Abstract:
A dual insertion set includes a base, an infusion portion, a sensor portion, and at least one piercing member. The base is adapted to secure the dual insertion set to the skin of a patient. The infusion portion includes a cannula for supplying a fluid to a placement site. The cannula is coupled to and extends from the base and has at least one lumen with a distal end for fluid communication with the placement site. The cannula has at least one port structure formed near another end of the lumen opposite the distal end. The sensor portion includes a sensor coupled to and extending from the base having at least one sensor electrode formed on a substrate. The sensor is for determining a body characteristic of the patient at the placement site. The at least one piercing member is coupled to and extends from the base to facilitate insertion of the cannula and the sensor.

Description:
RELATED APPLICATIONS  
       [0001]     This application claims the benefit of prior filed U.S. Provisional Application Ser. No. 60/678,861, filed May 6, 2005. 
     
    
     FIELD OF THE INVENTION  
       [0002]     Embodiments of the invention relate to improved sensor and infusion devices with improved placement aspects and, more particularly, to devices and methods for placing a sensor at a selected insertion site within the body of a patient, in addition to placing an infusion set with a catheter for delivery of selected fluids.  
       BACKGROUND OF THE INVENTION  
       [0003]     Insulin must be provided to people with Type 1 and many with Type 2 diabetes. Traditionally, since it cannot be taken orally, insulin has been injected with a syringe. More recently, use of external infusion pump therapy has been increasing, especially for delivering insulin for diabetics using devices worn on a belt, in a pocket, or the like, with the insulin delivered via a catheter with a percutaneous needle or cannula placed in the subcutaneous tissue. For example, as of 1995, less than 5% of Type 1 diabetics in the United States were using pump therapy. There are now about 12% of the currently over 1,000,000 Type 1 diabetics in the U.S. using insulin pump therapy, and the percentage is now growing at an absolute rate of over 2% each year. Moreover, the number of Type 1 diabetics is growing at 3% or more per year. In addition, growing numbers of insulin using Type 2 diabetics are also using external insulin infusion pumps. Physicians have recognized that continuous infusion provides greater control of a diabetic&#39;s condition, and are also increasingly prescribing it for patients. In addition, medication pump therapy is becoming more important for the treatment and control of other medical conditions, such as pulmonary hypertension, HIV and cancer.  
         [0004]     Pump therapy systems have been developed that deliver medication by infusion into subcutaneous tissue using an infusion set with needles and/or a soft cannula. The soft cannula of the infusion set is normally inserted into the skin with a needle to prevent kinking of the soft cannula. Automatic insertion devices have been utilized to reduce the discomfort and pain involved with the insertion of infusion sets.  
         [0005]     In addition to delivering medication to a patient, other medical devices have been used to determine body characteristics by obtaining a sample of bodily fluid. A variety of implantable electrochemical sensors have been developed for detecting and/or quantifying specific agents or compositions in a patient&#39;s blood. For instance, glucose sensors have been developed for use in obtaining an indication of blood glucose levels in a diabetic patient. Such readings can be especially useful in monitoring and/or adjusting a treatment regimen that typically includes the regular administration of insulin to the patient. Thus, blood glucose readings are particularly useful in improving medical therapies with semi-automated medication infusion pumps of the external type, as generally described in U.S. Pat. Nos. 4,562,751; 4,678,408; and 4,685,903; or automated implantable medication infusion pumps, as generally described in U.S. Pat. No. 4,573,994, all of which are specifically incorporated by reference herein.  
       SUMMARY OF THE DISCLOSURE  
       [0006]     According to an embodiment of the invention, a dual insertion set is for supplying a fluid to the body of a patient and for monitoring a body characteristic of the patient. The dual insertion set includes a base, an infusion portion, and a sensor portion. The base may be used to secure the dual insertion set to the skin of a patient. The infusion portion has at least one cannula for supplying the fluid to an infusion placement site, which is coupled to and extends from the base. The at least one cannula has at least one lumen with a distal end for fluid communication with the placement site and at least one port structure formed near another end of the at least one lumen opposite the distal end. The sensor portion has at least one sensor coupled to and extending from the base having at least one sensor electrode formed on a substrate. The at least one sensor is for determining at least one body characteristic of the patient at a sensor placement site.  
