US3098480A

US3098480A - System for fluid transfusion

Info

Publication number: US3098480A
Application number: US72376A
Authority: US
Inventors: William D Worthington
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-11-29
Filing date: 1960-11-29
Publication date: 1963-07-23
Anticipated expiration: 1980-07-23
Also published as: DE1245039B; GB931484A

Description

y 1963 w. D. WORTHINGTON 3,098,480

SY FOR FLUID Filed Nov. 29, 1960 2 Sheets-Sheet 1 i j 7- 4 Mil/4M D. WORTHINGTON United States Patent M SYSTEM FQR FLUED TRANSFUSION William D. Worthington, Charlotte, Vt. Filed Nov. 29, 1960, Ser. No. 72,376 9 Claims. (or. 128-214) This invention relates to a new fluid transfusion system and includes an improved apparatus for gradually replacing the blood of a patient, usually an infant, by an equal amount of bank blood from a source of supply.

The apparatus of the present invention is particularly adapted for the treatment of erythroblastosis fetalis which is brought about by the sensitization of an Rh negative mother to her Rh positive child inutero; in other words, as is well known in the medical profession, the Rh negative mother may form an Rh antibody which finds its way into the blood stream and body fluids of her Rh positive infant. This antibody causes the destruction of Rh positive red blood cells and results in the formation of bilirubin which is potentially toxic, and, may cause extensive damage or even fatality to the new-born.

Generally speaking, it is, therefore, within the scope of this invention to provide an improved blood-exchange transfusion system and apparatus for accomplishing a treatment that comprises: (1) the gradual, continuing intermittent withdrawal of the infants blood while at substantially the same time transmitting the simultaneous injection into the infants vascular system of a compatible adult blood from a source of supply; (2) the constant control of venous pressure and adjustment of blood volume and (3) the addition of calcium, anticoagulant or other medication.

Heretofore, it has been generally customary to perform all of the functions of the improved apparatus disclosed by this invention by a manual operation and a pumping system comprising the use of glass syringes and two threeway stop cocks.

One of the basic concepts of the present invention involved is one of alternately removing small aliquot portions of an infants circulating blood and substantially simultaneously replacing it with an equal amount of compatible blood from an adult bank.

Another object of the invention is to provide an improved mechanical means including a motor driven automatic blood exchange transfusion apparatus or" simple, compact construction for the continuing intermittent replacement of the infants blood with bank blood of a compatible group.

' A further object of the invention is to provide an improved mechanical, automatic blood-exchange apparatus using a single catheter for a continuing, alternating blood withdrawal and blood injecting operation.

Still a further object of the invention is to provide a simple automatic blood-exchange transfusion apparatus which can be easily and quickly diseassembled for cleaning the permanent parts and replacing the disposable plastic elements thereof.

A still further object of this invention is to provide a simple fluid apparatus employing a direct, continuous infusing operation.

These and other objects and advantages of the present invention will become apparent by reference to the following drawings in which:

FIG. 1 is an elevational view of the right side of a preferred embodiment of the transfusion apparatus with the housing shown broken away in part;

FIG. 2 is a sectional front elevation View of the same embodiment taken along lines 22 of FIG. 1;

FIG. 3 is an enlarged detailed diagrammatic schematic top plan view on line 3-3 of FIG. 2;

3,098,480 Patented July 23, 1963 FIG. 4 is an elevational view of the rear of the preferred embodiment of the invention;

FIG. 5 is a bottom plan view of the same embodiment of the invention;

FIGS. 6 and 7 are schematic diagrams illustrating the principle of operation of the blood-exchange transfusion apparatus.

With reference to the drawings and more particularly to FIGS. 1 and 2, the upper portion of the apparatus is enclosed with a cover 1 which may be of any suitable material such as metal or plastic that is provided with a suspension lug 2 for attachment to an appropriate support. The bowl shaped cover provides therebeneath a housing which is separated into two compartments by an elongated L-shaped divider Wall 3 which thereby provides two chambers 4 and 5. The first of these chambers, 4, houses an electric drive motor 6, partially shown in FIG. 1, and thereabove is positioned an input terminal for an external electrical power connection 7 and an on-off operating switch 8 is shown secured to the sidewall of cover 1. A drive shaft 9 (FIG. 2) carried by the electric motor 6 extends through the divider wall 3 into the adjacent chamber 5 and supports concentrically therewith a spur gear 10. A complemental spur gear 11 is rotatably mounted on a stub axle 20 suitably secured to wall 3 and is mranged to be driven by spur gear 10 carried by the shaft of the motor 6. A crank or connecting rod 12 is eccentrically mounted on spur gear 10 by means of an ofistanding stud providing a pivot pin 13- that extends downwardly through one of several apertures, such as at 28, in the horizontal leg of wall 3 and is secured by means of wrist pin 14 to the piston 15. A second crank or connecting rod 16, also eccentrically mounted on spur gear 11 by means of an ofistanding stud providing a pivot pin 17, extends downwardly through the second of said apertures, such as at 29, and is suitably secured at its depending end to a wrist pin 18 carried by another piston 19. The

