GB2047542A - Bubble trap - Google Patents

Abstract

The bubble trap comprises an elongate member 14 having flexible walls and depending vertically from a horizontal rigid bracket 10. The member defines a chamber having an upper portion of greater transverse dimensions than a lower portion and between the portions an intermediate horizontal wall portion 88 is provided with an inlet conduit 86. An outlet conduit leads from the lower portion of the chamber either from a port in the lower portion (on the left side of Fig. 3) or by extending downwardly into the chamber (as conduit 70 on the right side of Fig. 3). <IMAGE>

Description

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GB2 047 542A

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SPECIFICATION Bubble trap

5 This invention is concerned with bubble traps for use in medical equipment e.g. for removing bubbles from blood.

The bubble trap of the invention is especially useful for use in a medical set for use 10 with a diffusion device, such as a dialyzer, for removing bubbles from blood or from dialysis solution. Our U.K. patent specification No. 2021418 describes and claims such a medical set including the bubble trap of the pre-1 5 sent invention.

The present invention provides a bubble trap for a medical fluid flow line which comprises a flexible-walled chamber-defining member depending, in the position of use, 20 from a horizontally disposed, generally rigid upper supporting wall which carries said member, an upper portion of said chamber, adjacent said supporting wall, having a larger transverse dimension than a lower portion of 25 said chamber remote from said supporting wall, an intermediate wall portion of the member, between said upper and lower chamber portions, extending transversely, a first access port communicating between the exterior and 30 a position in said chamber adjacent the intermediate wall portion, and a second access port communicating between the exterior and a position adjacent the lower end of the chamber remote from said upper supporting 35 wall.

This type of bubble trap exhibits numerous advantages. Its flexibility allows it to be squeezed in the manner of a conventional drip chamber to aid in the priming of the set. Also, 40 the first access port, which preferably passes through the intermediate wall, is particularly advantageous for the removal of bubbles, because it may enter below the liquid level (the liquid level being normally at a position in the 45 upper chamber) in such a manner that the bubbles have an upward velocity component to assist in their separation from the blood, However, foaming is reduced when the entry is substantially at a sub-liquid level. Accord-50 ingly, the upwardly moving bubbles are urged to the top of the chamber immediately, where they tend to join the bubble which is normally present at the top of the chamber interior during operation.

55 Similarly, the relatively enlarged upper portion of the bubble trap provides added volume, with a consequent reduction of major liquid level changes with minor changes of blood volume in the bubble trap. Also, the 60 larger, upper portion of the bubble trap results in a lower velocity of the blood at the top of the trap, permitting removal of the last numbers of microbubbles.

The second access port of the bubble trap 65 may be a tube passing through the bracket member and terminating adjacent the lower chamber end, or may be a conduit passing through the chamber-defining wall adjacent the lower chamber end. In both of these 70 instances, these ports define the exit from the bubble trap and are at its lowest level, remote from any bubbles which may remain in the system.

In the drawings,

75 Figure 7 is a perspective view of one embodiment of the medical set of this invention, adapted for use in conjunction with a hollow fibre-type dialyzer for blood, with the rigid interior access members having been broken 80 away out of their initial position of integral connection with the bracket member, and other parts also removed from their initial configuration to a ready-to use configuration.

Figure 2 is a plan view of the bracket 85 member and related parts of this invention, with the dialyzer and some other parts not shown for purposes of clarity, showing the interior access members in their as-moulded, integrally connected relation to the bracket 90 member.

Figure 3 is an elevational view, with some parts shown in section, of the bracket member of this invention, showing as in Fig. 2, the interior access members in their initial, inte-95 grally-attached relation with the bracket member.

Figure 4 is a fragmentary plan view of another embodiment of the medical set of this invention in which the access members are 100 removably attached to the bracket member by means of clips.

Figure 5 is an elevational view, taken partly in vertical section, showing portions of the embodiment of Fig. 4.

105 Figure 6 is a perspective view showing how individual generally rigid interior access members adapted to be carried in the clip of the embodiment of Figs. 4 and 5 may be all integrally moulded together in a family mould. 110 Referring to Figs. 1 through 3, the medical set shown therein defines a bracket member 10 adapted to carry in sealed, depending, hanging relation thereto, a pair of flexible bubble traps 12, 14 and other flexible flow 115 lines for fluid to be described later.

