United States Patent (19)
`Wozencroft
`
`54 CATHETER PLACEMENT UNITS
`75
`Inventor: Robert Michael Wozencroft, Surbiton,
`England
`73) Assignee: Sterimatic Holdings Limited, Tortola,
`Virgin Islands (Br)
`
`56)
`
`(21) Appl. No.: 516,829
`22 Filed:
`Aug. 18, 1995
`(30)
`Foreign Application Priority Data
`Aug. 24, 1994 GB United Kingdom ................... 9417073
`(51
`Int. Cl. .............. A61M S/178
`52 U.S. Cl. ......................................... 604/164; 604/165
`58) Field of Search .................................. 604/164, 110,
`604/263, 198, 162, 166, 168, 165
`References Cited
`U.S. PATENT DOCUMENTS
`4,778,453 10/1988 Lopez.
`4,790,828 12/1988 Dombrowski et al. .
`4,944,725 7/1990 McDonald.
`4,944,728 7/1990 Carrell et al..
`4,950,252 8/990 Luther et al. .
`4,978,344 12/1990 Dombrowski et al..
`4,994,042 2/1991 Vadher.
`5,007,901
`4/1991 Shields ...............
`5,013,304 5/1991 Russell et al. ..
`5,026,351
`6/1991 Dizon.
`5,051,109 9/1991 Simon.
`5,102,394 4/1992 Lasaitis et al. ......................... 604/164
`5,176,655
`1/1993 McCormicket al..
`5,183,468 2/1993 McLees.
`5,186,712 2/1993 Kelso et al. ............................ 604/164
`5,215,528 6/1993 Purdy et al. ............................ 604164
`5,279.591
`1/1994 Simon.
`5,300,045 4/1994 Plassche, Jr. .
`5,348,544 9/1994 Sweeney et al. .
`5,533,974 7/1996 Gaba ....................................... 604/164
`
`--- 604/164
`... 604/164
`
`
`
`US005718688A
`Patent Number:
`11
`45 Date of Patent:
`
`5,718,688
`Feb. 17, 1998
`
`5,584,809 12/1996 Gaba ....................................... 604f110
`5,599,310 2/1997 Bogert ..................................... 604/164
`
`FOREIGN PATENT DOCUMENTS
`WO 89/10767 11/1989 WIPO.
`WO 90/08564 8/1990 WIPO :
`WO 91/01151
`2/1991 WIPO.
`WO 93/05840 4/1993 WIPO.
`
`Primary Examiner-Mark Polutta
`Attorney, Agent, or Firm-Young & Thompson
`57
`ABSTRACT
`A catheter placement unit comprises a catheter having an
`axial bore, a catheter hub at one end of the catheter, an
`introducing needle having a pointed tip for introducing the
`catheter into a desired position in a patient's body, and a
`needle hub on the needle remote from the tip for mounting
`the needle so that it extends through the catheter bore for
`introduction of the catheter into the patient's body and so
`that it can subsequently be withdrawn from the catheterbore
`leaving the catheter in position in the patient's body. The
`unit includes a needle tip protector on the needle for shield
`ing the needle tip when the needle has been withdrawn from
`the catheterbore. The needle tip protector includes a locking
`device which is initially in an unlocked position permitting
`withdrawal of the needle from the catheter bore but which is
`arranged to be placed in a locked position, in which the
`locking device engages the outer surface of the needle, by
`withdrawal of the needle from the catheterbore so as to lock
`the needle tip protector on the needle in the shielding
`position. The locking device retains the catheter hub on the
`needle when the locking device is in the unlocked position
`and releases the catheter hub from the needle when the
`locking device is in the locked position. Separation of the
`catheter from the needle is therefore prevented until the
`needle has been withdrawn from the catheterbore to trigger
`shielding of the needle tip.
`
`9 Claims, 2 Drawing Sheets
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`1
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`B. Braun 2011
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`U.S. Patent
`US. Patent
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`Feb. 17, 1998
`Feb. 17, 1998
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`5,718,688
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`US. Patent
`U.S. Patent
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`Feb. 17, 1998
`Feb. 17, 1998
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`Sheet 2 of 2
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`1.
