US 3078847 A
Description (OCR text may contain errors)
1963 F. A. WANDELL ETAL 3,078,847
BLOOD HANDLING METHOD AND APPARATUS Filed May 6, 1959 INVENTORS FRANCIS A. WANDELL EDWARD J. POITRAS M Bun 1t M.
+ tun-M ATTORNEYS United States BLOOD HANDLENG METHQD AND APPARATUd Francis A. Wandcli, Hepkinton, and Edward J. Patti-as,
Holliston, Mass, assignors, by mesne assignments, to
Baxter Laboratories, Inc, Morton Grove, Iii, a corporation of Delaware Filed May 6, 1959, Ser. No. 811,?35 Claims. (Cl. 123-214) This invention relates to selective preservation and use of human whole blood and its components, and more particularly to method and means for sequentially and differentially admixing the blood and components with desired preservative solutions. The invention improves the practice of blood component therapy, and more particularly affords flexible handling and efficient use of the blood for such therapy and in safe and preservative manner.
The invention will be better understood from a consideration of the following specification, taken in conjunction with the accompanying drawing, in which:
The FIGURE presents an assembly view of an exemplary apparatus of and for practicing the invention.
Blood is a complex liquid having a number of components of clinically proven value. Thus in a particular therapy the indicated need may be for a specific one of such components as the plasma, the red cells, the platelets, or the leucocytes of the blood. in blood component therapy as herein contemplated, then, the indication for transfusion is based on the need for the special function of a particular component of the blood.
For example, separated or packed red cells may be used in cases such as chronic anemia requiring restoration of a diminished oxygen carrying capacity, and in which the administration of the whole blood would involve the hazard of overloading the circulation. In hemophilia cases the use of fresh or fresh-frozen plasma is indicated, for its labile clotting factors. For burn victims, and other shock cases requiring the restoration of blood volume, liquid or frozen plasma is separately employed. And as a hemostatic measure or for the control of excessive hemorrhage as in cases of thrombocytopenia the platelets are specially called for, and may be administered as platelet-bearing plasma or, when the administration of a small fluid volume is necessary, as platelet concentrate.
Of course the massive transfusion of whole blood may also be indicated, as in cases of hemorrhage or shock, or for operations involving extracorporeal circulation, or for exchange transfusions. But in these and other cases the aseptic subdivision of a unit collection may still be called for, as particularly in pediatric practice.
Again, under some circumstances one of the blood components may be toxic to a recipient, and so be required to be isolated prior to transfusion. For example, leucoagglutinin from prior transfusions may call for the removal of the leucocytes from the blood to eliminate their leutoxic potential for the recipient.
This invention supplies the need, for the foregoing and other purposes and applications, for a reliable flexible technique and apparatus more generally for safe collection, sampling, storage, and administration of the blood, and more particularly for better preservation of the blood, for separation of the blood into any and all its components, and for the admixing and administration of the blood or components in preservative and selective manner and without risk of contamination. The invention provides further a completely closed air-free system and a bacteriologically safe technique by which, for example, whole blood may be divided into pediatric doses; plasma may be separated immediately after bleeding for preparation of fresh-frozen plasma and the red cells stored for the full safe or viable period; packed red cells may be prepared without loss of the 3,078,847 Patented Feb. as, less plasma; and platelet concentrate may be prepared irnmediately after bleeding.
Human blood is routinely handled for administration and otherwise by processing through a supply or bank, whereby a suificient volume of the blood or indicated components is maintained without dependence upon the emergency availability of donors of the right type and number. In this indirect transfusion practice the tissue is removed from its protective and supportive environment and placed in an artificial situation, and to prevent it from clotting on collection and deteriorating during storage the blood is commonly collected through or into a preservative medium or solution.
There are various types of blood preservative media, including a number or range of chemical preservative solutions, and the solutions are differentiated in respect to the length of their etficient preservative time, the effect they have on the blood and the cellular elements thereof, and the reaction they induce in the recipient of the blood. And the differing characteristics of the preservative solutions may be conflicting for some purposes and complementary for others.
For example, some solutions are distinguished by their long-term preservative effect; with the use of these the blood may be safely administered after refrigerated storage for up to, say, 21 days. But the collection of blood into long-term preservative or anticoagulant solutions now commonly employed, such as various ACD (acid-citrate-dextrose) formulae, inevitably involves some degree of alteration from the normal functional capacity of the cellular elements, as well as a disturbance of the electrolytic composition of the plasma and denaturization of the labile proteins, particularly those involved in coagulation. These changes are due in large part to the acidity and hypotolicity of the ACD solutions.
