IV catheter abstract
A safety IV catheter includes an end cap or guard and a disc-shaped
lock plate having an opening through which the needle passes. One
end of an actuator member passes through a second off-center opening
in the lock plate and its other end passes through a flange fitted
about the needle hub. In the prepared or ready position of the catheter,
the guard is mounted about the distal end of the needle hub. As
the needle is retracted to the activated position, the needle tip
is received within the needle guard and the lost motion of the actuator
member is taken up by the engagement of the needle hub and the lower
end of the actuator member. This, in turn, causes the lock plate
to be canted or rocked at an angle about the distal end of the needle
to grip and lock the needle tip within the needle guard and to prevent
further axial movement of the needle.
IV catheter claims
What is claimed is:
1. A catheter comprising a needle, a needle hub affixed to one
end of said needle, a catheter hub, a needle guard intermediate
and releasably secured to said needle hub and said catheter hub,
said needle guard comprising locking means having an opening for
freely receiving the shaft of said needle when said catheter is
in a ready condition, said needle hub being movable axially away
from said needle guard to an activated position in which the tip
of said needle is received within said needle guard, and actuating
means in engagement with said locking means, said needle hub including
means for operatively engaging said actuating means when said needle
hub is moved to its activated position, thereby to cause said actuating
means to move said locking means to a locking position in which
it contacts the shaft of said needle at said opening, thereby to
restrict further axial movement of said needle, said actuating means
including lost motion means extending between said locking means
and said needle hub and capable of relative displacement with respect
to said needle hub as the latter is moved toward its said activated
position, said lost motion means comprising an actuator having an
upper end engaging said needle guard when the latter is in its ready
position, said locking means further including a lock plate having
a second opening radially spaced from said first opening for receiving
the upper end of said actuator.
2. The catheter of claim 1 in which said needle guard includes
a split distal end adapted to be snugly but releasably placed in
the luer opening of said catheter hub.
3. The catheter of claim 1 in which said needle guard includes
a projection positioned to exert a force on said lock plate to retain
said lock plate means in locking engagement with the needle shaft
when a force is applied to said needle guard.
4. The catheter of claim 3 in which said needle hub includes a
peripheral flange for engaging the lower end of said actuator when
said needle hub is in its said retracted activated position.
5. The catheter of claim 4 in which said actuator comprises a
at each of its ends for respectively engaging its upper end to said
needle guard and for engaging said needle hub when the latter is
moved to its retracted activated position.
6. The catheter of claim 3 in which said needle hub includes a
peripheral flange for engaging the lower end of said actuating means
when said needle hub is in its said retracted activated position.
7. The catheter of claim 4 in which said actuating means comprises
means bead at each of its ends for respectively engaging its upper
end to said needle guard and for engaging said needle hub when the
latter is moved to its retracted activated position.
8. The catheter of claim 1 in which said needle guard includes
a split distal end adapted to be snugly but releasably placed in
the luer opening of said catheter hub.
9. The catheter of claim 8 in which said needle guard includes
a projection positioned to exert a force on said locking means to
retain said locking means in locking engagement with the needle
shaft when a force is applied to said needle guard.
10. The catheter of claim 9 in which said needle hub includes
a peripheral flange for engaging the lower end of said actuator
when said needle hub is in its said retracted activated position.
11. The catheter of claim 10 in which said actuator comprises
means at each of its ends for respectively engaging its upper end
to said needle guard and for engaging said needle hub when the latter
is moved to its retracted activated position.
12. The catheter of claim 1 in which said needle guard includes
a projection positioned to exert a force on said locking means to
retain said locking means in locking engagement with the needle
shaft when a force is applied to said needle guard.
13. The catheter of claim 12 in which said needle hub includes
a peripheral flange for engaging the lower end of said actuator
when said needle hub is in its said retracted activated position.
14. The catheter of claim 1 in which said needle guard includes
a member providing an offset fulcrum, said locking means being pivotable
about said fulcrum to its said locking position.
15. A catheter comprising a needle, a needle hub affixed to one
end of said needle, a catheter hub, a needle guard intermediate
and releasably secured to said needle hub and said catheter hub,
said needle guard comprising locking means having an opening for
freely receiving the shaft of said needle when said catheter is
in a ready condition, said needle hub being movable axially away
from said needle guard to an activated position in which the tip
of said needle is received within said needle guard, and actuating
means in engagement with said locking means, said needle hub including
means for operatively engaging said actuating means when said needle
hub is moved to its activated position, thereby to cause said actuating
means to move said locking means to a locking position in which
it contacts the shaft of said needle at said opening, thereby to
restrict further axial movement of said needle, said actuating means
comprising an upper end engaging said needle guard when the latter
is in its said ready position, said locking means including a lock
plate having a second opening radially spaced from said first opening
for receiving the upper end of said actuating means.
16. The catheter of claim 15 in which said needle guard includes
a projection positioned to exert a force on said locking means to
retain said locking means in locking engagement with the needle
shaft when a force is applied to said needle guard.
17. The catheter of claim 16 in which said needle guard includes
a member providing an offset fulcrum, said locking means being pivotable
about said fulcrum to its said locking position.