`CATHETER PLACEMENT UNITS
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`catheter from the unit in such a manner as to expose the
`contaminated needle tip after the catheter has been placed in
`position in the patient's body but prior to withdrawal of the
`needle in the required manner to trigger the shielding action.
`Furthermore, because the provision of the locking device
`renders a retaining strap extending between the needle tip
`protector and the needle hub unnecessary, the same needle
`tip protector may be used with needles of different lengths,
`and there is no need for different arrangements to be
`produced for different needle lengths. The unit may also be
`produced and assembled relatively easily.
`BRIEF DESCRIPTION OF THE DRAWINGS
`In order that the invention may be more fully understood,
`embodiments of catheter placement unit in accordance with
`the invention will now be described, by way of example,
`with reference to the accompanying drawings in which:
`FIGS. 1 and 2 are broken away top views of a first
`embodiment in its unlocked and locked positions respec
`tively;
`FIG. 3 is a top view of a variant of the first embodiment;
`FIGS. 4 and 5 are broken away top views of a second
`embodiment in its unlocked and locked positions respec
`tively;
`FIGS. 6 and 7 are broken away top views of a third
`embodiment in its unlocked and locked positions respec
`tively; and
`FIG. 7A is a rear view of part of the third embodiment
`taken in the direction of the arrow Ain FIG. 7.
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`BACKGROUND OF THE INVENTION
`It is established medical practice to introduce a flexible
`tubular catheter into a desired position in a patient's body by
`means of a catheter placement unit which includes an
`introducing needle extending externally or internally of the
`catheter and projecting beyond the end of the catheter. In use
`of such a catheter placement unit to place a catheter within
`a patient's vein, for supply of infusion fluid for example, the
`needle tip projecting beyond the end of the catheter serves
`to puncture the patient's skin and to locate the catheter
`within the vein. When the catheter is suitably positioned, as
`may be determined by the flow of blood in the hub of the
`needle, the needle may be withdrawn leaving the catheter in
`position in the vein. However the need to withdraw the
`needle from the catheter leads to a risk that doctors or nurses
`will accidentally stick themselves with the needle, and this
`can be highly dangerous due to the risk of transfer of
`blood-related diseases.
`WO 93/05840 discloses a catheter placement unit incor
`porating a needle tip protector which is mounted on the
`needle so that, on withdrawal of the needle from the catheter,
`the needle tip protector is caused to assume a shielding
`position in which it shields the needle tip, retention of the
`needle tip protector on the needle being ensured by a strap
`extending between the protector and the needle hub. How
`ever the provision of such a strap complicates production
`and assembly of the unit, as well as being inconvenient in
`use and limiting the needle tip protector to use with a needle
`of a length appropriate to the length of the strap.
`WO 90/08564 discloses a needle tip protector which is
`retained in a position on the needle shielding the needle tip
`withoutrequiring the provision of a strap extending between
`the protector and the needle hub. To this end the needle tip
`protector includes a locking device which is initially in an
`unlocked position permitting withdrawal of the needle from
`the catheter but which is arranged to be placed in a locked
`position by withdrawal of the needle from the catheter so as
`to lock the needle tip protector on the needle in its shielding
`position. However such a needle tip protector is complicated
`to produce and assemble, as well as suffering from the
`serious disadvantage that, since no special provision is made
`for release of the needle tip protector from the catheter hub
`45
`on withdrawal of the needle, there is a danger that the
`catheter may be accidentally pulled off the needle leaving
`the needle tip unprotected or that the catheter may be
`accidentally withdrawn from the patient's vein during with
`drawal of the needle.
`Other catheter placement units incorporating needle tip
`protectors are disclosed in U.S. Pat. No. 4,978,344, U.S. Pat.
`No. 5,051,109, and U.S. Pat. No. 5,176,655, but all of these
`suffer from one or more of the disadvantages referred to
`above.
`It is an object of the invention to provide a catheter
`placement unit with a needle tip protector which reliably
`prevents needle stick injuries on withdrawal of the needle
`without requiting the provision of a strap acting between the
`needle hub and the needle tip protector.
`SUMMARY OF THE INVENTION
`According to the present invention there is provided a
`catheter placement unit as defined in the accompanying
`claims.
