Patent Description:
For clinicians to achieve vascular access success when using a catheter assembly, a variety of factors are considered. As catheter assemblies change from using large gauge needles to small gauge needles, stability becomes increasingly difficult to maintain. Improving rigidity and reducing deflection within the catheter assembly provides a clinician improved stability and greater control during insertion. Different features in the catheter assembly can be constrained to minimize motion. However, large features and complex profiles with tight tolerances are difficult to consistently manufacture during production. Also, close circular tolerance fits may not be adequate to sufficiently reduce motion. Further, different insertion techniques can affect stability and control when used by the clinician.

Further stability challenges are encountered in a blood control catheter assembly. An exemplary blood control catheter assembly is disclosed in <CIT>. Since a valve and a valve actuator are disposed inside a catheter hub, limited space is available inside the catheter hub to provide a stable engagement surface for a needle tip shield or mating components such as a grip or a needle hub. The position of luer threads and appropriate clearance for the luer threads to function properly are additional considerations. Size and shape constraints also factor into creating a more stable and rigid catheter assembly. Thus, a geometrically simple and compact catheter assembly design with increased manufacturability and clinician friendly features is desired. <CIT> discloses a prior art catheter assembly as defined in the preamble of claim <NUM>.

It is an aspect of the present invention to provide improved connection features between a catheter hub and a housing, such as a needle protection member, a needle tip shield or mating components such as a grip or a needle hub, in a catheter assembly. The connection features advantageously provide a geometrically simple and compact catheter assembly design that can be manufactured inexpensively and provides stability and rigidity for successful vascular access by a clinician.

The foregoing and/or other aspects of the present invention can be achieved by providing a catheter assembly comprising a catheter, a needle having a sharp distal tip and disposed within the catheter, a catheter hub connected to the catheter having the needle passing therethrough, and a housing for enclosing the sharp distal tip of the needle, wherein an external surface of the catheter hub and an internal surface of the housing each include one of a channel member and a raised portion that interfit to restrict motion between the catheter hub and the housing.

The foregoing and/or other aspects of the present invention can also be achieved by providing a catheter assembly comprising a catheter, a needle having a sharp distal tip and disposed within the catheter, a catheter hub connected to the catheter having the needle passing therethrough, the catheter hub including a valve that selectively permits or blocks a flow of fluid through the catheter, and a valve actuator that moves between a first position and a second position, and a housing that encloses the sharp distal tip of the needle, wherein an external surface of the catheter hub and an internal surface of the housing each include one of a channel member and a raised portion that interfit to limit movement between the catheter hub and the housing.

Additional and/or other aspects and advantages of the present invention will be set forth in the description that follows, or will be apparent from the description, or may be learned by practice of the invention.

The above aspects and features of the present invention will be more apparent from the description for the exemplary embodiments of the present invention taken with reference to the accompanying drawings, in which:.

<FIG> illustrates a catheter assembly <NUM> including a hollow introducer needle <NUM> disposed in a catheter <NUM>. The needle <NUM> includes a sharp distal end for insertion into a skin of a patient. During operation, the clinician inserts the needle <NUM> and the catheter <NUM> into the patient's skin, but the needle <NUM> is removed soon after insertion. The catheter <NUM> remains within the patient's skin for future fluid exchange.

As illustrated in <FIG> and <FIG>, the catheter <NUM> is connected to a catheter hub <NUM>. The catheter hub <NUM> includes one or more finger tabs <NUM> that are of different heights extending from a top surface. The finger tabs <NUM> aid the clinician to hold and stabilize the catheter assembly <NUM> when inserting the needle <NUM> and catheter <NUM> into the skin of the patient, as well as to secure the catheter assembly <NUM> to the patient after catheter <NUM> insertion.

The catheter hub <NUM>, as illustrated in <FIG>, can include a pair of wings <NUM> on opposing sides of the catheter hub <NUM>. Similar to the finger tabs <NUM>, the wings <NUM> also aid the clinician to hold and stabilize the catheter assembly <NUM> when inserting the needle <NUM> and catheter <NUM> into the skin of the patient, as well as to secure the catheter assembly <NUM> to the patient after catheter <NUM> insertion. The wings <NUM> are secured to the skin of a patient by adhesive, tape or film, for example. Additional features of the catheter hub <NUM> are described below.

