United States Patent
`Cartmell et a1.
`
`[19]
`
`[11] Patent Number:
`
`‘
`
`4,710,175
`
`[45] Date of Patent:
`
`Dec. 1, 1987
`
`INTRAVENOUS INFUSION‘ASSEMBLY
`FORMED AS AN INTEGRAL PART
`
`[58] Field of Search ........................ 604/177, 164-170,
`604/283; 156/580.1
`
`[54]
`
`[75]
`
`[73]
`
`Inventors: Robert L. Cartmell, Kettering;
`Charles W.’Daugherty, Xenia; David
`B. Ireland, Dayton, all of Ohio
`
`Assignee: Deseret Medical, Inc., Franklin
`Lakes, NJ.
`
`[21]
`
`'Appl. No.: 829,457
`
`[22]
`
`Filed:
`
`Feb. 12, 1986
`
`Related US. Application Data
`Continuation of Ser. No. 524,728, Aug. 19, 1983, aban-
`doned.
`
`Int. Cl.4 ............................................... A61M 5/00
`US. Cl. ..................................... 604/177; 604/283
`
`[63]
`
`[51]
`[52]
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`604/177
`3,670,727 6/1972 Reiterman ........
`
`3,966,520 6/1976 Fallenbeck et a1
`156/5801
`8/1980 Sagae et a1. ................. 604/167
`4,217,895
`
`.. 604/167
`4,314,555
`1/1982 Sagae ...........
`6/1983 Genese ................................ 604/177
`4,389,210
`
`Primary Examiner—Dalton L. Truluck
`Attorney, Agent, or Firm—Robert P. Grindle
`
`[57]
`
`ABSTRACT
`
`An integral polyurethane winged catheter assembly
`formed by RF heating individual catheter parts is dis-
`closed.
`
`1 Claim, 6 Drawing Figures
`
`
`
`Nevro Corp.
`EX. 1015
`
`US. Patent No. 8,646,172
`
`Nevro Corp.
`Ex. 1015
`U.S. Patent No. 8,646,172
`
`

`

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`US. Patent
`
`Dec. 1,1987
`
`Sheet 2 of2
`
`4,710,175
`
`
`
`

