Pressure Measuring Line and Method for Monitoring the Same with Suitable Devices and Apparatuses

Abstract

The present disclosure relates to a pressure measuring line, with a connector to connect the pressure measuring line to a blood treatment apparatus, and to a membrane. In some embodiments, the pressure measuring line comprises at least two consecutive lumen sections, namely the first lumen section and the second lumen section. The first lumen section comprises a first lumen geometry and the second lumen section comprises a second lumen geometry, whereby the first lumen geometry and the second lumen geometry differ from each other in at least their diameters. Further, a monitoring method and devices are described.

Claims

1. A pressure measuring line with a membrane and a connector to connect the pressure measuring line to a blood treatment apparatus, wherein the pressure measuring line additionally comprises at least two consecutive lumen sections, namely a first lumen section and a second lumen section, wherein the first lumen section comprises a first lumen geometry and the second lumen section comprises a second lumen geometry, whereby the first lumen geometry and the second lumen geometry differ from each other in at least their diameters.

2. The pressure measuring line according to claim 1, having several lumen sections each having the first lumen geometry and/or several lumen sections each having the second lumen geometry.

3. The pressure measuring line according to claim 2, whereby the several lumen sections each having the first lumen geometry are separate from each other.

4. The pressure measuring line according to claim 3, whereby the several lumen sections each having the second lumen geometry are separate from each other.

5. The pressure measuring line according to claim 4, wherein the several lumen sections each having the first lumen geometry alternate with the several lumen sections each having the second lumen geometry.

6. The pressure measuring line according to claim 1: also comprising a further connector to connect the pressure measuring line to a blood chamber.

7. A blood chamber, comprising or connected to the pressure measuring line according to claim 1.

8. An extracorporeal blood tubing set, comprising or connected to the blood chamber according to claim 7 and/or the pressure measuring line according to claim 1.

9. The extracorporeal blood tubing set according to claim 8, wherein the pressure measuring line is connected to the blood chamber.

10. A detection device, programmed and/or configured to perform or initiate a method for monitoring the pressure measuring line according to claim 1, wherein the pressure measuring line is a portion of an extracorporeal blood tubing set, wherein the pressure measuring line is connected to a blood treatment apparatus, wherein the blood treatment apparatus comprises a pressure sensor, which is positioned to measure a pressure (P) inside the pressure measuring line; wherein the method comprises: measuring, using the pressure sensor, the pressure (P) in the pressure measuring line or its change over time, and determining a deviation variable (δ2) of the pressure (P) or of its change; and evaluating the deviation variable (δ2) or the change in the deviation variable (δ2) over time, in each case each via a comparison of the determined deviation variable (δ2), or its change with previously measured and/or stored values, threshold values, ranges or courses used therefor.

11. The detection device according to claim 10, wherein the evaluation is or encompasses reaching a conclusion about the pressure measuring line.

12. The detection device according to claim 11, wherein the conclusion reached is, or indicates, that there is a risk of the membrane and/or the pressure sensor getting wet, a predetermined height (h) of the liquid level in the pressure measuring line is reached, and/or that the liquid level in the pressure measuring line is rising.

13. The detection device according to claim 12, wherein in response to reaching the conclusion that there is a risk of the membrane getting wet an error message or an alarm is triggered.

14. The detection device according to claim 10, wherein the method further comprises: interrupting or halting of a blood treatment via the blood treatment apparatus; or: taking measures, using the blood treatment apparatus, to lower the liquid levels in the blood chamber; in each case when the conclusion reached about the connection is or indicates that there is a risk of getting wet and/or the predetermined height (h) of the level has been exceeded.

15. The detection device according to claim 10, wherein the blood treatment apparatus is an apparatus for apheresis or dialysis, in particular for hemodialysis, hemofiltration, hemodiafiltration.

16. The detection device according to claim 10, further comprising at least one display device, or being connected to one, and wherein the display device is configured to display a result of executing the method.

17. A blood treatment apparatus comprising or connected to at least one extracorporeal blood tubing set according to claim 8 and/or to a detection device according to claim 10.

18. The blood treatment apparatus according to claim 17, embodied as an apparatus for apheresis, hemodialysis, hemofiltration, or hemodiafiltration.

