U.S. patent application number 11/577126 was filed with the patent office on 2010-04-22 for blood treatment dialyzer/filter design to trap entrained air in a fluid circuit.
This patent application is currently assigned to NXSTAGE MEDICAL, INC. Invention is credited to James M. Brugger.
Application Number | 20100096311 11/577126 |
Document ID | / |
Family ID | 36319501 |
Filed Date | 2010-04-22 |
United States Patent
Application |
20100096311 |
Kind Code |
A1 |
Brugger; James M. |
April 22, 2010 |
BLOOD TREATMENT DIALYZER/FILTER DESIGN TO TRAP ENTRAINED AIR IN A
FLUID CIRCUIT
Abstract
A modification in the configuration of the blood microtubular
filter/dializer used in many kinds of renal replacement therapy
systems can provide highly a effective mechanism for removing air
from the blood circuit of such systems. In embodiments, for
example, the invention takes advantage of the slow flow rate that
usually occurs where blood exits the microtubules into a header
area of the filter to provide a settling area and, preferably, a
air relief mechanism.
Inventors: |
Brugger; James M.;
(Newburyport, MA) |
Correspondence
Address: |
MILES & STOCKBRIDGE PC
1751 PINNACLE DRIVE, SUITE 500
MCLEAN
VA
22102-3833
US
|
Assignee: |
NXSTAGE MEDICAL, INC
Lawrence
MA
|
Family ID: |
36319501 |
Appl. No.: |
11/577126 |
Filed: |
September 16, 2005 |
PCT Filed: |
September 16, 2005 |
PCT NO: |
PCT/US2005/036603 |
371 Date: |
December 18, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60622863 |
Oct 28, 2004 |
|
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Current U.S.
Class: |
210/198.1 ;
210/249; 210/321.72; 210/321.78; 210/321.87; 210/435; 210/436 |
Current CPC
Class: |
B01D 61/20 20130101;
B01D 63/00 20130101; B01D 63/02 20130101; B01D 19/0021 20130101;
B01D 2313/18 20130101; A61M 1/3627 20130101; B01D 2313/06 20130101;
B01D 65/00 20130101; B01D 19/0042 20130101; B01D 61/30
20130101 |
Class at
Publication: |
210/198.1 ;
210/321.72; 210/249; 210/435; 210/321.87; 210/321.78; 210/436 |
International
Class: |
B01D 61/28 20060101
B01D061/28; B01D 63/00 20060101 B01D063/00; B01D 35/01 20060101
B01D035/01; B01D 63/06 20060101 B01D063/06; B01D 69/00 20060101
B01D069/00; B01D 35/30 20060101 B01D035/30 |
Claims
1. A blood treatment apparatus, comprising: a blood processing
element including filter media through which blood passes; said
processing element having a header chamber at a position where
blood exits a portion of said blood processing element, said header
chamber having at least one outlet; a holder configured to support
said processing element in a position and orientation such that air
can accumulate in said header chamber in a position remote from
said outlet whereby said header chamber is enabled to remove air
from blood.
2. Apparatus as in claim 1, wherein said processing element is
attached to a fluid circuit and forms a part of a disposable
set.
3. Apparatus as in claim 1, wherein said holder is fixedly
attachable to a blood treatment machine.
4. Apparatus as in claim 1, wherein said holder is configured to
support said filter at an angle with respect to the vertical, as
defined with respect to the force of gravity.
5. Apparatus as in claim 1, wherein said processing element
includes tubular membrane media that are vertically oriented in
ordinary use.
6. A blood treatment apparatus, comprising: a blood dialyzer or
hemofilter processing element including filter media through which
blood passes; said processing element having a header chamber at a
position where blood exits a treatment portion of said blood
processing element, said header chamber having at least one blood
outlet and at least one auxiliary outlet; a holder configured to
support said dialyzer or hemofilter in a position and orientation
such that air can accumulate in said header chamber in a position
in said header space that is adjacent and in communication with
said auxiliary outlet.
7. Apparatus as in claim 6, wherein said auxiliary outlet is remote
from said blood outlet.
8. Apparatus as in claim 6, wherein said auxiliary outlet is
opposite said blood outlet.
9. Apparatus as in claim 6, further comprising a valve connected to
said auxiliary port and pre-connected and sterilized together with
said blood processing element.
10. Apparatus as in claim 6, further comprising a stopcock
connected to said auxiliary port and pre-connected and sterilized
together with said blood processing element.
11. Apparatus as in claim 6, further comprising a syringe connected
to said auxiliary port and pre-connected and sterilized together
with said blood processing element.
12. Apparatus as in claim 6, further comprising a holder configured
to orient said blood processing element such that said at least one
blood outlet is lower, with respect to a direction of gravity, than
said auxiliary outlet.
