Intravenous Needle Assembly

Abstract

A plug having a slitted diaphragm for venting air from, but preventing the passage of blood from, a transparent blood-detecting chamber located on the proximal end of the hub of a hollow pointed hypodermic needle during a venipuncture procedure.

Description

BACKGROUND OF THE INVENTION

This invention relates to intravenous needle assemblies and, more particularly, to a hub construction and plug usable with an intravenous needle for detecting the presence of the needle point within a blood vessel and for preventing the flow of blood from the assembly during the venipuncture procedure. The device also provides means for venting air to enable the blood to flow from the blood vessel into a blood-detecting chamber located in the needle hub.

During the placement of a needle or flexible plastic catheter into a vein or other body member, it is desirable to determine whether or not the tip of the needle or catheter is properly situated within the vessel. Because the introduction of the assembly into the vein is normally accomplished by the use of a rigid metallic needle, it is impossible to detect the presence of blood in the needle and needle hub and, likewise, the presence of the needle tip in the vein. Introducer needles are normally equipped with a hub and some prior art devices have equipped the hub portion of the needle with transparent flash chambers into which the blood may flow to indicate that the needle point is properly placed. However, in the past, the flow of blood from the flash chamber was controlled by a plug that was inserted into the chamber after the blood had actually appeared therein. Consequently, it often occurred that blood would flow from the chamber prior to the insertion of the plug completely within the chamber to prevent the flow of blood therefrom.

Therefore, it has been desirable for many years to provide a blood-detecting chamber into which blood could flow to indicate that the needle point had been properly placed, which chamber is provided with a means for venting air therefrom to permit the flow of blood thereinto and to prevent the flow of blood from the chamber.

SUMMARY OF THE INVENTION

The present invention provides a single plug which may be firmly positioned within the proximal end of a transparent blood-detecting chamber on an introducer needle hub. This plug is designed to vent air from the blood-detecting chamber when the introducer needle is positioned within a blood vessel so that blood may flow from the vessel into the chamber. The plug is also designed to prevent the flow of such blood from the blood chamber until such time as the plug is removed therefrom. The plug has a relatively simple design, with no moving parts, and it may be quickly inserted and removed from the blood detecting chamber.

In the preferred embodiment of the invention, the plug is provided with an axial opening across which a thin plastic diaphragm is positioned. The diaphragm has an opening therethrough which is of sufficient size to permit air to pass from the blood chamber but to prevent the flow of blood therethrough.

BRIEF DESCRIPTION OF THE DRAWING

The invention will be particularly described with reference to the following detailed description of the preferred embodiment of the invention when considered together with the attached drawing, in which:

FIG. 1 is a perspective view of an intravenous needle assembly showing the plug of the present invention in a position removed from the end of the blood-detecting chamber;

FIG. 2 is a longitudinal cross sectional view of the needle assembly of FIG. 1 showing the plug of the present invention inserted within the blood-detecting chamber; and

FIG. 3 is an end view of the plug as viewed from the left in FIG. 2.

Referring to FIGS. 1 and 2, the preferred embodiment of the intravenous needle assembly of the present invention is shown generally at 10. The assembly comprises an introducer needle 11 which is in the form of a hollow hypodermic needle having a point 12 on one end thereof. Needle 11 is secured at its blunt end to a plastic hub 13 which has a transparent blood-detecting chamber 14 integral with its proximal end. The entire hub and blood-detecting chamber assembly may preferably be molded in one piece from a suitable clear plastic material. In the preferred embodiment, needle 11 serves the function of introducing a flexible plastic catheter 15 into a vein or other body vessel. Catheter 15 is attached to a hub 16 at its proximal end and hub 16 is adapted to be removably secured to a fitting 17 on the distal end of hub 13.

Except for the transparent blood-detecting chamber 14, the intravenous needle assembly thus far described is very similar to the assembly described in U.S. Pat. No. 3,094,122. The procedure used for the introduction of such an assembly into a vein is thoroughly illustrated in this patent and it may be seen that it is necessary to perform a relatively complicated procedure including the utilization of a syringe during the introduction of the needle into a vein in order to ascertain the location of the needle point within the vein and in order to vent the system so that blood may flow from the vein through the catheter assembly.

The present invention eliminates the necessity for such a complex operation and provides a relatively simple one-piece plug which performs at least one of the functions of the syringe in the above-cited patent. This plug is shown generally at 20 in the drawing and includes an enlarged gripping surface 21, a tapered neck portion 22 for insertion into the proximal end of blood-detecting chamber 14 and a diaphragm 23 having a diametrically oriented slit 24 formed therein. Plug 20 may be molded in one piece with diaphragm 23 formed at the distal end of the plug from a relatively thin portion of the plastic material. Slit 24 may then be formed in the diaphragm by a cutting or other suitable procedure.

The size of slit 24 is not critical, however, it has been found to be desirable to form the slit in diaphragm 23 without the removal of any of the plastic material. This assures that air may be vented from the blood-detecting chamber but provides a seal against the passage of blood from the chamber. For purposes of illustration, slit 24 has been shown in the Figures in an enlarged condition so that it will be apparent that there is an opening in diaphragm 23.

As stated above, the procedure for introducing a needle and catheter into a vein is very adequately shown in U.S. Pat. No. 3,094,122. The needle assembly of the present invention may be introduced in a similar manner and this procedure will be described below.

To initiate the introduction of the needle into a vein, the unit is fully assembled as shown in FIG. 2 with catheter 15 positioned over needle 11 and with plug 20 firmly seated within the proximal end of blood-detecting chamber 14. The introduction of the needle point 12 into a vein will cause blood to flow through the hollow needle and into blood-detecting chamber 14. Air contained within the hollow needle and the blood-detecting chamber will be forced by the blood through slit 24 in plug 20 out into the atmosphere. Blood flowing into chamber 14 can then be detected by the operator through the transparent wall of the chamber. Because of the extremely small size of slit 24, blood will be retained within the chamber and not permitted to pass through the axial opening in plug 20. When it is desired to attach an administration set or other device to the catheter hub, it is only necessary to withdraw the needle from the catheter and, thereby, expose the open female luer end of hub 16 for the appropriate male fitting.

On the other hand, needle 11 may be used independent of catheter 15 and an administration set or other device may be attached directly to the blood-detecting chamber 14 by merely removing plug 20 therefrom.

It will be apparent from the foregoing description, that the subject invention provides an effective, yet relatively simple, device for detecting the presence of an introducer needle point within a vein and for preventing the loss of blood from the needle assembly. This is accomplished automatically without the necessity of manipulative procedures required by prior art devices.

Claims

What is claimed is:

1. An intravenous needle assembly comprising: a hollow pointed needle; a hub secured to the proximal end of said needle, said hub having a transparent blood-detecting chamber; and a plug removably secured in said chamber, said plug having an axial opening therethrough and a thin diaphragm disposed across said opening, said diaphragm having a slit formed therein for permitting the passage of air from said chamber, the amount of material in said diaphragm being substantially unchanged by the formation of said slit therein.

2. The intravenous needle assembly of claim 1 wherein said diaphragm is located adjacent the distal end of said plug.

3. The intravenous needle assembly of claim 2 wherein said slit is diametrically oriented.

4. The intravenous needle assembly of claim 1 further comprising a flexible plastic intravenous catheter disposed over said needle.

5. The intravenous needle assembly of claim 4 wherein said catheter is secured to a hub which is removably attached to the distal end of said needle hub.