Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
Hemodialysis apparatus for artificial kidneys
generally comprises a supported, semi~permeable membrane
made of a cellophane`type material, positioned in a
casing to provide a blood flow path along one side of the
membrane and a dialysis solution flow path along the
other side, for diffusion exchange across the membrane
between the blood and the dialysis solution without the
direct intermixing of the ~wo liquids.
In the actual hemodialysis process, a considerable
nu~ber of processing steps are required during the opera-
tion of bringing the blood to the hemodialyzer, and with- -
drawing it from the hemodialyzer for return to the patient.
In the presently-conventional arterial and venous sets
which are used to withdraw blood from a patient, convey
it to the dialyzer, and return it again to the patient,
bubble traps, filters, sterile access sites for injection
needles, and access sites for pressure monitor equipment
may all be included on the ~sets, which primarily comprise
flexible, blood compatible plastic tubing. Accordingly,
in the present technology of dialysis, two different and
separate long, tubular sets are utilized, the arterial
set upstream from the dialyzer in terms of blood flow,
and the ven~us set downstream from the dialyzer.
Hence, to set up a dialysis procedure, a dialyzer
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must be selected, and the nurse must also separately ob-
tain an arterial set and a venous set. The packaging
of all of these devices must be opened, and the devices
respectively must be connected and assembled together,
with other auxiliary equipment being also added to the
system. This requires the services of a highly trained
technician, who must make a considerable number of con-
nections between the sets and the dialyzer, flawlessly
and without error.
In accordance with this invention, a one-piece
hydraulic circuit member is provided to replace many of
the functions of the arterial inlet and outlet sets, and
auxiliary equipment. The one-piece hydraulic circuit
member may be connected to the dialyzer itself at the
time of manufacture, if desired. The set-up of the
dialysis system prior to use is thus greatly simplified,
eliminating many of the connections which must be made
by the technician at the site of use, which, in turn,
reduces the possibility of error, and contamination of
the system during the assembly and connection process.
Furthermore, the system of this invention is compact and
simplified, saving a considerable amount of valuable
space around the bed during the dialysis procedure.
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DESCRIPTION OF THE INVENTION
In accordance with the invention, there is pro-
vided an improvement in a hydraulic circuit member for
use with a membrane diffusion device. The member is
unitary and defines a plurality of blood-receiving cham-
bers, and conduit means communicating between said blood-
receiving chambers for directing, receiving, and processing
blood passing through said membrane diffusion device. At
least one of the blood-receiving chambers defines a
transversely-enlarged upper chamber portion connected by
a step wall which abruptly narrows the bottom end of the
enlarged chamber area to a lower portion of lesser
transverse dimension. Points of communication of said con-
duit means with said chamber are provided and include an inlet
spaced from the bottom of said chamber and communicating
directly with said enlarged upper chamber portion in an
upwardly-pointing direction through said step wall, and
an outlet positioned adjacent the end of the lower por-
tion remote from said enlarged upper end portion of the
chamber. The chamber defines a vent means for gasses
at its upper end and constituting an improved bubble
trap for blood when blood is introduced through the
inlet and withdrawn through the outlet.
The one-piece hydraulic circuit member may define
spaced first, second and third chambers therein. A first
port communicates with the first chamber, and is adapted
for connection with a venous line of a patient. A second
port also communicates with the first chamber, and is
adopted for connection with the outlet of a blood
dialyzer.
The second chamber communicates with a third port
which in turn is adapted for connection with an arterial
line of the patient. The second chamber also communicates
with a fourth port adapted for connection with an end of
blood pump tubing.
The third chamber communicates with a fifth port
which is adapted for connection with the other end of the
blood pump tubing. The third chamber also communicates
with a sixth port adapted for connection with the inlet
of the blood dialyzer.
In the specific embodiment shown, the flow of
blood enters the second chamber from the artery of the
patient, at which point any bubbles are collected at the
top of the chamber, ~or example, bubbles injected through
an injection site into the line to monitor the flow ve-
locity. The fourth outlet port is generally positioned
at the bottom end of the charnber to facilitate the bubble
trapping characteristic. Bl~od flows out of the fourth
port through pump tubing, which may be installed in a con-
ventional roller pump device to power the flow of blood
through the apparatus.
