Intravascular valve component with improved valve positioning

An intravascular valve component broadly includes a valve case and a flexible pressure-actuated flow control valve. The valve case includes attached proximal and distal case portions that present respective spaced apart fluid ports and a fluid passageway extending between the ports. The flexible pressure-actuated flow control valve is disposed within the fluid passageway and includes a slitted central valve wall and an annular flange surrounding the central valve wall. The annular flange includes a radially-extending flange wall and a projection extending axially from the flange wall, with the projection engaging one of the case portions to restrict radial movement of the flow control valve relative to the valve case.

BACKGROUND

The present invention relates generally to infusion devices used for the administration of various fluids to patients. More specifically, embodiments of the present invention concern an intravascular valve component for a catheter.

2. Discussion of Prior Art

The use of intravenous devices for the administration of parenteral and other fluids to patients is a common practice. A variety of devices for such purposes have been proposed in the past, such as a simple length of tubing having a fitting on one end for making connection with a source of fluid (e.g., a bottle or flexible bag), while the other end is provided with a needle or catheter which may be inserted into the vein of a patient. A persistent problem with prior infusion devices is referred to as blood reflux, or the tendency for small amounts of blood from the patient to be drawn into the infusion apparatus. Blood reflux can occur in prior art devices, for example, when a gravity supply fluid source is empty or when a cannula is removed from a septum or port.

Prior art pressure-activated infusion devices that reduce blood reflux using a flexible check valve are problematic due to manufacturing-related issues. Flexible check valves are notoriously difficult to align relative to the internal passage of the valve housing. Off-axis misalignment of the check valve can cause the valve to inadvertently or prematurely open. Furthermore, prior art check valves are also known to shift or “squirm” within the housing, often when the valves are seated and secured in the housing. This inadvertent movement can also cause valve misalignment and improper operation.

There is accordingly a need in the art for improved intravascular devices equipped with a valve component that eliminates the possibility of blood reflux and can be reliably manufactured.

SUMMARY

Embodiments of the present invention provide an intravascular valve component that does not suffer from the problems and limitations of the prior art devices set forth above.

A first aspect of the present invention concerns an intravascular valve component that broadly includes a valve case and a flexible pressure-actuated flow control valve. The valve case includes attached proximal and distal case portions. The case portions present respective spaced apart fluid ports and a fluid passageway extending between the ports. The flexible pressure-actuated flow control valve is disposed along the fluid passageway to control fluid flow therethrough. The valve includes a slit central valve wall and an annular flange surrounding the central valve wall. The annular flange includes a radially-extending flange wall and a projection extending axially from the flange wall. One of the case portions presents an opening that receives the projection therein. The flange wall is engagingly received between the attached case portions, with the projection engaging the one of the case portions to restrict radial movement of the flow control valve relative to the valve case.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning toFIGS. 1,2, and3, a catheter assembly10selected for illustration generally includes an injection site12, a peripheral catheter14secured to the distal end of the site12, and a cannula16removably inserted into the proximal end of the injection site. The injection site12is constructed in accordance with a preferred embodiment of the present invention. Although the injection site12is shown with the peripheral catheter14and cannula16, it will be appreciated that the site12can be used in other applications. For example, the injection site12could be used with a central venous catheter (CVC), another intravascular catheter, or a needle. Furthermore, the injection site12could be used with other types of connection components, tubing, etc. Moreover, as will be appreciated, the principles of the present invention are not limited to an injection site, but rather encompass any intravascular component utilizing the inventive valve arrangement described herein. Yet further, the illustrated catheter assembly10is similar in many respects to the assembly disclosed in co-pending U.S. application Ser. No. 11/277,471, filed Mar. 24, 2006, entitled INTRAVENOUS INJECTION SITE WITH SPLIT SEPTUM AND PRESSURE ACTIVATED FLOW CONTROL VALVE, which is hereby incorporated in its entirety by reference herein.

The illustrated injection site12preferably includes a support body18, a proximal split septum unit20, a distal luer lock fitting22, and a unitary pressure-actuated flow control valve24. Again, it will be shown that the injection site12could be alternatively configured with respect to the critical aspects of the present invention. As used herein, the terms “distal” and “proximal” refer, respectively, to directions toward and away from a patient.

