MANIFOLD WITH ONE-WAY NEEDLELESS INJECTION SITE
Field of the Invention
The present invention relates generally to the medical arts, and more particularly to an intravenous infusion assembly including a manifold having a plurality of one-way needleless injection sites.
Background of the Invention Numerous medical procedures require intravenous infusion of various fluids or medicaments into a blood vessel of a patient (e.g., a vein or artery). Such infusion is typically accomplished by the insertion of a hollow introducer needle into a target blood vessel . The introducer needle is fluidly connected to one end of an elongate, flexible tube or fluid line, the opposite end of which is fluidly connected to a solution bag. The solution bag itself is typically suspended above the patient so as to allow gravity to facilitate the flow of fluid downwardly through the fluid line and into the patient's blood vessel via the introducer needle which remains operatively positioned therewithin. The fluid tube and solution bag are connected to each other via a metering apparatus which controls the infusion rate of fluid from the bag into the tube.
In many intravenous infusion assemblies, an injection site is fluidly coupled within the tubing intermediate the introducer needle and the solution bag. The injection site may be a Y-shaped configuration and comprises a tubular main body portion having a tubular side arm portion in fluid communication therewith. The distal end of the side arm portion is fluidly connected to the solution bag via an upper segment of the tubing, with the bottom end of the main body portion being fluidly connected to the introducer needle via a lower segment of the tubing. The top end of the main body portion is itself covered by a diaphragm which is
typically fabricated from rubber or a similar resilient material .
As will be recognized, the incorporation of the injection site within the tubing allows various medications to be intravenously administered to the patient through the existing infusion site within the blood vessel, thus eliminating the need to subject the patient to additional needle sticks. Certain medical procedures require ongoing therapy, and in addition to, or in place of, a Y-shaped configuration injection site, a multiport injection site manifold may be mated with the intravenous tubing. The inclusion of manifold injection site within the tubing allows various medications to be selectively infused into the blood vessel of the patient by the adding fluids to the solution flowing in the intravenous tubing from the solution bag, through an upper tubing segment, through the manifold through a lower tubing segment and finally into a blood vessel .
A multiport manifold may typically comprise an elongate flow tube which defines an interior fluid passage, wherein the flow tube has a distal and proximal end connectable between first and second segments of tubing to facilitate the passage of fluid between said segments of tubing and through the interior flow passage. Said manifold elongate flow tube may include two or more injection sites which are fluidly coupled to said interior flow passage allowing multiple introducer needles to be utilized simultaneously or as required by the treatment. As with a Y-shaped injection site, the incorporation of multiple ports within the manifold allows various medications to be intravenously administered to the patient through the existing infusion site within the blood vessel, thus eliminating the need to subject the patient to additional needle sticks, but while providing additional ports of access than allowed by a Y-shaped injection site. This supplemental infusion is typically accomplished through the
utilization of a conventional syringe, the needle of which pierces and is extended through a diaphragm disposed on the top end of the main body portion of the injection site. Subsequent to the expulsion of a medication from within the syringe and into the flowing solution, the needle is retracted out of the main body portion of the injection site, with an aperture created in the diaphragm due to the passage of the needle therethrough being substantially closed upon such retraction due to the resiliency of the diaphragm.
Though providing certain benefits to the patient, the injection sites constructed in accordance with the prior art possess certain deficiencies which detract from their overall utility. As previously explained, the use of such injection sites typically requires that the needle of the conventional syringe be extended through
(i.e., puncture) a diaphragm attached to the top end of the main body portion of the injection site. However, the necessity of having to utilize a syringe with a needle to facilitate the introduction of the medication into the solution flow is undesirable due to the risk of inadvertent needle sticks. In recognition of this deficiency, there has also been developed in the prior art needleless injection sites which incorporate a diaphragm adapted to assume open and close configurations without having a needle inserted thereunto. Though these needleless injection sites eliminate the necessity of having to puncture the diaphragm with a needle, they also possess certain deficiencies which detract from their overall utility. Foremost of these deficiencies is the difficulty associated with disinfecting the injection site, and in particular the diaphragm thereof, subsequent to medication being infused thereunto. In this respect, after each use of the injection site the diaphragm must be cleaned, with such cleaning typically being accomplished through the application of alcohol or a similar disinfecting agent thereto. However, due to the
configuration of the diaphragm, complete and effective disinfection thereof is often difficult to achieve, thus increasing the risk of the inadvertent introduction of contaminants into the solution stream upon subsequent use of the injection site.
