AU649832B2 - Cannula insertion member - Google Patents

Description

6498 3 2 p00011 Regulation 3.2

AUSTRALIA

Patents Act, 1990 COMPLETE SPECIFICATION FOR, A STANDARD PATENT original i* TO 5E COMPLETED BY THE APPLICANT *Q a a a a aa. *a a a *0S* a NAME OF APPLICANT: ACTUAL INVENTOR(S): ADDRESS FOR SERVICE: BAXTER INTERNATIONAL INC.

STEVEN C. JEPSON, THOMAS E. DUDAR, BRIAN D. ZDEB and VINCE C. DESECNI Peter Maxwell Associates Blaxiand House, Suite 10, 5 Ross Street, NORTH PARRAMATTA NSW 2151 CANNULA INSERTION MEMBER INVENTION TITLE: The following statement is a full description of this invention, including the best method of performing it know to me:- -2- This invention pertains to coupling systems usable to transfer materials from one flow conduit to another. More particularly, the invention pertains to a cannula insertion member adapted to be inserted into an injection site as well as to a cannula and injection site in combination.

Injection sites usable with pointed cannulae having long been known.. For example, such sites can be formed with a housing having a fluid flow path therein. A septum is positioned in the housing closing the fluid flow path.

One injection site usable with a piercing cannula is disclosed in U.S. Patent 4,412,573 entitled "Injection Site".

The pointed cannula can be forced through the septum into fluid flow communication with the flow path in the housing. Known injection sites usable with a piercing cannula can be physically damaged by repetitive piercing 15 caused by the sharp cannula. This damage, known as coring or laceration, can result in subsequent leakage.

Due to problems associated with infectious agents, personnel using such pointed cannulae do so with great care.

Notwith&-'anding careful and prudent practice, from time to 20 time, accidents do occur and individuals using such pointed cannulae jab themselves.

Injection sites usable with a blunt cannula are also known. For example, U.S. Patent No. 4,197,848 entitled "Closed Urinary Irrigation Site" discloses one such Injection site. That injection site is a relatively low pressure device having a relatively thin, molded, sealing memlbr. The sealing member has an opening therethrough.

A blunt cannulae can be forced through the sealing member placing the cannuJlae into fluid flow communication with a fluid flow pathway in the injection site.

Injection sites of the type noted above usable with a blunt cannula have the advantage that the blunt caninula will not pierce the skin of a user.

Preferably, a pre-slit injection site usable with a blunt cannula will provide a reasonable level of insertion force such that health care personnel will readily be able to insert the blunt cannula, yet the cannula will not easily fall from or drop out of contact with the septum.

According to one aspect of the Invention there Is provided a blunt cannula insertion member adapted to be inserted into a pre-slit injection site, said insertion member comprising: at least one tube defining a flu:W flow path therein, said tube having a distal end region for penetrating said injection site; said tube having an aperture in an exterior surface In said distal end region through which fluid can flow to or from said flui~d flow path; and 444 said tube including means for reducing the inser~tion force, *~.00 said means including longitudIr~ally oriented grooves in the exterior surface of said tube and a tapered surface on a least part of said distal end region, the taper terminating at a position which Is not distal of said aperture.

According to another aspect of the invention there is provided a blunt cannula insertion member adapted to be inserted into a pre-slit injection site, said insertion member comprising: at least one tube defl.ning a fluid flow path therein, said -tube having a distal end region for -4penetrating said injection site; said tube having at least one aperture in an external surface in said distal end region through which fluid can flow to or from said fluid flow path; and said distal end region including a tapered exterior surface to facilitate insertion, the taper terminating at a position which is not distal of said aperture, said tube also including a generally cylindrical region extending from said tapered distal end region for entering into said injection site behind said distal end region and reducing kick back during insertion.

According to a further aspect of the invention there is provided a blunt cannula insertion member adapted totoo* 9, 9 9..

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99: .9 9 9 9 *9 9 9 9 be inserted into a pre-slit resealable injection site, said insertion member comprising: a tube having a central ',,ore throughout said tube, defining a fluid flow path therein, said tube having a distal end region for penetrating said injection site; said distal end region defining at Iciast one aperture in the distal end of said distal end regi1on through which fluid can flow to or fromi said fluid flow path; said distal end region including a tapered exterior surface to facilitate insertion; said distal end further including a radiused tip adjacent said tapered surface, said radiused tip reducing the Insertion force into and assisting in locdting the slit of said injection site, upon contacting the injection site with said cannula.

According to a still further aspect of the invention there is provided a blunt cannula insertion member adapted to be Inserted into a pre-slit resealable injection site, said insertion member comprising: a tube having a central bore throughout said tube defining a fluid flow path there~kn, said tube having a distal end region terminating in a blun~t radiused tip for penetrating said injection site; said distal end region defining at least one aperture in the distal end of said distal end region through which fluid can flow to or from said fluid flow path; said distal end region Including a tapered surface; and said~ tube also including a generally cylindrical region extending from said distal end region for entering into said injection site behind said distal end region.

The invention further provides a cannula and injection site in combination comprising: a resealable injection site having a housing defining a fluid flow path therein and having a pre-slit sealing means for sealing said housing; a blunt cannula having a tube with a central bore throughout said tube, defining a fluid flow path therein, said tube extending through said sealing means to establish a sealed fluid flow connection with said iajection site, said tube having a distal end region extending beyond said injection site with a tapered surface and a blunt radiused tip; said tube having a generally cylindrical region merging with said tapered distal end region, said cylindrical region being received within said sealing means to provide reduced kick back and increased tug resistance; and said sealing means sealing the injection site upon removal of the cannula from 9 the sealing means.

:The cannula may carry a locking member for lockingly 999999 9 engaging the injection site when the cannula extends through the opening of the injection site.

:20 The locking member can include a Luer-type twist lock fitting. Alternatively, the locking member can include slidably engageable members which are responsive to axial movement of the injection site and the cannula toward one another.

The blunt cannula may be provide& with features that facilitate insertion into the injection site, enhance fluid flow or dispersion, increase tug resistance; and reduce kickback.

in particular, one embodiment off the cannula Includes a tube with a plurality of elongate discharge slots adjacent the distal end. The fluid changes direction bs it passes laterally through the slots and out of the tube. The flow area of the slots exceeds the flow area inside the tube.

This slot structure enhances fluid flow and inspersion characteristics. In addition, the slots decrease the contact surface area on the tube exterior so as to facilitate insertion.