The catheter assembly <NUM> can further include a needle protection member <NUM> also known as a needle tip shield. The needle protection member <NUM> has an internal spring clip <NUM> that locks the distal end of the needle <NUM> inside the needle protection member <NUM>. Specifically, the spring clip <NUM> contacts the side of the needle <NUM> under a spring force during use. At the same time, the spring clip <NUM> interlocks with the catheter hub <NUM> to lock the needle protection member <NUM> to the catheter hub <NUM>.

In another embodiment, the needle protection member <NUM> is replaced by mating components such as a grip or a needle hub. These features are all generally identified as a housing <NUM>.

After the needle <NUM> is used, the distal end of the needle <NUM> is retracted from the catheter hub <NUM> and enters into the needle protection member <NUM>. Upon sufficient entrance of the distal end of the needle <NUM> into the needle protection member <NUM>, a locking action secures the distal end of the needle <NUM> to prevent further use and needle contamination. In other words, the spring clip <NUM> is released from the side engagement with the needle <NUM> to expand and block the movement of the needle <NUM> back into the catheter hub <NUM>. At the same time, the spring clip <NUM> disengages from the catheter hub <NUM> to reverse the interlock between the catheter hub <NUM> and the needle protection member <NUM>. Additional features of the needle protection member <NUM> are described below.

<FIG> illustrates a cross sectional view of a typical blood control catheter assembly <NUM>. The features disclosed in this embodiment are similarly present in <FIG> and <FIG>. Specifically, the catheter hub <NUM> includes a valve <NUM> that selectively permits or blocks the flow of fluid between the catheter <NUM> and a distal end of the catheter hub <NUM>. The catheter hub <NUM> also encloses a valve actuator <NUM> that selectively penetrates and disengages from the valve <NUM> to permit or block fluid communication. The valve actuator <NUM> moves between a first position where the valve <NUM> is disengaged (closed) and a second position where the valve <NUM> is penetrated (open).

A return member <NUM> in the form of a coil spring surrounds the valve actuator <NUM> and floats within an inner diameter of the catheter hub <NUM>. When the clinician engages and moves the valve actuator <NUM> to pierce the valve <NUM> in the second position, the return member <NUM> urges the valve actuator <NUM> to disengage the valve <NUM> and return to the first position. Subsequently, when the clinician disengages the valve actuator <NUM>, the valve actuator <NUM> moves back to the first position and the valve <NUM> closes.

The catheter hub <NUM> includes luer threads <NUM> and a collar <NUM> that are disposed at a proximal end of the catheter hub <NUM>. The catheter hub <NUM> is configured to be selectively engaged and secured to the needle protection member <NUM> via the spring clip <NUM> and the collar <NUM> in the manner described above. The luer threads <NUM> can be, for example, ISO <NUM>-<NUM> threads. The luer threads <NUM> are configured to engage a female connector to exchange fluid, as well as provide rotational stability about the z-axis <NUM> of the catheter assembly <NUM>. The luer threads <NUM> are disposed on the sides of the catheter hub <NUM>, whereas the collar <NUM> is circumferentially disposed on the catheter hub <NUM>. Further details of the components of the catheter hub <NUM> described in this embodiment are disclosed in <CIT>.

<FIG> illustrate the various features of the connection mechanism in the catheter assembly <NUM> of <FIG> between the catheter hub <NUM> and the needle protection member <NUM>. In view of the problems in the art described above, three main factors have been determined to address and mitigate the concerns of stability and undesired movement in the catheter assembly <NUM>.

The first factor is evaluating the fit between the catheter hub <NUM> and the needle protection member <NUM>. The closer the fit, the better the assembly is able to minimize undesirable motion. However, requiring tight tolerances in the manufacturing of the catheter hub <NUM> and the needle protection member <NUM> is not desired because tight tolerances are difficult to maintain in high volume production.

