US3578411A

US3578411A - Bubbler assembly for blood treating apparatus

Info

Publication number: US3578411A
Application number: US843558A
Authority: US
Inventors: Donald J Bentley; Richard A De Wall
Original assignee: Bentley Laboratories Inc
Current assignee: Baxter International Inc; Bentley Laboratories Inc
Priority date: 1969-07-22
Filing date: 1969-07-22
Publication date: 1971-05-11
Anticipated expiration: 1988-05-11
Also published as: JPS4944758B1; DE2036424A1; FR2053069B1; GB1304906A; FR2053069A1

Abstract

A BUBBLER ASSEMBLY FOR USE IN A BLOOD TREATING APPARATUS SUCH AS A BLOOD OXYGENATOR FOR FORMING FILMS OF BLOOD IN BUBBLE FORM BY DIRECTING OXYGEN INTO A STREAM OF VENOUS BLOOD TO EFFECTUATE TRANSFER OF OXYGEN TO THE BLOOD FILM AND RELEASE OF CARBON DIOXIDE FROM THE BLOOD FILM. THE BUBBLER ASSEMBLY IS CHARACTERIZED BY AN IMPROVED ARRANGEMENT OF THE BLOOD PASSAGEWAY WHICH IS GENERALLY S-SHAPED IN NATURE; BY A COMPLETELY SMOOTH INTERIOR WHICH ELIMINATES SHARP EDGES; BY AN IMPROVED OUTLET STRUCTURE WHEREBY BLOOD BUBBLES EMPTY OUTWARDLY AND DOWNWARDLY ON A DEFLECTOR PLATE FOR MORE UNIFORM DISTRIBUTION OF BLOOD THROUGH AN ENVELOPING DEFOAMER UNIT; AND BY AN IMPROVED EXTERIOR CONFIGURATION HAVING RECESSED SIDE PORTIONS RELATIVE TO ADJACENT TOP AND BOTTOM STRUCTURE BY MEANS OF WHICH A GREATER PORTION OF THE DEFOAMER SLEEVE IS HELD RELATIVELY SPACED FROM THE BUBBLER STRUCTURE TO ELIMINATE OBSTRUCTIONS TO THE FLOW OF BUBBLES PASSING OUT OF THE BUBBLER UNIT AND TO EXPOSE A GREATER AREA OF THE DEFOAMER SLEEVE TO THE BLOOD.

Description

BUBBLER ASSEMBLY FOR BLOOD TREATING APPARATUS Filed July 22, 1969 y 1.971 0. J. BENTLEY ETAL 3 Sheets-Sheet 1 //VVEA/ 7'0?! pwmddgzxz ZMm/daa? Z/QZZ 15) Wu 1 44., 9 TOP/V573 BUBBLER ASSEMBLY FOR BLOOD TREATING APPARATUS Filed July 22, 1969 D. J. BENTLEY ET AL 3 Sheets-Sheet 2 3 sheets sheet 3 BUBBLER ASSEMBLY FOR BLOOD TREATING APIARATUS & WW MW Q 5 \ww MW, n uhw Bm k v m g W\ i May 11, i971 Filed July .212; 1969 United States Patent O 3,578,411 BUBBLER ASSEMBLY FOR BLOOD TREATING APPARATUS Donald J. Bentley, Newport Beach, Calif., and Richard A.

De Wall, Dayton, Ohio; said De Wall assignor to Bentley Laboratories, Inc., Santa Ana, Calif.