IV catheter description
TECHNICAL FIELD
This invention relates generally to intravenous (IV) catheters,
and, in particular, to a safety IV catheter in which the needle
tip is automatically covered and locked in a protected condition
after needle withdrawal to prevent the health-care worker from making
accidental contact with the needle tip.
BACKGROUND OF THE INVENTION
I.V. catheters are primarily used to administer fluids, sometimes
containing medications, directly into a patient's vascular system.
The catheter is inserted into a patient's vein by a health care
worker by using a handheld placement device that includes a sharp
tip needle. The needle is positioned in the interior hollow portion
of the catheter with its tip extended slightly beyond the edge of
the catheter. The end of the apparatus opposite the needle tip is
made up of the needle connected to a needle hub which is capable
of being held by the health care worker during the insertion procedure.
The insertion procedure contains four basic steps: (1) the health
care worker inserts the needle and catheter together into the patient's
vein; (2) after insertion into the vein with the needle point, the
catheter is forwarded into the vein of the patient by the health
care worker pushing the catheter with his or her finger; (3) the
health care worker withdraws the needle by grasping the hub end
(opposite the point end) while at the same time applying pressure
to the patient's skin at the insertion site with his or her free
hand; and (4) the health care worker then tapes the now inserted
catheter to the patient's skin and connects the exposed end of the
catheter, the catheter hub, to the source of the fluid to be administered
into the patient's vein.
The problem is that immediately after the withdrawal of the needle
from the patient's vein, the health care worker who is, at this
time involved in at least two urgent procedures must place the exposed
needle tip at a nearby location and address the tasks required to
accomplish the needle withdrawal. It is at this juncture that the
exposed needle tip creates a danger of an accidental needle stick
or scratch occurring, which leaves the health care worker vulnerable
to the transmission of dangerous blood-borne pathogens, including
AIDS and hepatitis.
This danger to the health care worker from accidental needle sticks
has caused an impetus for the development of a safer IV catheter
in which the occurrence of such accidental needle sticks is prevented.
As a result, numerous different safety catheters have been developed
to achieve this result, one of which is disclosed, for example,
in Swedish Patent publication SE556318. In these safety IV catheters,
upon the withdrawal of the needle from the patient, a protective
member is automatically positioned over the exposed needle tip so
that accidental contact with the needle tip is prevented.
Among the problems that have been encountered in the use of currently
available safety IV catheters is that the protective guard that
is positioned over the needle tip after needle removal may itself
be moved away from its protective position so that the needle tip
is no longer shielded by the needle guard. This may occur, for example,
when a force is inadvertently applied to the needle guard, to overcome
the retentive force that had previously maintained the protective
guard over the needle tip. Other problems associated with the known
safety catheter is their relative complexity, high cost, and difficulty
of fabrication.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide
a safety IV catheter which reliably and automatically prevents accidental
contact with the needle tip after use.
It is a further object of the invention to provide a safety IV
catheter in which removal of the needle guard from the needle after
needle withdrawal is effectively prevented even when a force is
applied to the needle.
It is another object of the present invention to provide a safety
IV catheter of the type described which is relatively simple and
inexpensive to fabricate.
To these ends, the safety IV catheter of the invention includes
an end cap or guard and a disc-shaped lock plate having an opening
through which the needle passes. An upper end of a actuator member
passes through a second off-center opening in the lock plate and
its other, lower end passes through an opening in a flange of the
needle hub. In the prepared or ready position of the catheter, one
end of the needle guard is received within the catheter hub and
its other end is mounted about the distal end of the needle hub.
As the needle is retracted to the activated position, the tip of
the needle is received within the needle guard, and the lost motion
of the actuator member is taken up by the engagement of the needle
hub flange with the lower end of the actuator member. The axial
force now exerted by the actuator member on the lock plate causes
the latter to cant or rock about the needle shaft so that it firmly
engages and grips the needle, thereby to securely retain the needle
tip in the needle guard and prevent axial movement of the needle.
Further movement of the needle hub increases the locking force exerted
by the lock plate on the needle tip.
To the accomplishment of the above and to such further objects
as may hereinafter appear, the present invention relates to a safety
IV catheter as defined in the appended claims, and as described
in the following specification as considered with the accompanying
drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation, partly in cross-section, of a safety
IV catheter in accordance with one embodiment of the invention in
the ready position;
FIG. 2 is a side elevation, partly in cross-section, of the safety
IV catheter of FIG. 1 in the activated position;
FIG. 2A is an enlarged view of a portion of the catheter of FIGS.
1 and 2; and
FIG. 3 is a side elevation of a safety IV catheter in accordance
with a modification of the invention shown in the activated position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The safety IV catheter of the invention, generally designated 10
as in the embodiment illustrated in FIGS. 1 and 2 includes a needle
hub 12 which securely receives the proximal end of a needle 14 having
a sharpened tip 16. As is conventional, the needle 14 is received
within a hollow tubular catheter 18 the proximal end of which is
concentrically affixed within the distal end of a catheter hub 20.
The catheter hub 20 terminates at its proximal end in a luer fitting
22 adapted to receive a tubing set, which, in a known manner, administers
intravenous fluid into the patient.