In a further modification, the cannula includes a lead post on the tube distal end to guide the cannula through the slit In the injection site.

In another caniiula embodiment, the tube is generally cylindrical and the fluid discharges directly from an open end of the tube. The exterior surface of the tube is a provided with grooves to reduce the contact surface area, In still another cannula embodiment, the tube has a cylindrical portion and a tapered distal end portion which are eac~h about eq~ual in length, The taper facilitates fee: 20 insertion, and the remaining cylindrical portion reduced kickback.

In yet another embodiment, the cannula includes an 6~RS*annular barb which functions to reduce kickback.

Other advantages of a blunt plastic cannula In accordance with the invention, relative to conventional steel needles include a Iv jher fluid flow rate capacity and a simpler one-piece plastic design.

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings in which:- Fig. i is a side elevational view, partly in section, nt a prior art pre-slit in action site and an associated blunt cannula; Fig. 2A is a view in perspective of a catheter positioned i the hand of a patient with a pre-slit injection site positioned adjacent thereto; Fig. 2B is a perspective view of the catheter of Fig. 2A with a pre-slit injection site rotatably affixed thereto; Fig. 3 is an enlarged side elevational view in a 15 section of a pre-slit injection site formed on a body having a luer twist-lock type connector for coupling to a catheter; Fig. 4A is an exploded view of a pre-slit injection site, a shielded blunt cannula and a 20 syringe prior to being cupled together; see oFig. 4B is an enlarged, side elevational view in section of the pre-slit injection site, the shielded bluat cannula land the syringe of Fig. 4A coupled together to form a sealed fluid flow system; Fig. 5A is a view in perspective of a pre-slit injection site prior to engaging a blunt cannula carrying a locking member; -9- Fig. SB is an enlarged side elevational view, partly broken away, illustrating the interrelationship between the pre-slit injection site and the blunt cannula of Fig. SA; Fig. 6 is an overall view of a container, an associated solution administration set and a pre-slit injection site; Fig. 7 is an enlarged side elevational view, partly broken away illustrating the relationship between selected elements of Fig. 6; Fig. 8 is a side elevational view, partly broken away illustrating an alternative shielded 00 00 15 cannula; 6 Flo.0 is a side elevational view, partly in 4 of section, of a pre-slit injection site 0 mounted on a fragment of a solution container; 20 Fig. 10 is a side elevational view of a fragment of 0 *0* solution container carrying, as a single 0000 S..port, a pre-slit injection site; 11 is a side elevational view of the injection site and the fragmentary container of Fig.

10 prior to being engaged with a shielded cannula carried by a syringe; Fig. 12 is an enlarged side elevational view, ~partly in section, of a coupling syotem W3 n! with a pre-slit injection site partly Fig. 13 FXg. 14 Fig. 15 Fig. 16 S* I 15

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*o *Q o* coupled to a blunt cannula; is an enlarged cide elevational view, partly in section, of the coupling system of Fig. 12 subsequent to engagement of the two coupling members; is a side elevational view, partly broken away, of a spike connector carrying a preslit injection site; is an enlarged side elevational view of a Y-connector in section carrying a pre-slit injection site; is an enlarged fragmentary side elevational view in section of a coupling member carrying a pre-slit injection site where the slit extends only partway through the septum; is a perspective view of a burette solution administration set carrying a pre-sllt injection site; is a view of part of a burette solution administra'tion set carrying a pre"slit injection site being coupled to a shielded blunt cannula; is a step in the method of making a preslit injection site; is another step in the method of making a pre-slit injection site; is an initial phase of a final step in making u ,re-slit injection site; Fig. 17 Fig. 18 Fig. 19 Fig. 20 Pig. 21 T QA -11- Fig. 22 Fig. 23 Fig. 24 Fig. 25 Fig. 26 Pig. 27 is an intermediate phase of the final step in a method of making a pre-slit injection site; is a final phase ot the final step in a method of making a pre-slit injection site; illustrates an initial phase in an alternative step cf making a pre-slit injection site; illustrates a final phase of the alternative step in a method of making an iniection site; illustrates yet another alternative step in a method of making a pre-slit injection site; is an enlarged, fragmentary cross-sectional view of another embodiment of an injection site; is a cross-section view taken generally along the plane 28-28 in Fig. 27; is an end view of another embodiment of the cannula in accordance with the present invention; iA a cros-sectlion view taken generally along the plane 30-30 in Fig. 29; is an end view of another embodiment of the cannula in acce.dance with the present invention; is a cross-sectional view taken generally along the plane 32-32 in Fig. 31; 20 ft.

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2 cP Fig. 28 Fig. 29 Fig. 30 Fig. 31 Fig. 32 -12- Fig. 33 Fig. 34 5 *B a SO 0 oo 20 a. a to a 9 so:s a a., Fig. 35 Fig. 36 Fig. 37 Fig. 38 Fig, 39 Fig. 40 Fig. 41 Fig. 42 Fig. 4 Fig. 44 Fig. 45 is a cross-sectional view taken generally along the plane 33-33 in Fig, 32is an end view o& another embodiment of the cannula in accordance with the present invention; is a fiagmentary, side elevational view of the embodiment of the cannula illustrated lai Fig, 34; is a cross-sectional view teka generally along the plane 36-36 in Fig. 34; is a cross-sectional view taken generally along the plane 37-37 in Fig. 36; is an end view of another embodiment of the cannula according to the present invintion; is a cross-sectional view taken generally along the plane 39-39 in Fig. 38; is a cross-sectional view taker, generally along the plane 40-40 in Fig. 39; is an end view of another embodiment of the cannula according to the present invention; is a cross-sectional view taken generally along the plane 42-42 in Fig. 41; is an end view of another embodiment of the cannula according to the present invention; is a cross-sectional view taken generally along the plane 44-44 in Fig. 43; and is a view in section of another insertion member for a blunt cannula.

-13- Detailed Descrintion of the Preferred Embodiments While this invention is susceptible of embodiment in many different forms, there are shown in the drawing and will be described herein in detail specific embodiments thereof with'the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.

A prior art pre-slit injection site 10 and associated blunt cannula 12 are illustrated in Figure 1.

The prior art injection site 10 has a cylindrical .housing 14 with a fluid flow path 16 therethrough. A first end 18 of the housing 14 is closed with a relatively thin disc-shaped resealable member 20. The member 20 has a resealable opening 22 therein.