In this embodiment, bracket 10 defines a clamp member 16, which is a section of a cylinder more than 1 80° in arc, which may attach in snap-fit relationship to a conven-120 tional hollow fibre dialyzer 18.

As is typical, dialyzer 1 8 defines dialysis solution ports 20, and blood inlet 22 and outlet 24, so that the blood may enter into dialysis exchange relationship with the dialysis 125 solution across a membranous barrier provided by the hollow fibres in dialyzer 18. Holding bracket 26 is provided having fingers 28 which fit around the cylindrical section 16 to carry both the set of this invention and 130 dialyzer 18, as shown in Fig. 1. Fingers 28 fit

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around retaining stud 29.

As previously described, various interior access members are initially integrally attached to bracket member 10, having typically been 5 moulded in the same operation as the bracket 10, which may be typically made of a thermoplastic material. As shown in Figs. 2 and 3, connectors 30, 32 which serve to connect to cannulas, which, in turn, connect to the pa-10 tient's blood system, intially constitute an integral part of bracket member 10 by means of moulded webs 34, which may be manually broken away to separate connectors 30, 32 when desired for use as in Fig. 1. 15 Similarly, T-connectors 36, 38 which are positioned intermediately along a length of flow line is described below, may be integrally moulded with and connected to bracket member 10 by means of frangible webs 40, as 20 shown in Figs. 2 and 3. These also may be separated by manual breaking of webs 40 as in Fig. 1.

The above arrangement greatly simplifies the manufacture of parts for the set. For 25 example, in this particular embodiment, five separate parts are simultaneously moulded in the moulding of the bracket member. It is further contemplated that yet more parts may be simultaneously moulded in similar manner, 30 if desired.

After the moulding step, the flexible tubings and the like may be attached to the various rigid, simultaneously-moulded parts as desired.

35 Further describing the set of this invention, arterial line 42 comprises flexible tubing which may be made of poly-vinyl chloride or other flexible, blood-compatible material and typically having an inner diameter of 0.187 40 inch and a wall thickness of 0.045 inch. As seen in Fig. 1, arterial line 42 terminates in a connection with connector 30 which is used to make connection with a cannula which communicates with the arterial system of a 45 patient in conventional manner. Flexible, attached cap 44 seals connector 46 until it is desired to open it. On/off clamp 46 is provided to shut off the flow through arterial line 42 when necessary.

50 Intermediately positioned on arterial line 42 is injection site 48, which in this particular embodiment is not initially integrally attached to bracket member 10. However, such attachment is contemplated as a possibility in other 55 embodiments. Injection site 48 is similar to injection sites which are currently found on conventional arterial and venous sets, sold by Travenol Laboratories of Deerfield, Illinois. Alternatively, an injection site similar to U.S. 60 Patent No. 3,850,202 may be used, if desired.

As blood flows from the patient's arterial system through connector 30 and injection site 48, it passes through another length of 65 arterial line 42, and then through a stepped and branched connector 36, which provides connection with a fluid addition line 52,

which is particularly used for the addition of saline for priming the set and at other times 70 as desired. Connector 36 is initially attached to the bracket member 10 as shown in Fig. 2, and then is broken off for use, as described above.

Downstream from connector 36 is a length 75 (typically about 18 inches) of roller pump tubing 50, which is generally of greater diameter than arterial tubing 42. necessitating the use of the stepped connector 36, in which bore 52 has a tapered portion and differently-80 sized lengths as shown in Fig. 1. Tubing 50 may have an inner diameter of 0.250 inch and a wall thickness of 0.060 inch.

At the other end of roller pump tubing 50 is a second stepped and branched connector 38 85 which is also initially attached to the bracket member 10. Connector 36 provides a branched connection for a heparin line 56 which may be initially coiled, and is terminated by a cap 58 which may normally fit into 90 apertured flap 60, which flap may be an integrally moulded part of stepped connector 38. Thus, cap 58 is retained in the apertured flap 60 to retain line 56 in an orderly manner.

