, comprising: filling the extracorporeal blood circuit by introducing a fluid; and one of detecting, determining and calculating a size of a volume of the introduced fluid which is required for filling at least one of the extracorporeal blood circuit and a predetermined section thereof.

2. The method according to claim 1, wherein the filling serves as a preparation of the extracorporeal blood circuit.

3. The method according to claim 1, further comprising: processing a value of the detected fluid volume for maintaining the at least one parameter.

4. The method according to claim 1, wherein the volume of the fluid is a cumulative volume.

5. The method according to claim 1, further comprising: conveying the fluid through the at least one of the extracorporeal blood circuit and the predetermined section thereof by a blood pump having at least one of a constant and a predetermined flow; determining a point in time when the fluid appears at a first sensor of the extracorporeal blood circuit as a first point in time; determining a point in time when the fluid appears at a second sensor of the extracorporeal blood circuit as a second point in time; determining a time difference between the first point in time and the second point in time; wherein the one of detecting, determining and calculating of the size of the volume of the introduced fluid comprises multiplying the time difference with the constant flow of the blood pump.

6. The method according to claim 5, wherein at least one of the first sensor and the second sensor are optical sensors.

7. The method according to claim 5, wherein at least one of the first sensor and the second sensor are sensors for detecting the fluid by one of ultrasound, acoustic and temperature measurements.

8. The method according to claim 1, wherein the detecting takes place by a detection device which one of comprises and is connected to at least one recognition device for recognizing a fluid or a fluid condition; wherein the recognition device is chosen from a group consisting of level detectors, air detectors, optical detectors, ultrasound detectors, sound detectors and combinations thereof.

9. The method according to claim 1, wherein a value of the volume of the fluid is detected by rotor turns of a conveying device for conveying the fluid.

10. The method according to claim 1, wherein the size of the volume of the fluid is detected by a weight reduction of a source of the fluid caused by the filling.

11. The method according to claim 1, further comprising: comparing the determined parameter with parameters of a multitude of utilizable medical functional devices to identify a utilized medical functional device.

12. The method according to claim 1, further comprising: comparing the determined parameter with parameters of a multitude of utilizable treatment devices to identify a utilized treatment device.

13. The method according to claim 1, further comprising: defining at least one of a minimum priming or flush volume and a maximum priming or flush volume of the extracorporeal blood circuit by the determined parameter.

14. The method according to claim 13, wherein the minimum flush volume for flushing the extracorporeal blood circuit for preparation of a treatment method is defined by the following mathematical function:
V_min=a*V_Set+b*V_Dial where V_min is the minimum flush volume when preparing the treatment method; V_Set is a volume of a medical functional device; V_Dial is a volume of a treatment device; and a and b are constants.

15. The method according to claim 14, wherein a is a number in a range from 1 to 3.

16. The method according to claim 14, wherein b is a number in a range from 2 to 5.

17. The method according to claim 1, further comprising: defining one of control and flow rates of a treatment method one of taking into account and depending on the determined parameter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0103] FIG. 1 shows a schematic illustration of an extracorporeal blood circuit which may be prepared for its use by means of the method according to the present invention, as well as of a dialysate circuit.

[0104] FIG. 2 illustrates the filling volume of different dialyzers and their identifiability by means of the method according to the present invention.

[0105] FIG. 3 shows a schematic illustration of yet another extracorporeal blood circuit, which can be prepared for its use or for a concluding rinsing by means of the method according to the present invention.

DETAILED DESCRIPTION

[0106] FIG. 1 schematically shows an extracorporeal blood circuit 1000 as well as, in outlines, a dialysate circuit 2000 of a treatment apparatus 3000, for example a hemodiafiltration machine.

[0107] The extracorporeal blood circuit 1000 comprises, is connected to or at least in sections integrated into a medical functional device 100, for example a (disposable) blood cassette.