         [0007]     Other embodiments include at least one piercing member. The at least one piercing member is coupled to and extends from the base to facilitate insertion of the at least one cannula and/or the at least one sensor.  
         [0008]     Alternative embodiments have the infusion portion and the sensor portion spaced a predetermined distance apart from one another. Additional embodiments include at least two separate piercing members to insert the at least one cannula and the at least one sensor into the body of the patient. Further embodiments have the infusion portion and the sensor portion equal in length. Other embodiments have the length of the sensor portion sized smaller relative to the length of the infusion portion. Still additional embodiments have the length of the infusion portion sized smaller relative to the length of the sensor portion. Particular embodiments provide metal needles as the piercing members.  
         [0009]     Further embodiments provide a cannula that includes an outer lumen to supply the fluid and an inner lumen to contain the sensor portion. The outer lumen may be sealed off at the distal end and the inner lumen may be open to allow the at least one sensor to protrude out of the inner lumen. In alternate embodiments, the outer lumen may contain the sensor portion and the inner lumen may supply the fluid. In still other embodiments, the cannula may include side-by-side lumens. The at least one cannula may also include at least one opening for infusing the fluid into the body of the patient. Additionally, one piercing member may be used to insert the dual insertion set into the body of the patient. Other embodiments may provide a sensor that includes at least one internal power supply. The internal power supply may further drive a leak detection system. Particular embodiments provide insulin as the infused fluid. In other embodiments, the monitored body characteristic may be blood glucose.  
         [0010]     According to another embodiment of the invention, a dual insertion set is for supplying a fluid to a body of a patient and for monitoring a body characteristic of the patient including a base, an infusion portion, a sensor portion and a piercing member. The base is used to secure the dual insertion set to the skin of a patient. The infusion portion includes at least one cannula for supplying a fluid to an infusion placement site, which is coupled to and extends from the base. The at least one cannula has at least one lumen with a distal end for fluid communication with the placement site and at least one port structure formed near another end of the at least one lumen opposite the distal end. The sensor portion includes at least one sensor having at least one sensor electrode formed on a substrate. The at least one sensor is for determining at least one body characteristic of the patient at a sensor placement site. The piercing member is coupled to and extends from the base to facilitate insertion of the at least one cannula and the at least one sensor. The at least one cannula of the illustrated embodiment may also include an outer lumen to supply the fluid and an inner lumen to contain the sensor portion. The outer lumen is sealed at the distal end and the inner lumen is open to allow the at least one sensor to protrude out of the inner lumen. The at least one cannula may also include at least one opening for infusing the fluid into the body of the patient. In some embodiments, the piercing member is a metal needle and the infused fluid is insulin. In other embodiments, the at least one monitored body characteristic is blood glucose. Additional embodiments may include an internal power supply for the at least one sensor. In further embodiments, the internal power supply may drive a leak detection system.  
         [0011]     According to yet another embodiment of the invention, a dual insertion set is for supplying a fluid to a body of a patient and for monitoring a body characteristic of the patient including a base, an infusion portion, a sensor portion and a piercing member. The base is used to secure the dual insertion set to the skin of a patient. The infusion portion includes at least one cannula for supplying a fluid to an infusion placement site, which is coupled to and extends from the base. The at least one cannula has at least one lumen with a distal end for fluid communication with the infusion placement site and at least one port structure formed near another end of the at least one lumen opposite the distal end. The sensor portion includes at least one sensor having at least one sensor electrode formed on a substrate. The at least one sensor is for determining at least one body characteristic of the patient at a sensor placement site. The piercing member is coupled to and extends from the base to facilitate insertion of the at least one cannula and the at least one sensor. The at least one sensor may be coupled to an outer wall of the at least one cannula.  