The second factor is evaluating the distance between two support points in the engagement between the catheter hub <NUM> and the needle protection member <NUM> to reduce deflection in the catheter assembly <NUM>. Increasing the distance or length between the support points provides a maximum mechanical or geometric advantage. It is advantageous to position the support points to form a long bearing surface and increase overall stability. Further, the large distance between the support points advantageously results in less free movement and less deflection at the distal tip of the needle. However, size, length and shape constraints limit the available space and amount of possible mechanical advantage that can be designed into the catheter assembly <NUM>.

The third factor is evaluating how many degrees of freedom the catheter assembly <NUM> is constrained by. As illustrated in <FIG>, the z-axis <NUM> represents the centerline of the catheter assembly <NUM>. As illustrated in <FIG>, the x-axis <NUM> represents the horizontal axis of the catheter assembly <NUM> and the y-axis <NUM> represents the vertical axis of the catheter assembly <NUM>. These three axes <NUM>, <NUM>, <NUM> can be constrained by design in the catheter assembly <NUM> to restrict motion and improve rigidity during use by the clinician. However, the design challenge is to restrict as much motion as possible using simple and small features that are not difficult to manufacture.

Additional considerations are necessary for a blood control catheter assembly <NUM>. Specifically, as illustrated in <FIG>, the valve <NUM> and the valve actuator <NUM> occupy much of the internal space in the catheter hub <NUM>. Further, a proximal end of the valve actuator <NUM> is disposed near a proximal end of the catheter hub <NUM> where the luer threads <NUM> are located. This positioning allows the valve actuator <NUM> to be properly engaged by a male luer during operation so that the valve actuator <NUM> can move between first and second positions to penetrate and disengage the valve <NUM>.

Accordingly, as illustrated in <FIG>, there is minimal area or length for engagement and internal support at the inner diameter of the catheter hub <NUM>. As a result, a shorter length is available which can decrease the potential mechanical advantage, create a weak and loose engagement, and reduce the stability and rigidity of the catheter assembly. As described below, the features of the presently disclosed connection mechanism remedy the shortcomings of current catheter assemblies.

<FIG> and <FIG> illustrate the needle protection member <NUM> or tip shield that encloses and secures a distal end of the needle <NUM> after use. The needle protection member <NUM> includes a raised portion <NUM> disposed at a distal, internal surface. The raised portion <NUM> is one aspect of the connection mechanism. The raised portion <NUM> is preferably a rectangular, tongue or rail shaped member that protrudes and extends from the internal surface toward a centerline of the needle protection member <NUM>. The raised portion <NUM> is preferably disposed at a top surface of the internal surface of the needle protection member <NUM>. It is contemplated, however, that the raised portion <NUM> can be located at any angular position on the internal surface of the needle protection member <NUM>.

A chamfer <NUM> is disposed at a distal end of the raised portion <NUM>. The chamfer <NUM> advantageously aids in assembly by providing a smooth engagement with the other part of the connection mechanism as described below. In another embodiment, the raised portion <NUM> includes a rounded edge or a radius instead of the chamfer <NUM> to provide similar benefits.

The raised portion <NUM> has a thickness <NUM> that spans a width, or horizontal distance of engagement, a length <NUM> that spans a distance along a centerline of the needle protection member <NUM>, and a depth <NUM> that spans a vertical distance of engagement. The thickness <NUM> is minimized to satisfy overall size constraints while being large enough to provide one degree of freedom constraint in the x-axis <NUM>.

The length <NUM> of the raised portion <NUM> is advantageously maximized to increase the mechanical advantage while adhering to overall size constraints. The length <NUM> also provides one degree of freedom constraint in the z-axis <NUM>.

The depth <NUM> spans the vertical distance and is sized to ensure engagement with the other part of the connection mechanism for proper operation. At the same time, the depth <NUM> avoids interference with other features of the needle protection member <NUM> and/or components of the catheter assembly <NUM> as described below. The depth <NUM> also provides one degree of freedom constraint in the y-axis <NUM>.