Full tab 62 on cap 58 facilitates the re-95 moval of the cap from flap 60 when the heparin line is desired to be used, being connected to a conventional heparin administration device for blood.

Downstream of connector 38 is a final 100 length of arterial tubing 42, which communicates at its end through an intermediate wall 64 of flexible bubble trap 12, which serves to seal the portion of upper, enlarged chamber 66 where it extends beyond the lower, narrow 105 chamber 68 of the bubble trap. Any bubbles which are present are forced upwardly into enlarged chamber 66 through the intermediate wall 64. which facilitates the separation of the bubbles without foaming when the blood 110 surface level 69 is positioned in enlarged chamber 66.

Following this, the blood passes upwardly from the bottom of narrow chamber 68 through depending tube 70, passing upwardly 115 through bracket member 10 into inlet line 72, which may also be a flexible tube made out of polyvinyl chloride or the like. Line 72 communicates with the blood inlet 22 of dialyzer 18.

Another sterile injection site 74 is provided 120 through bracket member 10, for communication by means of a needle into enlarged chamber 66 for sampling and for removal of air bubbles and the like. Injection site 74 is of conventional design.

125 Arterial monitor line 76 also has an end 78 communicating through bracket member 10 into bubble trap 12 to permit the measurement of the bubble trap pressure, The opposite end of line 76 terminates in a conven-130 tional connector member 80, which may fit in

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aperture 82 of bracket member 10. Slot 84 is also provided in bracket member 10 to serve as an on/off clamp for arterial pressure monitor line 76. Jaws 85 serve to receive and hold 5 a coil of line 76 during storage to reduce the kinking.

Dialyzed blood which passes from outlet 24 enters flexible conduit 86, which in turn, communicates at its other end with a conduit 10 passing through the intermediate wall 88 of bubble trap 14, which corresponds to intermediate wall 64 of bubble trap 12. In the same manner, bubbles are urged upwardly by the upward entry of blood, and foaming is 1 5 minimized by maintaining the blood level in the enlarged chamber 90 of bubble trap 14, which corresponds to enlarged chamber 66 of trap 12. Blood is withdrawn from narrow chamber 92 of bubble trap 14, which corre-20 sponds to chamber 68 in trap 12, passing through a sock-type filter 94 and entering venous line 96, which is attached to a conduit which passes through the bottom of bubble trap 14. Venous line 96 may also be made 25 out of the same conventional, flexible, blood-compatible plastic as before.

Another injection site 98, similar to site 74, extends through bracket member 10 for sampling, and particularly to permit removal of 30 gas bubbles from bubble trap 14 in an aseptic manner.

Venous bubble trap pressure monitor 100 communicates at one end 102 through bracket member 10 with the interior of bubble 35 trap 14, and terminates at its other end in a conventional connector 106. Connector member 106 may be stored until used in aperture 108 (Fig. 2) in bracket member. Also, slot 110 is provided to serve as an on/off clamp 40 for the venous pressure line. Jaws 111 serve to hold a coil of tube 100 in the manner of jaws 85.

As the dialyzed blood passes through venous line 96, it encounters injection site 112, 45 which is similar in construction to injection site 48 on the arterial line. Clamp 114 is also provided to shut off flow through the system when desired.

Finally, venous line terminates in connector 50 32, having sealing cap 114, which is adapted to be connected with a cannula for communication with the venous system of the patient in conventional manner. Connector 32 is the fourth access member in this present embodi-55 ment which originally was integrally attached to bracket member 10.

If desired, sections of the flow lines, for example lines 42 and 96, may be co-extruded on a side by side basis, being joined together 60 by only a thin web of material so that the tubings may be manually pulled apart as desired and when needed. This simplifies the arrangement of the system, and reduces a possible confusing, tangled snarl of tubing 65 during use.

Referring to Figs. 4 and 5, there is shown an alternative integral medical set of this invention which is identical in structure, purpose, and function to the embodiment of Figs. 70 1 and 3, except as otherwise indicated below.

Bracket member 10a may be integrally molded as in the previous embodiment, including clamp member 16a for retention in snap-fit relationship to a conventional hollow 75 fibre dialyzer.

