Abstract:
A subcutaneous infusion set. The subcutaneous infusion set may include a base for providing an infusion path; a cannula connected to and extending away from the base; a connector removably attachable to the base; and a tubing affixed to the connector. The connector may be limitedly rotatable on the base when the connector is removably attached to the base. Also, a contiguous pass for passing fluids may be formed from the tubing to the cannula when the connector is removably attached to the base.

Description:
BACKGROUND 
   1. Field of the Invention 
   The present invention relates to infusion sets and, in particular, to disposable infusion sets having a soft catheter which is inserted into the skin for the subcutaneous delivery of a fluid to a patient. 
   2. Description of Related Art 
   Subcutaneous infusion sets are generally used by patients for delivering a fluid or drug to a subcutaneous location in the patient. While most infusion sets include a delivery tube that may be connected to an infusion pump or other fluid or drug delivering device, the delivery tubes of prior art infusion sets have been disadvantageous to patients for a variety of reasons. 
   Some infusion sets of the prior art include a base portion disposed on the skin of the 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. However, if the connector portion of the infusion set is rigidly attached to the base portion, the delivery tube may be oriented in a position that is undesirable or impractical for the patient. If 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 of the prior art have been proposed so that the connector portion and, thus, the delivery tube, may rotate freely about the base portion. While infusion sets of this type have allowed patients to freely position the orientation of the delivery tubes, freely rotating infusion sets have other 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. 
   What is needed is a subcutaneous infusion set that gives the patient the flexibility to adjust the location of the delivery tube without the disadvantages associated with delivery tubes that are free to rotate completely around the infusion site. 
   SUMMARY 
   It is an object of an embodiment of the present invention to provide an improved infusion set, which obviates for practical purposes, the above mentioned limitations. 
   According to an embodiment of the present invention, an infusion set may include a base for providing an infusion path; a cannula connected to and extending away from the base; a connector removably attachable to the base; and a tubing affixed to the connector. The connector may be limitedly rotatable to less than 360 degrees on the base when the connector is removably attached to the base. Also, a contiguous passage for passing fluids may be formed from the tubing to the cannula when the connector is removably attached to the base. 
   The base may include at least one barrier extending away from a surface of the base and the connector may include at least one stop extending away from a surface of the connector. The at least one barrier may be disposed on the base so that it restricts the movement of the at least one stop when the connector is rotated about the base. The connector may be limited to a rotation of 60 degrees, 90 degrees or 120 degrees when the connector may be removably attached to the base. 
   The infusion set may also include a hub removably affixable to the base; a needle attached to the hub, the needle being removably insertable into the cannula; and a cover for covering the needle. An adhesive pad may be affixed to the base. The cannula may extend through the adhesive pad. 
   According to another embodiment of the present invention, a method for using an infusion set may include positioning a base on an infusion site; positioning a connector onto the base, the connector including a delivery tubing; and adjusting a position of the delivery tubing. Adjusting the position of the delivery tubing may be limited to a range of less than 360 degrees. Also, adjusting the position of the delivery tubing may be limited to a range of 120 degrees, 90 degrees, 60 degrees or 30 degrees. 
   According to another embodiment of the present invention, a subcutaneous infusion set may include a base portion having a receiving area; a cannula affixed to the base portion; a connector portion for removable attachment to the base, the connector being received in the receiving area of the base portion; and a tubing affixed to the connector portion. An angular movement of the connector portion may be restricted by the base portion to less than 360 degrees and a fluid may pass from the tubing to the cannula when the connector is attached to the base. 
   The base portion may include at least one first member extending away from a surface of the base portion. The connector portion may include at least one second member extending away from a surface of the connector portion. 
   The at least one first member may be disposed on the base portion so that it restricts the movement of the at least one second member when the connector portion is rotated about the base portion. The connector portion may be limited to a rotation of 60 degrees, 90 degrees or 120 degrees when the connector is removably attached to the base portion. 
   The infusion set may also include a hub removably affixable to the base portion; a needle attached to the hub and a cover for covering the needle. The needle may be removably insertable into the cannula. Also, an adhesive pad may be affixed to the base. The cannula may extend through the adhesive pad. 
   Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, various features of embodiments of the invention. 

   
     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 a subcutaneous infusion set according to an embodiment of the present invention. 
       FIG. 2  shows a top view of a connector and a delivery tubing according to an embodiment of the present invention. 
