CA2064757A1

CA2064757A1 - Blood component needle assembly for reduced coagulation response

Info

Publication number: CA2064757A1
Application number: CA 2064757
Authority: CA
Inventors: Grant S. Benjamin; Brian Ritchey; Donald W. Schoendorfer
Original assignee: Individual
Current assignee: Baxter International Inc
Priority date: 1990-06-14
Filing date: 1991-06-12
Publication date: 1991-12-15
Also published as: AU647151B2; WO1991019522A1; AU8051591A; JPH05500768A; EP0487685A4; EP0487685A1

Abstract

A needle assembly (60) is provided for withdrawing and returning blood and blood components to a patient or other donor, especially in a machine-assisted blood component separating operation, whereby the incidence of clotting and the size of clots formed in the needle is greatly minimized. The needle assembly is especially useful in situations where only low levels of anticoagulant are added to the extracorporeal blood, which, but for the improved needle assembly, would exacerbate the problem of clot formation at the needle. The assembly (60) includes attached tubing (66) having an internal diameter adjacent the blunt end (72) of the needle (68) that is equal to, or preferably less than, the internal diameter of the needle.

Description

WO 91/19S22 ~ L 7 ~ ~ P~T/U~;91/04191 FIELD OF THE INvENT~
.
The present lnventlon relates to an ~mproved needle assembly and more particularly to a needle assembly for tr~nsferrtng blood components, lncluding pa~ked red cells or o~her plasma-depleted blood, wlthout an occlusion ln the needle asse~bly.

B~C~GROUND OF ~HE INVENTION

There exlst var10us pump-ass~sted systems for ~lthdrawlng blood from a pat1ent or other donor, separatlng the blood lnto one w ~ore blood fractlons, and returnlng one or more fraetlons to the donor.
Typlcally, these syst-ems lnclude an 1nstrument havtn~ varlous pumps, clamps and control clrcultry, ~nd a dlsposable set hav1ng plastic : ~ ~ tub~ng for ~luld f10~ and a separatlon d~vlce. The set ls mvunted : on the instrument.
S~me of these systems are two needle syst~ms. One neetlle may be 2~ 1nserted ln a donor'~ venous system at one arm and the other needle may be 1nserted ln the donor's venous system at the other arm. One : : nee~le ls an 1nlet:needle for wlthdra~in~ blood from the donor. The other needle ls a return needle, for returnlng blo~d fractions to : the donor. :An example of such a sys~em 15 the CS-3000~ B~ood Cell Sepa~rator sold by~ Baxter Healtheare Corporatl~n o~ Deer~leld, nols, a wholly o~ned subsidiary of the asslgnee o~ the present 1nvent~on.
Other blood separation systems utlll2e ~ slngle needle ~hich ; serves to alternate1y w~thdraw and return blood. An example o~ such WO 91/19522 ,~, 3 ~ a ~ PCI/US91/04191 a system ls the Autopheresls-C~ devlce sold by Baxter Healthcare Corporatlon.
The Autopheresls-C system ~s dlsclos~d for example in PCT
Internatlonal Publlcatlon No. ~088/05332, Schoendorfer et al.
entltled "Conelnuous Centrlfugatlon System and Method For Dlrectly Derlvlng Intermedlate D~nsi~y Materlal From a Suspenslon"; Canadian Patent No. 1,261,765, Schoendorfer, entltled "Method and Apparatus For Separat~on of Ma~ter From Suspenslon"; and ln U.S. Patent No.
4,851,126, Schoendorfer, entltled "Apparatus and Methods For Generatlng Platelet Concentrate".
A problem ~hlch occurs from tlme to tlme 1n these and all other blood separat~on systems ls clott~ng ~tthln the se~, typically adjacent to or ln the needle assembly. In two needle systems, such clott~ng ls more llkely to occur at the return needle than at the blood wlthdrawal needle.
The clotting problem ~s most llkely to occur wlth blood fractlons returned to the donor from a separatlon chamber ln the set, For reasons not entlrely kno~n at thls tlme, the shear stresses created 1n the separators, ~hether utll1z~ng pr~nclples of centr~fugat~on, flltrat~on, Taylor vortlces, e~c. are suff1clent to at 1east partlally actlvate the platelet component of blGod.
Dependlng on the spec1f1c separatlon procedure, some or mos~ of these activated platelets are returned W~th the packed cells to the donor, 1ncreaslng the l~kelthood for coagulat~on, desptte the add~t~on of ant1coagulant to the extracorporeal blood.
Recently, lt has been found des~rable to reduce the amount of antlcoagulant added to blood ln automated blood separation procedures, such as disclosed ~n U.S. Patent Appllcat~on Serial No. _ , entltled "Automated Blood Component Separatlon Procedure Promotlng Functlonal Charactertst~es ~n Multiple Blood : ~ : Components", Yean Yow Hwang et al. and U.S. Patent Appl~eat~on Ser1al No. _ , entltled "Method and Apparatus for Adminlstrat~on of Ant~coagulant to Red Cell Suspens~on Outpu~ of a : Blood Separator", Donald W. Schoendorfer, both f~led concurrentlY
. ~ ..

