METHOD FOR AUTOMATED PRIMING OF AN EXTRACORPOREAL BLOOD CONDUIT SYSTEM, AND A DEVICE FOR SAME

Abstract

A method and apparatus for priming an extracorporeal blood system. The extracorporeal blood system includes an arterial blood line, a venous blood line, a pump segment for interaction with a peristaltic blood pump of the apparatus and a blood treatment unit. A port of the venous blood line is connected to a venous blood port of the blood treatment unit. A port of the arterial blood line is connected to an arterial blood port of the blood treatment unit. The extracorporeal blood system is connected to a reservoir containing priming liquid. The non-occluded extracorporeal blood system is subsequently filled with priming liquid and, after filling with priming liquid, the pump segment is automatically occluded by a blood pump.

Claims

1. A method of priming an extracorporeal blood system, the extracorporeal blood system comprising an arterial blood line, a venous blood line, a pump segment for interaction with a blood pump of the apparatus, and a blood treatment unit, the method comprising the steps of: connecting a port of the venous blood line to a venous blood port of the blood treatment unit; connecting a port of the arterial blood line to an arterial blood port of the blood treatment unit; connecting the extracorporeal blood system to a reservoir containing priming liquid; and filling the extracorporeal blood system with priming liquid, the pump segment being inserted into or positioned relative to the blood pump prior to filling with priming liquid so that during filling of priming liquid into the extracorporeal blood system, the pump segment is not occluded by the blood pump and, after complete filling of the extracorporeal blood system with priming liquid, the pump segment is automatically placed and occluded in the delivery path of the blood pump by activating the blood pump.

2. The method according to claim 1, wherein the extracorporeal blood system is connected to the reservoir containing priming liquid, as a patient-side port of the venous blood line or a patient-side port of the arterial blood line or a filling line being fluid-connected thereto is connected to the reservoir containing priming liquid.

3. The method according to claim 2, wherein the patient-side port of the venous blood line is connected to the reservoir containing priming liquid and subsequently the extracorporeal blood system is filled from the arterial side to the venous side with priming liquid, wherein the reservoir is a substitute port of the apparatus or an external container containing priming liquid, or in that the patient-side port of the arterial blood line is connected to the reservoir containing priming liquid and subsequently the extracorporeal blood system is filled from the venous side to the arterial side with priming liquid, wherein the reservoir is the substitute port of the apparatus or the external container containing priming liquid.

4. The method according to claim 1, wherein, prior to filling with priming liquid, a patient-side port of the venous blood line or a patient-side port of the arterial blood line is connected to a process liquid port of the apparatus for extracorporeal blood treatment or to a separate process liquid reservoir.

5. The method according to claim 1, wherein during priming after filling with priming liquid the blood pump is operated in a delivery direction which is opposed to the delivery direction during blood treatment.

6. The method according to claim 1, wherein, prior to filling with priming liquid, the blood system is connected to the apparatus for extracorporeal blood treatment in a manner intended for treatment, with the exception that the pump segment is not occluded.

7. The method according to claim 1, wherein, prior to filling of the extracorporeal blood system with priming liquid, a sensor test run is carried out, especially by closing the arterial blood line and/or the venous blood line and pressure is increased in the extracorporeal blood system.

8. The method according to claim 1, wherein the priming liquid is filled into the extracorporeal blood system by excess pressure on a substitute port of the apparatus or hydrostatic pressure.

9. An apparatus for extracorporeal blood treatment comprising: a blood pump for delivering liquid in a pump segment of an extracorporeal blood system, the extracorporeal blood system comprising an arterial blood line, a venous blood line, the pump segment and a blood treatment unit, wherein the blood pump has a partially circular guiding surface and a rotor being rotationally driven about a substantially horizontal axis of rotation and interacting with the guiding surface such that in the pump segment disposed between the guiding surface and the rotor a cross-sectional constriction is formed, wherein the guiding surface extends from an area beneath the rotor partially around the rotor up to an area above the rotor and is open towards a side and the apparatus and/or the blood pump include(s) at least one retaining device for retaining the pump segment in a non-occluding manner in a way which enables the pump segment to be automatically threaded into the blood pump.

10. The apparatus according to claim 9, wherein the rotor is driven and/or controlled for occluding the extracorporeal blood system in such a way that it is positioned relative to the guiding surface in a direction transversely to its axis of rotation and is held in said position and/or includes pressing elements which can be positioned relative to the axis of rotation of the rotor in the radial direction.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0044] Hereinafter, the invention shall be described in detail by way of exemplary non-limiting embodiments shown in the enclosed Figures, wherein:

[0045] FIG. 1 shows a schematic circuit diagram of an apparatus for extracorporeal blood treatment during blood treatment,

[0046] FIG. 2 shows a schematic circuit diagram of the apparatus for extracorporeal blood treatment of FIG. 1 during a first sequence of preparing the blood treatment (priming),

[0047] FIG. 3 shows a schematic circuit diagram of the apparatus for extracorporeal blood treatment of FIG. 1 during a second sequence of preparing the blood treatment (priming),

[0048] FIG. 4 shows a detailed view of a blood pump of the apparatus during preparation, and

[0049] FIG. 5 shows a detailed view of the blood pump of the apparatus during blood treatment.

