CA1104458A - Integral hydraulic circuit for hemodialysis apparatus - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A one-piece hydraulic circuit is provided for use with a blood dialyzer for performing functions cur-rently performed with a multiplicity of blood inlet and outlet sets and related items comprising flexible tubing and the like.

Description

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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 ~U4~S~

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 11~4~

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 4~8 -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 . ~

~1~44~;8 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 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 ~a~s~

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.

~?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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Claims (15)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a hydraulic circuit member for use with a membrane diffusion device, which comprises a unitary member defining a plurality of blood-receiving chambers, and conduit means com-municating between said blood-receiving chambers, for directing, receiving, and processing blood passing through said membrane diffusion device, in which at least one of said blood receiving chambers defines a transversely-enlarged upper chamber portion connected by a step wall which abruptly narrows the bottom end of said enlarged chamber area to a lower chamber portion of lesser transverse dimension, and points of communication of said conduit means with said chamber, including 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 said lower portion remote from said enlarged upper portion of said chamber, said chamber defining vent means for gases at its upper end and constituting an improved bubble trap for blood when blood is introduced through said inlet and withdrawn through said outlet.

2. The hydraulic circuit member of claim 1 in which said circuit member comprises a rigid, unitary member made of a flat plastic plate having chambers and ports defined by cut-out portions in said flat, plastic plate, and said plas-tic plate is sealed by a cover member to enclose said cut-out portions.

3. A one-piece hydraulic circuit member for use with a blood diaiyzer for directing and controlling blood flow which comprises, a rigid, unitary member defining spaced chambers for receiving blood, and conduit means communicating with said chambers adapted respectively for connection with a venous line of a patient, the blood inlet and outlet of a blood dialyzer, an arterial line for the patient, and ports for communication with blood pump tubing, in which at least some of the chambers de-fined within said rigid unitary member constitute blood-receiving chambers defining a distinct, enlarged chamber area at an upper portion thereof connected by a step wall to a lower portion thereof which is not transversely enlarged, and points of com-munication of said conduit means with said chamber including a first point of communication spaced from the bottom of said chamber and communicating directly with said distinct enlarged chamber area in an upwardly-pointing direction through said step wall, and a second point of communication of said conduit means with said chamber being positioned adjacent the end of said lower portion remote from the upper portion of said chamber, and venting means provided at the top of said chamber, whereby improved bubble-trapping capabilities are provided to blood in said chamber which is introduced to the chamber through said first point of communication and withdrawn through said second point of communication.

4. In a hydraulic circuit member for use with a membrane diffusion device, which comprises a unitary, rigid, flat plas-tic member defining a plurality of blood-receiving chambers, conduit means for communicating between said blood-receiving chambers, said membrane diffusion device, and the arterial and venous lines of a patient, in which at least one of said blood receiving chambers defines an aperture, said aperture being sealed by a liquid-impermeable, flexible diaphragm, and pressure sensing means adjacent said diaphragm outside of said chamber, whereby displacement of said diaphragm in response to pressure in said chamber is sensed by said pressure sensing means, said chamber defining a distinct, enlarged chamber area at an upper portion thereof with respect to the lower portion, said enlarged chamber area being separated from the lower portion by a step wall abruptly narrowing the lower end of said enlarged chamber area, and communication apertures of said conduit means with said chamber including a first aperture spaced from the bottom of said chamber and communicating directly with said enlarged chamber area in an upwardly-pointing direction through said step wall, and a second aperture of said conduit means being positioned adjacent the end of said lower portion, remote from the upper portion of said chamber, said chamber defining gas vent means adjacent its upper end, whereby blood entering said chamber through said first aperture is subjected to improved bubble-trapping action, and blood may be withdrawn from said second aperture.

5. A hydraulic circuit member for use with a blood dialyzer in which first, second and third chambers are present in said unitary, rigid member, at least one of which is of the shape as defined in claim 5 and further including a first port, communicating with said first chamber and adapted for connection with a venous line of a patient, and a second port communicating with said first chamber and adapted for connection with the out-let of a blood dialyzer; a second chamber communicating with a third port, said third port being adapted for connection with an arterial line of a patient, said second chamber also communicating with a fourth port adapted for connection with blood pump tubing, and a third chamber communicating with a fifth port adapted for connection with said blood pump tubing, said third chamber also communicating with a sixth port adapted for con-nection with the inlet of said blood dialyzer.

6. The hydraulic circuit member of claim 5 in which said first chamber contains a blood filter positioned for filtering gases from the blood flow through said first port.

7. The one-piece hydraulic circuit member of claim 5 in which said chambers and ports are defined by cut-out portions in a flat plastic plate, said plastic plate being sealed by a cover member to enclose said cut-out portions.

8. The one-piece hydraulic circuit member of claim 5 in which a saline infusion line is in communcation with said port.

9. The hydraulic circuit member of claim 5 in which a heparin line is in communication with said fifth port.

10. The hydraulic circuit member of claim 5 in which a sealable injection site provides communication by means of an injection needle to said chambers.

11. The hydraulic circuit member of claim 5 which defines means for carrying a dialyzer for blood.

12. The hydraulic circuit member of claim 11 in which said first port is connected to a venous line and said third port is connected to an arterial line, said arterial and venous lines being joined together along one side along a major portion of their lengths.

13. The hydraulic circuit member of claim 12 in which said third and fifth ports respectively communicate with said first apertures in said second and third chambers while said fourth and sixth ports communicate respectively with said second and third chambers at said second apertures.

14. The hydraulic circuit member of claim 13 in which said first port communicates with the lower end of said first chamber and said second port communicates adjacent the upper end of said first chamber.

15. A blood receiving chamber for use in blood handling equipment having conduit means communicating with said blood receiving chamber, the improvement comprising: said blood-receiving chamber defining a distinct, enlarged chamber area at an upper portion thereof with respect to a lower portion, and inlet conduit means communicating directly with said dis-tinct, enlarged chamber area in an upwardly pointing direction, the point of communication of said conduit means being spaced from the ends of said chamber, and a second outlet point of communication between said conduit means and chamber adjacent the bottom thereof, said chamber defining vent means for gases at its upper end.