GB2449491A

GB2449491A - Needle assembly with a locking protective sheath

Info

Publication number: GB2449491A
Application number: GB0710040A
Authority: GB
Inventors: Iden Shams
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-05-25
Filing date: 2007-05-25
Publication date: 2008-11-26
Also published as: GB0710040D0; WO2008146033A1

Abstract

A medical piercing needle assembly 1 comprises a piercing needle 2 slideably attached to a sheath 6; wherein the piercing needle 2 is moveable between two positions such that in its first position the piercing needle 2 is reversibly lockable such that its piercing end projects from said sheath to an extent to allow it, in use, to pierce an object; and such that in its second position the piercing needle 2 is irreversibly locked such that its piercing end is contained within said sheath. The piercing needle may be sharp at both ends.

Description

SAFETY NEEDLE

Field of the Invention

The invention relates to medical piercing needles such as hypodermic syringes, cannula introducers and needles for body piercing that are adapted to prevent needle-stick injuries.

Background and Prior Art Known to the Applicant

The problem of cross-infection in hospitals and other quasi-medical settings is well known, and of particular concern is the protection of medical staff and other personnel within the vicinity from so-called "needle-stick" injuries whereby a needle that has been in contact with e.g. a patient's blood may accidentally puncture the skin of another and cause cross-infection. Situations where there is a potential risk from this kind of injury include not only medical environments such as hospitals and doctors' surgeries, but also the increasingly popular body piercing salons where piercing needles may be used for the

introduction of body jewellery.

In the medical context, one particular procedure of concern is the fitting of intravenous cannulae. In this procedure, a flexible cannula is located over a piercing needle, in the form of a hypodermic needle; the needle and surrounding cannula is introduced into a vein until blood is seen to emerge from the end of the needle. The needle is then withdrawn, leaving the cannula located within a vein, thus providing convenient access for an attending clinician to take blood samples, administer intravenous medication and the like. When the needle is withdrawn from the cannula, it is clearly contaminated with blood and poses a risk for needle-stick injury to the clinician and others who may come into contact with the used device.

In some existing "safety cannulae", a sheath is provided into which a needle is automatically withdrawn (upon user-activation of a spring-driven mechanism) to encapsulate the sharp end of the needle. One drawback that arises from this device is that the sheath itself needs to be at least as long as the needle, leading to an overall excessively long device. Another drawback is the fear that activation of the spring-driven mechanism can cause the needle to be withdraw very rapidly into the sheath with the possibility that body fluids might be ejected as an aerosol from the end of the needle and the possible cross-infection that could ensue were this to occur. Thirdly, if a spring-actuated mechanism were to fail before the needle was fully retracted into the sheath, there would be nothing that an operator could do to safely ensure the sheathing of the needle.

In another procedure, one end of a double-ended hollow needle is introduced into the vein of a patient, and an evacuated -or partially evacuated -tube, sealed with a rubber membrane is pushed onto the other end of the needle. The needle punctures the membrane, and the vacuum causes blood to be drawn into the tube. This system is commonly available under the registered trade mark Vacutainer . Once the samples have been taken, the double-ended needle is removed from the patient's vein. During this procedure, there is risk of a needle-stick injury to the attending clinician, and to others in the disposal chain, once the needle is discarded.

In a yet further procedure, a standard syringe with a hypodermic needle may be used to draw a blood sample, or to introduce a medicament into a patient's body, such as into a vein. Again, once the needle is removed from the patient, there is a risk of needle-stick injury to the attending clinician, and to others in the disposal chain, once the needle is discarded.

It is therefore among the objects of the present invention to provide improved sheathing mechanisms for such needles.

Summary of the Invention

Accordingly, the invention provides a medical piercing needle assembly comprising: a piercing needle slideably attached to a sheath; wherein said piercing needle is moveable between two positions such that: in its first position, the piercing needle is reversibly lockable such that its piercing end projects from said sheath to an extent to allow it, in use, to pierce an object; and such that: in its second position, the piercing needle is irreversibly locked such that its piercing end is contained within said sheath.

Preferably, the piercing needle is hollow, and more preferably, the piercing needle comprises a hollow needle, sharp at both ends. This allows it to be used with "vacuum-mediated" blood sampling tubes.

In other preferred embodiments, said piercing needle is mountable on an interface unit comprising a connection port for connecting a syringe or the like, said connection port being in fluid communication with the bore of said needle; and said interface unit being slideably attached to the sheath. More preferably, said connection port is configured so as to not allow connection with a syringe or the like having a standard Luer configuration.

In these embodiments, it is further preferred that said piercing needle is permanently affixed to said interface unit.

In any embodiment of the invention it is particularly preferred that movement of the needle between the two said position is effected solely by manual intervention of a user, in use. Actuation of the device in this way is less likely to lead to splashing of contaminated fluids, and also allows more control, generally, by the operator.

Also included within the scope of the invention is a medical piercing needle assembly substantially as described herein, with reference to and as illustrated by any appropriate combination of the accompanying drawings.