DETAILED DESCRIPTION

[0050] FIG. 1 illustrates in a schematic circuit diagram the liquid system 1 of an apparatus for extracorporeal blood treatment, here in the form of a dialysis apparatus, during treatment such as hemodialysis, hemofiltration or hemodiafiltration. The liquid system comprises an extracorporeal blood system 2, also referred to as extracorporeal blood circuit, and a dialysis fluid circuit 3.

[0051] The extracorporeal blood system 2 substantially consists of an arterial blood line 4, in this case in the form of an arterial tube line 4, a venous blood line 5, in this case in the form of a venous tube line 5, and a blood treatment unit 6 in the form of a filter 6 or a dialyzer 6. During blood treatment, the extracorporeal blood system 2 connects a patient 7 indicated in FIG. 1 to the dialysis apparatus.

[0052] The arterial blood line 4 includes a patient-side port 8 in the form of an arterial cannula 8 as well as a filter-side port 9 in the form of a Luer connector 9. Moreover, the arterial blood line 4 comprises a pump segment 10 for interaction with a blood pump 11 of the blood treatment apparatus. The venous blood line 5 comprises a patient-side port 12 in the form of a venous cannula 12 as well as a filter-side port 13 in the form of a Luer connector 13. By way of flow direction arrows it is indicated in FIG. 1 that blood is taken from the patient 7 during treatment by means of the arterial cannula 8 and is delivered by means of the blood pump 11 through the arterial blood line 4 via an arterial air trap 14 to the dialyzer 6. In the latter, the actual treatment, purification in this case, of the blood takes place. From the dialyzer 6 the blood flows through the venous blood line 5 and a venous air trap 16 to the venous cannula 12 back into the patient 7. The dialyzer 6 is also integrated in the dialysis fluid circuit 3 and dialysis fluid which is delivered by means of a dialysis fluid pump 15 flows through the dialyzer in a counterflow. The dialysis fluid circuit 3 moreover includes a balancing unit 17 and an ultra-filtration pump 18.

[0053] The blood pump 11 is in the form of a peristaltic pump 11. It includes a pump housing 19 having a partially circular guiding surface 20, a rotor 21 including pressing elements 30, e.g. in the form of pressing rolls 30, which is rotatably driven about a substantially horizontal rotor axis or axis of rotation 29 within the partially circular guiding surface 20 as well as a retaining contour 22 for retaining the arterial blood line 4 in a non-closing/non-occluding manner. As is evident from the Figures, the pump segment 10 is part of the arterial blood line 4, viz. the part located between the guiding surface 20 and the rotor 21 in the blood pump 11. Within the scope of the invention, the pump segment 10 may further be configured as a separate elastically deformable fluid line which is connected to the arterial blood line 4 on both sides. During blood treatment, the pump segment 10 is deformed and squeezed, i.e. occluded, by the action of the rotor 21 between the latter and the guiding surface 20 of the pump housing 19 in such a way that fluid is conveyed from the low-pressure side of the arterial blood line 4 to the high-pressure side thereof (indicated by flow direction arrows in FIG. 1).

[0054] The apparatus for extracorporeal blood treatment shown in FIGS. 1, 2 and 3 moreover may comprise further measuring units, pumps, bubble traps etc. which are not shown. For monitoring therapeutic operations, it includes especially pressure transducers or pressure sensors 23, 24, 25. In detail, these are an inlet pressure sensor 23 sensing the pressure on the high-pressure side of the blood pump 11, an arterial pressure sensor 24 between the arterial cannula 8 and the blood pump 11 as well as a venous pressure sensor 25 in the area of the venous air trap 16.

[0055] FIG. 2 illustrates the liquid system 1 shown during treatment in FIG. 1 during a first sequence of priming/the preparation for the treatment as part of a method according to the invention. FIG. 3 illustrates the liquid system 1 during a second sequence of priming/the preparation for treatment following the first sequence as part of a method according to the invention. Other than during treatment, during the preparation the arterial patient-side port 8 and the venous patient-side port 12 are not connected to the bloodstream of a patient. Rather, the arterial patient-side port 8 is connected to a liquid reservoir 27 containing priming liquid 26 and the venous patient-side port 12 is connected to a process liquid reservoir 28. The liquid reservoir 27 may especially be an internal reservoir 27 of the apparatus for extracorporeal blood treatment having a substitute port or an external reservoir 27 containing priming liquid. The process liquid reservoir 28 may especially be an internal process liquid reservoir 28 having a process liquid port (waste port) of the apparatus for extracorporeal blood treatment or a separate process liquid reservoir 28, especially a waste container or waste bag.