Summary of the Invention
In accordance with the preferred embodiment of the present invention, an intravenous multiport manifold device comprises an elongate flow tube which includes an interior fluid passage. The elongate flow tube has a distal and proximal end which are connectable between first and second segments of an intravenous tube line. The flow tube facilitates the passage of fluid between the first and second tubing segments through the interior fluid passage. The elongate flow tube includes at least two fluid ports, each said ports defining a port passage from the exterior of the flow tube to the flow tube interior fluid passage. A needleless injection site having unidirectional flow is coupled to one or more of said fluid ports to facilitate the infusion of a liquid from an introducer syringe into the interior fluid passage through said port passage. The remaining fluid ports may be coupled to needleless injection sites having bi-directional flow or to other means of transporting fluid to or from the patient such as an I.V. set or I.V. line.
The present invention facilitates the use of multiple introducers which may be required in ongoing therapy of a patient. The needleless injection site manifold configuration of the present invention is a significant advancement in the art as it eliminates the need for check valves or stop cock valves which are costly to manufacture. Further, the needleless injection site of the manifold decreases the possibility that backflow of contaminants could be introduced to an introducer syringe .
Each of the needleless injection sites associated with the manifold of the present invention comprises a housing defining an interior chamber. A central opening in the top of the injection site communicates with the interior chamber. A reseal member disposed within the central opening in the interior chamber has an elastically openable and closable aperture. One of the reseal member readily resides in the first position within the housing while the aperture is in a closed configuration.
The reseal member is deformable such that the application of distally directed pressure onto the reseal member will cause the reseal member to distally advance within the housing to a second position when the aperture assumes an open configuration and communicates with the fluid passage . The removal of the directed pressure therefrom will cause the reseal member to resiliently turn into the first position wherein the apertures assumes the closed configuration. It should be noted and understood that with respect to the embodiments of the present invention, the materials suggested may be modified or substituted to achieve the general overall resultant high efficiency. The substitution of materials or dimensions remain within the spirit and scope of the present invention.
Brief Description of the Drawings
These, as well as other features of the present invention, will become more apparent upon reference to the drawings wherein:
Figure 1 is a perspective view illustrating a prior art tri-port manifold for use in intravenous applications.
Figure 2 is a perspective view of a tri-port manifold with a one-way needleless injection site constructed in accordance with the present invention;
Figure 3 is a cross-sectional view of one of the manifold needleless injection sites shown in Figure 2, illustrating the reseal member thereof in a first, closed position; Figure 4 is an exploded view illustrating the components comprising the reseal member shown in Figures 3 and 5 ; and
Figure 5 is a cross-sectional view of the reseal member shown in Figure 3, illustrating the reseal member thereof as deformed into a second, open position.
Detailed Description of the Preferred Embodiments
The detailed description as set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiments of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the functions and sequences of steps for constructing and operating the invention in connection with the illustrated embodiments. It is understood, however, that the same or equivalent functions and sequences may be accomplished by different embodiments and that they are also intended to be encompassed within the scope of this invention. Referring now to the drawings wherein the showings are for purposes of illustrating preferred embodiments of the present invention only, and not for purposes of limiting the same. Figure 1 shows a prior art tri-port manifold 10 for use in intravenous applications. The prior art tri-port manifold 10 comprises an elongate flow tube 12 having a distal end 14 and a proximal end 16. The prior art tri-fold manifold 10 is connectable between a first segment of intravenous tubing (not shown) and a second segment of intravenous tubing (not shown) . The elongate flow tube 12 defines an interior lumen 18.