19. A method for monitoring a pressure measuring line of an extracorporeal blood tubing set, the method comprising: providing a blood treatment apparatus with a connection point, which is connected to a pressure measuring line according to claim 1, and with a pressure sensor positioned to measure the pressure (P) in the pressure measuring line; measuring, using the pressure sensor, the pressure (P) in the pressure measuring line or its change over time, and determining a deviation variable (δ2) of the pressure (P) or of its change; and evaluating the deviation variable (δ2) or a change in the deviation variable (δ2) over time, in each case via a comparison of the determined deviation variable (δ2) or of its change, with previously measured or stored values, threshold values, ranges or courses.

20. The method according to claim 19, wherein the evaluation is or encompasses reaching a conclusion about the pressure measuring line.

21. The method according to claim 20, wherein the conclusion reached is or indicates that there is a risk of the membrane and/or the pressure sensor getting wet, a predetermined height (h) of the liquid level in the pressure measuring line is reached and/or that the liquid level in the pressure measuring line is rising.

22. The method according to claim 21, wherein in reaching the conclusion that there is a risk of the getting wet an error message or an alarm is triggered.

23. The method according to claim 10, further comprising: interrupting or halting of a blood treatment via the provided blood treatment apparatus; or: taking measures, using the blood treatment apparatus, to lower the liquid level in a blood chamber connected to the pressure measuring line; in each case when the reaching of a conclusion about the connection is or indicates that there is a risk of it getting wet and/or that the predetermined height (h) of the level has been exceeded.

24. The method according to claim 19, wherein the blood treatment apparatus is an apparatus for apheresis, hemodialysis, hemofiltration, or hemodiafiltration.

25. A digital storage medium in the form of a floppy disk, CD or DVD or in the form of a USB-stick or EPROM, with electronically readable control signs, configured to interact with a programmable computer system, so that it initiates the machine-induced steps of a method according to the present invention according to claim 19.

26. A computer program product, as a signal wave or with a program code stored on a machine-readable medium, to initiate the machine-induced steps of the method according to the present invention, according to claim 19, when the computer program product runs on a computer.

27. A computer program with a program code to initiate the machine-induced steps of a method according to the present invention according to claim 19, when the computer program runs on a computer.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0093] The present disclosure is, in the following, exemplarily explained with regard to the accompanying drawings in which identical reference numerals refer to the same or similar components. The following applies in the partly highly simplified figures:

[0094] FIG. 1 shows a simplified schematic graph of a blood treatment apparatus according to the present disclosure and a first pressure measuring line of a blood tubing set according to the present disclosure in a first embodiment;

[0095] FIG. 2 shows in a simplified schematic a pressure measuring line according to the present disclosure in a second embodiment;

[0096] FIG. 3a, 3b each show a diagram, in which is shown pressure measured by the pressure sensor in FIG. 1 according to the present disclosure, over time;

[0097] FIG. 4 shows two courses of the deviation variable of the venous pressure in the bubble trap, measured by the pressure sensor in FIG. 1. One with a predominantly air-filled bubble trap and one with a predominantly liquid filled bubble trap, each over time t in seconds [s] at a set blood flow of 100 ml/min;

[0098] FIG. 5 shows in a simplified diagram that the deviation variable is dependent on the air volume in the pressure measuring line and in the bubble trap;

[0099] FIG. 6 shows in a simplified diagram that the air volume is dependent on the liquid level in the pressure measuring line and in the bubble trap; and

[0100] FIG. 7 shows an non continuous increase in the deviation variable in depending on the liquid level owing to the geometry of the pressure measuring line.

DETAILED DESCRIPTION

[0101] FIG. 1 shows in a very simplified schematic, sections of a blood treatment apparatus 1000 according to the present disclosure as well as sections of a blood tubing set 100 according to the present disclosure.

[0102] The inventive concepts of the present disclosure are explained herein, and in particular in the following, with reference to apparatuses according to the present disclosure, which are located on the venous side of the blood tubing set. The disclosure is not limited to its use only on the venous side of a blood tubing set.

[0103] The extracorporeal blood tubing set 100, which optionally, may extend in sections outside and inside of a blood cassette—not shown—, comprises a venous patient line 101 and, optionally, a venous blood chamber 103. During use a through-flow of blood in the patient line 101 occurs typically towards the patient, in the direction of the arrows as indicated.

