Method for removing fluid from a blood filter at the end of a blood treatment session and treatment apparatus for executing the method

Abstract

The present invention relates to a method for removing fluid from a blood filter which is used for the blood treatment of a patient and/or for removing blood from an extracorporeal blood circuit at the end of a blood treatment session. It further relates to a medical treatment apparatus with a control and/or regulating device which executes the method according to the present invention. It further relates to a digital storage medium, a computer program product as well as a computer program for executing the method according to the present invention.

Claims

1. A method for displacing dialysate fluid from a dialysate chamber of a blood filter used for a blood treatment of a patient, the method comprising the steps of: after the blood treatment of the patient and prior to emptying a blood chamber of the blood filter such that the blood chamber contains full of blood, closing or sealing the blood chamber against atmosphere wherein the blood filter includes a membrane arranged between the blood chamber and the dialysate chamber, wherein the blood chamber is connected with an arterial blood line leading to the blood chamber and with a venous blood line leading away from the blood chamber, and wherein the dialysate chamber is connected with a dialysate inlet line leading to the dialysate chamber and with a dialysate outlet line leading away from the dialysate chamber; and while the blood chamber remains closed or sealed against the atmosphere and prevented from emptying, displacing the dialysate fluid from the dialysate chamber by actively or passively introducing air or a liquid into the dialysate inlet line such that the air or liquid enters the dialysate chamber, wherein no fluid from the dialysate chamber transfers across the membrane during the displacing.

2. The method according to claim 1, further comprising the step of: regulating or controlling an introduction of the air into the dialysate inlet line while considering pressure measurements from at least one pressure sensor provided in or on the dialysate inlet line or the dialysate outlet line.

3. The method according to claim 1, wherein the closing or sealing the blood chamber comprises closing at least one of an arterial tube clamp along the arterial blood line and a venous tube clamp along the venous blood line.

4. The method according to claim 1, further comprising the step of: closing a valve in a blood cassette to further seal the venous blood line from the atmosphere.

5. The method according to claim 1, further comprising the step of: setting or prompting a pressure present in the blood chamber to a pressure value which is above a dialysate pressure present in the dialysate chamber.

6. The method according to claim 1, further comprising: after the displacing of the dialysate fluid from the dialysate chamber, emptying the blood chamber.

7. The method according to claim 1, wherein emptying the dialysate chamber is finished and then emptying the blood chamber is started.

8. The method according to claim 1, wherein after the displacing of the dialysate fluid from the dialysate chamber, said blood is removed at least one of: (a) from the blood chamber of the blood filter and (b) from an extracorporeal blood circuit which is connected with the blood filter, wherein said blood is removed using a blood pump located along the extracorporeal blood circuit, and a second conveying device configured to at least one of: (i) introduce a substituate liquid into the extracorporeal blood circuit and (ii) convey a line content within line interior portions of the extracorporeal blood circuit.

9. The method according to claim 8, further comprising the step of: recording a qualitative change of the line interior portions of the extracorporeal blood circuit using a detection device arranged along a section of the extracorporeal blood circuit.

10. The method according to claim 1, further comprising the step of: disconnecting the arterial blood line and the venous blood line from the patient's vascular system.

11. The method according to claim 8, further comprising conveying, by the blood pump, a defined volume of air into line interior portions of the extracorporeal blood circuit by operating the blood pump.

12. The method according to claim 8, wherein an air-blood content in the line interior portions of the extracorporeal blood circuit is conveyed until an air-blood boundary reaches an addition point of the extracorporeal blood circuit for the substituate liquid into the line interior portions of the extracorporeal blood circuit, and wherein substituate liquid is introduced into the line interior portions of the extracorporeal blood circuit via the addition point when the addition point is reached by the air-blood boundary.

13. The method according to claim 12, wherein a predetermined amount of the substituate liquid is introduced into the line interior portions of the extracorporeal blood circuit by operating the second conveying device.

14. The method according to claim 12, wherein the substituate liquid introduced is conveyed away from a disconnected end of the extracorporeal blood circuit by operating the second conveying device until a detection device detects the substituate liquid in the line interior portions of the extracorporeal blood circuit.

15. The method according to claim 12, wherein air-substituate liquid-blood content is conveyed along the line interior portions of the extracorporeal blood circuit by at least one of operating the blood pump and operating the second conveying device.

16. The method according to claim 12, wherein the second conveying device introduces the substituate liquid into the line interior portions of the extracorporeal blood circuit at a first point of time and the second conveying device introduces air into the line interior portions of the extracorporeal blood circuit at a second point of time which differs from the first point of time.

17. The method according to claim 9, wherein the detection device is arranged with a predetermined distance to a second access device, and wherein the method further comprises the step of: conveying a content of the line interior portions of the extracorporeal blood circuit across the predetermined distance to the second access device after the air is identified by the detection device.