Brief Description of the Drawing

The invention will be described with reference to the accompanying drawings in which: Figure 1 is an exploded perspective view of a first embodiment of the invention; Figures 2 and 3 are perspective views of a first embodiment of the invention with the needle in extended and retracted configurations respectively; Figure 4 is a perspective view of an inner sheath of the first embodiment of the invention; Figure 5 is a perspective view of a first embodiment of the invention in its retracted configuration; Figures 6 and 7 are cross-sectional views of a first embodiment of the invention showing the needle in extended and retracted configurations respectively; Figures 8 and 9 are perspective views of an outer sheath of a first embodiment of the present invention; Figures 10 and 11 are perspective views of end caps of a first embodiment of the present invention; Figure 12 is a perspective view of an actuating member of a first and second embodiment of the present invention; Figure 13 is a perspective view of a second embodiment of the invention showing a needle in its extended configuration; Figure 14 is a perspective view of an interface unit of a second embodiment of the invention together with an actuating member; Figure 15 is a perspective view showing an interface unit and actuating member of a second embodiment of the invention connected to a syringe; Figure 16 is a perspective view of a second embodiment of the invention with a syringe, with its needle in an extended configuration; and Figure 17 is a perspective, cut-away view of a second embodiment of the invention showing the needle in its retracted configuration.

Description of Preferred Embodiments

Figure I illustrates, in exploded perspective view, an embodiment of the invention, generally indicated by I, for use with a double-ended piercing needle. The assembly comprises a double-ended needle 2 that is hollow, and sharp at both ends. This needle 2 is mounted onto an inner sheath 3 by means of a collar 4 that mates with a receiving portion 5 on the inner sheath 3.

When assembled, the inner sheath and needle sit within an outer sheath 6. The inner and outer sheaths are so sized as to allow the inner sheath to slide within the bore of the outer sheath 6. The outer sheath 6 is configured to have a hole 7 through which the needle 2 can protrude to allow access to the needle 2.

The inner sheath 3 is furnished with one part of a reversible locking mechanism comprising a resiliently deformable hook 8 that is configured to engage with a corresponding hook-receiving slot 9 located at one end of the outer sheath 6. Along the length of the outer sheath 6 is a slot 10 on either side of which are guide rails 11. When assembled, an actuating member 12 slides along the guides 11 and interacts with the inner sheath 3 and an irreversible locking mechanism connected to the outer sheath 6. The irreversible locking mechanism comprises a second reversibly deformable hook member 13 that locks into a corresponding opening 34 formed in an end-cap 15 that fits on the end of the outer sheath 6. Operation of the locking mechanisms will be described more fully below.

Figure 2 illustrates, again in perspective view, an embodiment of the invention, generally indicated by 1, in its assembled form, and where the piercing needle 2 is moved to, and reversibly locked in, a position such that the piercing needle 2 projects from the outer sheath 6 to allow it to pierce an object, such as the vein of a patient. It can be seen that in this configuration, a hook member 8 of the inner sheath 3 is engaged with the hook-receiving slot 9 in the outer sheath, thus holding the needle 2 in this extended configuration. A hook-actuating portion 14 of the actuating member 12 rests on a portion of the hook member 8. The hook member 8, in its "at rest" configuration is biased to engage in the hook-receiving slot 9 to hold the needle in the position illustrated. In use, when it is required to retract the needle 2 into its sheathed configuration, the front-most portion of the actuating member 12 (i.e. the portion closest to the hook member 8) may be depressed by a user to deform the hook member 8 such that it disengages from the hook-receiving slot 9. The actuating member 12 may then be drawn back along the slot 10 and guides 11 towards the end cap 15 of the device. Sheath-engaging portions 16 of the actuating member 12 engage with abutment surfaces 17 on the inner sheath 3 and pull the sheath, and attached needle 2 into the outer sheath 6 and into the configuration illustrated in figure 3. In this configuration, the needle 2 is safely contained within the envelope of the outer sheath 3. When in this configuration, the second hook member 13 of the actuating member 12 is irreversibly locked into the opening 34 in the end cap 15. This figure, also illustrates a further feature of the inner sheath 3, in that it has a chamfered opening 17 to facilitate, in use the introduction of an evacuated, membrane-sealed collection tube to be pierced by one end of the double-ended needle 2.

Figure 4 illustrates for clarity, the structure of the inner sheath 3 and showing more clearly the reversibly-deformable hook member 8 and the abutment surfaces 17.

Figures 6 and 7 show, in cross-section view a first embodiment of the device with the needle in its extended, and retracted configurations respectively.

Figures 8 and 9 show, in perspective view, the two ends of the outer sheath 6. The figures illustrate the location of the hook-receiving slot 9 to receive the hook member 8, the elongate slot 10 and the two guides 11. Also illustrated, are two lug-engaging slots 18 that engage, irreversibly, with corresponding lugs 19 on the end cap 15 (not illustrated).

