Abstract:
An infusion set for subcutaneous delivery of an infusant. The infusion set may include a base removably attachable to an infusion site and a connector temporarily lockable to the base. The connector can engage the base in a plurality of orientations. The connector locks into the base after at least partial rotation of the connector about the base. The connector may include flexible arms which unlock the connector from the base. The base includes a cannula for insertion through the infusion site. The connector includes a tubing for passing the infusant. The infusant is subcutaneously passable from the tubing through the cannula when the connector is attached to the base. The infusion set may also include a hub removably attachable to the base that includes a needle that extends through the base and the cannula and a guard removably attachable to the base opposite the hub for surrounding the needle.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a divisional of U.S. application Ser. No. 11/004,594, filed Dec. 3, 2004, entitled “Multi-Position Infusion Set Device and Process,” herein incorporated by reference in its entirety and is a basis for priority. This application is also a continuation-in-part of U.S. application Ser. No. 10/705,686, filed Nov. 10, 2003, entitled “Subcutaneous Infusion Set,” herein incorporated by reference in its entirety and is a basis for priority. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to infusion sets and, in particular, to infusion sets having a cannula which is inserted into the skin of a patient to facilitate the subcutaneous transfer of an infusant. 
     2. Description of Related Art 
     Infusion sets are typically used for delivering a fluid, drug or other infusant to a subcutaneous location in a patient. While most infusion sets include a delivery tube connected to an infusion pump or other fluid or drug delivering device, the configuration of some infusion sets have been disadvantageous to patients for a variety of reasons. 
     If an infusion set includes a base portion disposed on the skin of a patient and a connector portion that attaches to the base portion, a delivery tube may be attached to the connector portion. Thus, when the connector portion is attached to the base portion, the delivery tube may be connected to an infusion pump or other device for fluid delivery, permitting the patient to administer the desired or necessary infusant. However, if the connector portion of the infusion set is positioned in such a manner that the delivery tube is in a position that is undesirable or impractical for the patient, the patient is resigned to removing the base portion from the patient&#39;s skin and inserting a new infusion set base, since the old one cannot be safely reused. It is not normally possible to re-orient the base portion because re-orienting the base portion typically includes re-inserting a needle into the skin. Also, re-orienting the base portion can be discomforting, painful or could lead to infection and thus is undesirable for the patient. 
     Some infusion sets are configured so that the connector portion and, thus, the delivery tube, may rotate freely about the base portion. Freely rotating infusion sets have disadvantages. Generally, too much movement of the delivery tube is undesirable. For example, because the delivery tube is typically delivering a fluid or some type of drug or infusant to a patient, it is necessary that the fluid path remain unobstructed. If the delivery tube is permitted to rotate freely around the base portion of the infusion set, the delivery tube may be subject to entanglement, twisting, kinking or the like, interrupting the infusion process. In addition, a freely rotating delivery tube can, at times, appear or feel to the patient to be disconnected from the patient and, thus, may result in a sense of insecurity for the patient. 
     The needs of patients who rely on infusion sets are numerous. For example, patients need infusion sets that require a positive action for releasing a connector from a base—infusion sets that release inadvertently are inconvenient and worrisome. In addition, while it is desirable that the size of the infusion set be minimized, it is also desirable that a patient be able to hold on to the infusion set and that protective pieces of the infusion set remain in place when the infusion set is in storage. Moreover, patients desire the flexibility to attach a connector to a base in multiple positions but also a connector that maintains the position of a delivery tube so that the aforementioned problems of a freely rotating tube are avoided. 
     SUMMARY OF THE DISCLOSURE 
     According to an embodiment of the present invention, an infusion set may include a base removably attachable to an infusion site for providing a subcutaneous path for an infusant and a connector temporarily lockable to the base. The base may be engagable by the connector in a plurality of orientations. In addition, the base may include a plurality of apertures and the connector may include a plurality of tabs insertable into the plurality of apertures. 
     The connector may be at least partially rotatable about the base and at least one tab of the plurality of tabs may be rotatable from a position within at least one aperture of the plurality of apertures to a locked position. The base may include at least one abutment for locking at least one tab of the plurality of tabs into a position. The connector may include a plurality of arms and each arm of the plurality of arms may be fixedly attached to a tab of the plurality of tabs. The plurality of arms may be flexible. Each arm of the plurality of arms may be flexed to remove a tab of the plurality of tabs from a locked position to an unlocked position. The connector may be removable from the base by simultaneously flexing the plurality of arms. 