18. The method according to claim 17, wherein the blood contained in the line interior portions of the extracorporeal blood circuit is introduced into the patient's vascular system via the second access device.

19. The method according to claim 1, wherein no fluid is transferred across the membrane during the displacing.

20. The method according to claim 1, further comprising: establishing a connection outside of the blood chamber between the arterial blood line and the venous blood line.

21. A system for displacing dialysate fluid from a dialysate chamber of a blood filter used for a blood treatment of a patient, said system comprising: a control or regulating device configured to control or regulate the execution of a method comprising: after the blood treatment of the patient and prior to emptying a blood chamber of the blood filter such that the blood chamber contains full of blood, closing or sealing the blood chamber against atmosphere, wherein the blood filter includes a membrane arranged between the blood chamber and the dialysate chamber, wherein the blood chamber is connected with an arterial blood line leading to the blood chamber and with a venous blood line leading away from the blood chamber, and wherein the dialysate chamber is connected with a dialysate inlet line leading to the dialysate chamber and with a dialysate outlet line leading away from the dialysate chamber; and while the blood chamber remains closed or sealed against the atmosphere and prevented from emptying, displacing the dialysate fluid from the dialysate chamber by actively or passively introducing air or a liquid into the dialysate inlet line such that the air or liquid enters the dialysate chamber, wherein no fluid from the dialysate chamber transfers across the membrane during the displacing.

22. The system according to claim 21, further comprising: a blood pump arranged along an extracorporeal blood circuit that is connected with the blood filter, the blood pump operable for conveying blood within line interior portions of the extracorporeal blood circuit; and a device for introducing air into the dialysate inlet line.

23. The system according to claim 22, further comprising: a conveying device for at least one of introducing a substituate liquid into the line interior portions of the extracorporeal blood circuit and conveying a line content within the line interior portions of the extracorporeal blood circuit.

24. The system according to claim 22, further comprising: a detection device arranged in or at a section of the extracorporeal blood circuit for detecting a change of a property of the line content within the line interior portions of the extracorporeal blood circuit.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Hereafter, the method according to the present invention is exemplarily described by preferred embodiments with reference to the appended drawing. In the drawing, it applies that:

(2) FIG. 1 shows a schematic overview of an exemplary arrangement as a part of a blood cassette for executing the method according to the present invention.

DETAILED DESCRIPTION

(3) FIG. 1 shows an extracorporeal blood circuit 1 which is connected by utilization of a double-needle access with the vascular system of the patient which is not illustrated here. The blood circuit 1 is present in sections hereof in or on a blood cassette 2. It is connected with a treatment apparatus 4.

(4) The blood circuit 1 comprises an arterial patient tube clamp 6 and an arterial connection needle 5 (as an example for an access device) of an arterial section or an arterial blood line 9. The blood circuit 1 further comprises a venous patient tube clamp 7 and a venous connection needle 27 (as an example for a further or second access device) of a venous section or a venous blood line 23.

(5) A blood pump 11 is provided in the arterial section 9, a substituate pump 17 is connected with a substituate line. The substituate line can be connected with a source of substituate by utilization of an automatic substituate port 18. By utilizing the substituate pump 17, substituate may be introduced via predilution or via postdilution and via associated lines 13 or 14 into line section of the blood circuit 1.

(6) A blood filter 19 is provided in the blood circuit 1. It comprises a blood chamber 19a which is connected with the arterial section 9 and with the venous section 23. A dialysate chamber 19b is connected with a dialysate inlet line 31a which leads to the dialysate chamber 19b and with a dialysate outlet line 31b which leads away from the dialysate chamber 19b.

(7) The dialysate inlet line 31a comprises a valve V24 by which the flow within the dialysate inlet line 31a can be stopped. The dialysate outlet line 31b comprises a valve V25 by which the flow within the dialysate outlet line 31b may be stopped.

(8) The dialysate inlet line 31a is further connected with a source 26 of compressed air via another valve of the apparatus.

(9) For executing the method according to the present invention with the aim of at first emptying the dialysate chamber 19b of the blood filter 19 at the end of the treatment, the dialysate inlet line 31a and the dialysate outlet line 31b each remain connected with the blood filter 19. A negative pressure is applied to the dialysate outlet line 31b via the valve V25. Alternatively or additionally, air is introduced into the dialysate chamber 19b via the machine-internal valve V24. The introduced air may be compressed air from the source 26 of compressed air. The source 26 of compressed air may be a part of the treatment apparatus 4 or be separate from it.

(10) The introduced air may alternatively be atmospheric air which may enter the dialysate inlet line 31a by opening the corresponding valves or other components.

(11) The intake of air or a different gas may be controlled by utilization of one or several sensors, in particular pressure sensors. The one or more sensors may be provided at the dialysate inlet and/or dialysate outlet. In particular, they may be provided in the dialysate inlet line 31a and/or the dialysate outlet line 31b, as is exemplarily shown in FIG. 1 with a pressure sensor 37.