`

`1
`
`4,710,175
`
`INTRAVENOUS INFUSION ASSEMBLY FORMED
`AS AN INTEGRAL PART
`
`This is a continuation of co-pending application Ser.
`No. 524,728 filed on Aug. 19, 1983 abandoned.
`BACKGROUND OF THE INVENTION
`
`5
`
`15
`
`This invention relates generally to intravenous infu-
`sion and, more particularly, to a winged catheter for 10
`intravenous infusion which is assembled from a plural-
`ity of polyurethane parts and formed into an integral
`unit by means of dielectric heating using radio fre-
`quency energy.
`Commonly used intravenous infusion assemblies
`comprise needle and catheter sets wherein a needle
`extends within a flexible catheter having so-called
`“wings” attached to the catheter assembly. For inser-
`tion, one grips the wings, squeezing them between the
`thumb and forefinger, to assist in accurately positioning 20
`the catheter sheathed needle into a desired vein.
`Once positioned, the needle is removed from the
`catheter leaving only the flexible catheter in place such
`that the vein is not likely to be ruptured as a result of
`minor relative movements between the infusion assem- 25
`bly and the vein. Two varieties-of combination needle/-
`catheter sets are shown respectiVely in US. Pat. No.
`3,094,122 issued Jan. 18, 1963 to Gauthier et al. and U.S.
`Pat. No. 4,362,156-issued Dec. 7, 1982 to Feller et al.
`It is important that the individual elements forming 30
`the infusion assembly be securely bonded together to
`prevent leakage from the assembly and detachment of
`the catheter. Many of the solutions passed through an
`intravenous infusion assembly may cause discomfort or
`pain if allowed to contact a patient’s skin. This is partic-
`ularly true with many chemotheraputic agents utilized
`to treat cancer patients. Even if the solution is not toxic,
`bacterial contamination is a problem once an opening
`appears in the intravenous infusion assembly. The com-
`plications of a detached catheter within a patient’s vein
`are potentially even graver. Accordingly, serious prob-
`lems can arise if the catheter assembly is not properly
`manufactured.
`
`35
`
`50
`
`A typical infusion assembly comprises a catheter, a
`winged catheter gripping member, a section of tubing 45
`and a fluid receiving hub. In the prior art, a variety of
`methods have been utilized to interconnect the parts
`making up such an assembly. The parts have been me-
`chanically interconnected by forcing a conical wedge
`into the proximal end of the catheter to lock the cathe-
`ter in the catheter hub. Such mechanical interconnec-
`tion is often referred to as “staking” or “swedging” and
`can be expensive and time consuming. Futhermore, the
`> presence of the wedge in the infusion stream creates
`turbulent flow which can interfere with metering the 55
`infusion liquid.
`The parts have also been glued together by means of
`an appropriate adhesive. However, gluing requires a
`biocompatible adhesive and is typically messy. Gluing
`also can lead to inadvertent blockage of a portion of the 60
`assembly passageway particularly when small gauge
`catheters are utilized.
`Solvent bonding has also been utilized. In solvent
`bonding, each of the parts is made from a material
`which is soluble in a particular solvent. When the s01- 65
`vent is applied to the parts and the parts are intermated,
`- dissolved surface portions of the two intermingle with
`one another'to form a bond. Unfortunately, solvent
`
`2
`bonding has proved to be only marginally reliable in
`preventing leakage. Solvent bonding also is expensive
`and time consuming when used for the assembly of
`intravenous infusion devices.
`
`One assembly means which has been used in forming
`a Foley catheter unit is by welding the individual parts
`together using dielectric heating cuased by radio fre-
`quency (RF) energy. However, radio frequency weld-
`ing or bonding has not been applied in the manufacture
`of intravenous infusion assemblies. Problems encoun-
`tered in RF bonding have centered around the frequen-
`cies and power levels utilized as well as the formation of
`the power applying electrodes. For example, if insuffi-
`cient power is applied to the parts, the welds or bonds
`are not reliable. 0n the other hand, excessive power can
`lead to arcing of the radio frequency energy at the
`electrodes and may damage the RF power supply and-
`/or cause the small openings of the passageways
`through the intravenous infusion assembly to be
`blocked.
`
`Thus, it is apparent that the need exists for an integral
`catheter intravenous infusion assembly which will pro-
`vide high reliability against leakage of possibly toxic
`materials onto a patient’s skin as well as detachment of
`the catheter from the intravenous infusion assembly.
`SUMMARY OF THE INVENTION
`
`In accordance with the present invention, a winged
`catheter assembly for intravenous infusion is formed as
`an integral unit from a plurality of polyurethane parts
`by means of welding the parts together using dielectric
`heating created by radio frequency energy. It has been
`found that catheter assemblies bonded by radio fre-
`quency heating in accordance with the present inven-
`tion are particularly advantageous because the assembly
`can be manufactured from parts made from polyure-
`thanes having the same or different shore hardness rat-
`ings and yet these parts can be integrally bonded to-
`gether such that there is intermingling of their constitu-
`ent polymers and they cannot be separated.
`In accordance with the present invention, a section of
`flexible polyurethane tubing is inserted into a polyure-
`thane fluid receiving hub and radio frequency energy is
`applied to the portion of the hub into which the tubing
`is inserted to heat the tubing and the hub such that they
`melt into one another to form a reliable weld or bond.
`Preferably, the fluid receiving hub includes tubing stop
`means, for example, an internal shoulder sized to engage
`the end of the tubing, for defining a tubing insertion
`point beyond which the tubing cannot be inserted into
`the hub.
`
`The opposite end of the tubing section is inserted into
`a generally cylindrical central portion of a polyurethane
`winged catheter gripping member and radio frequency
`energy is again applied to weld the two together as if
`the two were a single part. The catheter gripping mem—
`ber includes a pair of wings flexibly connected to the
`central portion and having a relaxed condition wherein
`the wings extend in a generally transverse direction to
`the central portion, yet the wings are sufficiently flexi-
`ble that they can be moved into facing engagement with
`one another for placement of the catheter into a selected
`vein. Finally, a generally cylindrical polyurethane cath-
`eter has it proximal end inserted into a canal in the
`generally cylindrical central portion of the catheter
`gripping member and is welded to it by the application
`of radio frequency energy with the catheter having its
`
`