     According to an embodiment of the present invention, the base may include a cannula for insertion through the infusion site. The connector may include a tubing for passing the infusant. The infusant may be subcutaneously passable from the tubing through the cannula when the connector is attached to the base. 
     Embodiments of the invention may include a hub removably attachable to the base. The hub may include a needle extending through the base and through the cannula. Embodiments of the invention may also include a guard removably attachable to the base opposite the hub for surrounding the needle. The needle may be subcutaneously insertable into the infusion site for subcutaneously positioning the cannula. 
     The base may include an adhesive pad for attaching to the infusion site. The infusion site may be the skin of a patient. 
     According to an embodiment of the present invention, a method for delivering an infusant may include positioning a base at an infusion site for providing a subcutaneous path for the infusant; engaging the base with a connector, the connector being temporarily lockable to the base; and rotating, at least partially, the connector about the base until the connector temporarily locks to the base. The base may be engagable by the connector in a plurality of orientations. The base may include a plurality of apertures and the connector may include a plurality of tabs. The method may further include inserting the plurality of tabs into the plurality of apertures. The method may further include providing at least one abutment on the base for locking at least one tab of the plurality of tabs in the locked position and may further include providing a plurality of arms on the connector. Each arm of the plurality of arms may be fixedly attached to a tab of the plurality of tabs. The plurality of arms may be flexible and the method may further include flexing each arm of the plurality of arms to remove a tab of the plurality of tabs from a locked position to an unlocked position. The method may further include simultaneously flexing the plurality of arms to remove the connector from the base and inserting a cannula connected to the base through the infusion site. 
     The method may further include providing a hub removably attachable to the base, the hub including a needle extending through the base and through the cannula; providing a guard removably attachable to the base opposite the hub for surrounding the needle; and subcutaneously inserting the needle into the infusion site for subcutaneously positioning the cannula. 
     According to an embodiment of the present invention, an infusion set may include a base removably attachable to an infusion site for providing a subcutaneous path for an infusant; a connector removably attachable to the base; and a locking mechanism for temporarily locking the connector to the base. The base may be engagable by the connector in a plurality of orientations. The base may include a plurality of apertures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A detailed description of embodiments of the invention will be made with reference to the accompanying drawings, wherein like numerals designate corresponding parts in the several figures. 
         FIG. 1  shows a perspective view of an infusion set according to an embodiment of the present invention. 
         FIG. 2  shows a perspective view of an infusion set according to another embodiment of the present invention. 
         FIG. 3  shows a top-down view of a connector in an unlocked position on a base according to an embodiment of the present invention. 
         FIG. 4  shows a perspective cutaway view of a connector and a base according to an embodiment of the present invention. 
         FIG. 5  shows a perspective cutaway view of a connector as it engages a base according to an embodiment of the present invention. 
         FIG. 6  shows a top-down, skeletal view of a connector as it engages a base in an unlocked position according to an embodiment of the present invention. 
         FIG. 7  shows a top-down, skeletal version of a connector as it engages a base in a locked position according to an embodiment of the present invention. 
         FIG. 8  shows an exploded, cutaway view of an infusion set according to an embodiment of the present invention. 
         FIG. 9  shows a cutaway view of a hub and a guard removably attached to a base according to an embodiment of the present invention. 
         FIG. 10  shows another embodiment of a hub according to an embodiment of the present invention. 
         FIG. 11  shows another embodiment of a hub according to an embodiment of the present invention. 
         FIG. 12  shows an embodiment of a guard according to an embodiment of the present invention. 
         FIG. 13  shows an embodiment of a guard tab interfacing with a base in an unlocked position according to an embodiment of the present invention. 
         FIG. 14  shows an embodiment of a guard tab interfacing with a base in a locked position according to an embodiment of the present invention. 
         FIG. 15  shows another embodiment of a guard tab interfacing with a base in an unlocked position according to an embodiment of the present invention. 
         FIG. 16  shows another embodiment of a guard tab interfacing with a base in a locked position according to an embodiment of the present invention. 
         FIG. 17  shows another embodiment of a guard tab interfacing with a base in an unlocked position according to an embodiment of the present invention. 