Fluid travels from the first segment of the intravenous tubing which is connected to the distal end
14, travels through the interior lumen 18 to the second segment of intravenous tubing which is connectable to the proximal end 16. The elongate flow tube 12 has fluid ports 20, 22 and 24. Each fluid port 20, 22 and 24 is defined an aperture 26 creating a fluid passage to the interior lumen 18 of the elongate flow tube 12. The engagement aperture 26 allows for the passage of fluid from an introducer 28 (shown in phantom) .
Each fluid port 20, 22 and 24 include Luer lock threading 34 and Luer lock fittings 36 (shown in phantom), 38 and 40. The introducers 28, 30 and 32 are syringes with a plunger design. The introducer is engaged to the Luer lock fittings 36, 38 and 40 to introduce fluid within the introducer 28, 30 and 32 through the fluid ports 20, 22 and 24 and into the interior lumen 18.
Each fluid port 20, 22 and 24 includes an aperture 26 for fluid passage which may be opened or closed by stop-cock valves 42, 44 and 46. Each stop-cock valve is manually operable to an opened and closed position from a handle tab 48, 50 and 52. Stop-cock valves 42 and 46 are shown in the closed position due to the location of the handle tabs 48 and 52. The stop-cock valve 44 is shown in an open position with the handle tab 50 in a parallel relation to the elongate flow tube 12.
The stop-cock valves 42, 44 and 46 are necessary in the prior art configuration to allow a passage to be opened to the interior lumen 18 during infusion of medicine or other fluid, and requires closure subsequent to infusion of contamination or spillage. The prior art manifold 10 includes a support platform 54. The prior art manifold 10 is difficult to operate as it requires constant manipulation, and creates a possibility of error if a check valve is not properly closed or opened during treatment. Further, the prior art device is costly produce as it includes multiple moving parts, fine tolerances and difficult alignments.
Referring specifically to Figure 2, there is shown a tri-port manifold 56 of the preferred embodiment of the present invention. The tri-port manifold 56 comprises a flow tube 58 having a proximal end 60 and a distal end 62. The distal end 62 is engageable with the first segment of intravenous tubing (not shown) and the distal end 62 is engageable with a second segment of intravenous tubing (not shown) .
The flow tube 58 defines and interior lumen 64 which allows the transport of fluid from a first segment of intravenous tubing connected to the distal end 62, the second segment of intravenous tubing attached to the proximal end 60. The flow tube 58 is rigidly attached to a support platform 66. The support platform is preferably formed of a rigid plastic material and may be suitable for engagement with a clamp, clip or vice to connect the manifold to the patient's bed or other medical equipment in close proximity to the patient during treatment. The flow tube 58 is preferably formed of a rigid plastic material, but it is additionally contemplated that the same may be formed of other rigid or suitable material.
The flow tube 58 includes needleless injection site 68, 70 and 72. The needleless injection sites 68, 70 and 72 are coupled to the flow tube 58 and each include interior fluid passages in fluid communication with the interior lumen 64. Each needleless injection site 68, 70 and 72 includes Luer threading 74. Luer lock fittings 76 and 78 are attached to each needleless injection site 68, 70 and 72. In this regard, a needleless introducer 80 (shown in phantom) , intravenous line 82 and needleless introducer 84 infuse fluid through an engagement aperture 86 to introduce fluid into the interior lumen 64 of the flow tube 58. A typical needleless syringe is shown as an introducer 84 which has a syringe housing 88 and a plunger 90. The manual tab 92 of the plunger 90 is depresses by an operator and the tip 94 of the introducer
84 engages with the Luer lock fitting 78 and infuses fluid through an interior passage (as shown in Figure 3) located within the needleless injection site housing 96 and lower housing coupling 98. The intravenous line 82 may be in fluid communication with an I.V. set or other similar fluid containment system that allows liquid to flow into the interior lumen 64 of the flow tube 58 by a pump or gravity.
