US20060041229A1 - Flow restriction system and method for patient infusion device - Google Patents

Abstract

A device for delivering fluid, such as insulin for example, to a patient. The device includes a flow path having an exit port assembly adapted to connect to a transcutaneous patient access tool, and a reservoir connected to the exit port assembly. The device also includes a flow restriction system having an air removal filter communicating with the flow path and allowing air to exit the flow path and preventing fluid from exiting the flow path, and a flow restrictor positioned within the flow path between the air removal filter and the exit port assembly. Among other features and advantages, the flow restriction system of the present invention allows the flow path of the fluid delivery device to be purged of air, or “primed” prior to operation, such that desired volumes of fluid can be accurately delivered by the device.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• The present application is a divisonal of co-pending U.S. patent application Ser. No. 10/198,690, filed on Jul. 16, 2002, which is assigned to the assignee of the present application and incorporated herein by reference.
FIELD OF THE INVENTION
• The present invention relates generally to medical devices, systems and methods, and more particularly to small, low cost, portable infusion devices and methods that are useable to achieve precise, sophisticated, and programmable flow patterns for the delivery of therapeutic liquids such as insulin to a mammalian patient. Even more particularly, the present invention is directed to fluid flow restriction systems and methods for an infusion device. Among other benefits and features, the fluid flow restriction systems and methods of the present invention ensure adequate priming of infusion devices prior to use, and the delivery of accurate volumes of fluid from the infusion devices during their use.
BACKGROUND OF THE INVENTION
• Today, there are numerous diseases and other physical ailments that are treated by various medicines including pharmaceuticals, nutritional formulas, biologically derived or active agents, hormonal and gene based material and other substances in both solid or liquid form. In the delivery of these medicines, it is often desirable to bypass the digestive system of a mammalian patient to avoid degradation of the active ingredients caused by the catalytic enzymes in the digestive tract and liver. Delivery of a medicine other than by way of the intestines is known as parenteral delivery. Parenteral delivery of various drugs in liquid form is often desired to enhance the effect of the substance being delivered, insuring that the unaltered medicine reaches its intended site at a significant concentration. Also, undesired side effects associated with other routes of delivery, such as systemic toxicity, can potentially be avoided.
• Often, a medicine may only be available in a liquid form, or the liquid version may have desirable characteristics that cannot be achieved with solid or pill form. Delivery of liquid medicines may best be accomplished by infusing directly into the cardiovascular system via veins or arteries, into the subcutaneous tissue or directly into organs, tumors, cavities, bones or other site specific locations within the body. Parenteral delivery of liquid medicines into the body is often accomplished by administering bolus injections using a needle and reservoir, or continuously by gravity driven dispensers or transdermal patch technologies. Bolus injections often imperfectly match the clinical needs of the patient, and usually require larger individual doses than are desired at the specific time they are given. Continuous delivery of medicine through gravity feed systems compromise the patient's mobility and lifestyle, and limit the therapy to simplistic flow rates and profiles. Transdermal patches have special requirements of the medicine being delivered, particularly as it relates to the molecular structure, and similar to gravity feed systems, the control of the drug administration is severely limited.
• Ambulatory infusion pumps have been developed for delivering liquid medicaments to a patient. These infusion devices have the ability to offer sophisticated fluid delivery profiles accomplishing bolus requirements, continuous infusion and variable flow rate delivery. These infusion capabilities usually result in better efficacy of the drug and therapy and less toxicity to the patient's system. An example of a use of an ambulatory infusion pump is for the delivery of insulin for the treatment of diabetes mellitus. These pumps can deliver insulin on a continuous basal basis as well as a bolus basis as is disclosed in U.S. Pat. No. 4,498,843 to Schneider et al.
• The ambulatory pumps often work with a reservoir to contain the liquid medicine, such as a cartridge, a syringe or an IV bag, and use electro-mechanical pumping or metering technology to deliver the medication to the patient via tubing from the infusion device to a needle that is inserted transcutaneously, or through the skin of the patient. The devices allow control and programming via electromechanical buttons or switches located on the housing of the device, and accessed by the patient or clinician. The devices include visual feedback via text or graphic screens, such as liquid crystal displays known as LCD's, and may include alert or warning lights and audio or vibration signals and alarms. The device can be worn in a harness or pocket or strapped to the body of the patient. Currently available ambulatory infusion devices are expensive, difficult to program and prepare for infusion, and tend to be bulky, heavy and very fragile. Filling these devices can be difficult and require the patient to carry both the intended medication as well as filling accessories. The devices require specialized care, maintenance, and cleaning to assure proper functionality and safety for their intended long term use. Due to the high cost of existing devices, healthcare providers limit the patient populations approved to use the devices and therapies for which the devices can be used.
• Clearly, therefore, there was a need for a programmable and adjustable infusion system that is precise and reliable and can offer clinicians and patients a small, low cost, light-weight, easy-to-use alternative for parenteral delivery of liquid medicines. In response, the applicant of the present application provided a small, low cost, light-weight, easy-to-use device for delivering liquid medicines to a patient. The device, which is described in detail in co-pending U.S. application Ser. No. 09/943,992, filed on Aug. 31, 2001, includes an exit port, a dispenser for causing fluid from a reservoir to flow to the exit port, a local processor programmed to cause a flow of fluid to the exit port based on flow instructions from a separate, remote control device, and a wireless receiver connected to the local processor for receiving the flow instructions. To reduce the size, complexity and costs of the device, the device is provided with a housing that is free of user input components, such as a keypad, for providing flow instructions to the local processor. Such devices for delivering liquid medicines to a patient are preferably purged of air, or “primed” prior to operation such that desired volumes of fluid are accurately delivered by the devices. What is still desired, therefore, are new and improved devices for delivering fluid to a patient. Preferably, the fluid delivery devices will be simple in design, and inexpensive and easy to manufacture, in order to further reduce the size, complexity and costs of the devices, such that the devices lend themselves to being small and disposable in nature. In addition, the fluid delivery device will preferably include a flow restriction system and method that primes the devices prior to operation.
SUMMARY OF THE INVENTION
• The present invention provides a device for delivering fluid, such as insulin for example, to a patient. The device includes a flow path having an exit port assembly adapted to connect to a transcutaneous patient access tool (e.g., needle), and a reservoir connected to the exit port assembly. The device also includes a flow restriction system having an air removal filter communicating with the flow path and allowing air to exit the flow path and preventing fluid from exiting the flow path, and a flow restrictor positioned within the flow path between the air removal filter and the exit port assembly. Among other features and advantages, the flow restriction system of the present invention allows the flow path of the fluid delivery device to be purged of air, or “primed” prior to operation, such that desired volumes of fluid can be accurately delivered by the device. According to one aspect of the present invention, the flow restrictor of the flow restriction system comprises an outlet plug removably connected to the exit port assembly to prevent fluid from exiting the flow path through the exit port assembly. According to another aspect, the exit port assembly of the fluid delivery device includes a transcutaneous patient access tool and the outlet plug is removably connected to the access tool. According to a further aspect, the transcutaneous patient access tool comprises a needle having a distal end for insertion into a patient and the outlet plug is removably connected to the distal end of the needle.
