GB2259254A

GB2259254A - Side-entry sheaths for needles or sharp instruments

Info

Publication number: GB2259254A
Application number: GB9217968A
Authority: GB
Inventors: Arthur Hugh Lister
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-09-04
Filing date: 1992-08-24
Publication date: 1993-03-10
Also published as: GB9217968D0

Abstract

It is important to protect personnel from injury by needles contaminated with blood. Two designs of sheath are presented which afford protection to the fingers whilst re-sheathing a needle in the usual way (Figs 1 & 2). Two designs are presented of a sheath that pivots laterally so that the sheath does not interfere with the use of the needle but may be flicked back over the needle safely and easily (Figs 3 & 4). A design of sheath is offered which whilst being less secure is designed to hug the body of a narrow syringe when the needle is exposed. This design may have application in dentistry where space is limited (Fig 5). A design is offered for the "butterfly" (Fig 6). Finally 3 designs are offered the first of which is a simple plastic moulding. It clicks onto a modified noodle hub in such a way that it is normally held guarding the needle but may be pivoted out of the way and flicked back over the needle after use (Fig 7). The last two designs are modifications which offer more security at the expense of being more complex (Figs 8 & 9). <IMAGE>

Description

SHEATHS FOR SHARP INSTRUMENTS AND NEEDLES Injury by sharp instrument or needle is always to be avoided. If it is contaminated with blood then the risk of injury is much more serious. Because it is possible to injure oneself re-sheathing an instrument such as a needle many authorities issue a policy of no re-sheathing. An unsheathed instrument is still a hazard and may cause injury being transferred to a suitable disposal bin.

It is necessary to be able to expose and re-sheath a sharp instrument or needle at will. It is necessary to be able to fit most types of needle to most types of syringe.

It is also necessary to be able to remove a needle from a syringe and replace it without risk of injury, contamination of the needle or of the solution within.

A typical needle consists of a hollow tube with a sharp bevelled distal end. At the proximal end there is a hub which usually has a female Luer taper. This hub may have ears which engage in an internal double-start thread which surrounds the male Luer taper. This arrangement is known as a Luer-lock. Splines are usually provided onthe hub which engage with internal splines in the sheath. This enables the needle to be twisted off a taper by gripping the sheath.

A type of needle designed to be left in situ for short periods is provided with flaps for fixing purposes.

These flaps give this type of needle the name "butterfly".

The access port is on the end of a short piece of tubing.

This allows handling of the port without disturbing the needle at its site of insertion.

Any needle can damage its site of insertion. If more secure intra-vascular access is required it is customary to use a plastic cannula. This is is inserted with a needle which is then withdrawn. Such a cannula has its own hub which may possess a separate access port either built in or on the end of a short piece of tubing. As such a cannula fits around the outside of a needle, it will be shorter than the needle.

For inserting a longer or more complex device it is customary to either insert the tube (commonly known as a catheter) up the inside of the needle which is then withdrawn down the outside of the catheter. Such a catheter has to have an access port fitted afterwards. Alternatively a soft wire is threaded up the needle which is then withdrawn. The catheter is then passed over the guide wire which is finally withdrawn. This method is known as the Seldinger technique.

For the more complicated procedures a sterile work surface is provided on which instruments and needles are placed. They can then be disposed of into a suitable container ina non-hazardous manner.

The more common place procedures such as withdrawal of blood, drawing up of drugs, injections and intravenous cannulations do not usually have this facility.

Risk of injury to personnel is greater. If the situation is urgent then the risks are greater still.

According to the present invention several designs are presented. The first two allow re-sheathing of a needle in a safe manner. Because accidents will always happen and many authorities will insist of a policy of no re-sheathing further designs are presented which show the sheath attached to the needle. This allows instant re-sheathing without risk which will be workable in the vast majority of procedures.

The sheath is designed to uncover the needle by turning up through 90-120 degrees so that it can lie almost parallel to the bevel. In this way the sheath does not interfere with the use of the needle.

A deficiency is provided proximally which allows clearance of the hub of a cannula with its access port.

A design is presented which can fold back and lie close to the body of a narrow syringe. This may have a use in dentistry where space is restricted.

A design is presented for the "butterfly".

Finally a design is presented which is the simplest moulding, fits a modified hub and provides effortless covering of the needle.

Fig t shows a needle sheath with a flange t at its proximal end. There is a deficiency 2 with guide plates 3.

The sheath is gripped between finger and thumb. With digits protected the operator places the needle in the deficiency 2 before sliding it distally to enclose the sharp end. The hub is gripped in the flange end by a courser taper than the Luer taper. Splines are provided so that the needle can be twisted off and on a Luer taper. Enough of the hub must protrude proximally to allow engagement of a Luer-lock and removal of the needle from the sheath by hand. This useful and sometimes necessary.

Fig 2 shows two views of an embodiment which allows encapsulation of the whole needle. It consists of two halves of a sheath hinged together longitudinally. The top view shows the device closed and the bottom view shows the device opened. There are a flange 5 and guide-plates 6 which serve the same protective purpose of the digits as in the embodiment shown in fig 1. Plates 7 at the proximal end allow the sheath to be opened. A catch 8 holds the sheath shut. As in the embodiment shown in fig 1, facility is provided to hold the the hub safely but in such a manner that it can be twisted off and on a Luer-lock taper or removed by hand.

