Blood collecting needle with vein indicator

A needle assembly for evacuated blood collection tubes or containers comprises a single needle cannula, a needle cannula support made of a translucent or transparent material provided on the middle portion of the needle cannula, a blood flow confirmation passage formed in the interior of the needle cannula support and communicating with one end of the needle cannula, said one end being covered with an elastomeric resilient cap, and an air-permeable, blood repellant plug provided at an opening end of the passage.

BACKGROUND OF THE INVENTION 
The present invention relates to a needle assembly for evacuated blood 
collection tubes or containers, one end of which needle is inserted into 
the vein of a blood examinee, and the other end of which is adapted to be 
communicated with the interior of a evacuated blood collecting container 
so as to be able to collect blood in an amount responsive to the negative 
pressure in said container. 
A known needle assembly of this kind is illustrated in FIG. 1. In this 
device, a needle cannula support A is secured to the middle portion of a 
stainless needle cannula B, and one end of the needle cannula support A is 
provided with a rubber cap C for covering one end of the needle cannula B. 
With such kind of needle assembly, the other end, i.e. the tip of the 
needle cannula B, is inserted into the vein of a blood examinee and a 
blood collection container is fitted over rubber cap C and communicating 
onto the other end of the needle cannula so as to communicate with the 
interior of the blood collection container. Blood entering the collection 
container provides a first indication that the needle has accurately 
entered the vein of the blood examinee. If it is necessary to reinsert the 
needle in order to draw blood, the negative pressure pre-set in the blood 
collection container may be released resulting in an inability to collect 
a desired amount of blood or the need to employ a further blood collection 
tube. 
To remove such demerits, a variety of needle assemblies have been proposed 
that are constructed in such a way that when inserted into the vein of the 
blood examinee a flow-out of blood can be confirmed. One known example is 
such that a needle cannula is divided into two sections, one of which is 
to be inserted into the vein and the other to be inserted into a evacuated 
blood collection container. A member connecting these two needle sections 
is provided with a transparent blood flow passage, and it is confirmed 
through this passage whether the blood is flowing or not. In another known 
example, the middle portion of a needle cannula is bored with a hole which 
is circumferentially formed with a blood flow confirmation chamber. 
In the known needle assembly where the needle cannula is constituted by two 
needle sections, the member connecting the two needle sections requires a 
lot of components whereby manufacturing steps and cost increase. Moreover, 
unless the air not only inside the needle but also in the transparent 
blood flow passage within the member connecting the two needle sections 
flows out, the blood does not flow, so that the structure needed to solve 
these problems becomes complicated. 
On the other hand, according to a needle assembly where the needle cannula 
is bored with a hole which is circumferentially formed with a blood flow 
confirmation chamber, the confirmation chamber must be retained under 
negative pressure or released to the outside, and therefore as in the 
above case, the structure becomes complicated and the manufacturing cost 
increases. 
Furthermore, such kinds of blood collection needle assemblies are used for 
collecting multiple samples of blood from a blood examinee, ordinarily 
changing the blood collection container, and each time a sample of blood 
is collected, the rubber cap at one end of the needle cannula is 
punctured. Generally, the tip of a needle is obliquely cut and the tip 
point is sharpened (lancet-shaped). However, since the tip point is 
positioned at the outer periphery of a needle cannula, it is feared that 
in manufacturing needle assemblies for blood sampling the rubber cap might 
be impaired when it is mounted over the needle tip. Conventionally, 
therefore, the sharpened tip point is bent toward the center axis of the 
needle cannula or obliquely cut while retaining a round point shape. 
Needles having such bent tips substantially decrease the danger of 
impairing the rubber cap when the cap is mounted in manufacturing the 
needle assemblies. On the other hand, however, the rubber cap is apt to be 
hooked by a bent tip point when the cap is returned to its original 
position when a blood collection container is disengaged from the needle. 