• According to another aspect of the present invention, the air removal filter of the flow restriction system comprises at least a portion of the outlet plug allowing air to exit the flow path through the exit port assembly. According to an additional aspect, the air removal filter of the outlet plug comprises one of PTFE and polyethylene. According to a further aspect, the air removal filter of the outlet plug is provided with predetermined physical properties (e.g., pore size and/or thickness) such that the filter expands upon the flow path being substantially primed. According to yet another aspect, the air bubble removal filter of the outlet plug comprises needle septum material. According to an additional aspect of the present invention, the flow restriction system further comprises a second air removal filter positioned between the fill port and the reservoir. According to another aspect, the flow restriction system further comprises a second flow restrictor positioned between the second air removal filter and the reservoir. According to a further aspect of the present invention, the flow restriction system also includes a sensor assembly monitoring fluid flow conditions within the flow path.
• According to one aspect, the sensor assembly includes a resilient diaphragm having opposing first and second surfaces, with the first surface of the diaphragm positioned against the flow path, a chamber wall positioned adjacent the second surface of the diaphragm and defining a sensor chamber adjacent the second surface of the diaphragm, and at least one sensor arranged to provide a signal when the second surface of the diaphragm expands into the chamber. According to an additional aspect, the sensor assembly is adapted to provide a signal to the processor when the flow path is primed. The present invention also provides a method for restricting fluid flow in a flow path of a fluid delivery device having an exit port assembly adapted to connect to a transcutaneous patient access tool. The method includes preventing fluid from exiting the flow path, allowing air to exit the flow path at an air removal point within the flow path, and restricting fluid flow through the flow path between the air removal point and the exit port assembly. These aspects of the invention together with additional features and advantages thereof may best be understood by reference to the following detailed descriptions and examples taken in connection with the accompanying illustrated drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of a first exemplary embodiment of a fluid delivery device constructed in accordance with the present invention shown secured on a patient, and a remote control device for use with the fluid delivery device (the remote control device being enlarged with respect to the patient and the fluid delivery device for purposes of illustration);
• FIG. 2 is an enlarged top sectional view of the fluid delivery device ofFIG. 1;
• FIG. 3 is an enlarged side elevation view, partially cut-away, of the fluid delivery device ofFIG. 1;
• FIG. 4 is an enlarged bottom plan view of the fluid delivery device ofFIG. 1;
• FIG. 5 is an enlarged top sectional view of another exemplary embodiment of a fluid delivery device constructed in accordance with the present invention;
• FIG. 5ais a further enlarged sectional view of an exemplary embodiment of a flow sensor assembly of the fluid delivery device ofFIG. 5;
• FIG. 6 is a graph illustrating an exemplary embodiment of a method of restricting flow according to the present invention as carried out by the flow sensor assembly of the fluid delivery device ofFIGS. 5 and 5a;
• FIG. 7 is a sectional view of another exemplary embodiment of a flow restriction system constructed in accordance with the present invention;
• FIG. 8 is an enlarged sectional view of a portion of the exemplary embodiment of a flow restriction system contained incircle8 ofFIG. 7;
• FIG. 9 is an enlarged sectional view of an exemplary embodiment of an outlet plug constructed in accordance with the present invention for use as part of the flow restriction system ofFIG. 4a;
• FIG. 10ais a further enlarged sectional view of the outlet plug ofFIG. 9;
• FIG. 10bis an enlarged sectional view of the outlet plug ofFIG. 9 shown received on an exit port cannula of the fluid delivery device, after the device has been filled with fluid and purged of air;
• FIG. 11 is a sectional view of an additional exemplary embodiment of a flow restriction system constructed in accordance with the present invention;
• FIG. 12 is a side elevation view, partially cut-away, showing another exemplary embodiment of outlet plug constructed in accordance with the present invention, received on an exit port cannula of a fluid delivery device with a needle of a syringe inserted into the outlet plug for injecting fluid into the exit port cannula and the fluid delivery device;
• FIG. 13 is a side elevation view, partially cut-away, showing an additional exemplary embodiment of outlet plug constructed in accordance with the present invention, received on an exit port cannula;
• FIG. 14 is a side elevation view, partially cut-away, showing a further exemplary embodiment of outlet plug constructed in accordance with the present invention, received on an exit port cannula;
• FIGS. 15aand15bare top plan views of another exemplary embodiment of an outlet plug constructed in accordance with the present invention, respectively showing an air bubble filter of the outlet plug before and after expansion;
• FIGS. 16aand16bare side sectional views of another exemplary embodiment of an outlet plug constructed in accordance with the present invention, respectively showing an air bubble filter of the outlet plug before and after expansion;
• FIG. 17 is a side elevation view showing another exemplary embodiment of outlet plug constructed in accordance with the present invention, received on an exit port cannula of a fluid delivery device;
• FIG. 18 is a side elevation view showing an additional exemplary embodiment of outlet plug constructed in accordance with the present invention, received on an exit port cannula of a fluid delivery device;
• FIG. 19 is a side elevation view, partially cut-away, showing an exemplary embodiment of a package constructed in accordance with the present invention, and containing a fluid delivery device;
• FIG. 20ais a side elevation view, partially cut-away, showing an exemplary embodiment of a fluid delivery device and an outlet plug constructed in accordance with the present invention;
• FIG. 20bis a side elevation view, partially cut-away, showing the outlet plug removed from the fluid delivery device ofFIG. 20a;
• FIG. 21 is a representation of an exemplary embodiment of a flow path constructed in accordance with the present invention for use in a fluid delivery device;
• FIG. 22 is a side elevation view, partially cut-away, showing an exemplary embodiment of an exit port assembly and an outlet plug constructed in accordance with the present invention for use in a fluid delivery device;
• FIG. 23 is a sectional view showing an exemplary embodiment of a fluid delivery device and an outlet plug constructed in accordance with the present invention;
• FIG. 24 is an enlarged sectional view of a pressure sensor of the fluid delivery device ofFIG. 23;
• FIG. 25 is an enlarged sectional view of the outlet plug ofFIG. 23;
• FIG. 26 is a sectional view showing the outlet plug ofFIG. 23 attached to an exit port assembly of the fluid delivery device ofFIG. 23; and
• FIG. 27 is an enlarged sectional view of the outlet plug attached to the exit port assembly contained incircle27 ofFIG. 26.
• Like reference characters designate identical or corresponding components and units throughout the several views.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• Referring first toFIG. 2, there is illustrated afluid delivery device10 including aflow restriction system200 constructed in accordance with the present invention. Theflow restriction system200 operates to substantially prime (i.e., purge of air) aflow path12 of thefluid delivery device10 prior to operation of thedevice10, to ensure that a desired volume of fluid is accurately delivered by thedevice10 during operation.
• Thefluid delivery device10 ofFIG. 2, and which is also shown inFIGS. 3 and 4, can be used for the delivery of fluids to a person or animal. The types of liquids that can be delivered by thefluid delivery device10 include, but are not limited to, insulin, antibiotics, nutritional fluids, total parenteral nutrition or TPN, analgesics, morphine, hormones or hormonal drugs, gene therapy drugs, anticoagulants, analgesics, cardiovascular medications, AZT or chemotherapeutics. The types of medical conditions that thefluid delivery device10 might be used to treat include, but are not limited to, diabetes, cardiovascular disease, pain, chronic pain, cancer, AIDS, neurological diseases, Alzheimer's Disease, ALS, Hepatitis, Parkinson's Disease or spasticity. In addition, it should be understood that theflow restriction assembly200 according to the present invention can be used with fluid delivery devices other than those used for the delivery of fluids to persons or animals.