Filed July 22, 1969, Ser. No. 843,558 Int. Cl. A61m N03 US. Cl. 23-2585 11 Claims ABSTRACT OF THE DISCLOSURE A bubbler assembly for use in a blood treating apparatus such as a blood oxygenator for forming films of blood in bubble form by directing oxygen into a stream of venous blood to effectuate transfer of oxygen to the blood film and release of carbon dioxide from the blood film. The bubbler assembly is characterized by an improved arrangement of the blood passageway which is generally S-shaped in nature; by a completely smooth interior which eliminates sharp edges; by an improved outlet structure whereby blood bubbles empty outwardly and downwardly on a deflector plate for more uniform distribution of blood through an enveloping defoamer unit; and by an improved exterior configuration having recessed side portions relative to adjacent top and bottom structure by means of which a greater portion of the defoamer sleeve is held relatively spaced from the bubbler structure to eliminate obstructions to the flow of bubbles passing out of the bubbler unit and to expose a greater area of the defoamer sleeve to the blood.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to blood treating apparatuses and, more particularly, to a bubbler assembly preferably for use with a blood oxygenator.

Brief description of the prior art The present invention is an improvement in the bubbler assembly shown in the copending application of Bentley and De Wall entitled Bubbler Assembly for Oxygenator, Ser. No. 601,000 (Series of 1960) filed Dec. 12, 1966. Application Ser. No. 601,000 was an improvement upon the bubbler assemblies shown in the Richard A. De Wall Patent No. 3,256,883, issued June 21, 1966 and the presently copending application of Donald A. Raible, Donald 1. Bentley and Richard A. De Wall, Ser. No. 465,451, filed June 21, 1965, Bentley and De Wall application 601,000 has now issued as US. Patent No. 3,488,158, and Raible et al., application 465,451 has issued as U.S. Patent No. 3,468,631.

.Prior art cited in the aforementioned Bentley and De Wall application Ser. No. 601,000 includes the following patents, all from Class 23, Subclass 258.5: Calvin, 293,067; Broman, 3,058,464; De Wall, 3,253,883; Sautter,

All of these patents are directed to oxygenators in their entirety. In all of these patents, the bubbler portion of the oxygenator is generally a straight tube with a regular exterior periphery. The blood outlet is merely the distal open end of the tube except in the De Wall Pat. 3,253,883, where the outlet comprises plural ports in the wall of the tube with the distal end of the tube wall being closed. In the blood treatment art there is a continuing need and desire for thorough intermixing of blood and oxygen, thorough debubbling of oxygenated blood and thorough filtering of particles from the blood including the elimination of any accumulated blood fragments. Thorough in- "ice ter-mixing of blood bubbles in a bubbler assembly is promoted by avoiding stratification of the blood bubbles. Thorough debubbling and defoaming is promoted by spreading the emitted blood bubbles so as to expose the blood bubbles to a wide area of defoaming material in a smooth and continuous flow. Improved filtering is also accomplished by exposing the blood to a greater surface area of the defoaming material. The elimination of blood fibrin and of damage to hemoglobin is promoted by having the blood passageway of a smooth structure free of crevices and sharp edges or extremely sharp corners.

It is to the provision of these enumerated desired properties and for the purpose of meeting the above stated need and desire in the art that the present invention is directed.

SUMMARY OF THE INVENTION The present invention is directed, in brief, to the provision of an improved bubbler assembly for a blood treating apparatus, such as a blood oxygenator.

The best mode currently contemplated by us for carrying out the invention includes the provision of a one piece plastic molded structure having an inlet, three chambers arranged in vertical tandem and in communication with each other in ascending order, and an outlet at the end of the uppermost chamber remote from the inlet end. Generally speaking, in the preferred form the chambers are disposed in a generally 'S-shaped array. The structure is preferably formed of a polycarbonate plastic, and it is formed into an integral, single piece by a blow molding process which results in savings in manufacture over methods which adhere a plurality of pieces together.

