BACKGROUND OF THE INVENTION
A large number of different designs of sheaths and the like for the protection of users against medical needle points is known. After use, a medical needle may represent a substantial biohazard because of the possibility of AIDS or another bacterial or viral disease, which may be transmitted form a carrier to subsequent handlers of the needle by accidental needle stick. For example, various U.S. patents are known pertaining to sheaths for winged needles, such as Utterberg U.S. Pat. Nos. 5,112,311; 5,266,072; 5,290,264; 5,562,637; 5,704,924 and more.
Also, needle protector sheaths for wingless needles are known, such as Alverez U.S. Pat. No. 4,170,993, Magre et al. U.S. Pat. No. 4,935,012, Wanderer et al. U.S. Pat. No. 4,693,708, and Kasuya U.S. Pat. No. 4,985,020, among others.
A common design of needle for a blood collection set carries the needle on the end of a blood collection tube by means of a rubber hub which is shorter than the needle, but transversely enlarged compared with the width of the needle. Also, such a rubber hub is roughly in the form of a rectangular block, but with an irregular surface. The needle is without wings, so the technology of needle sheath designs which are used with winged needles is not usable here. Also, the prior art for shielding of wingless needles has not proven to be practical for the shielding of needle sets of the above described design.
By this invention, a needle tip protector tube can be provided for a medical fluid flow set in which a needle is carried with a transversely enlarged hub having an irregular surface and generally of a length shorter than that of the needle. Preferred embodiments of the protector tube of this invention can provide sealing to the tip of the needle, which is desired when the set carrying the needle is a blood set, to avoid the spilling of blood out of the needle tip. Also, the protector rube is inexpensive, simple, and reliable for use. Particularly, it may be carried on the tubing of the set and then advanced to surround and seal the needle tip when desired, so that one does not have to poke the needle through one end of the protector tube as part of the tube application process. That action has been a source of needle stick accidents.
DESCRIPTION OF THE INVENTION
By this invention, a needle point protection sheath is provided, which comprises a protector tube having a bore for completely receiving a hollow needle with its point positioned within the bore, and also for receiving the needle hub completely within the bore. The protector tube preferably carries a closure cap at one end thereof. At its other end, the protector tube has a retention member to engage an end of the hub, to prevent the hub from passing out of the other tube end.
The closure cap is attached to the protector tube at one end thereof by an integral plastic hinge. The cap also carries a manually grippable member extending outwardly from the side of the closure cap that is opposed to the hinge.
Thus, the protector tube may be strung upon tubing of the set that carries the needle with the set tubing extending through the bore of the protector tube. When its use is desired, the protector tube may be advanced along the set tubing until the attached hub and needle are enclosed in the protector tube. The retention member prevents the hub from passing out of the protector tube at one end, while at the other end the closure cap may then be closed, so that the tip of the needle is shielded.
The closure cap may carry a sleeve which projects inwardly of the protector tube when the cap is closed. The sleeve is closed at an inner end with a needle pierceable wall, if desired, whereby a tip of a needle carried within the tube can pierce the wall to be enclosed and at least to substantially seal the needle point in the sleeve as the cap is closed.
If desired, the inwardly projecting sleeve maybe filled with a needlepoint sealing mass carried on the closure cap such as rubber, latex, sealant, or the like, to sealingly receive a penetrating needle point of a needle carried in the tube when the cap is closed, to seal the end of the needle and prevent leakage. Alternatively, the sealing mass may be used apart from the inwardly projecting sleeve by simply attaching a self-supporting mass of rubber or other sealant material to the inner surface of the closure cap.
At the other end of the protector tube, the retention member may comprise a flange having an inwardly facing surface which is substantially perpendicular to the axis of the tube, and an outwardly facing surface defining an acute angle to the tube. Thus, a needle hub may be placed into the tube with its surfaces engaging the outwardly facing surface in the acute angle relationship, to spread the tube end and then to snap into a locked position which is created by the substantially perpendicular, inwardly facing surface. This perpendicular surface engages the end of the hub to prevent withdrawal of the same.
Alternatively, the retention member may comprise a plurality of plates attached to an interior surface of the protector tube, or the end thereof, and extending radially inwardly to define a restricted aperture of a size that permits flexible tubing attached to the needle hub to extend through the aperture with essentially no excess space. The plates are angled slightly in the direction of the protector tube longitudinal axis. Thus, the flexible tubing may slide in one direction through the restricted aperture, but is substantially prevented from sliding through the restricted aperture in the direction opposed to the one direction by flexing and gripping of the plates. The plates, while somewhat flexible, are rigid enough to provide this effect, similar in principle of operation in some ways to a Tinnerman washer.
The closure cap is preferably hinged to one end of the protector tube, and carries an attached finger grip, for example a ring. The closure cap preferably has a relatively thick outer wall to form a barrier to the pointed end of a needle enclosed in the interior of the protector tube.
The finger grip 36 is preferably positioned on the opposite side of the closure cap from the position of the hinge 21 that connects the closure cap 20 and the protection sheath 18. Thus, as shown in FIG. 3, finger grip ring 36 (FIG. 1) attached to closure cap 20, can extend outwardly substantially forward of the forward end of protector tube 18, and thus may serve as a retentive “anchor” to retain protector tube 18 in position as needle 14 and hub 16 are being withdrawn from the patient and into the protector tube, in a manner similar to that described for the anchor members disclosed in Utterberg, et al. U.S. Pat. No. 5,112,311.
If desired, the protector tube may have a longitudinal slot extending its entire length, to permit application of the needle guard laterally to the flexible tubing.
Preferably, a medical fluid and flow set is provided which comprises a flexible tube having a needle hub at an end thereof, and a hollow needle having a point carried by the hub. The protector tube of this invention maybe frustoconical or cylindrical, for example, surrounding at least one of the tube, hub, and needle depending upon its desired position, being slidingly movable along the set. The frustoconical protector tube has respective larger and smaller ends, with the large tube end facing in the same direction as the needle point. The smaller tube end is proportioned to surround and tightly squeeze against the hub, so that the protector tube resists withdrawal rearwardly along the set once it is pushed into a position of engagement with the hub. The protector tube is of a length to enclose the needle point when the smaller tube end encloses and squeezes the hub.
Generally, a closure cap is provided for the larger tube end, preferably a hinged cap.
Also, the protector tube preferably defines a retention member at its smaller end to prevent the hub from passing out of the smaller tube end. Thus, relative motion between the protector tube and the needle and hub can be basically eliminated when the hub is drawn up from a position back along the tubing of the set into engagement with the hub while enclosing the needle. The closure cap is closed, and the needle point is thus reliably enclosed so that subsequent handlers of the set are protected.
The particular design of retention member can be similar to those designs described above. Also, the previously described sleeve carried by an inner surface of the closure cap and projecting inwardly of the tube may be used to seal the needle tip in the manner previously described, as can the previously described needle point sealing mass of rubber or the like.
Thus, a simple needle point protection sheath comprising a protector tube is provided for reliable sealing of needles carried on blood collection and other sets which typically have a relatively enlarged hub relative to the needle and connected tube. The sheath is relatively inexpensive, providing reliable protection and also providing sealing of the point of the needle if desired.