WO2014106010A1

WO2014106010A1 - Pressure-based leak detection in extracorporeal blood treatment apparatus

Info

Publication number: WO2014106010A1
Application number: PCT/US2013/077928
Authority: WO
Inventors: John O'mahony
Original assignee: Gambro Renal Products, Inc.
Priority date: 2012-12-31
Filing date: 2013-12-27
Publication date: 2014-07-03
Also published as: WO2014106010A9; CN104394900A

Abstract

The extracorporeal blood treatment apparatus described herein include components configured to detect liquid leaking from one or more liquid circuits in the extracorporeal blood treatment apparatus and methods of detecting liquid leaks in extracorporeal blood treatment apparatus. The components used to detect leaks include one or more remote pressure ports connected to one or more local pressure ports on one or more pressure sensors by one or more fluid-filled pressure lines. The fluid in the pressure lines transmits pressure exerted on a remote pressure port by any collected liquid to the local pressure port of the pressure sensor.

Description

PRESSURE-BASED LEAK DETECTION IN AN EXTRACORPOREAL BLOOD

TREATMENT APPARATUS

CROSS-REFERENCE

This application claims the benefit of U.S. Provisional Application Serial No.

61/747,718, filed December 31, 2012, the disclosure of which is incorporated herein by reference.

Extracorporeal blood treatment apparatus incorporating components for pressure-based leak detection and methods of using the same are described herein

BACKGROUND

Extracorporeal blood treatment involves taking the blood from a patient, treating the blood outside the patient, and returning the treated blood to the patient. Extracorporeal blood treatment is typically used to extract undesirable matter or molecules from the patient's blood, and/or to add beneficial matter or molecules to the blood. Extracorporeal blood treatment is used with patients incapable of effectively eliminating matter from their blood, for example in the case of a patient who is suffering from temporary or permanent kidney failure. These and other patients may undergo extracorporeal blood treatment to add to or to eliminate matter from their blood, to maintain an acid-base balance or to eliminate excess body fluids, for instance.

Extracorporeal blood treatment is typically performed by sampling the patient's blood in a continuous flow, by introducing the blood into a blood chamber of a filter that is defined, at least in part, by a semi-permeable membrane. The semi-permeable membrane may selectively allow the unwanted matter contained in the blood pass through the membrane, from the blood chamber to the secondary chamber, and may selectively allow the beneficial matter contained in the liquid going into the secondary chamber pass through the membrane to the blood going into the blood chamber, according to the type of treatment.

1

REPLACEMENT PAGE A number of extracorporeal blood treatments may be performed by the same machine. In ultrafiltration (UF) treatment, the unwanted matter is eliminated from the blood by convection through the membrane in the secondary chamber.

In hemofiltration (HF) treatment, the blood runs through a chamber that is defined, at least in part, by a semi-permeable membrane as in UF, and the beneficial matter is added to the blood, typically by the introduction of a fluid into the blood, either before, or after its passage through the filter and before it is returned to the patient.

In hemodialysis (HD) treatment, a secondary fluid containing the beneficial matter is introduced into the filter's secondary chamber. The blood's unwanted matter crosses the semi-permeable membrane by diffusion and penetrates into the secondary fluid, and the beneficial matter of the secondary fluid can cross the membrane and penetrate into the blood.

In hemodiafiltration (HDF) treatment, the blood and the secondary fluid exchange their matter as in HD, and further, matter is added to the blood, typically by introducing a fluid into the treated blood before it is returned to the patient as in HF; unwanted matters are eliminated from the blood by convection and diffusion.

In those treatments using a secondary fluid, the secondary fluid goes through the filter's secondary chamber and receives the blood's unwanted matter by diffusion and/or convection through the membrane. This liquid is then extracted from the filter: it is commonly called effluent, and is sent to a drain or to a receptacle then intended to be discharged into a drain.

The extracorporeal blood treatment apparatus used to accomplish these therapies typically includes numerous components such as: pumps, valves, tubes, sensors etc., which are connected to one another to form a number of liquid circuits. During use of the apparatus, an undesirable liquid leak from one or more of the liquid circuits might occur at one or more of the junctions between the various components or due to breakage or malfunction of one or more components.