• Theflow path12 of thefluid delivery device10, as shown inFIG. 2, generally includes areservoir30 for receiving and holding the fluid to be delivered by thedevice10, anexit port assembly70 connected to the reservoir, and a fill port connected to the reservoir. Thefluid delivery device10 also includes adispenser40 for causing fluid from thereservoir30 to flow to theexit port assembly70.
• The volume of thereservoir30 is chosen to best suit the therapeutic application of thefluid delivery device10 impacted by such factors as available concentrations of medicinal fluids to be delivered, acceptable times between refills or disposal of thefluid delivery device10, size constraints and other factors. Thereservoir30 may be prefilled by the device manufacturer or a cooperating drug manufacturer, or may include external filling means, such as afill port90 having needle insertion septum or a Luer connector, for example. In addition, thedevice10 can be provided with a removable reservoir.
• Theexit port assembly70 can include elements to penetrate the skin of the patient, such that the entire volume of theflow path12 of thefluid delivery device10 is predetermined. For example, in the exemplary embodiment shown inFIG. 3, a needle-connection tubing terminating in askin penetrating cannula72 is provided as an integral part of theexit port assembly70. Theexit port assembly70 can further be provided with injection means, such as a spring-biased mechanism driven by a shaped memory element, to inject theskin penetrating cannula72 into a patient when thefluid delivery device10 is correctly positioned on the patient. For example, if the cannula is a flexible tube, a rigid penetrator within the lumen of the tube can be driven through the skin by the injection means and then withdrawn, leaving the soft cannula in place in the subcutaneous tissue of the patient or other internal site.
• Examples of injection means for the exit port assembly are shown in co-pending U.S. patent application Ser. No. 10/037,902, filed on Nov. 9, 2001 (Atty. Docket No. INSL-114), and entitled TRANSCUTANEOUS DELIVERY MEANS, and U.S. patent application Ser. No. 10/128,206, filed on Apr. 23, 2002 (Atty. Docket No. INSL-121), and entitled TRANSCUTANEOUS FLUID DELIVERY SYSTEM, both of which are assigned to the assignee of the present application and incorporated herein by reference.
• Alternatively, the injection means may be removable soon after transcutaneous penetration. In addition, theexit port assembly70 can simply be adapted to connect with a Luer connector for example, to a separate, standard infusion device that includes a skin penetrating cannula. Theexit port assembly70 can alternatively be adapted to connect through tubing to another medical device.
• It should be understood that, as used herein, the term “flow path”12 is meant to include all portions of thefluid delivery device10 that contain therapeutic fluid for delivery to a patient, e.g., all portions between thefill port90 of thereservoir30 to the tip of theneedle72 of theexit port assembly72.
• Thefluid delivery device10 also includes a processor or electronic microcontroller (hereinafter referred to as the “local” processor)50 connected to thedispenser40. Thelocal processor50 is programmed to cause a flow of fluid to theexit port assembly70 based on flow instructions from a separate,remote control device100, an example of which is shown inFIG. 1.
• Referring also toFIG. 1, thefluid delivery device10 further includes awireless receiver60 connected to thelocal processor50 for receiving flow instructions from a separate,remote control device100 and delivering the flow instructions to thelocal processor50. Thedevice10 also includes ahousing20 containing theexit port assembly70, thereservoir30, thedispenser40, thelocal processor50, and thewireless receiver60.
• As shown best inFIGS. 3 and 4, thehousing20 of thefluid delivery device10 is free of user input components for providing flow instructions to thelocal processor50, such as electromechanical switches or buttons on an outer surface of thehousing20, or interfaces otherwise accessible to a user to adjust the programmed flow rate through thelocal processor50. The lack of user input components allows the size, complexity and costs of thedevice10 to be substantially reduced so that thedevice10 lends itself to being small and disposable in nature. Examples of such devices are disclosed in co-pending U.S. patent application Ser. No. 09/943,992, filed on Aug. 31, 2001 (Atty. Docket No. INSL-110), and entitled DEVICES, SYSTEMS AND METHODS FOR PATIENT INFUSION, which is assigned to the assignee of the present application and has previously been incorporated herein by reference.
• In order to program, adjust the programming of, or otherwise communicate user inputs to thelocal processor50, thefluid delivery device10 includes the wireless communication element, orreceiver60 for receiving the user inputs from the separate,remote control device100 ofFIG. 1. Signals can be sent via a communication element (not shown) of theremote control device100, which can include or be connected to anantenna130, shown inFIG. 1 as being external to thedevice100.
• Theremote control device100 has user input components, including an array of electromechanical switches, such as themembrane keypad120 shown. Thecontrol device100 also includes user output components, including a visual display, such as a liquid crystal display (LCD)110. Alternatively, the control device can be provided with a touch screen for both user input and output. Although not shown inFIG. 1, theremote control device100 has its own processor (hereinafter referred to as the “remote” processor) connected to themembrane keypad120 and theLCD110. The remote processor receives the user inputs from themembrane keypad120 and provides “flow” instructions for transmission to thefluid delivery device10, and provides information to theLCD110. Since theremote control device100 also includes avisual display110, thefluid delivery device10 can be void of an information screen, further reducing the size, complexity and costs of thedevice10.
• Thecommunication element60 of thedevice10 preferably receives electronic communication from theremote control device100 using radio frequency or other wireless communication standards and protocols. In a preferred embodiment, thecommunication element60 is a two-way communication element, including a receiver and a transmitter, for allowing thefluid delivery device10 to send information back to theremote control device100. In such an embodiment, theremote control device100 also includes an integral communication element comprising a receiver and a transmitter, for allowing theremote control device100 to receive the information sent by thefluid delivery device10.
• Thelocal processor50 of thedevice10 contains all the computer programs and electronic circuitry needed to allow a user to program the desired flow patterns and adjust the program as necessary. Such circuitry can include one or more microprocessors, digital and analog integrated circuits, resistors, capacitors, transistors and other semiconductors and other electronic components known to those skilled in the art. Thelocal processor50 also includes programming, electronic circuitry and memory to properly activate thedispenser40 at the needed time intervals.
• In the exemplary embodiment ofFIG. 2, thedevice10 includes apower supply80, such as a battery or capacitor, for supplying power to thelocal processor50. Thepower supply80 is preferably integrated into thefluid delivery device10, but can be provided as replaceable, e.g., a replaceable battery.
• Although not shown, thedevice10 can include sensors or transducers such as a reservoir volume transducer or a reservoir pressure transducer, for transmitting information to thelocal processor50 to indicate how and when to activate thedispenser40, or to indicate other parameters determining flow, blockage in flow path, contact sensors, rotary motion or other motion indicators, as well as conditions such as thereservoir30 being empty or leaking, or the dispensing of too much or too little fluid from the reservoir, etc.
• As shown inFIGS. 3 and 4, thedevice10 can also be provided with anadhesive layer22 on the outer surface of thehousing20 for securing thedevice10 directly to the skin of a patient, as illustrated inFIG. 1. Theadhesive layer22 is provided on an external “bottom” surface of thehousing20. The adhesive layer is also preferably provided in a continuous ring encircling theport24 of theexit port assembly70 in order to provide a protective seal around the penetrated skin to prevent the penetrated skin from becoming dirty when thecannula72 of theexit port assembly70 extends through the skin. It is preferably that thefill port90 extend through the bottom surface of thehousing20 and be surrounded by theadhesive layer22 to discourage and prevent filling and re-filling of thefluid delivery device10 when the device is attached to a patient's skin. Thehousing20 can be made from flexible material, or can be provided with flexible hinged sections that allow thefluid delivery device10 to flex during patient movement to prevent detachment and aid in patient comfort.
• In the exemplary embodiment ofFIGS. 4 and 5, thedevice10 is provided with anon-pressurized reservoir30, and thedispenser40 is adapted to control flow from thereservoir30 by driving or pumping the fluid from the reservoir to the exit port assembly.