The interior of the blood passageways defined by the communicating chambers is free of sharp corners or sharp or raw edges. The blood outlet is shaped to direct blood downwardly onto an inclined deflector plate which is the upper surface of the intermediate blood chamber at the juncture with the lowest chamber. The sides of the intermediate chamber are recessed relative to the upper and lower chambers. By this arrangement, the enveloping defoamer sleeve is held spaced from the intermediate portion of the bubbler to minimize obstructions for the emitted bubbles and to afford utilization of a greater portion of the surface area of the defoamer sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of an oxygenator device of the type in which the bubbler assembly of the instant invention is intended to be used;

FIG. 2 is an enlarged fragmentary sectional view of the oxygenating chamber of the oxygenator device shown in FIG. 1 showing the bubbler assembly of this invention in greater detail;

FIG. 3 is a sectional view of the bubbler assembly shown apart from its intended environmental use in the oxygenator chamber;

FIG. 4 is a vertical sectional view of the bubbler assembly taken generally along the lines 44 of FIG. 3; and

FIG. 5 is a fragmentary sectional view taken generally along the lines 5--5 of FIG. 3.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a bubble type oxygenator device 10 with which the bubbler assembly of this invention is intended to be used. As shown, the oxygenator device includes an upper cylindrical chamber 12 (commonly referred to as the oxygenating chamber), a narrow central chamber 13 (commonly referred to as a settling chamber) and a lower cylindrical chamber 14 (commonly referred to as a heat exchange chamber) and a collecting chamber 18 below the heat exchange chamber. In use, the oxygenator device is preferably suspended by hooks or other suitable means passing through the apertures 20 at opposite ends of the chambers so that in normal operation the angle of the axis of the upper cylindrical chamber relative to the horizontal is preferably in the range of 35 to 50.

The bubbler assembly 22 of this invention is intended for use in the upper or oxygenating chamber 12 of the oxygenator 10. It is to be understood that the bubbler assembly 22 may have suitable use with other blood treating apparatuses and that the showing of the bubbler assembly with the oxygenator is only for the purposes of illustrating one preferred form of use of the bubbler assembly. In use with the oxygenator 10, the bubbler assembly is preferably mounted so that its longitudinal axis substantially coincides with the longitudinal axis of the oxygenating chamber 12.

Generally speaking, the function of the bubbler as sembly is to intermix oxygen gas with incoming venous blood so as to form films of blood in bubble form, which blood bubbles are advanced in an oxygen atmosphere through the bubbler assembly through an outlet or a plurality of outlets. Thus, in the bubbler assembly oxygen is taken on by the venous blood and carbon dioxide carried by such blood is released. The degree to which the blood is saturated with the oxygen depends significantly upon the extent to which all of the blood is bubbled, the character of the film in the bubbles produced, the time of exposure of the blood film to the oxygen atmosphere. Preferably the bubbler assembly (as well as the oxygenator) is formed from a polycarbonate plastic (sold by General Electric under the trademark Lexan). This plastic has been found to be very suitable for use in blood treating apparatuses in that it is inert, nontoxic, impervious to the passage of gases and liquids, and sterilizable. It further contains no leachable plasticizers which may be traumatic to the blood, and is exceptionally strong and durable to withstand accidental blows or shocks. In addition it has a natural electrical surface charge similar in nature to the natural charge of the constituents of the blood. It is to be understood that while this material has been found preferable for use, any other material which meets the same advantageous standards mentioned herein could also be suitably used.

The bubbler assembly 22 is defined by a substantially hollow, elongated housing, generally designated 24, which defines an internal chamber, generally designated 26. One end of the chamber is provided with a generally cylindrical opening 28 which provides an inlet means for admission of fluids such as oxygen or venous blood.

In one preferred form of use of the bubbler assembly, the open end 28 nestably receives an inwardly extending boss portion 30 of the end wall assembly 32 which encloses the forward portion of the oxygenator chamber 12. Boss 30 includes a generally frusto-conically shaped Wall member 34 which extends from an inlet aperture '36 and flares outwardly to the interior of the bubbler assembly. Preferably, at least a portion of the wall member 34 is provided with a plurality of small openings or apertures 38 for a purpose to be explained.

A fluid inlet fitting 40 is nested within boss 30 and about inlet aperture 36. Inlet fitting 40 includes an oxygen inlet fitting 42 for directing oxygen into the interior of the bubbler assembly through the openings 38 in the frustoconical wall; and a blood inlet fitting 44 for directing blood into the interior of the bubbler assembly through the inlet 36 at the reduced end of the frustoconical wall.