The member 20 is a molded septum with an integrally formed skirt 20a. The skirt 20a is oriented generally perpendicular to the portion of the septum with the opening 22.

The cannula 12 includes a body portion 24 which carries at a first end a hollow, cylindrical, blunt piercing member 26. As the cannula 12 is moved in a direction 28 toward the first end 18 of the injection

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S. 25 site 10, the member 26 slidably engages the opening 22.

The sealing member 20 is then deformed adjacent the openirg 22 and the number 26 extends into the flow path 16. A fluid flow path through the cannula 12 will then be in fluid flow communication with the flow path 16 via 30 the hollow piercing member 26.

In contradistinction to the prior art pre-slit injection site 10 of Figure 1, Figures 2A and 2B illustrate a pre-slit injection site 34 being coupled to a peripheral venous catheter 36. The catheter 36 is shown in fluid flow communication with a vein in a hand i of a patient. The catheter 36 carries at a proximal end 38 a luer-type female twist lock connector 41.

The pre-slit injection site 34 is formed with The pr l3 -14a cylindrical housing 40 having a first end 42 and a second end 44.

Carried by the housing 40, adjacent the second end 44 is a hollow cylindrical fluid flow member 46.

The member 46 slidably engages a receiving member in the housing 38 of the catheter 36, thereby providing a sterile fluid flow coupling as is well known and conventional.

A plurality of internal male luer-type threads 48 is carried by the housing 40 adjacent the second end 44. The threads 48 will engage the flange member 41 when the injection site 34 is rotated in a direction When so coupled together, the catheter 36 and the injection site 40 provide a sealed coupling through which fluids may be injected into the vein of the hand

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Figure 3 illustrates, in section, further details of the injection site 34. A resealable septum 52 is carried by the first end 42 of the housing The septum 52 includes first and second spaced apart surfaces 54 and 56 respectively. The surface 54 has been forced into a dome-like shape by annular, U-shaped, swaged end members 58 carried by the first end 42. The dome-like shape of the surface 54 can extend beyond a 25 surface 42a of the first end 42. This facilitates cleaning the surface 54.

The septum 52 has a generally cylindrical 0 shape. The septum 52 can be frmed of a latex or synthetic rubber material. Alternately, the septum can 30 be formed of a thermoplastic elastimer. The material "used for the septum 52 should be non-toxic and o. sterilizable such as by means of radiation, steam or Ethylene Oxide.

Because the septum 52 is generally cylindrical 35 in shape, it can be die-cut from a sheet,, cut from an extruded rod or molded. The septum 52 can have an exemplary diameter on the order of .30 inches (0.762 centimeters). The height of the septum 52 can be, for u I-u example, on the order of centimeters).

.125 inches (.3175 The first end 42 is also formed with a tapered interior surface 60 which terminates -in an -annular channel 62. The tapered interior surface 60 has a taper in a range of 5 degrees to 20 degrees. Preferably, the taper will be on the order of 12 degrees. With the indicated size of the above noted exemplary septum 52 and a 12 degree taper, diametric resealing compression of the septum 52 adjacent, the channel 62 is on the order of *0 o 0 2 0 0 :25 *ot 0 35 a o as s* The. channel 62 is bounded in part by a septum supporting ridge 62a. The channel 62 can typically have a depth in a range of .050-.070 inches (.127-.1778 centimeters) A peripheral surface 64 of the septum 52 slidably engages the tapered interior surface 60 as the septum 52 slides into the first end 42. The annular channel 62 which underlies the interior peripheral surface 56 of the septum 52 is provided to permit the septum 52 to deform when a blunt cannula is inserted through an opening 66 therein.

The housing 40 is' also formed with a fluid flow path 68 such that fluids injected via a blunt cannula inserted through the resealable opening 66 can flow into the catheter 36 for delivery to hand H of the patient.

The swaged end members 58 apply axial forces to the septum 52 thereby creating the domed exterior peripheral surface 54. The axial forces applied by the end members 58 slightly deform the regions 52a and 52b.

In contradistinction, the tapered internal surface applies radially directed forces to the septum 52, thereby forcing the opening 66 into a resealed condition.

In an alternate embodiment, the surface 52 could be Zormed as a flat, as opposed to a domed, surface.

-16- Once the injection site 34 is lockingly engaged with the catheter 36, a sealed system is formed through which fluids can be infused into the catheter 36. The resealable septum 52 closes the fluid flow path 68.

Figures 4A and 4B illustrate in combination the injection site 34, a blunt shielded cannula 80 and a syringe of a conventional type 82. The syringe 82, as is well known, can be formed with a cylindrical hollow end 84 which carries a male luer-type twist lock thread 86. A hollow centrally located cylindrical fluid flow member 88 is in fluid flow communication with an interior region 90 of the syringe 82.

The shielded blunt cannula 80 carries at a first end 92 a female luer twist-lock flange 94. The flange 94 will slidably engage the threads 86 of the end 84. Hence, the shielded blunt cannula 80 can be locked to the syringe 82 forming a closed fluid flow pathway.

The shielded cannula 80 could alternately be formed fixedly attached to the syringe 82.

The shielded blunt cannula 80 carries a cylindrical'hollow protective shield 96 which surrounds a centrally located hollow, elongated cylindrical blunt piercing member 98. The cylindrical blunt piercing 25 .iember 98 has a total length on the order of three times the thickness of the septum 52 in order to ensure complete penetration. The cylindrical blunt piercing member 98 has a diameter on the order of 1/3 the diameter of the sentum 52. The sh..eld 96 is desirable 30 and useful for maintaining the piercing member 98 in an aseptic condition by preventing touch contamination t: prior to the shielded cannula 80 engaging the pre-slit Sseptum 52. Also, the shield helps to align the piercing member with the pre-slit septum.

The cylindrical blunt piercing member 98 can slidably engage the pre-slit septum 52, best illustrated in Figure 4B, thereby extending through the preformed opening 66 therein. As illustrated in Figure 4B, when I I v -17the piercing member 98 slidably engages and pierces the septum 52, the region 52a deforms by expanding into and filling, at least in part, the annular channel 62.

The deformation facilitates insertion of the piercing member 98 through the slit 66. Subsequent to the piercing member 98 slidably engaging "the injection site 34, the interior region 90 of the syringe 82 is in fluid flow communication with the flow path 68 of the injection site 34 via flow paths 88a and 98a respectively of the syringe and the blunt piercing member 98.