• Examples of such “driving or pumping” dispensers are shown in co-pending U.S. patent application Ser. No. 09/955,623, filed on Sep. 19, 2001 (Atty. Docket No. INSL-117), and entitled PLUNGER FOR PATIENT INFUSION DEVICE, which is assigned to the assignee of the present application and incorporated herein by reference. Other examples of dispensers are shown in co-pending U.S. patent application Ser. No. 10/128,205, filed on Apr. 23, 2002 (Atty. Docket No. INSL-122), and entitled DISPENSER FOR PATIENT INFUSION DEVICE, which is assigned to the assignee of the present application and incorporated herein by reference, and co-pending U.S. patent application Ser. No. 10/128,203, filed on Apr. 23, 2002 (Atty. Docket No. INSL-123), and entitled DISPENSER FOR PATIENT INFUSION DEVICE, which is assigned to the assignee of the present application and incorporated herein by reference. Further examples of dispensers are shown in co-pending U.S. patent application Ser. No. ______, filed on Jun. 9, 2002 (Atty. Docket No. INSL-124), and entitled PLUNGER FOR PATIENT INFUSION DEVICE, which is assigned to the assignee of the present application and incorporated herein by reference, and in co-pending U.S. patent application Ser. No. ______, filed on Jun. 9, 2002 (Atty. Docket No. INSL-125), and entitled PLUNGER FOR PATIENT INFUSION DEVICE, which is also assigned to the assignee of the present application and incorporated herein by reference.
• In the embodiment shown inFIGS. 4 and 5, thereservoir30 includes aside wall32 extending towards anoutlet36 connected to theexit port assembly70. A threadedlead screw42 is received in thereservoir30 and extends towards theoutlet36 of thereservoir30 generally parallel with theside wall32 of the reservoir, and aplunger44 is secured to an end of thelead screw42. Thelead screw42, theplunger44 and thereservoir30 are adapted such that a fluid-tight seal is formed between the plunger and the lead screw and a fluid-tight seal is formed between the plunger and theside wall32 of the reservoir, so that movement of the plunger towards theoutlet36 of thereservoir30 forces fluid through theoutlet36 to theexit port assembly70.
• Thedispenser40 causes fluid flow by causing linear movement of thelead screw42 and theplunger44 towards theoutlet36 of thereservoir30. Although not shown, thedispenser40 can include an elongated shape memory element connected to thelocal processor50 and having a changeable length decreasing from an uncharged length to a charged length when at least one charge is applied to the shape memory element. The shape memory element is operatively connected to theplunger44 such that the changeable length of the shape memory element causes theplunger44 to move along theside wall32 of thereservoir30.
• In the embodiment shown, thedispenser40 includes arotatable gear46 linearly fixed with respect to thereservoir30. Thegear46 is coaxially mounted with respect to thelead screw42, and is threadedly engaged with thelead screw42, such that rotation of thegear46 causes linear movement of thelead screw42. In particular, thelead screw42 and thegear46 are adapted such that rotation of thegear46 in a first direction causes linear movement of thelead screw42 and theplunger44 towards theoutlet36 of thereservoir30.
• Thedispenser40 further includes afinger48 for engaging radially extending teeth of thegear46, wherein thefinger48 and thegear46 are adapted such that linear movement of thefinger48 in a first direction adjacent thegear46 causes rotation of the gear while linear movement of thefinger48 in a second direction adjacent thegear46 causes no rotation of the gear. Although not shown, the elongated shape memory element is connected to thefinger48 such that the changeable length of the shape memory element decreasing from an uncharged length to a charged length causes linear movement of thefinger48 in one of the first and the second directions. Thedispenser40 can also include an actuation element, such as a compression spring, connected to thefinger48 for causing linear movement of the finger in the first direction. Examples of such dispensers are shown in co-pending U.S. patent application Ser. No. 10/128,205, filed on Apr. 23, 2002 (Atty. Docket No. INSL-122), which has already been incorporated herein by reference.
• Although not shown, thegear46 can be further configured to be released from thelead screw42 to allow thelead screw42 and theplunger44 to be linearly moved away from theoutlet36 of thereservoir30 during filling of the reservoir. An example of such a releasable gear is also shown in co-pending U.S. patent application Ser. No. 10/128,205, filed on Apr. 23, 2002 (Atty. Docket No. INSL-122), which has already been incorporated herein by reference.
• It should be understood, however, that other types of dispensers can also be used with a device incorporating aflow restriction assembly200 of the present invention. For example, the device can be provided with a pressurized reservoir and a dispenser that does not create a driving or pumping force, but rather acts as a metering device, allowing pulses of fluid to pass from the pressurized reservoir, through the dispenser, to theexit port assembly70. Examples of such “metering” dispensers are shown in co-pending U.S. patent application Ser. No. 09/977,434, filed Oct. 12, 2001 (Atty. Docket No. INSL-116), and entitled LAMINATED PATIENT INFUSION DEVICE, which is assigned to the assignee of the present application and incorporated herein by reference. In any event, the dispenser is controlled by thelocal processor50, which includes electronic programming, controls, and circuitry to allow sophisticated fluid delivery programming and control of the dispenser.
• Referring now toFIGS. 2 through 4, an exemplary embodiment of theflow restriction system200 of the present invention is shown. Theflow restriction system200 generally includes an air removal filter communicating with theflow path12 and allowing air to exit theflow path12 and preventing fluid from exiting theflow path12, and a flow restrictor positioned within theflow path12 between the air removal filter and the exit port assembly70 (i.e., downstream of the filter). Among other features and advantages, theflow restriction system200 of the present invention allows theflow path12 of thefluid delivery device10 to be purged of air, or “primed” prior to operation, such that desired volumes of fluid can be accurately delivered by thedevice10. In particular, the air removal filter of theflow restriction system200 removes air from theflow path12, while the flow restrictor of theflow restriction system200 elevates pressure within theflow path12 to ensure that substantially all air within theflow path12 is forced out of the air removal filter.
• In the exemplary embodiment ofFIGS. 2 through 4, the flow restrictor and the air removal filter of theflow restriction system200 are combined in asingle outlet plug202 fitted to theport24 of theexit port assembly70. Theoutlet plug202 is unitarily formed of a material that allows the passage of air but prevents the passage of fluid, such as an ultrahigh molecular weight polyethylene in sinstered porous form, a porous ceramic, a hydrophobic gel, a woven or non-woven polytetrafluoroethylene (PTFE) such as Teflon®, or woven fabric material having very small openings (e.g., 0.02 microns) such as Gortex®.
• In the exemplary embodiment ofFIGS. 2 through 4, the flow restrictor and the air removal filter of theflow restriction system200 are positioned between thereservoir30 and theoutlet port assembly70. However, the flow restrictor and the air removal filter of theflow restriction system200 could be positioned before thereservoir30, as long as the flow restrictor is positioned downstream of the air removal filter.
• Theremovable outlet plug202 prevents fluid leakage from theflow path12 prior to use, e.g., during storage and during priming when filled by a user. Theoutlet plug202 may also maintain thecannula72 of theexit port assembly70 in a sterile state prior to use. Theoutlet plug202 is removed by a user prior to attaching thefluid delivery device10 to a patient's skin surface. In the embodiment shown, thecannula72 of theexit port assembly70 is extendable through theport22 in thehousing20 of thefluid delivery device10 to be inserted into the skin of a patient. Theoutlet plug202 is removably secured to the outer surface of thehousing20 over theport22, such that theoutlet plug202 prevents fluid from exiting theflow path12.
• FIG. 5 shows another exemplary embodiment of afluid delivery device10 including aflow restriction system300 constructed in accordance with the present invention. Thesystem300 ofFIG. 5 is similar to thesystem200 ofFIGS. 2 through 4 such that similar elements have the same reference numeral. Theflow restriction system300 ofFIG. 5, however, further includes aflow sensor assembly310 that provides an indication of fluid pressure within theflow path12, so that conditions within theflow path12 can be determined during a filling process. In particular, theflow sensor assembly310 can be used to provide an indication of when theflow path12 is full and when theflow path12 becomes primed.
