Patent Description:
At the most basic level, whenever a liquid medication is to be delivered into or through the skin of a patient from an external source, a hollow needle or other type of cannula or catheter device must first be inserted in order to provide a passageway or channel through which the fluid may pass. Once this passageway has been provided, any suitable infusion set or system may be used in conjunction with an appropriate tube or conduit connecting the external source of liquid with the passageway leading to the subcutaneous delivery point to deliver the liquid to the patient at an appropriate delivery rate.

One class of devices that can be used to deliver liquid medications into or through the skin of a patient are known as infusion sets. <FIG> illustrates the components of a known infusion set <NUM>. Infusion sets <NUM> generally comprise a relatively short cannula or catheter <NUM> that is supported by and protrudes from a compact housing <NUM> adapted to receive the infusion fluid via a delivery tube <NUM> connected suitably to other components of a fluid infusion system. For optimum patient comfort during use, the cannula <NUM> is desirably constructed with a high degree of softness and flexibility. The infusion set <NUM> can also include a liquid pump <NUM>, among other devices. An insertion needle <NUM> is normally provided to extend through a lumen formed in the cannula <NUM> to facilitate placement of the cannula <NUM>, either into or through the skin, after which the insertion needle <NUM> is withdrawn to leave the cannula <NUM> in place for fluid infusion into the patient.

The housing <NUM> itself can comprise a cap or fluid connector <NUM> and a base <NUM> that are separable. The base <NUM> is attached to the patient's skin during cannula insertion and the cap <NUM> is attached to the base <NUM> after the insertion needle <NUM> is removed. The base <NUM> is attached to the patient by an attachment means, generally an adhesive pad <NUM> that provides sufficient adhesion to the skin to keep the housing <NUM> in place for several days, but not too much adhesion to cause damage to the patient's skin.

The base <NUM> may also include a septum <NUM> that provides a self-sealing interface. This interface is necessary because the insertion needle <NUM> is used to put the cannula <NUM> in place, as discussed above. The insertion needle <NUM> extends through the septum <NUM> into the cannula <NUM> for cannula placement. After the insertion needle <NUM> is removed and replaced with the cap <NUM>, liquid flows through the delivery tube <NUM> into an interior chamber <NUM> of the base <NUM> via the cap <NUM>. The septum <NUM> seals the chamber <NUM> from the exterior environment after the insertion needle <NUM> has inserted the cannula <NUM> and has been removed. The liquid enters the chamber <NUM> and then the patient through cannula <NUM>.

Unfortunately, many problems exist with the infusion sets of the prior art. For example, prior art infusion sets <NUM> are difficult to assemble once the catheter <NUM> has been inserted into the body. In some prior art infusion sets <NUM>, it is difficult to align the cap <NUM> and base <NUM> of the infusion set <NUM>. Therefore, after cleaning an insertion site, it is difficult to assemble the infusion set <NUM> so that it works properly. Often, the infusion sets <NUM> of the prior art are unidirectional, by which it is meant that the direction of the extension tubing <NUM> with respect to the base <NUM> of the infusion set <NUM> is fixed and cannot be changed once the infusion set <NUM> has been inserted and attached to the skin of the user. Additionally, in some prior art infusion sets, it is difficult to ensure a good seal between the septum <NUM> and the fluid path, and occasionally fluids leak because of this poor seal. Furthermore, in many prior art infusion sets <NUM> it is difficult to mate the cap <NUM> and base <NUM> of the infusion set <NUM> even if proper alignment can be obtained.

Other difficulties are present in the infusion sets of the prior art that relate to the position of the insertion site. In the prior art infusion sets <NUM>, the insertion site is located below the base <NUM>, and therefore cannot be seen by the user alter insertion. Often, infections can occur, which generally are indicated by a slight reddening of the insertion site, followed by soreness and possible other signs of infection. Also, in many infusion sets of die prior art, once alignment and mating are achieved, the cap <NUM> is difficult to remove and re-attach to the base <NUM> of the infusion set <NUM>.

It is therefore desirable to provide an infusion set connecting apparatus that overcomes these and other difficulties associated with the infusion sets of the prior art. <CIT> is considered the most relevant prior art and forms the basis for the preamble of claim <NUM>. It discloses a device for inserting a cannula into tissue, including a cannula, a protective element which can accommodate said cannula, and an operating element for moving the cannula out of the protective element.

The subject matter of the invention is defined by independent claim <NUM>.

The various objects, advantages and novel features of the present invention will be best understood by reference to the detailed description of examples helpful for understanding the present invention and the preferred embodiments which follows, when read in conjunction with the accompanying drawings, in which:.

Several examples and embodiments will now be described in detail with reference to the annexed drawings. Only the embodiment of <FIG> is part of the invention. In the drawings, the same or similar elements are denoted by the same reference numerals even though they are depicted in different drawings.

Referring to <FIG>, an exemplary infusion set <NUM> according to an example helpful for understanding the invention is shown in various views. The infusion set <NUM> comprises a catheter <NUM>, a self sealing separatable junction, an extension tubing <NUM> and a pump <NUM>.

As shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, the self sealing separatable junction comprises a base <NUM> that has a post <NUM> with an undercut <NUM>, the catheter <NUM> and a septum <NUM> to seal the proximal end of the catheter <NUM>. As shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and 5D, a cap <NUM> includes a tube or opening <NUM>, a retention member <NUM>, a method of releasing the retention member <NUM> (not shown), a blunt cannula and blunt cannula cover <NUM> and the extension tubing <NUM> with luer connector (also not shown).

<FIG>, <FIG> and <FIG> illustrate a needle hub assembly <NUM>. The needle hub assembly <NUM> comprises a needle grip <NUM>, and an insertion needle <NUM>. Alternatively, the needle hub assembly can use other needles, such as the exemplary insertion needle <NUM> (see <FIG>), which is a hollow needle that has one or more holes <NUM> configured to perform one or more additional functions as desired (see <FIG>, discussed in greater detail below).

The needle hub assembly <NUM> is used to insert the catheter <NUM> of the infusion set <NUM>, <NUM> into the body of a user so that the catheter <NUM> does not bend or crumple, and is positioned at the correct depth for delivery of the user's medication via the infusion set <NUM>, <NUM>. To insert the catheter <NUM> into the skin of the user, the user grips the needle grip <NUM> and inserts the needle <NUM>, <NUM> through the septum <NUM> of the infusion set <NUM>, <NUM>. The stiffened catheter <NUM>, with the needle <NUM>, <NUM> can then be inserted into the skin of the user, and the infusion set <NUM>, <NUM> can then be affixed to the user's skin with an adhesive patch located on the bottom of the base <NUM> of the infusion set <NUM>, <NUM>.