Although the liquid circuits found in extracorporeal blood treatment apparatus are designed to function in all operating conditions without leaking, In some instances, one or more of the liquid circuits in the extracorporeal blood treatment apparatus can potentially leak. Apart from causing undesirable losses of material, leaks in the liquid circuits in an extracorporeal blood treatment apparatus can damage the apparatus and may compromise the therapy being delivered to a patient.

SUMMARY

The extracorporeal blood treatment apparatus described herein include components configured to detect liquid leaking from one or more liquid circuits in the extracorporeal blood treatment apparatus and methods of detecting liquid leaks in extracorporeal blood treatment apparatus. The components used to detect leaks include a remote pressure port connected to a local pressure port on a pressure sensor by a fluid-filled pressure line. The fluid in the pressure line transmits pressure exerted on the remote pressure port by any collected liquid to the local pressure port of the pressure sensor.

In one or more embodiments, separating the remote pressure port from the pressure sensor by a fluid-filled pressure line allows the pressure sensor to be electrically connected to a control unit without requiring that electrical connection to extend to the remote pressure port at which the leaked liquid is collected. Rather, the pressure exerted on the remote pressure port is communicated to a local pressure port of the pressure sensor by a fluid- filled pressure line.

In one or more embodiments, the pressure sensor may be located in the same housing as a control unit, while the fluid- filled pressure line extends out of the housing to a liquid collector at which the remote pressure port is located. The shortened electrical connection between the pressure sensor and a control unit may be advantageous because electrical interference that could potentially be caused by a longer electrical connections extending from the remote pressure port to the control unit (particularly in an extracorporeal blood treatment apparatus in which the location at which leaked liquid is collected is remote from the housing of the apparatus). For example, the leaked liquid may be detected at the base of the apparatus while the housing is located above the base by a distance of, e.g., one meter or more.

In one or more embodiments, the extracorporeal blood treatment apparatus described herein may include a single remote pressure port connected to a local pressure port on a pressure sensor by a single fluid-filled pressure line. In one or more alternative embodiments, the extracorporeal blood treatment apparatus described herein may include two or more remote pressure ports connected to two or more local pressure ports on one ore more pressure sensors, with each remote pressure port connected to its respective local pressure port by a dedicated fluid- filled pressure line. In such an embodiment, the remote pressure ports may be arranged to detect differential pressure between the two remote pressure ports and use the differential pressure as the basis for a determination that a leak has occurred within the extracorporeal blood treatment apparatus.

Although described herein in connection with extracorporeal blood treatment apparatus configured to perform dialysis using dialysate solutions, similar issues may be encountered in any extracorporeal blood treatment apparatus. For purposes of the discussions herein, the leak detection apparatus may be incorporated into any extracorporeal blood treatment apparatus, e.g., extracorporeal blood treatment apparatus using replacement fluid for convective replacement therapy of the renal function; plasma, albumin or colloid solutions for Therapeutic Plasma Exchange (TPE), or any other known type of medical fluid used in connection with an extracorporeal blood treatment apparatus.

In one aspect, one or more embodiments of the extracorporeal blood treatment apparatus described herein include: a housing; a liquid circuit on or in the housing, wherein the liquid circuit comprises one or more pumps and tubing configured to move blood through the liquid circuit for extracorporeal blood treatment; a liquid collector configured to collect liquid leaking from the liquid circuit; wherein the liquid leaking from the liquid circuit reaches the liquid collector under the force of gravity; and a pressure sensor comprising a local pressure port located on or in the housing, a remote pressure port located at a selected location in the liquid collector above which liquid collected by the collector accumulates, and a pressure line extending from the remote pressure port to the local pressure port, wherein the local pressure port is positioned in the liquid collector such that liquid collected at the selected location in the liquid collector contacts the remote pressure port, and wherein the pressure line is configured to transmit pressure exerted on the remote pressure port to the local pressure port through fluid located in the pressure line. The apparatus further includes a control unit operably connected to the pressure sensor, wherein the control unit is configured to: receive a signal from the pressure sensor, wherein the signal is indicative of pressure sensed by the remote pressure port of the pressure sensor; and make a determination that liquid is leaking from the liquid circuit when the pressure sensed by the remote pressure port reaches or exceeds a selected pressure limit.