• In the exemplary embodiment, as also shown inFIG. 5a, theflow sensor assembly310 comprises aresilient diaphragm320 having opposing first andsecond surfaces322,324, with thefirst surface322 positioned against theflow path12 of thedevice10, and achamber wall326 positioned adjacent thesecond surface324 of the diaphragm. Thediaphragm320 is made from a suitably expandable yet resilient material, such as rubber or a synthetic rubber. Thechamber wall326 is adapted such that anenclosed chamber328 is defined between thechamber wall326 and thesecond surface324 of thediaphragm320. Preferably, thechamber328 is provided with a predetermined volume. Although not shown, thechamber328 can also be provided with a relief port for allowing air to escape the chamber upon expansion of thediaphragm320.
• Thediaphragm320 and thechamber328 are arranged and adapted such that the amount of expansion and the duration of the expansion of the diaphragm into the chamber can be used to determine when theflow path12 becomes substantially primed upon being filled through thefill port90. Thesensor assembly310 also includes at least onesensor330 arranged to provide a signal when thesecond surface324 of thediaphragm320 expands into thechamber328 in response to at least one predetermined fluid flow condition occurring in theflow path12. For example, thesensor330 can be arranged to determine when thesecond surface324 of thediaphragm320 expands fully into thechamber328 and contacts thechamber wall326.
• Thesensor330 can comprise any device for determining and providing an indication of the position of thediaphragm320 in thechamber328. For example, the sensor can comprise one of a contact or pressure switch, a magnetic Hall effect sensor, a strain gage, and a density gage. In the embodiment ofFIG. 5a, the sensor comprises three open circuits330a,330b,330c, which each have their own primary leads332a,332b,332cand share asecondary lead334. Thesecondary lead334 is positioned on thesecond surface324 of thediaphragm320, while the primary leads332a,332b,332care positioned on thechamber wall326 at different points from thediaphragm320. During expansion of thediaphragm320 into thechamber328, thesecondary lead334 of thediaphragm320 eventually contacts each ofprimary leads332a,332b,332c, and successively closes the circuits330a,330b,330c.
• In theembodiment300 of the invention illustrated inFIGS. 2, theprocessor50 of thefluid delivery device10 also acts as the processor for thesensor assembly300 and is connected to the open circuits330a,330b,330c. During expansion of thediaphragm320 into thechamber328, the circuits330a,330b,330care successively closed to provide “signals” to theprocessor50. Alternatively, thesensor assembly300 can be provided with its own, separate processor programmed to operate in accordance with the present invention. In addition, the sensors330a,330b,330ccan simply be connected to an alarm(s), such as a light emitting diode or an electronic sound maker, and which is activated upon the circuits330a,330b,330cbeing closed. In this manner, a user can simply receive a visual or an audible alarm signal upon full expansion of thediaphragm320 into thechamber328 to close the circuits330a,330b,330c.
• FIG. 6 illustrates an exemplary embodiment of a method of determining when theflow path12 is primed in accordance with the present invention and as carried out by theprocessor50.FIG. 6 is a graph of pressure versus time illustrating pressure within the flow path while the flow path is being filled by a user. The pressure level “a” illustrated in the graph is produced upon thesecond surface324 of thediaphragm320 expanding partly into thechamber328 and closing the first sensor circuit330a, shown inFIG. 5a.Upon receiving signal “a” from the first sensor circuit330a, theprocessor50 is programmed to send a signal to theremote control device100 indicating that theflow delivery device10 is being filled. Although not shown, theremote control device100 can include an alarm, such as an audible or visual alarm, that the remote processor of theremote control device100 activates upon receiving the signal from thelocal processor50. In addition, thefluid delivery device10 itself can be provided with an alarm, such as a light emitting diode or electronic buzzer, connected to thelocal processor50 for activation at least initially when the flow path is being filled by a user.
• The pressure level “b” illustrated in the graph is produced upon thesecond surface324 of thediaphragm320 further expanding into thechamber328 and closing the second sensor circuit330b.Upon receiving signal “b” from the second sensor circuit330b, theprocessor50 is programmed to send a signal to theremote control device100 indicating that theplunger44 of theflow delivery device10 has been fully moved rearward within thereservoir30 and away from theoutlet36 of the reservoir. Although not shown, theremote control device100 can include another alarm, such as an audible or visual alarm, that the remote processor of theremote control device100 activates upon receiving the signal from thelocal processor50. In addition, thefluid delivery device10 itself can be provided with an alarm, such as a light emitting diode or electronic buzzer, connected to thelocal processor50 for activation when theplunger44 has been fully moved rearward within thereservoir30.
• The pressure level “c” illustrated in the graph is produced upon thethird surface324 of thediaphragm320 fully expanding into thechamber328 and closing the third sensor circuit330c.Upon receiving signal “c” from the third sensor circuit330c, theprocessor50 is programmed to send a signal to theremote control device100 indicating that theflow path12 is filled and primed. Although not shown, theremote control device100 can include another alarm, such as an audible or visual alarm, that the remote processor of theremote control device100 activates upon receiving the signal from thelocal processor50. In addition, thefluid delivery device10 itself can be provided with an alarm, such as a light emitting diode or electronic buzzer, connected to thelocal processor50 for activation when the flow path is primed.
• The preferred volume of thechamber328 should take into account the compliance of theentire flow path12 of thedevice10. At relative filling pressures, theflow path12 may expand, thereby artificially adding to the volume of thesensor chamber328. Any such artificially expanded volume must be taken into account in monitoring the signals received from the sensor. Preferably, theflow path12 is designed to have minimal compliance at both normal operating pressures and abnormal operating pressures. If minimal compliance of theflow path12 is not possible, however, the computer algorithm of the processor can be programmed to take the known compliance of theflow path12 into account when determining flow conditions based upon signals received from thesensor assembly310.
• Preferably, theflow path12 as well as thesensor assembly310 is constructed from laminated layers of suitably strong and rigid material such as plastic or stainless steel, and can be secured together in a suitable manner, such as with adhesives or by welding. The laminated construction provides many benefits including, but not limited to, simplifying the design and manufacturing of theflow path12 and thesensor assembly310, and further reducing the size, complexity and costs of thefluid delivery device10, so that the device lends itself to being small and disposable in nature.
• In alternative embodiments, thediaphragm320 of theflow sensor assembly310 can be provided as other than a flat layer of resiliently expandable material. The diaphragm can include any structure that provides a fluid-tight barrier between theflow path12 and thesensor chamber328, and that moves into the chamber upon an increase in pressure in theflow path12. For example, the diaphragm may be provided as a piston biased away from the chamber wall with a spring. Many alternative embodiments of the diaphragm are possible while remaining within the scope of the present invention. Examples of flow sensor assemblies are shown in co-pending U.S. patent application Ser. No. 10/087,507, filed on Mar. 1, 2002 (Atty. Docket No. INSL-118), and entitled FLOW CONDITION SENSOR ASSEMBLY FOR PATIENT INFUSION DEVICE, which is assigned to the assignee of the present application and incorporated herein by reference. Moreover, in alternative embodiments of the present invention, the flow sensor assembly can be provided in the form of a simple pressure sensor for determining when theflow path12 reaches a primed pressure.
• FIGS. 7 and 8 show another exemplary embodiment of a flow restriction system constructed in accordance with the present invention. Thesystem400 ofFIGS. 7 and 8 is similar to thesystem300 ofFIG. 5 such that similar elements have the same reference numeral. Theflow restriction system400 ofFIGS. 7 and 8, however, further includes a secondair removal filter402 positioned between thefill port90 and thereservoir30. Thefill port90 can include a resealingneedle insertion septum92 for receiving a needle and which can be constructed of a resealing elastomer such as silicone that allows a needle to puncture the septum to add fluid to thereservoir30 through thefill port90, yet reseals after the needle is withdrawn. Alternatively, thefill port90 can include a Luer or other connector.