In this engagement condition, the septum 52 seals completely around the piercing member 98. Hence, exterior gases, liquids or airborne matter will be excluded from the channel 68.

Subsequent to infusing fluid from the syringe 82 into the fluid flow pathway 68, hence into the catheter 36 and the hand H of the patient, the syringe 82 with lockingly engaged shielded cannula 80 can be slidably withdrawn from the injection site 34.

Subsequent to this withdrawal, the septum 52 reseals the opening 66 therein.

The opening 66 will repeatedly reseal, when the piercing member 98 is removed, provided that the 25 pressure (in the septum 52 of the opening 66) created by interaction of the septum material properties and compression supplied by the housing exceeds the pressure challenge of the fluid contained within. Blunt cannula do not haphazardly core, lacerate, or ctherwise damage the sealing interface 66 as conventional needles do, thereby allowing repeatable resealability. However, septum material properties, thickness, and compression allow resealability for a finite number of conventional needle insertions. The combination injection site 34 and catheter 36 then return to its pre-infusion, sealed condition.

Figures 5A and 5B illustrate the pre-slit

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4 injection site 34 used in combination with a blunt a*

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a

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-18cannula 80a. The cannula 80a includes a hollow body portion 92a with a Luer flange 94a, a piercing member 98a, and manually operable elongated locking members 100a and 100b. Alternately, a tubing member could be affixed to the hollow body portion 92.

Curved end regions 100c of the members 100a and 100b slidably engage the second end 44 of the housing 40 when the piercing member 98a of the blunt cannula 80a has been forced through the pre-formed opening 66, best illustrated in Figure 5B. The embodiment illustrated in Figures 5A and 5B has the advantage that the infusion cannula 80a cannot accidentally disengage from the pre-slit septum 34 during the fluid infusion process. It will be understood that while spring-like deflecting members 100a and 100b are illustrated in Figures SA and 5B that other forms of locking members are within the spirit and scope of the present invention.

Figure 6 illustrates an alternate pre-slit injection site 34a. A tubing member 102 can be fixedly attached to the cylindrical hollow fluid flow member 46, The embodiment 34a of Figure 6 utilizes the same structure for the septum 52 including the tapered surface 60 and the underlying annular channel 62 as does 25 the embodiment 34 in Figure 3. The shielded cannula can be utilized with the injection site 34a as previously described.

In the event that it is desirable to infuse solution from a container 104 with a connectional port 30 106, a fluid administration set 110 of a conventional variety may be utilized. The set 110 includes a spike connector 112 at a first end. The spike connector 112 is designed to pierce the par 106 of the container 104.

The set 110 can also carry a slidably engageable S 35 connector 114 of a known type at a second end. As illustrated in Figure 7, the connector 114 can slidably engage the hollow cylindrical member 92 of the shielded Scannula 80, thereby placing the interior fluid of the -19container 104 into fluid communication with the tubing member 102.

Figure 8 illustrates yet another alternate to the shielded cannula 80. The piercing member 98 carries a tubing member 118 fixedly attached thereto.

The tubing member 118 could be coupled at a second end to a container such as the container 104.

The present pre-slit injection site can be directly affixed to a container 120 as illustrated in Figure 9. The 'container 120 includes a rigid hollow cylindrical access port 122 affixed thereto. The access port 122 includes a fluid flow channel 124 in fluid flow communication with the interior of the container 120.

Sealingly affixed to the port 122 is a pre-slit injection site 126.

The site 126 includes a cylindrical housing 128 which carries at a first end 130 a septum 132 with a slit 134 formed therein. The first end 130 has been swaged to form an annular U-shaped retaining member 136.

The retaining member 136 in turn forms a domed exterior peripheral surface 138 on the septum 132.

The first end 130 also includes a tapered interior force applying surface 140 and an annular channel 142 underlying the septum 132. As discussed oS 25 previously, the channel 142 provides a space into which the septum 132 can deform when a blunt cannula is forced i'"I through the resealable opening 134.

Further, as illustrated in Figure 9, the injection site 126 can be covered by a removable cover 30 146 of a type used with the conventional port 106 of the bag 104.

o pt""s While the bag 120 is illustrated formed with two ports, the conventional pierceable port 106 and the pre-slit injection site 126, it will be understood that as an alternate (F.igure 10), a container 150 could be formed which includes only the pre-slit injection port 126. The removable cover 146 could be used in combination with the container 150.

As illustrated in Figure 11, the pre-slit injection site 126 can be utilized for the purpose of injecting fluid from the syringe 82: coupled to the shielded cannula 80, into the container 150. When so utilized, the blunt piercing member 98 is used to place the interior fluid containing region 90 of the syringe Sinto fluid flow communication with the interior of the container 150.

Figures 12 and 13 illustrate a fluid flow coupling system 151 having as a. first element a pre-slit injection site 126a. The site 126a is the same as the.

site 126 except for a plurality of exterior threads 153 formed on an exterior peripheral surface 155 of the housing 128a. A second element of the coupling system 151 is a shielded blunt cannula 157.

The shielded blunt cannula 157 is sealingly affixed to a flexible tubing member 159 by means of a proximal hollow cylindrical member 161. The member 161 extends into a hollow cylindrical shield 163 to form a blunt piercing member 165.

The shield 163 carries, on an interior peripheral surface, a set of coupling threads 165. The threads 165 match the threads 153.

:"The two connector elements 126a and 157

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25 slidably engage one another when the shielded cannula 157 moves in an axial direction 167 toward the injection site 126a. The blunt piercing member 165 penetrates the septum 132a.

The coupling member 157 can then be rotated in 30 a direction 169 such the interior set of threads 165 carried thereon engages the exterior set of threads 153.

As a result, the two coupling members 126a and 157 are

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lockingly engaged together with the insertion member 165 extending through the opening 134a in the septum 132a.

35 Hence, fluids can flow from the container 150a via the connector system 1264 and 157 through the tubing member 159 to the recipient.

Injection sites of the type described above ~-1-e -21are also usable in connection with other fluid flow coupling components. For example, with respect to Figure 14, a pre-slit injection site 160 of the type described above can be used in combination with a spike connector 162 of a conventional variety. Spike connectors such as the spike connector 162 can be used to pierce conventional ports such as the port 106 of the container 104 '(Figure When the spike connector 162 is so used, the pre-slit injection site 160 can then be utilized for the purpose of coupling to other fluid administration sets.

