Note: Descriptions are shown in the official language in which they were submitted.
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INTRAVENOUS CATHETER INTRODUCING DEVICE
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an intravenous catheter
introducing device, more particularly to an intravenous
catheter introducing device with a needle cannula which is
retractable into a tubular plunger for safe disposal.
2. Description of the Related Art
Intravenous catheter introducing devices are generally
used to administer a medication fluid into or to draw blood
from a patient's vein. Referring to Fig. 1, a conventional
intravenous catheter introducing device 9 is shown to include
a tubular needle seat 91 with a hub end 911, a needle cannula
94 secured to the hub end 911, a catheter hub 92 sleeved
on the needle seat 91, and a flexible tubular catheter 93
secured to the catheter hub 92. In use, the catheter 93 and
the needle cannula 94 are inserted into the patient's vein
by a health care worker by piercing the patient's vein with
a sharp tip of the needle cannula 94 which projects outwardly
of the catheter 93. The health care worker then withdraws
the needle cannula 94 from the catheter 93 with one hand
and, at the same time, applies pressure to the patient's
skin with the other hand, thereby leaving the catheter 93
in the patient's vein. Subsequently, a transfusion member
(not shown) with the medication fluid or an empty barrel
is connected to the catheter hub 92 for administering the
medication f luid into the patient' s vein or for drawing blood.
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At this time, the exposed sharp tip of the used needle cannula
94 may create a danger of an accidental needle stick.
Moreover, the conventional intravenous catheter
introducing device 9 is specifically not suitable for
patients whose blood pressure is not sufficient to permit
flow of blood therethrough, such as an emergency case, aged
people, and pediatrics patients, and patients whose target
vein is barely visible due to abundant adipose tissue, such
as women and obese patients, since the health care worker
will have difficulty determining whether the catheter 93
has been successfully introduced into the target vein, and
may need to locate the vein by moving the needle cannula
94 in the skin of the patient, thereby complicating and
prolonging the cannulation procedure and causing great
discomfort to the patient.
Furthermore, although conventional self-retracting IV
catheter introducers permit self-retraction of the used
needle cannula into the syringe barrel after introduction
of the catheter is completed, the blood in the barrel may
be forced out of the barrel during the retraction of the
used needle cannula so that blood contamination may occur.
SUMMARY OF THE INVENTION
One object of the present invention is to provide an
intravenous catheter introducing device which can be
operated easily and safely to retract a used needle cannula
with one hand, and which can prevent the blood from being
forced out thereof.
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Another object of the present invention is to provide
an intravenous catheter introducing device which can
facilitate flowing of the blood into the needle cannula to
thereby enable the operator to conveniently observe and check
the introduction of a catheter.
According to this invention, the intravenous catheter
introducing device includes:
a needle cannula which has a front segment terminating
at a tip end, and a rear connecting end opposite to the front
segment along the axis in a longitudinal direction;
a tubular needle seat which includes a front hub portion
that extends along the axis to terminate at a front end,
and that is disposed to fix the rear connecting end therein,
a gripped portion that extends from the front hub portion
away from the front end, and a rear plug portion that extends
from the gripped portion and distal from the front hub portion,
and that has an internal duct extending through the gripped
portion to be communicated with the rear connecting end;
a barrel which has an inner surrounding barrel surface
defining a passage therein, the passage having rearward and
forward openings, the inner surrounding barrel surface
including a larger-diameter portion and a smaller-diameter
portion which are disposed proximate to the rearward and
forward openings, respectively, the larger-diameter portion
having a retaining area which is spaced apart from the
smaller-diameter portion in the longitudinal direction;
a tubular grip member which, in a position of use, is
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disposed to hold, with a holding force, the gripped portion
in a position of immovability along the axis relative to
the retaining area;
a tubular plunger which is disposed to be movable in the
passage along the larger-diameter portion, the plunger
having a front opened end wall which is movable to abut against
the grip member so as to place the tubular plunger in a
pre-disposal position, a rear end wall which is disposed
opposite to the front opened end wall, and which extends
outwardly of the rearward opening so as to be manually
operable, and an intermediate surrounding wall which is
interposed between the front opened end wall and the rear
end wall, and which defines an accommodation compartment;
a tubular receptacle which has a socket end, an
air-permeable end, and a tubular wall segment interposed
therebetween to confine a flashback chamber, wherein when
the tubular grip member is in the position of use, the tubular
receptacle is retained in the accommodation compartment by
a first friction force, with the socket end and the
air-permeable end respectively confronting the rear plug
portion and the rear end wall to establish air communication
between the internal duct and the flashback chamber, such
that when the tubular plunger is in the pre-disposal position,
the socket end is engaged with the rear plug portion, such
that when the grip member is pushed forward by virtue of
a forward movement of the front opened end wall against the
holding force, the gripped portion is released from the grip
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member so as to permit axial movement of the gripped portion
relative to the retaining area, and such that when the gripped
portion is released from the grip member, a continued forward
movement of the front opened end wall against the first
5 friction force will result in movement of the tubular needle
seat together with the tubular receptacle, through the
engagement of the rear plug portion with the socket end,
towards the rear end wall by virtue of a biasing force so
as to place the tubular needle seat and the needle cannula
in a disposal position, where the tip end of the needle cannula
is retracted into the passage, and where the socket end is
closer to the rear end wall than in the position of use;
a biasing member disposed to provide the biasing force;
a catheter hub which defines therein a duct that permits
extension of the front segment of the needle cannula
therethrough; and
a tubular catheter having a proximate segment which is
inserted into the duct, and a distal segment which extends
from the proximate segment and which surrounds and sheathes
the front segment of the needle cannula while permitting
the tip end to project forwardly of the distal segment for
piercing a patient's skin.