[0104] A pressure measuring line 105 according to the present disclosure is connected to the blood tubing set 100 (or a part thereof). In FIG. 1 this pressure measuring line 105, purely illustratively, exits from the venous blood chamber 103, here embodied as a bubble trap. The pressure measuring line 105 may be the return pressure measuring line. It may be an “open line”.

[0105] The pressure measuring line 105 optionally comprises a connector 107, which is provided and embodied accordingly, to connect the pressure measuring line 105 to, for example, a compressed air outlet 1001 of the blood treatment apparatus 1000. The connector 107 and the compressed air outlet 1001 are, purely optionally, female or male halves of a Luer-lock-connector with a female or male sealing cone or halves of a corresponding Luer-lock-connector with or without additional safety thread.

[0106] The compressed air outlet 1001 may be in or on, an outside wall of the blood treatment apparatus 1000, for example, in its housing wall.

[0107] The connector 107 of the pressure measuring line 105, or another section of the pressure measuring line 105, which when the pressure measuring line 105 is in use, lies in an area of the pressure measuring line 105 through which air flows or through which air can flow, comprises an air-permeable membrane 109. The air-permeable membrane 109 is embodied, purely as an example, as a hydrophobic membrane or as a hydrophobic filter. The air-permeable membrane 109 is also known to the person skilled in the art by the name “transducer protector” or when abbreviated as “TP”.

[0108] The blood treatment apparatus 1000 comprises a compressor 1003 as an example of a compressed air device or a compressed air source.

[0109] Compressor 1003 and compressed air outlet 1001 are, for example, connected in fluid communication via a compressed air line 1005. Optionally, the compressor 1003 may comprise additional valves for a use other than that described herein.

[0110] A pressure sensor 1007 and, purely illustratively, an optional switch valve 1009 (alternatively or additionally a choke, a switch, a lock and/or similar) are provided in or on the compressed air line 1005.

[0111] As can be seen in FIG. 1, the pressure sensor 1007 is preferably integrated into the compressed air line 1005 or is in suitable fluid communication to it, so that it can measure the pressure P in the compressed air line 1005 caused by the operation of the compressor 1003, if the switch valve 1009 (if provided) is switched accordingly and if the compressor 1003 is active, i.e. switched on. The pressure sensor 1007 may be the return pressure sensor.

[0112] Purely as an example, the compressed air line 1005 runs through an optionally provided protective filter 1011, which in turn comprises a, preferably hydrophobic, air-permeable membrane 1013 positioned in the running flow.

[0113] The blood treatment apparatus 1000 comprises a detection device 1300. As indicated by dashes, this is, exemplarily, connected in signal communication to the compressor 1003, the pressure sensor 1007 and/or the switch valve 1009.

[0114] As indicated by dashed-dotted lines, at the least the compressed air outlet 1001 and pressure sensor 1007 may be part of the independent pressure measuring unit 1500, which is connected to the blood treatment apparatus 1000, optionally, the switch valve 1009 and the protective filter 1011, when provided, may also be part of the above mentioned apparatus.

[0115] As can be seen in FIG. 1, the pressure measuring line 105 comprises at least one first lumen section 105a and directly adjacent to this a second lumen section 105b.

[0116] The first lumen section 105a comprises a first lumen geometry, the second lumen section 105b comprises a second lumen geometry. The first and the second lumen geometries differ from each other in at least their diameters, in that the first lumen section 105a diameter is bigger than that of the second lumen section 105b. The first lumen section 105a can therefore be referred to as an extension or compartment, the second lumen section 105b as a bottleneck.

[0117] In addition to the first lumen section 105a the pressure measuring line 105 comprises a further lumen section 105a′. This also has a bigger diameter than the directly adjacent second lumen section. The further lumen section 105a′ may have the same geometry and/or the same diameter as the first lumen section 105a. The lumen sections 105a and 105a′ will be now on referred to as “first lumen sections”.

[0118] The extracorporeal blood tubing set 100, along with the aforementioned components, optionally further comprises an arterial line section which is in fluid connection to a patient, not illustrated, and to a blood treatment apparatus, here exemplarily a blood filter or a dialyzer, also not illustrated. The blood filter comprises a dialysis liquid chamber and a blood chamber, which are separated from each other by a mostly semi-permeable membrane.