In one or more embodiments of the extracorporeal blood treatment apparatus described herein, the pressure line is connected to the remote pressure port by a fluid-tight connector.

In one or more embodiments of the extracorporeal blood treatment apparatus described herein, the pressure line is connected to the local pressure port by a fluid- tight connector.

In one or more embodiments of the extracorporeal blood treatment apparatus described herein, the fluid in the pressure line consists essentially of one or more gases.

In one or more embodiments of the extracorporeal blood treatment apparatus described herein, the fluid in the pressure line consists essentially of one or more liquids.

In one or more embodiments of the extracorporeal blood treatment apparatus described herein, the pressure sensor comprises: a second remote pressure port configured to measure atmospheric pressure at a second selected location; and a second pressure line extending from the second remote pressure port to a second local pressure port of the pressure sensor, wherein the second pressure line is configured to transmit pressure exerted on the second remote pressure port to the second local pressure port through fluid located in the second pressure line; and wherein the control unit is configured to make a determination that liquid is leaking from the liquid circuit when the difference in pressure sensed by the remote pressure port and the second remote pressure port reaches or exceeds a selected value. In one or more embodiments, the second selected location is positioned at a selected height relative to the second local pressure port, and wherein the remote pressure port located at the selected location in the liquid collector is also at the selected height relative to the local pressure port to which it is connected. In one or more embodiments, the fluid in the second pressure line consists essentially of one or more gases. In one or more embodiments, the fluid in the second pressure line consists essentially of one or more liquids.

In one or more embodiments of the extracorporeal blood treatment apparatus described herein, the control unit is operably connected to a pump of the one or more pumps of the liquid circuit and wherein the control unit is configured to halt operation of the pump when the control unit determines that the liquid circuit is leaking.

In a second aspect, one or more embodiments of methods of detecting a leak in an extracorporeal blood treatment apparatus as described herein may include: pumping liquid through a liquid circuit located on or in a housing, the liquid circuit comprising one or more pumps and tubing configured to perform extracorporeal blood treatment; collecting liquid leaking from the liquid circuit in a liquid collector positioned below the housing; detecting pressure exerted on a remote pressure port of a pressure sensor by liquid collected in the liquid collector, wherein the pressure sensor is located on or in the housing, and wherein the remote pressure port is located at a selected location in the liquid collector; transmitting the pressure detected at the remote pressure port to a local pressure port of the pressure sensor using a pressure line extending from the remote pressure port to the local pressure port, wherein the pressure line transmits the pressure from the remote pressure port to the local pressure port through fluid located in the pressure line; and determining that liquid is leaking from the liquid circuit when the pressure sensed by the remote pressure port reaches or exceeds a selected pressure limit.

In a second aspect, one or more embodiments of methods of detecting a leak in an extracorporeal blood treatment apparatus as described herein may include: pumping liquid through a liquid circuit located on or in a housing, the liquid circuit comprising one or more pumps and tubing configured to perform extracorporeal blood treatment; collecting liquid leaking from the liquid circuit in a liquid collector positioned below the housing; detecting pressure exerted on a first remote pressure port by liquid collected in the liquid collector, wherein the first remote pressure port is located at a first selected location in the liquid collector, and wherein liquid collected by the collector accumulates above the first remote pressure port; transmitting the pressure detected at the first remote pressure port to a first local pressure port of a pressure sensor located on or in the housing using a first pressure line extending from the first remote pressure port to the first local pressure port, wherein the first pressure line transmits the pressure from the first remote pressure port to the first local pressure port through fluid located in the first pressure line; detecting atmospheric pressure acting on a second remote pressure port; transmitting the atmospheric pressure detected at the second remote pressure port to a second local pressure port of the pressure sensor using a second pressure line extending from the second remote pressure port to the second local pressure port, wherein the second pressure line transmits the pressure from the second remote pressure port to the second local pressure port through fluid located in the second pressure line; and determining that liquid is leaking from the liquid circuit when the difference in pressure sensed by the first remote pressure port and the second remote pressure port reaches or exceeds a selected value. In one or more embodiments, the second remote pressure port is positioned at a selected height relative to the second local pressure port, and wherein the first remote pressure port is also at the selected height relative to the first local pressure port.