`The claimed arrangement is advantageous in that it
`ensures that there can be no accidental separation of the
`
`DETALED DESCRIPTION OF THE DRAWINGS
`The catheter placement unit 1 shown in FIG.1 comprises
`an introducing needle 2 mounted on a transparent plastics
`needle hub 3 in conventional manner, and a flexible tubular
`catheter 4 mounted on a plastics catheter hub 5 in conven
`tional manner. The needle 2 extends within the catheterbore
`so that its pointed tip projects from the end of the catheter
`4. An annular flange 6 is provided on the end of the catheter
`hub 5.
`In addition the catheter placement unit 1 includes a needle
`tip protector 8 mounted on the needle 2 between the needle
`hub 3 and the catheter hub 5. The needle tip protector 8
`includes a locking device 9 comprising two co-operating
`locking parts 10 and 11 which are pivotally interconnected
`by a pivot post 12 on the part 10 which is a snap fit within
`a pivot tube 13 on the part 11. It should be appreciated that
`a top wall of the locking part 11 is shown removed in the
`FIG. in order to render the interior of the locking device 9
`visible, although the opposite wall 14 of the locking part 10
`can readily be seen.
`The locking part 10 has an end wall 15 provided with a
`slot 16 through which the needle 2 extends, and the locking
`part I1 has an opposite end wall 17 provided with a slot 18
`through which the needle 2 also extends in the initial
`position shown in FIG. 1. The locking part 11 additionally
`has two side walls 19 and 20. A locking cam21 is connected
`to the side wall 19 of the part 11 by a flexible hinge portion
`22 so as to permit limited pivotal movement of the locking
`cam 21 relative to the remainder of the part 11.
`The locking parts 10 and 11 also have respective retaining
`jaws 23 and 24 for retaining the catheter hub 5therebetween.
`When the locking device 9 is in the unlocked position,
`shown in FIG. 1, in which the device is placed during
`assembly with the needle 2 extending through the slots 16
`and 18 in the locking parts 10 and 11, the jaws 23 and 24
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`firmly engage the catheter hub 5 so as to prevent the catheter
`4 being removed from the unit in such a manner as to leave
`the needle tip exposed after it has been introduced into the
`patient's body. It will be appreciated that the jaws 23 and 24
`are held in this closed position by virtue of engagement of
`the needle 2 within the two slots 16 and 18. Furthermore, in
`this unlocked position, the needle 2 holds a tongue 25 on the
`part 10 in a depressed position in which it compresses a leaf
`spring 26 located between the tongue 25 and the adjacent
`side wall 20 of the part 11. In this unlocked position the
`locking cam21 is clear of the needle 2 so that the needle may
`slide in relation to locking device 9 as it is withdrawn from
`the catheter 4.
`In use of the unit to place a catheter in a patient's body,
`a protective sheath 27 (see FIG. 3) is first removed from the
`unit, and the tip of the needle 2 is then caused to puncture
`the patient's skin. The needle hub 3 is then manipulated to
`place the needle tip in the required position as indicated by
`the presence of blood in the needle hub 3. When the correct
`position is reached, the catheter 4 is threaded along the
`20
`needle by applying pressure with one finger to the ribbed
`outer surface 28 (see FIG. 3) of the locking part 11. The
`needle 2 is then slowly withdrawn from the catheterbore by
`gasping the needle hub 3 with one hand whilst holding the
`catheter hub with the other hand. When the needle hub 3 has
`been moved to a sufficient extent to withdraw the needle tip
`from both the catheter hub. 5 and the slot 18 in the locking
`part 11, the resilient action of the leaf spring 26 causes
`pivoting of the locking parts 10 and 11 to the locking
`position shown in FIG. 2, thus releasing the catheter hub 5
`by movement apart of the jaws 23 and 24 and permitting
`separation of the unit from the catheter 4 which remains
`attached to the patient.
`The resilient action of the leaf spring 26 also causes
`movement of the tongue 25 on the locking part 10 relative
`to the locking part 11 so as to cause the end of the tongue 25
`to override a retaining rib 29 on the end wall 17 of the
`locking part 11 with the result that the tongue 25 is retained
`by the rib 29 in a raised position in which it forces the needle
`2 into contact with the locking cam 21. The form of the
`locking cam 21 is such that further withdrawal of the needle
`2 from the locking device 9 will cause the locking cam 21
`to be pivoted in a clockwise direction as shown by the arrow
`30 in FIG.2 so as to provide increased gripping of the needle
`2 by the locking cam21, with the result that the locking cam
`45
`21 provides considerable resistance to withdrawal of the
`needle 2 from the needle tip protector 8.