The housing 24 and its internal chambers 26 define a continuous closed passageway leading from the inlet end 28 to an outlet means or opening 46 which is remote from the inlet. As mentioned, a thorough intermixing of blood bubbles is most desirable to promote optimum oxygen carbon dioxide exchange. The bubbler assembly of this invention is ideally suited for promoting this 4 thorough intermixing and preventing stratification of the blood bubbles during passage through the bubbler assembly.

The housing 24 is partitioned so that its internal chamber 26 is divided into a plurality of chamber segments. A lower chamber segment 48 is defined by a generally rounded bottom wall 50 and a generally planar top wall 52 and extends from the inlet 30 downwardly and rearwardly away therefrom to an upwardly returned rounded end portion 55. The interior surface 55a of portion 55 directs fluid upwardly through juncture portion 56 by means of which lower chamber segment 48 is in com munication with a vertically adjacent central or intermediate chamber segment 54. Fluid is further directed upwardly and forwardly by the interior surface 57a of inclined wall portion 57. The exterior surface 57b provides a blood spreading surface as will be explained later.

Intermediate chamber segment 54 is defined by a generally planar lower wall 58 connected by web 58a to wall 52 and a generally planar upper wall 60. Inclined wall portion 57 generally spans wall 60 and rounded end portion 55. A rounded portion 61 of very short radius joins

walls

52 and 58. Chamber 54 extends from its juncture 56 at the rear in communication with lower segment 44 to a forward position where it joins with upper chamber segment 62. The interior surface 63a of upwardly inclined wall portion 63 directs fluid through juncture portion 64 by means of which chamber segment 54 communicates with chamber segment 62. Fluid is returned rearwardly of chamber segment 62 by the interior surface 65a of rounded rearwardly returned wall portion 65. Upper chamber segment 62 leads away from its juncture at 64 with central chamber segment 54 to a rounded end portion 66 and terminates in an opening 46 remote from the inlet 28. End portion 66 is downwardly returned relative to the remainder of segment 62 and the interior surface 66a thereof provides a deflecting portion adjacent to outlet means 42 for directing blood toward lower segment 48 and particularly to surface 57b of inclined wall 57. Upper chamber segment 62 is further defined by a generally planar bottom wall 68 and a generally rounded top wall 70. Bottom wall 68 is joined to wall 60 by web 68a and rounded portion 71 of very short radius.

Thus, blood entering generally through the inlet area 28 will travel an inverted S-shaped path first passing through the lower segment 48, thence being directed upwardly and returned forwardly through the central segment 54 and thence being directed upwardly and returned rearwardly through the upper segment 62 from which it is passed outwardly through outlet 46. At each bend in the chamber, blood bubbles will meet generally rounded surfaces and be intermixed. For example, at each of juncture portions 56 and 64, blood bubbles which were travelling near the top of the previous chamber segment Will intermix with blood bubbles that were travelling near the bottom as the blood is directed upwardly and returned in a relatively opposite direction of travel. By travelling in this continuous convoluted path, intermixing of the blood is promoted and Stratification thereof is substantially eliminated.

The lateral extent of lower segment 48 and upper segment 62 is defined by the rounded side edges 72 and 74 of

lower segment

48 and 76 and 78 of upper segment 62. The lateral extent of the central segment 54 is defined by the generally

planar sides

80 and 82. As can be seen best in FIG. 4, sides 80 and 82 are recessed inwardly relative to

side portions

72, 74 and 76,78. Generally speaking, this provides a longitudinally extending recess intermediate of the top and bottom of the housing 24 on either side thereof. When the bubbler 22 is assembled in the oxygenating chamber 12, it is surrounded by a defoaming sleeve generally indicated as 84. Typically, the defoaming sleeve includes a polypropylene mesh fiber 86 inside of a nylon mesh bag 88. The fiber tends to generally intimately follow the exterior contour of the bubbler 22. It has been found that if the sleeve is too tightly about the exterior of the bubbler, it tends to form an obstruction to the flow of bubbles passing out of the bubbler unit.