The injection site 160 illustrates an alternate form of swaging the first end 42c for the purpose of retaining the septum 52c therein. The first end 42c can be swaged so as to form an annularly shaped, spiral, spring-like member 164. The member 164 has a free end 164a which engages the exterior dome-shaped peripheral surface 54c of the septum 52c. The spiral, spring-like .swaged member 164 will tend to uncoil, thereby continuously applying axial force to the septum 52c and maintaining the domed exterior peripheral S, surface 54c.

S.Iii yet another alternate, Figure illustrates a pre-slit injection site 166 formed in a Y- S 25 junction member 168. The Y-junction member 168 is fixedly attached to first and second tubing members 170 and 172 respectively.

As an alternate to forming the slit 66d completely th- ough the septum 52d, as illustrated in 30 Figure 16, a, sl i 66e can be formed only partly through *I the septum 52e. Such a structure has the further advantage that, until used for the first time, the s" septum 52e is completely sealed.

The septum 52e can be formed in two parts.

One part can have a slit, such as the slit 66e, extending entirely therethrough. A second part can be formed without a slit. These two parts can be located adjacent one another in the first end 42e of the .Vts e ~u -22injection site.

The slit 66e may be longer on the top of the septun than the bottom. this feature aids blunt cannula alignment with the slit upon insertion, and aids resealability by minimizing the critical slit sealing interface area.

The slit could have a length with a range on the order of .03 inches (.0762 centimeters) to .150 inches (.381 centimeters). Preferably, a slit length on the order of .07 inches (.1778 centimeters) will be used in Scombination with a blunt cannula having a diameter on the order of .1 inches (.254 centimeters).

When initially used, the blunt cannula piercing member, such as the member 98, will be forced through the slit 66a, The lower peripheral surface 56e will then be punctured, providing access for the blunt cannula piercing member 98 into the fluid flow pathway 68e.

Pre-slit injection sites of the type described above can be utilized in combination with burette solution administration sets. One such set* 176 is illustrated in Figure 17. The set 176 includes a preslit .injection site 178 of the type described above.

25 The injection site 178 is affixed to an exterior planar surface 180 of the burette 182. A removable cover 184 can be used to maintain the injection site 178 in an aseptic condition until blunt cannula 186 or 188 is inserted therethrough.

30 Figures 19 thrcugh 23 disclose a method of making a pre-slit injection site.

In a first step, a housing 200 is provided. The housing 200 has an interior tapered surface 202 at a first end 202a thereof. The interior peripheral surface terminates in an annular channel 204.

A cylindrical septum 206 can be provided adjacent the end 200a.

In a second step, the septu= 206 can be forced X~ C -23into the end 202a of the housing 200 and slightly deformed by the tapered peripheral surface 202 using an axially moving die 210. When positioned by the die 210, the septum 206 is located adjacent an internal annular right 212 which bounds the annular channel 204.

In a third step, a second die 214 can be utilized to swage the end 200a into spiral-shaped, spring-like members 200b which apply axially directed forces against an exterior peripheral surface 206a of the septum 206. The axially dizs.cted forces form the flat surface 206a into a domed exterior peripheral surface 206b as illustrated in Figure 23.

Simultaneously, with swaging the end members 200a so as to lock the septum 206 into the housing 200 and to form the domed exterior peripheral surface 206b, a knife 216 can be utilized tQ form a slit in the septum 206. Alternatively, the slit may be cut by a separate die in a separate step. If the septum 206 is formed as an extrusion, the slit can be created during the extrusion process. If the septum 206 is formed by stamping from a rubber sheet, the slit can be cut during the stamping process. If the septum 206 is formed by compression molding, the slit can be cut during the trimming process.

25 In order to extrude the slit into rod, a flat foe pin extrusion bushing can be used. A trailing ribbon may be attached to the bushing. The ribbon would prevent curing material across the slit. The ribbon or wire could be placed in the rod core and later stripped 30 out leaving a slit. An inert substance, such as silicone oil, could be coextruded in the center of the rod to prevent curing across the slit and provide lubrication and a visible target for cannula insertion.

Figures 24 and 25 illustrate alternate swaging steps wherein a die 220 moving axially toward the housing 200 swages the end region 200a so as to form an annular U-shaped region 200c and the exterior domed S peripheral surface 206c.

iN i h /S Y -24- The dies 214 or 220 can be formed with various alternate sha-oed swaging surfaces 224, as illustrated L, Fig-ure 2?6, depending on the precise shape- of the evid swage wh r I is desired. It will be understood that all such vatic -i.'ons in the swaging operation are within the spirit and cope of the present invention.

The injection site configuration need riot be limited 'to the configurations depicted in Figures 3 through SB, 9, and 12 through 16. Rather, several configurations could be constructed, Any such configuration~ would provide a, flexible pre-slit sealing member captured in a chousing which provides comression to create a seal against pressure and a void region to accommodate deformed portions of: the sealing member material only when the material is deformed or dispolaco~d by a blunt cannula piercing member. one such possible Configuration is depicted in Fi-,ures 27 and 28, Tiqures 29 and 30 illustrate a tapered cannula structure 250 which is an alternate to the tanered cannula 98. The cannula 250 includes a proximal end 252 with an interior region 254. The region 254 is in part bovzded by an internal peripheral wall 256 which is formed with a standard Luer taner. The tanered cannula 25 250 can be formed with a Luer-type coupling flange 257 at the proximal end so as to be releasably connectable.

to *the syringe 82 as was the tapered cannula 98 previously discu.-ed.

Etending from the proximal end 252 is a 30 cylindrical tube having a cylindrical =id.-!:eqion 258 and a distal end member 260. Tha member 260 has a generally elongated, cylindrical shape with an exterior side wall 262. A centrally located, cylindrical, internal fluid flowt path 264 extends through -the distal end =e~bar 260 and mid-region 258 in flu~id flow comunication with -the interior region 254.

The distal end of the end member 260 has a tered exter-or ZArf ace 2656. T"he tapered exterioft 4.

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surface 266 minimizes insertion force as the cannula 250 is being forced through a slit of a septun, such as the slit 66 in the septum 52. The angle of tamper of thj surface 266 is -areferably in a range bet-ween 1 to degrees.

The 'aemer 260 is also provided with a plurality of elongated grooves, 268. The g-rooves 268 in the e~cterior wall of the member '460 decrease the surface area of contact at the cannula/se-ptum interface during insertion of the cannula into the injection site 14.