In one or more embodiments of the methods described herein, the fluid in the pressure line consists essentially of one or more gases.

In one or more embodiments of the methods described herein, the method further comprises stopping a pump of the one or more pumps in the liquid circuit after determining that liquid is leaking from the liquid circuit.

As used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a" or "the" component may include one or more of the components and equivalents thereof known to those skilled in the art. Further, the term "and/or" means one or all of the listed elements or a combination of any two or more of the listed elements.

It is noted that the term "comprises" and variations thereof do not have a limiting meaning where these terms appear in the accompanying description.

Moreover, "a," "an," "the," "at least one," and "one or more" are used

interchangeably herein. The above summary is not intended to describe each embodiment or every implementation of the extracorporeal blood treatment apparatus and methods described herein. Rather, a more complete understanding of the invention will become apparent and appreciated by reference to the following Description of Illustrative Embodiments and claims in view of the accompanying figures of the drawing.

BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWING

FIG. 1 depicts one illustrative embodiment of an extracorporeal blood treatment apparatus configured to detect leaks using pressure-based leak detection as described herein

FIG. 2 is a schematic depiction of one illustrative embodiment of an extracorporeal blood treatment apparatus that includes a liquid circuit as described herein.

FIG. 3 is a schematic depiction of another illustrative embodiment of an extracorporeal blood treatment apparatus as described herein.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following description of illustrative embodiments, reference is made to the accompanying figures of the drawing which form a part hereof, and in which are shown, by way of illustration, specific embodiments. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.

One illustrative embodiment of an extracorporeal blood treatment apparatus is depicted in FIG. 1. The extracorporeal blood treatment apparatus 1 is, in one or more embodiments, a dialysis machine for treatment of renal insufficiency which may be able to perform one or more of the following treatments: hemodialysis, pure ultrafiltrat on, emofiltration, hemodiafiltration, therapeutic plasma exchange, etc.

In the embodiment depicted in FIG, 1 , the apparatus 1 is especially suitable for intensive treatment of acute kidney failure and includes a blood treatment device 2 (e.g., dialyzer filter) and a fluid distribution circuit 3 capable of delivering fluid (e.g., blood, dialysate solution, etc.) to the blood treatment device 2. For the sake of simplicity and clarity of the drawing, only the support for the fluid distribution circuit 3 is shown in FIG. 1.

The extracorporeal blood treatment apparatus 1 also includes one or more pumps 4 used to circulate fluids within the fluid distribution circuit 3. The fluid distribution circuit 3 may be configured to move blood to and from a patient, as well as fluids that are supplied by and/or delivered to the reservoirs 6 that, in the depicted embodiment, hang from the bottom end 13 of the housing 12 of the extracorporeal blood treatment apparatus 1. The reservoirs 6 are depicted in the form of bags, although any other suitable container for the fluids contained therein may be used in place of bags.

The extracorporeal blood treatment apparatus 1 depicted in FIG. 1 also includes a base 14 above which the housing 12 is supported by a column 16. The base 14 includes a liquid collector 20 that is positioned below the bottom and 13 of the housing 12. The collector 20 is shaped to collect liquid leaking from a liquid circuit in or on the housing 12 of the extracorporeal blood treatment apparatus I located above the base 14. The surfaces of the collector 20 are shaped and or angled to collect liquid in one area of the collector 20 regardless of the position at which the liquid first contacts the collector 20. In the embodiment depicted in FIG. 1, for example, the collector 20 include surfaces that are designed to direct liquid towards a collection area 23 that sits below the remainder of the collector 20.

Also seen in the embodiment of extracorporeal blood treatment apparatus 1 depicted in FIG. 1 are remote pressure ports 22 that are used in combination with pressure sensors as described herein to detect leakage from the extracorporeal blood treatment apparatus 1. Although two remote pressure ports 22 are depicted in the embodiment of FIG. 1, in one or more other embodiments, as will be described herein, for example, as few as one remote pressure port may be used to perform the leak detection functions of the apparatus described herein.