Preferably, an air-permeable member which is made from
aporousmaterial is integrally formed with the air-permeable
end so as to prevent blood from trickling out of the flashback
chamber.
Preferably, the tubular plunger has an outlet which
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permits air communication between the accommodation
compartment and the ambient air, and which is disposed
downstream of the air permeable end.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the present invention
will become apparent in the following detailed description
of the preferred embodiments of the invention, with reference
to the accompanying drawings, in which:
Fig. l is a perspective view of a conventional IV catheter
introducing device;
Fig. 2 is an exploded sectional view of a first preferred
embodiment of an intravenous catheter introducing device
according to this invention;
Fig. 3 is a sectional view of the first preferred
embodiment in a ready-to-use position;
Fig. 4 is a fragmentary sectional view of a portion of
the first preferred embodiment;
Fig. 5 is a sectional view of the first preferred
embodiment in a position of use;
Fig. 6 is a sectional view of the first preferred
embodiment in a pre-disposal position;
Fig. 7 is a sectional view of the first preferred
embodiment during an operation of retracting a needle
cannula;
Fig. 8 is a sectional view of the first preferred
embodiment in a retracted position;
Fig. 9 is a sectional view of the first preferred
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embodiment showing two outlets in a closed position;
Fig. 10 is a sectional view of the second preferred
embodiment of an intravenous catheter introducing device
according to this invention;
Fig. 11 is a sectional view of the second preferred
embodiment in a retracted position;
Fig. 12 is a sectional view of the third preferred
embodiment of an intravenous catheter introducing device
according to this invention;
Fig. 13 is a sectional view of the third preferred
embodiment in a retracted position; and
Figs. 14 to 18 respectively are sectional view of the
fourth to eighth preferred embodiments of an intravenous
catheter introducing device according to this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Before the present invention is described in greater
detail, it should be noted that same reference numerals have
been used to denote like elements throughout the
specification.
Referring to Figs. 2 to 4, the first preferred embodiment
of an intravenous catheter introducing device according to
the present invention is shown to comprise a barrel 1, a
needle cannula 23, a tubular needle seat 22, a tubular grip
member 21, a tubular plunger 3, a tubular receptacle 34,
a biasing member 4, a catheter hub 24, a tubular catheter
25, and a tip protector 26.
The barrel 1 has a surrounding wall 13 surrounding an
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axis. The surrounding wall 13 has an inner surrounding barrel
surface 130 which defines a passage 11 therein. The passage
11 has rearward and forward openings 131,132 which are
opposite to each other in a longitudinal direction along
the axis. The inner surrounding barrel surface 130 includes
a larger-diameter portion 133 and a smaller-diameter portion
134 which are disposed proximate to the rearward and forward
openings 131,132, respectively, and a shoulder 135 which
is interposed therebetween. The larger-diameter portion 133
has a projecting retaining area 137 which is spaced apart
from the smaller-diameter portion 134 in the longitudinal
direction. The smaller-diameter portion 134 includes an
entry region 15, a transit region 17 which extends from the
entry region 15 forwardly, and an inner annular abutment
surface 16 which confronts rearwardly. The barrel 1 further
has a finger flange 138 disposed proximate to the rearward
opening 131.