<FIG> illustrate several views of an exemplary tubing set connector assembly <NUM> that can comprise the cap <NUM>, attached tubing <NUM>, and an exemplary latching mechanism.

In <FIG>, a latching mechanism <NUM> is illustrated as a means to fix the cap <NUM> onto the base <NUM> of the infusion set <NUM>. This latching mechanism <NUM> will be described in greater detail below in reference to <FIG>.

<FIG> illustrate cross-sectional and isometric views of a connection port assembly <NUM>. The connection port assembly comprises the base <NUM> and post <NUM>. The post <NUM> can comprise a substantially cylindrical member extending perpendicular from a substantially flat base <NUM>, but is not limited thereto. As shown in <FIG>, the post and base can be formed as one piece, and the post <NUM> can be further configured to provide a detent, shoulder, or other similarly functioning undercut <NUM> which can be releasably captured by one or more members provided on the cap (not yet shown), and can further be configured to provide a post lead-in surface <NUM>. The undercut <NUM> and post lead-in <NUM> can be used to facilitate the excellent alignment and/or latching features of the infusion sets <NUM>, <NUM>, and are each described in greater detail below.

Referring now to <FIG>, the exemplary cap <NUM> and base <NUM> are illustrated in an attached and secured position, wherein the tube or opening <NUM> of the cap <NUM> aligns with and slidably receives the post <NUM> of the base <NUM> to ensure that all the other interacting elements are in alignment as they engage each other. Both the post <NUM> and tube <NUM> have generous tapered, contoured, inclined or other similarly functioning lead-in areas <NUM>, <NUM> to help guide the cap <NUM> into the correct position on the base <NUM>. <FIG> illustrates a side view of <FIG> rotated about <NUM> °.

After the tube or opening <NUM> has aligned with and slidably received the post <NUM>, the blunt cannula <NUM> penetrates the lower septum <NUM>. The exemplary septa <NUM> are shown in greater detail in <FIG>. Referring now to <FIG>, an exemplary slit <NUM> extends for a certain distance across the lower septum <NUM>, and from top to bottom of the lower septum <NUM>. The lower septum <NUM> is designed to be manufactured to be substantially circular and the slit <NUM> is substantially centered in the lower septum <NUM>. This makes it easier to manufacture the infusion set <NUM>, as no particular orientation of the lower septum <NUM> is necessary in the base <NUM>. <FIG> illustrates the lower septum <NUM> prior to insertion of the blunt cannula <NUM>. The slit <NUM> creates a substantially impenetrable seal from top to bottom, or visa-versa, of the lower septum <NUM>. Thus, after the infusion set <NUM> is installed on the body of the user, and the cap <NUM> is removed (e.g., for bathing), water, soaps and other foreign materials are substantially prevented from entering the area of the skin where the cannula has pierced the skin. The upper septum <NUM> can be configured in a substantially identical manner, but is not limited thereto.

In <FIG>, the blunt cannula <NUM> is shown after it has pierced the lower septum <NUM> through the slit <NUM>. Because each septum <NUM> is made of a deformable resilient material, it deforms around the blunt cannula <NUM>, forming a substantially impenetrable seal around the blunt cannula <NUM>. Upon removal of the blunt cannula <NUM>, the slit <NUM> returns to its original shape as shown in <FIG>, again providing the substantially impenetrable seal between the skin and the outside environment. Further, the exemplary septum <NUM> can be easily sterilized prior to positioning in the device, and can thereafter, be cleaned prior to insertion or re-insertion of the blunt cannula <NUM> to further reduce the risk of infection. When the blunt cannula <NUM> penetrates the lower septum <NUM> during assembly, it allows liquid medication to flow from a luer connector, through the extension tubing <NUM> and the blunt cannula <NUM> past the septum <NUM> and into the catheter <NUM>.

Returning to <FIG>, the retention member <NUM> in the cap <NUM> is configured to releasably and rotably secure the cap to the base as described in greater detail below, and can be spring loaded, and can be configured to provide tapered, contoured, inclined or other similarly functioning lead-in areas <NUM> that allow it to contact and be moved out of position by the post <NUM> lead-ins <NUM> until clear of the lead-ins <NUM> at which point it can be configured to springs under the undercut <NUM> of the post <NUM> as shown in <FIG> and <FIG>, thereby locking the cap <NUM> and base <NUM> together.

<FIG> illustrates an enlarged side view of the post <NUM> and tube or opening <NUM> with their respective lead-ins <NUM>, <NUM>, and <FIG> illustrates an enlarged side view of the post <NUM> and retention member <NUM> with their respective lead-ins <NUM>, <NUM>. The angle Θ, formed to create tube lead-in <NUM>, substantially matches the slope and angle Φ of the post lead-in <NUM>, but is not limited thereto. By providing the slope of the post lead-in <NUM> and the slope of the tube lead-in <NUM>, even if a user misaligns the cap <NUM> somewhat over the post <NUM>, the respective lead-ins <NUM>, <NUM> force the two parts (e.g., the cap <NUM> and the base <NUM>) into alignment. The post <NUM> can then be slide into the interior space of the tube <NUM>, where the post <NUM> encounters retention member <NUM>. As such, <FIG> illustrates an exemplary means for cap and base alignment with minimal user effort.

As illustrated in <FIG>, the retention member <NUM> lead-in <NUM> substantially matches in slope the post <NUM> lead-in <NUM>, but is not limited thereto, so that the user can easily latch the cap <NUM> onto the base <NUM>. The latching is easily accomplished because the spring-loaded, or otherwise elastically-urged retention member <NUM> easily moves away from its initial position (i.e., to the left in the example shown in <FIG>) as the cap <NUM> moves down over the post <NUM>. Once the cap <NUM> has moved down sufficiently such that the blunt cannula <NUM> has pierced the slit <NUM> of the lower septum <NUM>, the retention member <NUM> slides back to the right due to the spring and/or other elastic force, and a detent, shoulder, or other similarly functioning ledge <NUM> comes in contact with and captures the undercut <NUM> of the post <NUM> as shown in <FIG>. Of course, the retention means <NUM> and post <NUM> also interact in the aforementioned manner when removing the cap <NUM> from the base <NUM> at times other then when inserting the cannula <NUM>, or inserting the catheter <NUM> into the user (i.e., removing the cap <NUM> for bathing or exercising). As such, <FIG> illustrates an exemplary means for rotably and removably securing the cap to the base with minimal user effort.