. :,,.
.
,:' , w o 91/19522 pcT/usslto419l 2 ~ 7 herewlth and asslgned to the asslgnee of the presen~ lnvent~on.
The reduced level of antlcoagulant tends to exacerbate the problem of coagulation near the needle assembly ln blood components be~ng returned to the donor. It ~ould be des1rable to provlde a needle assembly ~hlch lessens the llkel~hood of coagulation. It would be desirable to provide a needle assembly that ls espec~ally resistant to coagulation durtng return flow of packed cells through the needle to the donor.

SU~MARY OF THE INVENTION

The present invention 15 dlrected to a needle assembly that 15 resistant to occlusion by reducing the llkellhood of blood component coagulation thereln. The needle assembly of the present lnvention ls especlally deslrable for use in automated blood component separatlon systems, especially but not llmlted to those systems utlllzlng reduced antlcoagulant levels ~n the blood components, lncluding whole blood, wlthin the set of the system. The present lnventiQn provldes a needle assembly lncludlng a hollow needle w~th a polnted end and an opposlte end; i hub ~ounted about the clrcumference of the needle shank; and hollow, flexible tublng ~ncludlng a proxlmal end mount~d about the needle opposlte end, wherein the tnternal dlameter of the tublng ls no greater than, and preferably less than, the lnternal dlameter of the needle. The needle assembly of the present ~nventlon ls especlally useful for transfer of blood fractlons havlng actlvated platele~s thereln and blood fractlons havlng low antlcoagulant levels. The needle assembly ls especlally useful for returnlng such blood fractions to the donor, although the assembly also ls useful for fac~l~tatlng the draw of whole blood from the donor, by provldlng a substant~ally constant diameter flow path to the anticoagulant contact and mixing area.
~1 .

.

. . ~ . . ~ . .

w o 9~/19522 ~ 7 ~ 7 PCT/U591/04191 BRTEF PES~RIPTIQ~ GF THE-~RAwIN~ BE~

Flgure 1 ls a perspecttve view of the needle assembly of the present invention lnclud~ng needle hub and t:onnectlng tublng and a schematic illustrat~on of a blood separatlon tnstrument separatlon set and ~ha~ber and antlcoagulant source;
Flgure 2 ~s an enlarged fragmen~ary plan vlew ln partial cross-sect~on of the needle assembly lllustrated ln Flgure l;
Figure 3 ls a plan view partlally broken away of a prior art needle assembly;
Figure 4 is a cross-sectional view taken at line 4-4 of Flgure 3 lllvstratlng.a typ~cal clot formatlon; and Figure 5 ~s a plan v~ew part~ally broken away of stlll another prior art needle assembly for blood donatlon.
DETAIL~D q~SCRlPTION OF l~_~BEFERREP ~M~ODIMENT