[0119] The blood treatment apparatus 1000, shown only through some of its devices and schematically represented in FIG. 1, further comprises a blood pump. During the patient's treatment it conveys blood through sections of the extracorporeal blood circuit 100 and towards the blood filter or dialyzer.

[0120] Using a pump for dialysis liquid, which may be embodied as a roller pump or as an otherwise occluding pump, fresh dialysis liquid is pumped from a source along a dialysis liquid inlet line into the dialysis liquid chamber. The dialysis liquid leaves the dialysis liquid chamber as filtrate towards a basin.

[0121] A further source with substitute may optionally be provided.

[0122] FIG. 2 shows a further embodiment of the pressure measuring line 105 according to the present disclosure. This is connected to a compressed air outlet 1001 and a bubble trap, as an example of a blood chamber 103, see FIG. 1.

[0123] The pressure measuring line 105 comprises more, e.g. three lumen sections of a first type, the first lumen sections 105a, 105a′ and 105a″. They are separated from each other by lumen sections of a second type, second lumen sections 105b, 105b′ and 105b″. Here, by way of example, lumen sections of the first type alternate with those of the second type.

[0124] FIGS. 3a and 3b each show a diagram in which the course of the pressure P, measured by the pressure sensor 1007 in FIG. 1 (e.g. in the unit mmHg), is plotted over the time t (e.g. in the unit s as seconds).

[0125] FIG. 3a shows the pressure signal, measured using the pressure sensor 1007, when the upper half of the blood chamber 103 is filled with air.

[0126] FIG. 3b shows the pressure signal, measured using the pressure sensor 1007, when the blood chamber 103 is filled to the top with liquid, in other words, no air or hardly any air is present.

[0127] It can be seen that the overshoots, indicated by circles, during pressure changes in the (semi-)air filled system in FIG. 3a are significantly lower than in FIG. 3b.

[0128] This performance is evaluated, according to the present disclosure via the deviation variable, which is here, purely as an example, a squared variable which, possibly, corresponds to the variance or simulates the variance and is therefore exemplarily indicated using δ.sup.2.

[0129] The deviation variable δ.sup.2 is here, exemplarily, the average squared deviation of the current pressure value of an averaged pressure value (e.g. 5 pressure values within 500 ms).

[0130] The deviation variable need not be a squared deviation. Therefore, the example in the present figures is certainly not to be taken as limiting.

[0131] FIG. 4 shows two courses of the deviation variable δ.sup.2 in FIG. 3 of the venous pressure in the blood chamber 103 measured using the pressure sensor 1007 in FIG. 1. One with a blood chamber 103 predominantly filled with air and one with a blood chamber 103 predominantly filled with liquid, each over time t in seconds [s] with a pre-set blood flow of 100 ml/min.

[0132] Thereby, the course V1 (dashes) of the deviation variable δ.sup.2 shows said deviation variable δ.sup.2 having values between 0 and approximately 55. This can be determined by measuring the pressure when there is, comparatively, a lot of air present in the blood chamber 103 which makes an undesirable wetting of the pressure sensor 1007 unlikely.

[0133] The course V2 (solid lines) shows a deviation variable δ.sup.2 having values between 0 and approximately 85, conversely to the deviation variable δ.sup.2 which can be determined by measuring the pressure when there is comparatively less air present in the blood chamber 103. This makes an undesirable wetting of the membrane 109 that in turn should protect the pressure sensor 1007 itself from getting wet, more likely. A reason for the different courses V1 and V2 lies in the compressible and therefore dampening properties of the air volume, whereby with an increasing liquid level and thereby decreasing air volume the dampening effect in the pressure measuring line decreases and the deviation variable of the pressure increases. If a lumen section is filled with liquid then this lumen section does not have a dampening effect, due to air and does not contribute to the overall dampening.

[0134] FIG. 5 in a simple diagram, shows that the air volume V in the pressure measuring line 105 and in the blood chamber 103 is dependent on the deviation variable δ.sup.2.

[0135] FIG. 6 in a simplified diagram, shows that the air volume V is dependent on the liquid level h in the pressure measuring line 105, assuming a constant cross section of the pressure measuring line 105.