       FIG. 3  shows a perspective view of a connector according to an embodiment of the present invention. 
       FIG. 4  shows a bottom view of a connector according to an embodiment of the present invention. 
       FIG. 5  shows a side view of a connector according to an embodiment of the present invention. 
       FIG. 6  shows another side view of a connector according to an embodiment of the present invention. 
       FIG. 7  shows a side cut-away view of a connector according to an embodiment of the present invention. 
       FIG. 8  shows an exploded view of a needle hub, a needle guard  24  and a base  26  according to an embodiment of the present invention. 
       FIG. 9  shows a cut-away view of a needle hub, a needle guard and a base according to an embodiment of the present invention. 
       FIG. 10  shows a blown-up view of a needle and cannula portion according to an embodiment of the present invention. 
   

   DETAILED DESCRIPTION 
   The following detailed description is of the best presently contemplated mode of implementing the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention. The scope of the invention is best defined by the appended claims. 
   As shown in the drawings for purposes of illustration, the invention is embodied in an infusion set for infusion of a liquid, such as medication, chemicals, enzymes, antigens, hormones, vitamins or the like, into a body of a user. Particular embodiments are directed towards use in humans; however, in alternative embodiments, the external infusion devices may be used in animals. 
     FIG. 1  shows a perspective view of a subcutaneous infusion set  10  according to an embodiment of the present invention. The subcutaneous infusion set  10  shown in  FIG. 1  may include, without limitation, a holding pad  20 , a needle hub  22 , a needle guard  24 , a base  26 , a connector  16  and a delivery tubing  18 . As will be explained in greater detail below, the subcutaneous infusion set  10  may be used by placing the holding pad  20  on the skin of a patient, removing the needle hub  22  and attaching the connector  16  to the base  26 . Fluids may be delivered to a patient through the delivery tubing  18 . 
   The subcutaneous infusion set  10  may be used in a variety of applications. For example, the subcutaneous infusion set  10  may be used for delivering a fluid to a subcutaneous location in a patient. According to an embodiment of the present invention, the subcutaneous infusion set  10  may be used to deliver insulin to a subcutaneous location in a diabetic patient. 
     FIG. 2  shows a top view of the connector  16  and the delivery tubing  18  according to an embodiment of the present invention. A first end  32  of the delivery tubing  18  may be connected to the connector  16 . The first end  32  of the delivery tubing  18  may be connected to the connector  16  in a permanent fashion or may be removable. Similarly, a second end  34  of the delivery tubing  18  may be connected to a fitting  30 . The second end  34  of the delivery tubing  18  may be connected to the fitting  30  in a permanent fashion or may be removable. 
   The delivery tubing  18  may be fabricated in a variety of sizes according to embodiments of the present invention. For example, according to an embodiment of the present invention, the delivery tubing  18  may be approximately 42 inches in length. The length of the delivery tubing  18  may be determined by the user and may be any length desired by the user. In addition, the delivery tubing  18  may be made out of a variety of materials that are common in the industry for catheter-type tubings. For example, the delivery tubing  18  may be made out of TEFLON, silicone rubber, polyurethane, polyethylene, synthetic rubber, or the like. 
   The fitting  30  to which the second end  34  of the delivery tubing  18  may connect may be any of a variety of fittings. For example, according to embodiments of the present invention, the fitting  30  may be a male fitting or a female fitting. Also, according to embodiments of the present invention, the fitting  30  may be implemented in a variety of configurations. For example, the fitting  30  may be implemented as a Luer fitting. Alternatively, the infusion set may use a fitting as shown and described in U.S. Pat. No. 6,585,695, which is herein incorporated by reference in its entirety. 
     FIG. 3  shows a perspective view of the connector  16  according to an embodiment of the present invention. As can be seen in  FIG. 3 , the connector  16  may include, without limitation, at least one flange  46  and at least one open-ended channel  40  adjacent the flange  46 . The at least one open-ended channel  40  allows the flange  46  to flex in a transverse direction, allowing the connector  16  to attach to the base  26  as will be explained greater detail below. The flange  46  may include a depression  42  which provides a region with which a patient or other user may grasp the connector  16 . As can also be seen in  FIG. 3 , the connector  16  may include a tubing receptacle  44  into which the delivery tubing  18  may be positioned. 