Referring f~rst to the prlor art there ls lllustrated ln Flgure 3 a prior art needle assembly lO m~de by Terumo Corporat~on of -~
Tokyo Japan. The assembly lO lncludes a hollow needle 12 having a pointed end 14 and blunt end 16. A plastlc hub l8 surrounds the ~-needle shank 12. Plastic ~lngs 20 extend lntegrally from the hub 18. The wings are common on many phlebotomy needles ln order to asslst securlng the needle assembly to the donor and~or to insert the needle lnto the donor s veln.
The needle hub 18 1ncludes a dlstal end 22 that extends beyond the blunt end 16 of the needle. The hub distal end 22 includes a flat end port~on 24 and a tapered portion 26 extending ~nwardly from the flat end portlon 24 to the needle fltting portton 28. It is -.
belleved that the needle fltting portlon 28 is mo1ded and adhesively bonded to the cannula. A small deflned space 30 typically is present between the portion 28 and the needle 12.
'.' ~

' ''' '"':

"j.

WO 91/19~22 PCl`/US9~/041~1 2 ~ 7 Plastic tubing 32 made for example of PVC lncludes a prox~mal erd 34 mounted typlcally ~9th a medlcal grade solvent or adheslve about the hub 18. The solvent ls dlsposed bet~een the outer surface of the hub 18 and the lnterlor sur~ace 36 of ~he tublng 32. ~h~le an 1nterference f1t may be lntended between the tublng 32 and the hub 18, the use of solvent m~nlmlzes the need for such an 1nterference fit.
Figure 4 ~llustrates the lnter~or of the needle assembly lO
after return of packed cells to a donor. A clot 38 ls shown at a typical location wlth~n the needle, at the bl~nt end 16 thereof.
The small space 30 ls present bet~een the needle hub lB and the needle 12, as deflned by the needle ~lttSng port1On 28.
A clot 38 such as shown ln Flgwre 4 1s vlrtually a total occluslon of the needle 12, ~hlth would shut down an automated blood separatlon system.
The reasons for and mechan1sms of clottlng are not entlrely understood. It has been dlscovered however, that clottlng ~s more l~kely to occur durlng return of blood fract~ons to the donor, wh~ch may be the result of a hlgher hematocr~t solut~on dur~ng ~he return of the blood fractlon than durlng the withdrawal of ~hole blood.
Alternat1vely or cumulatlvely, the hlgher 1ncldence of clott1ng during retvrn of blood to the donor may be the result of platelet actlvatlon caused by shear stresses placed on the pl~telets durlng the blood separatlon step, for example. The clot ln the needle assembly may be formed by platelets, f1br1n, flbrln deposlts or by another mechanlsm.
In one example of the prlor art needle as~embly lO ~llustrated ln Flgure 3, a 16 gauge needle ~s used, hav~ng an outer diameter of 0.065 lnch and an lnner diameter of 0.056 lnch. The plastic hub 18 has an ~outer dlameter of 0.140 lnch at a polnt ad~acent the blunt end 16 of the needle 12. The tubing has ~ normal outer d~ameter of 0.220 lnch and normal lnner diameter of O.lZ5 lnch. The tapered portlon 26 def1nes a 60 conlcal shaped surface. ~he ~ub~ng 32 ls w o 91~19522 ~ 7 ~ ~ PCT/US91/04191 stretched about the hub 18 to ~orm the lnterterence fit, enlarglng the lnner and outer diameters frc~ normal. Thle lnternal d1ameter of the ~ub~ng tn the flow path ad~acent the dlsta1 end 22 of the needle hub 18 i5 larger than the lnternal dlameter of the needle.