aforesaid pistons

15 and 19 are reciprocably positioned in plastic cylinders 25 land 26, respectively. The

plastic cylinders

25 and 26 are supported at their lower extremities in annular recesses 3d and 31 in the top wall of a rectangular valve block 27 (FIG. 2) and at their upper ends by counterbored recesses provided in the lower horizontally extending face of the wall 3 and in substantial alignment with the apertures 28 and 29 through which said connecting

rods

12 and 16 extend. It will be noted that

sealing rings

32 and 33 are secured about the lower external portions of

cylinders

25 and 26 where these elements are conjoined with the valve block 27 in order to prevent leakage therebetween.

A cam 34 is mounted integral with shaft 9 carried by the electric motor 6. Substantially one half of the periphery of said cam 34 has a large radius of curvature ex-tend ing beyond the teeth of the gear to which it is arranged in iace-to-face relation, while the other half has its radius of curvature sufficiently reduced for a purpose now to be described. A rotatable cam following roller 35 is secured by means of a suitable pivot pin 4% to a generally Z-shaped rocker element 41 which oscillates about pin 4-2 positioned in a slotted portion 42a in the horizontal leg of wall 3. The lower extremity of rocker arm 41 is notched, as at 4311 (FIG. 1), the parallel legs thereby formed being bifurcated as at 43 and 44 and adapted to straddle a horizontal pin 49, associated with the reduced portion of an operative element now to be described.

Valve block 247 is horizontally apertured throughout its entire length substantially medially of the end wall 45 to provide a cylindrical bore 47 which is adapted to receive in reciprocable relation therewith a barrel-shaped valve spool 46. From an examination, particularly of FIGS. 1 and 2, it will be noted that the bore 47, adapted to receive valve spool 46, is located in such a manner that its longitudinal axis passes immediately beneath and substantially centrally of the

cylinders

25 and 26. The reduced end portion 48 integral with said valve spool 46 extends beyond valve block 27 and is amanged to be associated with the bifurcated portion provided at the distal lower end of rocker arm 41. The reciprocable valve spool 46 is provided with .suitable spacedly arranged annular grooves 50 and -1 which are to be operatively associated with cylinder 26 and a second set of

annular grooves

52 and 53 also carried thereby are operatively associated with and positioned beneath cylinder 25. (See FIG. 3.) The valve bore 47 is closed at its end opposite from the rocker arm 41 with a hand screw 54 which may abut a suitable compression spring 55 adapted to confront the said spool 46. It Will be apparent that spring 55 urges said valve spool against the rocker arm 41 thus forcing its upper pivotal end to follow cam 34. To those skilled in the art it will be manifest that any suitable type of spring device may be associated with the rocker arm 41 to accomplish this purpose. For example, the upper extremity of arm 41 could be provided with an aperture in which could be held one leg of a tension spring with its other leg portion being secured to a pin provided adjacent to spur gear 11 on the wall 3.

With more particular reference to the valve block 27 and as best seen in FIG. 3, there are provided on the top wall linearly and vertically

spaced ports

56 and 57 within the confines of the area beneath cylinder 25 and a pair of

like ports

58 and 59 are vertically arranged within the confines of the area beneath cylinder 26. The rear wall 60 of valve block 27 is horizontally apertured at 65 and 66 adjacent to cylinder 25 and a similar series of horizontal apertures are provided at 67 and 68 adjacent to cylinder 26. From a further examination of FIG. 3 it also will be noted that the pair of

apertures

56 and 57 confined as indicated are in substantial alignment with those identified as 65 :and 66 that are positioned in the rear wall 60. Also, that

apertures

58 and 59 confined within and beneath the cylinder area 26 are in alignment with the

apertures

67 and 68 that are also provided in the rear wall 60. The sum total of all of the aforesaid apertures serve as a means of communication between the respective cylinders through the medium of suitable plastic tubi-ng extending between the valve block, the fresh source of blood supply, the receptacle for old blood storage and that of the infant, as will be more clearly described later in the specification. Furthenmore, from FIG. 3 it will be clear that the