(12) In order to prevent a displacement of dialysate from the dialysate chamber 19b via or across the membrane into the blood chamber 19a, as is intended in certain embodiments according to the present invention, it may be of advantage to keep the blood cassette 2 or the extracorporeal blood circuit 1 closed or to close it against the atmosphere on the blood side. This may be done for example by closing the arterial and venous patient tube clamps 6 and 7 as well as the single-needle valve 34 when using the arrangement illustrated in FIG. 1. Alternatively, a transfer of liquid to the blood side of the membrane may be prevented by suitably choosing the operating pressures. In doing so, the fluid pressure on the blood side of the membrane may be greater or may be set to be higher than on the dialysate side. The pressure on the blood side may be measured for example by means of one or more pressure sensor(s) 33a, b which is/are provided in the extracorporeal blood circuit 1 and in particular in the arterial and/or venous section.

(13) If in addition to this the extracorporeal blood circuit 1 and/or the blood chamber 19a is to be emptied from fluid, i.e. blood, this may be carried out exemplarily as follows:

(14) The extracorporeal blood circuit 1 is being disconnected from the vascular system of the patient by removing the arterial connection needle 5 from the arm of the patient.

(15) For starting the method according to the present invention in a first embodiment, at first the venous patient tube clamp 7 is opened. Subsequently, the blood pump 11 is started and that way air is drawn into the arterial section 9 of the extracorporeal blood circuit 1. The blood pump 11 is exemplarily embodied as a roller pump and introduces ane.g., predeterminedvolume of air into the extracorporeal blood circuit 1 via the disconnected end. After that, the air-blood content is conveyed along line interior portions of the extracorporeal blood circuit 1 in the direction towards the venous connection needle 27 by operating the blood pump 11.

(16) In this embodiment, the predetermined volume of air is defined such that the air-blood limit in line interior portions of the extracorporeal blood circuit 1 comes to a standstillas exactly as possiblein front of the addition point 13 for substituate liquid. In order to increase the accuracy of stopping the air-blood limit in front of or at the addition point 13 for substituate liquid, an arterial air-blood detector 15 as an example of a detection device may be positioned at a suitable location in the arterial section 9 of the extracorporeal blood circuit 1 between the addition point 13 for substituate liquid and the arterial connection needle 5.

(17) When or if the air-blood limit reaches the addition point 13 for substituate liquid, the blood pump 11 is stopped. The second conveying device, the substituate pump 17 which is here exemplarily embodied as a roller pump, introduces apreferablypre-set volume of substituate liquid into line interior portions of the extracorporeal blood circuit 1 via the addition point 13 for substituate liquid. The substituate pump 17 may subsequently be stopped.

(18) Alternatively, the substituate liquid may also be introduced by operating the blood pump 11. For this, the arterial patient tube clamp 6 is closed and the substituate liquid is introduced into the extracorporeal blood circuit 1 via a supply line 8 from a storage container for the substituate liquid.

(19) The achieved air-substituate liquid-blood content is conveyed along line interior portions of the extracorporeal blood circuit 1 by once again operating the blood pump 11 and pressed or conveyed through the blood filter 19, the venous air separation chamber 21 and a venous section 23 of the extracorporeal blood circuit 1 in order to remove the blood from the extracorporeal blood circuit 1 in the direction towards the venous connection needle 27. In doing so, air can in turn be introduced via the blood pump 11 and/or the substituate pump 17.

(20) In the venous section 23 of the extracorporeal blood circuit 1, a venous air-substituate liquid-blood detector 25 is arranged as a further example of a detection device which detects the occurrence of substituate liquid at a predetermined position of line interior portions of the extracorporeal blood circuit 1. The blood pump 11 continues conveying the air-substituate liquid-blood content for so long until the blood in the venous section 23 of the extracorporeal blood circuit 1 is removed from it and returned to the vascular system of the patient via the venous connection needle 27, and/or until air is detected in line interior portions of the extracorporeal blood circuit at the venous air-substituate liquid-blood detector 25. The conveying effort of all pumps is being stopped. An optical and/or acoustical signal can be output.

(21) Controlling or regulating the treatment apparatus 4 may take place by utilization of a control or regulating device 29.

(22) A second embodiment of the present invention basically corresponds to the first embodiment described above, except that the air-substituate liquid-blood content in line interior portions of the extracorporeal blood circuit 1 after the addition of the substituate liquid is not conveyed along line interior portions of the extracorporeal blood circuit 1 by operating the blood pump 11 but by operating the substituate pump 17.

(23) The present invention is not limited to the embodiments as described above, they only serve illustration. Furthermore, the present invention is not limited to emptying the content or parts hereof while a connection with the vascular system still exists.