Referring now to Figures 3-5, the injection site 110 of the present invention comprises a hollow housing 116. The housing 116 itself comprises an upper section 118 which defines a reduced diameter proximal portion 120 having Luer threads 122 formed on the outer surface thereof. In addition to the upper section 118, the housing 116 includes a lower section 124 which is rigidly attached to the upper section 118. When attached to each other, the upper and lower sections 118, 124 collectively define an interior chamber 126. In this respect, the proximal portion 120 of the upper section 118 defines a central opening 128 which communicates with the interior chamber 126. The transition between the central opening 128 and interior chamber 126 is defined by an annular, inclined shoulder 130 formed within the inner surface of the upper section 118. The lower section 124 of the housing 116 includes a central portion 132 defining a generally planar, circularly configured proximal surface 134 which is circumvented by an annular flange portion 136. Formed within the outer surface of the central portion 132 and extending thereabout is a continuous, annular shoulder 138. When the upper and lower sections 118, 124 are attached to each other, the distal rim of the upper section 118 is abutted against the shoulder 138, with the flange portion 136 extending along the inner surface of the upper section 118 in direct contact therewith. The attachment of the upper and lower sections 118, 124 to each other is preferably facilitated by a sonic weld
between the distal rim of the upper section 118 and the shoulder 138 defined by the lower section 124. However, it will be recognized by those of ordinary skill in the art that alternative attachment methods, such as the use of adhesives, may be employed in the injection site 110. The upper and lower sections 118, 124 are sized such that when rigidly attached to each other in the aforementioned manner, the outer surface of the upper section 118 is substantially flush with the outer surface of the central portion 132 of the lower section 124.
Extending proxi ally from the proximal surface 134 of the central portion 132 in substantially perpendicular relation thereto is an elongate dilator projection portion 140 which is coaxially aligned with the central opening 128 of the upper section 118. The dilator projection portion 140 has a generally cylindrical configuration, and defines a blunt proximal tip 142. In addition to the dilator projection portion 140, formed on the lower section 124 and extending distally from central portion 132 is fluid connection 146. Fluid connection 146 fluidly communicates the dilator projection portion 140 with the interior lumen 148 of the elongate flow tube 150 of the manifold 110 of the present invention. The lower portion 124 is coupled to the flow tube 150 at a coupling wall 152 which engages flow tube 150. The dilator projection portion 140 is rigidly connected to the flow tube 150. Further, the flange portion 136 is rigidly attached with the flow tube 150 in connection 154. Thus, the fluid connection 146 with the interior lumen 148 create an elongate fluid passage 156 from the interior lumen 148 that is coaxially aligned with the central opening 128 of the upper section 118.
The injection site 110 constructed in accordance with the present invention further comprises a reseal member 158 which is disposed within the central opening 128 and interior chamber 126 of the housing 116. The reseal member 158 comprises a resilient body 160 having
a generally cylindrical proximal portion 162 which defines a proximal end 164, and a generally cylindrical distal portion 166 which defines a distal end 168. Disposed between the proximal and distal portions 162, 166 is a cylindrically configured middle portion 170. The proximal, middle and distal portions 162, 170, 166 are of progressively increasing diameter, with the diameter of the distal portion 166 exceeding that of the middle portion 170, and the diameter of the middle portion 170 exceeding that of the proximal portion 172. The transition between the proximal and middle portions 162, 170 is defined by a first beveled shoulder 172, with the transition between the middle and distal portions 170, 166 being defined by a second beveled shoulder 174. The proximal end 164 of the body 160 defines a recessed, circularly configured outer surface 176 which has a generally planar configuration. In addition to the outer surface 176, the proximal end 164 defines a generally semi-spherical inner surface 178. Extending axially through the proximal end 164 from the outer surface 176 to the apex of the inner surface 178 is an aperture 180. Additionally, formed about and extending radially inward from the distal end 168 of the body 160 is a continuous annular flange 182, the inner peripheral edge of which defines an enlarged bead. The body 160 is preferably fabricated from silicone, though the same may alternatively be fabricated from a similar resilient material such as rubber.
The reseal member further comprises a radial leaf spring 184 which is disposed within the body 160. The radial leaf spring 184 comprises a generally cylindrical base portion 186 which transitions into three (3) identically configured, equidistantly spaced leaf portions 188 via a beveled shoulder 190. The leaf portions 188 are separated from each other by three (3) longitudinally extending slots 192 which extend to the shoulder 190. Formed on the inner surfaces of respective
ones of the leaf portions 188 are generally wedge-shaped ramps 194, the use of which will be discussed in more detail below.