FIG. 2 is a schematic depiction of one illustrative embodiment of an extracorporeal blood treatment apparatus that includes a liquid circuit as described herein. One portion of the depicted liquid circuit includes a blood pump 4a that is configured to move blood removed from a patient P using an arterial line 7 and deliver it to blood treatment device 2 using, e.g., a blood pump 4a. The liquid circuit depicted in FIG. 2 further includes a venous line 8 used to return blood to the patient P from the filter 2. Another portion of the liquid circuit depicted in FIG. 2 includes a dialysate pump 4b used to deliver dialysate from a reservoir 6a into the blood treatment device 2 through the delivery line 9 and to remove the used dialysate from the blood treatment device 2 through waste line 10 and deliver it to a reservoir 6b.

Also depicted in the illustrative embodiment of an extracorporeal blood treatment apparatus of FIG. 2 is a collector 20 that is large enough and positioned properly to collect liquid leaking from the liquid circuits found in or on the extracorporeal blood treatment apparatus 1. The collector 20 preferably includes sloped or angled surfaces such that liquids falling into the collector 20 are directed to and accumulate above a location at which a remote pressure port 22 is positioned. The remote pressure port 22 is connected to a local pressure port 26 on the pressure sensor 28 through pressure line 24.

Liquid collected in the collector 20 exerts pressure on the remote pressure port 22 and that pressure is communicated to the local pressure port 26 on the pressure sensor 28 through fluid-filled pressure line 24. As discussed herein, the use of a fluid-filled pressure line 24 to communicate pressure exerted on the remote pressure port 22 by liquid collected in the collector 20 to a local pressure port 26 on pressure sensor 28 can reduce or eliminate the potential for electrical interference that would be caused by an electrical connection extending over the same pathway as the fluid-filled pressure line 24.

In one or more embodiments, the remote pressure port 22 may include a membrane or other structures such that liquid collected in the collector 20 is prevented from entering the remote pressure port 22 in a manner that would allow it to mix with or enter the fluid-filled pressure line 24.

In one or more embodiments of the extracorporeal blood treatment apparatus described herein, fluid-filled pressure line 24 used to communicate pressure from the remote pressure port 22 to the local pressure port 26 of the pressure sensor 28 may be connected to remote pressure port 22 by a connector 23 and to the local pressure port 26 on the pressure sensor 28 by connector 27. The connectors 23 and 27 may be the same or different and may take a variety of forms, e.g., a Luer lock connection, a bayonet mount, a hose clamp and nipple, or any other suitable connection that can transmit pressure as needed between the fluid in the pressure line 24 and the leaked liquid at the remote pressure port 22 and between the fluid in the pressure line 24 and the local pressure port 26.

In one or more embodiments of the extracorporeal blood treatment apparatus described herein, the fluid in the pressure line 24 may be any suitable fluid capable of transmitting pressure exerted on the remote pressure port 22 to the local pressure port 26 on the pressure sensor 28 with acceptable accuracy. Examples of some potentially suitable fluids for use in the fluid- filled pressure line 24 may include, e.g., air, nitrogen, saline solution, gels, water, etc. In one or more embodiments, the fluid- filled pressure lines used in the extracorporeal blood treatment apparatus described herein may be filled with either gas only (e.g., the fluid in the pressure line consists essentially of one or more gases such as air, nitrogen, etc.) or they may be filled only with a liquid (e.g., the fluid in the pressure line may consist essentially of one or more liquids).

Another component depicted in connection with the illustrative embodiment of extracorporeal blood treatment apparatus 1 in FIG. 2 is a control unit 30. The blood pump 4a and the dialysate solution pump 4b are, in the depicted embodiment, both operably connected to the control unit 30. In addition, the pressure sensor 28, which is connected to remote pressure port 22 by fluid-filled pressure line 24, is also operably connected to the control unit 30.

The control unit 30 is configured to receive a signal from the pressure sensor 28. The signal from the pressure sensor 28 is indicative of the pressure sensed at the remote pressure port 22 connected to the local pressure port 26 on the pressure sensor 28 by a fluid-filled pressure line 24. If the signal received by the control unit 30 from the pressure sensor 28 indicates that the pressure sensed at the remote pressure port 22 exceeds a selected limit, then a determination can be made that liquid is leaking from a liquid circuit in the extracorporeal blood treatment apparatus 1.