The latching mechanism of the retention member <NUM> allows the user to move the retention member <NUM> against the spring or other elastic urging force, out from under the undercut <NUM> to thereby allow the cap <NUM> to be removed from the base <NUM>. The means of releasing the retention member <NUM> can be integrated in the member <NUM> itself. Exemplary means of releasing the retention member <NUM> are described in greater detail below in regard to <FIG>. The spring force can be created through an actual spring and the retention member <NUM>. The retention member <NUM> can be made integral to the cap <NUM> and/or the spring force can be generated from the natural bending properties of the materials used to make the cap <NUM> and a structural design that allows certain parts to flex in response to properly applied forces.

<FIG> illustrate a first exemplary modification to the infusion set <NUM>. In <FIG>, a top view of the post <NUM> and retention member <NUM> is shown, wherein the post <NUM> further comprises one or more post ribs <NUM> disposed upon an outer circumference, and similarly, the retention member <NUM> can further comprise one or more retention member ribs <NUM> upon the and perpendicular to the ledge <NUM>. The post ribs <NUM> and retention member ribs <NUM> are substantially similar in profile and arrangement (i.e., configured to engage each other in a mating arrangement), such that they may easily interface with each other and thereby preventing or substantially reducing rotational movement of the cap <NUM> about the base <NUM>. The user can therefore lock and unlock the cap <NUM> through the engagement and disengagement of the ribs <NUM>, <NUM>, for rotation of the cap <NUM> into any desired position, knowing that because of the interlocking post and retention member ribs <NUM>, <NUM>, the cap <NUM> will not rotate further after engagement, or at least will greatly resist rotation, once adjusted into the desired position. <FIG> is a side view along lines A-A of <FIG>, and illustrates how the ribs <NUM>, <NUM> are formed on the retention member <NUM> and the post <NUM>, and how they interface and align with each other. In the example shown in <FIG>, the retention member <NUM> has been moved to the left and out of engagement by the retention member releasing means (not shown). The cap <NUM>, therefore, is free to be rotated to a new position. However, in such a rotatable position, the retention member <NUM> has not been disengaged entirely from the base <NUM>, but just from the ribs <NUM> of the post <NUM> of the base <NUM>, thus still securing the cap to the base and providing a good seal with the user's skin.

The infusion set <NUM> provides substantial advantages over prior art designs. As discussed above, the infusion set <NUM> does not require much, if any, general alignment between cap and base, and does not require any rotational alignment when connecting the cap to the base. The cap <NUM> and base <NUM> easily align with one another, and the cap <NUM> can rotate freely about the base <NUM> once the two are attached together, so that the extension tube <NUM> can be rotated to any desired orientation. As seen in <FIG>, the post ribs <NUM> and retention member ribs <NUM> on the post <NUM> and retention means <NUM> allow the user to releasably lock the cap <NUM> at any desired orientation, or change the orientation after first located while the cap and base remain securely attached to each other. With this configuration, the cap does not rotate freely when the ribs <NUM>, <NUM> are engaged, but can still be rotated and attached in any orientation when the ribs <NUM>, <NUM> are disengaged. For example, the device (or elements thereof) can be aligned and secured, then rotated by the user to a desired position and upon user release of the retention member <NUM>, the device will "lock" into place. The user can push a button or element slightly of the retention member <NUM>, and move the cap out of the locked position temporarily to rotational reposition the cap and then, when released, the device will return to the locked position. In such an exemplary example, the features can be provided to allow alignment, positioning and locking, release and repositioning, and return to locked, all as desired by the user and assisted by elements of the device.

Accordingly, the infusion set <NUM> provides further advantages over the prior art in that it allows the user to connect, with a straight-down motion orthogonal to the body, and without having to manipulate any buttons or levers. Further, the infusion set <NUM> has the advantage of providing the post ribs <NUM> and retention member ribs <NUM> that enable the cap <NUM> and base <NUM> to automatically be rotationally locked together. This substantially eliminates the chance of dislodging the catheter <NUM> with any sideways or twisting forces and substantially simplifies the connection process for the user. Accordingly, the cap <NUM> and base <NUM> can be easily aligned, assembled and rotated to a desired position using the features of the exemplary post <NUM>, retention member <NUM>, and corresponding retention means lead-ins <NUM>, <NUM>, <NUM> respectively, as shown and described in <FIG>. Furthermore, because of the design of the angular lead-ins <NUM>, <NUM>, <NUM>, of the post <NUM>, cap <NUM>, and retention means <NUM>, a user can substantially mis-align the cap <NUM> and base <NUM> and yet still easily connect the two, as the two self-align for the final connection. Further, because of the inherent symmetry of the cap <NUM> and the base <NUM>, a particular orientation is not necessary when aligning the cap <NUM> and base <NUM>.

<FIG> is a top perspective view of an exemplary infusion set <NUM> according to an embodiment of the present invention. The infusion set <NUM> according to this embodiment of the present invention comprises a base <NUM> that includes a catheter <NUM> and a means of sealing off a fluid path (i.e., septum <NUM>), an introducer blunt cannula <NUM>, and a top fluid cap <NUM> that is connected to a fluid delivery device, such as a pump <NUM>, via extension tubing <NUM>.

As shown in <FIG> and <FIG>, there is a rotational interlocking means <NUM> on one end of the fluid cap <NUM> and base portion <NUM> of the infusion set <NUM>, and a latching interlocking means <NUM> on the other end of infusion set <NUM>. The rotational interlocking means <NUM> comprises a cylinder <NUM> on the fluid cap <NUM> and a first and second base hook 60A, B on the base <NUM>. <FIG> illustrate top and side views of the base <NUM> to illustrate features in greater detail. The first and second base hook 60A, B comprise hooks with a radius that matches the cylinder <NUM> of the fluid cap <NUM>. That is, the first and second base hook 60A, B comprise hooks with a radius that is configured to rotatably capture the cylinder <NUM> therein. The materials of the hooks and cylinder therefore, can be selected from any suitable material to provide rotation with minimal wear.

The fluid cap <NUM> can rotate in a vertical plane relative to the base <NUM> in an upward direction until the cap <NUM> no longer obstructs the base <NUM> and the base <NUM> is exposed, and can rotate in a downward direction until covering the base <NUM> and snaps into place by the latching interlocking means <NUM>. In one exemplary embodiment of the present invention, the latching interlocking means <NUM> can comprise an upwardly projecting and elastically biased latch <NUM> on the base <NUM> with one or more detents extending therefrom, and an interlocking hole <NUM> on the fluid cap <NUM> for receiving and capturing the upwardly projecting and elastically biased latch <NUM>.