`

`3
`tapered distal end extending from the gripping member
`for insertion into a vein.
`Such assembly and welding operations using radio
`frequency energy provide a winged catheter assembly
`which is an integral unit, i.e., the individual elements 5
`forming the infusion assembly are so bonded to one
`another that the polymers at the interface of two adja-
`cent parts are intermingled.
`A process for making an integral polyurethane
`winged catheter assembly for intravenous infusion in- 10
`eluding a fluid receiving hub, a winged catheter grip-
`ping member, tubing for interconnecting the hub to the
`gripping member, and a catheter, all of which are
`formed from polyurethane compounds, comprises the
`steps of interconnecting the individual parts together 15
`and applying the appropriate frequency and energy
`levels of RF energy to the sections of the parts receiv-
`ing the tubing and the catheter such that the polyure-
`thane compounds of the energized portions of the parts
`are heated to flow into one another to form an integral 20
`winged catheter assembly.
`It is, therefore, an object of the present invention to
`provide an improved intravenous infusion assembly
`which is formed as an integral unit from a plurality of
`parts made from polyurethane compounds of the same 25
`or different hardness with the individual parts being
`; assembled and welded to form an integral unit by means
`of the application of the appropriate frequency and
`energy levels of radio frequency energy to interengag-
`- ing portions of the assembly to thereby fuse the interen~ 30
`gaging portions of the respective parts and firmly weld
`them to one another.
`.
`Other objects and advantages of the invention will be
`apparent from the following description, the accompa-
`nying drawings and the appended claims.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`35
`
`.
`
`FIG. 1 is a plan view of an intravenous infusion as4
`,sembly in accordance with the present invention.
`FIG. 2 is a sectional view of the fluid infusion hub of 40
`FIG. 1 taken along the line 2—2.
`FIG. 3 is a sectional view of the central portion of the
`catheter gripping member of FIG. 1 taken along the line
`3—3.
`
`FIG. 4 is a side view of apparatus for engaging a fluid 45
`infusion hub and applying radio frequency energy to a
`section of that hub into which a section of tubing has
`been inserted.
`
`FIG. 5 is a side view of apparatus for applying radio
`frequency energy to a winged catheter gripping mem- 50
`her to thereby weld the member to polyurethane tubing
`inserted into one end.
`FIG. 6 shows an end view of electrodes for conduct-
`ing radio frequency energy to the fluid infusion hub and
`tubing combination.
`
`55
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`'In FIG. 1, an intravenous infusion assembly 100 in
`accordance with the present invention comprises a fluid 60
`receiving hub 102, a section of flexible tubing 104, a
`winged catheter gripping member 106 and a catheter
`108 all formed into an integral unit by means of radio
`frequency welding or bonding as will be described here-
`inafter.
`The fluid receiving hub 102, shown in cross-section in
`FIG. 2, comprises a hollow, generally cylindrical, body
`molded from a relatively rigid polyurethane compound.
`
`65
`
`4,710,175
`
`4
`the polyurethane forming the hub has a
`Typically,
`Shore Durometer D hardness of about 50 to 75 and the
`polyurethane forming the tubing has a Shore Durome-
`ter A of about 75 to 95.
`
`The proximal end of the hub 102 has a collar 110 with
`radially and circumferentially extending lugs 112 that
`may be used with conventional equipment employing
`Luer locks for external connection to a source of infu-
`sion fluid. Reinforcing ribs 114 run approximately two-
`thirds of the way along the hub from the collar 110
`toward the distal end of the hub.
`
`The hub 102 comprises a primary fluid receiving
`cavity 116 opening to its proximal end and a tubing
`receiving canal 118 opening to the distal end of the hub
`102. The primary fluid receiving cavity 116 and the
`tubing receiving canal 118 are interconnected by a di-
`ameter reducing frustoconical section 120 and a gener-
`ally cylindrical interconnecting canal 122 which is of a
`smaller diameter than the diameter of the generally
`cylindrical tubing receiving canal 118. The reduced
`diameter canal 122 forms a tubing stop means or shoul-
`der 124 such that when the tubing 104 is inserted into
`the tubing receiving canal 118, it is extended only until
`it engages the shoulder 124 to provide a selected or
`defined length of the tubing 104 extending into the hub
`102.
`
`As shown in FIG. 1, the winged catheter gripping
`member 106 comprises a generally cylindrical central
`portion 126 to which the wings 127 are flexibly con-
`nected. The gripping member is preferably formed from
`a relatively soft polyurethane e.g., one having a Shore
`Durometer A hardness of about 75 to 90 such that the
`wings 127, as shown in FIG. 1, can be folded upwardly
`into facing engagement with one another and be firmly
`gripped between the thumb and forefinger of a person
`inserting the catheter assembly into a vein of a patient.
`A cannula or needle (not shown) is included within the
`catheter assembly 100 for insertion of the catheter 108
`into a vein as is well known in the art.
`The generally cylindrical central portion 126 of the
`member 106, shown in cross-section in FIG. 3, includes
`a first opening 128 toward its proximal end sized to
`frictionally receive the distal end of the tubing 104. The
`exact insertion depth of the tubing 104 into the opening
`128 is not critical. It is only necessary that the tubing
`104 extend a sufficient distance into the passageway 128
`such that it may be securely welded by means of dielec-
`tric heating generated by RF energy applied to the
`central portion 126 as will be described hereinafter.
`The distal end of the central portion 126 includes a
`downsized opening 130 which is sized to receive the
`proximal end of the catheter 108. The catheter 108 may
`be inserted a varying depth into the opening 130 and,
`again, the only requirement is that a sufficient insertion
`depth be made such that the catheter 108 and the sur-
`rounding portion of the central section 128 forming the
`opening 130 may be fumly welded to one another by
`means of dielectric heating. A particular advantage of
`the present invention is that an integral catheter assem-
`bly can be formed from polyurethane elements without
`unduly restricting the nature of the polyurethane which
`forms the catheter. Thus, the catheter can be formed
`from a polyurethane which is hard enough to be in-
`serted through the skin on a cannula but is sufficiently
`pliable as to not scratch or damage the inside wall of a
`vein or artery into which the catheter is inserted. Poly-
`urethanes used for this purpose usually have a Shore
`Durometer D hardness of about 55 to 70.
`
`