The needle cannula 23 has a front segment 231 terminating
at a tip end 232, and a rear connecting end 233 opposite
to the front segment 231 along the axis.
The tubular needle seat 22 includes a front hub portion
220 which extends along the axis to terminate at a front
end 225 to be surrounded by the entry region 15, and which
is disposed to fix the rear connecting end 233 of the needle
cannula 23 therein, a gripped portion 222 which extends from
the front hub portion 220 away from the front end 225, and
a rear plug portion 223 which extends from the gripped portion
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222 and distal from the front hub portion 220 and which has
an internal duct 224 extending through the gripped portion
222 along the axis to be communicated with the rear connecting
end 233 of the needle cannula 23. The front hub portion 220
has a shoulder surface 221 which is disposed rearwardly of
the front end 225, and which is spaced apart from the inner
annular abutment surface 16 by the transit region 17.
The tubular grip member 21 is retained at the retaining
area 137 of the barrel 1 in a position of use so as to hold
the gripped portion 222 of the needle seat 22 in a position
of immovability along the axis relative to the retaining
area 137 by virtue of a holding force. To be specific, the
tubular grip member 21 is disposed in retaining engagement
with the projecting retaining area 137 of the larger-diameter
portion 133, and in gripping engagement with the gripped
portion 222 of the needle seat 22 by second and third friction
forces, respectively, which cooperate in radial directions
to serve as the holding force.
The tubular plunger 3 is disposed to be movable in the
passage 11 along the larger-diameter portion 130. The plunger
3 has a front opened end wall 321, a rear end wall 322 which
is opposite to the front opened end wall 321 and which extends
outwardly of the rearward opening 131 so as to be manually
operable, and an intermediate surrounding wall 32 which is
interposed between the front opened end wall 321 and the
rear end wall 322 and which defines an accommodation
compartment 31. The intermediate surrounding wall 32 has
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a plurality of ribs 324 which are formed on an outer surface
thereof and adjacent to the rear end wall 322.
The tubular plunger 3 has two outlets 33 which communicate
the accommodation compartment 31 with the ambient air, and
5 which are disposed downstream of the air permeable end 344.
In this embodiment, the outlets 33 are formed in the
intermediate surrounding wall 32 adjacent to the rear end
wall 322 to facilitate closing by a user's finger when the
user grips and moves the tubular plunger 3.
10 The tubular plunger 3 further has a deformable sealing
member 36 which is configured to surround the front opened
end wall 321, and which is in air-tight sliding engagement
with the larger-diameter portion 130.
The tubular receptacle 34 has a socket end 343 and an
air-permeable end 344 spaced apart from each other in the
longitudinal direction, and a tubular wall segment 340
interposed therebetween to confine a flashback chamber 342.
In the position of use, the tubular receptacle 34 is retained
in the accommodation compartment 31 by a first friction force
generated between protrusion and recess portions 341,323
such that the socket end 343 and the air-permeable end 344
respectively confront the rear plug portion 223 and the rear
end wall 322 to establish an air communication between the
internal duct 224 and the flashback chamber 342. An
air-permeable member 35 is integrally formed with the
air-permeable end 344, and is made from a porous material.
The rear end wall 322 of the tubular plunger 3 defines
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an access opening for insertion of the tubular receptacle
34 into the accommodation compartment 31 therethrough. An
end cap 37 is detachably mounted to the rear end wall 322
to close the access opening.
The barrel 1 has a forward end wall 139 which defines
the forward opening 132. The biasing member 4 is in the form
of a coil spring 4 which surrounds the front segment 231
of the needle cannula 23, and which is compressed between
the forward end wall 139 and the shoulder surface 221 of
the needle seat 22 to provide a biasing force to move the
needle seat 22 rearwardly.
The catheter hub 24 is detachably sleeved on the
surrounding wall 13 of the barrel 1, and defines therein
a duct 241 that permits extension of the front segment 231
of the needle cannula 23 therethrough.
The tubular catheter 25 has a proximate segment 251 which
is inserted into the duct 241, and a distal segment 252 which
extends from the proximate segment 251 and which surrounds
and sheathes the front segment 231 of the needle cannula
23 while permitting the tip end 232 to project forwardly
of the distal segment 252 for piercing a patient's skin.
The tip protector 26 is removably sleeved on the
surrounding wall 13 for shielding the needle cannula 23.