The fluid cap <NUM> further comprises the blunt cannula <NUM> that enters the base <NUM> in an up/down fashion into a septum <NUM> rather than from the side. The insertion needle <NUM> is shown inserted through the blunt cannula <NUM>, and a fluid path is created that runs towards the rotatable connection formed by the rotational interlocking means <NUM>. Once the fluid cap <NUM> is installed, the fluid path is now connected to the blunt cannula <NUM> and the catheter <NUM>.

To disconnect the infusion set <NUM> as shown in <FIG> and <FIG>, the latch <NUM> is pressed forward relative to the infusion set <NUM> (i.e., in the direction of the arrow A), allowing the latch <NUM> to pass through the interlocking hole <NUM> on the fluid cap <NUM>, thereby releasing it from the base <NUM>. The fluid cap <NUM> can then rotate out of position and expose the upper surface of the base <NUM>.

<FIG> illustrate alternative means for connecting the extension tubing <NUM> to the infusion set <NUM> according to the second embodiment of the present invention. In <FIG>, the extension tubing <NUM>, which can be connected to the pump <NUM> of <FIG>, is connected to a tubing connection <NUM> that is connected to the cylinder <NUM> of fluid cap <NUM>. In this exemplary embodiment, the extension tubing <NUM> forms a "tail" from the infusion set <NUM>, in a horizontal manner. In yet other exemplary embodiments of the present invention, the extension tubing <NUM> can be connected to a tubing connection that is located on the center top portion of the fluid cap <NUM> as shown in <FIG>. In this case, the extension tubing <NUM> extends nearly vertically from the fluid cap <NUM>. A user can be provided with both fluid caps <NUM>, thereby providing the user with increased flexibility in administering the medicine to themselves, and in controlling the infusion set profile one in position.

As shown in <FIG>, <FIG> and <FIG>, the fluid cap <NUM> can comprise a top septum <NUM> on an upper surface, and an opening <NUM> extending from a lower surface and surrounding the blunt cannula <NUM>. The base <NUM> can be provided with a lower septum <NUM> on an upper surface, and which is surrounded by a projection <NUM>. When the top <NUM> is rotably assembled with the base <NUM>, the projection <NUM> aligns with and is slidably received by the opening <NUM>. Further, the blunt cannula <NUM> of the cap <NUM> is introduced through the lower septum <NUM> from the top of the lower septum <NUM>, which adds advantages over certain prior art infusion sets, especially in regard to contamination. The infusion set <NUM> according to the second exemplary embodiment of the present invention substantially eliminates the possibility of contamination and infection. The rotational interlocking means <NUM> provides an easy means for connecting the fluid cap <NUM> to the base <NUM>, and the latching interlocking means <NUM> provides an easy method for securing both the fluid cap <NUM> to, and releasing the fluid cap <NUM> from, the base <NUM>.

<FIG>, <FIG> and <FIG> illustrate two methods for inserting the catheter <NUM> into a patient. In <FIG> and <FIG>, the needle <NUM> is inserted through the upper septum <NUM> located in the fluid cap <NUM>. The needle <NUM> passes through the upper septum <NUM> in the blunt cannula <NUM> which passes through the lower septum <NUM>, and finally into the catheter <NUM>. The needle grip <NUM> aids the patient in inserting the needle <NUM>, and once the needle <NUM> is inserted through the blunt cannula <NUM> and catheter <NUM>, the user can then insert the catheter into their body for use to administer liquid medication.

<FIG> illustrates an alternative method for inserting the catheter <NUM> into the patient's body. In <FIG>, the cap <NUM> is not shown but illustrates the exposed upper surface of the base <NUM> that would be provided by rotating the cap <NUM> away from the base. In <FIG>, the user does not insert the needle <NUM> through the upper septum <NUM> in the fluid cap <NUM>. Instead, the user simply inserts the needle <NUM> directly through the lower septum <NUM> in the base <NUM> and through the catheter <NUM>. The catheter <NUM> can then be inserted into the patient's body, and the base <NUM> attached to skin.

The infusion sets can be modified for still further improved performance as desired, such as, for example, to allow a patient to prime the infusion sets <NUM>, <NUM>. Priming is the process whereby liquid medication is pumped into the infusion sets <NUM>, <NUM> before the catheter <NUM> is inserted into the patient's body. The purpose of this is to ensure that the pump <NUM> delivers the proper amount of medication to the patient over a given period of time. If the catheter <NUM> is inserted dry, i.e. with no liquid medication already present, there is a lag between the time the pump <NUM> is started and the time the medication enters the body. If the patient merely tracks the time the pump is on, he or she may be significantly under-medicated.

To prime the infusion set, an exemplary modified needle <NUM> can be used as illustrated in <FIG>. The modified needle <NUM> is hollow and comprises one or more holes <NUM> at a location where, once it is inserted through the blunt cannula <NUM>, the medication <NUM> can enter the needle <NUM> through the hole <NUM> and flow through it. In the infusion set shown in <FIG> and <FIG>, the exemplary hole <NUM> in the modified needle <NUM> would be at a point on the modified needle <NUM> that is just below the upper septum <NUM>. This is fairly close to the needle grip <NUM> as illustrated in <FIG>. The modified needle <NUM> is hollow and comprises the exemplary hole <NUM> at the top close to the needle grip <NUM>. The medication <NUM>, exhibited as the arrows of <FIG>, flows into the infusion set and into the needle passageway <NUM>. The medication <NUM> also flows into the hollow modified needle <NUM> through the hole <NUM>, eventually filling the modified needle <NUM> until it exits at its end (located at the bottom of the blunt cannula <NUM>). The infusion set is now primed, and the patient can more accurately measure the amount of medication administered into the patient's body.

<FIG> is an enlarged cross-sectional view of an exemplary lens arrangement for viewing a catheter-skin insertion site of an infusion set according to another example. The exemplary window arrangement of <FIG> illustrates the example that can be added to any one of the infusion sets disclosed herein, or any other suitable infusion set as desired. The exemplary infusion set <NUM> used to illustrate the lens arrangement can comprise any of the base components <NUM>, <NUM>, of the infusion sets <NUM>, <NUM>, combined with the additional features of any combination of an opening, into which a clear flat lens <NUM> and/or a clear magnified lens <NUM> can be secured. In the following description, for purposes of conciseness only and not in a limiting sense, the description shall be made in reference to the first embodiment of the infusion set <NUM> only.

