Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to the safe disposal of medical
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needles, for, example syringe needles and cannulation instruments commonly
', used in the health care field.
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Needles used with syringes to draw body fluids or gases, to inject
various materials into pa~ients, or in the insertion of cannula, are commonly
contaminated with infectious agents from the patients. Upon withdrawal of
- ~j such a needle, the health care professional is left with the task of preventing
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, the exposed needle from poking him or herself or those around them. Such a
poke may transfer the infectious agent and the disease it causes to the health
care worker.
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~ A protective cap is the protection commonly provided against the
,~ above risks. As such the location of the cap mustbe kept in mind and secured
-~, while performing the procedure. Location of the cap may change for various
, reasons. It may fall on the floor or become lost in the patient's bed sheets.
These delays increase the time the contaminated needle is exposed and
~ therefore the risk of poke increases. Also the need to move around with the
`,'.2 contaminated needle in hand to retrieve the cap increases the risk of poke. It
, also follows logicaliy that to retrieve a cap requires the eyes of the person
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holding the needle to be removed from the needle, again, increasing chance of
mishap.
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If cap retrieval is unsuccessful or impractical for any reason, other
methods of disposal are in place but again do not seem to be without
significant risk of needle poke. One such method is to have a cork board or the
like attached to the needle tray for such needles to be removed by hand and
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stuck into. This may leave a few uncapped contaminated needles on the tray
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j~, which may fall out and, even if they remain, they must ultimately be handled ~
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again for eventual disposal, again, increasing risk of needle poke. Another
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method in place for disposal of uncapped needles is the sharps container
which is used for eventual disposal of all sharp instruments capped or
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-~i uncapped. The container may be some distance away, even across the room,
. 3 once again increasing movement with the contaminated needle and increasing
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- risk of poke.
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Even if cap retrieval is successful and one intends to use the
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.3 supplied cap for recapping the needle there are real risks. Although one should
t never recap with two hands i.e. bring the needle towards the opposite hand
while holding the cap, this seems to be the instinctual method unless a
conscious effort is made to use the safer and currently taught one-handed
method i.e. Ieaving the cap on another surface and bringing the needle to it.
Once the needle is inside the cap, it is pushed~down into the cap with the
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supporting surface as a stabilizer. This one-handed method is awkward at best
and still has many of the aforesaid risks involved with it.
i In the placement of a cannula, for example for an intravenous
. i; line, the metal support needle, known as a trocar, used to place the cannula is
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yet another contaminated and sharp by-product left in the hand of the person
~; performing the procedure. Such trocars are once again equipped only with a
similar cap, leading to all of the above risk factors.
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i~ The present invention is concerned with a novel apparatus for mitigating the above problems.
According to the present invention, there is provided a prot~ctive
apparatus for use with a medical needle of the type having a base and an
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p~i, elongate shank with a penetrating point, said apparatus comprising:
a sheath configured to surround the needle;
mounting means for mounting the sheath on the needle for
movement along the needle from a use position with the needle projecting
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beyond an end of the sheath to a protective position surrounding and
` ~ extending beyond the needle point; and
retaining means for retaining the sheath in the protective position.
All of the risk factors related to the disposal of the contaminated
~i ~ needles and other cannulation devices with a simple one-cap/recap system can
i be greatly reduced if not eliminated with the additional sliding protective
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:i~3 sheath on the instrumentation. The cap supplied with the needle may be
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discarded upon uncapping. The protective sheath may slide into place
simultaneously with the withdrawal of the needle from the patient. Therefore
the health care worker is never left holding an unprotected contaminated
i, instrument. If the needle falls on the floor at this point it poses no threat as the
~, sheath is locked in place by the retaining means. ~The health care worker never
-~, removes his/her eyes from the procedure until the sheath is in place. To put
the sheath in place the user never has an unprotected hand near the sharp end
of the instrument.
The sheath mounting means may be a component that mounts
between the needle base and the syringe or withdrawal handle on which it is
mounted. Alternatively, the mounting means may be made as one part with
the needle base.
The retaining means may be a ratchet extending along the sheath,
and a pawl on the mounting means, an arrangement which allows the sheath,i
to move only in the direction of the tip of the instrument.
In the accompanying drawings, which illustrate the conventional
prior art and exemplary embodiments of the invention:
Figures 1, 2 and 3 illustrate the prior art needle capping system;
` ' Figure 4 is a side view of an embodiment of the present invention
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~ ~ as applied to a syringe and needle;
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Figure 5 is a cross section of the apparatus illustrated in Figure 4;
Figure 6 is an isometric view of the sheath component of theapparatus of Figure 4;
Figure 7 is an end view of the sheath; -
Figure 8 is an isometric view of the mounting component of the
apparatus;
Figure 9 is a detail view of a retainer ratchet;
Figures 10, 1 1 and 12. which appear on the same sheet as
Figures 1, 2 and 3, illustrate a prior art cannula and trocar capping system;
Figure 13 illustrates an embodiment of the invention for use with
a cannula and trocar in a disassembled condition;
. Figure 14 is a view of the embodirn~ent of Figure 13 prepared for
ti use;
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Figure 15 is a view like Figure 14 with the trocar sheathed; and
Fi~ure 16 is a side view, partly in section of a further embodiment
of the invention applied to a syringe and needle.