         [0012]     According to an alternative embodiment of the invention, a dual insertion set is for supplying a fluid to a body of a patient and for monitoring a body characteristic of the patient including a base, an infusion portion, a sensor portion and a piercing member. The base is used to secure the dual insertion set to the skin of a patient. The infusion portion includes a piercing member for penetrating the skin of the patient and for supplying a fluid to a placement site. The piercing member is coupled to and extends from the base. Additionally, the piercing member has at least one lumen with a distal end for fluid communication with an infusion placement site and at least one port structure formed near another end of the at least one lumen opposite the distal end. The sensor portion includes at least one sensor coupled to and extending from the base having at least one sensor electrode formed on a substrate. The at least one sensor is for determining at least one body characteristic of the patient at a sensor placement site. The at least one sensor is coupled to an outer wall of the piercing member.  
         [0013]     According to a further embodiment of the invention, a dual insertion set is for supplying a fluid to a body of a patient and for monitoring a body characteristic of the patient including a base, an infusion portion, a sensor portion and a piercing member. The base is used to secure the dual insertion set to the skin of a patient. The infusion portion includes a piercing member for penetrating the skin of the patient and for supplying a fluid to an infusion placement site. The piercing member is coupled to and extends from the base. Additionally, the piercing member has at least one lumen with a distal end for fluid communication with the infusion placement site and at least one port structure formed near another end of the at least one lumen opposite the distal end. The sensor portion includes at least one sensor having at least one sensor electrode formed on a substrate. The at least one sensor is placed on the skin of the patient and is for determining at least one body characteristic of the patient at a sensor placement site. In some embodiments, a piercing member may be used to withdraw fluid from the body of the patient to provide fluid contact with the at least one sensor electrode.  
         [0014]     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  
       [0015]     A detailed description of embodiments of the invention will be made with reference to the accompanying drawings, where like numerals designate corresponding parts or cross-sections in the several figures.  
         [0016]      FIG. 1  is a side view of a dual insertion set in accordance with an embodiment of the invention.  
         [0017]      FIG. 2  is a side view of a dual insertion set in accordance with another embodiment of the invention where a sensor and a cannula are placed at different depths in the body of a patient.  
         [0018]      FIG. 3  is a side view of a dual insertion set in accordance with a further embodiment of the invention where a sensor and a cannula are laterally spaced close to each other.  
         [0019]     FIGS.  4 ( a ) and  4 ( b ) are side and front views of a dual insertion set in accordance with an alternative embodiment of the invention where a cannula includes an outer lumen and an inner lumen, where a sensor is contained within the inner lumen of the cannula, which is sealed at its distal end.  
         [0020]     FIGS.  5 ( a ) and  5 ( b ) are side and front views of a dual insertion set in accordance with a further embodiment of the invention where a sensor portion is contained within an infusion portion, which is not sealed at its distal end.  
         [0021]      FIG. 6  is a side view of a dual insertion set in accordance with another embodiment of the invention where a sensor is coupled to the infusion portion.  
         [0022]      FIG. 7  is a side view of a dual insertion set in accordance with another embodiment of the invention where a piercing member replaces a cannula.  
         [0023]      FIG. 8  is a side view of a dual insertion set in accordance with another embodiment of the invention where a sensor is placed above the skin of a patient.  
         [0024]      FIG. 9  is a simplified block diagram of a dual insertion set coupled to an infusion pump in accordance with an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]     As shown in the drawings for purposes of illustration, the invention is embodied in a dual insertion set for supplying fluids to the body of patient in addition to monitoring body characteristics. In particular embodiments, the invention is embodied in a system for regulating the rate of insulin infusion into the body of a patient based on a glucose concentration measurement taken from the body. Embodiments of the invention may be employed in various infusion environments including, but not limited to a biological implant environment. Other environments include, but are not limited to external infusion devices, pumps, or the like.  