In more detail, the illustrated peripheral catheter14is itself entirely conventional and includes an annular proximal base26with diametrically opposed connection tabs28for threaded connection to the fitting22. The catheter14also includes a distally extending barrel30and cannula32secured to the distal end of the barrel30. As is customary, the cannula32is inserted into a patient so that medicaments can be injected and fluids can be aspirated via the injection site12. As previously mentioned, the principles of the present invention are equally applicable to other catheter designs, as well as other components permanently or removably secured to the injection site12.

The illustrated cannula16is also conventional in construction and preferably includes a proximal annular base34and an externally ribbed barrel36terminating in an elongated injection lumen38. The base34is preferably provided with diametrically opposed connection tabs40configured for threaded connection with a standard luer lock fitting. It is particularly noted that the cannula16is a so-called “blunt cannula,” preferably formed of a relatively rigid plastic and intended to provide needleless connection with a septum. Although a needle could conceivably be used with the injection site12, those ordinarily skilled in the art will appreciate that a split septum is typically designed for use with a blunt cannula. The illustrated cannula16is configured to be attached to other components for transferring fluid via the injection site12(in either of infusion and aspiration directions), such as tubing, a syringe, or a gravity supply fluid source.

Turning toFIGS. 4-7, the support body18serves to support and interconnect the septum unit20and luer lock fitting22. The support body18preferably comprises a molded synthetic resin rigid body and includes a septum well42, a tubular mid-section44, and a cup-like structure that includes a valve seat46and a sidewall48. The septum well42presents a socket for receiving the septum unit20, and the socket is partly defined by a distal septum-engaging surface50and an annular interior groove52adjacent a proximal end of the septum well42. As will be discussed, the surface50is designed to restrict distal displacement of the septum when the cannula16is inserted therein and, more preferably, pre-compress the septum prior to cannula insertion. The surface50projects proximally to provide the desired degree of pre-compression. Specifically, the surface50is rounded with a central apex53, and the surface50preferably extends in a proximal direction at least about 0.015 of an inch (measured axially from the distalmost circumferential periphery of surface50to the central apex53). More preferably, the “height” of the surface is about 0.026 of an inch. However, the principles of the present invention are equally applicable where the septum well42is alternatively configured or where the support body18is devoid of the septum well42(e.g., where the injection site12does not include the septum unit20). It is also possible for the inventive aspects of the valve component to be used without the septum unit20.

The mid-section44is integrally formed with and extends distally from the septum well42and presents an axially-extending proximal passageway54. The passageway54extends through the central apex53of the septum-engaging surface50. The preferred passageway54has a diameter that ranges from about 0.099 inches to about 0.112 inches. The mid-section44serves as the fluid connection between the septum well42and the cup-like structure that holds the flow control valve24, and thereby provides a space for receiving the distal end of cannula16during cannula insertion (seeFIG. 5). However, it is also within the scope of the present invention to have additional or alternative structure provided to interconnect the cup-like structure and septum well42. Furthermore, the support body18could be devoid of the mid-section44so that the septum well42and cup-like structure are directly connected.

Turning again toFIGS. 4-7, the cup-like structure is configured to hold the flow control valve24, as will be discussed further. The valve seat46comprises a radially-extending wall attached to the distal end of the mid-section44and presents a proximal flange-engaging face56. The sidewall48comprises an annular wall that presents interior, annular, proximal and distal axial surfaces58,60that are joined by a shoulder62(seeFIG. 7). The sidewall48extends endlessly about the valve seat46and is preferably integrally formed with the valve seat46. Preferably, the illustrated surfaces56,58,60,62cooperatively form a socket that fluidly communicates with the passageway54and is configured to receive the flow control valve24and luer lock fitting22. However, for some aspects of the present invention, the preferred socket could be alternatively configured to receive the luer lock fitting22and flow control valve24. The sidewall48presents an outermost diameter of the injection site that is preferably less than about one (1) inch and, more preferably, is less than about 9/16 of an inch.