         FIG. 18  shows another embodiment of a guard tab interfacing with a base in a locked position according to an embodiment of the present invention. 
         FIG. 19  shows perspective view of another base according to an embodiment of the present invention. 
         FIG. 20  shows a perspective view of another connector according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following description of preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the preferred embodiments of the present invention. 
     Embodiments of the present invention relate to infusions sets and processes of using and making same. Such infusion sets may be employed to transfer a medication, an infusant and the like between a reservoir and a patient. For example, an infusion set may be used by connecting the infusion set to an insulin infusion pump to a diabetic patient. Other embodiments may be employed for other medical or infusion applications or procedures. 
       FIG. 1  shows an infusion set  10  according to an embodiment of the present invention. The embodiment of the infusion set  10  shown in  FIG. 1  includes, but is not limited to, a connector  12  and a base  14 . The connector  12  and the base  14  in the embodiment of the invention shown in  FIG. 1  are configured such that the connector  12  is removably attachable to the base  14 . 
     The connector  12  may include, without limitation, two or more arms  16  that may be used to facilitate connecting and/or removing the connector  12  to the base  14 . In addition, the arms  16  may include a cutout, depression or surface  15  that may aid a user or patient in gripping the connector  12 . The connector  12  may also include a port  20  to which is connected a tubing (not shown) for passing a fluid, medication or other infusant from an infusion pump, reservoir or the like through the infusion set to a subcutaneous location in a patient. 
     The base  14  may include a plurality of grooves, cutouts, depressions, spacings, apertures and the like to facilitate a connection between the connector  12  and the base  14  as will be explained in greater detail below. For example, as can be seen in the embodiment of the invention shown in  FIG. 1 , the base  14  includes an inner depression  18  for accepting a tab or other extended member disposed on the connector  12  as well as an aperture  22  for accepting a tab or other extended member disposed on a hub, as will be explained in greater detail below. 
     In the embodiment of the invention shown in  FIG. 1 , the connector  12  and the base  14  are of a substantially circular disc shape. However, the connector  12  and the base  14  need not be circular and could be designed to be any shape convenient to or desired by a patient, healthcare professional or other user of the infusion set. In addition, the connector  12  and the base  14  may be designed in a variety of sizes. For example, according to an embodiment of the present invention, the connector  12  and the base  14  may be designed small enough to be unobtrusive to a patient when wearing the infusion set  10  but large enough so that the patient can easily hold onto the infusion set  10  when applying the infusion set  10  to or removing the infusion set  10  from the patient&#39;s skin. For example, the connector and base may have a circular disc shape with a diameter in the range of about 0.5 inches (1.27 cm.) to about 1.25 inches (3.175 cm.). 
     Also, according to an embodiment of the present invention, the base  14  may be designed so that it can be affixed to a patient&#39;s skin. For example, the base  14  may include an adhesive applied to a bottom portion of the base  14 , i.e., the portion of the base  14  that comes into contact with a patient&#39;s skin, so that the base  14  adheres to the patient&#39;s skin when applied. According to another embodiment of the present invention, the base  14  may be supplied with an adhesive pad attached to a portion of the base  14 , such as a bottom portion, for example, which may adhere to the patient&#39;s skin when applied. 
       FIG. 2  shows an infusion set  30  according to another embodiment of the present invention. The infusion set  30  shown in  FIG. 2  includes, without limitation, a hub  32 , a base  14  and a guard  34 . Whereas the embodiment of the infusion set shown in  FIG. 1  may be used during operation with a patient, the embodiment of the invention shown in  FIG. 2  may be used during storage. As will be explained in greater detail below, the hub  32  affixes to a top or first side of the base  14  via a hub aperture  38 . In addition, the guard  34  attaches to a bottom or second side of the base  14  via the guard apertures  40 . The hub  32  may be used to cover the base  14  and to facilitate application of the base  14  onto the skin of a patient. The guard  34  may be used as a protective element to cover a needle (not shown) or other protrusion that may extend through the bottom of the base  14 . 
     According to an embodiment of the present invention, the base  14  may be designed in a variety of ways. For example, the base  14  may be designed with sufficient size and shape so that it is manageable, for example, easy to grip and maneuver, for a patient or other user when applying the base  14  to a patient&#39;s skin. According to an embodiment of the present invention, the base  14  may be designed large enough so that a patient may secure the base  14  with his or her fingers when removing the hub  32  from the base  14 . 