   According to embodiments of the present invention, the connector  16  may be made from a variety of materials. For example, the connector  16  may be made from PVC, polyurethane, polyethylene, polycarbonate, plastics or the like. Also, for example, the connector  16  may be made from a transparent, semi-transparent or an opaque material. 
     FIG. 4  shows a bottom view of the connector  16  according to an embodiment of the present invention. In the view of the connector  16  shown in  FIG. 4 , two open-ended channels  40  may be seen adjacent the flanges  46 . In  FIG. 4 , the flanges  46  are formed with depressions  42 . Also seen in  FIG. 4 , according to an embodiment of the present invention, is a chamber  50  which may be disposed adjacent the tubing receptacle  44  (not shown in  FIG. 4 ). The chamber  50  may provide a path through which fluid moving through the delivery tubing  18  passes as it makes its way into a subcutaneous location in a patient. Also shown in  FIG. 4  is a channel pin  52 . According to an embodiment of the present invention shown in  FIG. 4 , the channel pin  52  may be disposed in a substantially perpendicular position relative to the chamber  50  and may also be coupled to the chamber  50  so as to provide a contiguous path (or passage) for fluid received from the delivery tubing  18 . The channel pin  52  may also provide positioning assistance when mating the connector  16  to the base  26 . 
   Also shown in  FIG. 4  according to embodiments of the present invention are mounting hooks  54 . The mounting hooks  54  may be disposed on a side of the flange  46  that interfaces with the base  26 . Because the flanges  46  themselves are flexible, the mounting hooks  54  are movable with respect to the base  26  by depressing the flanges  46 . Thus, the mounting hooks  54  may be positioned underneath and removed from mounting grooves on the base  26  as will be explained in greater detail below. 
   Also shown in  FIG. 4  according to embodiments of the present invention are two stops  60 . The stops  60  may be used to limit the rotation of the connector  16  in conjunction with barriers on the base  26  as will be explained in greater detail below. According to the embodiment of the present invention shown in  FIG. 4 , the stops  60  may be disposed on opposite sides of the connector  16 . According to other embodiments of the present invention, the stops  60  may be disposed at various locations on the connector  16  and may be disposed adjacent other stops. 
     FIG. 5  shows a side view of the connector  16  according to an embodiment of the present invention. In the embodiment of the invention shown in  FIG. 5 , the relative locations of the open-ended channels  40 , the depressions  42 , the tubing receptacle  44  and the flanges  46  may be seen. Also, as shown in  FIG. 5 , the stops  60  may extend beyond a flat boundary of the connector  16 . 
     FIG. 6  shows another side view of the connector  16  according to an embodiment of the present invention. In  FIG. 6 , the stops  60  may be seen in their relative positions at distal ends of the connector  16 . According to embodiments of the present invention, the stops  60  may be disposed on a portion of the connector  16  that does not flex or flexes minimally when the flanges  46  are flexed. Thus, according to the embodiment of the invention of shown in  FIG. 6 , the stops  60  may remain in a relatively static position regardless of the position of the flanges  46 . 
     FIG. 7  shows a side cut-away view of the connector  16  according to an embodiment of the present invention. In  FIG. 7 , the chamber  50  is shown disposed in an anterior portion of the connector  16  and connecting to the channel pin  52 . The channel pin  52  may be used to complete the path for fluid traveling from the delivery tubing  18  into a cannula as will be explained in greater detail below. Also seen in  FIG. 7  according to an embodiment of the present invention is a stop  60  located at a distal end of the connector  16 . 
   An exploded view of the needle hub  22 , the needle guard  24  and the base  26  may be seen in  FIG. 8  according to an embodiment of the present invention. As can be seen in  FIG. 8 , a needle  80  may be attached to the needle hub  22 . The needle  80  may be used to guide a cannula  76  into a subcutaneous location in a patient. The needle  80  may be made from a variety of materials. For example, the needle  80  may be made from stainless steel or any of a variety of alloys, ceramics, plastics, glasses, or the like. Also, according to an embodiment of the present invention, the needle  80  may be made in a variety of sizes from as large as 18 gauge to as small as 33 gauge (or smaller). For example, according to an embodiment of the present invention, the needle  80  may be a 28 gauge needle. 