As a chief difference from the previous embodiment, bracket member 10a carries a series of integrally molded gripping means or clamp members 120, 122, 124, and 126, 80 which comprise cylindrical sections integrally attached and part of the molded bracket member 10a, for the purpose of removably retaining by spring-gripping action the various interior access members including connectors 30a, 85 32a and T-connectors 36a, 38a which correspond in function to the parts of the same number in the previous embodiment.

As further distinction from the previous embodiment, the positioning of clamp members 90 120, 122, 124 and 126 has been changed to the front of bracket member 10a from the corresponding positions shown in the previous embodiment, with members 36a and 38a being on opposite sides from the correspond-95 ing parts in the previous embodiment.

Since interior access members 30a, 32a, 36a, 38a are not integral with bracket member 10a, but are still removably attachable thereto, the respective parts may be made in 100 a single, separate, family mold operation to provide a product as shown in Fig. 6. There, the respective integral access members are all connected together by means of a conventional family mold web 128.

105 After the molding, the respective parts may be broken away from web 128, attached to their respective connected tubing members as in the previous embodiment, and snapped into the clamp members 120, 122, 124, 110 126.

Caps 1 29, 1 30 of members 30a and 32a may be integrally molded as shown, being connected by thin, flexible webs 1 32, or they may alteratively be separately molded and 11 5 attached with a loop about the circumference of the integral access members.

The remaining parts of the embodiment of Figs. 4 and 5 may be identical in structure and function to the previously described parts 1 20 of the same number in the previous embodiment of Figs. 1 through 3.

In particular, tubing 56a may be attached after molding of the connectors to connector 38a, while tubing 52a may be attached to 125 connector 36a, to provide the functions as described previously for tubings 52 and 56. Tubings 42a and 50a may be similarly attached to provide the same functions as described previously.

1 30 One particular advantage of the embodi

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ment of Figs. 4 and 5 is that the bracket 10a of this invention can be used in conjunction with separately-made blood tubing sets, such as arterial and venous sets for artificial kid-5 neys, or corresponding sets for oxygenation. Thus, stock sets of different types as desired may be attached to the separate bracket 10a at a time prior to use, and the composite system may be sterilized and prepared for 10 service at a later time, for example, in emergency situations. Bracket member 10a serves to hold the arrangement in an orderly manner and carries the bubble traps and other items, so that final setup is accomplished more 1 5 quickly and with less possibility of error or break of sterility.

The above sets provide a substantial improvement in convenience of use and reliability, since they can be pre-assembled and 20 sterilized at the factory under closely controlled conditions, rather than being assembled out of component parts at the various places of use by personnel who may be overworked or inadequately trained. 25 Also, a substantial cost saving is realized by the simultaneous molding of various parts for the set of this invention, and the same arrangement provides a convenient, compact storage of the set in an orderly regular form.

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Claims (6)

1. A bubble trap for a medical fluid flow line which comprises a flexible-walled chamber-defining member depending, in the posi-

35 tion of use, from a horizontally disposed, generally rigid upper supporting wall which carries said member, an upper portion of said chamber, adjacent said supporting wall, having a larger transverse dimension than a lower 40 portion of said chamber remote from said supporting wall, an intermediate wall portion of the member, between said upper and lower chamber portions, extending transversely, a first access port communicating between the 45 exterior and a position in said chamber adjacent the intermediate wall portion, and a second access port communicating between the exterior and a position adjacent the lower end of the chamber remote from said upper 50 supporting wall.

2. The bubble trap of Claim 1 in which said second access port comprises a tube passing through said upper supporting wall and terminating adjacent said lower end of

55 the chamber.

3. The bubble trap of Claim 1 in which said second access port comprises a conduit passing through the flexible chamber-defining wall adjacent said lower end of the chamber.

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4. The bubble trap of Claim 3 in which a filter is positioned adjacent said lower end of the chamber.

5. The bubble trap of any preceding Claim in which said first access port comprises a 65 conduit passing through said intermediate wall portion.

6. A bubble trap constructed substantially as herein described with reference to the accompanying drawings.

Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon) Ltd.—1980.

Published at The Patent Office, 25 Southampton Buildings,

London, WC2A 1AY, from which copies may be obtained.