         [0026]     In some embodiments, the dual insertion set infuses a fluid, such as medication, chemicals, enzymes, antigens, hormones, vitamins or the like, into a body of a patient. In particular embodiments of the invention, the dual insertion set may be coupled to an external infusion device, which includes an RF programming capability, a carbohydrate (or bolus) estimation capability and/or vibration alarm capability, as described in U.S. Pat. No. 6,554,798 entitled “External Infusion Device with Remote Programming, Bolus Estimator and/or Vibration Alarm Capabilities,” which is specifically incorporated by reference herein. In other embodiments, the dual insertion set may be coupled to other infusion pumps such as the Animas IR-1250, the Deltec Cozmo®, the Disetronic D-Tron™plus, the MiniMed Paradigm® 515/715, and the Dana Diabecare® II. When coupled to an external infusion device, the dual insertion set may also include a disconnect cable, allowing the patient to easily disconnect the dual insertion set from the external infusion device to go swimming, take a shower or the like, without having to entirely remove the dual insertion set from the body of the patient. Particular embodiments are directed towards use in humans; however, in alternative embodiments, the dual insertion set may be used in animals.  
         [0027]     In further embodiments, the dual insertion set may be adapted to fit in an insertion tool, as described in U.S. Pat. No. 5,851,197 entitled “Injector For A Subcutaneous Infusion Set,” U.S. Pat. No. 6,093,172 entitled “Injector For A Subcutaneous Insertion Set,” and U.S. Pat. No. 6,607,509 entitled “Insertion Device For An Insertion Set And Method Of Using The Same,” all of which are specifically incorporated by reference herein. The dual insertion may be further adapted for low profile and unobtrusive placement on the patient. In other embodiments, the shape of the dual insertion set may be rectangular, circular, square or the like.  
         [0028]     A sensor included in the dual insertion set may be implanted in and/or through subcutaneous, dermal, sub-dermal, inter-peritoneal or peritoneal tissue. In other embodiments of the invention, the sensor may be coupled to a monitor for determining glucose levels in the blood and/or body fluids of the patient without the use of, or necessity of, a wire or cable connection between the transmitter and the monitor. In these embodiments, the sensor utilizes glucose oxidase to determine glucose levels. In still further embodiments, the sensor may use other materials such as optical, fluorescence or electrical materials to determine glucose levels. It will be recognized that further embodiments of the invention may be used to determine the levels of other agents, characteristics or compositions, such as hormones, cholesterol, medication concentrations, pH, oxygen saturation, viral loads (e.g., HIV), or the like. In other embodiments, the sensor may also include the capability to be programmed or calibrated using data received by a telemetered characteristic monitor transmitter device, or may be calibrated at the monitor device (or receiver), as described in U.S. Pat. No. 6,809,653 entitled “Telemetered Characteristic Monitor System And Method Of Using The Same,” which is specifically incorporated by reference herein. The telemetered characteristic monitor system may be primarily adapted for use in subcutaneous human tissue. However, still further embodiments may be placed in other types of tissue, such as muscle, lymph, organ tissue, veins, arteries or the like, and used in animal tissue. Embodiments may provide sensor readings on an intermittent, near-continuous and/or continuous basis.  
         [0029]     In some embodiments of the invention, the dual insertion set may be coated with medications or other agents that inhibit infection and/or promote healing of the insertion site, as described in U.S. Pat. No. 5,505,713 entitled “Indwelling Catheter With A Stable Enzyme Coating,” U.S. Pat. No. 6,475,196 entitled “Subcutaneous Infusion Cannula,” U.S. Pat. No. 6,770,729 entitled “Polymer Compositions containing Bioactive Agents and Methods for Their Use,” and U.S. Patent Application Publication No. 20030199837 entitled “Anti-Inflammatory Biosensor For Reduced Biofouling And Enhanced Sensor Performance,” all of which are specifically incorporated by reference herein. Particular embodiments of the dual insertion set are for transcutaneous placement of the dual insertion set in subcutaneous tissue. In still further embodiments, the sensor portion and infusion portion of the dual insertion may be placed at different depths within the body of the patient.  
         [0030]     The dual insertion set may be used to monitor body characteristics of the patient. In one embodiment, the sensor portion of the dual insertion set monitors blood glucose levels and can be used in conjunction with automated and/or semi-automated medication infusion pumps. In additional embodiments, the sensor portion may be used to determine the levels of other agents, characteristics or compositions, such as hormones, cholesterol, medication concentrations, pH, oxygen saturation, viral loads (e.g., HIV), or the like.  