[0136] The amount of the deviation variable δ.sup.2 therefore depends on the amount of air or the air volume V in the blood chamber 103 and in the pressure measuring line 105, as is shown in FIG. 5. The air volume V, which is present in the pressure measuring line 105, is again linear to the height h of the liquid level inside the blood chamber 103 as shown in FIG. 6.

[0137] To be able to more precisely determine up to what height h the liquid in the pressure measuring line 105 has risen to it is preferable to obtain a non-continuous increase in the deviation variable δ.sup.2 above the filling level, i.e. the height h of the liquid level, as is shown in FIG. 7. It shows the deviation variable δ.sup.2 dependent on the liquid level in the pressure measuring line 105, assuming different cross sections and therefore different volumes along the pressure measuring line 105.

[0138] For this purpose, according to the present disclosure, a hose geometry of the pressure measuring line 105 is exemplarily recommended, e.g. as is shown in FIG. 2. It is in the longitudinal section that the geometry is different from the consistently cylindrical shape of known pressure measuring lines.

[0139] If a lumen section is filled with liquid, then this lumen section does not comprise a dampening effect due to air and does not contribute to the overall dampening. Due to the different cross sections and therefore volumes per length of the pressure measuring line 105, the liquid level in the sections of the first type (first lumen geometry) rises slower than in those of the second type (second lumen geometry). This eliminates the continual dependency between volume or filling on the one hand and filling level on the other. Therefore, beneficial thresholds can be set for the deviation variable δ.sup.2 on which can be read, to which point or to which section (first type or second type) the liquid has already risen to. Appropriate measures can be initiated based upon these, e.g. as those described herein.

[0140] The length of the pressure measuring line 105 (from the connector 107) to the blood chamber 103 is exemplarily between 16.5 and 27.5 cm; preferably 22 cm; the outer diameter is, for example, 5.5 mm; the inner diameter 3.5 mm; the hose material is preferably PVC (polyvinyl chloride). Preferably, a durable bonding of the pressure measuring line 105 is chosen in a socket on the connector 107.

[0141] Preferably, the connector 107 of the free end is the female half of a Luer-lock-connector with a female Luer-cone and surrounding external thread.

[0142] Preferably, the diameter of the smallest free flow cross section in the female Luer-cone is 2.5 mm; the Luer-cone material is preferably PBT (polybutylene terephthalate).

[0143] Preferably, the air-permeable membrane 109 has a free flow diameter in the connector 107, from 10 to 14 mm, ideally 12 mm, that is preferably perpendicular to the flow-direction. The thickness of the air-permeable membrane 109 is preferably for example, around 0.15 mm.

[0144] The average pore diameter of the air-permeable membrane 109 (the material of which may be of, amongst others, PTFE (polytetrafluorethylene)), is preferably between 0.1 μm and 0.6 μm, ideally 0.2 μm (micrometre).

[0145] The membrane 109 is optionally supported in the connector 107 by radial support ribs, preferably on both sides, to guarantee the air permeability of all of the free cross section and to support the membrane against high pressure.

[0146] The machine side compressed air outlet 1001 may be a male half of the Luer-lock-connector with a male Luer-cone and surrounding union nut. It may, advantageously, be completely hygienic as made from stainless steel it is easy to clean.

LIST OF REFERENCE NUMERALS

[0147] 100 blood tubing set blood circuit [0148] 101 venous patient line [0149] 103 bubble/trap, bubble chamber, drip chamber or, in particular venous, blood chamber [0150] 105 pressure measuring line [0151] 105a first lumen section [0152] 105a′ first lumen section [0153] 105a″ first lumen section [0154] 105b second lumen section [0155] 105b′ second lumen section [0156] 105b″ second lumen section [0157] 107 connector [0158] 109 air-permeable membrane [0159] 1000 blood treatment apparatus [0160] 1001 compressed air outlet [0161] 1003 compressed air device, e.g. compressor [0162] 1005 compressed air line [0163] 1007 pressure sensor [0164] 1009 switch valve [0165] 1011 protective filter [0166] 1013 air-permeable membrane [0167] 1300 detection device [0168] 1500 pressure measuring unit [0169] h height [0170] P pressure measured [0171] t time [0172] V air volume