The base <NUM> of the infusion set <NUM> can include either one or two lenses <NUM>, <NUM> for the user to be able to see the insertion site <NUM> where the catheter <NUM> enters the skin. The lenses <NUM>, <NUM> are, in a preferred embodiment, made of transparent plastic. One skilled in the art can appreciate, however, that other suitable materials can also be used. In yet another exemplary embodiment of the present invention, no lens are provided and instead, an opening can be provided in the base <NUM> through which the user can see the insertion site <NUM> where the catheter <NUM> enters the skin. The clear plastic lenses <NUM>, <NUM> can be designed and molded such that a user can see clearly through them. The base <NUM> can be sealed entirely around the insertion site <NUM> with adhesive tape, or any other adhesive means, as described above. This helps to maintain sterility of the insertion site <NUM> while allowing the user to view it for signs of irritation or infection. The clear flat lens <NUM> typically provides little or no magnification. The clear magnified lens <NUM> is typically curved on either the top, bottom or both surfaces to provide some magnification to assist the user in discerning that the insertion site is either free or not free of infection or irritation.

The use of the clear plastic lenses <NUM>, <NUM> in any of the above-described embodiments <NUM>, <NUM>, or other infusion sets not discussed herein, provides the user with the opportunity to keep the insertion site <NUM> cleaner and more sterile. Furthermore, such example allows the user to detect the first signs of infection at the insertion site, improper insertion or extraction of the catheter <NUM>, or any other irregularity at the insertion site. This is an advantage over the prior art designs that do not provide any means, other than the removal of the base, to monitor the insertion site for infections.

<FIG> illustrate several exemplary septum holding sets that can be added to any or all of the infusion sets disclosed herein, as well as other suitable infusion sets. <FIG> illustrates a first example of an exemplary wedge-in-a-septum arrangement,.

As can be seen in <FIG>, the wedge <NUM> is encapsulated by the septum <NUM> of the infusion set <NUM>. The wedge <NUM> provides one or more shoulders, detent or other features which are captured within a corresponding opening in an inner portion of the septum <NUM>. The wedge <NUM> further comprises a perpendicular member extending downward and slightly beyond the septum <NUM>. In doing so, one function of the wedge <NUM> is to fix in place and locate the catheter <NUM>. The septum <NUM> of <FIG> is then fixed in place and remains in place, regardless of repeated insertions by the needle <NUM> (not currently shown). In an example, the wedge <NUM> can be constructed of metal, plastic or other suitable material or combination of materials.

The exemplary septum-wedge arrangement of <FIG> comprises the catheter <NUM> over a septum-enclosing wedge <NUM> with the septum <NUM> that is housed inside the septum-enclosing wedge <NUM>. As shown in <FIG>, the exemplary septum-enclosing wedge <NUM> comprises an enlarged upper portion to receive, enclose and capture the septum <NUM>, and a narrow lower portion to fit within the catheter <NUM>. In doing so, the septum-enclosing wedge <NUM> is designed such that a top edge <NUM> of the septum-enclosing wedge <NUM> can be forced over the septum <NUM> to prevent dislodgment of the septum from the base assemblies <NUM>, <NUM>, of the infusion sets <NUM>, <NUM>.

Another exemplary septum-wedge arrangement is shown in <FIG>. In <FIG>, the septum-fixing wedge <NUM> is fixed inside the septum <NUM>. In <FIG>, the septum-fixing wedge <NUM> is fixed below the septum <NUM>, which can comprise a recess for receiving the shoulder of the septum-fixing wedge <NUM>, and resides on top of the catheter <NUM> and/or base <NUM>. The exemplary septum holding arrangement shown in <FIG> is a second example of the wedge-in-a-septum arrangement as shown in <FIG>. In <FIG>, the septum <NUM> also encapsulates wedge <NUM>, but not as completely (as described above) as in <FIG>.

In the first, second and third exemplary septum-wedge arrangements, the septum <NUM>, <NUM>, <NUM>, is not free to become dislodged, and remains substantially fixed in location even after numerous insertions of the needle <NUM>. An advantage of the first, second and third exemplary septum-wedge arrangements is that a secondary part is not necessary to hold the septum in place during manufacturing, therefore reducing part inventory and manufacturing costs.

<FIG> illustrate bottom and top views of an exemplary cap retention means <NUM> comprising a flexible cap element <NUM> that can be provided within cap <NUM> or in place of cap <NUM>, and which is secured to the base <NUM> by a retention means <NUM>. The flexible cap element <NUM>, as shown in <FIG>, can be referred to as a dual-sided, flexible-hoop cap element <NUM> comprising sides 102A, 102B, 102C, 102D, and can be used with the infusion set <NUM> that includes the base <NUM>, and all of its attendant features. As described above, the elements to which an exemplary cap is secured is comprised of the base <NUM> which has the post <NUM> with the undercut <NUM>, catheter <NUM> and septum <NUM> to seal the proximal end of the catheter <NUM>. A connection set (i.e., such as the flexible-hoop cap element <NUM>) comprises the tube or opening <NUM>, a retention member, a means for releasing the retention member, the blunt cannula and blunt cannula cover <NUM>, and the extension tubing <NUM> with a luer connector (not currently shown).

Referring to <FIG>, an exemplary operation of the cap retention means <NUM> will now be described. Note that the above-described features and details in regard to the cap <NUM> and base <NUM> (e.g., blunt cannula, septa, and so forth) are still present but have been omitted from the drawings in order to illustrate more concisely operation of the infusion set described in greater detail below.

The flexible-hoop cap element <NUM> works in accordance with the principle that if opposite sides of a flexible-hoop are compressed, the two sides that are about <NUM> degrees (i.e., perpendicular) relative to the sides upon which the compression force is applied, will be moved apart by the compression force. In this example, the flexible-hoop cap element <NUM> will have an exemplary compression force applied to sides 102A, B and in doing so, sides 102C, D will be forced apart. The retention member <NUM> comprises at least the projections 104A, 104B, disposed on an inner surface of the sides 102C, D of the flexible-hoop cap element <NUM>. The projections can comprise any suitable shape, including the partial, contour shape of <FIG>, that can be used to capture and release the post <NUM> through the deflection of the sides 102C, D. In yet other examples, only one projection can be provided to capture the post <NUM>. Further, one or more elements of the set can comprise elements <NUM> to serve as guides for alignment and travel limits during the operation of the flexible-hoop cap element <NUM>.

An exemplary flexible-hoop cap element <NUM> can be circular, square, rectangular, hexagonal or any other polygonal shape. In one exemplary embodiment, the flexible-hoop is in the shape of a rectangle or hexagon. For purposes of this discussion, a rectangular shape will be used as an example. However, this example is not meant to be limiting, as any polygonal shape can be used, as discussed above.

In an exemplary operation of the flexible-hoop cap element <NUM>, the post <NUM> (not currently shown) is positioned in the center of the flexible-hoop cap element <NUM>. The retention member 104A, B interfaces with the undercut <NUM> on the post <NUM>, since each is attached to approximately the center of each of sides <NUM> C, D. As the user applies an inward force on the short sides 102A, B of the flexible-hoop cap element <NUM> along the force arrows A, B, the long sides 102C, D bow outward in the direction of force arrows C, D, moving the retention member 104A, B away from the post <NUM> and releasing the undercut <NUM>.