     The embodiments of the infusion sets shown in  FIGS. 1 and 2  may be made from a variety of materials. For example, according to embodiments of the present invention, the connector  12 , base  14 , hub  32  and guard  34  of the infusions sets shown in  FIGS. 1 and 2  may be made from plastics, such as PVC, polypropylene, polycarbonate and the like, for example, suitable rubbers, polymers, other synthetic materials and the like or combinations of two or more of these materials used together on a single part utilizing processes such as over molding or two-shot molding. 
       FIG. 3  shows a top down view of the connector  12  as it rests in an unlocked position on the base  14  according to an embodiment of the present invention. As can be seen in the embodiment of the invention shown in  FIG. 3 , the illustrated connector  12  includes inner tabs  42  fixedly attached or otherwise extending in a cantilevered fashion from the arms  16 . Outer tabs  44  extend, in a cantilevered fashion, from a portion of the connector  12  where the arms  16  extend from the body of the connector  12 . The inner tabs  42  and the outer tabs  44  are used to align the connector  12  with the base  44  and lock the connector  12  into place, thereby maintaining the position of the connector  12  with respect to the base  14  as will be explained in greater detail below. 
       FIG. 4  shows a prospective cutaway view of the connector  12  and the base  14  according to an embodiment of the present invention. As shown in  FIG. 4 , the inner tabs  42  extend away from the arms  16 . When the connector  12  engages the base  14 , an inner tab  42  on the connector  12  may be positioned in an inner depression  18  in the base  14 . The depression  18  may be sized liberally, for example, larger than the size of the inner tab  42 , so that the inner tab  42  may be easily positioned within it without having to depress the arms  16  on the connector  12 . 
     Also shown in  FIG. 4  is a connector duct  46  in a centrally located projection  17  of the connector  12  and a base duct  48  in the base  14 . The base duct  48  has a flared or enlarged diameter open-facing toward the connector  12 . The connector duct  46  is contiguous with the port  20  (not shown in  FIG. 4 ) and, thus, will pass a fluid, medicant or other infusant when the infusant passes through a tubing into the port  20 . When the connector  12  is engaged with the base  14 , the connector duct  46  in the projection  17  of the connector  12  extends at least partially into the enlarged or flared end of the base duct  48  to interface with the base duct  48  such that fluid may pass from the connector  12  to and through the base  14 . A subcutaneous cannula or catheter (not shown in  FIG. 4 ) may be affixed to the base duct  48  for passing the fluid into the body of a patient. 
       FIG. 5  shows a prospective cutaway view of the connector  12  and the base  14  when the connector  12  is engaged to the base  14  according to an embodiment of the present invention. In  FIG. 5 , the inner tabs  42  can be seen extending away from the arms  16  and positioned in the depression  18 . Moreover, the connector duct  46  can be seen engaging the base duct  48 . In  FIG. 5 , the connector  12  has not been locked onto the base  14  and, thus may be freely removable from the base  14 . 
       FIG. 6  shows a top down, skeletal view of the connector  12  as it engages the base  13  in an unlocked position according to an embodiment of the present invention. As can be seen in the embodiment of the invention shown in  FIG. 6 , the inner tabs  42  are positioned in the inner depressions  18 . In the embodiment of the invention shown in  FIG. 6 , the connector  12  has two arms  16  and two inner tabs  42 . However, the connector  12  may include more than two arms  16  and more than two inner tabs  42 . In addition, the base  14  in the embodiment of the invention shown in  FIG. 6  includes four inner depressions  18 , despite the fact that the connector  12  includes only two inner tabs  42  in the embodiment of the invention shown in  FIG. 6 . The presence of a plurality of inner depressions  18  allows the connector  12  to engage the base  14  in a plurality of positions. Any number of inner depressions  18  may be configured in the base  14 . For example, according to embodiments of the present invention, the base  14  may be configured with two, three, four, five, six or more depressions. 
     Also shown in the embodiment of the invention of  FIG. 6  are outer tabs  44  and outer depressions  19 . Much in the same way that the inner tabs  42  are positioned in the inner depressions  18  when the connector  12  engages the base  14 , the outer tabs  44  are positioned in the outer depressions  19  when the connector  12  engages the base  14 . Both the inner tabs  42  and the outer tabs  44  may be used to guide the connector  12  around the base  14  and to lock the connector  12  to the base  14  as will be explained in greater detail below. 