The selected limit may be a function of the volume of liquid in the collector

20 which is related to the height of the liquid in the collector 20 above the remote pressure port 22. In particular, the pressure (P) at the remote pressure port 22 is a function of P = p * g * h where p= density of the liquid, g = acceleration due to gravity and h = height of liquid above the remote pressure port 22.

If that determination is made, the extracorporeal blood treatment apparatus 1 may be configured to provide an indication to an operator in the form of an alarm or other signal and, in one or more embodiments, may also result in terminating operation of one or more of the pumps that are operably connected to the control unit. In addition, if the extracorporeal blood treatment apparatus includes valves, clamps, etc. that can be selectively closed, a determination that a leak is occurring within the extracorporeal blood treatment apparatus may also cause the control unit to initiate closure of the valves, clamps, etc. if such action is warranted.

The control units used in the extracorporeal blood treatment apparatus described herein may be provided in any suitable form and may, for example, include memory and a controller. The controller may, for example, be in the form of one or more microprocessors, Application Specific Integrated Circuit (ASIC) state machines, etc. The control units may include one or more of any suitable input devices configured to allow a user to operate the apparatus (e.g., keyboards, touchscreens, mice, trackballs, etc.), as well as display devices configured to convey information to a user (e.g., monitors (which may or may not be touchscreens), indicator lights, etc.).

Another alternative illustrative embodiment of an extracorporeal blood treatment apparatus 101 is depicted in FIG. 3. Among the components depicted in the schematic diagram of FIG. 3 as forming a part of the extracorporeal blood treatment apparatus 101, are a pump 104, pressure sensor 128, and control unit 130, all of which are depicted as being located within a housing 1 12 of the extracorporeal blood treatment apparatus 101. The extracorporeal blood treatment apparatus 101 depicted in FIG. 3 also includes a liquid collector 120 positioned and sized to collect liquid leaking from a liquid circuit within the extracorporeal blood treatment apparatus 101.

The pressure sensor 128 includes two local pressure ports 126a and 126b. A first remote pressure port 122a is connected to local pressure port 126a on the pressure sensor 128 by a fluid-filled pressure line 124a, while a second remote pressure port 122b is connected to the local pressure port 126b on the pressure sensor 128 by a second fluid- filled pressure line 124b.

The first remote pressure port 122a is positioned in the liquid collector 122 to detect pressure exerted on the remote pressure port 122a by liquid collected in the liquid collector 120. The second remote pressure port 122b is open to atmospheric pressure. In one or more embodiments, the second remote pressure port 126b is positioned at the same height h relative to the local pressure ports 126a and 126b as the first remote pressure port 122a. Doing so allows the system to both correct for atmospheric pressure changes and to cancel out the head pressure due to the fluid in the fluid-filled lines 124a and 124b. It should be noted that relative positional terms used herein, such as "above," "below," and "height" are measured along a direction of the force of gravity.

Although the local pressure ports 126a and 126b are, in the depicted embodiment, part of a single pressure sensor 128, in one or more alternative embodiments each of the local pressure ports may be connected to separate and independent pressure sensors with each independent pressure sensor being operably connected to the control unit 130.

Although methods of detecting leaks in an extracorporeal blood treatment apparatus are described in connection with the apparatus depicted in FIGS. 1-3, one or more embodiments of the methods of detecting a leak in an extracorporeal blood treatment apparatus as described herein may include pumping liquid through a liquid circuit located on or in a housing of an extracorporeal blood treatment apparatus.

The liquid circuit may include, as described herein, one or more pumps and tubing configured to perform extracorporeal blood treatment. Liquid leaking from the liquid circuit may be collected in a liquid collector positioned below the housing of the extracorporeal blood treatment apparatus.

In one or more embodiments, the methods may include detecting pressure exerted on a remote pressure port of a pressure sensor by the liquid collected in the liquid collector. The pressure sensor is located on or in the housing and the remote pressure port is located at a selected location in the liquid collector. The pressure exerted on the remote pressure port is transmitted to a local pressure port of the pressure sensor using a pressure line extending from the remote pressure port to the local pressure port. The pressure line transmits the pressure from the remote pressure port to the local pressure port through fluid located in the pressure line.