Various modifications and alterations can be made to the flexible-hoop cap element <NUM>. For example, the long sides 102C, D can be biased to bend in the desired direction. Further, the flexible-hoop cap element <NUM> can be weakened at the corners and/or center of the long sides 102C, D to help and control the bending. The flexible-hoop cap element <NUM> can also be made of one or multiple pieces. If the flexible-hoop cap element <NUM> is made of multiple pieces, flexibility can be imparted into in one or more of the separate pieces, hinges can be used where the pieces join, and/or a flexible joining material (e.g., an adhesive) can be used. The natural spring action of the material can also be used to keep the retention members 104A, B engaged with the post <NUM> when not activated, or additional springs can be added to facilitate the natural retaining force of the flexible-hoop cap element <NUM>. For example, a spring or springs can be provided to stretch across the flexible-hoop cap element <NUM> from the first long side 102C to the second long side 102D. Further, both short sides 102A, B of the flexible-hoop cap element <NUM> can move, or one side can be fixed to the cap <NUM>, with only one side permitted to move. Still further, the flexible-hoop cap element <NUM> does not have to form a complete hoop, but can be one-sided such that features of only one side (i.e., 104A) can be used to secure the cap.

<FIG>, as discussed above briefly in regard to <FIG>, illustrate a modification of the cap retention means <NUM> shown in <FIG>. <FIG> illustrate a bottom view of another exemplary cap retention means <NUM> that can be provided within cap <NUM> or in place of cap <NUM>. In <FIG>, the flexible-hoop cap element <NUM>, shown within the cap <NUM>, is in a relaxed state. This is the state of the cap retention means <NUM> prior to, or after attachment to the base <NUM>. In <FIG>, mutually applied forces, represented by arrows A, B, are applied to the flexible-hoop cap element <NUM> at sides 202A, B. According to the above-discussed principles of bending, the long sides 202C, D of the flexible-hoop cap element <NUM> bend outward in the direction of arrows C, D due to the applied forces. Note that in this example of the flexible-hoop cap element <NUM>, the sides 202C, D are biased outwardly.

The first and second flexible-hoop cap retention member 204A, B also moves outward with sides 202C, D. <FIG> illustrate simplified side views of the flexible hoop cap element <NUM> fitted over the base <NUM> of <FIG>. The first and second hoop-cap retention members 204A, B fit under the undercut <NUM> on the post <NUM>, thereby locking the flexible-hoop cap element <NUM> onto the base <NUM>. <FIG> illustrates the relationship between the first and second flexible-hoop cap retention member 204A, B and the undercut <NUM> on the post <NUM> when the sides 202A, B (see <FIG>) of the flexible-hoop cap element <NUM> have been pushed inwardly in the direction of arrows A, B (see <FIG>). Because of the omni-directional configuration of the first and second flexible-hoop cap retention member 204A, B and the post <NUM>, the flexible-hoop cap element <NUM> can be locked onto the base <NUM> in almost any direction. In yet another example illustrated in <FIG>, a modification to the embodiment of <FIG>, B and 21A can be provided, wherein the top of element <NUM> can be pressed downward in the center, thus causing the elements 204A, B to be pushed outward. In doing so, the contour of the disengagement shown in <FIG> would be substantially reversed, but still result in the release of the undercut <NUM> of the post <NUM>.

The flexible-hoop cap element <NUM>, <NUM> can also be fabricated with several cut-away, or weakened portions, to facilitate bending of the sides. In <FIG>, B, such exemplary portions are shown as weakened portions 106A-F, and can be provided and located to facilitate movement of the sides 102A-D, 202A-D, in the desired directions. A user therefore is required to apply a lesser force according to arrows A, B when putting the cap retention means <NUM>, <NUM> onto the base <NUM>, or removing the cap retention means <NUM>, <NUM> from the base <NUM>.

<FIG> illustrates a top view of another exemplary cap retention means <NUM>. The cap retention means comprises an open-ended "U-shaped" flexible-hoop cap element <NUM> and an extending wedge <NUM> that can be provided within cap <NUM> or in place of cap <NUM>. As shown in <FIG>, the U-shaped flexible-hoop cap element <NUM> comprises the sides 302A, C, D, and the retention members 304A, B, attached to inner surfaces substantially as described above. The remaining side of the cap element <NUM> is left open.

In operation, the sides 302C, D are flexed apart in the direction of arrows C, D, by the application of a user applied force in the direction of arrow A, which introduces the extending wedge <NUM> into the open end <NUM> of the U-shaped flexible-hoop cap element <NUM> in the direction of arrow B. Such movement of the cap element <NUM> results in the sides 302C, D being displaced outwardly by the incline of the wedge <NUM>, thereby releasing the post <NUM> (not currently shown) from the retention members 304A, B.

As with the other cap retention means discussed above, various modifications and alterations can be made to the cap retention means <NUM>. For example, the U-shaped flexible-hoop cap element <NUM> can be fixed to the cap <NUM> such that the extending wedge <NUM> is movable between a securing and releasing position, or the extending wedge <NUM> can be fixed to the cap <NUM> such that the U-shaped flexible-hoop cap element <NUM> is movable between a securing and releasing position. In still another example, both the extending wedge <NUM> and the U-shaped flexible-hoop cap element <NUM> can be made movable. Further, the extending wedge <NUM> can comprise one or more ramped slots (not shown) in the cap <NUM>, with posts on the U-shaped flexible-hoop cap for guidance through engagement with the slots, or using a similar but reversed arraignment.

The U-shaped flexible-hoop cap element <NUM> can be made of one piece or multiple pieces joined together. The extending wedge <NUM> can be made part of the U-shaped flexible hoop cap element <NUM> with a living hinge (not shown) to allow the extending wedge <NUM> to move. The U-shaped flexible-hoop cap element <NUM> can also have weakened areas to allow the deflection (as shown in the example of the flexible-hoop cap element <NUM>), and/or can have hinges to provide other desired flexibility. The extending wedge <NUM>, in relation to the U-shaped flexible-hoop cap element <NUM> and the sides 302A, C, D, of the U-shaped flexible-hoop cap element <NUM> can be self-sprung or can have external springs. In an exemplary operation, the extending wedge <NUM> is pressed into the opening <NUM>, and with the application of force applied in the directions indicated by arrows A and B, the sides 302C, D, are forced open in the direction of arrows C, D.