Referrlng now to Figure 5 there ~s lllustrated yet another prior art needle assembly 40, a Fenwal phlebotomy needle assembly made by Baxter Healthcare Corporat~on. The assembly t5 used to dra~ blood for collection. The assembly 40 lncludes a rlgld cannula or needle 42, hub 44 and tublng 46. Here, the blunt end 48 of the needle 42 may extend beyond the plastic hub 44. The proxlmal end 50 of the tubing 46 is secured directly to the blunt end portion 48 of the cannula 42 by means of the hub 44 molded tightly about ,the needle 42 and tubing 46. A bondlng agent may be used between the needle 42 and tubing 46. The internal diameter of the tubing 46 ln the flow path adjacent the blunt end port10n 48 remalns greater than the internal diameter of the needle 42.
Automated apheresis lnstruments lnclude means for monitorlng the pressure requlred to generate the des~red hlgh flow rates and 1nclude some safety features to ,l~mlt the flow in ease the fluld pressures go outs~de the establlshed range. For example, the Autopheresls-C instrument monltors the pressure required to drlve a spectfic blood flow rate to and from the donor dur~ng every eycl.e o~
the procedure. One cause of an lncrease 1n pressure stems from the gradual formatlon of a blood clot (pr1marily platelet and flbrln clots) near the blunt end of the stalnless steel cannula, especially ln the needle, hub or tublng at the portlon of the fluld flow path adjacent the blunt end oF the needle. Such a ,clot gradually reduces the cross-sectional area of the lumen that ls open for blood to flow through the cannula and necessarily tncreases the pressure required to malntain a g~ven blood flow.
Referrlng now to Figures 1 and 2 there ~s ~llustrated a need1e assembly 60 made in accordance with the present ~nvent~on. The assembly 60 ~ncludes a hollow cannula or needle 62, typ~cal1y made -, :~. ' .
: .
: , WO 91/19~22 P~/US91/04191 of stalnless steel, a hub 64 typically made of a plastlc mater~al such as polyYlnyl chlor~de (PVC), and tublng 66 such as plastlc tublng, whlch may be made of PVC. The hub 64 may lnclude wlngs 67 extendlng therefrom for attach~ng the assembly to a d~nor.
More part~cularly, the needle 62 1ncludes a shank ~8 havlng a polnted end 70 extend~ng from and contlnuous w1th one end of the shank 68. The shank ~8 lncludes an opposlte end 7Z. The shank has a substantlally constant outer dlameter and a substantlally con;tant lnner dlameter. The assembly of the present 1nventlon ~ay be made in different sizes but ln one preferred embodl~ent the outer diameter of the needle shank 68 is about 0.065 tnch. The lnner diameter of the needle shank 68 is about 0.056 inch. The wall thlckness of the needle ~s about 0.0045 lnch. ~he needle 62 in the preferred embodiment ls a 16 gauge needle, but thls ls not necessary.
The plastic hub 64 ~s mounted about the ctrcumference of a portion of the shank ln close flttlng relation thereto, 1ntermedlate the pointed end 70 and the oppos~te end 72. The opposite end 72 of the needle 68 extends beyond the hub 64. The hub 6~ may be in~ectlon molded about ~he ne~dle 62 or the hub 64 may be adhes~vely bonded to the needle 62. Constructlon can 1nclude an ~nterference fltment between the hub and needle.
The tubing 66 ~ncludes a dlstal end 76 and a needle-proxlmal end 78. The needle-prox~mal end 78 of the tublng ls mounted about the outside of the needle opposite end 72 1n an interference flt, so that the tub1ng 1nternal d~ameter about the needle opposite end 72 is stretched to a d~lmenslon greater than 1ts nor~al ~rternal diameter. In accordance with the presrnt invention, the tub~ng normal lnner d~ameter ls no greater than, and 1s pre~erably less than, the ~nternal diameter of the needle oppos~te end 72. The tublng end 78 may be secured about the needle opposlte end 72 w~th a medlcal grade bonding agent such as an adheslve or solvent, such as cyanoacrylate or an RTV or UV-eured medlcal grade elas~omer, although ln the preferred embodiment the bond~ng agent ls not necessary.

. .