The result is that whereas a safe amount or as much as -85% of the red cells of ACD blood may be viable after up to 21 days of storage refrigerated at, say, 4-6" G, the platelets disintegrate rapidly and are made functionally useless after only 24-48 hours of storage, many of the labile plasma proteins are denatured and biologically inactivated, and the plasma becomes so extremely acid as upon administration to impose a heavy burden on the acid-base regulating mechanisms. Thus the use of ACD blood is contraindicated in instances of massive transfusion on account of the risk of citrate intoxication of the recipient.
There are other solutions, such as those of the class exemplified by the solution commercially known as heparin, which are distinguished by their relatively short-term preservative eifect; that is, they have the ability to be efiicient as a preservative only for a term of, say, two or three days. But these short-term preservative solutions do not have the same adverse effect on the blood or recipient as have the long-term solutions, so that the use of blood collected into solutions of the short-term type is indicated for open heart surgery and the like.
Again, the needs peculiar to specific pati-entsfor minimal volume, intact clotting mechanism, low sodium intake, or absence of calcium depletion due to excess citrate may be satisfied by unadulterated ion-exchange blood; blood collected through ion-exchange resin as dis closed in Walter Patent No. 2,702,034 is also used for control of bleeding and for massive transfusions.
Further, when collected in accordance with the preferred practice of this invention, that is, in a closed, colapsible, air-free, hemorepellent-surfaced system, there is provided a protective or preservative environment or medium in which the blood can be kept liquid as such for a period of, say, 4-6 hours without the use of any anticoagulant or other preservative solution.
As above indicated the avoidance of the toxic antiice coagulants, including the citrate radical, is essential for optimum preservation of the formed elements and chemical integrity of the plasma of the blood. Thus and more generally, the quality of the stored blood may be improved, making for more efficient transfusions, and the blood may have wider application, including that to massive transfusion, if the blood has been collected by ionexchange, or into a container having a short-term preservative solution.
But because of postponement of operations or need for less blood than anticipated the use of blood collected in short-term preservative manner may not be and often is not required, within the expected time, in the anticipated amount. Thus in the prior practice significant quantities of blood have gone through the storage period unused, and have had to be thrown away.
All the heretofore wasted short-term blood is saved in accordance with this invention by its combining or admixture following collection with a long-term preservative solution. And there is had a further saving of the blood not used during the safe shelf-life span whether of the short or long term, in that the blood may safely be divided or converted into plasma which can be stored for up to six months or more.
The limiting factor in the safe and effective use of whole blood is the progressive loss of erythrocytes that occurs during refrigerated storage. The maintenance of red cell viability during storage is determined by the severity of cell damage initiated in collection, which damage is aggravated in storage. One of the factors contributing to the inevitable alteration from the normal functional capacity of the cellular elements of stored blood, a destructive phenomenon termed the lesion of collection, is the shock on collection into ACD or other at least initially unfavorable solution, the shock initiating a loss of viability which, as just mentioned, is aggravated in storage. Further, and in such unfavorable preservative medium or solution cases, the lesion of collection is related to the sequence of collection, in that the cell damage factor here concerned is a function of the ratio of the blood and preservative or anticoagulant volumes, the ratio having a significant effect on the rate at which the red cells deteriorate in storage. Thus and more particularly the degree of damage to the red cells on collection into ACD is most severe in the initial phases, due to the aforementioned acidity and hypotoxicity of the ACD, and diminishes as the collection proceeds, due to the buffering action of the plasma proteins and hemoglobin.
Under this invention the quality of blood preserved with ACD or other unfavorable solution is novelly and appreciably improved by providing or controlling the sequence of collection. More particularly the ratio of red cells in solution is made more favorable, and the buffering action of the plasma is more fully utilized, through a component separation prior to the admixture of the blood with the anticoagulant, by which the solution is first diluted or buffered by the plasma.
The blood handling method and means hereof provide in this and other respects for collecting and storing human blood with minimum trauma to the cells and proteins, so that infusions are made more efiiciently, that is, with blood characterized by maximum viability of the cellular elements and by minimum burden on the recipient in respect to the elimination or repair of damaged cells. There are additional mechanical or extracellular factors which contribute significantly to the aforementioned lesion of collection, such as the turbulence and foaming encountered in the collection of blood in vacuum bottles only partially filled with solution; the surface characteristics or wettability of the blood handling apparatus; and the random or other than thorough and uniform mixing of the blood with the solution. In accordance with this invention, the quality of stored blood is improved by the elimination or minimizing also of these additional factors.
