US 3291568 A
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Dec. 13, 1966 R. D. SAUTTER CARDIO-PULMONARY BY-PASS OXYGENATOR UNIT Filed April 6, 1964 RECIRCULATING VENOUS BLOOD 42 SOURCE LOOD RETURN INVENTOR Richard D. Soufler Luzo 8: Barry OX YGEN SUPPLY Attorneys United States Patent O 3,291,568 CARDIO PULMONARY BY-IASS OXYGENATOR UNIT Richard D. Sautter, 806 E. 17th St, Marshfield, Wis. Filed Apr. 6, 1964, Ser. No. 357,484 7 Ciaims. (Cl. 23-2585) This invention relates to a cardio-pulmonary by-pass unit particularly designed for use in the hypothermic low flow hemodilution technique of total body perfusion.
The idea of oxygenating the circulating blood outside of the body by artifical means is not new and the need for a successful blood oxygenating heart-lung apparatus has been recognized for many years. In the development of such devices oxygenation of the blood by bubbling oxygen through the desaturated venous blood has been found to be quite successful and one of the most practical ways in the point of rate of oxygenation required for continued recirculation of the blood. Many devices have been developed to accomplish this result, but have for the most part been impractical for emergency and regular use because of the time required to set up the unit, complications in autoclaving and difficulty of disassembly.
One of the primary objects of the present invention is to provide an improved blood oxygenating unit which overcomes the above limitations.
Another object of the present invention is to provide a blood oxygenating unit that is inexpensive to manufacture and requires little or no maintenance.
Another object of the present invention is to provide a blood oxygenating device that can be assembled in a minimum of time.
A further object is to provide a blood oxygenating device that combines a heat exchanger, blood oxygenator and a reservoir into a single integral unit.
A further object of the present invention is to provide a blood oxygenating unit that is absolutely fail-safe in that it is free of internal leaks.
A still further object of this invention is to provide a unit that is readily adaptable to autoclaving.
A still further object of the present invention is to provide a blood oxygenating unit that has good heat exchange efiiciency for the surface area available.
These objects are accomplished by forcing oxygen under a pressure of 10 liters/min. through a perforated disc which disperses the oxygen in the form of minute bubbles as it enters the oxygenating column. Blood is admitted to the oxygenating column at a point just above the dispersed oxygen so that the oxygen bubbles through the blood as it rises in a center vertical column. The oxygenated blood is carried from the top of the column into a defoaming canister which eliminates the foam in the blood prior to its return to a reservoir which surrounds the center column. A heat exchange jacket is provided between the oxygenating column and reservoir and also around the defoaming canister through which a heat exchange medium is passed under controlled temperature conditions. A flat spiral strip is wound around the outer periphery of the heat exchange jacket within the reservoir and is connected to the bottom of the defoaming canister by a dependent loop tube which prevents the admission of air bubbles to the reservoir. The defoamed blood is carried gently around the outer surface of the heat exchanger by the spiral strip downward to the bottom of the reservoir where it is collected temporarily prior to its return to the patient. The temperature of the heat exchange medium which flows through the heat exchangers is controlled only to the extent necessary to maintain the desired temperature of the vital organs of the body.
3,2915% Patented Dec. 13, 1966 In cleaning the device, the cap used to hold the perforated disc is quickly removed to expose the interior surface of the oxygenating column. The defoaming canister is sealed to the top of the oxygenating column by tubing which can be lifted off of the column to open the column at both ends. The inlet and outlet tubes are removed for autoclaving. The reservoir can be cleaned by removing the outer plastic wall of the unit to expose the spiral strip. When the assembled oxygenating unit is to be placed in an autoclave, the blood inlets and outlets are temporarily covered with a qauze which is removed when the connections are to be made to the corresponding tubes.
Other objects and advantages will become more readily apparent from the following detailed description when read in connection with the accompanying drawings, in which:
FIG. 1 is a side view in sectional elevation of the blood oxygenating apparatus.
FIG. 2 is an exploded view of the lower portion of the oxygenating apparatus to show the oxygen dispersing system.
FIG. 3 is a view of the dispersion disc.
In the embodiment shown in the drawings, the cardioplumonary by-pass unit includes a vertical oxygenating column 10 and a heat exchange jacket 12 both made of a chemically inert material such as stainless steel. The jacket is coaxially mounted on the column and silver brazed thereto at 14 and 16 to form a Water tight joint.
The inner surface of the column and the outer surface of the jacket are highly polished to reduce trauma in the blood.