The radial leaf spring 184 is disposed within the body 160 in a manner wherein the outermost ends of the leaf portions 188 are received into an annular channel circumventing the semi-spherical inner surface 178 of the proximal end 164. Additionally, the distal portion 166 of the body 160 is wrapped about the base portion 186 of the radial leaf spring 184 such that the flange 182 extends about the inner surface thereof . The radial leaf spring 184 is preferably fabricated from polysulfone or polycarbonate, though similar rigid materials with memory may be utilized as an alternative. In addition to the body 160 and radial leaf spring 184, the reseal member 158 of the injection site 110 comprises an elongate, generally cylindrical axial donut spring 196 which has a splined outer surface and includes a bore 198 extending longitudinally (i.e., axially) therethrough. As will be discussed in more detail below, the donut spring 196 defines a first or proximal end which is normally abutted against the distal end 168 of the body 160, and a second or distal end which is normally abutted against the housing 116, and in particular the proximal surface 134 of the central portion 132 of the lower section 124. Like the body 160, the donut spring 196 is preferably fabricated from silicone, though the same may alternatively be fabricated from a similar resilient material such as rubber. In the injection site 110, the aperture 180 extending through the proximal end 164 of the body 160 is elastically openable and closable. In this respect, the reseal member 158 of the injection site 110 normally resides in a first position" within the housing 116 (shown in Figure 3) wherein the aperture 180 in a closed configuration. Importantly, the reseal member 158 is selectively deformable such that the application of
distally directed pressure thereto, and in particular the raised lip circumventing the outer surface 176 of the proximal end 164, will cause the same to distally advance within the housing 116 to a second position (shown in Figure 5) wherein the aperture 180 assumes an open configuration. As will be discussed in more detail below, due to the resiliency of the reseal member 158, and in particular the donut spring 196 thereof, the removal of the distally directed pressure from the proximal end 164 will cause the reseal member 158 to resiliently return to its first position wherein the aperture 180 reassumes the closed configuration.
When the reseal member 158 is disposed in its normal, first position within the housing 116, the dilator projection portion 140 of the lower section 124 is extended through the bore 198 of the donut spring 196 and into the hollow interior of the radial leaf spring 184. In this respect, the proximal tip 142 of the dilator projection portion 140 extends to approximately the beveled shoulder 190 of the radial leaf spring 184. When extended into the radial leaf spring 184, the dilator projection portion 140 passes through the opening defined by the annular flange 182 of the body 160, and in particular the bead defined thereby. Importantly, the diameter of the opening defined by this bead is less than the outer diameter of the dilator projection portion 140. As such, when the dilator projection portion 140 passes through this opening, the bead is sealed in a fluid-tight manner against the outer surface thereof, i.e., the bead is compressed between the outer surface of the dilator projection portion 140 and the inner surface of the base portion 186 of the radial leaf spring 184.
Additionally, when the reseal member 158 is in its first position, both the proximal and middle portions 162, 170 of the body 160 reside within the central opening 128 of the upper section 118, with the second beveled shoulder 174 and distal portion 166 of the body
160, as well as the donut spring 196, residing within the interior chamber 126 of the housing 116. Importantly, though the diameter of the middle portion 170 of the body 160 exceeds the diameter of the proximal portion 162 thereof, both the proximal and middle portions 162, 170 extend along and cover the outer surfaces of the leaf portions 88 when the reseal member 158 is in its first position. In this respect, due to the middle portion 70 being disposed within the central opening 128, the same is collapsed (i.e., compressed) against the outer surfaces of the leaf portions 188, thereby "flattening" the first beveled shoulder 172 normally defined between the proximal and middle portions 162, 170. When the reseal member 158 is in its first position, the second beveled shoulder 174 of the body 164 extends along and covers the shoulder 190 of the radial leaf spring 184, and is compressed between the shoulder 190 and the inclined shoulder 130 formed in the inner surface of the upper section 118. Additionally, the proximal end 164 of the body 160 protrudes slightly beyond the rim of the proximal portion 120 of the upper section 118.