   According to embodiments of the present invention, a septum  74  may be disposed in the base  26  for providing a seal. The septum  74  may be made from a resilient material and may include an opening through which the needle  80  may be inserted. According to embodiments of the present invention, a cap  72  may be positioned on top of the septum  74  for providing a retaining function for the septum  74 . The needle  80  may be inserted through the septum  74  and through a needle guide  70  so that it is positioned within a lumen portion of the cannula  76 . In preferred embodiments, the septum is made from a silicone rubber. However, in alternative embodiments, the septum may be formed out of other elastomeric materials, such as rubber, bromobutyl rubber, synthetic rubber, or the like. 
   When the needle  80  is extended through the septum  74  and into the lumen of the cannula  76 , it may extend well beyond the holding pad  20 . The needle guard  24  may be provided to protect a user from accidental puncture by the extended needle  80 . Also, as can be seen in  FIG. 8 , according to an embodiment of the present invention, the holding pad  20  may be provided with adhesive protectors  78  if the holding pad  20  includes an adhesive for maintaining a position of the base  26  on a patient&#39;s skin. The adhesive protectors may be removed when the patient is ready to apply the base  26  and the holding pad  20  to the patient&#39;s skin. 
   The needle guard  24  may attach to the needle hub  22  to cover the needle  80  and to provide protection from accidental puncture by the needle  80 . Portions of the needle guard  24  may extend through apertures in the base  26  to engage the needle hub  22 . The needle guard  24  may attach to the needle hub  22  via friction fit, hooks, a locking mechanism or the like. 
   Also shown in  FIG. 8 , according to embodiments of the present invention, the base  26  may include barriers  82  and a mounting groove  84 . According to embodiments of the present invention, the barriers  82  may be used in conjunction with the stops  60  on the connector  16  to limit the angular or circular movement of the connector  16  while it is attached to the base. Also according to embodiments of the present invention, the mounting groove  84  may be used in conjunction with the mounting hooks  54  for mating the connector  16  to the base  26 . Thus, according to the embodiment of the invention shown in  FIG. 8 , the barriers  82  used in conjunction with the stops  60  on the connector  16  limit the angular or circular movement of the connector  16  while it is attached to the base while the mounting groove  84  used in conjunction with the mounting hooks  54  allow the connector  16  to mate with the base  26  in any orientation. 
   According to embodiments of the present invention, the base  26  may be made from a variety of materials. For example, the base  26  may be made from PVC, polyurethane, polyethylene, polycarbonate, plastics and the like. Also, for example, the base  26  may be made from a transparent, semi-transparent or an opaque material. 
     FIG. 9  shows a cut-away view of the needle hub  22 , a needle guard  24  and the base  26  according to an embodiment of the present invention. As can be seen in  FIG. 9 , the needle  80  may extend through the septum  74 , beyond the holding pad  20  and through the lumen of the cannula  76 . 
     FIG. 10  shows a blown-up view of the needle  80  and cannula  76  portion of  FIG. 9  according to an embodiment of the present invention. In  FIG. 10 , the needle  80  can be seen extending past the holding pad  20  and into and through the lumen of the cannula  76 . As can be seen in  FIG. 10  the needle  80  may extend through the lumen of the cannula  76  and terminate in a sharp, distal end disposed at least slightly beyond a distal end of the cannula  76 . 
   According to embodiments of the present invention, the cannula  76  may be fabricated from a soft, pliable material such as TEFLON (polytetrafluorethylene), silicone rubber, polyurethane, polyethylene, plastic, other materials coated with TEFLON or a TEFLON-like material, or the like. When the connector  16  is positioned onto the base  25 , the channel pin  52  may mate with the cannula  76  to provide a contiguous path for fluid delivery from the delivery tubing  18  to a subcutaneous location in the patient. 
   Thus, referring to  FIGS. 1 ,  2 ,  4  and  8 , in operation according to an embodiment of the present invention, a patient needing an infusion of a fluid, such as a diabetic needing an infusion of insulin, for example, may remove the needle guard  24  from the needle  80 , exposing the needle  80 . An infusion site may be chosen by the patient and the adhesive protector  78  may be removed from the holding pad  20 . The holding pad  20  may then be positioned on the skin of the patient at the chosen infusion site by inserting the needle  80  and the cannula  76  through the surface of the skin. The holding pad  20  is one example of means to positioning a base  26  on an infusion site of a user. The infusion set may be inserted into the skin by use of an insertion tool, such as that shown and described in U.S. Pat. No. 6,607,509, which is herein incorporated by reference in its entirety. 