A flange 18 is secured to the upper end of the water jacket and a flange 2%) is secured to the lower end of the jacket. A flat spiral strip 22 is spirally wound around the outer surface of the jacket between the flanges and is silver brazed thereto to form a fluid tight connection. A mayon plastic tubing 24 is slipped over the flanges and sealed thereto by hose clamp 26, 28 to form reservoir 30 around the outer surface of the jacket. The plastic tube fits the strip snugly and forms a seal with the outer edge of the strip so that it acts as a bubble trap.
The lower end of the column is threaded at 32 to receive a cap 34 which supports an oxygen inlet and dispersion unit 35. Oxygen which is admitted to oxygen inlet 36 will be dispersed through perforations 40 in the disc. Venous blood which is admitted to the column through inlets 42 and 44 will be foamed by the dispersed oxygen and will rise in the column. One of the venous blood inlets is connected to receive blood from the cavae or right heart while the other inlet is used for the cardiotomy suction return.
The upper end of the'column is connected to an inlet 46 on a defoaming canister 48 by means of a mayon plastic tube 50 which is sealed to the column and inlet by hose clamps 52. The foamed blood which rises in the column will overflow into the canister and will pass through a defoaming material such as a silicon coated stainless steel sponge enclosed in a fine mesh nylon filter which is located within the canister. A heat exchange jacket 70 is provided around the outside surface of the defoaming canister. A mayon plastic tube 54 may be connected to an opening 55 in the bottom of the canister and taped to the upper portion of the side of the heat exchange jacket to show the height of blood within the canister.
In the unit presently being used, the oxygenating column is approximately 21.5 inches long with an internal diameter of 1.180 inches and an outer diameter of 1.250 inches. The heat exchange jacket is 17.25 inches in length with an internal diameter of 1.430 inches and an outer diameter of 1.50 inches; The reservoir which is formed by the mayon plastic tube is 15.75 inches long with an internal diameter of 2.50 inches, thus allowing approximately 1.00 inch between the water jacket and the tubing for the flat spiral strip. The top of the oxygenating column is connected to the bottom of the defoaming canister by a mayon plastic tube approximately four inches long and having an internal diameter of one and one-half inches.
The defoamed oxygenated blood from the canister will flow through outlet 56 into a mayon plastic tube 58 approximately 24 inches long which is looped at 57 and connected to reservoir inlet tube 60 in flange 18. The dependent loop acts to prevent any bubbles from entering the reservoir and therefore acts as an additional protection against air embolism. The oxygenated blood will flow gently down the flat spiral wound strip to the bottom of the reservoir where it is pumped out through reservoir outlet tube 62. A vent tube 64 is connected to opening 66 in flange 18 and is taped to the side of the canister to compensate for changes in the pressure in the reservoir.
Water for the water jacket is admitted to the jacket through inlet 68 and rises to the top of the jacket where it leaves through outlet 70. A mayon plastic tube 72 is connected between the water jacket outlet and inlet 74 to water jacket 70 on the defoaming canister. The water will rise in the canister jacket to outlet 76 and will then be returned to a water pump for recirculation. The
.water temperature used in the unit is controlled in response to the requirements of the patient. With the water jacket located between the oxygenating column and the reservoir, the temperature of the incoming and outgoing blood can be better controlled.
The oxygen inlet and dispersion unit (FIGS. 2 and 3) has a steel washer 78 positioned on the lower end of the vertical oxygenating column, a disc 38 positioned below the steel ring and a rubber O-ring 80 positioned below the disc. The washer and disc are held in place by a seat 82 which underlies the disc and has its outer periphery sealed to the inner surface of the column by the rubber O-ring. Seat 82 has a central aperture 84 which is aligned with the inlet tube 36 to allow for admission of oxygen to the space below the disc.
In preparing the unit for autoclaving, the blood outlet, the two blood inlets and the oxygenator inlet tube are covered with gauze held in place with masking tape. Autoclaving is then done with the unit completely assembled. The gauze is removed just prior to connection of the appropriate lines to the connectors. These connections can be made sterilely without the use of gowns or gloves.
The oxygenator is designed for quick setup and is usually stored in an assembled condition; in use, it is merely set up in a vertical position by any appropriate means. The proper tube connections are made to the various tube inlets and outlets and to the proper pumps. Water is continuously pumped through the water jacket at a controlled temperature to bring the apparatus up to operating temperature and maintain it at that temperature. When the pumps are started after the proper tube connections have been made, desaturated venous blood will flow by gravity through the inlet tubes and into the bubbling column. Oxygen is supplied under a pressure of 5-10 liter/min. to the oxygen inlet and will be dispersed by the disc in the form of small bubbles which aerate the blood in the column. The bubbling column slowly fills with an uninterrupted rising column of bub bles which are in heat exchange relation to the heat exchanger until the blood overflows into the defoaming canister. The defoa-ming material will strip any occluded bubbles from the oxygenated blood as it flows to the bottom of the canister.