Moreover, the bending step increases manufacturing cost. With a rounded 
point, the cutting opening of the rubber cap becomes wider when punctured 
with a needle. Accordingly, when repeatedly punctured by other evacuated 
blood collection tubes, the rubber cap tends to lose its sealing property 
whereby such a rubber cap is not suited for repeated sampling of blood. 
Furthermore, these needle assemblies are disposable so that it is desired 
to provide them at as low a cost as possible. It is further required to 
guarantee safe and certain functioning so that the user such as doctor or 
nurse may not directly contact blood when blood is collected. 
SUMMARY OF THE INVENTION 
The object of the present invention is therefore to provide a needle 
assembly for evacuated blood collection tubes or containers, which is easy 
and safe to use while solving the forementioned problems, which is of 
simple structure, and which can be manufactured at low cost. 
In order to achieve the above objects, a needle assembly for use with 
evacuated blood collection tubes or containers according to the present 
invention includes a needle cannula one end of which, in use, is adapted 
for insertion into the vein of a blood examinee and the other end into a 
evacuated blood collection container, a needle cannula support mounted at 
the middle portion of said needle cannula, and an elastomeric resilient 
cap mounted at the other end of said needle cannula. In use, the blood 
collection container is mounted liquid-tight to the needle cannula support 
from the other end side of the needle cannula, which side is fixed with 
the cap, and when piercing the elastomeric resilient cap, the other end of 
the needle cannula is communicated with the interior of the blood 
collection container. The present needle assembly is characterized in that 
the needle cannula support is made of a translucent or transparent 
material and is fixed liquid-tight to the needle cannula at the one end 
side of the cannula, the needle cannula support is provided with a 
longitudinal passage opening to the other end side of the needle cannula 
along the outer periphery of the cannula, and with a radial passage 
extending radially from the inward end of said longitudinal path and 
communicating with the outside, and at least one air-permeable, liquid 
repellant or impermeable plug is anchored in the radial path. 
Preferably, the longitudinal path in the needle cannula support may be 
circularly formed around the needle cannula. 
Alternatively, the longitudinal path in the needle cannula support may be 
oval-shaped in section, and it may be constructed to be brought into 
partial contact with the outer periphery of the needle cannula or it may 
consist of a plurality of paths extending along the longitudinal direction 
of the outer periphery of the needle cannula. 
Further, preferably, one end of the radial path in the needle cannula 
support may communicate with the inward end of said longitudinal path and 
the other end may open to the outside to allow this open end to be 
provided with the air-permeable, liquid liquid repellant or impermeable 
plug. 
The air-permeable, blood repellant plug preferably comprises a paper mass. 
Instead, it may be constituted by a synthetic resinous mass. 
Furthermore, the inner edge of the open outer end of said radial path may 
be outwardly tapered. 
Furthermore, preferably, the end of the needle cannula which is covered 
with the elastomeric resilient cap, may extend in parallel with the axis 
of the needle cannula and may be provided with a pointed tip positioned 
within the outer circumference of the needle cannula. 
In the needle assembly according to the invention, the needle cannula 
support made of a translucent or transparent material may be provided at 
the middle portion of a single needle cannula, and the blood flow 
confirmation passage is formed within the needle cannula support. The 
confirmation passage communicates with the tip point at the end side of 
the needle cannula which is covered with the elastomeric resilient cap. 
The open end of said passage is provided with an air-permeable, liquid 
repellant plug, and therefore it is possible to easily confirm whether the 
needle has accurately entered the vein of a blood examinee when blood is 
collected. When the needle cannula is then inserted into a evacuated blood 
collection container (substantially tube) the needle cannula itself is 
blocked from communication with the blood flow confirmation passage within 
the needle cannula support whereby it is possible to collect a desired 
amount of blood through the needle cannula. 
Alternatively, by employing a paper mass as the air-permeable, liquid 
repellant plug it becomes possible to construct a needle assembly without 
substantially increasing manufacturing cost. Moreover, since the liquid 
repellant plug is made of a paper mass, the needle assembly can be easily 
dealt with after use, and in addition to its operational safety it will 
also be advantageous from the viewpoint of preventing environmental 
contamination when the needle assembly is disposed of. 