       FIG. 7  shows a top down, skeletal version of the connector  12  engaged with the base  14  in a locked position according to an embodiment of the present invention. In the embodiment of the invention shown in  FIG. 7 , the connector  12  has been rotated from its unlocked position, and, thus, as can be seen in  FIG. 7 , the inner tabs  42  are no longer disposed in the inner depressions  18 . Rather, as the connector  12  has been rotated about the base  13 , the inner tab  42  travels radially along the cam  50  and is forced toward the center of the base  14  due to the flexibility of the arm  16 . When the connector  12  has been rotated about the base  14  far enough so that the inner tab  42  of the connector  12  reaches the locking depression  52 , the inner tab  42  “snaps” into the locking depression  52  of the base  14 . An inner underportion  54  is configured such that a portion of the inner tab  42  resides underneath the inner underportion  54 , thereby preventing axial movement of the connector  12 . The inner tab  42  of the connector  12  is prevented from additional rotation by an inner stop surface  58  and by a proximate end of the cam  50  of the base  14 . 
     Also as the connector  12  is being rotated about the base  14 , the outer tab  44  of the connector  12  moves radially along with the connector and is prevented from additional rotation by the second stop surface  60  of the base  14 . An outer underportion  56  is configured such that a portion of the outer tab  44  resides underneath the outer underportion  56 , thereby preventing axial movement of the connector  12  in the direction of the outer underportion  56  and providing a redundant function of preventing axial movement in addition to that afforded by positioning the inner tab  42  under the inner underportion  54 . 
     Thus, as can be seen in  FIG. 7 , the connector  12  is in a locked position with respect to the base  14  in a number of respects. The inner tab  42  of the connector  12  is precluded from rotation relative to the base  14  when disposed in the locking depression  52  of the base  14  due to the barriers provided by the cam  50  and the first stop surface  58  of the base  14 . Likewise, the outer tab  44  of the connector  12  is precluded from rotation (in the embodiment of the invention shown in  FIG. 7 , in the clockwise direction) by the second stop surface  60 . Additionally, both the inner tab  42  and the outer tab  44  of the connector  12  are prevented from moving axially relative to the base  14  due to the underportions  54  and  56 , respectively. Because a portion of the inner tab  42  and the outer tab  44  of the connector  12  reside under the inner underportion  54  and the outer underportion  56 , respectively, of the base  14 , in that state the connector  12  is effectively precluded from moving away from the base  14 . Thus, depression of only one arm  16  is ineffective to remove the connector  12  from the base  14 . 
     In order to remove the connector  12  from the base  14 , both arms  16  of the connector  12  may be manually depressed, thereby positioning the inner tabs  42  of the connector  12  away from the locking depressions  52  of the base  14  and removing a portion of the inner tabs  42  from the inner underportions  54  of the base  14 . Once the inner tabs  42  have been freed from the locking position due to depression of the arms  16 , the connector  12  may be rotated in a direction opposite that used to place the connector  12  in a locking position (in the case of the embodiment of the invention shown in  FIG. 7 , in a counterclockwise direction). In the embodiment of the invention shown in  FIG. 7 , both arms  16  must be depressed in order to free the inner tabs  42  of the connector  12  from the locking depressions  52  of the base  14 . When, after rotation, the inner tabs  42  of the connector  12  reach the inner depression  18  of the base  14  and the outer tabs  44  of the connector  12  reach the outer depressions  19  of the base  14 , the connector  12  may be removed from the base  14 . 
       FIG. 8  shows an exploded, cutaway view of the infusion set  30  according to an embodiment of the present invention. In the embodiment of the invention shown in  FIG. 8 , the hub  32  includes generally rigid hub tabs  61  that have enough flexibility to permit the hub  32  to be removably attached to the base  14  via base apertures  62 . Similarly, the guard  34  includes generally rigid guard tabs  64  that have enough flexibility to permit the guard  34  to be removably attached to the base  14  via guard depressions  66 . As can also be seen in  FIG. 8 , the hub  32  may include a hub chamber  69  in which a needle  65  may be affixed. The needle may extend through the base duct  68  and into and through a cannula (not shown) affixed to the base  14  at the opening of the base duct  68 . The guard  34  may afford protection from the needle. 