This reduced exterior contact surface area clecreases the frictional component of the insertion force.

In one embodiment, the tapered bliant cannula 250 mk..y have overall insertion length, corresponding to combined axial lengths of iiid-region 258 and end member 260, on the order of 0. 375 inches 9525 centimeters) An alternate cannula structuire 280 is illustrated in Figures 31, 32 and 33. The cannula structure 280 includes a proximal end region 282 corresponding to the end region 252 of the cannula 250.

The region 282 includes a Luer flange 283. The cannula i: *280 also includes a ciantral, elongated, cylindrical region 288.

The 'entral region 288 carries at a distal end thereof an elongatad cylindrical end member 290. The See Tmember 290 includes an exterior, peripheral, cylindricalsurface 292 (Figuare 31). Thie surf?/,,.e 292 Ls interrupted Iby a plurality of spaced-apart, elongated slotq or apertures 294. The slots 294 a-&a defined by first and feet 30 second sipaced-apart, elonga\ parallel side. surfaces so". .:294a and 294b. Each of the slots ter~minates in an end surface 294c at the central region 288.

A fluid flow path 294d extends through the cannula 260. The flow path 294d is in" fluid flow communication with the s3D~294.

Between the slots 294, at a distal end of tChe region the exterior surfface 292 terminates in taiperad end regions 298 to f'acilitate inserti,,'on of the -26cannula into a pre-slit injection site. The slots 294 themselves also function to decrease the surface contact area, and this further minimizes the insertion force.

The slots 294 are oriented substantially degrees apart around a longitudinal axis 300. The slots 294 increase the internal flow path cross-section. This increases the fluid flow rate.

The slots 294 also provide for enhanced dispersion characteristics owing to the fluid flowing radially out through the slots 294. This radial flow, effecting as change in fluid flow 6irection of about degrees, promotes flushing and' dispersion of fluid through the injection site 34.

Another embodiment of a blunt cannula 310 is illustrated in Figures 34 through 37. The cannula 310 is formed with an enlarged proximal connection region 312 corresponding to the region 252 of the cannula 250.

The region 312 includes a Luer flange 313 and a central fluid flow region 314.

An intermediate, cylindrical region 318 extends from the proximal connection region 312. The cylindrical intermediate region 318 includes a fluid flow path 320 in communication with the fluid flow region 314.

0, S 25 The end region 31 extends from the region 318 and includes a first cylindrical portion. 326 into which the fluid flow path 320 extends. The region 326

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a teraainat.,s in a tapered exterior surface 328. The tapered exterior surface 328 merges with a centrally 30 located lead post or guide post 330. The lead post 330 terminates in a hemispherical end surface 332.

The lead post 330 helps locate the septum slit 66 prior to insertion and facilitates penetration of the septum slit 66 by the cnnila. The lead post 330 35 facilitates insertion by providing a very low insertion force at the beginning of the insertion step as the cannula is pushed through the slit, such as the slit 66.

In a preferred embodiment, the guide post 330 t -27can have a length on the order of 0.060 inches (.1524 centimeters) and a diameter on the order of 0.050 inches (.127 centimeters).

The end region 318 includes a novel structure for increasing the flow rate and enhancing dispersion characteristics. In particular, the region 318 includes three radially oriented slots 338. Each slot 338 has sides 339a and 339b which each lie along a radius of the cylindrical portion 326 as best illustrated in Figure 37. The fluid flowing through the cannula 310 undergoes a change in direction (of up to about 90 degrees relative to the cannula center line 337) in the slots 338. This change in direction increases fluid dispersion. Further, since the slots 338 open radially, fluid flow can be maintained even if the end surface 332 of the cannula is pushed up against any material in the system in which the cannula is inserted.

Another embodiment of the tapered cannula -is illustrated in Figures 38 through 40 and is designated generally therein by reference numerall 340. The cannula 340 includes a proximal end 342 which can include a Luer coupling flange 344 for cooperating with a suitable mating structure on a syringe. The proximal end 342 also 25 defines an interior region 346.

Extending from the proximal end 342 is a generally cylindrical mid-region 348. Extending from the mid-region 348 is an end member or region 350 which includes a tapered surface 352.

The distal and of the end region 352 terminates in a blunt, arcuate end surface 356. Defined within the mid-region 348 and end region 350 is an internal fluid flow channel 354 which communicates with the interior region $46. Fluid discharges from the flow channel 354 via grooves or apertures 358 in the end region 350. The change in direction of the fluid flow as the fluid passes from the interior channel 354 through the apertures 358 improves fluid dispersion with 4*4 e 00 9 r S.

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n'.a re r+ I:r, -28respect to mixing or flushing in the system downstream of the cannula the injection site, drug vial, etc.). The apertures 358 may also function to increase withdrawal force or tug resistance.

Horeover, since the fluid passes radially out through the apertures 358, fluid flow through the cannula 340 can be maintained even when the distal end surface 356 of the cannula is bottomed out or pushed against any material in the system in which the cannula is inserted.

The structure of the cannula 340 is adapted to be constructed .with a _inimal lead post length the portion of the cannula distal end between the end surface 356 and the interior flow channel 354) Further, the design accommodates the use of a minimal tip diameter, minimal taper angle, and minimal cannula diameter. The minimization of these parameters results in a decrease in the peak insertion force required to properly install the cannula in the injection site.

Preferably, the total cross-sectional flow area through the three apertures 358 is about, three times the cross-sectional flow area of the interior channel 354. This enhances the flow rate capability compared with a simple open ended cylindrical flow 25 channel of eaual length.

i The design of the cannula 340 a is effective in reducing or limiting "kick back" or r'ooil o the cannula after insertion. The resilient material of the septum in an injection site can subject the S 30 cannula to forces tending to push the cannula back out of the septum. The kick back forces on the cannula 340 are minim:ized by the provision of the generally cylindrical mid-region 348.

Another embodiment of the cannula is illustrated in Figures 41 and 42 wherein the cannula embodiment is designated generally therein by the reference numeral 360. The cannula 360 f includes a oroximal end 362 defining an interior region f 4 i i -29- 364 and having a Luer flange 366 for connection to a suitable mating engaging structure.

A generally cylindrical mid-region 366 extends from the proximal end 362, and an end region 368 extends from the mid-region '366. As with the previous embodiment of the cannula 340 illustra.ed in Figures 38 through 40, the embodiment of the cannula 360 minimizes kick back or recoil owing to the provision of a substantially cylindrical mid-region 366. This design also increases withdrawal or tug resistance.