When the pressure exerted on the remote pressure port by the liquid collected in the leak collector reaches or exceeds a selected pressure limit, the method further includes determining that liquid is leaking from the liquid circuit.

In one or more alternative embodiments of the methods of detecting leaks as described herein, detecting pressure exerted by the leaked liquid collected in the liquid collector may include detecting pressure exerted on a first remote pressure port of a pressure sensor by liquid collected in the liquid collector. The pressure sensor is located on or in the housing of the extracorporeal blood treatment apparatus. The first remote pressure port is located at a first selected location in the liquid collector. The pressure detected at the first remote pressure port is transmitted to a first local pressure port of the pressure sensor using a first pressure line extending from the first remote pressure port to the first local pressure port. The first pressure line transmits the pressure from the first remote pressure port to the first local pressure port through fluid located in the first pressure line.

This method may also include detecting atmospheric pressure exerted on a second remote pressure port that is connected to a second local pressure port on the pressure sensor by a second fluid-filled line. As a result, the pressure exerted on the first remote pressure sensor can be adjusted to account for changes in atmospheric pressure. The second remote pressure port may, in one or more embodiments, be positioned at the same height, relative to the local pressure ports on the pressure sensor, as the first pressure port. As a result, the pressure exerted on the first remote pressure port can also be adjusted for the head pressure due to the fluid in the fluid- filled pressure lines connecting the first and second remote pressure ports to the pressure sensor.

Methods involving the detection of pressure at such first and second remote pressure ports includes determining that liquid is leaking from the liquid circuit when the difference in pressure sensed by the first remote pressure port and the second remote pressure port reaches or exceeds a selected value.

In one or more embodiments of the methods of detecting leaks in a liquid circuit of an extracorporeal blood treatment apparatus as described herein, the fluid in the pressure line used to transmit pressure from a remote pressure port to a local pressure port consists essentially of one or more gases.

In one or more embodiments of the methods of detecting leaks in a liquid circuit of an extracorporeal blood treatment apparatus as described herein, the fluid in the pressure line used to transmit pressure from a remote pressure port to a local pressure port consists essentially of one or more liquids.

In one or more embodiments of the methods of detecting leaks in a liquid circuit of an extracorporeal blood treatment apparatus as described herein, the method may include stopping a pump of the one or more pumps in the liquid circuit after determining that liquid is leaking from the liquid circuit.

The complete disclosure of the patents, patent documents, and publications identified herein are incorporated by reference in their entirety as if each were individually incorporated.

Illustrative embodiments of the blood treatment apparatus and methods of using the same are discussed and reference has been made to possible variations. These and other variations and modifications in the invention will be apparent to those skilled in the art without departing from the scope of the invention, and it should be understood that this invention is not limited to the illustrative embodiments set forth herein. Accordingly, the invention is to be limited only by the claims provided below and equivalents thereof.

Claims

CLAIMS:

What is claimed is: 1. An extracorporeal blood treatment apparatus that comprises:

a housing;

a liquid circuit on or in the housing, wherein the liquid circuit comprises one or more pumps and tubing configured to move blood through the liquid circuit for extracorporeal blood treatment;

a liquid collector configured to collect liquid leaking from the liquid circuit; wherein the liquid leaking from the liquid circuit reaches the liquid collector under the force of gravity;

a pressure sensor comprising a local pressure port located on or in the housing, a remote pressure port located at a selected location in the liquid collector above which liquid collected by the collector accumulates, and a pressure line extending from the remote pressure port to the local pressure port, wherein the local pressure port is positioned in the liquid collector such that liquid collected at the selected location in the liquid collector contacts the remote pressure port, and wherein the pressure line is configured to transmit pressure exerted on the remote pressure port to the local pressure port through fluid located in the pressure line; and a control unit operably connected to the pressure sensor, wherein the control unit is configured to:

receive a signal from the pressure sensor, wherein the signal is indicative of pressure sensed by the remote pressure port of the pressure sensor; and

make a determination that liquid is leaking from the liquid circuit when the pressure sensed by the remote pressure port reaches or exceeds a selected pressure limit.

2. An apparatus according to claim 1, wherein the pressure line is connected to the remote pressure port by a fluid-tight connector.