         [0031]     The infusion portion of the dual insertion set may be used to provide fluids to the body of a patient. In one embodiment, the infusion portion provides insulin to a diabetic patient. In other embodiments, the infusion portion provides medication, chemicals, enzymes, antigens, hormones, vitamins or the like, to the body of the patient.  
         [0032]     In particular embodiments, the dual insertion set includes at least one piercing member to pierce the skin during insertion. The piercing member may be a metal needle, hollow, solid, half needle (or other fraction) or the like having a diameter in the range of 18 gauge—29 gauge, or the like, or any range there between. In other embodiments, the piercing member may be made out of other materials, such as ceramic, plastic, composites, silicon micro-needles, biodegradable, hydrophilic substances, substances that soften and/or change once in contact with the body and/or bodily fluids, or the like. In other embodiments, the dual insertion set may include multiple piercing members, only one piercing member, and/or no piercing members. In still further embodiments, the piercing member can replace the cannula and remain in the body to deliver fluids.  
         [0033]     As illustrated in  FIG. 1 , a dual insertion set  10  in accordance with an embodiment of the present invention includes a sensor portion  20 , an infusion portion  30 , a base  40 , a sensor  22 , a cannula  33 , and piercing members  24  and  34 . Both portions  20  and  30  of the dual insertion set  10  are secured to base  40 . Infusion portion  30  is connected at one end to tubing  50  that is connected to an external infusion device, pump or the like ( FIG. 9 ). The sensor portion  20  is particularly designed for facilitating accurate placement of a sensor, i.e., a flexible thin film electrochemical sensor of the type used for monitoring specific blood parameters representative of a patient condition, as described in U.S. Pat. No. 5,391,250 entitled “Method of Fabricating Thin Film Sensors” and U.S. Pat. No. 6,484,046 entitled “Electrochemical Analyte Sensor,” both of which are specifically incorporated by reference herein. In some embodiments, the sensor portion  20  is used to monitor blood glucose levels in diabetic patients as described in U.S. Pat. Nos. 5,390,671, 5,568,806 and 5,586,553, entitled “Transcutaneous Sensor Insertion Set,” all of which are specifically incorporated by reference herein.  
         [0034]     In the illustrated embodiment, sensor portion  20  of the dual insertion set  10  is provided for placement of a sensor  22  at a selected sensor placement site within the body of a patient. Sensor portion  20  includes a rigid hollow sensor insertion needle  24  for placement of the sensor distal segment having one or more exposed sensor electrodes. Insertion needle  24  is withdrawable to leave the sensor  22  electrodes in place at the selected site. In some embodiments, the sensor may be made from a substrate with notches cut in the substrate to from a necked down region in the substrate, as described in U.S. Pat. No. 6,484,045 entitled “Analyte Sensor and Method of Making the Same” and U.S. Patent Application Publication No. 20020032374 entitled “Improved Analyte Sensor and Method of Making the Same,” both of which are specifically incorporated by reference herein.  
         [0035]     The sensor  22  is carried by base  40  adapted for placement on the patient&#39;s skin. Base  40  includes an enlarged and generally rectangular pad having an underside surface coated with a suitable pressure sensitive adhesive. The base may come in other shapes including, but not limited to, circular, square, triangular, trapezoidal, octagonal, or the like. The base may also come in various sizes. A peel off paper may be provided to cover and protect the adhesive layer until the dual insertion set  10  is ready for use. In alternative embodiments, the base  40  may be affixed to a suitable adhesive material that can hold the dual insertion set to the body.  
         [0036]     The dual insertion set  10  may be designed to place the sensor  22  and cannula  33  subcutaneously or at another selected site within the body of a patient, in a manner minimizing patient discomfort and trauma. In the illustrated embodiment, the sensor  22  and cannula  33  are inserted into the body of the patient using piercing members  24  and  34 . However, additional embodiments may include only one piercing member used to insert sensor  22  and cannula  33  into the body of the patient. In still further embodiments multiple needles, micro-needles or the like may be used to insert sensor  22  and cannula  33 .  