With the bubbler of the present invention, the overhang of

sides

72, 74 and 76, 78 relative to the

intermediate sides

80, 82 tends to hold the sleeve 84 spaced outwardly from the intermediate portion of the bubbler assembly as represented by the dotted

lines

90 and 92 in FIG. 4. This relationship between the side walls and the sleeve extends throughout most of the length of the bubbler and thus, there is free space for blood to flow a substantial distance along the length of the side of the bubbler to insure the free flow of blood and bubbles outwardly of the bubbler and the passage of blood through the defoaming sleeve 84. Further blood passageways are afforded by the spaces 94-96 and 98-100 between walls 68 and 60 on each side of web 68a and between

walls

58 and 52 on each side of web 58a, respectively.

Another feature of the bubbler assembly of the instant invention is the structure of the outlet 46 and the adjacent spreader plate 57b therebelow. As best seen in FIG. 5, the opening 46 is a large generally rectangular opening. This opening faces inwardly and downwardly towards the blood spreading plate on surface 57b. As the blood bubbles are returned inwardly and downwardly by the curved surface 66a of deflecting portion 66, they will be fed outwardly through opening 46 and will be spread outwardly toward the defoaming sleeve by deflecting surface 57b. In this area the blood bubbles may pass down the sides of the bubbler and through the defoamer to eliminate bubbles and for suitable filtering.

It has been found that in some previous bubbler assemblies wherein the nature of the outlet opening was such that it terminated in portions of decreasing dimension, these decreased areas of opening, under certain c rcumstances of operation, can cause higher velocities through the discharge opening which can result in the saturation of the defoaming means and filter in a localized area adjacent to and above the opening, which is undesirable and reduces the defoaming efficiency of the unit.

With the bubbler assembly of the present invention, the shape of opening 46 is such that the likelihood of any clogging occurring therein is substantially elimlnated. Moreover, the direct proximity of the surface 57b immediately below opening 46 encourages smooth blood flow by spreading the blood bubbles outwardly as they are discharged out of the opening 46.

The bubbler assembly of this invention promotes thorough intermixing of blood and eliminates stratification thereof by directing the blood through an upwardly ascending, generally S-shaped path as described. Throughout the path of travel of the blood, its course is channeled by means of rounded or inclined surfaces and no sharp edges or narrow angular recesses or the like are provided in the path of blood flow. The outlet opening for the blood is a wide, generally rectangular opening so as to eliminate the possibility of clogging due to the buildup of fragmentary matter. The inclined deflector plate below the opening spreads the blood out into thin sheets. From there the blood is free to flow along the sides of the bubbler such as in the relatively recessed areas and outwardly therefrom through the defoaming sleeve with the likelihood of clogging or backflow eliminated due to the free flow space afforded by the recessed configuration.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as some modifications may be obvious to those skilled in the art.

We claim:

1. A bubbler assembly for use with a blood oxygenator for forming films of blood in bubble form by directing oxygen into incoming blood to release carbon dioxide from the blood and transfer oxygen thereto, comprising: a substantially hollow, elongated housing forming internal chamber means for confining the flow of blood into a pre- 6 determined path; inlet means in the housing for directing blood and oxygen into the chamber means from exterior sources; outlet means in the housing generally remote from the inlet means for the passage of fluid and gases outwardly of the bubbler assembly; and means in the housing for dividing the internal chamber means so as to define a generally sinous continuous closed fluid passageway from the inlet means to the outlet means, said passageway including a lower segment in communication with the inlet means, an intermediate segment in communication with said lower segment and an uppermost segment in communication with the intermediate segment with the uppermost segment terminating in said outlet means, said outlet means facing toward the lower segment.