ports

56 and 57 positioned beneath cylinder 25, as well as ports 58 land 59 which are positioned beneath cylinder 26, are appropriately spaced in such a manner that in one position of the valve spool 46 the annular groove 56 thereon is in registration with vertical port 59, as well as horizontal aperture 68. At the same time, the annular groove 52 of the spool is in registration with vertical port 57 and horizontal aperture '66. Upon operation of the spur gears, as previously described, the valve spool 46 will be reciprocated to a new position and groove 51. of the spool will be al-ign ed with vertical port 58 and horizontal aperture 67, while at the same time annular groove 53 thereon will be in alignment with vertical port 56 and horizontal aperture 65.

A pair of vertically disposed

posts

69 and 70 secured, such as by threading into the horizontal leg of divider wall 3, are adapted to pass through apertures provided in the valve block 27 so that it may be held unitarily relative to said housing by means of thumb screws 71 and '72 (see FIGS. 1 and 5).

Referring now to FIGS. 4 and 5, a pair of

parallel posts

75 and 76 are fixedly mounted by any suitable means such as by bolts and arranged to depend from the ex ternal back wall of housing 1. The thumb screws 81 and '82 engage the threaded lower portions of said posts thereby securing the clamping collars 83 and 8 4 firmly against the retaining plate 85. The retaining plate 85 is provided with bifurcations generally simulating two semi-circular cutout portions 86 and 87 adapted to receive and support therein in upright position two cylin drical plastic bottles 88 and :89 having

bottom plates

91 and 90, respectively. From FIG. 1 it will be observed that the plastic bottle :88 (both plastic bottles being similar in this respect) has a reduced annular portion adapted to be received in one of the bfurcated portions more clearly shown in FIG. 5. Each of the plastic bottles are pro vided with depending nipples arranged to receive plastic tubing extending from the bottom of the bottle to the nipples provided on the rear surface 60 of valve block 27. As best shown in FIG. 4 the

covers

96 and 97 secured to the top of plastic bottles 88 and

S9 carry valves

98 and 99 which function as mechanical air traps for releasing any air that is incorporated in the blood flow. The valves or air traps can be actuated by operation of

levers

102 and 103 pivotally mounted relative to aforesaid posts 75 and 7-6, respectively.

Referring once again to FIG. 3, it will be observed that the plastic hose 104 tightly embraces a nipple 117 threadedly secured into the horizontal aperture 68 in valve block 27 and extends therefrom to a receptacle 105 containing fresh blood. A nipple 116 secured within the horizontal aperture 67 in the valve block 27 is connected by means of a plastic hose 106 with the integral nipple 93 positioned in the bottom plate of bottle 89. In the third of this series of openings in the valve block 27 there is a nipple 115 threadedly arranged in the aperture 66 and is adapted to receive a plastic hose 107 which extends to the integral nipple provided at the bottom plate 91 of plastic bottle 88. In the last of the series of four apertures a nipple 114 secured within the aperture 65 of the valve block 27 supports a hose or plastic tubing 108 which extends to the receptacle 109 for collecting the infants old blood. A nipple 92 integral with bottom plate 90 of bottle 89 and a nipple 95 integral with bottom plate 91 of bottle 88 are interconnected by means of legs 110 and 111 of a Y tubing 112.

Although it is believed that the operation of the device under consideration will be apparent to those skilled in the art, a complete cycle of operation now will be described with particular reference to FIGS. 6 and 7.

Operation FIG. 6 depicts the moment when the working apparatus is at substantially the medial point of the suction stroke. Therefore, it will be appreciated that at the beginning of the suction stroke pivot pin 13 carrying connecting arm 12 and pivot pin 17 carrying connecting arm 16 have just passed their lower-most position. At this point cam follower 35 is at approximately the beginning of the large radius of cam 34- secured to spur gear 10. Throughout the entire suction stroke cam follower 35 will engage the uniform large diameter portion of the cam 34 and consequently the rocker arm 41 will remain fixed in a substantially perpendicular plane and will thus project valve spool 46 to the left in its bore 47 so that the annular groove 50 thereof will register with vertical port 59. Further, from an examination of FIG. 6 it will be noted that the annular groove 52 of valve spool 46 also will be in registration with vertical port 57 beneath the area of cylinder 25. When valve spool 46 is in this position there is a free and unobstructed circulation permitted between vertical port 59 and the chamber thereabove provided by the cylinder Wall and lower surface of the piston 19. Of course, this is also true insofar as the chamber above the vertical port 57 that is provided by cylinder 25 and its piston 25 is concerned.