• The second air removal filter is a flat sheet positioned in theflow path12 just after thefill port90, and can be comprised of any material for filtering air from fluid, such as an ultrahigh molecular weight polyethylene in sintered porous form, porous ceramic, hydrophobic gel, a woven or non-woven polytetrafluoroethylene (PTFE) such as Teflon®, woven fabric material having very small openings (e.g., 0.02 microns) such as Goretex®, or hydrophilic material that swells with fluid pressure. Theflow path12 includes anair escape port404 extending from thefilter402 for allowing filtered air to be directed out of theflow path12.
• In the exemplary embodiment ofFIGS. 7 and 8, theflow restriction system400 also includes asecond flow restrictor406 positioned between the secondair removal filter402 and thereservoir30. The second flow restrictor comprises a narrowedportion406 of theflow path12 and elevates pressure within theflow path12 to ensure that the secondair removal filter402 operates efficiently in removing air from fluid (e.g., insulin) injected into theflow path12 through thefill port90.
• In the exemplary embodiment ofFIGS. 7 and 8, thesensor assembly310 is positioned at the end of thereservoir30. Positioning thesensor assembly310 at the end of thereservoir30 can simplify the manufacturing process of thesensor assembly310 and thefluid delivery device10 and can reduce the number of parts to be assembled.
• FIG. 11 shows another exemplary embodiment of aflow restriction system420 constructed in accordance with the present invention. Thesystem420 ofFIG. 11 is similar to thesystem400 ofFIGS. 7 and 8 such that similar elements have the same reference numeral. Theflow restriction system420 ofFIG. 11, however, includes a second flow restrictor comprising aporous plug426 fitted in theflow path12 to elevate pressure within theflow path12 and ensure that the secondair removal filter402 operates efficiently in removing air from fluid (e.g., insulin) injected into the flow path through thefill port90.
• FIG. 9 shows an exemplary embodiment of anoutlet plug430 constructed in accordance with the present invention. Theoutlet plug430 is adapted to be received on aneedle72 of anoutlet port assembly70 of a fluid delivery device. Theoutlet plug430 includes asleeve432 having a first end removably received in a substantially fluid-tight manner on the distal end of theneedle72, and acap434 connected to a second end of thesleeve432. In the embodiment shown, thesleeve432 and thecap434 of theoutlet plug430 are unitarily formed from a resiliently flexible material, such as a synthetic rubber. Anair removal filter436 is seated in thecap434 of theoutlet plug430 and prevents fluid from passing out of theneedle72 and allows air to pass out of theneedle72. As shown inFIGS. 10aand10b, theair removal filter436 is provided with predetermined physical properties, such as material pore size and/or thickness, such that thefilter436 expands upon the flow path being substantially primed.
• Theair removal filter436 can additionally be provided with specific visual indicia for indicating when the flow path is substantially primed. For example,FIGS. 15aand15b, show an exemplary embodiment of theoutlet plug430 wherein the visual indicia comprises a drawing on thefilter436 that changes shape upon the filter expanding. For example, the drawing can comprise two eyes and a mouth that appear as a “sad face” when thefilter436 is not expanded, as shown inFIG. 15a, and that become a “happy face” upon thefilter436 expanding when the flow path is primed, as shown inFIG. 15b.Other drawings can alternatively be used to provide an effective indication offilter436 expansion and the flow path becoming primed.
• FIGS. 16aand16bshow another exemplary embodiment of anoutlet plug440 constructed in accordance with the present invention. Theplug440 ofFIGS. 16aand16bis similar to theplug430 ofFIGS. 9, 10aand10b, such that similar elements have the same reference numeral. Theoutlet plug440 ofFIGS. 16aand16b, however, includes an air removal filter having anouter layer436aand an inner layer436b.The inner layer436bhas predetermined physical properties, such as material pore size and/or thickness, that allows the inner layer436bto expand to contact theouter layer436aupon the flow path becoming substantially primed. Theouter layer436aof theair removal filter440 is relatively transparent and the inner layer436bis darker in coloring than the outertransparent layer436asuch that the inner layer436bcan be seen through theouter layer436awhen the inner layer contacts the outer layer. Alternatively, the flow restriction system can be provided with a sensor, such as a contact sensor, for providing a signal when the inner layer436bcontacts theouter layer436a.
• FIG. 12 shows another exemplary embodiment of anoutlet plug450 constructed in accordance with the present invention. Theplug450 ofFIG. 12 is similar to theplug430 ofFIGS. 9, 10aand10b, such that similar elements have the same reference numeral. Theoutlet plug450 ofFIG. 12, however, includes anair removal filter452 that is comprised of a material that also acts as a needle septum such that theexit port assembly70 of thefluid delivery device10 can also act as the fill port for thedevice10. For example,FIG. 12 shows theair removal filter452 receiving aneedle454 of asyringe456 for filling the flow path of thedevice10. Theoutlet plug450, therefore, functions as an air removal filter, a flow restrictor and a needle septum. In this manner, thefluid delivery device10 is further simplified since it does not require a separate fill port.
• FIG. 13 shows an additional exemplary embodiment of anoutlet plug460 constructed in accordance with the present invention. Theplug460 ofFIG. 13 is similar to theplug430 ofFIGS. 9, 10aand10b, such that similar elements have the same reference numeral. Theoutlet plug460 ofFIG. 13, however, includes acap462 further including straps462afor securely holding theair removal filter436 therein.
• FIG. 14 shows still another exemplary embodiment of anoutlet plug470 constructed in accordance with the present invention. Theplug470 ofFIG. 14 is similar to theplug430 ofFIGS. 9, 10aand10b, such that similar elements have the same reference numeral. Theoutlet plug470 ofFIG. 14, however, further includes apressure relief valve472. Therelief valve472 ensures that pressure within the flow path of the fluid delivery device does not become excessive during a filling procedure, i.e., does not exceed a desired maximum level of flow path pressure, which could damage the fluid delivery device. Alternatively, theair removal filter436 of the outlet plug can be adapted to allow fluid to pass out of theneedle72 upon a pressure within the flow path exceeding a desired maximum level of flow path pressure. The fluid leaking from theneedle72 would then act as a visual indication to a user that the fluid delivery device was improperly filled and should be discarded prior to use.
• Referring now toFIG. 17, a further exemplary embodiment of anoutlet plug480 constructed in accordance with the present invention is shown. Theplug480 ofFIG. 17 may be configured to act only as a flow restrictor (wherein the system would include a separate air removal filter within the flow path of the device10) or may be configured to act as both the flow restrictor and the air removal filter. In any event, theoutlet plug480 ofFIG. 17 also includes ahandle482 for supporting thefluid delivery device10 during filling of the device through the fill port. Thehandle482 of theoutlet plug480 preferably includes anouter contour484 that nests with an outer contour of an end thefluid delivery device10, as shown inFIG. 17.
• FIG. 18 shows another exemplary embodiment of anoutlet plug490 constructed in accordance with the present invention. Theoutlet plug490 ofFIG. 18 also includes ahandle492 for supporting thefluid delivery device10 during filling of the device. Thehandle492 of theoutlet plug490 includes anouter contour494 that nests with an outer contour of an end of thefluid delivery device10. Thehandle494 also includes anextension496 that supports a top surface of thefluid delivery device10 during filling of the device.
• An exemplary embodiment of apackaging system500 constructed in accordance with the present invention is shown inFIG. 19. Thepackaging system500 includes acontainer502 holding the fluid delivery device10 (e.g., similar to thefluid delivery device10 ofFIGS. 2 through 4), and aprotective cover504 removably sealing thefluid delivery device10 within thecontainer502. Thecontainer502 includes aninner contour506 that nests with an outer contour of thefluid delivery device10 to provide support for thedevice10 during handling and storage of thepackage system500 and during filling of thedevice10 by a user. The outlet plug202 (e.g., similar to the outlet plug ofFIGS. 2 through 4) of the flow restriction system is secured to and extends through theprotective cover504, so that thefluid delivery device10 can be filled while thedevice10 is still sealed in thecontainer502 and thecover504. In addition, removal of theprotective cover504 from thecontainer502 removes the outlet plug202 from theexit port assembly70. Thefluid delivery device10 also includes aswitch mechanism508, and theprotective cover504 includes aninsert510 extending into thefluid delivery device10 to normally hold theswitch mechanism508 open. Upon removal of thecover504, theinsert510 is removed from theswitch mechanism508 such that theswitch mechanism508 can close. Theswitch mechanism508 can be used, example, to turn on the processor of thefluid delivery device10 just prior to thedevice10 being attached to a patient.