       FIG. 9  shows a cutaway view of the hub  32  and guard  34  removably attached to the base  14  according to an embodiment of the present invention. As stated previously, this configuration may be used for storage of the device until a patient is ready to affix the base  14  to the patient&#39;s skin. It can be seen in  FIG. 9  that the hub tabs  61  have been inserted into the base apertures  62  and are maintained in their position via lips  63  that extend into the base apertures  62 . Likewise, the guard tabs  64  have been extended into the guard depressions  66  in the base  14 . Both the hub  32  and the guard  34  may be removed from the base  14  by squeezing the body of the hub  32  and the guard  34  in an area close to their respective tabs and separating the hub  32  and the guard  34  from the base  14 . 
     The hub  32  and the guard  34  may also be used together after a patient has positioned the base  14  onto his or her skin. For example, a patient may insert a cannula attached to the base  14  subcutaneously by removing the guard  34  and pushing the needle  65  and cannula into the skin by forcing the hub  32  and the base  14  onto the skin surface while the hub  32  remains affixed to the base  14 . However, after subcutaneous insertion of the cannula, the hub  32  may be removed from the base  14 , thereby exposing the needle  65  attached to the hub  32 . By including apertures (not shown) on the hub  32  configured to accept the guard tabs  64 , the guard  34  may be positioned over the needle  65  attached to the hub  32  to protect the patient or anyone else from the needle  65  until the hub  32  can be disposed. 
       FIG. 10  shows another embodiment of a hub  70  according to an embodiment of the present invention. The embodiment of the hub  70  shown in  FIG. 10 , includes, without limitation, a hub arm  72 , a hub tab  74 , a hub extension  76  and hub body  78 . In  FIG. 10 , the hub arm  72  has been configured for flexibility, providing adequate movement of the hub tab  74  and allowing for relatively easy application and removal of the hub  70  to a base, such as base  14  described above. In addition, one or more hub tabs  74  may be positioned at the end of a hub arm  72  to lock the hub  70  to a base. The hub extension  76  may be designed with sufficient length to allow a user to hold onto the hub  70  with one hand when using the other hand to remove an insertion tool that may be used with the device or as an aid in positioning the device onto the skin. The hub body  78  may be designed of sufficient size and geometry to allow a user to readily grip and hold onto it, for example, as between a thumb and a forefinger. For example, in the embodiment of the invention shown in  FIG. 10 , the hub body  78  includes grooves  79  that provide additional friction to a user when holding onto the hub  70 . 
       FIG. 11  shows another embodiment of a hub  80  according to an embodiment of the present invention. In the embodiment of the invention shown in  FIG. 11 , the hub  80  includes, without limitation, a hub arm  82 , a hub extension  88  and a hub body  90 . The hub arm  82  may include one or more hub tabs  84  and a wing  86 . The hub tab  84  may be used to lock the hub  80  into a base, such as base  14  described above. The wing  86  may be used to provide additional leverage for a user when inserting the hub  80  onto a base or removing the hub  80  from a base. As can be seen in  FIG. 11 , the hub arm  82  has been designed to be flexible to allow a user to perform these operations. The hub extension  88  may be designed with sufficient length to allow a user to hold onto the hub  80  when positioning the hub  80  in a base onto the user&#39;s skin, for example, with an insertion tool. The hub body  90  may be designed with sufficient size and geometry to allow a user to readily grip and hold onto the hub  80 . For example, in the embodiment of the invention shown in  FIG. 11 , the hub body  90  includes hub flanges  92  with which a user may grab the hub  80 , such as, for example, between a thumb and a forefinger. 
       FIG. 12  shows an embodiment of a guard  100  according to an embodiment of the present invention. In the embodiment of the invention shown in  FIG. 12 , the guard  100  may include, without limitation, a body  102 , one or more slots  104  and one or more tabs  106 . The body  102  may be designed with sufficient size and geometry to enclose a needle or other protrusion which may be extending away from a base or other part of the device. For example, in the embodiment of the invention shown in  FIG. 12 , the body  102  is substantially cylindrical and has a slight taper. Generally rigid tabs  106  at one end of the body  102  have sufficient flexibility to allow the guard  100  to be removably affixed onto a base or hub as the case may be. The slot  104  facilitates manual “squeezing” of the body  102 , thereby making it easier for a user to insert or remove the tabs  106  from a body or a hub. 