3. An apparatus according to either of claims 1 and 2, wherein the pressure line is connected to the local pressure port by a fluid-tight connector.

4. An apparatus according to any one of claims 1 to 3, wherein the fluid in the pressure line consists essentially of one or more gases.

5. An apparatus according to any one of claims 1 to 3, wherein the fluid in the pressure line consists essentially of one or more liquids.

6. An apparatus according to any one of claims 1 to 5, wherein the pressure sensor comprises:

a second remote pressure port configured to measure atmospheric pressure at a second selected location; and

a second pressure line extending from the second remote pressure port to a second local pressure port of the pressure sensor, wherein the second pressure line is configured to transmit pressure exerted on the second remote pressure port to the second local pressure port through fluid located in the second pressure line;

and wherein the control unit is configured to make a determination that liquid is leaking from the liquid circuit when the difference in pressure sensed by the remote pressure port and the second remote pressure port reaches or exceeds a selected value.

7. An apparatus according to claim 6, wherein the second selected location is positioned at a selected height relative to the second local pressure port, and wherein the remote pressure port located at the selected location in the liquid collector is also at the selected height relative to the local pressure port to which it is connected.

8. An apparatus according to any one of claims 6 to 7, wherein the fluid in the second pressure line consists essentially of one or more gases.

9. An apparatus according to any one of claims 6 to 7, wherein the fluid in the second pressure line consists essentially of one or more liquids.

10. An apparatus according to any one of claims 1 to 9, wherein the control unit is operably connected to a pump of the one or more pumps of the liquid circuit and wherein the control unit is configured to halt operation of the pump when the control unit determines that the liquid circuit is leaking.

11. A method of detecting a leak in an extracorporeal blood treatment apparatus, the method comprising:

pumping liquid through a liquid circuit located on or in a housing, the liquid circuit comprising one or more pumps and tubing configured to perform

extracorporeal blood treatment;

collecting liquid leaking from the liquid circuit in a liquid collector positioned below the housing;

detecting pressure exerted on a remote pressure port of a pressure sensor by liquid collected in the liquid collector, wherein the pressure sensor is located on or in the housing, and wherein the remote pressure port is located at a selected location in the liquid collector;

transmitting the pressure detected at the remote pressure port to a local pressure port of the pressure sensor using a pressure line extending from the remote pressure port to the local pressure port, wherein the pressure line transmits the pressure from the remote pressure port to the local pressure port through fluid located in the pressure line; and

determining that liquid is leaking from the liquid circuit when the pressure sensed by the remote pressure port reaches or exceeds a selected pressure limit.

12. A method of detecting a leak in an extracorporeal blood treatment apparatus, the method comprising:

extracorporeal blood treatment; collecting liquid leaking from the liquid circuit in a liquid collector positioned below the housing;

detecting pressure exerted on a first remote pressure port by liquid collected in the liquid collector, wherein the first remote pressure port is located at a first selected location in the liquid collector, and wherein liquid collected by the collector accumulates above the first remote pressure port;

transmitting the pressure detected at the first remote pressure port to a first local pressure port of a pressure sensor located on or in the housing using a first pressure line extending from the first remote pressure port to the first local pressure port, wherein the first pressure line transmits the pressure from the first remote pressure port to the first local pressure port through fluid located in the first pressure line;

detecting atmospheric pressure acting on a second remote pressure port; transmitting the atmospheric pressure detected at the second remote pressure port to a second local pressure port of the pressure sensor using a second pressure line extending from the second remote pressure port to the second local pressure port, wherein the second pressure line transmits the pressure from the second remote pressure port to the second local pressure port through fluid located in the second pressure line; and

determining that liquid is leaking from the liquid circuit when the difference in pressure sensed by the first remote pressure port and the second remote pressure port reaches or exceeds a selected value.

13. A method according to claim 12, the second remote pressure port is positioned at a selected height relative to the second local pressure port, and wherein the first remote pressure port is also at the selected height relative to the first local pressure port.

14. A method according to any one of claims 11 to 13, wherein the fluid in the pressure line consists essentially of one or more gases.

15. A method according to any one of claims 11 to 14, wherein the method further comprises stopping a pump of the one or more pumps in the liquid circuit after determining that liquid is leaking from the liquid circuit.