US20020173769A1 - Infusion set for a fluid pump - Google Patents

Abstract

A medical device for delivery of a fluid to a patient from a line terminating in a tubing needle. The medical device includes a cannula assembly for coupling the fluid into a cannula that is inserted into the patient. The cannula assembly has a first locking element disposed in a fixed position with respect to the cannula. Coupling the line to the cannula assembly is an infusion flap. The infusion flap includes a second locking element for engaging the first locking element of the cannula assembly and a lift tab for disconnecting the infusion flap from the cannula assembly. Coupling of the first and second locking elements requires initial mating of the infusion flap and cannula assembly followed by locking through rotation of the infusion flap with respect to the cannula assembly.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• This application claims priority from U.S. provisional patent application serial No. 60/291,881, filed May 18, 2001, entitled “Cannula Designs for Insulin Pump Systems.” This application is a continuation-in-part of U.S. patent application Ser. No. 10/037,614, filed Jan. 4, 2002, entitled “Loading Mechanism for Infusion Pump.” Each of these patent applications described in this paragraph is hereby incorporated by reference, in its entirety.[0001]
TECHNICAL FIELD AND BACKGROUND ART
• The present invention relates to a system and method for delivery of a fluid to a patient, and more particularly, to an infusion set for a fluid pump that may be used, for example, to deliver insulin to a patient.[0002]
• Currently, there are two primary methods of treating diabetes. One method involves taking multiple injections of long acting insulin on a daily basis. The second method is by continuous delivery of short acting insulin to more closely emulate the human pancreas. This may be accomplished using a syringe pump.[0003]
• A syringe pump typically includes four major components. These components are a microprocessor controlled syringe pump, an insulin filled syringe, a hub and tubing set, and a cannula.[0004]
• A syringe pump is often worn in a carrying case on a patient's belt, in a manner similar to a pager, or in more discrete locations such as a pocket or a brassiere. The syringe is mounted in the syringe pump and may hold enough insulin for three days. The hub serves as an interface between the syringe and a tubing set. At the end of a tubing set is a cannula typically made of either steel or Teflon. The cannula may advantageously be carried in a cannula assembly. The cannula assembly typically attaches to the patient by adhesive and is placed near the abdomen around and to the side of the navel. The cannula is inserted in fatty tissue and the insulin is injected subcutaneously.[0005]
• A patient may perform activities that do not permit or are hindered by the presence of a pump, for example, when a patient wishes to take a shower or participate in certain athletic activities. Removing each of the components, including the cannula, would require a needle stick upon reconnecting the system to a patient. Since a needle stick is undesirable every time one wishes to take a shower or participate in sports, state of the art tubing sets disconnect at or near the cannula assembly, with the tubing capped to prevent contamination. Disconnecting and reconnecting the tubing set is sometimes difficult.[0006]
• Cannulas with steel subcutaneous needles have been used with syringe pumps for decades. Steel needles, however, can cause irritation and discomfort. Soft cannulas, which may be made of Teflon, for example, help prevent this discomfort and are generally known in the art. The soft cannula requires the use of a steel insertion needle to penetrate skin and/or other tissue. When inserting the needle, the needle penetrates a first self-sealing septum in the cannula housing. The needle is then pushed through the soft cannula until it extends through the cannula's outer tip. After insertion of the needle into the skin, the steel needle is removed and the first septum seals the opening where the insertion needle entered. The tubing set may then be connected to the cannula by inserting a tubing needle at the end of the tubing set into a second septum in the cannula housing.[0007]
• After removing the insertion needle, the first septum may be susceptible to leakage. This leakage may become more prevalent under pressure, such as when the cannula has an occlusion. Normally during an occlusion, the pressure will reach a threshold and trigger an alarm on the pump. However, if the first septum leaks, the pressure may never reach the threshold, and the pump may continue to deliver insulin. As a result, the insulin will continue to leak out of the first septum, the alarm will never trigger, and the user unknowingly does not receive the drug for an indefinite period of time.[0008]
SUMMARY OF THE INVENTION
• In a first embodiment of the invention there is provided a medical device for delivery of a fluid to a patient from a line terminating in a tubing needle. The medical device includes a cannula assembly for coupling the fluid into a cannula that is inserted into the patient. The cannula assembly has a first locking element disposed in a fixed position with respect to the cannula. Coupling the line to the cannula assembly is an infusion flap. The infusion flap includes a second locking element for engaging the first locking element of the cannula assembly and a lift tab for disconnecting the infusion flap from the cannula assembly. Coupling of the first and second locking elements requires initial mating of the infusion flap and cannula assembly, followed by locking through rotation of the infusion flap with respect to the cannula assembly.[0009]
• In a related embodiment, the cannula assembly may include a septum housing defining a core coupled to the cannula. The septum housing includes a first septum positioned within the core at a first position, such that when the infusion flap and the cannula assembly are locked, the tubing needle penetrates the first septum so as to permit fluid communication between the line and the cannula. The septum housing may also include a second septum positioned within the core at a second position, such that an insertion needle can be introduced through the second septum into the cannula.[0010]