<FIG> illustrate side views of another exemplary cap retention means <NUM>. As shown in <FIG>, the cap retention means <NUM> comprises a dome-shaped flexible cap <NUM> that includes a first and second lever 118A, B with a circular detent, shoulder, or other similarly functioning retention means <NUM> all along the underside of the dome-shaped flexible cap <NUM> to engage the undercut <NUM> of a base wall <NUM> on the base <NUM>. In an exemplary embodiment, the base wall <NUM> can be substantially circular and extend upwardly from the base <NUM>. An upper surface of the base wall <NUM> can have the detent, shoulder, or other similarly functioning undercut means <NUM> to releasably capture the retention means <NUM> of the cap <NUM>. A top surface of the undercut means <NUM> can be contoured or rounded, as can be the lower surface of the retention means <NUM>, such that when contacting each other, each can be displaced slightly and slide over one another.

In an exemplary operation, the cap <NUM> can be pressed downward on the base <NUM> until the undercut means <NUM> is captured by the retention means <NUM>. When the user then pushes on the first and second lever 118A, B along the force arrows A, B, the retention means <NUM> moves away from the undercut <NUM> of base wall <NUM> in the direction of arrows C, D allowing the user to remove the dome-shaped flexible cap <NUM>. In the cap retention means <NUM>, the first and second levers 118A, B, along with the portion of the dome-shaped flexible cap <NUM> between the point of contact of the levers 118A, B and the dome-shaped flexible cap <NUM>, work as pivoting torsional springs. In doing so, a force pressing down, such as when the user pushes on the first and second lever 118A, B along the force arrows A, B, causes the dome-shaped flexible cap <NUM> to move away from the undercut <NUM>, as shown in <FIG>. The first and second levers 118A, B also provide a means for gripping the cap <NUM>.

<FIG> illustrate various top views of another exemplary cap retention means <NUM>.

In <FIG>, the cap retention means <NUM> comprises a rigid hoop <NUM>, a spring <NUM>, a first rigid hoop extension/retention member <NUM>, a second rigid hoop extension/retention member <NUM>, and guide members <NUM>. The rigid hoop <NUM> comprises a contoured, rigid hoop to encircle the post <NUM>, and comprises at least one guided side 120A and at least one user accessible side 120B. The user accessible side 120B is configured to allow the user to push the entire rigid hoop in the direction of arrow F of <FIG>, B.

Elements of the rigid hoop <NUM> extending from the side 120B flare slightly to surround the post <NUM>, and are guided by passage between a number of guide members <NUM>. The side 120B is also urged in an opposite direction by the spring <NUM> captured between the side 120B and the first rigid hoop extension/retention member <NUM>. On an opposite side of the post <NUM>, the rigid hoop <NUM> is narrowed to provide at least one shoulder, or other similarly functioning second rigid hoop extension/retention member <NUM> to releasably capture a notch, detent or shoulder of the post <NUM> of the cap <NUM>. The guided side 120A extends further, from the extension/retention member <NUM>, and is guided by passage between a number of further guide members <NUM>.

In such an arrangement, the spring <NUM> urges the rigid hoop <NUM> into a secured position, forcing the extension/retention member <NUM> to releasably capture the notch, detent or shoulder of the post <NUM> of the cap <NUM> as shown in <FIG>. By pushing the rigid hoop <NUM> inward, the extension/retention member <NUM> releases the notch, detent or shoulder of the post <NUM> of the cap <NUM> as shown in <FIG>.

For example, to place the cap <NUM> over the post <NUM> of the base <NUM>, the user pushes the second side 120B of the rigid hoop <NUM> toward the first rigid hoop extension/retention member <NUM> against the force of the spring <NUM>, slips the first side 120A of the rigid hoop <NUM> through the guide members <NUM>, and then lowers the cap <NUM> onto the base <NUM>. The user then releases the second side 120B of the rigid hoop <NUM>, such that the second rigid hoop extension/retention means <NUM> become lodged under the undercut <NUM> of the post <NUM>. The cap <NUM> is then locked onto the post <NUM> and base <NUM>. <FIG> illustrates the latched condition of the cap retention means <NUM>. <FIG> is a cross-sectional view of the cap retention means <NUM> as shown in <FIG>, and <FIG> is a cross-sectional view of the cap retention means <NUM> as shown in <FIG>.

To remove the cap <NUM>, the user applies a force in the direction of the arrow F as shown in <FIG> illustrates the unlatched condition of the cap retention means <NUM>. This pushes the second rigid hoop extension/retention member <NUM> out from under the undercut <NUM> of the post <NUM>, and the user can then lift the cap <NUM>. In alternative modifications to the cap retention means <NUM>, the spring <NUM> can be made a separate part or can be integral to the rigid hoop <NUM>. Further, the rigid hoop <NUM> can be fabricated to have other ribs for contacting the post <NUM> for stabilization, and can be continuous or can be open-sided like a "C" or "U" shape.

<FIG> is a bottom view of another exemplary cap retention means <NUM> in an unlatched condition, and <FIG> is a bottom view of the cap retention means <NUM> in a latched condition. In <FIG>, the cap retention means <NUM> comprises a first and second lever locking arm 130A, B and first and second pivots 132A, B. The first and second lever locking arms 130A, B each comprise an "L" shape and are linked at one end by a spring <NUM>. The first and second lever locking arms 130A, B and the first and second pivots 132A, B are located on the underside of the cap <NUM> that interfaces with the post <NUM> of base <NUM>. That is, each of the first and second lever locking arms 130A, B are rotatably secured to the cap <NUM> at the first and second pivots 132A, B. At opposite ends, at a point past the post <NUM>, each of the first and second lever locking arms 130A, B are elastically secured to each other using the spring <NUM>. In such an arrangement, the spring <NUM> urges the ends of the first and second lever locking arms 130A, B together into a secured position, forcing at least one portion of each locking arms 130A, B to releasably capture the notch, detent or shoulder of the post <NUM> of the cap <NUM> as shown in <FIG>. By pushing the locking arms 130A, B, in the direction of arrow A, the arms release the notch, detent or shoulder of the post <NUM> of the cap <NUM> as shown in <FIG>.

For example, to retain the cap <NUM> on the post <NUM> of base <NUM> (note that base <NUM> is not shown, only post <NUM>), the user pushes the first and second lever locking arms 130A, B in the direction of the force arrows A as shown in <FIG>. The first and second lever locking arms 130A, B then rotate in the direction of arrows B, causing the spring <NUM> to expand. Eventually, the first and second lower locking arms 130A, B, are spaced far enough apart such that the post <NUM> can be fitted between them. This is the unlatched condition shown in <FIG>. Once the cap <NUM> is in place, the user relaxes the force applied at A and the first and second lever locking arms 130A, B, move to their relaxed position (as shown in <FIG>) under the undercut <NUM> of the post <NUM>, thereby retaining the cap <NUM> onto the base <NUM>. Various modifications can be made to the first and second lever locking arms 130A, B, including the shape and number of the first and second lever locking arms 130A, B. For example, in yet other examples, there can be only one lever locking arm, if desired, or more than those shown.