2. The bubbler assembly of claim 1 wherein the uppermost segment includes a deflecting portion adjacent the outlet means positioned relative to the path of blood flow in the uppermost segment to direct blood towards the lower segment as it is discharged through the outlet means, said bubbler assembly further including a planar blood deflecting surface below the outlet means positioned transversely to the path of blood flow exiting the outlet means.

3. The bubbler assembly of claim 2 wherein the deflecting portion includes a downwardly returned portion of the uppermost segment, with the outlet means comprising a terminal open end of the uppermost segment facing toward the lower segment.

4. The bubbler assembly of claim 3 wherein the bubbler assembly passageway defines a generally flattened, elongated S-shaped structure.

5. A bubbler assembly for a blood oxygenator comprising: a generally hollow, elongated housing including an internal chamber with inlet means in one portion of the chamber for admitting blood and oxygen to the in terior thereof and outlet means remote from the inlet means for the passage of fluid outwardly from the chamber; means defining a continuous closed passageway for the flow of fluid from the inlet means to the outlet means, the outlet means terminating in an opening with a planar blood deflector surface on the housing below the outlet means and positioned generally across the path of blood flow for spreading blood deposited onto the surface from the outlet means into thin films and directing the same away from the outlet means.

6. The bubbler assembly of claim 5 wherein the blood passageway includes plural tandem arranged segments in continuous communication with each other with the deflector surface being a portion of the housing defining one of the passageways and the outlet opening being closely spaced above the blood deflector surface.

7. The bubbler assembly of claim 6 wherein the plural segments include a lower and upper segment with the lower segment in communication with the inlet means and with the upper segment including a returned portion facing toward the lower segment and terminating in said outlet opening.

8. A bubbler assembly for a blood oxygenator comprising: a substantially hollow elongated housing having an internal chamber for confining the flow of blood in a predetermined path; fluid inlet means in the housing for admitting oxygen and blood thereinto; fluid outlet means in the housing remote from said inlet means; means for dividing the internal chamber into a plurality of segments so as to define a continuous closed passageway for the flow of fluid from the inlet means to the outlet means with the exterior walls of the housing including relatively recessed portions to provide a means for holding an enveloping defoamer sleeve relatively spaced from portions of the bubbler assembly housing.

9. The bubbler assembly of claim 8 wherein the plural segments are generally in tandem array including upper and lower segments, with the relatively recessed portions being formed by side wall portions of said upper and lower segments of the passageway which project laterally outwardly beyond adjacent portions of the housing.

10. The bubbler assembly of claim 8 wherein the passageway includes an intermediate segment connected to said upper and lower segment with the intermediate segment having side wall portions spaced inwardly from the lateral extent of the side wall portions of the upper and lower segments.

11. A bubbler assembly for use with a blood oxygenator for forming thin films of blood in bubble form by directing oxygen into incoming blood to release carbon dioxide from the blood and transfer oxygen thereto, comprising: a hollow housing forming internal chamber means for confining the flow of blood in a predetermined path; inlet means in the housing for directing blood and oxygen into the chamber means from exterior sources; outlet means in the housing generally remote from the inlet means for the passage of fluid and gases outwardly of the bubbler assembly; and means in the housing for dividing the internal chamber means so as to define a continuous closed fluid passageway from the inlet means to the outlet means,

said passageway including a first elongated segment, a 20 second elongated, centrally located segment, and a third elongated segment, the first segment being in communica- UNITED STATES PATENTS 3,058,464 10/1962 Broman 23----258.5 3,087,490 4/1963 Broman 23-258.5 3,112,746 12/1963 Gewecke et a1 23-258.5 3,256,883 6/1966 DeWall 23258.5 3,374,066 3/1968 Farrant 23-258.5 3,468,631 9/1969 Raible et a1. 23-258.5 3,488,158 1/1970 Bentley et al. 23-258.5

MORRIS O. WOLK, Primary Examiner B. S. RICHMAN, Assistant Examiner US. Cl. X.R.