The distal end of the needle protection member <NUM> also includes a support portion <NUM>. The support portion <NUM> is disposed substantially at an opposing side of the raised portion <NUM>. The support portion <NUM> is disposed a bottom surface of the internal surface of the needle protection member <NUM>. It is contemplated, however, that the support portion <NUM> can be located at any angular position on the internal surface of the needle protection member <NUM> depending on where the raised portion <NUM> is positioned.

The support portion <NUM> and the raised portion <NUM> limit movement of the catheter hub <NUM> and the needle protection member <NUM> in the y-axis <NUM> degree of freedom. Specifically, the support portion <NUM> keeps the depth <NUM> of the raised portion <NUM> engaged to the catheter hub <NUM> and helps provide a close fit. Further description of this engagement is described below.

<FIG> and <FIG> illustrate a channel or groove member <NUM> of the catheter hub <NUM> that provides another aspect of the connection mechanism. The channel member <NUM> is preferably a non-continuous groove that is disposed on an outer surface of the catheter hub <NUM>. Specifically, the channel member <NUM> extends through a portion of a collar <NUM> at the proximal end of the catheter hub <NUM>. The channel member <NUM> is advantageously recessed into the portion of the collar <NUM>, instead of being a feature that extends beyond the height of the luer threads <NUM>.

Thus, the connection mechanism does not increase the overall size of the catheter assembly <NUM>. The channel member <NUM> is not angularly aligned to any portion of the luer threads <NUM> or the catheter hub <NUM> and does not hinder the function of the luer threads <NUM>. Accordingly, the channel member <NUM> advantageously provides the connection mechanism aspect of the catheter assembly <NUM> while not interfering with the function of the ISO <NUM>-<NUM> luer threads <NUM>.

In another embodiment, the channel member <NUM> extends through a portion of the luer threads <NUM> of the catheter hub <NUM>. Since only a portion of the luer threads <NUM> is occupied by the channel member <NUM>, the luer threads <NUM> are still able to function properly.

As illustrated in <FIG>, the channel member <NUM> includes a first channel <NUM> and a second channel <NUM> with a gap <NUM> disposed in between. The first channel <NUM> is disposed in the portion of the collar <NUM> while the second channel <NUM> is disposed distally to the first channel <NUM> and outside of the collar <NUM>. The first and second channels <NUM>, <NUM> are substantially inline.

Walls <NUM> are formed on the catheter hub <NUM> at both sides of the second channel <NUM>. The walls <NUM> have heights that do not extend beyond the height of the collar <NUM> and the luer threads <NUM> to advantageously avoid any potential interference. Also, a height of the walls <NUM> gradually decreases via a smooth curvature to transition into the outer surface of the catheter hub <NUM>. The transition optimizes the strength of the interface between the outer surface of the catheter hub <NUM> and the walls <NUM>.

The gap <NUM> is provided to adequately space the first channel <NUM> from the second channel <NUM> while optimizing the mechanical advantage according to space constraint requirements. Also, the first and second channels <NUM>, <NUM> are manufactured with small tolerances so that a close fit is achieved when mating with the raised portion <NUM> of the needle protection member <NUM>. Although the tolerances are small, the first and second channels <NUM>, <NUM> are not difficult to consistently maintain during manufacturing because of their size and shape.

Thus, the gap <NUM> also advantageously improves manufacturability by shortening the length of engagement of the channel member <NUM>. Without the gap <NUM>, it may be difficult to maintain a small and/or tight tolerance over a long length of the channel member <NUM>. Dividing the channel member <NUM> via the gap <NUM> reduces the length at which the small and/or tight tolerances need to be held to.

The first channel <NUM> includes a chamfer <NUM> at the proximal end of the catheter hub <NUM>. Similar to the chamfer <NUM> in the raised portion <NUM>, the chamfer <NUM> in the first channel <NUM> advantageously aids in assembly by providing a gradual and smooth engagement between the needle protection member <NUM> and the catheter hub <NUM>. According to another embodiment, the catheter hub <NUM> includes a rounded edge or a radius instead of the chamfer <NUM> to provide similar benefits.