Furthermore, because of the shape of the tip of the needle which is covered 
by the elastomeric resilient cap, extends in parallel with the axis of the 
needle cannula and has a point which is within the outer circumference of 
the needle cannula, the elastomeric resilient cap does not tend to be 
hooked when mounted in the assembling process of the needles. 
Additionally, even if evacuated blood collection containers are repeatedly 
engaged and disengaged, the cutting opening neither broadens nor is hooked 
whereby the sealability of the cap can be sufficiently retained and 
operability improved.

DETAILED DESCRIPTION 
Referring to the drawings, FIGS. 2-5 illustrate one embodiment of the 
present invention. The reference numeral 1 designates a stainless needle 
cannula, one end 1a of which is formed, in use, to be inserted into the 
vein of a blood examinee, and the other end 1b to be inserted into a 
evacuated blood collection container (substantially tube) not shown. A 
single needle cannula support 2 made of a transparent material is secured 
liquid-tight, with an adhesive 3, as shown, to the middle portion of the 
needle cannula 1 at the side of said one end 1a. Further, as shown in FIG. 
3, the needle cannula support 2 is internally formed with a longitudinal 
passage 4 opening at the other end 1b side of the needle cannula 1 along 
the outer circumference of said cannula and forming a path for the flow of 
confirmation blood, and with a radial passage 5 having a circular shape in 
section, said radial path extending radially and outwardly from the inward 
end of said longitudinal passage 4 and communicating with the outside. As 
illustrated in FIG. 5, the longitudinal passage 4 is annularly formed in 
the circumference of the needle cannula 1. The inner edge of the opening 
end of said radial passage 5 is tapered outwardly. The inside of the 
radial path is anchored with a mass 6 made of paper or synthetic resin, 
said mass serving as an air-permeable, liquid repellant plug which 
prevents blood from leaking to the outside. Paper mass 6 may be a paper 
having a suitable thickness coated with a starch component such as corn 
starch to an extent ranging from several percent to 30 percent, the paper 
being rolled cylindrically, and then dried. 
The opening end of the longitudinal passage 4 of said needle cannula 
support 2 is formed with a flange 7 which anchors an elastomeric resilient 
cap 8 that sealingly covers the other end 1b side of the needle cannula 1. 
Cap 8 is composed of an elastomeric resilient material such as rubber, and 
the receiving portion of the blood collection container, in use, is 
engaged with a threaded portion 9. 
As illustrated in FIGS. 6-8, the tip of the other end 1b of the needle 
cannula 1 is pointed by an oblique cut across its end as shown in FIG. 8 
and by cuts at both sides of the oblique cut such that the pointed tip 
extends in parallel with the axis of the needle cannula, and such that the 
point is positioned more inwardly than the outer circumference of the 
needle cannula 1. Therefore, when the elastomeric resilient cap is mounted 
in the manufacturing procedure there is no longer a fear that the cap 8 
might be hooked by the needle tip. On the other hand, the cap 8 is less 
damaged when a evacuated blood collection container is mounted or 
dismantled, and sealability can be sufficiently ensured even if the blood 
collection container are repeatedly replaced. 
FIG. 9 shows a modified embodiment of the present invention, wherein a 
paper or synthetic resinous, film-like plug 10 is adhered at the outside 
of the opening of the radial path 5. 
FIG. 10 shows another embodiment of the invention, wherein the radial 
passage 5 arranged in the needle cannula 2 has a shoulder 5a near its 
opening, the portion of passage 5 outside shoulder 5a being made larger in 
diameter, and being fitted with a paper or synthetic resinous mass 11 
serving as an air-permeable, blood repellant plug. 