The split septum unit20preferably includes a resilient elastomeric septum body64, and an annular rigid synthetic resin septum holder66. However, the principles of the present invention are applicable where the septum unit20does not include the holder66. The illustrated holder66has opposed, annular, proximal and distal ends68,70, and is disposed about body64. The outer surface of the holder66also has an outwardly projecting, annular detent72. As illustrated, the outer periphery of resilient body64has an annular groove74, while the inner surface of holder66is equipped with a mating, annular rib76; the interfit of rib76into groove74securely fastens the holder66to body64. The internal diameter of the ring-shaped septum holder66and the outer diameter of the septum body64are preferably dimensioned to closely complement one another, whereby the septum holder66provides little or no pre-loading of the septum body64.

The body64also presents a split78extending fore and aft between proximal and distal faces80,82thereof. This allows insertion of cannula16through the septum unit20, as will be described. The split78is preferably a tri-slit (or Y-shaped slit), although a linear split or other split configurations are entirely within the ambit of the present invention. However, those ordinarily skilled in the art will appreciate that certain principles of the present invention are not limited to the illustrated septum design. For example, the septum holder66is not always required or the design of the septum body64may be varied, such as changing the configuration of the split. Furthermore, for some aspects of the present invention, the injection site could be devoid of the septum unit20entirely (e.g., the site12may alternatively include a luer lock connection in place of the split septum).

In the illustrated embodiment, the holder66projects proximally from the well42so that the proximal terminal face68of the holder66is spaced proximally from the proximal terminal face80of the support body18. Moreover, the body64and holder66are preferably configured to present a substantially coplanar proximal septum surface (cooperatively defined by faces68and80). This arrangement provides a generally smooth swabable surface that greatly enhances the cleanliness of the site12. However, it is entirely within the ambit of certain aspects of the present invention to provide the site12with an alternative proximal configuration. For example, the proximal surfaces of septum body64, septum holder66, and well42may be axially offset relative to one another. Furthermore, if desired, the proximal face of the well42could also be coplanar with the faces68and80. In the preferred embodiment, the faces68and80are not coplanar until the unit20is received within the well42, whereupon the septum body64is preloaded and deflected proximally into flush relationship with the proximal face68(seeFIGS. 4 and 7).

The septum unit20is received within well46, with the septum body64preferably being preloaded as previously described. Furthermore, the unit20is inserted into well42until the detent72is seated within groove52, which provides further pre-compression (or at least resistance to radial deflection) of the septum body64. Yet further, as the septum unit20is seated within the well42, the outer periphery of distal face82of body64comes into firm contact with the protruding septum-engaging surface50. Consequently, the body64is compressed by and assumes a shape complemental to the surface50(seeFIGS. 4-7). Additional details and advantages concerning the preferred septum unit24and the interconnection between the septum well42and septum unit24are disclosed in the above-incorporated U.S. application Ser. No. 11/277,471.

Turning toFIGS. 2,2a, and4-7, the luer lock fitting22is preferably a unitary fitting molded from a rigid synthetic resin. The fitting22includes a proximal annular valve seat84, a distal annular inner barrel86, and a distal, annular, outer, connection wall88. The fitting22also presents a proximal connection end90with proximal and distal axial surfaces92,94, and proximal and distal shoulders96,98and is designed to be received by the distal socket of the support body18(seeFIG. 7). The connection end90is designed to mate with the sidewall48so that respective surfaces58,92, shoulders62,96, and surfaces60,94engage one another to interconnect the fitting22and the support body18and secure the flow control valve24, as will be discussed further. As best seen inFIG. 7, the annular base34of peripheral catheter14is threaded into the fitting22, between the inner barrel86and outer connection wall88. The fitting22also presents an axially-extending distal passageway100that extends through the inner barrel86and valve seat84. While the fitting22is preferably configured as a luer lock fitting, the principles of the present invention are equally applicable where fitting22includes a different type of connector for attachment to the catheter14(or for attachment to other infusion/aspiration set components such as a needle or tubing).

The valve seat84also presents a distal annular flange-engaging face102spaced radially between the proximal surface92and the passageway100, with the distal face102preferably including an endless annular groove104for receiving and holding the flow control valve24precisely between the support body18and fitting22. However, it is also within the scope of the present invention where the valve seat84is alternatively configured to receive the flow control valve24, as will be discussed further.