[0108] The functional device 100 is functionally coupled to the treatment apparatus 3000 and functionally interacts with the pump drives, actors and sensors of the treatment apparatus 3000 which is only outlined in FIG. 1. The pump drives, actors and sensors of the treatment apparatus 3000 functionally interact with a control and/or regulating device 27 of the treatment apparatus 3000. They may be in signal connection with the control and/or regulating device.

[0109] The extracorporeal blood circuit 1000 is connected to a treatment device 200, for example a dialyzer or a blood filter.

[0110] In or at the extracorporeal blood circuit 1000, a blood pump 11 as well as a substitute pump 17 are arranged. The blood pump 11 and the substitute pump 17 may convey blood or substitute in a later occurring treatment method.

[0111] The blood pump 11 and/or the substitute pump 17 may be utilized in the sense of the method according to the present invention as conveying device(s) for conveying the fluid to fill the extracorporeal blood circuit 1000. The same applies to a pump of the dialysate circuit; the pump is not illustrated in FIG. 1.

[0112] The extracorporeal blood circuit 1000 comprises an arterial air bubble detector 15 (art. ABD). IL further comprises a venous air bubble detector 25 (ven. ABD). For example, the venous air bubble detector 25 may be utilized in the extracorporeal blood circuit 1000 as a recognition device for recognizing a filling state.

[0113] The method according to the present invention serves in some embodiments according to the present invention to determine the fluid volume through the treatment apparatus 3000, the filling volume being required for filling the extracorporeal blood circuit 1000, i.e. the blood side of the line system.

[0114] In certain embodiments of the method according to the present invention, the volume of the fluid, which was introduced for filling the extracorporeal blood circuit 1000, is detected which is required for triggering a level detection (for example, at a venous chamber 26) or a message by the venous air bubble detector 25. The detected volume may be defined, e.g., by determining the required rotor turns of the blood pump 11 and/or of the substitute pump 17, or by weighing a liquid bag with fresh flushing/substitute solution. The detected volume may be multiplied with a factor in order to specify or adjust the required flush volume.

[0115] If the liquid level drops again at the detection point, i.e. at the detection position or at the recognition device, during filling, for example because remaining air dissolves out of the treatment device 200, the volume required for raising the level again may be added to the already detected volume. The further use of the such determined cumulative volume may hereby advantageously increase the accuracy of determining the of the detected volume.

[0116] The detected volume is in certain embodiments used for identifying a utilized blood tube set. Identifying the blood tube set may for example take place by means of a comparative table in which typical filling volumes for different disposable configurations or blood tube/blood filter combinations are recorded.

[0117] The comparative table is in some embodiments according to the present invention saved within the control and/or regulating device 27 in a data storage or may be saved in it according to the present invention.

[0118] The control and/or regulating device 27 comprises in some embodiments according to the present invention a device for evaluating measurement data and calculating a filling volume, in particular the cumulative filling volume from the measurement data. It may additionally comprise a device for comparing the calculated filling volume with the data from the comparative table, further a device for allocating the calculated filling volume to certain predefined blood tube sets from the comparative table. The above-mentioned devices may be combined in one single device.

[0119] Thus, for example different blood tube systems for, e.g., pediatric dialysis and dialysis for adults, or different treatment methods (single-needle/double-needle) may be advantageously easily distinguished. Depending on the identified type of disposable, treatment modalities may be blocked and/or treatment parameters may be restricted at the treatment apparatus, in particular automatically and without the involvement of the supervisor.

[0120] In further embodiments, the detected volume is used for identifying the utilized treatment device 200, for example a utilized dialyzer.

[0121] For refinement of the identification, further (supplemental) characteristic features which are available to the treatment apparatus can be taken into account (for example, a filling volume on the dialysate side, flow resistances on the blood and/or dialysate side, the transmembrane pressure and the like).

[0122] Further, FIG. 1 shows an arterial blood tube clamp 29 and a venous blood tube clamp 31.