WO 91/19522 PCl/US91/04191 ~ ~ ~ 4 ~J ~ r/

In the preferred embod~ment the tubln~ 66 has a length of approximately 1 l/2 lnches although thls ls not critlcal to the !~
tnventlon. The dlstal end 76 of the tublng ls eonnected to a Y-connector 79. Antlcoagulant tublng 80 and bloDd component tublng 582 each 1nclude known Luer assemblles 84 86 mounted Bt the dlstal ends 88 90 respectively of the tublng 80 82. ~he antlcoagulant -~
tube 80 and blood component tube 82 each 1nclude proximal ends 92 94 mounted to the Y-connector 78 such that the lnterlors of the tubing 66 80 and 82 are in flow communicati~n. In accordance w~th lOknown procedure the antlcoagulant tub~ng 80 ls ~onnected to an anticoagulant supply line 96. The anticoagulant line 96 is connected at its opposite end to a source 98 of anticoagulant such ~ -as a flexlble container of anticoagulant liquld.
The tubing B2 is connected to a blc~d separatlon set lO0 ~n 15accordance ~lth known procedure. In the preferred embodiment the lnternal diameter of the blood component tubing 82 1s about O.lZ5 lnch although this ls not cr~tital to the present 1nventlon. The blood separat1On set may be the set sold by Baxter Healthcare Corporation for use in the Autopheres1s-C~ blood separation 20lnstrument. The set lOQ including the separat1On chamber 102 and blood fraction collection conta1ner 104 are lnstalled on the blood separatlon 1nstrument 106. .
As may be ~een best 1n F19ure 2 the 1nner d1ameter of the tublng 66 returns to its normal lnternal diameter in close proximity 25to the opposite needle end 72 and preferably at an axial distance no greater than about 0.015 lnch from the oppos~te needle end 7Z in order to minimize the defined space 108 adjacent the end surface 110 of the needle oppos~te end 72. In the preferred embodiment where the outer diameter of the needle shank 68 1s ab~u~ 0.065 inch the 30tubing 66 has an outer diameter of 0.125 1nch and an ~nner d~ameter of 0.052 lnch which is approximately 0.004 lnch less ~han the 1ns1de dlem~ter of the needle 62.

: ~' ., : .
'" ', WO gl/~952~ PC~/US91/04191 2 ~

Thus, by provid~ng structure ~hereln the tubing ~6 returns to its normal ID ln close proxi~ty to the end 72 of the needle and provlding a tublng normal ID no greater the I~ of the needle shank 68, there is created a fluild flow path havtng a cross-sectlonal area tn the tublng ad~acent the needle end 72 that ~s no greater than, and preferably less than, the cross-sectional area of the tub~ng ln :
the end 72 of the needle 62.
The needle assembly 60 of the present lnvention is especlally useful for the return of packed tells to the donor through the phlebotomy needle 62. Wlth the Autopheresls-C~ devlce ln a platelet collection protedure, the hematocrlt of the returnlng packed cells may be about 55% and the hematocrit of packed cells returned to the donor ln a plasma collectlon procedure may be about 70%. The needle assembly of the present invent~on ls also espeeially useful when lower levels of anticoagulant are added to the extracorp~real blood such as 6X anticoagulant by volume or lower, where clottlny 1n the needle would be llkely to occur absent the needle design of the present invention, especlally upon return of blood to the donor.
While au~omated blood separatlon pro~edures have typically used antlcoagulant ratios of 8% or h1gher~ it has recently been ~ound to : :be deslrable to use lower levels of antlcoa3ulant. Use of lower levels of anticoagulant increases the need for the needle asse~bly of the present lnvention. - -In this specification the ant koagulant levels 1ndlcate the percent ant1csagulant by volume for antlcoagulant-a~ded whole blood. Stated dlfferently, an BX level means 8 parts antlcoagulant to 92 parts whole blood, or 8 parts anticoagulant ~n lO0 parts antlcoagulated whole blood. Th~s is the standard system for ..
compar1ng ant1coagulant levels in the m~d1cal eo~mUnitY-30 : Furthermore, ~hile anticoa~ulant levels in se~arated blood ~ract~ons : : :: vary, comparisons are typically made by looking at the anticoa~ulant eYel in the whole blood to ~e separated.
. ~ .
, .

