US3515640A - Combination pump and oxygenator - Google Patents

Description

June 2, 1970 c. R. RUDLIN 3, ,6

, COMBINATION PUMP AND OXYGENA-TOR Filed Feb. 13, 1 968 3 Sheets-Sheet 1 INVENTOR CRAIQ- lauouN a 1 03% axmwe ATTORNEYS June 2, 1970 c. R RUDLIN COMBINATION PUMP AND OXYGENATOR '3 Sheets-Sheet 2 Filed Feb. 13, 1968 mw W HQ 5"; O m H 3 Q.

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- ATTORNEYS June 2, 1970 c. R. RUDLIN COMBINATION PUMP AND OXYGENATOR 3 Sheets-Sheet 3 Filed Feb. 13, 1968 INVENTOR HWHT w u I a WWW W fi mm Om m m l I I I I I I I l I I I I Creme '2. Izuoum BY Waw-gwflk I ium mac ATTORNEYS United States Patent O 3,515,640 COMBINATION PUMP AND OXYGENATOR Craig R. Rudlin, 202 Overlook Road, Richmond, Va. 23229 Filed Feb. 13, 1968, Ser. No. 705,067

Int. Cl. A61m 1/03 US. Cl. 195-1.8 11 Claims ABSTRACT OF THE DISCLOSURE A method and device for both circulating and oxygenating blood, said device having a flexible oxygen permeable bladder mounted in a surrounding bath of gaseous oxygen rich fluorocarbon liquid so that oxygen in the fluorocarbon passes through the bladder to oxygenate blood pulsatingly circulated through the bladder by cyclic pressurization of the fluorocarbon bath.

BACKGROUND OF THE INVENTION This invention is related to the field of pumping and gas absorption of liquids and is specifically related to the field of blood pumps and oxygenators.

Many pumping systems have been provided for the pumping of blood in conjunction with or Without an oxygenator so as to maintain the required circulation in a patient extracorporeally. Devices of this sort also have utility in providing and maintaining circulation in organs that have been removed from a donor but which must continuously receive a supply of oxygenated blood in order to avoid deterioration and remain viable.

It is the present practice for cardiac surgeons to employ pump-oxygenators during open-heart surgery. Such pump-oxygenators are usually referred to as heart-lung machines and are actually two distinct individual function providing systems operation in conjunction with each other. The first system is the pumping system which provides the circulation of blood; Whereas, the second system is the oxygenation system which provides for the absorption of oxygen into the blood. Such systems have often been extremely complicated and have, unfortunately, not always worked with the desired degree of satisfaction. Since many of the prior devices are quite complicated such as by the use of plural pumps, bubble traps, filters and the like, they are unfortunately susceptible to malfunction. Moreover, many of the previously known devices have, by virtue of necessity, required an inordinantly large working fluid volume which must be primed by a large amount of the patients own blood or by the use of additional donor-provided blood.

Yet another problem encountered with the presently known devices is that the valving and pumping means tend to produce trauma and hemolysis of the blood by virtue of rough or crushing action of the parts coming in contact with the blood.

None of the presently known devices provide a simple means for both the pumping and oxygenation of the blood.

SUMMARY OF THE INVENTION The subject invention comprises a gas-permeable bladder located in a bath of liquid having a high content of gaseous dissolved oxygen, but having its interior in communication with an inflow and an outflow line connected to a patient or extracorporeal organ for providing oxygenation and circulation of blood to the patient or organ. The bath of fluorocarbon liquid is maintained in a cylindrical enclosure and a reciprocable piston received within the cylindrical member serves to cyclically increase and decrease pressure on the exterior of the bladder so as to cause blood to flow into, and expand, the bladder 'ice during the time when the pressure of the fluorocarbon liquid is decreasing so as to cause the blood to flow out from the bladder when the pressure is increased on the fluorocarbon bath liquid. Cam operated valve means associated with the inflow and outflow lines serve to cause the blood expressed from the bladder to be directed into the outflow line. Similarly, blood from the inflow line is directed into the bladder during the expansion of the bladder when the pressure is decreased in the fluorocarbon bath surrounding the bladder. The oxygen contained within the fluorocarbon bath flows into the bag to oxygenate the blood during continuing pumping operation.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the preferred embodiment of this invention;

FIG. 2 is a top plan view of the preferred embodiment;

FIG. 3 is a sectional view taken along lines 33 of FIG. 2 and illustrating the parts in position at the termination of an inflow cycle of operation;

FIG. 4 is a sectional view identical with FIG. 3 but illustrating the parts in a different position of operation at the termination of an exhaust or outflow of blood from the preferred embodiment;

FIG. 5 is a sectional view taken along lines 5-5 of FIG. 3;

FIG. 6 is a sectional view taken along lines 6-6 of FIG. 2;

FIG. 7 is a sectional view taken along lines 77 of FIG. 6; and

FIG. 8 is a sectional view identical with FIG. 6 but illustrating the parts in a different operative, or open, position.

DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment of this invention comprises a pump-oxygenator which serves to pumpingly provide a circulating flow of blood and to simultaneously provide oxygen for the blood during the pumping thereof. The preferred embodiment can be connected to either a patient or to a donated organ which is desired to be maintained in a viable condition.

In any event, the device is mounted on a support plate 18 conventiently adjacent to a source from which blood flows into an inflow tubular line 20 and to which blood is returned by an outflow line 22. Lines 20 and 22 are formed of plastic or other suitable non-toxic material which is commercially available. The tubing presently employed is made by US. Stoneware Company, Akron, Ohio, and sold under the trademark Tygon and has an inside diameter of 4 inch and a wall thickness; any smaller tubing results in hemolysis of the blood. Line 20 passes through a valve 24 which is cam actuated to compress the line to prevent the flow of liquid therethrough at desired cyclically timed intervals. Similarly, line 22 passes through a second valve 26 which is also cam actuated to cyclically compress the line to prevent the passage of liquid therethrough. The construction of these valves is discussed in detail hereinafter.

Each of lines 20 and 22 is connected to a bulb shaped T-fitting 28 which is fixed to an end plate 30 of a generally cylindrical bladder enclosing assembly generally designated 32 in FIG. 1. The bladder enclosing assembly 32 also includes an apertured rear plate 34 which is connected to plate 30 by four connecting rods 36 which extend through plates 30 and 34. A tubular cylindrical member 38 formed of plastic or other suitable material is received in circular grooves on the interior sides of plates 30 and 34 as shown in FIG. 3. Plates 30 and 34 can be adjusted toward each other by nuts 40 attached to the ends of rods 36 in an obvious manner. Consequently,

3 cylindrical member 38 can be tightly clamped between the plates and 34 to provide a fluid tight seal.

Fitting 28 has a central conduit 41 which extends through a central opening in plate 30 as shown in FIG. 3, and which has the mouth of a balloon-like bladder member 42 snugly fitted over its innermost extremity in a liquid tight sealed manner. Bladder member 42 is located completely within the interior of cylindrical member 38.

Apertured plate 34 is provided with an aperture through which a rod 44 of a piston 46 extends. Piston 46 is concentrically received in a liquid-tight relationship within the interior bore of cylindrical member 38 but is reciprocable along the axis of the cylindrical member. Seal members 48 extending about the periphery of the piston serve to maintain a liquid-tight relationship between the interior of cylindrical member 38 and the piston.

Bladder 42 is of flexible construction and is quite similar to a common balloon in shape and appearance. However, bladder member 42 is formed of gas-permeable medical grade silicone rubber of the type manufactured by Dow Corning and sold under the trademark Silastic. Although bladder 42 will allow the passage of gas in a manner similar to osmosis, it will not allow the passage of liquid through its wall portions. The bladder 42 is completely immersed in a bath of fluorocarbon liquid which has the capacity of absorbing a large amount of gaseous oxygen. Since the liquid bath 50 has a large amount of absorbed gaseous oxygen, it has the propensity for giving up the oxygen, to allow the oxygen to pass through the walls of bladder 42 to oxygenate blood contained on the interior of the bladder. The fluorocarbon liquid referably employed for the bath is a medical grade liquid manufactured and sold by the Minnesota Mining and Manufacturing Company and which is designated FX80 by the manufacturer. The designation FX80 is the designation applied by the manufacturer to its medicinal grade fluorocarbon liquid derived from a commercial grade liquid which is designated FX-75 and which is fully described in a bulletin published in 1965 by the manufacturer and entitled, Technical Information 3M Brand Inert Fluorochemical Liquids. However, other liquids capable of providing gaseous oxygen could also be employed if desired.