In the position of use, the front hub portion 220 of the
needle seat 22 is retained at the retaining area 137 by the
holding force (i.e., the second and third friction forces),
and the inner annular abutment surface 16 is spaced apart
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from the shoulder surface 221 by the transit region 17.
Referring to Figs. 3, 4 and 5, in an IV introducing stroke,
the tip protector 26 is removed first to expose the tip end
232 of the needle cannula 23. The operator grips the
surrounding wall 13 of the barrel 1 and pierces the patient' s
vein with the tip end 232 so as to introduce the tubular
catheter 25 into the vein. The blood flowing into the passage
11 is visible from the surrounding wall 13 so that the operator
can check whether the needle cannula 23 has been inserted
properly into the vein. The operator can then separate the
catheter hub 24 from the barrel 1, and the IV introducing
operation is completed.
Referring to Figs. 5 and 6, since the passage 11 is in
air communication with the accommodation compartment 31 via
the flashback chamber 342 so as to be communicated with the
ambient air through the outlets 33, after the IV introducing
stroke, the operator can press the tubular plunger 4 forwardly
so as to move the deformable sealing member 36 to abut against
the grip member 21 to thereby place the tubular plunger 3
in a pre-disposal position. At this time, the blood in the
passage 11 can flow into the flashback chamber 342 due to
air communication of the passage 11 with the ambient air,
and the air-permeable member 35 can prevent the blood from
trickling out of the flashback chamber 342. Thus, the blood
will not be forcedout of the barrel 1 during forward pressing
of the tubular plunger 3.
Subsequently, the socket end 343 is engaged with the rear
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plug portion 223. When the grip member 21 is pushed forward
by virtue of a forward movement of the tubular plunger 3
against the holding force, the grip member 21 is moved to
disengage from the retaining region 137 so that the second
friction force disappears, and the shoulder surface 221 of
the needle seat 22 is moved to pass from the entry region
to the transit region 17 to abut against the inner annular
abutment surface 16. Then, by virtue of the abutment of the
shoulder surface 221 against the inner annular abutment
10 surface 16, the gripped portion 222 is released from the
grip member 21 so that the third friction force disappears.
The time lag between the releasing of the second and third
friction forces can result in a smooth operation of the
tubular plunger 3. At the same time, by virtue of a
15 counteracting effect of the forward end wall 139 of the barrel
1 and the coil spring 4, the protrusion portion 341 of the
receptacle 34 is moved to disengage from the recess portion
323 in the plunger 3 so as to permit releasing of the coil
spring 4.
Therefore, as shown in Fig. 7, through the engagement
of the rear plug portion 223 with the socket end 343, arearward
movement of the needle seat 22 will, by virtue of the biasing
force of the coil spring 4, force the tubular receptacle
34 to move towards the rear end wall 322 to place the tubular
needle seat 22 and the needle cannula 23 in a disposal position,
as shown in Fig. 8, where the tip end 232 of the needle cannula
23 is retracted into the passage 11, and where the socket
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end 343 is closer to the rear end wall 322 than in the position
of use.
It is noted that when the tubular plunger 3 is pressed
to place the tubular needle seat 22 and the needle cannula
23 in the disposal position, the tubular plunger 3 is retained
at the larger-diameter portion 133 through snug engagement
between an annular recess 136 and an annular projection 325
so as to prevent rearward pulling of the tubular plunger
3 for reuse. Moreover, the forward pressing of the tubular
plunger 3 can be limited by the ribs 324 that abut against
the barrel 1 at the rearward opening 131 so as to prevent
excess forward movement of the tubular plunger 3, which may
cause the grip member 21 to deform and interfere with the
rearward movement of the needle seat 22.
Referring to Fig. 9, during the IV introducing operation,
if blood is not observed in the passage 11, the operator
can hold the tubular plunger 3 and close the outlets 33 with
his/her thumb and index f inger to interrupt air communication
between the passage 11 and the ambient air. Then the operation
can pull the tubular plunger 3 rearwardly so as to generate
a reduced pressure in the passage 11 to thereby facilitate
flow of blood into the passage 11. Thus, the operator can
easily check whether the tubular catheter 25 has been
successfully introduced into a target vein of the patient.