FIG. 11 illustrates a modification of the embodiment shown in FIG. 10, in 
which the air-permeable, blood repellant plug comprises a paper or 
synthetic resinous, film-like plug 12 abutted against the shoulder 5a at 
the end of a cylindrical holding member 13 to which plug 12 is adhered. In 
such case, the film-like plug 12 may alternatively be adhered directly to 
the shoulder 5a in the radial passage 5. 
FIG. 12 illustrates still another modified embodiment of the invention, 
wherein one of the needle cannula support 2 protrudes as shown with the 
reference numeral 2a, and at that protruded end the needle cannula support 
2 is secured by high-frequency melting to the needle cannula 1. 
FIGS. 13 and 14 illustrate modified examples of the longitudinal passage 4 
formed in the needle cannula support 2. In FIG. 13 the longitudinal 
passage 4 is of oval shape in section, and it makes longitudinally a line 
contact at the shorter axis side with the outer periphery of the needle 
cannula 1 thereby forming at the longer axis side two passages 4a, 4b, 
each having a crescent shape in section. On the other hand, in FIG. 14, 
the needle cannula support 2 makes in the longitudinal direction an 
arc-like, surface contact with the outer periphery of the needle cannula 1 
thereby partitioning the blood confirmation passage by two grooves 4c, 4d 
formed longitudinally in the needle cannula support 2. 
FIG. 15 illustrates still another modified embodiment of the invention in 
which a hole 14 is made at the middle portion of a needle 15, said middle 
portion is covered with a single translucent or transparent resinous cover 
or support 16, and a middle hollow portion 17 is provided in said support 
16. A clearance is provided between the needle portion covered with a 
rubber cap 18 and the middle hollow portion 17. The needle 15 is sealingly 
fixed within the translucent or transparent resinous cover 16. On the 
other hand, the middle hollow portion 17 is provided with an opening 19 
and opening 19 is provided with a water-repellant synthetic resinous body 
20 which is used in the form of either a solid body or a membrane 
depending on use conditions. 
FIG. 16 illustrates a modification of the embodiment shown in FIG. 15, in 
which the needle 15 is separated into two needle portions 15a and 15b. 
The resinous body 20 has properties that air permeates therethrough but 
blood or liquid does not. It is important that blood smoothly flows into 
the middle hollow portion 17 from the hole 14 and that the needle 15 at 
the rubber cap 18 side, when the end tip of the needle 15 has entered the 
vein of an upper arm of a blood examinee having normal blood pressure, the 
blood never flows to the outside of the resinous body 20, and that even if 
suction were carried out from the rubber cap 18 side in the evacuated 
blood collection tube or container, the outside air is never sucked in. 
If, in use, the end tip of the needle 15 correctly enters the vein, blood 
flows out of the hole 14 thereby coloring in red the interior of the 
middle hollow portion 17, thus confirming that said end tip is inserted in 
the vein. This enables even an unskilled user to be able to collect blood 
easily with the needle assembly of the present invention. 
When the end tip of the needle 15 correctly enters the vein of a blood 
examinee, blood flows into the middle hollow portion 17 of the resinous 
support 16, so that the correct insertion of the needle can be confirmed 
with unaided eyes. Then the rubber plug of the evacuated blood collection 
tube is pressed toward the needle side covered with the rubber cap, 
causing the blood to flow easily into the tube, whereby it is possible to 
collect blood with a single operation for a plurality of evacuated blood 
collection tubes. 
A suitable air-permeable, blood repellant plug comprises paper coated with 
a starch component such as corn starch, rolled cylindrically into a 
cylinder (being 2.4 mm in diameter and 3.0 mm long), and dried. The air 
permeability of the paper cylinder was measured as described below. 
Blood was put into a container (tube) sealed with a rubber plug, and the 
needle assembly was inserted into the rubber plug while retaining the 
pressure within the container at certain levels by altering the pressure 
range from 40.0 g/m.sup.2 to 7.0 g/m.sup.2 and observations were carried 
out for each of the pressure levels. The pressure gauge used was "HANDY 
MANOMETER" PG-100-101G (made by Copal Denski KK). 