As the spur gears 10 and 11 rotate, the pivot pins 13 and 17 (FIG. 1) lift the connecting

rods

12 and 16 and their associated

pistons

15 and 19 and thereby perform the suction action. Due to the suction stroke of piston 19 the fresh blood is drawn from a receptacle (FIG. 6) and enters into cylinder 26 through the plastic tubing 104 and vertical port 59. Due to the sucking action of piston 15, the infants blood is drawn from bottle 88 and enters into cylinder 25 through aperture 94, plastic tubing 107, aperture 66 and vertical port 57. Simultaneously blood is drawn from the infant through catheter 11 3 into bottle 88. The blood extracted from the infant will now flow into bottle 88 through catheter 113 by the leg 111 of the Y tubing 112 and aperture 95. The suction stroke ends as the

pistons

15 and 19 reach their uppermost positions in cylinders 25 and 2.6. At the uppermost position of

pistons

15 and 19 the cam follower 35 arrives at the end of the large radius portion of cam 34 carried on spur gear 10. As pivot pin 13 of spur gear and pivot pin 17 of spur gear 11 pass their uppermost position, the cam follower 35 will now move down to and become engaged with the smaller radius of cam '34 thereby causing rocker arm 41 to oscillate about pivot pin 42. As this action takes place, the rocker arm 41 will thus reciprocate the valve spool 46 into the new secondary position heretofore described. Up to this point the valve spool 46 has been held immovable relative to the valve block 27 during the entire pressure stroke of the pistons and 19 due to the uniform curvature of the small radius of cam 34. Now that the valve spool 46 has been repositioned groove 51 thereof will be in registration with vertical port 58 as will aperture 67 and groove 53 will be in registration with vertical port 56 as well as aperture 65. In this position of valve 46, it will be observed from FIG. 7 that an unobstructed communication is provided between the cylinder and receptacle 10 9 on the one hand, and between cylinder 26 and bottle 89 on the other hand (note arrows). The related positions and operation of valve spool 46 and its cooperation with the respective grooves will be readily understood froma study of FIGS. 6 and 7.

As spur gears 11} and 11 proceed to rotate as previously described, pivot pins 13 and 17 thrust downward in unison on connecting

rods

12 and 16 and thereby cause pistons 15 and 19' to descend and perform a compressing action. FIG. 7 illustrates substantially the moment when the improved apparatus is at the middle of the pressure stroke. Due to the compressing action of piston 19,, the fresh b ank blood, now contained in cylinder 26, is forced down through the tubing 106 through the bottle 89 into the blood vessel of the infant by way of the leg 110 of the tubing and catheter 113. Simultaneously therewith, and this too may be noted from an examination of FIG. 7, due to the compressing action of the piston 15 the old blood then contained in cylinder 25 is forced therefrom into a waste receptacle 16 9 by way of the tubing 1% (note arrow). The pressure stroke thus ends as

pistons

15 and 19 reach their lowermost extent of reciprocation in

cylinders

25 and 2 6. As the pistons attain this position, cam follower then comes into contact with the small radius portion of cam 3 When this position is reached, pivot pin 13 of spur gear 11) and pivot pin 17 of spur gear 11 will pass their lowest positions and the cam follower 35 begins its approach to ascend to the large radius portion of cam 34 thereby causing rocker arm 41 to oscillate about pivot pin 42. As will now be appreciated, the rocker arm 41 will reciprocate valve spool 46 back to its initial position and a new suction stroke is ready to begin. a

As it is now apparent from the preceding description of operation of the improved apparatus, blood is drawn from the infant through a catheter during the suction stroke of the transfusion device, while new blood is injected through the same catheter during the pressure stroke. It also will be understood that with the exception of catheter 113, no other parts of the apparatus come into contact with both the old as well as the new blood. Thus, piston 19 handles only the new fresh blood during its entire operation, whereas piston 15 during both the suction and the pressure stroke comes into contact only with the old blood of the infant.

It will be obvious to those skilled in the art that before the blood exchange operation can be undertaken, special care should be given to the removal of all air particles from the plastic tubing. This can be easily achieved by running the apparatus through several cycles without inserting the catheter into the vascular system of the infant. During the operation of the apparatus, an air free circulation of the blood is secured by

bottles

88 and 89 which act as air traps. Excessive air pressure in these bottles can be released by manually opening

valves

98 and 99 located in the

covers

96 and 97, respectively.