The first channel <NUM> also includes a narrowing portion <NUM> at the proximal end of the catheter hub <NUM>. The narrowing portion <NUM> is a V-shaped member that decreases in width from the proximal end of the catheter hub <NUM> and gradually transitions into the first channel <NUM>. The narrowing portion <NUM> gradually tightens the connection mechanism between the catheter hub <NUM> and the needle protection member <NUM>. The narrowing portion <NUM> advantageously aids in assembly by providing a gradual engagement between the channel member <NUM> and the raised portion <NUM> of the needle protection member <NUM>.

The channel member <NUM> includes a width <NUM>, a length <NUM> and a depth <NUM>. The width <NUM> spans a horizontal distance of engagement. The width <NUM> extends through the second channel <NUM> and through a portion of the first channel <NUM>. Specifically, the variable width of the first channel <NUM> at the narrowing portion <NUM> is larger than the width <NUM> at the remaining portion of the first channel <NUM>.

The width <NUM> of the channel member <NUM> cooperates with the thickness <NUM> of the raised portion <NUM> to constrain the connection mechanism between the catheter hub <NUM> and the needle protection member <NUM> in the x-axis <NUM>. Additionally, the width <NUM> is minimized so that the geometry of the luer sealing surface is not affected by sinks during molding. Sinks can arise when plastic shrinks after molding. The width <NUM> of the first channel <NUM> and the width <NUM> of the second channel <NUM>, except for the narrowing portion <NUM>, are substantially equal.

The length <NUM> of the channel member <NUM> spans a distance along a centerline of the catheter hub <NUM>. The length <NUM> is measured from the distal end of the second channel <NUM> to the interface between the first channel <NUM> and the narrowing portion <NUM>. This length <NUM> provides a long bearing surface for increased stability and one degree of freedom constraint in the z-axis <NUM> when the channel member <NUM> engages the raised portion <NUM>. Although the length <NUM> of the channel member <NUM> includes the gap <NUM> between the first and second channels <NUM>, <NUM>, the effective bearing surface is still advantageously maintained because of the separation between the first and second channels <NUM>, <NUM>.

The depth <NUM> of the channel member <NUM> spans the vertical distance of engagement. The depth <NUM> provides an engagement surface between the raised portion <NUM> of the needle protection member <NUM> and the catheter hub <NUM>. Also, the depth <NUM> provides one degree of freedom constraint in the y-axis <NUM>. The depth <NUM> of the first channel <NUM> and the depth <NUM> of the second channel <NUM> are substantially equal.

In another embodiment, the channel member <NUM> and the raised portion <NUM> is a tapered tongue and groove feature. Specifically, the raised portion <NUM> increases in depth <NUM> from the distal end of the needle protection member <NUM> to the end of the raised portion <NUM>. Likewise, the channel member <NUM> increases in depth <NUM> from the proximal end of the catheter hub <NUM> to the end of the second channel <NUM>. In another embodiment, the raised portion <NUM> decreases in depth <NUM> from the distal end of the needle protection member <NUM> to the end of the raised portion <NUM>. Likewise, the channel member <NUM> decreases in depth <NUM> from the proximal end of the catheter hub <NUM> to the end of the second channel <NUM>. Accordingly, in both these embodiments, the channel member <NUM> and the raised portion <NUM> complement each other when fully assembled to provide similar disclosed benefits to the catheter assembly <NUM> as described herein.

According to another embodiment, the raised portion is disposed on the catheter hub <NUM> and the channel member is disposed on the needle protection member <NUM>. Accordingly, the connection mechanism features are reversed to provide similar function and advantages. Further, alternate connection mechanism geometry can be used to limit deflection or gain similar functionality.

<FIG> and <FIG> illustrate the connection mechanism between the catheter hub <NUM> and the needle protection member <NUM> during assembly and after the assembly is secured. The connection mechanism grips and constrains the catheter hub <NUM> and the collar <NUM> to the needle protection member <NUM>. This provides passive safety to the clinician and improves the success of vascular access.