         [0037]     The infusion portion  30  of the illustrated embodiment may be used for delivering fluid, liquid, medication or the like to a patient on a continuous and/or programmable basis over an extended period of time, such as, for example, the administration of insulin to a diabetic patient by means of programmable external infusion device ( FIG. 9 ). In some embodiments, the infusion portion  30  of the dual insertion  10  is of the type described in U.S. Pat. No. 4,755,173 entitled “Soft Cannula Subcutaneous Injection Set,” which is specifically incorporated by reference herein. Other embodiments may be formed similar to those described in U.S. Pat. No. 6,017,328 entitled “Device For Subcutaneous Medication Delivery,” U.S. Pat. No. 5,968,011 entitled “Subcutaneous Injection Set,” U.S. Pat. No. 6,086,575 entitled “Subcutaneous Infusion Device,” and U.S. Pat. No. 6,736,797 entitled “Subcutaneous Infusion Set,” all of which are specifically incorporated by reference herein. Alternative embodiments may include a cannula with the added capability to withdraw fluids from the body of the patient.  
         [0038]     In use, the dual insertion set  10  of the illustrated embodiment permits accurate placement of the sensor  22  and cannula  33  at selected sensor and infusion placement sites within the body of the patient in a manner minimizing patient discomfort and trauma. More specifically, a peel-off paper may be removed from the pad at which time the base  40  can be pressed onto and seated upon the patient skin. During this step, insertion needles  24  and  34  pierce the patient&#39;s skin and carry the sensor  22  along with the cannula  33  to the appropriate sensor and infusion placement sites in the body of the patient. After the dual insertion set  10  is placed onto the skin of the patient, needles  24  and  34  can be withdrawn from the patient. During this withdrawal step, sensor insertion needle  24  slides over sensor  22  leaving the sensor  22  in direct contact with the patient&#39;s bodily fluid. The infusion needle  34  may be withdrawn from within the cannula  33 , leaving the cannula  33  in a sub-dermal location within the body of the patient. Alternative embodiments place the sensor and/or cannula in the transcutaneous, subcutaneous, dermal, inter-peritoneal or peritoneal tissue of the patient. In still further embodiments, the sensor and/or cannula may be placed in the body of the patient using insertion tools of the type described in U.S. Pat. No. 6,093,172 entitled “Injector For A Subcutaneous Insertion Set,” U.S. Pat. No. 6,293,925 entitled “Insertion Device for an Insertion Set and Method of Using the Same,” and U.S. Pat. No. 6,607,509 entitled “Insertion Device for an Insertion Set and Method of Using the Same,” all of which are specifically incorporated by reference herein.  
         [0039]     The sensor  22  and cannula  33  of the illustrated embodiment may be laterally spaced apart from each another. In some embodiments, the lateral distance between the sensor  22  and cannula  33  may be in the range of 10 mm-40 mm, or the like, or other ranges there between. Alternative embodiments may use smaller displacements from 0-10 mm. In still other embodiments, the sensor  22  and cannula  33  may be laterally spaced side-by-side ( FIG. 4 ,  FIG. 6 ). Alternate embodiments may space the sensor  22  and cannula  33  axially, diagonally, or the like. In still other embodiments, the length of cannula  33  may be in the range of 3 mm-12 mm, or the like, or other ranges there between. In further embodiments, the length of cannula  33  may be less than 3 mm and/or greater than 12 mm. In other embodiments, the insertion angle of cannula  33  may vary depending on certain factors including but not limited to body type, body weight, placement site location and the like. These angles range from 0 degrees to 90 degrees relative to the base. In still further embodiments, the length and position of sensor  22  may vary in a similar fashion to the variations of cannula  33  in previous embodiments.  