A simple modification of the device will result in a straight continuous transfusion operation rather than a blood exchange transfusion operation. This can be easily done by shifting pinion 17 180 on open gear 11 and by connecting 65 to blood supply (FIG. 6). By so doing, a continuous flow of bank blood to the catheter is effected.

In operation, blood will be drawn from blood supply 105 alternately in each cylinder. It will be apparent that with the arrangement of elements, valve 46 will operate exactly as previously described. The only change in operation is that there is alternating pumping action where there was previously synchronous pumping action.

In view of the above description and mode of operation of the apparatus, it is thought to be apparent that the improved device can be easily and quickly disassembled for the purpose of replacing the disposable elements thereof as well as cleaning and sterilization of the per manent parts.

Those skilled in the art will readily visualize substitution of elements that may be made in the apparatus described herein and still be able to practice the system disclosed. For example, although pistons and cylinders are shown in the drawings as forming the means for transferring blood to and from the patient, other means are contemplated to be with-in the scope of the invention, such as bellows. As a preferred embodiment, the specification and drawings disclose drive means comprising intermeshing gears, and for this a well-balanced pulley system could be substituted. Accordingly, these and many other changes and modifications are considered to be within the principle of the invention and the scope of the following claims.

' I claim:

1. A unitary system for blood exchange transfusion for patients including a pump and valve chambers and wherein replacement blood is effectively substituted for the blood withdrawn from the patient, comprising storage means for replacement blood, disposal mean-s for the withdrawn blood and catheter means for communicating with the blood stream of the patient in which each of said means are interconnected by means of fluid passageways and said fluid passageways also are connected to said pump and valve chambers, a power source, continuously rotatable drive means driven from said power source, cylinder means defining a first chamber and a second chamber, piston means slidably mounted in said chambers, means extending from said drive means to said piston means for imparting a simultaneous reciproeating motion thereto consisting of continuous suction strokes and pressure strokes, axially slidable valve means positioned beneath said chambers, means extending from said drive means .to said valve means for axially shifting said valve means into a first position at the beginning of each suction stroke to provide unobstructed passageways between said first chamber and said storage means and between said second chamber and said catheter means and for axially shifting said valve means into a second position at the beginning of each pressure stroke to provide unobstructed passageways between said first chamber and said catheter means and between said second chamber and said disposal means.

2. A unitary system for blood exchange transfusion for patients including a pump and valve chambers and wherein replacement blood is effectively substituted for the blood withdrawn from the patient, comprising storage means for replacement blood, disposal means for the withdrawn blood and catheter means for communicating with the blood stream of the patient in which each of said means are interconnected by means of fluid passageways and said fluid passageways also are connected to said pump and valve chambers, a power source, continuously rotatable drive means driven from said power source, a [first pump and a second pump in juxtaposed relation each having a cylinder providing a pump chamher and a piston slidably mounted therein, means extending from said drive means to said pistons for imparting a simultaneous reciprocating motion thereto consisting of alternating suction strokes and pressure strokes, axially slidable valve means positioned beneath said chambers, means extending from said drive means to said valve means for axially shifting said valve meansinto a first position at the beginning of each suction stroke to provide unobstructed passageways between said first pump chamber and said storage means, and between said second pump chamber and said catheter means and for axially shi-fting said valve means into a second position at the beginning of each pressure stroke to provide unobstructed passageways between said first pump chamber and said catheter means and between said second pump chamber and said disposal means.

3. A unitary system for blood exchange transfusion for patients including a pump and valve chambers and wherein replacement blood is effectively substituted for the blood withdrawn from the patient, comprising a container for replacement blood, a container for withdrawn blood and a catheter means for communicating with the blood stream of the patient in which each of said means are interconnected by means of fluid passageways and said fluid passageways also are connected to said pump and valve chambers, a power source, continuously rotatable drive means driven from said power source, a first pump and a second pump in juxtaposed relation each having a. cylinder providing a pump chamber and a piston slidably mounted therein, means extending from said drive means to said pistons for imparting a simultaneous reciprocating motion thereto consisting of alternating suction strokes and pressure strokes, a valve block fixedly positioned beneath and incommunication with said chambers and having a bore extending longitudinally therein, mean-s defining inlets and outlets in said valve block, a reciprocable valve spool in said bore and provided with a plurality of axially spaced annular grooves, means extending from said drive means to said valve spool to shift said valve spool axially in said bore into a first position at the beginning of each suction stroke for aligning the grooves thereof so that they provide unobstructed passageways through said inlets and outlets between said first pump chamber and said container of replacement blood and between said second pump chamber and said catheter and to shift said valve spool axially in said bore into a second position at the beginning of each pressure stroke for aligning other grooves on said valve spool with other inlets and outlets to provide unobstructed passageways between said first pump chamber and said catheter and between said second pump chamber and said receptacle for withdrawn blood.