[0123] FIG. 2 shows different filling volumes V (in ml) of a first extracorporeal blood circuit for a single-needle treatment (associated values are marked with squares), of a second extracorporeal blood circuit for a double-needle treatment (associated values are marked with rhombi), and of a third extracorporeal blood circuit for a blood cassette (associated values are marked with crosses).

[0124] The filling volume of the first blood circuit (squares) is 166 ml. The filling volume of the second blood circuit (rhombi) is 130 ml. The filling volume of the third blood circuit (crosses) is 97 ml. These specifications each apply to the blood circuit as long as it is not connected with a blood filter.

[0125] FIG. 2 shows how the whole filling volume of the above-named blood circuits increases, and increases in different ways, as soon as they are connected with one of the filters A, B, C, D, E, F or G.

[0126] It is therefore well recognizable from FIG. 2 that knowledge of the filling volume of a concrete blood circuit already exhibits with which filter it is connected at the moment of its filling in the sense of the present invention.

[0127] In certain embodiments of the method according to the present invention, the method encompasses defining parameters or parameter values for the method control in the subsequent treatment, e.g., defining maximum/minimum admissible pump rates (small dialyzers have smaller recommended blood flows than larger ones), automatically defining reinfusion volumes, or the like.

[0128] Table 1, which reflects this, is hereafter shown for the minimum flow min_Flow and the maximum flow max_Flow for the blood filters A to G as mentioned above, which have different filling volumes or blood volumes.

TABLE-US-00001 TABLE 1 blood filter blood volume min_Flow max_Flow A 32 50 200 B 74 150 400 C 95 200 500 D 116 250 600 E 97 150 400 F 118 200 500 G 138 300 600

[0129] It is thus recognizable for the person skilled in the art that the knowledge of the utilized filter type, which may be determined by means of the method according to the present invention, can also be used for controlling the treatment apparatus during a subsequent treatment. Thus, a minimum or maximum flow (rate) (min_Flow or max_Flow), which depends on the type of blood filter, can automatically be adjusted.

[0130] FIG. 3 shows a schematic illustration of yet another extracorporeal blood circuit 1000. The method according to the present invention can be executed in the following way, by means of example. Hereby it is assumed, that the blood treatment device 200 is a dialyzer.

[0131] When a very schematically illustrated patient 35 has been connected to an extracorporeal blood circuit, blood pump 11 is started with a constant blood flow Q_B (ml/min). The blood passes a first sensor 37 and the arterial blood tube clamp 29 and into the extracorporeal blood circuit.

[0132] The entering blood is thereby recognized by a first sensor 37 (e.g. an optical sensor or an optical sensor for measuring at least one blood parameter) at a first point of time t1 (sec).

[0133] At a second point of time t2 (sec), the blood is recognized in the venous line by a second sensor 39, e.g. an optical sensor, once it has arrived there. The detection of blood by means of the second sensor may for example take place by infrared transmission measurement.

[0134] In some embodiments according to the present invention the second sensor 39 may be coupled with an air bubble detection device or may be provided therewith in one common assembly.

[0135] The second sensor 39 is in certain embodiments arranged upstream of the venous blood tube clamp 31. In some embodiments according to the present invention it is arranged downstream of the venous chamber 26 or the venous bubble chamber.

[0136] The volume V_Set of the entire extracorporeal blood circuit 1000 can be calculated from the constant blood flow Q_B (ml/min) and the time difference between the first point of time t1 (sec) and the second point of time t2 (sec) as follows:

V_Set=(t2t1)Q_B/60 (in ml)(1)

Due to the known relation:

V_Set=V_Dial+V_Schlauch(2)

with V_Set being the volume of the entire blood tube set, the Volume V_Dial of the Dialyzer can be measured, if the volume of the tube V_Schlauch is known, by way of:

V_Dial=V_SetV_Schlauch.(3)

[0137] Components which are shown in the extracorporeal blood circuit of FIG. 1 may be part of the extracorporeal blood circuit of FIG. 3, and vice versa.