13. Apparatus as in claim 6, further comprising an gas release
component connected to said auxiliary port and pre-connected and
sterilized together with said blood processing element, said air
release component being configured to permit gas to egress from
said header space without permitting blood to egress from said
header space.
14. Apparatus as in claim 13, wherein said air release component
includes a hydrophobic membrane.
15. A blood treatment apparatus, comprising: a blood dialyzer or
hemofilter processing element including filter media through which
blood passes; said processing element having a chamber at an exit
of a treatment portion thereof where blood flow velocity drops to a
low rate, said chamber having at least one outlet; a holder
attachable to a blood treatment machine and configurable to support
said processing element in a position and orientation such that air
can accumulate in said header chamber in a position remote from
said outlet whereby said header chamber is enabled to remove air
from blood.
16. Apparatus as in claim 15, wherein said processing element is
attached to a fluid circuit and forms a part of a disposable
set.
17. Apparatus as in claim 16, wherein said holder is configured to
support said filter at an angle with respect to the vertical, as
defined with respect to the force of gravity.
18. Apparatus as in claim 15, wherein said holder is configured to
support said filter at an angle with respect to the vertical, as
defined with respect to the force of gravity.
19. Apparatus as in claim 15, wherein said processing element
includes tubular membrane media that are vertically oriented in
ordinary use.
20. A blood treatment apparatus, comprising: a blood processing
element including filter media through which blood passes; said
processing element having a header chamber at a position where
blood exits a portion of said blood processing element, said header
chamber having at least one blood outlet and one auxiliary outlet;
said auxiliary outlet being configured to permit the removal of air
accumulated in said header chamber and/or addition and removal of
biocompatible non-blood fluid.
21. Apparatus as in claim 20, further comprising a valve connected
to said auxiliary port and pre-connected and sterilized together
with said blood processing element.
22. Apparatus as in claim 20, further comprising a stopcock
connected to said auxiliary port and pre-connected and sterilized
together with said blood processing element.
23. Apparatus as in claim 20, further comprising a syringe
connected to said auxiliary port and pre-connected and sterilized
together with said blood processing element.
24. Apparatus as in claim 20, further comprising a holder
configured to orient said blood processing element such that said
at least one blood outlet is lower, with respect to a direction of
gravity, than said auxiliary outlet.
25. Apparatus as in claim 20, further comprising an gas release
component connected to said auxiliary port and pre-connected and
sterilized together with said blood processing element, said air
release component being configured to permit gas to egress from
said header space without permitting blood to egress from said
header space.
26. Apparatus as in claim 25, wherein said air release component
includes a hydrophobic membrane.
Description
BACKGROUND
[0001] One of the problems with fluid circuits in blood treatment
systems is entrained air (bubbles) in treatment fluids, infusate,
or blood. Treatment systems normally have air detectors to prevent
air from being injected into a patient, either because a venous
line carrying blood back to the patient contains air or because an
infusate line, such as the replacement fluid line of a
hemofiltration system, contains air. It is desirable for the air
detectors to be made sufficiently sensitive to prevent the rare
instances of long trains of air bubbles being injected into a
patient. But sensitivity high enough to prevent long thin trains of
bubbles may be high enough to alarm very small amounts of air which
pose no risk. In other words, sensitive air detectors alarm on a
lot of fall positives if they protect against all possible
risks.
[0002] To eliminate false positives, a prior art approach has been
to remove as much air from a protected fluid circuit as possible.
Putting air traps in fluid circuits, particularly blood lines, has
drawbacks. Air-settling chambers necessarily involve stagnant flow,
which creates a risk of forming clots (e.g., for blood) or
sedimentation or other concentration of entrained material (e.g.
medication).
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] FIG. 1 is a cross-section view of a filter usable in a
variety of different types of blood treatment systems oriented to
trap air in one or two header portions of the filter.
[0004] FIG. 2 illustrates a holder of a blood treatment machine to
orient the filter of FIG. 1.
[0005] FIG. 3 illustrates a filter similar to that of FIG. 1 but
with a header port for removing air and/or disrupting or cleaning
clots.
[0006] FIG. 4 illustrates an assembly for use with the port of FIG.
3 for removing air and/or disrupting or cleaning clots.
[0007] FIG. 5 illustrates a header cap with a hydrophobic membrane
for automatically venting air.
DETAILED DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a cross-section view of a filter usable in a
variety of different types of blood treatment systems oriented to
trap air in one or two header portions of the filter. A filter 100,
which may be a dialyzer, hemofilter, hemodiafilter, or any other
compatible blood treatment has a bundle of tubular media 132
connecting an arterial 160 and venous 155 head space which is
isolated from a filtrate space 130. Blood flows through ports 122
and 124 in header caps 110 and 136 as indicated by arrows 118 and
112 into and out of the arterial 160 and venous 155 head spaces,
respectively. A cylindrical filter body 128 encloses the filtrate
space 130 and contains filtrate (e.g., dialyzer) ports 126 and 120.
