Multiple sample needle assembly with vein indication

A multiple liquid sample needle assembly is provided which utilizes a housing with a porous filter which is gas permeable and liquid impermeable for providing gas displacement venting for gas displaced by a liquid sample received in the housing. The invention incorporates a translucent or transparent housing for determining whether access to the liquid sample in question has been obtained. The filter of the assembly cooperates with the sequential application of a plurality of vacuum collection tubes to close off passage of air therethrough during the taking of the samples. In addition, the assembly is arranged to accommodate separate I.V. and negative pressure cannulas, or a single cannula with an I.V. and negative pressure point at opposite ends thereof.

BACKGROUND AND STATEMENT OF THE INVENTION 
This invention relates to an assembly for collecting a liquid sample from a 
patient, such as a blood sample. More particularly, this invention relates 
to a needle assembly for collecting sequentially multiple liquid samples 
from such a patient. The device of the invention utilizes a receiving 
chamber with walls which are translucent or transparent for visually 
indicating whether or not proper access to the source of the sample in 
question has been achieved. Moreover, the housing or chamber which 
receives the sample incorporates therein a porous filter which filter is 
comprised of a material which provides, simultaneously, a liquid barrier 
for the sample received in the housing, and a gas displacement discharge 
passage for gas displaced by the liquid sample received in the chamber. 
The filter in the housing is positioned in such a way that it extends from 
the chamber to an exit point for the discharge of gas out of the housing 
chamber, which exit point may be covered by the cooperative engagement of 
the flange of the rubber sleeve or valve means which extends over the 
discharge opening of the negative pressure cannula during periods when a 
sample is not being discharged therefrom into an evacuated tube. 
Subsequently, when a liquid sample is to be discharged into an evacuated 
tube placed over the negative pressure cannula, the stopper for the tube 
engages the sleeve in a conventional manner. The negative pressure point 
of the negative pressure cannula passes through the stopper of the 
evacuated tube and the stopper moves along the negative pressure cannula 
toward the housing. In doing so, the point of the negative pressure 
cannula pierces the sleeve, and causes the sleeve to collapse and move 
toward the adjacent housing face. Thus, the flange of the sleeve is caused 
to engage the housing face, closing off the exit end of the filter device. 
For this reason, when a sample is being collected from the housing chamber 
into an evacuated tube, no air is allowed to pass through the filter from 
outside into the chamber. 
Once the evacuated tube is withdrawn from the negative pressure cannula, 
the sleeve moves outwardly to reseal the discharge opening of the negative 
pressure cannula and the sample chamber in the assembly housing until the 
next evacuated tube is inserted into the assembly. Thus, with the 
sequential application of a series of evacuated tubes, the tubes move the 
sleeve out of engagement with the negative pressure discharge opening or 
point of the negative pressure cannula, and cause the flange of the sleeve 
to engage the exit opening of the filter to prevent any air passing into 
the sample chamber. 
As discussed above, it is desirable to provide a mechanism whereby the user 
of such a needle assembly can be informed when the intravenous needle has 
penetrated the vein of the patient for collecting a blood sample. Many 
times, in collecting blood from a patient, it is difficult to locate the 
vein, or for other reasons blood flow into the collecting device is not 
adequate. In those instances, it is advantageous to be able to make a 
quick determination that entry into the vein has been made and that blood 
is flowing into the needle assembly. 
Once this determination has been made and the vein entry achieved, the 
evacuated blood collection containers can be inserted, sequentially, as 
discussed above, into the collection assembly in accordance with well 
known techniques of collecting blood samples during a single collection 
procedure. Thus, by utilizing a translucent or transparent chamber, with 
the assembly of the invention herein, the fact that blood flow has been 
obtained is quickly realized simply by the user visually noting blood 
collecting in the housing chamber of the assembly of the invention here. 
Furthermore, as discussed above, with the utilization of the porous filter 
in the housing wall, the filter allows for displacement of the air from 
the housing chamber so as to allow room for receiving the blood sample 
being collected. 
A prior art device which recognizes the utilization of a porous material 
for providing a venting for displaced air during receiving a blood sample 
is taught in U.S. Pat. No. 4,207,870, issued June 17, 1980. That assembly 
requires a separate one-way valve construction which opens and allows 
blood to travel from the vein of the patient and through the housing and 
into an evacuated container. Other related applications include co-pending 
U.S. applications Ser. No. 160,781 filed June 18, 1980, now U.S. Pat. No. 
4,340,068, issued July 20, 1982, Ser. No. 284,894 filed July 20, 1981 and 
Ser. No. 311,494 filed Oct. 15, 1981. 
Other objects and advantages of this invention will be apparent from the 
following description, the accompanying drawings and the appended claims.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to the drawings, in which like reference characters refer to like 
parts throughout the several views thereof, FIG. 1 shows the basic 
components of needle assembly 10 including a hub assembly 12 with an 
annular housing 22 which is translucent or transparent for indicating the 
presence of blood in chamber 48 defined by annular housing 22. The hub 
assembly includes a front wall 24 with a bore 34 therethrough for 
receiving an intravenous cannula 26 having a point 46, which cannula 26 is 
fixed in bore 34 by appropriate adhesive 32. The assembly includes a rear 
housing portion 14 having a front flange 16 for cooperating with a rear 
flange 23 of hub assembly 12. The flanges 16, 23 are bonded at 25 with a 
conventional adhesive. Rear housing portion 14 includes an annular rear 
extension 18 with helical turns 20 on the outer surface thereof for 
receiving an evacuated tube holder thereon, as will be discussed below. 