In the exemplary form of the drawing, FIG. 1, the invention system or apparatus comprises collecting or storing means having a flexible collapsible chamber or bag It) to which is integrally joined a flexible collecting or donor tube 11 of suitable length. The tube 11 provides and mounts at its outer end a rigid cannula or phlebotomy needle 12 which is specially sharpened to minimize tissue trauma, which is flared at the exit end for laminar flow, and which has a smooth hemorepellent coated bore, all to prevent initiating of chemical clotting, and all as disclosed in Poitras Patent No. 2,638,897 and Walter Patent No. 2,702,037. The needle 12 further has a double tapered hub over one end of which is seized the end of tube 11 and whose other end has expanded over it a rubber of other resilient cover 13 drawn over the cannula of the needle so as to seal the cannula against contamination.
The indicated lay flat construction of the bag 10 may be afforded by juxtaposing sheets or fiatting a large tube initially open at the ends, through one of which the inner end of the collecting tube 11 is received before said one end is flatted and fused therearound as at bar seal 14.
The integral donor tube 11 is closed at its inner end by means located within but removable by manipulation from outside and without entering the system, and herein comprising a hemorepellent-coated steel ball 15 which is oversized, and so frictionally held in the tube.
Also sealed through the end 14 of the storage bag 10 is a port assembly 16 which may be like that of the copending application of David Bellamy, Jr., Serial No. 412,549, filed February 25, 1954, now Patent 2,894,510 issued July 14, 1959, and so comprise a short tubing length 17 passed between and having a part projecting from the seal 14, and interiorly closed by a partible diaphragm 18 which is positioned for puncturing by a coupler or rigid cannula inserted in the tube end. A pair of sheet strips 19 also received through the bag end are sealed to define a pouch and sterile zone around the projecting tube part, and terminate in divergent tab portions 19a by which the strips may be grasped or pulled apart to expose the tube end for such cannula insertion without touching or contaminating the bag outlet.
The invention system or apparatus further comprises a transfer or storing means having a second flexible collapsible chamber or bag 20 shown as formed similarly as the first bag 10, and which is integrally joined thereto by a connecting tube 21 of suitable length. In accordance with the invention, tube 21 is removably closed adacent bag 10 by externally manipulable means such as an oversized hemorepellent bead 22, and means such as the wedge slotted metal clip 23 are additionally provrded for removably closing and also adjustably regulatmg the flow through the tube 21, again by manipulation from without and without entering the fluid system.
The tube 21 opens into bag 20 through fiat end seal 24, through which are received also a pair of port assemblies 25, 29 comprising tubing lengths 26, 30 interiorly closed by partible diaphragms 27, 31 and cxteriorly sealed by the sheet strips 28, 32, which strips may be manipulated to break the outer port seals by grasping and pulling apart their tab portions 28a, 32a.
The described bag and tube apparatus will be understood to be constructed and prepared in accordance with the teaching of the aforesaid Walter Patent No. 2,702,034, and more particularly by integral fabrication from polyvinyl chloride or the like flexible elastic plastic material WhlCh is also tough and transparent and presents to the blood only glossy inert hemorepellent surfaces such as help delay coagulation and degradation of the blood. As above indicated, the needle 12 and valve beads 15, 22 are also coated in their blood contacting parts with a hemorepellent film, whereby the apparatus is characterized in its entirety by non-wetting walls such as prevent or reduce to a negligible level the sludging of the blood cells 53 in storage, and such as improve the plasma in terms of potassium and hemoglobin levels.
The apparatus hereof is further distinguished by laminar flow promoting passages minimizing mechanical trauma and by flexible collapsible chambers from which excess air may be eliminated, the same minimizing frothing and turbulence of the blood in collection and preventing platelet aggregation, and also permitting uniform mixing of the blood and preservative solution. The elimination of the air-blood interface will be understood also to preclude any risk of air embolism on administration of the blood.