______________________________________ 
Pressure in container 
Flow-in state of blood into 
(g/m.sup.2) needle cannula support 2 
______________________________________ 
40.0 Very good 
30.0 Very good 
20.0 Very good 
15.0 Good 
10.0 It took about one second 
7.0 Hardly flowed-in 
______________________________________ 
Human blood is usually drawn from a vein, and venous pressure is different 
from arterial blood pressure, the latter being generally called blood 
pressure. Venous pressure varies principally in relation to the vertical 
height between the measuring region and the position of the examinee's 
heart. The following are the data as a result of having measured the 
venous pressure of 20 persons in their blood evacuating posture. 
Pressure at the time of normal evacuation in a sitting posture: 65.0-73.0 
g/m.sup.2 
Pressure at the time of normal evacuation in the supine posture: 50.0-60.0 
g/m.sup.2 
In the above testing, 150.0 g/m.sup.2 was the upper limit measured in the 
resisting pressure under which the air could be discharged and the blood 
could be stopped from flowing in case the liquid repellant plug absorbed 
the blood to expand. 
It will be understood from this testing result that the needle assembly of 
the present invention is quite enough to be used if the venous pressure is 
15.0 g/m.sup.2 or higher, that it safely functions up to a pressure which 
is twice that of normal venous pressure, and that it therefore can be used 
in the range of normal venous pressure without any trouble. 
In the embodiments illustrated in the drawings there is used, as the 
air-permeable liquid repellant plug, a paper coated with a starch 
component such as corn starch and the paper is dried in the form of film 
or mass, or a synthetic resinous material impregnated with starch 
component. However, a plug made of paper itself will be more advantageous 
from the viewpoint of manufacturing cost. 
Alternatively, the air-permeable, liquid repellant plug can be provided as 
a double stacking. 
Referring to the radial passage, it is possible that it radially pierces 
the needle cannula support, and that an air-permeable, liquid repellant 
plug may be provided at both of its ends. 
As described above in detail, according to the present invention, a needle 
cannula support made of a translucent or transparent material is provided 
at the middle portion of a single needle cannula, a blood flow 
confirmation passage is formed within the needle cannula support, said 
passage communicating with one end of the needle cannula while said end is 
covered with an elastomeric resilient cap, and one opening end of said 
passage is provided with an air-permeable, blood repellant plug. When 
blood is drawn, it is capable of easily confirming by inserting the needle 
into the blood examinee's vein whether the needle is in correct insertion 
or not. Moreover, at the time of collecting blood into an evacuated blood 
collection container, the needle cannula itself communicates with only the 
blood collection container whereas it is shielded from the blood flow 
confirmation passage within the needle cannula whereby a desired amount of 
blood can be collected through the needle cannula. Accordingly, not only 
does practical blood collection operation become easier, but also the 
frequency of re-insertion of the needle can be reduced so as to lessen the 
examinee's discomfort. 
Further, since the needle assembly for blood collection according to the 
invention employs a needle cannula support comprising a single moulding 
body, and since the air-permeable, liquid repellant plug can be made of 
paper, it is possible to provide the same without substantially increasing 
the manufacturing cost compared with conventional needle assemblies. 
Furthermore, according to the vacuum needle assembly for blood collection 
of the invention, the end of the needle cannula, which is covered with the 
elastomeric resilient cap, extends in parallel with the axis of the needle 
cannula and is pointed in shape while the point is positioned within the 
outer periphery of the needle cannula, and therefore the cutting opening 
of said cap is neither broadened nor hooked so that the sealability of the 
elastomeric resilient cap can be sufficiently retained and the operability 
of the needle assembly can be improved. 
Furthermore, even in the manufacturing procedure, only one constitutional 
component increases and the structure itself of the needle cannula support 
is not complicated, so that the needle assembly for evacuated blood 
collection tubes is structurally simplified compared with those 
conventionally proposed wherein the flow of blood can be confirmed, 
thereby reducing manufacturing cost.