In use, the distal tip of the needle 14 and the catheter 18 are
inserted into a patient's vein. Thereafter, the health care practitioner
manually places the catheter 18 further into the vein and then withdraws
the needle 14 by grasping and moving by hand the proximal end of
the needle hub 12. The luer 22 of the catheter hub 20 is then fitted
with a source of the fluid that is to be administered into the patient's
vein. In accordance with the present invention, as the needle 14
is completely withdrawn from the patient, the bare tip 16 of the
needle is automatically and securely locked within a needle guard
so that accidental contact with the needle tip is prevented.
To this end, as shown in FIG. 1 the safety IV catheter of the
invention includes a needle guard 24 the proximal end of which
is releasably seated over the frusto-conical distal end 26 of the
needle hub 12 when the catheter 18 is in the ready position shown
in FIG. 1. The distal end 28 of the needle guard 24 is split at
29 to allow the guard to fit snugly into the luer end of the catheter
hub 20 and to be readily released when the catheter hub 20 is pulled
away. A flange 30 extends about the lower proximal end of split
end 29. The needle guard includes a lower depending portion 32 that
extends downwardly from flange 30. An internal shelf 34 in portion
32 includes, as seen best in FIG. 2A, an axially offset fulcrum
or pivot point 35 formed at the junction of a tapered surface 36
and a level upper surface 37. Axially offset projection 38 is formed
at the upper end of portion 32 and a lock plate 40 is positioned
between the upper surface of shelf 34 and the lower end of projection
38.
Split end 28 flange 30 shelf 34 and lock plate 40 each include
an axially aligned opening through which the needle 14 freely passes
when the catheter is in the ready position. Lock plate 40 also includes
an off-axis opening 42 through which the upper end of an actuator
member 44 passes. In the embodiment of FIGS. 1 and 2 a bead 46
having a diameter greater than that of opening 42 is formed at the
upper end of actuator member 44 to prevent it from passing through
opening 42. The lower end of actuator member 44 passes through an
opening 48 in a flange 50 affixed to the periphery of needle hub
12. A bead 52 having a diameter greater than that of opening 48
is affixed to the lower end of actuator member 44 to prevent it
from passing through the opening. Member 44 may be, as in the embodiment
of FIG. 1 in the form of an elongated rod preferably made of a
material such as a high-density polyethylene that allows it to flex
or spring slightly.
In use, after the catheter 18 is inserted into the patient's blood
vessel, the catheter hub is held in place with a finger of one hand,
and needle hub 12 is grasped by the thumb and forefinger of the
other hand to withdraw the needle from the patient and also to separate
the needle hub 12 from the lower end of the needle guard 28. As
the needle hub 12 is retracted, relative lost motion is effected
between the needle hub 12 and the actuator member 44 until the needle
tip 16 is received within the split end 29 of the needle guard 24
as seen in FIG. 2. At about this time, also as shown in FIG. 2
the flange 50 on needle hub 12 engages the bead 52 at the lower
end of actuator member 44 thereby to take up the lost motion of
the actuator member 44. This causes the lock plate 40 to cant or
rock about fulcrum 35 and the needle shaft in a counterclockwise
direction, as viewed in FIG. 2 so that the lock plate 40 securely
grips and binds the needle shaft to prevent further axial motion
of the needle whose tip is now completely enclosed within the split
end 29 of the needle guard 24.
Continued motion of the needle hub 12 away from the catheter hub
20 releases the needle guard 24 and needle hub 20 from the catheter
hub 20. As the needle 14 is pulled further away from catheter 18
the actuator member 44 in combination with the lock plate 40 exert
a force on the needle guard 24 to pull the needle guard out of the
lower end of the catheter hub 20.
In the event an upward axial force is thereafter inadvertently
applied to the needle guard 24 the locking force exerted by the
lock plate 40 on the needle shaft, preventing movement of the needle
tip away from the needle guard 24 is increased. Moreover, if an
inadvertent downward force is thereafter applied to the needle guard
24 the internal projection 38 is moved into engagement with the
lock plate 40 so as to exert a downward force on the lock plate
40 that maintains it in its canted or locking position on the needle
shaft.
The embodiment of the invention illustrated in FIG. 3 is the same
as that illustrated in FIGS. 1 and 2 except that the actuator member
44a is in the form of a thin wire having a knot 54 at its upper
end, which passes through an opening 42 in lock plate 40. Knot 50
secures the upper end of the wire actuator member to the lock plate
40 and prevents the upper end of the wire actuator member from
passing downward through the opening in the lock plate 40.
It will be appreciated that the safety IV catheter of the invention
provides reliable protection against inadvertent contact with a
needle tip after catheter insertion, even when an axial force is
subsequently applied to the needle guard. It will also be understood
that the safety catheter of the invention may be fabricated easily
and at a relatively low cost by the use of current fabricating processes.
It will be additionally understood that whereas the present invention
has been described hereinabove with respect to several preferred
embodiments, modifications to those embodiments may be made, such
as the use of a fish line or other strong but flexible material
as the actuator member, without necessarily departing from the spirit
and scope of the invention. |