`Thus the needle tip protector 8 is locked on the end of the
`needle 2 in such a manner as to safely and reliably shield the
`needle tip, and the needle 2 may be safely disposed of with
`the attached protector 8. Since the action of withdrawing the
`needle tip into the protector 8 simultaneously releases the
`catheter 4 from the unit, there is no danger of the catheter
`being accidentally withdrawn from the patient along with
`the needle or of the protector being pulled off the end of the
`needle by the catheter.
`FIG. 3 shows a variant 1' of the embodiment described in
`which the only difference is in the form of the needle hub 3
`which is provided with integral side walls 31 and 32 which
`overlap the corresponding side walls of the locking parts 10
`and 11 of the needle tip protector 8 and are provided with
`external gripping surfaces 33 and 34 The gripping surfaces
`33 and 34 may be grasped in the vicinity of the needle tip
`protector 8 between the thumb and finger of the hand in
`order to hold the needle hub 3 and the needle tip protector
`8 together as the needle tip is introduced into the patient's
`body. The user may then thread the catheter along the needle
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`into the patient's vein by applying a pushing force to the
`fibbed surface 28 of the needle tip protector 8 with one
`finger. However the fact that the side walls 31 and 32 overlap
`the corresponding side walls of the needle tip protector 8
`will discourage the user from grasping the needle tip pro
`tector 8 during withdrawal of the needle from the catheter
`bore which might otherwise have the effect of separating the
`needle tip protector 8 from the needle and exposing the
`contaminated needle tip.
`FIGS. 4 and 5 show a catheter placement unit 40 in
`accordance with a second embodiment of the invention, like
`parts being denoted by the same reference numerals as in
`FIGS. 1 and 2 and the unit 40 being shown respectively in
`the unlocked and locked positions in FIGS. 4 and 5. In this
`case the needle tip protector 41 includes a locking device
`having two locking parts 42 and 43 interconnected by a link
`44 provided with a slot 45 through which the needle 2
`extends, each of the locking parts 42 and 43 being capable
`of limited pivotal movement relative to the link44. Each of
`the locking parts 42 and 43 is also provided with an integral
`wall 46 or 47 provided with a slot 48 or 49 through which
`the needle 2 extends in the unlocked position.
`When the needle 2 is withdrawn from the catheter hub 5
`and from the slot 49 in the wall 47, this permits retaining
`jaws 50 and 51 to be sprung apart by a leaf spring 52 in order
`to release the catheter hub 5, and at the same time results in
`locking earns 53 and 54 on the locking parts 42 and 43 being
`brought into forcible engagement with the needle 2 so as to
`grip the needle 2 therebetween. Such gripping action will
`tend to be increased by any force applied to the needle 2 in
`a direction so as to tend to further withdraw the needle.
`FIGS. 6 and 7 show a catheter placement unit 60 in
`accordance with a third embodiment of the invention in the
`unlocked and locked positions respectively, like parts being
`denoted by the same reference numerals as in FIG.1 and 2.
`In this case the needle tip protector 61 comprises a locking
`device 62 having a locking part 63 which is slidably attached
`to the needle 2 and a locking part 64 which is pivotally
`mounted on the locking part 63 by virtue of an integral cam
`65 located between the needle 2 and a curved wall 66 on the
`locking part 63. In the unlocked position shown in FIG. 6,
`the locking part 64 is cocked against the action of a torsion
`spring 67 so that the catheter hub 5 is held in position on the
`needle 2 by engagement of the catheter hub 5 by the tip 69
`of the locking part 64. In this position the cam 65 permits
`sliding of the needle 2 relative to the locking device 62.
`On withdrawal of the needle from the catheter hub 5, the
`catheter hub 5 is permitted to fall away from the needle tip
`protector 61 and the locking part 64 is pivoted by the action
`of the torsion spring 67 into the position shown in FIG. 7 in
`which it shields the needle tip. Furthermore, because the
`cam 65 is of slightly oval form, such pivotal movement of
`the locking part 64 results in gripping of the needle 2 by the
`cam 65, as shown in the view of FIG. 7A taken in the
`direction of the arrow Ain FIG. 7, and such gripping will be
`increased by any movement of the needle 2 in the direction
`tending to withdraw the needle from the needle tip protector
`61.