Arterial and venous headers 142 and 134 isolate the filtrate space
130 from the respective arterial 160 and venous 155 head
spaces.
[0009] The orientation of the filter 100 with respect to the pull
of gravity is shown with the understanding that gravity is assumed
to pull down with respect to the profile orientation of the drawing
page. If any air is entrained in the blood, it may settle in
pockets 151 and 153 in the arterial 160 and venous 155 head spaces
as indicated by air/liquid interfaces 152 and 150. The flow of
blood through the arterial 160 and venous 155 head spaces is
extremely slow due to the very small cross-sectional areas of the
filter fibers in the bundle 132. As a result, the arterial 160 and
venous 155 head spaces are an idea place for air to settle out.
With the indicated orientation, with blood outlet 124 pointing down
and away from the pocket 151. Since the blood moves at a very slow
rate in the arterial 160 and venous 155 head spaces, there is
little risk of reentrainment and air settles out very
effectively.
[0010] Air trapped in pocket 153 may travel through filter fibers
in bundle 132 up to venous head space 155 and accumulate in pocket
151. Since the pocket 153 is located near the top of the arterial
head space 160, air will tend to travel up a few of the fibers
closest to the top and collect in the pocket 151 without mixing in
with blood. This keeps the vast majority of fibers filled with
blood.
[0011] FIG. 2 illustrates a holder 175 of a blood treatment machine
to orient the filter of FIG. 1. The holder 175 may be attached at a
base thereof (not shown separately) to a blood treatment machine
172 which may contain actuators, sensors, and control elements as
well as a fluid circuit, here illustrated as a cartridge 180
enclosed between two parts 171 and 172 of the blood treatment
machine 172. A filter 100 that is preconnected to the fluid circuit
can easily be mounted in such an apparatus. The holder 175 may be
articulating to allow for some movement or change of orientation of
the filter 100 and is preferably a spring tensioned clamp that
allows for one-handed insertion of a filter 100. In an alternative
embodiment, the holder 175 may be attached to the 180 cartridge
such that its orientation is obtained when the cartridge 180 is
positioned with respect to the blood treatment machine 170.
[0012] FIG. 3 illustrates a filter similar to that of FIG. 1 but
with a header cap 210 having an integrated header port 200 for
removing air and/or disrupting or cleaning clots. Tubing 265 may be
connected to the port and provided with a clamp 260. The clamp 260
may be released, at intervals, by an operator, to vent air from the
air pocket 251 and re-engaged to prevent blood loss. The clamp 260
may be a normally-closed type clamp with a strong spring so that it
reclamps tubing 265 when released. The tubing 265 may be capped
with a microporous filter end cap 253 to prevent any contamination
re-entering the blood in the venous head space 155. The entire
assembly that includes the filter 100, tubing 265, and microporous
filter end cap 253 may be fused, sealed, and sterilized as a unit.
In addition the same may be fused, sealed and sterilized as a unit
with an entire treatment circuit, combining it with the circuit
described in U.S. patent application Ser. No. 10/650,935 published
as US 2004-0069709, which is hereby incorporated by reference as if
full set forth in its entirety herein. With this combination, the
entire circuit may be isolated from contamination.
[0013] FIG. 4 illustrates an assembly 350 for use with the port of
FIG. 3 for removing air and/or disrupting or cleaning clots. The
port 200 has a tube 310 connecting the venous head space 155 with a
stopcock 312. The stopcock 312 is further connected to a syringe
320 and tubing 375 connecting a supply of blood normal saline 375
and 360. The stopcock allows the syringe to be connected, in a
first position, to draw saline from the source of saline 375 and,
in a second position, air from the venous head space 155. In the
second position, saline may be pushed into the head space 155 to
clear clots or for prophylaxis by injecting heparin. In an
illustrative usage method, the stopcock 312 is set in the second
position and air is drawn from the head space 155. Then it is set
in the first position and saline is drawn into the syringe 320.
Then the stopcock 312 is set in the second position again and
saline (or saline and heparin) is injected into the venous head
space 155. The apparatus including the stopcock 312, syringe 320,
tubing 310, 375, 360 and clamp 260 may be pre-attached to the
filter 100 and presterilized as a unit.
[0014] FIG. 5 illustrates a header cap 210 with cover 280 sealed to
and covering the header port 200. The cover includes a hydrophobic
membrane 285 that allows air in the head space 155 to vent
automatically while preventing any contamination from entering.
* * * * *