WO 91/19522 ;~ ~ '" D5 P~ ~ t`; PC~/US91/~4191 _ 10 --Referrlng no~ to Table 1, there ls shown a clot occlus~on ratlng system for platelet collectlon procedurels performed on the Autopheresls-C devlce. The Table compar@s procedures uslng the prlor art needle assembly 10 lllustrated 1ll Flgure 3 and blood S hav1ng anticoagulant levels of ~X, 5%, and 4Z, and proeedures uslng the needle assembly 60 and blood havlng 4X ant~cQagulant. The antleoagulant used ln all procedures was ACD-A, a known type of antlcoagulant. The ratlng ~as vlsually estlmated, wlth the ald of a stereomicroscope. R~tlngs 2, 3 and 4 approxlmate the percentage of the needle lumen or bore occluded by the ~lot.
.. .
TABLE I
CLOT OCCLUSION RATING:
POST PROCEDURE
Ratinq Descr~ptiQn . ~
O No vlslble clot 1 Clot vislble 2 Clot > 2S% of lumen 3 Clot > 50X of lumen 4 Clot > 75% of lumen . . .
A~D-A RatlQ(~ eraa&_Rat~na 6% (Flg. 3) 1.5 (N.13) 5% (Flg. 3) 1.7 (N~7) 4% ~Fig. 3) 2.8 (N-12) 4X (Needle Assembly shown O (N~10) -30in Figs.l and 2) ~
N~sample slze ;
',~ ,i~. ' ~ ~ ' " '.' ' ','~' . '.
'' ,; ' ,':, ~,'.

. .. . . ~ ,. . , ,; . ,~- , , ;

WO 91/19522 PCl/US91/04191 . .
2 ~

Even at a 6~ antlcoagulant level the prlor art needle assembly lO had a rating of 1.5 for clot slze. As expectsd the rlot slze rat~ng became larger as the ant~coagulant level was decreased. It is lmportant to note that the clot size ra~lng ls a mean value. At the 4% antlcoagulant level w~th the prlor art needle (2.8 rat~ng) there ~ere serlous clotting occluslons ~hlch necessar11y stopped some of the blood separation procedures before they were flnlshed.
Remarkably. wlth the needle assembly 60 of the present ~nvention operated at an ant~coagulant level of 4% the ratlng was zero. Stated d~fferently no occlus~ve or adherent clots wer~
vls1ble with the stereo~icroscope.
The reduced clotting tendency of the new needle assembly of $he present invention becomes espec~ally ~mportant w~th procedures where ~t ~s des~rable to reduce the antlcoagulant lèvel ln the blood or blood components.
Wh~le not lntending to be bound by a part~cular theory of operation lt is bel~eved that the needle assembly of the present lnvent~on works so wetl because from the tublng 66 lnto the needle 68 the internal d1ameter of the flow path ls malntalned constant or 1ncreases ln the direct~on of return flow to the donor. Th1s design essentially alleviates the clot formatlon problem and appears to do so independent of the antlcoagulant level. Ey causing the 7nternal diameter of the tubing ad~acent to the needle end 72 to be equal to or less than the internal diameter of the needle the flow velocity of l~quld ln the tubing ~ust beyond the need!e end 72 ~s about equal to flow velocity in the needle. In prior art deslgns ~t 15 bQlleved that flow velocity slows as llquld exlts the needle ~nto the ad~acent tub1ng.
Further~ore the des19n of the needle assembly of the present invention minimizes or el~minates the flow stagna~lon area ~.e. the defined space 108 adjacent the needle blunt end with~n which there ~s no sign~flcant liquld flow.

.

- .
:
'' :
" ' W O 91/19522 .f ~ 7~ " P~TtU~9ltO4191 While a speclflc embodlment of the present 1nventlon has been set forth ln detall, lt ~lll be understood ~hat modlf~catlons may be made to the needle assembly ~hlle st~ll remalnlng wlthln the splrlt and scope of the appended clalms.
:.

.. .. .

-~

lS ;.

., ~: -,

Claims

What is claimed is:

1. A needle assembly comprising a. a hollow steel needle including a shank having a pointed end extending from and continuous with one end of the shank and an opposite end opposite said pointed end, said shank having an outer diameter and an inner diameter;

b. a plastic hub mounted about the circumference of a portion of the length of said shank in close fitting relation thereto, intermediate said pointed end and said opposite end, said needle opposite end extending beyond said hub; and c. hollow tubing having a proximal end, said tubing including a normal internal diameter and a normal outer diameter, said tubing proximal end mounted about the outside of said needle opposite end in an interference fit;

d. wherein said tubing normal internal diameter is no greater than said needle internal diameter.