• FIGS. 20aand20bshow yet a further exemplary embodiment of aflow restriction system520 and afluid delivery device530 constructed in accordance with the present invention. Thesystem520 and thefluid delivery device530 ofFIGS. 20aand20bare similar to thesystem200 and thedevice10 ofFIGS. 2 through 4 such that similar elements have the same reference numeral.
• Thefluid delivery device530 ofFIGS. 20 and 20bincludes anadhesive layer22 on a bottom external surface of thehousing20 for securing thedevice530 to a patient, and a removableprotective layer26 covering theadhesive layer22 prior to attachment of thefluid delivery device530 to a patient. Theflow restriction system520 includes anoutlet plug202 that acts as both a flow restrictor and an air removal filter for thesystem520, and is secured to aninsertable cannula72 of theexit port assembly70 prior to attachment of thefluid delivery device530 to a patient. Theoutlet plug202 is secured to theprotective layer26 of thefluid delivery device530 so that theplug202 is also removed from thecannula72 when theprotective layer26 is removed from theadhesive layer22 for attachment of thefluid delivery device530 to a patient.FIG. 20ashows theprotective layer26 and theoutlet plug202 prior to removal from thefluid delivery device530, whileFIG. 20bshows theprotective layer26 and theoutlet plug202 after removal from thefluid delivery device530.
• Thefluid delivery device530 also includes aswitch mechanism532 for providing an indication when theoutlet plug202 is removed from the distal end of thecannula72. Theswitch mechanism532 can be connected, for example, to the processor (not shown) of thefluid delivery device530 to provide an indication that theoutlet plug202 has been removed, or can be connected to an alarm, such as an LED, for providing an indication to a user that theoutlet plug202 has been removed. Theswitch mechanism532 can also be used to turn on the fluid delivery device530 (e.g., connect the power source to the processor) upon removal of theoutlet plug202.
• In the exemplary embodiment shown inFIGS. 20aand20b, theswitch mechanism532 includes afirst lead534 normally biased towards asecond lead536 to close the switch mechanism. Theswitch mechanism532 is arranged and oriented with respect to theoutlet port assembly70 such that theoutlet plug202 pushes thefirst lead534 away from thesecond lead536 when theoutlet plug202 is positioned on thecannula72, as shown inFIG. 20a.When theoutlet plug202 is removed from the distal end of thecannula72, thefirst lead534 is allowed to return to thesecond lead536 and close theswitch mechanism532, as shown inFIG. 20b.
• Additional exemplary embodiments of aflow restriction system540 and aflow path550 of a fluid delivery device constructed in accordance with the present invention are shown inFIG. 21. Thesystem540 and theflow path550 ofFIG. 21 are similar to thesystem200 and theflow path12 ofFIGS. 2 through 4 such that similar elements have the same reference numeral. Theflow path550 includes an outlet port assembly comprising a rigid cannula72 (e.g., a needle with sharpened distal end), areservoir30 connected to thecannula72, and a fill port comprising aneedle septum90 connected to thereservoir30.
• Theflow restriction system540 includes anair removal filter542 positioned in theflow path550 between thereservoir30 and thefill port90, and anoutlet plug544 removably fitted on the sharpened distal end of therigid cannula72. Theoutlet plug544 is made of a suitable air removal filter material such that the outlet plug544 functions as both an air removal filter and a flow restrictor. Theoutlet plug544 causes an increased pressure within theflow path550 during filling of the flow path through the fill port90 (with a needle and syringe, for example), so that air can be effectively filtered through theair removal filter542 and theoutlet plug544. Theoutlet plug544 is removed from thecannula72 prior to use of the flow path530 (i.e., prior to injection of the cannula into a patient for delivery of fluid contained in the reservoir).
• FIG. 22 shows another exemplary embodiment of anoutlet plug560 constructed in accordance with the present invention. Theoutlet plug560 is formed as part of aprotective layer562 removably attached to anadhesive layer22 of thefluid delivery device10. The exemplary embodiment of thefluid delivery device10 ofFIG. 22 includes anexit port assembly570 having aninjectable needle572 for insertion into a patient. Theneedle572 is extendable out of aport24 in ahousing20 of thefluid delivery device10. An o-ring574 provides a fluid tight seal between theport24 and theneedle572. Theoutlet plug560 provides a substantially fluid-tight seal of theport24 when theprotective layer562 is attached to the adhesive22. Theoutlet plug560 is made of a suitable air removal filter material such that the outlet plug560 functions as both an air removal filter and a flow restrictor. In the embodiment shown, theoutlet plug560 is made of a different material than the remainder of theprotective layer562. The remainder of theprotective layer562 is made of a suitable material that readily detaches from theadhesive layer22, such as wax paper or a plastic. Alternatively, the protective layer can be made entirely of a suitable air removal filter material that is also readily detachable from theadhesive layer22, such that the portion of the protective layer positioned over theport24 of thehousing20 can act as the outlet plug.
• FIGS. 23 and 26 show yet a further exemplary embodiment of aflow restriction system600 and afluid delivery device610 constructed in accordance with the present invention. Thesystem600 and thefluid delivery device610 ofFIGS. 23 and 26 are similar to thesystem200 and thedevice10 ofFIGS. 2 through 4 such that similar elements have the same reference numeral.
• Aflow path612 of thefluid delivery device610 includes areservoir630 and anoutlet port assembly670 terminating in aneedle672 for insertion into a patient. Theneedle672 is extendable out of aport624 in ahousing620 of thefluid delivery device610. An o-ring674 provides a fluid tight seal between theport624 and theneedle672. Theoutlet port assembly670 also includes aninjection mechanism676 for injecting theneedle672 into a patient. Theflow path612 does not require a separate fill port connected to thereservoir630, as further discussed below.
• Theflow restriction system600 includes an air removal filter and a flow restrictor combined in asingle outlet plug602 fitted to the end of theexit port assembly670, as also shown inFIG. 27. Theflow restriction system600 further includes aflow sensor assembly330 positioned at the end of thereservoir630, as also shown inFIG. 24. A secondair removal filter604 is positioned between thereservoir630 and theexit port assembly670 and can be adapted to also function as a second flow restrictor if desired.
• Theremovable outlet plug602 is fitted to the end of theexit port assembly670 and prevents fluid leakage from theflow path612 prior to use, e.g., during storage and during priming when filled by a user. Theoutlet plug602 is removed by a user prior to attaching thefluid delivery device610 to a patient's skin surface. Also referring toFIG. 25, theoutlet plug602 includes asleeve605 having a first end removably received in a substantially fluid-tight manner on the distal end of theneedle672, and acap607 connected to a second end of thesleeve605. In the embodiment shown, thesleeve605 and thecap607 of theoutlet plug602 are unitarily formed from a resiliently flexible material. Anair removal filter606 is seated in thecap607 such that air passing through thefilter606 can exit theoutlet plug602 through anair release port609 in thecap607. Theair removal filter606 also acts as the flow restrictor.
• Theoutlet plug602 further includes aneedle septum692. Theoutlet plug602, therefore, functions as an air removal filter, a flow restrictor and a needle septum. In this manner, thefluid delivery device610 is further simplified since it does not require a separate fill port.
• As illustrated by the above described exemplary embodiments, the present invention generally provides a device for delivering fluid, such as insulin for example, to a patient. The device includes a flow path having an exit port assembly adapted to connect to a transcutaneous patient access tool (e.g., needle), and a reservoir connected to the exit port assembly. The device also includes a flow restriction system having an air removal filter communicating with the flow path and allowing air to exit the flow path and preventing fluid from exiting the flow path, and a flow restrictor positioned within the flow path between the air removal filter and the exit port assembly.
• Among other features and advantages, the flow restriction system of the present invention allows the flow path of the fluid delivery device to be purged of air, or “primed” prior to operation, such that desired volumes of fluid can be accurately delivered by the device.
• It should be understood that the embodiments described herein are merely exemplary and that a person skilled in the art may make variations and modifications to the embodiments described without departing from the spirit and scope of the present invention. All such equivalent variations and modifications are intended to be included within the scope of this invention as defined by the appended claims.