   Once the needle the holding pad  20  has been positioned on the skin, the needle hub  22  and the needle  80  may be removed from the base  26 , leaving most of the cannula  76  at a subcutaneous position in the patient. The position of the holding pad  20  on the skin of the patient may be maintained by an adhesive on the surface of the holding pad  20  adjacent the skin. 
   Next the connector  16  may be positioned onto the base  26 . The patient may grasp the connector  16  at the depressions  42  and apply a force at those points, thereby flexing the flanges  46  toward a center portion of the connector  16 . In so doing, the mounting hooks  54 , being attached to the flanges  56 , will move in a similar direction. The patient may then position the connector  16  onto the base  26 . Because the depressed flanges  46  and, consequently, the mounting hooks  54  will be closer to a center portion of the connector  16  than they are in their resting position, the mounting hooks  54  may fit within an interior portion of the base  26  defined by the mounting groove  84 . The connector  16  may be pushed onto the base  26 , thereby disposing the mounting hooks  54  at a position within an area defined by and underneath the mounting groove  84 . The patient may then release the depressions  42  and the connector  16 . 
   When the patient releases the depressions  42  and the connector  16 , the flanges  46  and the mounting hooks  54  will move to their resting position. Thus, the mounting hooks will reside and be locked underneath the mounting groove  84 . The flanges  46  is one example of means for positioning the connector  16  onto the base  26 . 
   Once the connector  16  has been positioned on the base  26  in the manner just described, the patient may adjust the orientation of the connector  16  with respect to the base  26  in order to place the delivery tubing  18  at an optimum location. This may require the user to disconnect and reconnect the connector  16  to the base  26  to place the barriers  82  and stops  60  in the desired relative orientation within a selected region of allowed rotation. The orientation of the connector  16  with respect to the base  26  may be limited by the stops  60  and the barriers  82 . Although the mounting hooks  54  are free to rotate about the mounting groove  84 , the angular or circular movement of the connector  16  may be limited by the stops  60  and the barriers  82 . The barriers  84  prevent the connector  16  from rotating freely around the base by providing physical interference to the stops  60 . The disconnection and reconnection of the connector  16 , and the rotation of the connector  16  provide two examples of means for adjusting the position of the delivery tubing  18  for the user. 
   Thus, for example, according to an embodiment of the present invention, if the barriers  84  are spaced around a circumference of the base  26  at 60 degree intervals, the angular or circular movement of the connector  16  around the base  26  will be limited to 60 degrees. According to other embodiments of the present invention, the barriers  84  may be spaced around a circumference of the base  26  at a variety of intervals. For example, if the barriers  84  are spaced around a circumference of the base  26  at 90 degree intervals, the angular or circular movement of the connector  16  around the base  26  will be limited to 90 degrees. In preferred embodiments, there is at least one stop  60  and barrier  82  so that the rotation is limited to less than 360 degrees. However, in alternative embodiments, more stops and barriers may be used to limit rotation to, including but not limited to, 180 degrees, 120 degrees, 90 degrees, 75 degrees, 60 degrees, 45 degrees, 30 degrees, 15 degrees, or the like. In preferred embodiments, the minimum rotation is 1 degree or larger, such as but not limited to, 2 degrees, 5 degrees, 7.5 degrees, 10 degrees or the like. Theoretically, the stops and barriers could be positioned so that the connector  16  can be coupled to the base  26  with very little rotational movement. In a further alternative embodiment, the stops and barriers are shaped and configured to allow placement of the connector  16  in any orientation on the base  26  without rotational movement upon completion of the connection. Thus, in this embodiment the user can place the connection at any angle and have no relative movement once the connector  26  is locked to the base  26 . 
   Once the connector  16  has been oriented on the base  26  in a desired position, the fitting  30  may be attached to an infusion pump or other drug or fluid delivery system and infusion of a drug or fluid into the patient at the chosen subcutaneous location may commence. 
   Thus, advantages of embodiments of the present invention may be readily apparent. The connector  16  is not bound to a single position on the base  26 . If the delivery tubing  18  is not oriented in a desired or optimum position when the connector  16  is positioned on the base, the patient may rotate the connector  16  until the delivery tubing  18  is positioned at a desired orientation. At the same time, because the barriers  84  and the stops  60  limit the angular or circular movement of the connector  16 , the delivery tubing  18  avoids entanglement, twisting and kinking that may be associated with infusion sets having connectors whose rotational movement is not restricted. 
   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.