       FIG. 13  shows an embodiment of a guard tab  106  interfacing with a base  14  in an unlocked position according to an embodiment of the present invention. In the embodiment of the invention shown in  FIG. 13 , a guard tab  106  has been inserted into a tab opening  113  on the base  14 . The tab opening  113  has been designed for easy insertion of the guard tab  106 . The base  14  also includes an underportion  114  which, when the guard tab  106  is rotated away from the tab opening  113 , will be positioned underneath a portion of the guard tab  106  and will prevent the guard from being removed from the base. 
       FIG. 14  shows the guard tab  106  of  FIG. 13  in a locked position according to an embodiment of the present invention. In  FIG. 14 , the guard tab  106  has been rotated over the underportion  114  in the base  14  such that a face of the guard tab  106  engages an edge of the underportion  114 . This configuration is possible because the surface of the underportion  114  in the base  14  is lower than the base surface  116 . To remove the guard from the base  14  in this embodiment, the guard tab  106  may be rotated toward the tab opening  113 , away from the underportion  114  so that a user may pull the guard away from the base  14 . 
       FIG. 15  shows a guard tab engaging a base according to an embodiment of the present invention. In  FIG. 15 , the guard tab  106  is positioned in the tab opening  113  of the base  14 . In  FIG. 15 , the guard tab  106  is in an unlocked position in the base  14 . In  FIG. 16 , the guard tab  106  has been rotated about the base surface  124  so that the face of the guard tab  106  rests on an edge of the base surface  124 . In this position, the guard tab  106  is locked into the base  14 . In the embodiment of the invention shown in  FIG. 15  and  FIG. 16 , the base  14  does not include an underportion and, consequently, the base  14  serves as the mechanism preventing the guard tab  106  from being removed from the base  14 . 
       FIGS. 17 and 18  show a guard tab  106  in locked and unlocked positions, respectively, on a base  14 . The guard tab  106  may be rotated from the guard depression  133  so that a face of the guard tab  106  rests on an edge of the base surface  124 . In the embodiment of the invention shown in  FIGS. 17 and 18 , a protrusion  135  on the base surface  124  extends away from the base surface  124  into the space through which the guard tab  106  rotates, requiring an additional active movement by the user, such as, for example, a manual “squeezing” of the guard to move the guard tab  132  from a locked position to an unlocked position and vice versa. 
       FIG. 19  shows a base  14  according to an embodiment of the present invention. In  FIG. 19 , the base  14  includes, without limitation, a rim  142 , the outside of which is substantially smooth. The rim  142  shown in  FIG. 19  is advantageous in that, when the base  14  is positioned on a user&#39;s or patient&#39;s skin, the smooth outside portion of the rim  142  may minimize the snagging or catching of clothing and the like. 
       FIG. 20  shows a connector  12  suitable for use with a base such as the base  14  shown in  FIG. 19  according to an embodiment of the present invention. In  FIG. 20 , the connector  12  includes flexible tabs  152  and static tabs  154 , all of which may be insertable into depressions  144  of the base  14  shown in  FIG. 19 . Thus, the connector  12  may be positioned onto the base  14  in a plurality of orientations, but, when the connector  12  is rotated such that the flexible tabs  152  and the static tabs  154  are positioned under base edges  146  of the base  14 , the connector  12  will be locked onto the base  14 . 
     The flexible tabs  152  and the static tabs  154  may be designed in a variety of ways. For example, in the embodiment of the invention shown in  FIG. 20 , the flexible tabs  152  have been designed with corners to facilitate locking of the flexible tabs  152  with the base edges  146 . However, because the flexible tabs  152  are moveable due to their attachment to the arms of the connector, insertion and removal of the flexible tabs  152  from the base edges  146  is still possible via a positive action by the user. The static tabs  154 , on the other hand, are generally not moveable by a user in the embodiment of the invention shown in  FIG. 20  and, thus, have been designed with more rounded features to ease engagement with the base edges  146 . 
     While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that the invention is not limited to the particular embodiments shown and described and that changes and modifications may be made without departing from the spirit and scope of the appended claims.