A driving and timing means generally designated 52 is provided for reciprocating piston 46 and actuating valves 24 and 26 in timed relation with respect to each other and other parts of the device. Means 52 also in cludes an electric motor 56 driving a step-down gear box 58 which, in turn, drives an output timing shaft 60. The output timing shaft 60 has a piston actuating eccentric member 62 keyed for rotation therewith and which serves to reciprocate a drive link 64 connected by a pivot pin 66 to a clevis member 68 attached to the outer end of piston rod 44. Therefore, rotation of shaft 66 will cause eccentric member 62 to reciprocate drive link 64 and consequently provide for reciprocation of piston 46 within the cylindrical bore of cylindrical member 38. Moreover, valve actuating earns 70 and 72 are respectively keyed to shaft 60 in association with valves 24 and 26 for actuation of these valves. Each of the valves is identical but each valve is actuated at different time periods by virtue of different angular displacements of the respective actuator cams 70 and 72 with respect to shaft 60.

Each valve comprises a valve block 74 (FIGS. 6, 7 and 8) which is attached to support plate 18 by screws or other suitable connectors. The upper portion of each valve block is provided with a rotary bearing 76 in which timing shaft 60 is rotatably supported. A horizontal bore is provided in each valve block 74 through which the respective flow lines pass as shown in FIGS. 7 and 8. A vertical bore connects with the horizontal bore and is provided with a reciprocable cam-follower pusher rod 78 which engages the respective cam associated with each of the valves. The natural flexibility of the inflow and outflow lines and the pressure of blood within the lines serves to constantly urge the push rods toward the respective cam members. However, supplemental coil springs encircling members 78 could be employed to supplement this action if desired.

Each of cams 70 and 72 is provided with a high rise portion and a lower rise portion. The high rise portion is illustrated in contact with the push rod 78 in FIG. 6 and causes the push rod to close the flow line as shown. However, when the cam rotates to the position illustrated in FIG. 8, the push rod is then free to move upwardly so that the respective line is open to allow passage of blood therethrough. The particular valve construction employed results in a minimum of blood damage, trauma and clotting and has proven to be highly satisfactory. However, other type valves might be used if desired.

Turning now to FIGS. 4 and 5, it will be seen that a Small gas pocket or space 80 is provided above the top surface of liquid bath 50 to enable a cushioning effect during pumping and to also enable additional absorption of oxygen by the liquid bath. This pocket would normally be filled with oxygen. A small line 82 extends from and through plate 30 for connection to a pressure gauge or other pressure monitoring means for detection and measuring of the pressure on the interior of cylindrical member 38. Consequently, the pressure can be constantly monitored to prevent either high or low pumping pressure which might cause damage to the source receiving and providing the pumped blood. Moreover, a liquid line 84 is connected to a valve 86 extending through a plate 30 so that the liquid bath 50 can be replenished if desired or necessary during the pumping operation. It should also be noted that it would be possible to provide gaseous oxygen through line 84 if such would be needed.

When the preferred embodiment is being used, line 20 is connected to a vein of the source (either a complete patient or a separate organ) and line 22 is usually connected to an artery. However, the connections may be reversed in certain instances. In any event, blood to be pumped enters the preferred embodiment through line 20. and oxygenated blood is pumped outwardly from line 22. Motor 56 is drivenv at a desired rotational rate so that piston 46 is reciprocated between the respective positions illustrated in FIGS. 3 and 4 to give the required desired number of pumping strokes per minute. The position of the parts illustrated in FIG. 3 illustrates the beginning of a pumping cycle and the position illustrated in FIG. 4 llustrates the end of a pumping cycle. When the piston is in the FIG. 3 position, valve 24 is closed by cam 70 to assume the position illustrated in FIG. 6 and valve 26 is simultaneously opened to assume the position illustrated in FIG. 8. Consequently, the subsequent movement of piston 46 to the left causes blood within bladder 42 to be pumped outwardly through line 22. However, when the piston reaches the position illustrated in FIG. 4, the valve conditions are reversed by their respective cams so that valve 26 is then closed and valve 24 is opened and subsequent movement of the plunger to the FIG. 3 position will result in a lowering of pressure within the confines of cylindrical member 38 so as to consequently draw blood into the bladder. This blood will then be expelled on the next cycle of pump operation when the piston 46 moves from the FIG. 3 position to the FIG. 4 position.

Blood on the interior of the bladder engages a first or inner surface of the bladder whereas the gaseous oxygen containing liquid bath 50 contacts a second or outer surface of the bladder and passes through the thin flexible membrane forming bladder 42. However the rate of passage through the walls of the bladder will obviously vary in accordance with the pressure within the cylindrical member 38. The thickness of the bladder wall and speed of operation of the motor will also affect the rate of passage. In any event, the passage of oxygen into the interior of the bladder serves to oxygenate the blood and it will therefore be obvious that the subject device provides both oxygenation and pumping of the blood.