And in that the bags and tubes may be divided by fiatting and fusing and the tubes segmented also by knotting or clipping the apparatus is still further distinguished as presenting volumes or chambers which may be separated or divided and between which connection may be established and re-established by manipulation from without and without entry to the iiuid system, whereby one or more components or samples of the blood may be separated or combined, or drawn oii or administered, safely, that is, without disturbing or risking contamination of the residual collection.
in manufacture and preparation for use the apparatus is rinsed or otherwise treated to render it pyrogen-free, and the bags 10, 20 are charged with the desired preservative solution or solutions, evacuated or" excess air, and assembled and integrally joined in the indicated relation and as closed at their respective inl t tubes 11, 21 by the beads 15, 22. The assembly is then sealed, by installing the needle 12. and cover 13, and sterilized in medically accepted manner.
In one mode of practicing the invention the bag in, which may be sized for an adult donation of, say 560 ml. is charged with an appropriate, say, 30 ml. volume of a short-term anticoagulant, say, heparin. The second bag 2i which may be of a size to receive at least a component of the blood is charged with a suitable, say, 75 ml. volume of a long-term anticoagulant, say, ACD.
For collection of the blood the needle cover 13 is removed, venipuncture is performed, and the bead 14 is worked or milked down into the bag to permit blood flow, during which the bag is kneaded or otherwise agitated for the desired mixing of the blood with the preservative solution. If it is desired to use whole blood, and if there is occasion for it within the preservative time of the short-term medium or solution, the bag 29 and its contained solution will be ignored or remain sealed off from the bag iii, and the administration of the blood will be carried out by manipulating the port assembly 16 as described in the aforementioned Bellamy application for sterile coupling to a recipient or blood administering set.
But where for any reason the blood is not used in time, it may at the appropriate interval after collection, and without violating the sterility seal of the system, be combined or admixed with the long-term preservative solution. As earlier noted, this admixture subsequent to collection may be accomplished in a manner which reduces the trauma of collection and so yields blood of markedly better quality than if it had been collected directly into ACD.
Thus in the preferred practice the blood in bag 10 is first centrifuged or allowed by gravity sedimenting of the cells to separate the plasma in a supranatent layer with the bag held inlet-outlet end up as shown. Next the sad 22 is worked down into bag 10 and the bag compressed or squeezed to express some or all of the plasma into bag 2%. The bag 20 is then temporarily closed ofi, as by pinching tube 21 with the clip 23, and manipulated to mix the ACD and plasma. The tube 21 is then reopened and one of the bags 1d, 20 is squeezed for the desired admixture of the plasma-diluted ACD with the cellular elements of the blood in the other of said bags, which latter is kneaded or otherwise manipulated for the desired uniform mixing of the cells and solution.
The blood is now available for use at any time during the long-term preservative period, and it may be sealed, as for storage before use, if in bag 29 by fusing or clipping connecting tube 21, and if in bag 10 by thus closing tube 21 and by fusing, clipping or knotting also collecting tube 11.
The invention practice as just described will be understood to comprehend more than the mere short-term: long-term option. Initially it affords the collection of blood which is as nearly as possible an unadulterated undistorted tissue and free from adverse effects on the recipient of the blood; and in this the short-term or specially preserved blood may be collected by ion-exchange or in a closed air-free hemorepellent system containing no preservative solution, as well as by admixture with heparin or other short-term preservative solution as in the above described example.
The further advantage of the indicated mode of invention practice is that the blood may, by admixture subsequent to collection upon or at any time before expiration of the short-term preservative time, be saved and held for the long-term preservative time.
The still further benefit to be realized from the particular application of the invention here concerned is the production of ACD or other long-term preserved blood of distinctly better quality. It will be appreciated in this connection that the providing or controlling of the sequence of collection renders suitable for component therapy all those long-term preservative solutions which, while desirable or superior in one or more preservative respects have heretofore been or would otherwise be precluded for such use, because of their deleterious effects on one fraction when not buffered by another component of the blood.
It will be understood also that in this short-term; long-term preservation technique many combinations of the primary or short-term and secondary or long-term preservative medium or solution may be employed, and that there are many available combinations also in respect to the mixture of the secondary solution with one or another fraction of the blood. Stated more generally, the technique provides for admixture of the whole or selected fractions of the blood with one or more primary and secondary preservative or anti-coagulant volumes or solutions, in any desired combination and order of mixing. Again, in the component therapy practice hereof and by separate or delayed admixture following collection of the blood various anticoagulant or other conditioning or preservative media or solutions are combined 'with the blood or components in any desired sequence, or may be combined with one or more components in preference to or to precede the combination with one or more other components or with the residue of the blood.