Turning toFIGS. 3,3a, and4-7, the flow control valve24is configured to selectively permit infusion and aspiration fluid flow through the injection site12and includes a peripheral flange106and a concavo-convex, substantially dome-shaped central body108surrounded by the flange106. The body108and flange106are preferably integrally formed from resilient silicone, but could include another synthetic resin material. The body108preferably comprises a wall110that presents concave and convex surfaces110a,110b. The wall110also presents a wall apex and a thickness that decreases progressively to the apex. The body108also includes a rib112extending along the concave surface of the wall110. Yet further, the body108presents opposed interior valve edges114that extend perpendicularly relative to the rib112and extend axially through the body108to define a slit116(seeFIGS. 4-7). Additional preferred features of the body108are disclosed in U.S. patent application Ser. No. 10/304,833, filed Nov. 26, 2002, entitled PRESSURE ACTUATED FLOW CONTROL VALVE, which is hereby incorporated in its entirety by reference herein.

The flange106includes an endless annular flange wall118surrounding and attached to the body108(seeFIG. 3a). The flange106also includes an endless annular valve-seating projection120extending distally from the flange wall118and spaced radially between an outermost edge122of the flange wall118and the body108. Preferably, the projection120is spaced radially outwardly from the body108to permit the edges114to flex between open infusion and aspiration configurations, as will be discussed. The principles of the present invention are also applicable where the projection120is alternatively configured to provide a mechanism for precisely seating the flow control valve24within the injection site12. For instance, the projection could extend proximally from the flange wall118. Furthermore, multiple projections120could extend distally and/or proximally from the flange wall118to secure the flow control valve24. For example, the projection120could comprise multiple arcuate segments that are spaced circumferentially from one another and cooperatively extend about the body108. Alternatively, the projection120could include multiple radially-spaced segments.

The flow control valve24is assembled between the support body18and fitting22by positioning the valve24on valve seat84. In particular, the apex of the valve24is inserted into a proximal end of the passageway100, and the projection120is inserted into the annular groove104. The projection120and groove104are preferably shaped to guide the flow control valve24into axial alignment with the fitting22. Preferably, the groove104and projection120are complementally shaped so that the projection120fits snugly within the groove104and the flow control valve24is coaxially aligned with the fitting22(thereby positioning the dome-shaped central body108concentrically within the passageway100). In this manner, the interengagement between the groove104and projection120restricts relative radial movement between the flow control valve24, support body18, and fitting22. In addition, the groove104and projection120permit the flow control valve24to be selectively angularly rotated about the valve axis and relative to the support body18and fitting22, although this is likely unnecessary with the illustrated embodiment because of the symmetrical construction of the control valve24.

The illustrated configuration of groove104and projection120is preferred for axially aligning the flow control valve24within the injection site12. However, it is also within the ambit of the present invention where the valve seat84presents an alternative opening to receive the projection120and thereby axially (and perhaps rotationally) align the flow control valve24. For instance, the valve seat84could present multiple openings to receive complemental projecting segments. It is also within the ambit of the present invention where the projection120extends proximally from flange wall118and is received by a groove in valve seat46. Furthermore, both valve seats46,84could include grooves for receiving complemental oppositely extending projections of the flow control valve24.

The flow control valve24is also positioned onto the valve seat46by locating a proximal surface of the flange wall118against the flange-engaging face56. As discussed previously, the fitting22is secured to the support body18by inserting the connection end90into the distal socket of the support body18. The support body18and fitting22are further secured by attaching respective adjacent pairs of surfaces using a conventional ultrasonic welding process to form an hermetic seal between the support body18and fitting22. The principles of the present invention are also applicable where the support body18and fitting22are alternatively attached to one another, e.g., where the support body18and fitting22are attached by a snap-fit interengagement or adhered to one another using a suitable adhesive.

With the connection end90inserted, the support body18and fitting22cooperatively present an internal valve chamber that receives the flow control valve24. The faces56,102engage the flange wall118on corresponding sides and compress the flange wall118into a compressed state so as to firmly hold the valve24within the injection site12. More preferably, the support body18and fitting22are interconnected so that a thickness dimension T (seeFIG. 3a) of the flange wall118is axially compressed from an uncompressed state to the compressed state by an amount that ranges from about 0.003 inches to about 0.008 inches. Most preferably, the amount of compression of the thickness dimension T between uncompressed and compressed states is about 0.005 inches.