`What is claimed is:
`1. A catheter placement unit comprising a catheter having
`an axial bore, a catheter hub at one end of the catheter, an
`introducing needle having a pointed tip for introducing the
`catheter into a desired position in a patient's body, a needle
`hub on the needle remote from the tip for mounting the
`needle so that it extends through the catheter bore for
`introduction of the catheter into the patient's body and so
`that it can subsequently be withdrawn from the catheterbore
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`leaving the catheter in position in the patient's body, and a
`needle tip protector on the needle for shielding the needle tip
`when the needle has been withdrawn from the catheterbore,
`the needle tip protector including a locking device which is
`initially in an unlocked position permitting withdrawal of 5
`the needle from the catheterbore but which is arranged to be
`placed in a locked position, in which the locking device
`engages the outer surface of the needle, by withdrawal of the
`needle from the catheter bore so as to lock the needle tip
`protector on the needle in the shielding position, and in
`which the locking device comprises two co-operating lock
`ing parts which are pivotally interconnected and have oppos
`ing gripping portions thereon and which define a passage
`through which the needle extends to retain the locking
`device in the unlocked position when the needle is in its
`initial position extending through the catheter bore, biasing
`means for effecting relative pivoting of the locking parts
`when the needle is withdrawn from said passage on with
`drawal from the catheterbore so as to cause the needle to be
`gripped between said opposing gripping portions of said
`locking parts to place the locking device in the locked
`position and catheter engagement means on the locking parts
`for retaining the catheter hub on the needle when the locking
`device is in the unlocked position and for releasing the
`catheter hub from the needle by relative pivoting of the
`locking parts when the locking device is placed in the locked
`position such that separation of the catheter from the needle
`is prevented until the needle has been withdrawn from the
`catheter bore to trigger shielding of the needle tip.
`2. The unit according to claim 1, wherein one of the
`locking parts includes a tongue which is held in a depressed
`position by the needle when the needle extends through the
`catheter bore and which is released when the needle is
`withdrawn from the catheter bore and from said passage in
`order to permit the tongue to be moved by resilient action
`into a raised position in which it is retained by engagement
`with a retaining element and in which the needle is laterally
`offset from said passage to prevent re-introduction of the
`needle into the passage.
`3. The unit according to claim 1, wherein one of the
`locking parts includes a locking cam forming one of said
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`gripping portions which grips the needle when the needle is
`withdrawn from the catheterbore and from said passage and
`which is deflected by further withdrawal of the needle in
`such a manner as to provide increasing resistance to with
`drawal of the needle from the needle tip protector.
`4. The unit according to claim 1, wherein the catheter
`engagement means comprises retaining jaws for retaining
`the catheter hub therebetween to prevent separation of the
`catheter from the needle tip protector when the locking
`device is in the unlocked position and for releasing the
`catheter hub by movement apart of the jaws when the
`locking device is moved into the locked position on with
`drawal of the needle from the catheter bore and from said
`passage.
`5. The unit according to claim 1, wherein the needle tip
`protector is mounted on the needle such that, when the
`needle tip protector is in its shielding position, there is no
`interconnection between the needle hub and the needle tip
`protector other than that provided by the needle itself.
`6. The unit according to claim 1, wherein said biasing
`means comprises a leaf spring acting between the locking
`parts so as to be compressed when the locking device is held
`in the unlocked position by engagement of the needle within
`said passage.
`7. The unit according to claim 1, wherein said passage
`comprises an aperture extending through a transverse wall
`on one of the locking parts.
`8. The unit according to claim 1, wherein one of the
`locking parts includes an oval locking cam constituting one
`of said gripping portions which grip the needle when the
`needle is withdrawn from the catheter bore and from said
`passage.
`9. The unit according to claim 8, wherein the catheter
`engagement means comprises a retaining arm which
`engages the catheter hub when the locking device is in the
`unlocked position and which effects pivoting of the locking
`cam to grip the needle when the catheter hub is released on
`withdrawal of the needle from the catheter bore and from
`said passage.
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