Referring to the accompanying drawings, Figures 1, 2 and 3
illustrate a prior art needle capping system for a syringe. This includes a
syringe 10 of a conventional sort and the usual commercially supplied needle
and cap assembly 12. The end of the syringe has a spigot 14 surrounded by a
threaded cylindrical sleeve 16. The needle 18 of the assernbly 12 has a base
20 that engages on the spigot, inside the sleeve 16. This yields the assembly
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~,' of a syringe and a capped needle as illustrated in Figure 2. For use, the cap
~`~ 22 is pulled off the needle 18 and is, in theory, set aside for recapping the
;, needle when it has bsen used. As noted above, there are a nuimber of
uncertainties in this process. The exposed needle constitutes a hazard.
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A protective sheath apparatus for resolving this problem is
illustrated in Figures 4 through 9. The protective sheath apparatus includes a
~ cylindrical sheath 26 that fits over the syringe in the use position illustrated in
- Figure 4 and may be pushed forward to a protective position surrounding the
needle 18 and projecting beyond its sharp penetrating end. The apparatus also
; includes a mountin0 component 28 that is positioned within the sheath and
mounts the sheath on the syringe and needle combination.
Inside the sheath are two diametrically opposed T-shaped tracks
30. These have, on their inner faces, ratchets 32 that extend substantially the
- ~ full length of the tracks. Adjacent the bottom end of each track, also on the
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- inner face, is a boss 34 acting as a stop to limit movement of the sheath on
the mounting component.
The mounting component 28 includes a circular flange 36 with
two, diametrically opposed T-slots 38. These slots engage slidably on tha T-
tracks 30 to guide the movement of the sheath on the mounting component
28. Within each T-slot, along the radial innermost side, is a pawl 40 that
engages the associated ratchet and will slide along that ratchet towards the
stop boss 34. The arrangement is such howevar, that the reverse movement
of the pawl along the ratchet is not possible.
On the top surface of the flange 36 are a spi00t 42 and a sleeve
44 that correspond to the spigot 14 and sleeve 16 on the end of the syringe.
Thus, the base 20 of the needle 18 may be coupled to the spigot 42 in the
same way as it may be coupled to the spigot 14 on the syringe. On the
bottom of the flange 36 is a base component 46 that corresponds in
configuration to the base 20 of the needle 18 so that the base 46 may be ;~ ;~connected to the spigot 14 on the end of the syringe.
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In use, the conventional syringe 10 is connected to the mounting
component 28 of the protective sheath apparatus and the conventional needle
and cap assembly 12 is also connected to the mounting component 28. The
protective sheath is in a retracted or use position surrounding the barrel of the
syringe. When it is desired to use the syringe, the cap 22 of the needle is
removed and may be discarded. Following use, the syringe is withdrawn,
while the sheath is held in place. The sheath 26 thus moves forwards along
the syringe until the pawl 40 engages the stop boss 34. At this point, the
sheath surrounds and projects beyond the sharp end of the needle 18 and
cannot be retracted from that position. The needle is thus prevented from
coming into contac~ with other objects. For disposal, the needle and sheath
may be removed as a unit from the syringe.
Another embodiment of th0 prior art is illustrated in Figures 10,
11 and 12. This is a cannula assembly 48 that includes a hollow cannula 50 a
supporting trocar or needle 52 with a sharp leading end that projects out of
the cannula for insertion purposes, and a base 54 on the trocar that is used to
withdraw it from the cannula. A protective cap 56 is positioned over the
cannula and trocar. When the cannula is to be inserted, the cap is
removed, as shown in Figure 11. After insertion, the trocar 52 is withdrawn
from the cannula as illustrated in Figure 12. This leaves the exposed,
contaminated trocar 52 for disposal.
An embodiment of the invention usefut for this purpose is
illustrated in Figures 13, 14 and 15.
The protective sheath apparatus 58 of this embodiment includes a
sheath 60 that includes internal T-tracks, ratchets and stops that are of the
same configuration as the T-tracks 30, ratchets 32 and stops 34 of the
previously described embodiment. In this case, the sheath is somewhat longer
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to accommodate the longer length of the cannula assembly. A mounting
component 62 slides in the sheath. It has a flange 64 with T-slots and pawls
like the T-slots 38 and pawls 40 of the previously described embodiment. The
top of the mounting component 62 has at the centre a resilient rubber spigot
66 and a resilient rubber sleeve 68 that engage in the recess in the base of
the trocar and grip its outside periphery.
Secured to the bottom side of the mounting component 62 is an
elon~ate handle 70 that extends from the component through the protective
sheath 60 so that the trocar may readily be withdrawn into the sheath.
In use of this sheath assembly, the complete cannula and trocar
assembly is fitted onto the top of the mounting component, with the protective
sheath fully withdrawn. The cap 56 is then remo~ved and the cannula inserted.
Then, by gripping the handle 70 and the sheath 60, the trocar may be
withdrawn into the sheath and released from the cannula in a fully protected
position. ~ ~-
A further embodiment of the invention, also for use wi~h a
syringe, is illustrated in Figure 16. This embodiment is similar to the
embodiment of Figures 4 throu~h 9, but in this case the needle base and the
mounting component are integrated so that the user will have only two
components to assemble, the conventional syringe and the needle and sheath
assembly 74. The base 76 of the needle carries a flange 78 like the flange 36 -~
of the first embodiment. ;
A similar embodiment may be constructed for use with a cannula
assembly, with the trocar, mounting component and handle all integrated. It is
also possible to make embodiments for use with cannulae where various of the
parts are separate and attachable.
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While certain embodiments of the present invention have been
described in the foregoing, it is to be understood that other embodiments are
possible without departing from the invention and are intended to be included
within the scope of the appended claims.
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