Claims (21)

1. A device for delivering fluid to a patient, comprising:

A) a flow path including,

an exit port assembly adapted to connect to a transcutaneous patient access tool, and

a reservoir connected to the exit port assembly; and

B) a flow restriction system including,

an air removal filter communicating with the flow path and allowing air to exit the flow path and preventing fluid from exiting the flow path, and

a flow restrictor positioned within the flow path between the air removal filter and the exit port assembly;

wherein,

the flow restrictor of the flow restriction system comprises an outlet plug removably connected to the exit port assembly to prevent fluid from exiting the flow path through the exit port assembly;

the exit port assembly includes a transcutaneous patient access tool comprising a needle having a distal end for insertion into a patient and the outlet plug comprises:

a sleeve having a first end removably received in a substantially fluid-tight manner on the distal end of the needle; and

a cap connected to a second end of the sleeve.

2. A device according toclaim 1, wherein the sleeve and the cap of the outlet plug are unitarily formed from a resiliently flexible material.

3. A device according toclaim 1, wherein the air removal filter is seated in the cap of the outlet plug and prevents fluid from passing out of the needle and allows air to pass out of the needle.

4. A device according toclaim 3, wherein the air removal filter of the outlet plug comprises one of PTFE and polyethylene.

5. A device according toclaim 3, wherein the air removal filter of the outlet plug is provided with predetermined physical properties such that the filter expands upon the flow path being substantially primed.

6. A device according toclaim 5, wherein the air removal filter includes visual indicia for indicating when the flow path is substantially primed.

7. A device according toclaim 6, wherein the visual indicia comprises a drawing on the filter that changes shape upon the filter expanding.

8. A device according toclaim 3, wherein the air removal filter of the outlet plug is adapted to allow fluid to pass out of the needle upon a pressure within the flow path exceeding a desired maximum level of flow path pressure.

9. A device according toclaim 3, wherein the air removal filter of the outlet plug includes:

an outer layer; and

an inner layer having predetermined physical properties that allow the inner layer to expand to contact the outer layer upon the flow path being substantially primed.

10. A device according toclaim 9, wherein the outer layer of the air removal filter is relatively transparent and the inner layer of the air removal filter is darker in coloring than the outer transparent layer such that the inner layer can be seen through the outer layer when the inner layer contacts the outer layer.

11. A device according toclaim 9, wherein the flow restriction system further includes a filter sensor for providing a signal when the inner layer contacts the outer layer.

12. A device according toclaim 3, wherein the air bubble removal filter of the outlet plug is comprised of needle septum material.

13. A device for delivering fluid to a patient, comprising:

A) a flow path including,

an exit port assembly adapted to connect to a transcutaneous patient access tool, and

a reservoir connected to the exit port assembly; and

B) a flow restriction system including,

an air removal filter communicating with the flow path and allowing air to exit the flow path and preventing fluid from exiting the flow path, and

a flow restrictor positioned within the flow path between the air removal filter and the exit port assembly;

wherein,

the flow restrictor of the flow restriction system comprises an outlet plug removably connected to the exit port assembly to prevent fluid from exiting the flow path through the exit port assembly; and

the outlet plug further comprises a needle septum.

14. A device for delivering fluid to a patient, comprising:

A) a flow path including,

an exit port assembly adapted to connect to a transcutaneous patient access tool, and

a reservoir connected to the exit port assembly; and

B) a flow restriction system including,

an air removal filter communicating with the flow path and allowing air to exit the flow path and preventing fluid from exiting the flow path, and

a flow restrictor positioned within the flow path between the air removal filter and the exit port assembly;

wherein,

the flow restrictor of the flow restriction system comprises an outlet plug removably connected to the exit port assembly to prevent fluid from exiting the flow path through the exit port assembly; and

the outlet plug includes a pressure relief valve actuable upon a pressure within the flow path exceeding a desired maximum level of flow path pressure.

15. A device for delivering fluid to a patient, comprising:

A) a flow path including,

an exit port assembly adapted to connect to a transcutaneous patient access tool, and

a reservoir connected to the exit port assembly; and

B) a flow restriction system including,

an air removal filter communicating with the flow path and allowing air to exit the flow path and preventing fluid from exiting the flow path, and

a flow restrictor positioned within the flow path between the air removal filter and the exit port assembly;

wherein,

the flow restrictor of the flow restriction system comprises an outlet plug removably connected to the exit port assembly to prevent fluid from exiting the flow path through the exit port assembly; and

further comprising:

a housing containing the flow path, wherein the exit port assembly extends at least partly through a port in the housing;

an adhesive layer provided in at least one continuous band on an exterior surface of the housing surrounding the port of the housing; and

a protective layer removably covering the adhesive layer, wherein the outlet plug of the flow restriction system is secured to the protective layer so that removal of the protective layer removes the outlet plug from the exit port assembly.

16. A device for delivering fluid to a patient, comprising:

A) a flow path including,

an exit port assembly adapted to connect to a transcutaneous patient access tool, and

a reservoir connected to the exit port assembly; and

B) a flow restriction system including,

an air removal filter communicating with the flow path and allowing air to exit the flow path and preventing fluid from exiting the flow path, and

a flow restrictor positioned within the flow path between the air removal filter and the exit port assembly;

wherein,

the flow restrictor of the flow restriction system comprises an outlet plug removably connected to the exit port assembly to prevent fluid from exiting the flow path through the exit port assembly; and

further comprising a switch arranged to be closed upon removal of the outlet plug from the exit port assembly.

17. A device according toclaim 16, wherein the outlet plug includes a handle for supporting the fluid delivery device during filling of the device through the fill port.

18. A device according toclaim 17, wherein the handle of the outlet plug includes an outer contour that nests with an outer contour of the fluid delivery device.

19. A packaging system including a device according toclaim 16, and further including:

a container holding the fluid delivery device; and

a protective cover removably sealing the fluid delivery device within the container, wherein the outlet plug of the flow restriction system is secured to the protective cover so that removal of the protective cover from the container removes the outlet plug from the exit port assembly.

20. The packaging system ofclaim 19, wherein the container includes an inner contour that nests with an outer contour of the fluid delivery device.

21. The packaging system ofclaim 19, wherein the fluid delivery device includes a switch and the protective cover includes an insert extending into the fluid delivery device to normally hold the switch open.

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