The oxygenated and defoamed blood then flows through the looped tube to the upper end of the spiral strip which 'carries the blood gently downward around the surface of the water jacket. Since the temperature of the wall of the water jacket is varied according to the requirements of the patient, the temperature of the blood as it flows into the reservoir will be changed to the desired temperature. A small amount of oxygenated blood is collected in the reservoir before the return pump is started to prevent the possibility of drawing air from the reservoir. The vent tube in the top of the reservoir allows for variations in pressure in the reservoir by the incoming and outgoing blood.
This apparatus can be quickly and easily disassembled for sterilizing by merely removing all tubing, unscrewing the end cap for the oxygen inlet and dispersion unit and removal of the defoaming canister. The oxygenating column will then be open at both ends and the reservoir and heat exchange jacket will be open at both the inlet and outlet. Because of the simplicity in setup and autoclaving of this unit, it has been found to be usable both for emergency and general use.
Although only one embodiment of the invention has been shown and described, it should be apparent that various changes and modifications can be made in this unit without departing from the scope of the appended claims.
What is claimed is:
1. A blood oxygenating unit comprising a chamber having an inlet at the bottom and an outlet at the top,
a heat exchange jacket surrounding said chamber, means for circulating a heat exchange medium through said jacket at a controlled temperature,
means for delivering venous blood to the inlet to said chamber,
means for admitting oxygen into said chamber to force the venous blood to rise in the chamber,
def-oaming means connected to the outlet of said chamber to defoam the blood as it flows from the chamber,
a flat strip wound spirally around and secured to the outside of said heat exchanger a removable tubular plastic member mounted on the outer edge of the flat strip to form a reservoir around the outside of said jacket.
tube means for delivering defoamed blood from the defoaming means to the top of the spiral strip, and
tube means for removing blood from the bottom of said reservoir as needed.
2. An oxygenating unit according to claim 1 wherein said means for delivering defoamed blood to the top of said spiral strip comprises a tube looped to prevent the passage of air into said reservoir.
3. An oxygenating unit according to claim 1 wherein said defoaming means includes a water jacket surrounding said canister and means for delivering the heat exchange medium from said heat exchange jacket surrounding said chamber to the heat exchange jacket surrounding said defoaming means.
4. A blood oxygenating device comprising a vertical cylinder open at both ends,
a cylindrical heat exchange jacket having an inlet and an outlet coaxially mounted on said cylinder and sealed thereto means for circulating a heat exchange medium through said jacket,
a flat strip spirally wound around said jacket with its inner edge sealed to the outer surface of said jacket,
a plastic tube coaxially mounted on said cylinder in sealed engagement with the outer edge of said strip to form a reservoir,
an oxygen inlet and dispersion means positioned in the lower open end of said chamber, and
inlet means in said cylinder immediately above said oxygen inlet and dispersion means to admit desaturated blood to said cylinder, defoaming means connected to the open upper end of said cylinder, tube means connecting the defoaming means to the top of the spiral strip and outlet means at the bottom of the reservoir to allow oxygenated blood to be removed from the reservoir.
5 6 5. A blood oxygenating unit according to claim 4 means for circulating a heat exchange medium through including flange means at both ends of said spiral strip said second cylinder, and to seal the ends of said plastic tube to said Water jacket to tube means for removing oxygenated blood from the form a reservoir around the outer periphery of said reservoir. jacket. 5 7. A blood oxygenating unit according to claim 6 6. A blood oxygenating unit comprising a first cylinder wherein said defoaming means includes a dependent loop open at both ends, tube means for preventing bubbles from entering the a second cylinder coaxially mounted on said first cylreservoir.
inder and having both ends sealed thereto a spiral strip mounted about the outer surface of said second 10 References Cited y the Examiner cylinder to form P3. spiral flow path from the top of UNITED A S PATENTS the cylinder to the bottom of the reservoir, a third flexible cylinder coaxially mounted on said 2730337 1/1956 Roswell 165156 X Spiral Strip and sealed thereto 2,870,997 1/1959 Soderstrom 165141 dispersion means for admitting oxygen to th lower 15 2,934,067 4/1960 Call/1n 128-214 end of said first cylinder, OTHER REFERENCES tube means in close proximity to sa1d dispersion means for admitting venous blood to said first cylinder, F et Hlgh Output Bubble Oxygenator Wlth defoaming means connected to the other end of said Vanable Oxygenafing Chamber for cardiac Bypass cylinder and to said third cylinder for delivering 20 Surgery May 19601 772-83 defoamed blood from said first cylinder to said third cylinder, said third cylinder forming a reservoir RICHARD GAUDET Pnmary Examiner about said second cylinder, DALTON L. TRULUCK, Examiner.