Fig 3 shows an embodiment which is fixed to the needle. There is a top plate 9 with a deficiency 10 to clear the hub of a cannula (not shown). The sides ll which include overlapping bottom plates 12 and ends 13 are hinged longitudinally along axes 14. These allow the needle to be uncovered and hinge 15 to become a straight line. Hinge 15 allows the sheath assembly to pivot up as shown. It is convenient and sometimes very useful to be able to expose the needle with one hand. There is provided a safety catch 16 which must be pushed down. This allows plate 17 to be pressed down which draws up the sides 11 and springs 18 moulded across hinge 15 operate it, pulling the sheath assembly into the position shown.After use the sheath may be pushed back over the needle 19. Springs 20 moulded in ensure that the sides 11 snap down over the needle 19.

Fig 4 shows two views of another embodiment which is hinged onto the needle hub. The top view shows the needle covered and the bottom view shows the needle exposed. the sheath 21 has a deficiency 22. Squeezing plates 23 medially pushes the sheath distally so that the deficiency 22 can clear the needle 27. Arms 24 sliding in grooves 25 do not allow the hinge 26 to operate until the deficiency 22 is clear of the needle 27. Also arms 24 hold the sheath distally when it is hinged up so that only when it is pushed down does it spring back over the needle 27. This design may be operated with one hand. The dexterity required avoids inadvertent exposure. The space between plates 23 and 24 allows room for the hub of a cannula.

Fig 5 shows three views of an embodiment which can be folded back on itself and made to hug the body of a thin syringe to which it is attached (not shown). The top view shows the needle covered, the middle view shows hinge 29 made into a straight line and the bottom view shows the device folded back on itself. Syringes are too variable in shape for this design to be used generally, but it may have application where space is limited such as dentistry. As shown the sides do not overlap and there are no ends. This simple design does not have the security of other embodiments. The sheath is a triangular tube. Obviously when the sheath is open and folded back it is possible to contaminate the needle-side surface of the sheath.

Fig 6 shows a modification of the "butterfly". The flaps 29 may be unfolded and used to enclose the sharp end of the needle 30 as shown.

Fig 7 shows a side elevation uppermost and a plan lowermost of a needle 35, hub 31 and sheath 36. The hub possesses pegs 32 and studs 33. The sheath 36 may be engaged on these studs by the manufacturer. At use the ears 37 may be sprung off the pegs 32 to allow the sheath to pivot about the studs 33 in the direction shown by arrow 38. After use the sheath 36 may be pushed back over the needle 35 and the pegs 32 hold it in position.

It may be seen that the sheath 36 is a simple moulding. It may be attached to the hub by a moulded hinge instead of the studs 33. This method is not illustrated.

The sheath may have a roof 39. The deficiency in the roof between it and the pivot allows for the body of a cannula with its injection port if the needle is used to introduce a cannula.

The sheath 36 has no floor to allow egress of the needle 35 when the sheath is pivoted up. This is safe provided the sheath is made of reasonably rigid material.

If it is required for the needle to be boxed in by a floor a possible arrangement is shown in fig 8. The upper figures shows a needle 40 and sheath 41 broadly similiar to fig 7 but the studs 42 and pegs 43 are positioned differently.

The lower figures show section X-X. Springing the ears 44 apart allows the sheath to pivot about studs 42 in the direction shown by arrow 45 and distorts the sheath enough to make a gap 46 in the floor. This allows egress of the needle 40.

An alternative way of having a floor to the sheath is to utilise a moulded hinge. Fig 9 shows an embodiment similiar to fig 7 but with a floor 47 to the sheath 48. The hub 49 has a step 50 protruding from it which is shown hatched in all the other views of fig 9. The lower views show section Z-Z. When the sheath is pivoted up in the direction shown by arrow 51 the step 50 interferes with the floor 47 of the sheath. This floor is split and hinged at 52. The floor is forced to open and allow egress of the needle 53.

Claims

CLAIMS 1) A sheath for a sharp instrument, comprising attachment means for securing the sheath to the instrument and enabling a movable part of the sheath to move relatively to the instrument between an enclosing position and an exposing position, the said sheath part having a lateral opening enabling entry thereto and egress therefrom of at least the sharp part of said instrument in the course of said relative motion.
23 A sheath according to Claim 1, wherein said attachment means are pivotally connected to said movable part.
3) A sheath according to Claim 1 or 2, wherein said lateral opening is defined between relatively separable parts of the sheath adapted to move to close said opening in said enclosing position of the sheath.
4) A sheath according to Claim 3, wherein said movable part of the sheath comprises a plurality of longitudinally hinged parts biassed to an enclosing configuration.
5) A sheath according to Claim 4, wherein said movable part comprises a sheet having lines defining hinges.
6) A sheath according to Claim 1 or 2 wherein said attachment means provide for longitudinal relative motion between the movable part and the instrument.
7) A sheath according to Claims 1 and 2 means being provided on or close to the hub of a needle, or the shank or root of a sharp instrument to hold the sheath in a firm but releasable manner in either the enclosing or exposing position.
8) A sheath for a sharp instrument, substantially as described with reference to and as shown in Figure 1 of the drawings.
9) A sheath for a sharp instrument, substantially as described with reference to and as shown in Figure 2 of the drawings.
lO) A sheath for a sharp instrument, substantially as described with reference to and as shown in Figure 3 of the drawings.
11) A sheath for a sharp instrument, substantially as described with reference to and as shown in Figure 4 of the drawings.
12) A sheath for a sharp instrument, substantially as described with reference to and as shown in Figure 5 of the drawings.
13) A sheath for a sharp instrument, substantially as described with reference to and as shown in Figure 6 of the drawings.
14) A sheath for a sharp instrument, substantially as described with reference to and as shown in Figure 7 of the drawings.
15) A sheath for a sharp instrument, substantially as described with reference to and as shown in Figure 8 of the drawings.
16) Every novel feature and combination of features disclosed herein.