4. A unitary system for blood exchange transfusion for patients including apump and valve chambers and wherein replacement blood is effectively substituted for the blood withdrawn from the patient, comprising a container for replacement blood, a container for Withdrawn blood, and a catheter means for communicating with the blood stream of the patient in which each of said means are interconnected by means of fluid passageways and said fluid passageways also are connected to said pump and valve chambers, a power source, a pair of rotatable spur gears driven by said power source, a first pump and a second pump in juxtaposed relation each having a cylinder providing a pump chamber and a piston slidably mounted therein, a pair of connecting rods in driving relation with said spur gears and operatively connected to said pistons for imparting a simultaneous reciprocatory motion thereto consisting of alternating suction strokes and pressure strokes, a valve block fixedly positioned beneath and in communication with said chambers, said valve block having a bore extending longitudinally therein, means defining inlets and outlets in said valve block adapted to permit communication between said first chamber and said bore, other means defining inlets andoutlets in said valve block adapted to permit communication between said second chamber and said bore, a reciprocable valve spool in said bore provided with a plurality of axially spaced annular grooves, cam means associated with one of said spur gears, a rocker arm driven by said cam means with the oscillatory free end thereof being connected to said valve spool to shift said valve spool axially in said bore into a first position at the beginning of each suction stroke for aligning the grooves thereof so that they provide unobstructed passageways through said inlets and outlets between said first pump chamber and said container of replacement blood and between said second pump chamber and said catheter and to shift said valve spool axially in said bore into a second position at the beginning of each pressure stroke [for aligning other grooves on said valve spool with other inlets and outlets to provide unobstructed passageways between said first pump chamber and said catheter and between said second pump chamber and said receptacle for withdrawn blood.

5. A unitary system for blood exchange transfusion as described in claim 1, wherein the power source and appurtenances associated therewith are enclosed within a housing provided with suspension means to support the same.

6. A unitary system for blood exchange transfusion as described in claim 5, wherein a divider Wall is interposed between the power source and the continuously rotatable drive means.

7. A unitary system for blood exchange transfusion as described in claim 5, wherein means for venting the system prior to utilization thereof is associated with the replacement blood supply and the shiftable valve means.

8. A unitary system for blood exchange transfusion as described in claim 6, wherein the drive means for actuating said piston means extends through said divider wall and is pivotally supported thereby.

9. A unitary system for blood exchange transfusion as described in claim 6, wherein the cylinder means defining the first chamber and the second chamber are removably secured to said divider wall.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

1. A UNITARY SYSTEM FOR BLOOD EXCHANGE TRANSFUSION FOR PATIENTS INCLUDING A PUMP AND VALVE CHAMBERS AND WHEREIN REPLACEMENT BLOOD IS EFFECTIVELY SUBSTITUTED FOR THE BLOOD WITHDRAWN FROM THE PATIENT, COMPRISING STORAGE MEANS FOR REPLACEMENT BLOOD, DISPOSAL MEANS FOR THE WITHDRAWN BLOOD AND CATHETER MEANS FOR COMMUNICATING WITH THE BLOOD STREAM OF THE PATIENT IN WHICH EACH OF SAID MEANS ARE INTERCONNECTED BY MEANS OF FLUID PASSAGEWAYS AND SAID FLUID PASSAGEWAYS ALSO ARE CONNECTED TO SAID PUMP AND VALVE CHAMBERS, A POWER SOURCE, CONTINUOUSLY ROTATABLE DRIVE MEANS DRIVEN FROM SAID POWER SOURCE, CYLINDER MEANS DEFINING A FIRST CHAMBER AND A SECOND CHAMBER, PISTON MEANS SLIDABLY MOUNTED IN SAID CHAMBERS, MEANS EXTENDNG FROM SAID DRIVE MEANS TO SAID PISTON MEANS FOR IMPARTING A SIMULTANEOUS RECIPROCATING MOTION THERETO CONSISTING OF CONTINUOUS SUCTION STROKES AND PRESSURE STROKES, AXIALLY VALVE MEANS