[0056] It is a special feature of the method according to the invention shown in detail in FIG. 2 that during preparation/priming the pump segments 10 is not and will not be occluded by the blood pump 11. In the method according to the invention, initially the extracorporeal blood system 2 is completely set up. This means that initially the filter-side port 13 of the venous blood line 5 as well as the filter-side port 9 of the arterial blood line 4 are connected to the blood treatment unit (filter, dialyzer). After that, the patient-side arterial port 8 is connected to the process liquid reservoir 28 and the patient-side venous port 12 is connected to the liquid reservoir 27. Alternatively, the patient-side ports 8 and, resp., 12 can be connected to the substitute port and, resp., the waste port of the machine for automatic priming. In the present case, the liquid reservoir 27 is a simple container 27 containing saline solution as priming liquid 26. The blood system 2 is not yet filled with liquid.

[0057] The pump segment 10 not filled with liquid is inserted into the retaining contour 22 of the blood pump 11 and is not occluded by the pump. As an alternative, the pump segment 10 may be suspended over the rotor 21 of the blood pump 11 such that it is held at the rotor 21 but is not squeezed or occluded between the rotor 21 and the guiding surface 20. According to another alternative, it may simply be suspended over a hook or an IV pole not shown in the Figures. What is essential is that no occlusion takes place, viz. that the cross-section of the blood line is not closed. In this way, the pump segment 10 is continuously open during the filling operation of the blood system 2 with priming liquid 26.

[0058] In the following, the blood system 2 is completely filled with priming liquid 26. Filling is carried out, for example, by means of excess pressure from the substitute port (preferably by means of a substitute pump or any other pump of the apparatus) or by means of hydrostatic pressure from the saline solution reservoir 27. Only when the blood system 2 is completely filled, i.e. the arterial blood line 4, the venous blood line 5, the pump segment 10 and the treatment unit 6, the pump segment 10 optionally can be automatically threaded. This may be simply carried out by activating the blood pump 10, which allows the rotor 21 to automatically seize the line retained in the retaining contour 22 and to place and occlude the same in the manner intended for delivering liquid between itself and the guiding surface. In the further course of priming, the priming liquid 26 is delivered through the blood system 2 from the venous side to the arterial side e.g. by a reverse rotation of the blood pump 10; this direction of rotation is marked by arrow A in FIG. 3.

[0059] In the fluid-connection of the blood system 2 to the liquid reservoir 27 and to the process liquid reservoir 28 and, resp., the apparatus for extracorporeal blood treatment as illustrated in FIGS. 2 and 3, in the first sequence of preparation, especially when filling the blood system with priming liquid, priming takes place from the venous side to the arterial side, as is indicated by the flow direction arrows included in FIGS. 2 and 3. This is opposite to the direction typically used for priming. By priming from the venous side to the arterial side air can be completely displaced from the venous air trap 16 as the latter is filled from the bottom. This is of particular advantage for so-called “air-free blood lines”. It is pointed at the fact that, within the scope of the method according to the invention, in the second sequence of preparation, especially after the blood system has been filled with priming liquid, the priming liquid can be delivered in both flow directions through the system, even if in FIG. 3 flow arrows point in one direction only.

[0060] A method step which is not mandatory consists in carrying out a test of the sensors 23, 24, 25 prior to actually filling the blood system with priming liquid. To this end, the arterial blood line 4 and the venous blood line 5 can be closed by means of arterial and venous stop clamps not shown in the Figures. By means of a pump integrated in the machine, for example, then the air pressure in the blood system can be increased by inflow via a pressure port. Since all sensors 23, 24, 25 are hydraulically interconnected via the non-occluded lines of the extracorporeal blood system 2, they can be tested relative to each other. A possible offset due to a hydrostatic difference in pressure resulting from the height difference has to be taken into account.

[0061] FIG. 4 illustrates a detailed view of a blood pump 10 of the apparatus during preparation. The pump segment 10 is inserted in the retaining contour 22 but is not yet occluded between the rotor 21 and the guiding surface 20. In order to be capable of displacing air contained in the blood system in a preferably residue-free and complete manner, the arterial blood line 4 and the pump segment 10 in this case are advantageously filled from the bottom to the top, which is why the blood pump 11 is arranged and oriented at the apparatus so that it is opened towards the side (cf. also FIGS. 1, 2 and 3).

[0062] FIG. 5 illustrates a detailed view of the blood pump 11 of the apparatus during blood treatment after the first sequence of priming, viz. after complete filling of the blood system with priming liquid. The pump rotor 21 has been rotated out of the position as shown in FIG. 4 and the pump segment 10 has been automatically caught by the rotor 21 and threaded between the latter and the guiding surface 20. At least one roll of the rotor 21 then is engaged with the pump segment 11 and occludes the same. As soon as the pump segment 10 has been threaded, the blood pump 11 can be used for delivery. The priming liquid contained in the blood system can be circulated within the latter until a patient is connected and treatment is started.