Rear extension 18 includes, further, a bore 19 for receiving a negative 
pressure cannula 28 therein. 
As can be seen in FIG. 1, negative pressure cannula 28 includes a point 44 
at the discharge end thereof. Negative pressure cannula 28 is fixed in 
bore 19 by an appropriate adhesive 36. Extending from the rear face 31 of 
rear extension 18 is a rear flange 38 for receiving thereover the rubber 
sleeve 40. The flange 38 cooperates with flange 42 of sleeve 40 to hold 
sleeve 40 in place over negative pressure cannula 28, as shown in FIG. 1. 
The front face 33 of sleeve flange 42, as can be seen in FIG. 1 is spaced 
from rear face 31 of extension 38 to define an air passage 29. As can be 
seen in FIG. 1, further, a sintered filter 30 extends through rear 
extension 18 from chamber 48 to rear face 31. Filter 30 is comprised of a 
material which is gas permeable, and liquid impermeable. As purely 
illustrative of materials which may be used to form filter 30, sintered 
polyethylene may be selected or an open cell polyethylene foam or other 
similar moldable polymeric materials such as porous polypropylene, or 
porous polyfluorocarbons. 
Referring now to FIG. 2, assembly 10 is shown with an evacuated tube holder 
54 received on the helical turns 20 of rear extension 18. Received in 
holder 54 in conventional manner is an evacuated tube 50, the stopper 52 
of which has been penetrated by the point 44 of negative pressure cannula 
28, in the usual manner. As can be seen, further, in FIG. 2, front face 39 
of stopper 52 has engaged and caused the collapse of rubber sleeve 40. 
This engagement has urged flange 42 of sleeve 40 against the rear face 31 
of rear extension 18 closing passage 29, and front face 33 of flange 42 
covers the exit end of filter 30. As will be appreciated, at this point in 
the use of the device of the invention, intravenous point 46 of I.V. 
cannula 26 will have penetrated the vein of a patient so that blood has 
passed through I.V. cannula 26 into chamber 48. Any air in the chamber 
will have passed through filter 30, and passage 29. The user will observe 
that such penetration has taken place because blood will be indicated in 
the translucent or transparent chamber 48 defined by the annular housing 
22. Thus, upon penetration of point 44 through stopper 52 of the evacuated 
tube 50, the negative pressure will cause the blood collected in chamber 
48 to pass through negative pressure cannula 28 into evacuated chamber 50. 
Because the filter 30 is closed at the outer end thereof, no air may 
return to chamber 48. 
As will be appreciated, once a sample has been obtained from chamber 48, 
and is contained in evacuated tube 50, it may be removed from negative 
pressure cannula 28. This removal causes the rubber sleeve 40 to move back 
to the position shown in FIG. 1 for resealing of negative pressure cannula 
28, until the sequential insertion of the next evacuated tube 50. It will 
be appreciated, further, that I.V. cannula point 46 will remain in the 
vein of a patient during this exchange of evacuated tubes 50. 
Referring now to FIG. 3, a further embodiment of the invention is shown in 
which a single cannula 60 is utilized having a negative pressure point 64 
and intravenous point 62. In order to provide communication between the 
cannula 60 and chamber 48 defined by the transparent annular housing 22, a 
slot 66 is formed in cannula 60. Cannula 60 is fixed in bore 34 of the 
front wall 24 of the intravenous hub assembly 12 by an appropriate 
adhesive 68 as will be appreciated. The remaining parts of the assembly of 
FIG. 3 are the same as those shown and described in FIG. 1. 
Thus, as will be appreciated from the above discussion, a blood collection 
needle assembly is provided in accordance with this invention for 
collecting multiple samples, as required, in combination with an 
arrangement for indicating vein entry to the user of the assembly. 
Moreover, the arrangement of the invention here is in the form of a 
simplified porous filter operating to provide, simultaneously, passage of 
a gas and blockage of a liquid. A conventional sleeve for blocking the 
discharge end of the negative pressure cannula is utilized in combination 
to provide a closing off or valving of the filter preventing air passage 
during periods of taking of samples, with the sleeve being moved into 
engagement for blocking or valving the filter by the sequential insertion 
of the negative pressure cannula into a plurality of evacuated tubes for 
receiving the separate multiple blood samples. The arrangement of 
apparatus herein, as will be appreciated, is an extremely simplified and 
an inexpensive arrangement of apparatus for manufacturing. It is 
particularly appropriate for mass production techniques, since the device 
of the invention will be used only once and then thrown away, after 
multiple samples have been taken with a single vein entry. 
While the methods and forms of apparatus herein described constitute 
preferred embodiments of this invention, it is to be understood that the 
invention is not limited to those precise methods and forms of apparatus 
and that changes may be made therein without departing from the scope of 
the invention which is defined in the appended claims.