Those skilled in the art will recognize f-urtherthat there are numerous other modes and advantages of the practice of blood component therapy and the aforesaid and other manipulations, separations and admixtures in accordance with the invention. These further modes of invention practice afiord for example the blood or com ponent manipulations or separations as heretofore particularly mentioned. Thus the platelets are enabled to be separated and used with preservation for use also of the residue of the collection, upon recombining with the plasma, as a standard blood. Again, a donation may be manipulated to eliminate a toxic component such as otherwise precluding administration of the blood, to a particular patient.
The earlier mentioned white cell or leucocyte example will serve to further illustrate the versatile blood and component separation and admixture under the invention. To remove the leucocytes the blood is spun or centrifuged following collection, as in bag 10, to
separate the plasma and buffy coat (leucocytes and platelets) which are then expressed, as to bag 20, and admixed as desired. The apparatus is then spun again to separate the plasma and buify coat, in bag 20, and the plasma is expressed back to and recombined with the red cells, in bag 10. Thus and on reclosing tube 21 the leucocytes and platelets are isolated in bag 20, and a non-toxic blood is available in bag 10.
This invention will be understood importantly to gain also the maximum use of the blood, in the ways already mentioned and in the further respect of much more frequent bleeding of donors. Thus where it is desired to administer or otherwise employ only the plasma of the blood, and the red cells are to be returned to the donor, this may be done much more frequently than the taking of the whole blood, due to the regeneration of the plasma at a far more rapid rate than of the red cells.
It should here be noted that under the invention the above stated separation, and also the other blood or component manipulations involving return of some or all of a donation or fraction thereof to the donor, may be performed with the apparatus held closed and the needle 12 sealed by retention of the tube fitted needle in the arm of the donor.
Blood handling is improved by this invention in respect also to the admixture of the blood or components with conditioning solutions such as of the nutrient type, and which may be variously admixed with the blood or first with a separated buffering component, as in the collecting means or bag or by expressing the nutrient solution from the transfer means or bag. The blood thus fortified may, as just noted, be returned to the donor, or it may be otherwise employed or administered.
And as hereinbefore pointed out, the convenient isolation of the components for specific therapy may also be carried out hereunder without the use of any adultering preservative medium or solution, as where the components are for fresh use and are isolated for administration or other delivery in and from a closed air-free hemorepellent system hereof.
Those skilled in the art will appreciate that still other therapy manipulations and particular blood-preservative or component-solution admixtures and sequences of admixtures are or will be known or preferred by the art.
From the foregoing it will be understood that this invention provides in part for the differential admixing following collection of the whole blood or of selected components with one or more preferred preservative or other conditioning media or solutions, and in any desired sequence of steps. Again, the delayed or subsequent admixture hereunder may be to selectively combine a solution with one component in preference to or preceding the admixture of that solution with another component of the blood.
Our invention is not limited to the particular embodiments thereof illustrated and described herein, and we set forth its scope in our following claims.
1. The method of handling blood with an integral closed collapsible sterile sealed pyrogen-free hemorepellent system having a collecting means and a transfer means which comprises charging the collecting means with a short term anticoagulant selected from the class having negligible adverse effect on the blood or recipient, charging the transfer means with a long term blood preservative, closing between the collecting means and the transfer means, obtaining the blood in said collecting means and for administering from that means during the short term, and upon expiry of the short term opening between the collecting means and said transfer means and admixing the blood and long term preservative.
2. The method of handling blood as recited in claim 1, wherein the collecting means is charged with a heparin an ACD solution.
3. The method of handling blood with an integral closed collapsible sterile sealed pyrogen-free hemorepellent system having a collecting means and a transfer means which comprises conditioning the collecting means for unadulterated short term preservation of the blood, charging the transfer means with a long term blood preservative, closing between the collecting means and the transfer means, obtaining the blood in said collecting means and for administering from that means during the short term, and upon expiry of the short term opening between the collecting means and said transfer means and admixing the blood and long term preservative.
4. The method of handling blood with an integral closed collapsible sterile sealed pyrogen-free hemorepellent system having a plurality of blood storing chambers which comprises conditioning the system for preservative collection of and with negligible adverse effect on the blood in a first said chamber, charging a second said chamber with a long term blood preservative, closing between said first and second chambers, collecting the blood into said first chamber in preservative manner, manipulating the first said chamber and the blood collected therein to isolate a buffering fraction of the blood, opening be tween said first and second chambers, admixing said buffering fraction with said long term preservative, and then admixing the combined fraction and long term preservative with the residue of the blood.