2. The needle assembly in accordance with Claim 1, wherein said tubing normal internal diameter Is less than said needle internal diameter.

3. The needle assembly in accordance with Claim 1, wherein said tubing internal diameter about said needle opposite end is stretched to a dimension greater than normal internal diameter.

4. The needle assembly in accordance with Claim 3, wherein said tubing internal diameter reduces from said stretched internal diameter to said normal internal diameter in close proximity to said opposite needle end.

5. The needle assembly in accordance with Claim 4, wherein said normal internal diameter is reached at an axial distance no greater than about 0.015 inch from said opposite needle end.

6. The needle assembly in accordance with Claim 1, wherein said tubing normal internal diameter is at least about 0.002 inch less than said needle internal diameter.

7. The needle assembly in accordance with Claim 1, wherein said normal tubing internal diameter is about 0.004 inch less than said needle internal diameter.

8. The needle assembly in accordance with Claim 1, further comprising a medical grade bonding agent between said needle opposite end outer diameter and said tubing.

9. The needle assembly in accordance with Claim 8, wherein said bonding agent is an adhesive.

10. The needle assembly in accordance with Claim 8, wherein said bonding agent is a solvent.

11. The needle assembly in accordance with Claim 8, wherein said bonding agent is cyanoacrylate.

12. The needle assembly in accordance with Claim 2, further wherein said needle internal diameter is about 0.056 inch, and said tubing normal internal diameter is about 0.052 inch.

13. The needle assembly in accordance with Claim 12, wherein said needle outer diameter is about 0.065 inch.

14. The needle assembly in accordance with Claim 12, wherein said tubing outer diameter is about 0.125 inch.

15. The needle assembly in accordance with Claim 1, further comprising a Y-connector mounted to said tubing at the distal end thereof, anticoagulant supply line tubing and blood separation set tubing, each having a proximal end, said proximal ends mounted to said Y-connector such that the interiors of said needle assembly tubing, said anticoagulant tubing and said blood separation set tubing are in flow communication.

16. A needle assembly for the transfer of blood components in a pump-assisted blood transfer operation wherein plasma-depleted blood is returned through the needle to a donor, the needle assembly comprising:

a. a hollow, steel needle including a shank having a pointed end extending from and continuous with one end of the shank and an opposite end opposite said pointed end, said shank having an outer diameter and an inner diameter;

b. a plastic hub mounted about the circumference of a portion of said shank in close fitting relation thereto, intermediate said pointed end and said opposite end, said needle opposite end extending beyond said hub; and c. hollow tubing having a distal end and a needle-proximal end, said tubing including a normal internal diameter and a normal outer diameter, said tubing proximal end mounted about the outside of said needle opposite end in an interference fit, so that said tubing internal diameter about said needle opposite end is stretched to a dimension greater than the normal internal diameter of said tubing;

d. wherein said tubing normal internal diameter is less than said needle internal diameter; and e. blood set tubing having a proximal end coupled in flow communication with said tubing distal end.

17. The needle assembly in accordance with Claim 16, wherein the plasma-depleted blood returned to the donor through said needle has a hematocrit of at least about 55.

18. The needle assembly in accordance with Claim 16, wherein the plasma-depleted blood returned to the donor through said needle has a hematocrit of at least about 70.

19. The needle assembly in accordance with Claim 16, wherein the plasma-depleted blood returned to the donor through the needle is obtained from whole blood having an anticoagulant level less than about 8% by volume.

20. The needle assembly in accordance with Claim 16, wherein the plasma-depleted blood returned to the donor through the needle is obtained from whole blood having an anticoagulant level of not more than about 6% by volume.

21. The needle assembly in accordance with Claim 16, wherein the plasma-depleted blood returned to the donor through the needle is obtained from whole blood having an anticoagulant level of not more than about 4% by volume.

22. The needle assembly in accordance with Claim 8, wherein said bonding agent is a medical grade elastomer.