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Passing through the pump tubing, the blood enters
the fifth port and the third chamber, where an additional
bubble trapping function ta'~es place, to prevent bubbles
from entering the dialyzer. The sixth port exits from the
bottom of the third chamber, and is connected with tubing
which, in turn, leads to the blood inlet of the dialyzer.
Passing through the dialyzer, the blood exits
from the outlet which, in turn, is in connection with the
second port of the first chamber. The blood enters the
first chamber, then generally passing through an air-
blocking filter to prevent infusion of air into the patient.
The blood then passes through the first port of the first
chamber, which is in communication with tubing connected
to the venous system of the patient.
Accordingly, the highly-desirable bubble-trapping
function, plus a blood filtering function, may be provided
by the one-piece hydraulic circuit of this invention.
Additionally, injection-type access sites, for
example, for removal of air, are provided, as well as a
site for measuring chamber pressure. Also, a saline in-
fusion and a heparin line may be added to the device where
desired.
In the drawings, Figure 1 is a perspective view
of the one-piece hydraulic circuit member of this inven-
tion, connected to a hollow fiber-type dialyzer, and
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further connected to auxiliary tubing of various types.
Figure 2 is a transverse sectional view of the
one-piece hydraulic circuit member of this invention,
taken along line 2-2 of Figure 1.
Figure 3 is a similar transverse sectional view
of another embodiment of the hydraulic circuit member of
this invention.
Figure 4 is a detailed sectional view of an
alternative sensing member as a replacement for member
80.
Figure 5 is a sectional view taken along line
5-5 of Figure 1.
Referring to the drawings, hydraulic circuit
member 10 i9 shown to be made of a rigid piece of flat
plastic, defining chambers 12, 14 and 16 within the plas-
tic piece.
As shown in Figure 2, plastic piece 10 may com-
prise a lower flat plastic plate 18 which defines the
chambers and ports utilized herein as cutout portions.
Plastic plate 18 may be sealed by a cover member 20 to
enclose said cutout portions.
Alternatively, as in Figure 3, both plastic plate
18a and cover 20a may be equally-sized pieces, both de-
fining cutout portions for chambers 12, 14, and 16, and
for the various ports.
lla4~ss
Chamber 12 may preferably include a blood filter
member 22, surrounding a first port or conduit 24, which,
in turn, provides communication between chamber 12 and
flexible tubing 26, adapted for communication with the
vein of a patient. In any conventional manner, venous
tubing 26 may contain a sterile injection site 28 for
blood sampling or medication, clamp 30, and removable
sterile cover 32 for sealing the tubing. Tubing 26 may
be connected to a fistula needle for access to the pa-
tient, or an arterio-venous shunt, or any other desired
means for communication with the patient's venous sys-
tem.
Chamber 12 also defines a second port or con-
duit 34 which is shown to define an elongated channel
for communication with a blood outlet conduit 36, re-
ceiving blood from the blood of dialyzer 38. Dialyzer 38
is shown to be a commercially available hollow fiber
dialyzer in this particular embodiment, although this
invention may be used with any type of dialyzer.
Accordingly, blood outflow from the dialyzer 38
enters chamber 12 at an upper end, and passes through
filter 22 into venous line 26 for reinfusion to the pa-
tient.
Second chamber 14 is in communication through
port or conduit 40 with blood tubing 42, which may be
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in communication w~th the arterial system of a patient.
Tubing 42 also may carry a conventional injection site
28, clamp 30, and sterile cover 32, as well as any other
conventional e~uipment. Also, if desired, tubings 26 and
42 may be integrally connected together by a fine web 44
of plastic material, which may be torn apart as far along
the length of the respective tubings 26, 42 as desired,
but otherwise which holds the two tubings together in an
integral manner, to avoid the confusing and inconvenient
separate wandering and coiling of the respective tubes.
Tubes 26 and 42 may be conveniently co-extruded
as a single piece to define the frangible web 44 between
them. Ap~ropriate indicia such as colored lines 46, 48
may be placed on the respective tubing 26, 42 for identi-
fication of the tubing.
Blood from tubing 42 passes through third port
40, preferably at an entry point 50 which is intermediate
along the length of chamber 14, to provide an upper area
52 in the chamber for receiving and retaining gas bubbles.