As previously indicated, the proximal end of the donut spring 196 is abutted against the distal end 168 of the body 160, with the distal end of the donut spring 196 being abutted against the central portion 132 of the lower section 124, and in particular the proximal surface 134 thereof. Importantly, in the injection site 110, the distance separating the shoulder 130 from the proximal surface 134 of the central portion 132 slightly exceeds the combined length of the distal portion 166 of the body
160 and donut spring 196. Thus, when the reseal member 158 is disposed in its first position within the housing 116, the donut spring 196 is slightly compressed between the distal end 168 of the body 160 and the proximal surface 134 of the central portion 132, thus applying a pre-load thereto which causes the same to bulge slightly outwardly as shown in Figure 5. Due to the application
of the pre-load thereto, the donut spring 196 is operable to force the middle portion 170 of the body 160 upwardly into the central opening 128, thus collapsing the same in the aforementioned manner and facilitating the compression of the second beveled shoulder 174 between the shoulders 130, 190. Importantly, when the reseal member 158 is in its first position, the leaf portions 188 of the radial leaf spring 184 apply a radially inward biasing force to the proximal end 164 of the body 160 which maintains the aperture 180 in its closed configuration.
As seen in Figure 5, the application of distally directed pressure to the proximal end 164 of the body 160 by an infusion component such as the tip 200 of the introducer 198 causes the radial leaf spring 184 to be distally advanced over the dilator projection portion 140. Such advancement removes the second beveled shoulder 174 of the body 160 from its abutting contact with the shoulder 130, and further forces the middle portion 170 of the body 160 from within the central opening 128. Additionally, such distal advancement facilitates the compression of the donut spring 196, thus causing the same to bulge outwardly within the interior chamber 126 of the housing 116. Importantly, the camming action of the dilator projection portion 140 against the leaf portions 188, and in particular the ramps 194 formed on the inner surfaces thereof, causes the same to be flexed outwardly, thus facilitating the radial expansion of the aperture 180 to its open configuration. Additionally, since the middle portion 170 of the body 160 is removed from within the constricting central opening 128 of the upper section 118, the same resiliently returns to its normal orientation (shown in Figure 3) , thereby forming the first beveled shoulder 172 and defining an expandable and collapsible reservoir 202 between the inner surface of the middle portion 170 and the outer surfaces of the leaf portions 188 and shoulder
190 of the radial leaf spring 184. Thus, when the reseal member 158 is moved to its second position as shown in Figure 5, the proximal portion 162 of the body 160 extends along and covers the outer surfaces of the leaf portions 188, with the distal portion 166 extending along and covering the base portion 186 of the radial leaf spring 184. However, the middle portion 170 of the body 160 is spaced from the outer surfaces of the leaf portions 188, thus defining the reservoir 202. In this respect, only the proximal portion 162 of the body 160 resides within the central opening 128, with the middle and distal portions 170, 166 of the body 160 and the fully compressed donut spring 196 residing within the interior chamber 126. When the reseal member 158 of the injection site 110 is moved to its second position as shown in Figure 5, the open aperture 180 communicates with both the fluid passage 156 and the reservoir 202. In particular, the open aperture 180 is co-axially aligned with the fluid passage 156, thus creating a continuous flow path between the introducer 198, the fluid passage 156, and the fluid connection 146 to the interior lumen 148 of the flow tube 150 of the manifold 110 of the present invention. The open aperture 180 fluidly communicates with the reservoir 202 via the slots 192 extending between the leaf portions 188 of the radial leaf spring 184. As such, a medicament dispensed from the introducer 198 flows through the open aperture 180, and into the fluid passage 156 and reservoir 202. Importantly, the medicament expelled from the introducer 198 is prevented from leaking into the interior chamber 126 by the seal created by the abutment of the tip 200 of the introducer 198 against the raised lip circumventing the outer surface 176 of the proximal end 164, and by the seal created by the compression of the flange 182 between the dilator projection portion 140 and base portion 186 of the radial leaf spring 184. As will be recognized, the seal created by the flange 152 is
a sliding seal which travels longitudinally along the dilator projection portion 140 as the reseal member 158 is advanced to its second position.