`

`4,710,175
`
`6
`hub 102 somewhat less restrictive since the member 136
`
`maintains the opening into the tubing 104 in spite of
`marginal excesses of heating generated by the RF en-
`ergy passing through the polyurethane materials.
`FIG. 5 illustrates bonding tubing 104 into the central
`portion of the gripping member 106. There, the ground
`electrode 142 is lowered to engage the central cylindri-
`cal portion 126 of the winged catheter gripping assem-
`bly 106 at the location where the tubing 104 has been
`inserted into the member 106. RF energy is then applied
`through the terminal 134 via wire 135 to pin 136 with
`ground being applied to the base 144 of the jig and
`electrode 142 such that radio frequency energy passes
`through the gripping member 106 and the tubing 104.
`It is critical that a power level be used which forms
`the objective integral bond without blocking the cathe-
`ter. In the case of small gauge catheters, this is espe~
`cially critical and the following power levels at a fre-
`quency of 63 mHz have been found to provide a reliably
`secure weld of the catheter to the cylindrical member
`126 without providing blockage of the small opening of
`the catheter.
`
`Catheter
`Gauge
`16
`18
`20
`22
`24
`
`Power Level t
`15% at 5 secs
`200 watts
`200 watts
`200 watts
`200 watts
`200 watts
`
`
`
`
`
`5
`FIG. 4 shows a jig for welding the tubing 104 to the
`hub 102 and FIG. 5 shows a jig for welding the tubing
`104 into the central portion 126 of the winged catheter
`gripping member 106. RF energy from a Solidyne KH
`8 RF generator from Solidyne, Inc. (not shown) is con-
`nected to terminal lugs 132 and 134 of the jigs shown in
`FIGS. 4 and 5, respectively which in turn are connected
`to a metal pin 136 on which the catheter assembly is
`mounted as it is welded. An alternating current is deliv-
`ered to the pin 136 by the generator which causes the
`polarity of the pin to rapidly oscillate between a highly
`positive and a highly negative polarity with respect to
`- ground. Thus, an alternating electric field is set up be-
`tween the pin 136 and the electrodes 140 which are
`grounded.
`Because it is difficult to maintain uniform voltage
`distribution over large areas and a relatively small bond
`area is sufficient to form the assembly into an integral
`unit, electrodes 140 are designed with smaller dimen-
`sion tips 141 where the field is concentrated. The por-
`tions of the catheter assembly in the alternating field
`between the electrode tips 141 heat in a known manner.
`It is not essential that there be a space between the
`catheter assembly 100 and the groundelectrodes 140 to
`prevent arcing. Sharp points and edges should be
`avoided in the electrodes wherever possible since these
`are the first places breakdown occurs.
`For welding the tubing 104 to the hub 102, a gener-
`ally cylindrical pin 136 extends from the framework 138
`of the jig shown in FIG. 4 with the generally cylindrical
`pin 136 being connected to the RF generator. The
`ground electrodes 141, an end view of which is shown
`in FIG. 6, are closed to engage one another and form an
`intimate contact from the forward portion of the hub
`102 into which the tubing 104 has been inserted.
`Bonding conditions will vary depending on the char-
`acteristics of the specific polyurethanes used, the elec-
`trode construction and the surroundings. The maximum
`voltage that can be used is limited by the voltage break-
`. down characteristics.
`~
`As a general rule, the frequency should be as high as
`possible so that the lowest voltage can be employed.
`However, at higher frequencies the equipment is more
`costly, it is difficult to deliver the power to the'material
`as efficiently and it is more difficult to maintain uniform
`voltage distribution.
`It has been found that RF energy at l to 100 mHz,
`preferably 25 to 70 mHz and most preferably 55 to 65
`mHz is preferred for bonding the polyurethane parts of
`the winged catheter assembly of the present invention.
`However, there may be small changes in the preferred
`frequency as the polyurethane compositions change.
`For bonding, the RF energy is connected at a power
`level of about 10 to 5,000 watts for a period of approxi~