The blood then is withdrawn from chamber 14
downwardly from the lower end through a fourth port or
conduit ~4 which, in turn, is in communication with a
length of blood pump tubing 56. Tubing 56 may be emplaced
within a roller-type blood pump for movement of the blood
from chamber 14 to chamber 16, and to power the blood flow
. ~
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through the entire system.
If desired, saline solution infusion line 58,
controlled by clamp 60, may communicate in sterile man-
ner with port 54 for use as desired.
The blood from tubing 56 enters fi~th port
or conduit 62, which leads to chamber 16, communicating
- with the chamber at a mid-point thereof in a manner simi-
lar to entry point 50, and for the similar purpose of
providing a bubble-trapping capability to the chamber.
Blood is withdrawn from chamber 16, impelled
by the action of a blood pump on tubing 56, through the
sixth port or conduit 64, which, in turn, communicates
- with an inlet line 66 leading into the blood inlet of
the dialyzer 38.
A hepaxin administration line 70 may be provided
in communication with port 62 if desired, carrying a
sterile end seal 72 for connection with any desired
heparin administration device for administering measured
quantities of heparin over a period of time to the blood
circuit.
Accordingly, blood enters from the patient's
arterial system through tubing 42, passing through port
40 to chamber 14 for bubble removal, and from there to
pump tubing 56 through port 54.
Impelled by the blood pump, the blood is forced
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onwardly through port 62 into chamber 16 for additional
bubble removal, and from there through port 64 into the
dialyzer 38. Dialyzed blood passes along port 34 into
chamber 12. Then, the blood passes through filter 22,
through port 24, and into venous tubing 26 for return to
the patient.
Gripper members 74 are carried by hydraulic
circuit member 10 for grasping, as shown, the dialyzer
38, to provide a convenient, one-piece structure including
both the dialyzer and much of its circuitry. The entire
structure may have a hanger or attachment member (not shown)
for hanging or clamping on an IV pole or the like as de-
sired.
Each of the chambers 12, 14, 16 defines an upper
projecting channel 76. Connected to this channel in
each case is a sealed injection site member 78, which may
include a latex member compression fitted into a tubular
member in a manner similar to the injection site members
which are in present commercial use on the arterial and
venous sets for dialysis sold by the Artificial Organs
division of Travenol Laboratories, Inc., Deerfield,
Illinois. Excess air trapped in the chambers may be
removed by a needle and syrin~ethrough site 78.
Tubing 80 is also in communication with upper
~5 projecting channel 76 in each case. Sealed end 81 may
-- 11 --
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be opened and connected to a manometer or other pressure
measuring device to obtain a direct measurement of the
pressure within chzmbers 12, 14 or 16. Clamp 82 is also
provided to seal tubin~ 80 when not in use. As an al-
ternative structure to replace tube 80 with its direct
connection to each of the chambers 12, 14 or 16, a pressure-
sensing member 84 may be provided which measures the
pressure of the respective chambers in a non-invasive man-
ner.
As shown in Figure 4, pressure-sensing member
84 comprises a housing 86 which fits over an aperture
88 in part of the wall of hydraulic circuit member 10
which is in communication with channel 76. A liquid-
impermeable, flexible diaphragm 90 is positioned across
aperture 88, positioned in the effective sensing range
of a transducer 92, which is adapted to sense the de-
gree of outward or inward bulging of diaphragm 90, in
response to positive or negative pressure in the channel
76.
Accordingly, the pressure within ezch of cham-
bers 12, 14, 16 is reflected by the degree of outward or
inward bulging of diaphragm 90. This, in turn, is sensed
by transducer 92 and communicated along electrical line
94 to a conventional readout device so that, as desired,
the pressure in the respective chambers 12, 14 and 16 can
be monitored, while $he system remains sealed.
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~?4~58
If desired, dialyzer 38 may be made integrally
with hydraulic circuit member 10, in which the fibers and
potting compound conventionally used in fiber dialyzers,
or other membrane material and supports, are placed in
an aperture defined in circuit member 10, to provide the
dialysis function as an integral part of circuit member
10 .
The above has been offered for illustrative
purposes only, and is not for the purpose of limiting the
10 invention of this application, which is as defined in
the claims below.
This application is a division of Canadian patent
Application Serial No. 298,707, filed March 10, 1978.
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