5. The method of handling blood as recited in claim 4, wherein the long term preservative is ACD and the buffering fraction is the plasma of the blood.
6. The method of handling blood with an integral closed collapsible sterile sealed pyrogen-free hemorepellent system having a plurality of blood storing chambers which comprises conditioning one said chamber with a primary medium for preservative storage of at least a fraction of the blood, conditioning another said chamber with a secondary medium for preservative storage of at least a fraction of the blood, initially closing between said one and other chamber, collecting the blood into one said chamber, closing the inlet to that chamber, and subsequently opening between the chambers and combining at least a fraction of the blood in the one with the preservative medium in the other of said blood storing chambers.
7. The method of handling blood with a plurality of flexible collapsible chambers integrally connected in a closed sterile sealed hemorepellent system which comprises initially charging one of the chambers with a selected long term anti-coagulant preservative, evacuating and sealing the chamber, collecting and storing the blood in another of said chambers in preservative man: ner, and subsequently opening between said other and said one chamber and manipulating the system to adrnix at least a component of the blood with said selected long term anti-coagulant preservative.
8. In the practice of blood component therapy with apparatus providing an integral flexible plastic hemorepellent system having a plurality of collapsible blood storing chambers and providing means manipulable from without said system to close and open between said chambers, the steps of providing at least one chamber of said system with means for conditioning at least a component of the blood, evacuating the apparatus to collapse said blood storing chambers, manipulating said close and open means to close between said chambers, sealing and sterilizing said hemorepellent system, collecting a blood donation into a chamber of said system in blood preserving manner, and then, following that collecting, opening between and expressing from said chambers sequentially to admix at least a component of the blood with said conditioning means.
9. For the practice of blood component therapy method providing both collection with minimum adverse effect and storage for the maximum term of the blood, an integral flexible plastic blood handling system, said system sterile sealed and pyrogen free and presenting only hemorepellent surfaces to the blood, a plurality of collapsible blood storing chambers in said system, tubing connecting the chambers of said system, means associated with and manipulable from Without said system for opening and closing between said chambers, port means on said chambers and adapting them for sterile administration of the blood, means in one of said collapsible blood storing chambers conditioning it for preservative handling of the blood With negligible adverse effect, tubing inletting 1% 2,847,007 Fox Aug. 12, 1958 2,848,995 Ryan Aug. 26, 1958 2,876,769 Cordova Mar. 10, 1959 OTHER REFERENCES Walter et al.: A Closed Gravity Technique for the Preservation of Whole Blood in ACD Solution Utilizing Plastic Equipment, Surgery, Gynecology and Obstetrics, volume 94, No. 6, June 1952, pages 687-692.
to said one chamber and adapted for connection to a 10 surgenoli Scientific American, Volume blood supply, and means in another of said collapsible 2, Pages 5462, February 1954- (Available i blood storing chambers conditioning it for anti-coagulant ence Llbraflh) preservation of the blood tor the long term, Earl et al.: A Practical Method for the Aseptic Prepa- 10, Th apparatus f l i 9 h i id means ration of Human Platelet Concentrates Without Loss of ditioning said one collapsible blood storing chamber for 15 other Blood Elements," New Enlalld JOUI- of preservation of the blood with negligible adverse effect 1132-1133, June 14, is a heparin solution, and wherein said means condition- Buttn et Vltfo Oxygenatlofl of Fresh lOOd ing said other collapsible blood storing chamber for for Arteflal Perfusion, AMA Archives of y, preservation of the blood for the long term is an ACD 75, August 1957, Pages l ti 20 Klein et al.: Simple Methods for the Aseptic Separation of Blood Components, Bibliotheca Haematologica References Cited in the file of this patent (Basel), volume 7, January 20, 1958, pages 382-385.
(Copy in Division 55.) UNIPFED STATES PATENTS Mcllvanie: Glass vs. Plastic Containers for Platelet 2678159 E1115 May 1954 25 Transfusion, Bibliotheca Haematogica, (Ba el), v 1, 7, 2,702,034 Walter 15, 1955 January 20, 1958, pages 481-490, 2,822,315 Cohn Ffib. 4, 1958