`mately 0.1 to 60 seconds preferably 100 to 300 watts for
`2 to 11 seconds and actually at 200 watts for 4 seconds.
`It should be understood that the period can vary from 3
`to 7 seconds depending upon the specific composition
`of the polyurethane compounds making up the tubing
`104 and the hub 102 as well as the specific size and
`thickness of the hub and tubing.
`The RF field is maintained for a period sufficient to
`melt the parts of the assembly only in the vicinity of the
`desired bond such that the polyurethanes forming the
`individual elements mingle but without loosing their
`form or blocking the channel through the assembly.
`The use of the electrode pin 136 makes the upper limits
`of the RF power applied to weld the tubing 104 to the
`
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`While the process and product herein described con-
`stitute preferred embodiments of the invention, it is to
`be understood that the invention is not limited to this
`precise process and product and that changes may be
`made therein without departing from the scope of the
`invention which is defined in the appended claims.
`What is claimed is:
`1. A unitary winged catheter assembly comprised
`entirely of a plurality of polyurethane parts of varying
`degrees of hardness, said parts being dielectrically
`welded together into said unitary assembly, character-
`ized by
`(a) a fluid receiving hub for said assembly;
`(b) said hub having a fluid receiving first end and a
`second end;
`(c) said hub being comprised of a substantially hard
`rigid polyurethane material having a Shore D
`hardness within the range of between about 50 and
`75;
`(d) a fluid canal in said hub, said canal extending from
`said first end to said second end;
`(e) said canal having a reduced diameter portion adja-
`cent said second end to define a tubing stop in said
`hub canal;
`(f) a length of substantially soft flexible polyurethane
`tubing having a Shore A hardness within the range
`of between about 75 and 95, said tubing having a
`first end and a second end;
`(g) the first end of said tubing extending into said
`second end of said hub to said tubing stop and
`forming a first joint for said assembly;
`(h) said first end of said tubing and said second end of
`said hub having internal diameters substantially
`equal at said tubing stop;
`(i) a gripping member comprised of a substantially
`soft flexible polyurethane having a Shore A hard-
`
`

`

`7
`ness within the range of between about 75 and 90,
`and having a passageway extending therethrough
`from a first end of said gripping member to a sec-
`ond end thereof;
`(i) the internal diameter of said gripping member
`passageway receiving in the first end thereof the
`said second end of said tubing, and forming a sec-
`ond joint for said assembly;
`(k) a pair of substantially soft flexible polyurethane
`wings having a Shore A hardness within the range
`of between about 75 and 90 and positioned on said
`gripping member, and movable from a first position
`transverse to the axis of said passageway through
`said gripping member to a second position with
`said wings in facing relation to each other;
`(1) a substantially rigid polyurethane catheter having
`a Shore D hardness within the range of between
`about 55 and 70 with a first end and a second end,
`
`8
`and having the second end tapered for insertion
`into a vein;
`(m) the first end of said catheter being inserted into
`the said second end of said passageway of said
`gripping member to form a third joint for said
`assembly;
`(11) the internal diameter of said gripping member
`passageway being large enough to receive in the
`second end thereof the said first end of said cathe-
`ter for said third joint;
`(0) the mating surfaces of said first, second and third
`joints being joined together by dielectric welding
`for comingling the components of said mating sur-
`faces; and
`(p) the internal diameters of said first, second and
`third joints being of sufficient diameter for receiv-
`ing a dielectric electrode for said dielectric weld-
`ing.
`‘
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`4,710,175
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