While various modifications of the preferred embodiment will be apparent to those skilled in the art, it should be strictly understood that the spirit and scope of this invention is determined solely by the scope of the appended claims.

What I claim is:

1. A method of concurrently pumping and oxygenating blood comprising the steps of initially bringing low-oxygen content blood into contact with one side of a thin flexible liquid-impermeable membrane having the characteristic of passing oxygen from a gaseous oxygen rich liquid engaging the other side of said membrane, increasing the pressure of said liquid to simultaneously pump said blood and cause oxygen from said liquid to pass through said flexible membrane to oxygenate said blood.

2. The method of claim 1 wherein said thin flexible membrane is formed of silicon iubber and said oxygen rich liquid is fluorocarbon liquid.

3. A method of simultaneously pumping and oxygenating blood comprising the process of introducing the blood into a variable volume space at least partially defined by one-side of a thin flexible element of gas-permeable liquid-impermeable material which has its other side engaging a bath of oxygen rich liquid and cyclically varying the pressure of the bath to cause cyclic inflow and outflow of blood with respect to the variable volume space while simultaneously oxygenating the blood.

4. The invention of claim 3 wherein said thin flexible element is formed of silicon rubber and said oxygen rich liquid is fluorocarbon liquid.

5. A pump-oxygenator for pumping blood and concurrently oxygenating the blood, said pump-oxygenator comprising a closed container, an oxygen rich liquid bath in said closed container, a thin flexible liquid-impermeable membrane having a first surface in contact with blood to be pumped through closed conduit means and a second surface in contact with said oxygen rich liquid bath in said closed container and means for cyclically varying the pressure of said liquid bath in said closed container wherein said thin flexible membrane is formed of material which permits oxygen from said oxygen rich liquid to pass through said flexible membrane so that cyclic variation of the pressure of said oxygen rich liquid causes a concurrent flexing of said flexible membrane to result in simultaneous pumping and oxygenation of blood in contact with said membrane.

6. The invention recited in claim 5 wherein said flexible membrane is in the form of a bladder member having a mouth portion connected to said closed conduit means which comprises inflow and outflow lines with said first surface comprising the interior surface of said bladder member and said second surface comprising the exterior surface of said bladder member.

7. The invention of claim 6 wherein said bladder member is mounted in said closed container which maintains said oxygen rich liquid bath in contact with said bladder member.

8. The invention of claim- 7 wherein said closed container is a hollow cylinder and said means for cyclically varying the pressure of the oxygen rich liquid bath includes a piston mounted for reciprocation in said cylinder.

9. The invention of claim 8 wherein said means for cyclically varying the pressure of the oxygen rich liquid bath additionally includes timing drive means for moving said piston in a first direction to increase the pressure in said cylinder and for simultaneously closing a valve on said inflow line while simultaneously opening a valve on said outflow line so that blood contained within said bladder member will be expelled outwardly into said outflow line and for subsequently moving said piston in a reverse direction to decrease the pressure in said cylinder and for simultaneously closing the valve in said outflow line while simultaneously opening the valve in said inflow line so that blood from said inflow line will flow into said bladder.

10. The invention of claim 9 wherein said timing drive means includes a drive shaft having an eccentric cam functionally connected to said piston for reciprocating said piston and first and second valve actuating cams fixedly connected to said shaft for actuating said valve means associated with said outflow and inflow lines.

11. The invention of claim '10 wherein each of said valves associated with said outflow line and said inflow line comprises a block member having a transverse passageway through which one of said lines extends and a bore extending outwardly from said passageway and mounting a reciprocable pinch rod having one end engaging said line and its other end in position to be engaged by one of said cammembers.

References Cited UNITED STATES PATENTS 2,105,200 l/1938 Phelps.

2,412,397 12/1946 Harper l03l48 2,689,530 9/1954 Harvey l03148 2,917,751 12/1959 Fry et a1.

3,015,331 l/l962 Warrick 23258.5 3,148,624 9/1964 Baldwin l0344 3,183,908 5/1965 Collins et al. 23258.5 3,218,979 11/1965 Baldwin .l03-44 3,333,583 8/1967 Bodell 2l032l XR 3,359,910 12/1967 Latham 103149 XR 3,459,310 8/1969 Edwards 23-2585 XR JOSEPH SCOVRONEK, Primary Examiner a B. S. RICHMAN, Assistant Examiner US. Cl. X.R.

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