         [0040]     As shown in  FIG. 2 , a dual insertion set  110  in accordance with an embodiment of the present invention includes a sensor portion  120 , an infusion portion  130 , a base  140 , a sensor  122 , a cannula  133 , and piercing members  124  and  134 . Both portions  120  and  130  of the dual insertion set  110  are secured to base  140 , similar to the previous embodiments. However, in the illustrated embodiment, the length of sensor portion  120  is smaller, compared to the length of the infusion portion  130 . In this embodiment, the sensor  122  may be placed at a different depth in the body of the patient, due its shorter size. In other embodiments, the cannula  133  maybe sized shorter in length relative to the sensor  122 . The variations in length of the sensor  122  and the cannula  133  are determined by many factors including, but not limited to, the sensor and infusion placement site location on the body of the patient, the patient&#39;s relative sensitivity in the sensor and infusion placement site location, and the like. Additionally, in the illustrated embodiment, sensor piercing member  124  and infusion piercing member  134  may be sized according to the length of sensor  122  and cannula  133 . In some embodiments, the piercing members  124  and  134  are sized slightly longer than the sensor  122  and cannula  133 .  
         [0041]     As shown in  FIG. 3 , a dual insertion set  210  in accordance with an embodiment of the present invention includes a sensor portion  220 , an infusion portion  230 , a base  240 , a sensor  222 , a cannula  233 , and piercing members  224  and  234 . The sensor portion  220  may also include a power supply  260 , positioned on the base  240  above the sensor  222 . The inclusion of a power supply may allow the sensor to transmit readings to an external infusion device (see  FIG. 9 ). In alternative embodiments, the power supply may allow the sensor to transmit readings to a glucose monitor, a medication device, a PDA, a PC, a laptop, the internet, or the like. In additional embodiments, the power supply  260  may provide the capability to use the power for a leak detection system at the placement site as described in U.S. Pat. No. 6,461,329 entitled “Infusion Site Leak Detection System and Method of Using the Same,” which is specifically incorporated by reference herein. In other embodiments of the invention, the power supply  260  may be used to power an alarm or similar feature added to the dual insertion set. In additional embodiments, the power supply may be removable to allow use of the power supply on different insertion sets. In these embodiments, the power supply may attach or clip onto the dual insertion using various methods known in the art.  
         [0042]     As shown in FIGS.  4 ( a ) and  4 ( b ), a dual insertion set  310  in accordance with another embodiment of the present invention includes a base  340 , a sensor  322 , a cannula  333  with openings  332 . The cannula  333  further includes an outer lumen  350  and an inner lumen  360 . The outer lumen of cannula  333  may be sealed at its distal end  331 . In the illustrated embodiment, the dual insertion set  310  may use a single piercing member (not shown) to place the cannula  333  and the sensor  322  at a single placement site in the body of the patient. The outer lumen  350  is for infusing the fluid into the body of the patient through the openings  332 . The inner lumen  360  may contain the sensor  322 . Since the outer lumen  350  is sealed at its distal end  331  infused fluid avoids contact with the sensor  322 . The sensor  322  protrudes out of the inner lumen  350  to monitor a body characteristic. In use, fluid enters the outer lumen  350  of cannula  333  and is dispensed into the body of the patient through openings  332  located around cannula  333 . In this configuration, sensor  322  is not affected by infused insulin because the outer lumen  350  is sealed off at the distal tip  331  and the fluid is dispersed into the body of the patient via openings  332  away from the sensor  322 . In alternative embodiments, the openings  332  may be replaced and/or used in combination with more or less openings, windows, porous membranes or the like.  
         [0043]     As shown in FIGS.  5 ( a ) and  5 ( b ), a dual insertion  410  in accordance with yet another embodiment of the present invention includes a base  440 , a sensor  422  and a cannula  433 . The cannula  433  further includes an outer lumen  450  and an inner lumen  460 . The outer lumen of cannula  433  may be open at its distal end  431 . In the illustrated embodiment, the dual insertion set  410  uses a single piercing member (not shown) to place the cannula  433  and the sensor  422  at a single placement site in the body of the patient. The outer lumen  450  is for infusing fluid into the body of the patient through its distal end opening  431 . The inner lumen  460  contains the sensor  422 . The sensor  422  protrudes out of the inner lumen  450  to monitor a body characteristic. The sensor  422  is positioned a predetermined distance L 2  into the body of the patient. In the illustrated embodiment, the cannula  433  is much shorter in length, having a length L 1 . In use, the sensor  422  is placed deep within the sub-dermal portion of the body to achieve accurate body characteristic readings, while insuring no interference from the infused fluid from cannula  433 . Having distal end  431  open allows the infused fluid to enter the body of the patient directly through the outer lumen of the cannula  433 . This embodiment may be easier to manufacture than the previously described embodiment in FIGS.  4 ( a ) and  4 ( b ). The placement depth characteristics L 1  and L 2  range from 3 mm to 12 mm in size, depending on the type of fluid/sensor combination being used. In other embodiments, shorter and/or longer dimensions may be utilized including less than 3 mm and/or greater than 12 mm.  