<FIG> illustrate bottom views of an alternative example of the latching mechanism to connect a tubing set to a connection post assembly shown in <FIG>. <FIG>, as with <FIG>, show the bottom of the cap <NUM> and post <NUM> without including base <NUM> (to which post <NUM> would be attached) for purposes of clarity. The exemplary embodiment of <FIG> are substantially as described above in regard to <FIG>, except that the spring <NUM> is relocated to an opposite side of the post <NUM> to elastically connect the arms at a point at or near the right angle of each. However, in each example, the spring can be configured to exert either an expansive force between connection points, or a contracting force between connection points. Accordingly, in doing so, the spring <NUM> urges the connection points of the arms apart and into a secured position.

For example, the cap retention means <NUM> is shown in its relaxed state in <FIG>. The spring <NUM> pushes the first and second locking arms 130A, B about the first and second pivots <NUM> A, B such that a portion of the arms 130A, B latch under the undercut <NUM> of the post <NUM>. To remove the cap <NUM> from the base <NUM>, a force is applied in the direction of arrows A as shown in <FIG>, causing the first and second locking arms to swing in the direction of arrow B and out from undercut <NUM> of post <NUM>. The cap <NUM> is then free to be removed, or become disassociated with the base <NUM>.

<FIG> illustrates a cross-sectional view of another exemplary cap retention means <NUM>. The cap retention means <NUM> comprises the cap <NUM>, spring <NUM>, spring-urged retention member <NUM> and opposite facing lip <NUM>. The infusion set in this example does not include the post <NUM> with an undercut. Instead, a cap retaining wall <NUM> is attached in a circular (or other shape) fashion around the point where the catheter <NUM> enters the body of the user, and the spring retention member <NUM> fits against it to secure the cap <NUM> to the base <NUM>.

The cap retaining wall <NUM> can comprise an undercut <NUM> that interacts with both the spring retention means <NUM> and lip <NUM>. In an example, the cap retaining wall <NUM> can be substantially circular and extend upwardly from the base <NUM>. An upper surface of the cap retaining wall <NUM> can have the detent, shoulder, or other similarly functioning undercut means <NUM> to releasably capture the spring-urged retention member <NUM> and lip <NUM> of the cap <NUM>. A top surface of the undercut means <NUM> can be contoured, inclined or rounded, as can be the lower surface of spring-urged retention member <NUM> and lip <NUM>, such that when contacting each other, each can be displaced slightly and slide over one another.

As seen in <FIG>, the user places the cap <NUM>, having the lip <NUM> extending downward therefrom, against the cap retaining wall <NUM>, and the lip <NUM> which is attached to the cap <NUM>, interfaces via one or more inclined surfaces between each, to thereby engage with the undercut <NUM> of the cap retaining wall <NUM>. The user then presses the spring retention means <NUM> with a force applied in the direction of the arrow F, causing it, in this case, to move to the right. The user lowers the cap <NUM> fully down upon the cap retaining wall <NUM> and releases the spring retention means <NUM> causing it to lock into place under the undercut <NUM> of the cap <NUM>. In doing so, the cap <NUM> can be located in any position on the base <NUM>, so the cap retention means <NUM> is not limited in any one particular direction, presuming the cap <NUM> and cap retaining wall <NUM> are circular. Other shapes can be used, and the directional qualities will depend upon the particular shape in use.

<FIG> illustrates a side view of another exemplary cap retention means <NUM>. The cap retention means <NUM> comprises a cap <NUM>, spring <NUM>, and a lip <NUM>. The infusion set in this example also does not include the post <NUM> with an undercut <NUM>. Instead, as with the exemplary embodiment shown in <FIG>, the cap retaining wall <NUM> is attached in a circular (or other shape) fashion around the point where the catheter <NUM> enters the body of the user, and the lip <NUM> fits against it to secure the cap <NUM> to the base <NUM>.

As noted above, the cap retaining wall <NUM> can comprise an undercut <NUM> that interacts with a spring-urged retention lever <NUM>. In an example, the cap retaining wall <NUM> can be substantially circular and extend upwardly from the base <NUM>. An upper surface of the cap retaining wall <NUM> can have the detent, shoulder, or other similarly functioning undercut means <NUM> to releasably capture the spring-urged retention lever <NUM> and lip <NUM> of the cap <NUM>. A top surface of the undercut means <NUM> can be contoured, inclined or rounded, as can be the lower surface of spring-urged retention lever <NUM> and lip <NUM>, such that when contacting each other, each can be displaced slightly and slide over one another.

As shown in <FIG>, the user places the cap <NUM> against the cap retaining wall <NUM>, and the lip <NUM>, which is attached to the cap <NUM>, interfaces with the undercut <NUM> of the cap retaining wall <NUM>. The user then presses the spring retention lever <NUM> with a force applied in the direction of the arrow F, causing it, in this case, to move to the left against an elastic contracting force of the spring <NUM>. In this example, the lever moves back and forth without rotation (which is described in regard to another embodiment of the present invention below). The user lowers the cap <NUM> fully down upon the cap retaining wall <NUM> and releases the spring-urged retention lever <NUM>, causing it to lock into place under the undercut <NUM> of the cap <NUM>. The spring retention lever <NUM> can lock into the undercut <NUM> at any location of the cap retaining wall <NUM> so the cap retention means <NUM> is not limited in any one particular direction, presuming the cap <NUM> and cap retaining wall <NUM> are circular. Other shapes can be used, and the directional qualities will depend upon the particular shape in use.

Claim 1:
An infusion set (<NUM>, <NUM>, <NUM>, <NUM>) connecting apparatus, comprising:
a cap (<NUM>) having an alignment opening (<NUM>);
a base (<NUM>) having a post (<NUM>) with an outer circumference and an inner circumference securing a septum (<NUM>), configured to slidably engage the alignment opening of the cap and at least one mechanism (<NUM>) to secure the cap, the mechanism having at least one shouldered inner surface;
characterized by
a rotatable coupling member (<NUM>) having a cylinder (<NUM>) on the cap (<NUM>) and first and second base hooks (60A, 60B) on the base (<NUM>) that rotatably capture the cylinder (<NUM>); wherein the rotatable coupling member is configured to rotate the cap relative to the base.