The flange wall118also presents an outermost diameter D1that preferably ranges from about 0.341 inches to about 0.355 inches. Also, the outermost diameter D1is preferably less than an outermost chamber diameter D2(seeFIG. 7). More preferably, the outermost diameter D1ranges from about 0.010 inches to about 0.030 inches smaller than the chamber diameter D2when the flange wall118is in the uncompressed state. Most preferably, the outermost diameter D1is about 0.020 inches smaller than chamber diameter D2. This configuration provides a slight clearance between the flange wall118and support body18. As a result, the illustrated flow control valve24can be precisely coaxially aligned with the support body18, fitting22, and passageways54,100, and the flange wall116can be compressed between the support body18and fitting22while permitting the central body108to flex normally to allow aspiration and infusion flow. In particular, it has been found that this “loose fit” between the installed flow control valve24and axial surface58allows the projection120to align the flow control valve24to the valve seat84and restricts inadvertent off-axis positioning of the valve24relative to the support body18and fitting22. Furthermore, the loose fit between the outermost edge122and axial surface58promotes normal opening of the slit116for injection and aspiration flow, with inadvertent or premature opening of the slit being restricted. Thus, the illustrated injection site12is designed to minimize valve failures, particularly those that result from injection site manufacturing and assembly.

Turning toFIGS. 4 and 6, the valve24is preferably designed to selectively prevent fluid flow in the proximal direction (corresponding to aspiration flow through the injection site12). More particularly, the valve24prevents proximal flow when an aspiration pressure differential (i.e., where the pressure against the convex surface110bof the wall110is greater than the pressure against the concave surface110aof the wall110) across the valve24is below a set aspiration amount (seeFIG. 4). The set aspiration amount is generally greater than the venous pressure (relative to atmospheric pressure) of the patient when fluid is not being injected or aspirated through the injection site12. That is to say, when the valve24experiences the typical venous pressure of the patient, the corresponding aspiration pressure differential is less than the set aspiration amount and is not sufficient to open the valve24(i.e., the edges114are in sealing engagement with each other in the closed configuration). However, when it is desired to aspirate fluid across the valve24, fluid can be drawn through the injection site12by reducing the fluid pressure on a proximal side of the valve24(e.g., by drawing fluid with a syringe) so that the aspiration pressure differential exceeds the set aspiration amount. This causes the valve24to open (i.e., as edges114shift proximally and away from each other into the open aspiration configuration) and allow aspiration flow through passageways54,100(seeFIG. 6).

Turning toFIGS. 4 and 5, the valve24is also preferably designed to selectively prevent fluid flow in the distal direction (corresponding to infusion through the injection site12) when the valve is in the closed configuration. The valve24prevents distal flow when an infusion pressure differential (i.e., where the pressure against the concave surface110aof the wall110is greater than the pressure against the convex surface110bof the wall110) across the valve24is below a set infusion amount. When an external pressure is applied to a proximal side of the valve24(e.g., by injecting fluid from a syringe or other fluid supply) and the infusion pressure differential exceeds the set infusion amount, the valve24opens into the open infusion configuration (where the edges114are shifted distally and away from each other) to allow infusion flow through passageways54,100(seeFIG. 5). It is also noted that the valve24is preferably configured so that the set aspiration pressure differential required to open the valve24is greater than the set infusion pressure differential required to open the valve24.

In operation, the injection site12permits infusion flow from the cannula16to the peripheral catheter14when the infusion pressure differential exceeds the set infusion amount. During infusion, the interior valve edges114are shifted in the distal direction and at least partly away from each other to open the slit116and allow infusion flow to pass from the proximal passageway54to the distal passageway100(seeFIG. 5). Similarly, the injection site12permits aspiration flow from the catheter14to the cannula16when the aspiration pressure differential exceeds the set aspiration amount. During aspiration, the interior valve edges114are shifted in the proximal direction and at least partly away from each other to open the slit116and allow aspiration flow to pass from the distal passageway100to the proximal passageway54(seeFIG. 6).