A generally cylindrical internal flow channel 370 extends through the end region 368 and mid-region 366 in communication with the interior region 364 of the proximal end region 362. The end regi-on 368 is provided with a tapered surface 372. The design permits the use of a very small taper to minimize the insertion force.

Further, the design permits the cannula 360 to be constructed with a small tip diameter, small taper angle, and small cannula diameter so as to reduce the peak insertion force.

Another embodiment of the cannula is illustrated in Figures 43 through 44 and is -designated generally therein by reference numberal 380. The cannula 380 includes a proximal end S 25 382 with a Luer flange 384. An interior fluid flow region 386 is defined on the interior of the proximal end 382.

Extending from the proximal end 382 is a midregion 388. A distal end region 390 extends from the 30 mid-region 388. An internal fluid flow channel or path 392 extends through the end region 390 and mid-region 388, and is .in communication with the interior flow region 386.

SThe end region 390 has an- exterior tapered surface 394. This facilitates insertion of the cannula into the 'injection site. In contrast, the mid-region 388 is generally cylindrical so as to minimize kick back /T "A and increase the withdrawal force or tug resis .nce.

S\ Further, to provide even greater withdrawal force, the mid-region 388 includes an annular barb 396.

The barb 396 has a sufficient radius so as to preclude damage to the septum of the injection -site and so as to accommodate molding in a straight draw tool. The maximum diameter of the annular barb 396 may typically be on the order of 0.02 inches (.0508 centimeters) greater than the diameter of the cylindrical mid-region 388. Although the barb 396 functions to prevent inadvertent removal of the cannula 380 from the septum of the injection site, removal of the cannula 380 can still be achieved by entering a sufficiently great axially directed removal force on the cannula 380.

Still another embodiment is illustrated in Figure 45 which includes a blunt tapered cannula insertion member 400 for insertion into a pre-slit injection site, the cannula 400 having a distal end region 402 with a tapered exterior surface which in the preferred embodiment is an approximately 8 degrees taper. The defined aperture 404 for fluid flow is disposed at the end 406 of the distal end region 402.

The end 406 includes a radiused tip defined by a radius of approximately 0.01 inch (.025 centimeters). The radiused tip reduces insertion force, assists in 25 locating the slit in the injection site and in addition has the practical advantage of facilitating complete filling of the cannula mold cavity.

The tapered surface of the distal end region 402 has an axial length of approximately 0.10 inch in the preferred embodiment. Adjacent to the tapered distal end region is a generally cylindrical region 408 for entering into the injection site behind the distal end region 402, thereby reducing kick back during insertion. The generally cylindrical region 408 has a 35 small draft angle such as about one-half degree.

The force required to insert any of the abovediscussed embodiments of the blunt tapered cannula into the septum of the injection site depends upon a number factors: friction at the cannula/septum interface, cannula diameter, cannula taper angle, and degree o.

septum compression. The cannula/septum interface friction is, in turn, dependent upon lubrication, if any, material properties, arnd surface finish. It will be understood that the friction at the cannula/septum interface can be reduced by providing a smoother surface finish on the cannula by sand blasting the cannula exterior surface) or. by molding .the cannula so as to produce a matte finish. Conventional lubricants can also be used to further reduce the friction and thereby lower the insertion force required.

In the embodiments of the cannulae described herein, the mid-region and the tapered distal end region may be alternatively characterized as together forming at least one tube defining a fluid flow path therein with the tube having a distal end region for penetrating the injection site.

In preferred contemplated embodiments, the exterior surface of the distal end region may have a taper angle as small as between 1 and 15 degrees.

Further, a locking means, such as the locking arms 100a and 100b discussed..with reference to Figures and 5B, may be provided on the cannula embodiments 25 illustrated in Figures 29 through 44 to permit the cannulae to be releasably locked to the injection site.

The above described insertion members, usable as part oZ a blunt cannula, are preferably molded of a plastic formulation including silicone or other 30 lubricant. The use of silicone or other lubricant increases the 'ease of insertion of that member into the pre-slit injection site.

From the foregoing, it will be observed that numerous variations and modifications may be effected 35 without departing from the spirit and scope of the novel concept of the invention. It is to be understood that no limitation with. respect to the specific apparatus illustrated herein is intended or should be inferred.

Claims (16)

1. A blunt cannula insertiont member adapted to be inserted into a pre-slit injection site, said insertion member comprising: at least one tube defining a fluid flow path therein, said tube having a distal end region for penetrating said injection site; said tube having an aperture In an exterior surface in said distal end region through which fluid can flow to or from said fluid flow oath; and said tube including means for reducing the insertion force, said means including longitudinally oriented grooves In the exterior surface of said tube and a tapered surface on a least part of said distal end region, the taper terminating at a position which is not distal, of said aperture.

2. An insertion member as claimed in claim 1 In which said tube is cylindrical and in which said grooves are positioned at 90 degree increments around the periphery of said tube.

3. An insertion member as claimed In claim 1 in which said tapered surface terminates at the distal end of said tube.

4. An insertion member as claimed in claim 1 in which said aperture is a circular opening at the distal. end of said tube.

5. An insertion member as claimed in claim 1 in which each said groove includes an arcuate bottom surface. 61 A blunt cannula insertion member adapted to be inserted into a pre-slit injection site, said insertion member comprising: at least one tube defining a fluid flow path therein, said tube having a distal end region for penetrating said. injection site; said tube having at least one aperture i* S S S." S* tS S S S .5 S. S. S S S S 21 1. -33- 0. 4.0. in an external surface In said distal end region through which fluid can flow to or from said fluid flow path; and said distal end region Including a tapered exterior surface to facilitate insertion, the taper terminating at a position which is not distal of said aperture, said tube also including a generally cylindrical region extending from said tapered distal end region for entering into said injection site behind said distal end region and reducing kick back during insertion.

7. An insertion member as claimed in claim 6 In which said tapered distal end region has a length of approximately one- half the length of said generally cylin~drical region.

8. An insertion member as claimed in claim 6 in which said insertion member Includes an annular barb on the exterior jurface of said tube at the junction of said cylindrical region and said tapered distal end region to increase tug resistance.