Referring to Figs. 10 and 11, the second preferred
embodiment of an intravenous catheter introducing device
according to this invention is shown to be similar to the
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first preferred embodiment in construction. The difference
resides in that the tubular wall segment 340 of the tubular
receptacle 34 has an outer annular abutment surface 345
adjacent to the air-permeable end 344. The biasing member
5 4 is in the form of a coil spring 4 which surrounds the tubular
wall segment 340 and which is compressed between the front
opened end wall 321 and the outer annular abutment surface
345. Moreover, the outer annular abutment surface 345 is
retained at the recess portion 323 of the tubular plunger
10 3 to generate the first friction force.
Referring to Figs. 12 and 13, the third preferred
embodiment of an intravenous catheter introducing device
according to this invention is shown to be similar to the
first preferred embodiment in construction. The difference
15 resides in that the biasing member 4 is in the form of a
coil spring 4 which is received in the accommodation
compartment 31 of the tubular plunger 3 and which has a secured
end 43 that is secured to the intermediate surrounding wall
32 adjacent to the rear end wall 322, and a tensed end 44
that is secured to the tubular wall segment 340 of the tubular
receptacle 34 so as to remain tensed in the position of use.
Referring to Fig. 14, the fourth preferred embodiment
of an intravenous catheter introducing device according to
this invention is shown to be similar to the third preferred
embodiment in construction. The difference resides in that
the biasing member 4 has a secured end 43 which is secured
to the end cap 37.
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Referring to Fig. 15, the fifth preferred embodiment of
an intravenous catheter introducing device according to this
invention is shown to be similar to the third preferred
embodiment in construction. The difference resides in that
the outlet 33 is formed in the end cap 37 to facilitate closing
of the outlet 33 by the operator.
Referring to Fig. 16, the sixth preferred embodiment of
an intravenous catheter introducing device according to this
invention is shown to be similar to the second preferred
embodiment in construction. The difference resides in that
the outlet 33 is formed in the end cap 37, and a cover plate
38 is disposed on the tubular plunger 3, and is movable
relative to the tubular plunger 3 between closing and opening
positions, where the cover plate 38 engages with and
disengages from the end cap 37 to close and open the outlet
33, respectively.
Referring to Fig. 17, the seventh preferred embodiment
of an intravenous catheter introducing device according to
this invention is shown to be similar to the second preferred
embodiment in construction. The difference resides in that
the outlet 33 is formed in the rear end wall 322 of the tubular
plunger 3, and the intermediate surrounding wall 32 of the
tubular plunger 3 has an annular barrier 327 formed adjacent
to the rear end wall 322 such that the air-permeable end
344 of the tubular receptacle 34 is stopped by the annular
barrier 327 when the tubular receptacle 34 is moved to the
disposal position.
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Referring to Fig. 18, the eighth preferred embodiment
of an intravenous catheter introducing device according to
this invention is shown to be similar to the first preferred
embodiment in construction. The difference resides in that
the outlet 33 is formed in the rear end wall 322 of the tubular
plunger 3, and the intermediate surrounding wall 32 of the
tubular plunger 3 has an annular barrier 327 formed adjacent
to the rear end wall 322 such that the air-permeable end
344 of the tubular receptacle 34 is stopped by the annular
barrier 327 when the tubular receptacle 34 is moved to the
disposal position. In addition, a cover plate 38 is disposed
on the tubular plunger 3 and is movable relative to the tubular
plunger 3 between closing and opening positions, where the
cover plate 38 engages and disengages from the rear end wall
322 to close and open the outlet 33, respectively.
As illustrated, according to the intravenous catheter
introducing device of this invention, the used needle cannula
23 can be retracted into the passage 11 of the barrel 1 to
thereby avoid occurrence of an accidental needle stick.
Further, during the forward pressing of the tubular plunger
3 to retract the needle cannula 23, since the passage 11
is air communicated with the ambient air, the blood in the
passage 11 may flow into the flashback chamber 342, and the
air-permeable member 35 can prevent the blood from trickling
out of the flashback chamber 342. Thus, the blood will not
be forced out of the barrel 1. Moreover, during the IV
introducing operation, once blood is not observed in the
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passage 11, the operator can close the outlet (s) 33 and pull
the tubular plunger 3 rearwardly to generate a reduced
pressure in the passage 11 to thereby facilitate flow of
blood into the passage 11. Thus, the operator can easily
check whether the tubular catheter 25 has been successfully
introduced into a target vein of the patient.
While the present invention has been described in
connection with what are considered the most practical and
preferred embodiments, it is understood that this invention
is not limited to the disclosed embodiments but is intended
to cover various arrangements included within the spirit
and scope of the broadest interpretations and equivalent
arrangements.