Due to the resiliency of the donut spring 196, the removal of the distally directed pressure from the proximal end 164 causes the radial leaf spring 184 to be proximally withdrawn from over the dilator projection portion 140, thus facilitating the resilient return of the reseal member 158 to its first position, as shown in Figure 3. The return of the reseal member 158 to its first position causes the aperture 180 to resiliently return to its closed configuration. Additionally, as the reseal member 158 moves toward its first position, the resultant forcing of the middle portion 170 of the body 160 into the central opening 128 facilitates the collapse of the reservoir 202 since, as previously explained, the middle portion 170 is compressed against the outer surfaces of the leaf portions 188 when the reseal member 158 is in its first position. Importantly, this collapse of the reservoir 202 causes the fluid previously introduced thereunto to be expelled from therewithin and into the fluid passage 156 via the slots 192 extending between the leaf portions 188 of the radial leaf spring 184. The advantages attendant to this resultant flow of fluid into the fluid passage 156 during the return of the reseal member 158 to its first position will be discussed in more detail below.
As previously explained, in prior art needleless injection sites there is a tendency for blood to be drawn into the fluid line extending into the anatomical passage when the introducer is withdrawn from within the injection site. Such back-flow of blood is attributable to the vacuum created in the fluid line when the introducer is withdrawn "from within the prior art injection site. Advantageously, the collapse of the reservoir 202 of the injection site 110 in the aforementioned manner prevents a vacuum from being
created within the interior lumen 148 when the reseal member 158 moves from its second position (shown in Figure 5) to its first position (shown in Figure 3) . In this respect, the flow of fluid from the reservoir 202 into the fluid passage 156 creates zero or positive pressure within the fluid passage 156 and the interior lumen 148 coupled thereto, thus preventing blood from being drawn thereinto. Advantageously, the absence of blood within the interior lumen 148 prevents any undesirable coagulation therewithin, and eliminates the risk of inadvertent obstruction of the interior lumen 148 or any connected intravenous tubing.
In the injection site 110, the reservoir 202 is sized so as to displace a volume of fluid which is equal to or greater than the product of the mean internal diameter of the fluid passage 156 extending through the dilator projection portion 140 and the distance of axial travel of the reseal member 158 between its first and second positions. For most applications, the expanded reservoir 202 is sized having a volumetric capacity of approximately 0.035ml which is sufficient to facilitate zero or positive pressure within the fluid passage 156 when the reseal member 158 is returned to its first position. It will be recognized that increasing the diameter of the middle portion 170 of the body 160 facilitates a resultant increase in the volumetric capacity of the reservoir 202. In this respect, an increase in the volume of the reservoir 202 causes positive pressure to be created within the fluid passage 156 when the reservoir 202 is collapsed. Conversely, the diameter of the middle portion 170 may be reduced such that the volume of the reservoir 202 causes zero pressure to be created in the fluid passage 156 when the reservoir 202 is collapsed. As previously explained, the injection site 110, and in particular the housing 116 thereof, is adapted to be fluidly connected to the interior lumen 148.
Due to the configuration of the reseal member 158, in an emergency situation a medicament may be passed into the fluid passage 156 via a needled introducer device rather than through the non-needled introducer 198 previously described. In this respect, when a needled introducer device is utilized, the reseal member 158 will not be moved to its second position to facilitate the opening of the aperture 180. Rather, the needle of the needled introducer device is simply forced through the closed aperture 180 and into the fluid passage 156 of the dilator projection portion 140.
It is additionally contemplated by the present invention that one or more of the one-way needleless injection sites may be replaced by a two-way or bi- directional needleless injection site to allow for a greater variety of applications and use of the present invention.
Additional modifications and improvements of the present invention may also be apparent to those skilled in the art. Thus, the particular combination of the parts described and illustrated herein is intended to represent only one embodiment of the present invention, and is not intended to serve as limitations of alternative devices within the spirit and scope of the invention.