         [0044]     As shown in  FIG. 6 , a dual insertion set  510  in accordance with another embodiment of the present invention includes a sensor portion  520 , an infusion portion  530 , a base  540 , a sensor  522 , a cannula  533 , and single piercing member  534 . In the illustrated embodiment, the sensor  522  directly attaches to the cannula  533 . In some embodiments, the sensor  522  may lay along side an outer wall of the cannula  533 , while other embodiments may have a flexible sensor concentrically surrounding the diameter of the cannula  533 . The single piercing member  534  inserts the sensor  522  and the cannula  533  into the body of the patient, eliminating the need for multiple piercing members, thus minimizing patient discomfort and trauma. In alternative embodiments, the sensor may be made from a substrate with notches cut in the substrate to from a necked down region in the substrate, as described in U.S. Pat. No. 6,484,045 entitled “Analyte Sensor and Method of Making the Same” and U.S. Patent Application Publication No. 20020032374 entitled “Improved Analyte Sensor and Method of Making the Same,” both of which are specifically incorporated by reference herein.  
         [0045]     As shown in  FIG. 7 , a dual insertion set  610  in accordance with yet another embodiment of the present invention includes a sensor portion  620 , an infusion portion  630 , a base  640 , a sensor  622  and a piercing member  633 . The cannula  133  ( FIG. 1 ) may be removed entirely from the dual insertion set  610 , being replaced by a piercing member  633 . The piercing member  633  may serve the dual function of inserting the sensor into the body of the patient along with delivering fluid into the body of the patient. In the illustrated embodiment, the piercing member  633  may be a hollow, thin needle having a diameter in the range of 18 gauge to 33 gauge. The needle  633  may be a metal needle, hollow, solid, half needle (or other fraction) or the like. In use, the piercing member  633  can puncture the skin of the patient and deliver fluids to the patient, similar to the cannula of the previous embodiments. Furthermore, piercing member  633  may be capable of remaining in the body of the patient for an extended period of time, without causing noticeable discomfort. In alternative embodiments, the sensor may be applied and/or formed directly onto the piercing member as described in previous embodiments.  
         [0046]     As shown in  FIG. 8 , a dual insertion set  710  in accordance with another embodiment of the present invention includes a sensor portion  720 , an infusion portion  730 , a base  740 , a sensor  722  and a piercing member  733 . The sensor  722  is placed underneath the base  740 . The cannula  133  ( FIG. 1 ) may be removed entirely from the dual insertion set  710 , being replaced by a piercing member  733 . In the illustrated embodiment, the piercing member  733  can deliver fluids as well as withdraw fluids from the body of the patient. Fluid is withdrawn from the patient via piercing member  733  and passes through sensor  733  where it is analyzed to determine a body characteristic level, i.e., blood glucose levels in a diabetic patient. In the illustrated embodiment, the piercing member may be replaced and/or used in conjunction with a cannula as described in previous embodiments.  
         [0047]     In still a further embodiment shown in  FIG. 9 , a dual insertion set  810  is shown in a block diagram configuration connected to a system that includes a power supply  860 , a sensor processing module  870 , an external infusion device  840  and infusion tubing  850 . The dual insertion set  810  includes a sensor portion  820  and an infusion portion  830 . The infusion portion  830  is coupled to infusion tubing  850  that receives fluid from the external infusion device  840 . The sensor portion  820  is coupled to the power supply  860  and the sensor processing module  870 , which are both coupled to the external infusion device  840 .  
         [0048]     While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.  
         [0049]     The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.