Specifically, as the distal end of the needle protection member <NUM> is drawn toward the proximal end of the catheter hub <NUM>, the raised portion <NUM> is aligned to the channel member <NUM>. The chamfer <NUM> on the raised portion <NUM> first engages the chamfer <NUM> and the narrowing portion <NUM> of the catheter hub <NUM> to advantageously provide smooth and gradual engagement.

At the same time, the support portion <NUM> engages the outer surface of the catheter hub <NUM> to provide further restricted movement in the y-axis <NUM>. As the catheter hub <NUM> travels further into the needle protection member <NUM>, the raised portion <NUM> continues to engage the first channel <NUM> and subsequently the second channel <NUM>.

The assembly of the needle protection member <NUM> and the catheter hub <NUM> is performed as a manufacturing subassembly process. The clinician is not involved in this subassembly process. The clinician only separates the needle protection member <NUM> from the catheter hub <NUM> after the catheter assembly <NUM> is used.

<FIG> illustrates the catheter hub <NUM> fully engaged to the needle protection member <NUM>. In this position, the spring clip <NUM> engages the collar <NUM> to lock the catheter hub <NUM> to the needle protection member <NUM>. The width <NUM> and the length <NUM> of the catheter hub <NUM> engaging the thickness <NUM> and the length <NUM> of the needle protection member <NUM> advantageously secures the catheter assembly <NUM> at one degree of freedom in the x-axis <NUM>.

The depth <NUM> of the channel member <NUM> engaging the depth <NUM> of the raised portion <NUM>, as well as the opposing support portion <NUM> in the needle protection member <NUM>, advantageously secures the catheter assembly <NUM> at one degree of freedom in the y-axis <NUM>. Thus, the lateral movement in the x-axis <NUM> and the radial movement in the y-axis <NUM> between the catheter hub <NUM> and the needle protection member <NUM> are restricted. On the other hand, the transverse motion in the z direction <NUM> between the catheter hub <NUM> and the needle protection member <NUM> is still permitted.

The connection mechanism between the catheter hub <NUM> and the needle protection member <NUM> as described provides little to no support at the internal diameter of the catheter hub <NUM>. Nevertheless, the connection mechanism provides a significant benefit to the catheter assembly <NUM> based on a simple geometry, relatively small features and improved manufacturability. The catheter hub <NUM> is constrained by the needle protection member <NUM> to minimize motion. Specifically, the length <NUM> of the needle protection member <NUM> and the length <NUM> of the catheter hub <NUM> provide improved stability during insertion by the clinician while reducing deflection in the catheter assembly <NUM>. The improved rigidity provides the clinician greater control.

The connection mechanism advantageously does not require tight tolerances which would impair manufacturability. Moreover, the connection mechanism is not a large feature that is difficult to manufacture and does not increase the length or height of the catheter assembly <NUM>. That is, there are no large features in the catheter hub <NUM> that extend around the exterior of the luer threads <NUM>. These advantages including the advantages described above provide an improved catheter assembly <NUM> for the clinician to operate.

The foregoing detailed description of the certain exemplary embodiments has been provided for the purpose of explaining the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated. This description is not necessarily intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Any of the embodiments and/or elements disclosed herein may be combined with one another to form various additional embodiments not specifically disclosed, as long as they don't contradict each other. Accordingly, additional embodiments are possible and are intended to be encompassed within this specification and the scope of the invention. The specification describes specific examples to accomplish a more general goal that may be accomplished in another way.

Claim 1:
A catheter assembly (<NUM>) comprising:
a catheter (<NUM>);
a needle (<NUM>) having a distal tip and disposed within the catheter;
a catheter hub (<NUM>) connected to the catheter having the needle passing therethrough; and
a housing (<NUM>) attachable to the catheter hub, wherein
an external surface of the catheter hub includes one of a channel member (<NUM>) and a raised portion (<NUM>) ;
an internal surface of the housing includes an other of the channel member and the raised portion such that the channel member and the raised portion engage to restrict motion between the catheter hub and the housing;
characterized in that
the channel member includes a first channel (<NUM>) and a second channel (<NUM>) separated by an axial gap (<NUM>).