Figures 10 and I I show, in perspective view, each side of the end cap 15 that fits on the end of the outer sheath 6. Illustrated in these figures is the opening 34 into which the second hook member 13 irreversibly locks, to secure the needle 2 in its sheathed configuration. The figures also illustrate that the cap 15 is provided with two wings 20 to facilitate the manipulation of the device by a user, in use.

Figure 12 illustrates, in perspective view, details of the actuating member 12. The figure shows the configuration of the actuating portion 14 that engages with the first hook member 8, the two engaging portions 16 that engage with the abutment surfaces 17 on the inner sheath 3, and the second hook member 13 that engages with the opening 34 in the end cap 15. Also provided in the actuating member 12 are two slots 21 that engage with the corresponding two guides 11 in the outer sheath 6. Finally, a ridged thumb-engaging portion 22 is provided to facilitate withdrawal of the needle into the outer sheath 6 by a user, in use.

A second embodiment of the invention is illustrated, in perspective view in figure 13. In this embodiment, a hypodermic needle 2 is mounted onto an interface unit 23 that slides within the wall of an outer sheath 6. Details of the interface unit 23 will be described below. This embodiment also has an actuating member 12 that slides within a slot 10 between two guides 11 located along the length of the outer sheath.

Figure 14 shows, in perspective view, an interface unit 23 forming part of this embodiment. At one end of the interface unit is a male Luer connector 24 on which is mounted a hypodermic needle 2. At the other end of the interface unit 23 is a connection 25 in fluid communication with the male Luer connector 24. Integral to the interface unit 23 is a resiliently-deformable hook member 8 that interacts, in use, with the outer sheath 6 of the device to be described in more detail below. In particularly preferred embodiments of the device, the connection port 25 is configured so that it is unable to be connected to a connection having a standard Luer tapered design (i.e. it will not connect to a connector following the standard ISO 594-1:1986). For example, the syringe and connection port could have the shape and taper angle of a standard Luer fitting, but be constructed to be of a larger size. In this way, a syringe that has been used with the device cannot subsequently be connected to a standard Luer fitting needle, so reducing the chance of cross-infection from one patient to another.

Also illustrated in figure 14 is an actuating member 12 of similar configuration to that described in relation to the forgoing embodiment. The actuating member 12 has an actuating portion 14 that sits against the hook member 8. It also has a pair of engaging portions 16 and a second hook member 13 to irreversibly engage in a slot on the outer sheath.

Figure 15 shows, again in perspective view, the interface member 23 with its male Luer connector 24 attached to a needle 2. The figure illustrates how, in use, a syringe 26 may be connected to the interface unit 23 by means of the connection port 25 (not visible).

The outer sheath 6 is not illustrated in figure 15, for sake of clarity.

Figure 16 illustrates, in perspective view, the embodiment of the invention, with a syringe in place. The device is in its first configuration, with the needle protruding from the outer sheath 6. The needle is held in this position by the hook member 8 of the actuating member 12 engaging in a corresponding hook-receiving slot 9 in the outer sheath 6. Also illustrated in this figure is the slot 10 and the guides 11 along which the actuating member 12 may be slid, in a way analogous to the operation of the first embodiment.

In an analogous way to the operation of the first embodiment of the invention, when use of the needle has been completed, a user may press down on the actuating member 12, so pushing the actuating portion 14 against the deformable hook 8, so releasing it from the hook-receiving slot 9. The actuating member 12 may then be used to retract the needle and interface member 23 within the envelope of the outer sheath 6.

Figure 17 illustrates, in perspective view, this embodiment of the invention in its retracted configuration, and in which the needle 2 is contained within the envelope of the outer sheath 6. A portion of the outer sheath has been cut away to enable the needle and interface unit to be seen. In this configuration, the second hook member 13 has engaged, irreversibly, in a opening 34 in the outer sheath 6, again in a way entirely analogous to that described for the first embodiment, so preventing needle-stick injury to the operator and others.

Claims

I. A medical piercing needle assembly comprising: a piercing needle slideably attached to a sheath; wherein said piercing needle is moveable between two positions such that: in its first position, the piercing needle is reversibly lockable such that its piercing end projects from said sheath to an extent to allow it, in use, to pierce an object; and such that: in its second position, the piercing needle is irreversibly locked such that its piercing end is contained within said sheath.
2. An assembly according to claim 1 wherein said piercing needle is hollow.
3. An assembly according to claim 2 wherein said piercing needle comprises a hollow needle, sharp at both ends.
4. An assembly according to Claim 2 wherein said piercing needle is mountable on an interface unit comprising a connection port for connecting a syringe or the like, said connection port being in fluid communication with the bore of said needle; and said interface unit being slideably attached to the sheath.
5. An assembly according to Claim 4 wherein said connection port is configured so as to not allow connection with a syringe or the like having a standard Luer configuration.
6. An assembly according to either of claims 4 or 5 wherein said piercing needle is permanently affixed to said interface unit.
7. An assembly according to any preceding claim wherein movement of the needle between the two said position is effected solely by manual intervention of a user, in use.
8. A medical piercing needle assembly substantially as described herein, with reference to and as illustrated by any appropriate combination of the accompanying drawings.