9. An insertion member as claimed in claim 6 In which said insertion member Includes locking means for removably locking said member to said injection site. An Insertion member as claimed in claim 9 in which said locking means Includes an elongate deflectable aria that is engageable with said Injection site. 1i. A blunt cannula insertion member adapted to be inserted ii a pre-slit resealable injection site, said insertion mesmber comprising: a tube having a central bore throughout sa.1d tube, defining a fluid flow path thereln, said tube having a dL 'al end region for penetrqtIng said injection -34- *0 et 00 9 .0 *s S 0 S 0* .0 o 5 *00* S .0 Of S site; said distal end region defining at least one aperture in the distal end of sad distal end region through which fluid can flow to or froit said fluid flow path; said distal eid region including a tapered exterior surface to facilitate insertion; said distal end further including a radiused tip adjacent said tapered surface, said radiused tip reducing the insertion force into and assisting in locating the slit of said injection site, upon contacting the injection site with said cannula.

12. A blunt cannula insertion member adapted to be inserted into a pre-slit resealable injection site, said insertion member comprising: a tube having a central bore throughout said tube defining a fluid flow path therein, said tube having a distal end region terminating in a blunt radiused tip for penetrating said injection site; said distal end region defining Pt least one apertare in the distal end of said distal end region through which fluid can flow to or from said fluid flow path; said distal end region including a tapered surface; and said tube also including a generally cylindrical region extending from said distal end region for entering into said njection site behind said distal end region.

13. A cannula and injection site in combination comprising: a resealable injection site having a housing defining a fluid flow path therein and having a pre-slit sealing means for sealing said housing; a blunt cannula having a tube with a central bore throughout said tube, defining a fluid flow path therein, said tube extending through said sealing means to a .*o a a oooo S*e o a.. ooo Se a a a...I establ.ish a sealed fluid flow connection with said injection site, said tube having a distal end region extending beyond said injection site with a tapered surface and a blunt radiused tip; said tube having a generally cylindrical region merging with said tapered distal end region, said cylindrical region being received within said sealing means to provide reduced kick back and increased tug resistance; and said sealing means sealing the injection site upon removal of the cannula from the sealing means.

14. A cannula and injection site in combination comprising: an injection site having a housing defining a fluid flow path therein and having a pre-slit resealable sealing means for sealing said housing; a blunt cannula having a tube with a central bore throughout said tube, defining a fluid flow path therein, said tube extending through said sealing means to establish a sealed fluid flow connection with said sealing means to establish a sealed fluid flow connection with said injection site, said tube having a distal end region extending beyond said injection site and having a tapered surface on said distal end region; said tube having a generally cylindrical region merging with said tapered distal end region, said cylindrical region being received within said sealing means; and the sealing means and cannula cooperating to allow the sealing means to seal the injection site upon removal of the cannula from the injection site. A blunt cannula insertion member for being inr'rted into a pre-slit injection site, said insertion member comprisingi -36- at least one tube defining a fluid flow path therein, said tube having a distal end region with a taper for penetrating said injection site; and said tube defining in said distal end region a plurality of elongate slots oriented parallel to said fluid flow path, each slot extending from said flow path to the exterior of said tube thereby decreasing the exterior surface area of said tube and accommodating a lateral discharge of fluid from said tube..

16. An insertion member as in claim 15 in wh 4 .ch said tube distal end region includes a tapered exterior surface with a Os taper angle of between 5 and 30 degrees.

17. An insertion member as In claim 15 in which said .06 Insertion member includes a lead post on the distal end of said tube for defining an end of said fluid flow path along the longitudinal axis of said tube and, for functioning as a guide during insertion of said Insertion -member Into said injection site.

18. An insertion memrber as in claim 17 In which said lead post has a hemispherical exterior end surface.

19. An insertion member as in claim 17 in which said tube Is generally cylindrical and In which said lead post Includes a cylindrical portion with a diameter less than the diameter of said tube. An Insertion member as in claim 15 In which the sum of the longitudinal cross-sectlonal flow areas of said slots Is at least equal to the axial cross-sectional flow area of said ~>tube flow path.

37- S S S. S S. 55 S S S S 555* S S Se *5 S S S 5555 5**5 S. eS S 4e* S *5*555 S FI4~ >~Vr c~ 21. An insertion member as in claim 15 in which an end of each slot is angled in a direction outwardly and away from said distal end region. 22. An insertion member as In claim 15 in which each said slot is defined by two radially oriented side surfaces extending through said tube and diverging in the radially outward direction. 23. An insertion member as in claim 16 in which each said slot is defined by two spaced-apart, parallel, side surfaces extending through said tube. 24. An Insertion member? as in claim 15 In which three of said !rlots are equally spaced around said flow path. An insertion muember as In claim 15 in which four of said slots are equally spaced arouwid said flow path. 26. A blunt cannula Insertion member A:Oz being Inserted into a pre-sl~it injection site, said insertion member comprising: at least one tube defining a tfluid flow path therein, said tube having a distal end region for penetrating said Injection site; said tube defining eat least one aperture in said distal end region through which fluld can flow to or from said fluid flow path., and sald distal end region itclud~ng 4 tapered anterior surface to facilitate Insertion, said insertion member further including an annular barb on the exterior surface of said tube to increase tug resistance. 27. An Insertion member as In claim 15 In which said -38- insertion member includes 1 sking means for removably locking said member to said injection site. 28. An insertion member as in claim 27 in which said locking mweans includes an elongate, deflectable arm that is engageable with said injection site. 29. An insertion member as in claim 26 in which said insertion member includes locking means for removably locking said member to said injection site. 30. An insertion member as in claim 29 in which said S: locking means includes an elongate, deflectable Arm that is ir •engageable with said injection site. o" 31. An insertion member as in claim 17, or claim 18 with at C least said lead post including an insertion easing lubricant, 32. An insertion member as in claim 31 with said lubricant *oo including silicone incorporated into said lead post. C.o C k 33. A cannula lnert on member as in claim 15 including an ooCC e0; insertion easinC lubricant, C.. o 0 DATED this 1lth day of March, 1994. BAXTER INTERNATIONAL INC. By their Patent Attorneys PETER MAXWELL ASSOCIATES ABSTRACT A cannuj.a (340), usable w~t~ inj4~ction site~ includes a tube having a tapered distal end z~gion (352) and elongated discharge groove (358) for reducing the force needed to ins&~'t the cannui.a into the injection site. 0* ~I S S .5 S. S lbs lb S S l~ S Ii. t~ ~S S S *S S. *9 S. 5e S it.. .44 Se S N S. 55 ib 9 9 S. 4> 9 4..