• In another related embodiment of the invention, the cannula assembly further includes a flexible tube in fluid communication with both the cannula and a septum. When the flexible tube is in a first position, an insertion needle can be introduced through the septum into the cannula, and when the flexible tube is in a second position, a tubing needle inserted through the septum permits fluid communication between the line and the cannula.[0011]
• In yet another related embodiment of the invention, the device further includes an insertion flap. The insertion flap includes an insertion needle for inserting through the septum and terminating with a sharp distal end disposed slightly beyond a distal end of the cannula. The insertion flap has an interface for coupling to an auto-insertion device.[0012]
• In other related embodiments, the first locking element may be a locking lug and the second locking element is a lug receptacle, or vice versa. The cannula assembly may include a soft overmolded body.[0013]
• In accordance with another embodiment of the invention, a medical device for delivery of a fluid to a patient from a line terminating in a tubing needle is presented that includes a a cannula for insertion into the patient. A flexible tube is in fluid communication with both the cannula and a septum. When the flexible tube is in a first position, an insertion needle can be introduced through the septum into the cannula, and when the flexible tube is in a second position, a tubing needle inserted through the septum permits fluid communication between the line and the cannula.[0014]
• In accordance with related embodiments of the invention, the device further includes an infusion flap that includes the tubing needle and a cannula assembly that includes the cannula. When the infusion flap and cannula assembly are mated, the tubing needle passes through the septum permitting fluid communication between the line and the cannula. The device may further include a locking mechanism for securing the infusion flap to the cannula assembly. The locking mechanism may include a locking tang on the infusion flap, the locking tang inserted into a tang receptacle on the cannula assembly. As another example, the locking mechanism may include a first locking element disposed on a septum housing containing the septum, and a second locking element disposed on the infusion flap. Coupling the first and second locking elements may require initial mating of the infusion flap and cannula assembly followed by locking through rotation of the infusion flap with respect to the cannula assembly. In various embodiments, the first locking element is a locking lug and the second locking element is a lug receptacle, or vice versa. In various embodiments, the septum housing can be rotated to a mating position that allows the infusion flap and the septum housing to be mated together and the infusion flap rotated with respect to the cannula assembly to lock the infusion flap onto the septum housing. The septum housing can then be rotated to a stable position that prevents rotation of the infusion flap.[0015]
• In accordance with another embodiment of the invention, a method for delivering a fluid to a patient from a line terminating in a tubing needle is presented. The method includes inserting an insertion needle through a septum and a cannula, the septum and the cannula having a relative orientation. The cannula is inserted into tissue of a patient. After withdrawing the insertion needle from the cannula and the septum, a tubing needle is inserted through the septum. The relative orientation between the septum and the cannula is varied and the fluid is delivered through the line and the cannula.[0016]
• In accordance with still another embodiment of the invention, a tubing set for coupling a fluid delivery device containing a fluid source into fluid communication with a cannula assembly is presented. The tubing set includes a length of tubing having a first end and a second end. A hub is coupled to the first end for connecting to the fluid delivery device. The hub includes a controller which allows the fluid delivery device to transition from a first configuration to a second configuration. An infusion flap is coupled to the second end for connecting to the cannula assembly.[0017]
• In another related embodiment of the invention, the first configuration of the fluid delivery device may be a reservoir load position and the second configuration may be an operate position. The controller may be capable of allowing the fluid delivery device to transition from the second configuration to the first configuration. The controller may include a flange that interfaces with the fluid delivery device. In other embodiments, the controller may include an electronic circuit to the fluid delivery device, or generating one of an optical signal and magnetic field. The hub may include a luer connector for mating with the fluid delivery device.[0018]
• In another related embodiment of the invention, the fluid delivery device may be an infusion pump having a reservoir with variable volume and a drive assembly. The drive assembly includes a barrel having a clearance hole in a barrel end, the barrel characterized by a longitudinal barrel axis of rotation. The drive assembly further includes a plunger rod inserted through the clearance hole, and a rotating drive screw with external threads. The external threads removably engage with threads on the plunger rod by rotating the barrel about the barrel axis. The external threads are engaged with the threads on the plunger rod when in the first configuration and the external threads are disengaged with the threads on the plunger rod when in the second configuration. The controller is capable of allowing the barrel to rotate so as to bring the rod threads in and out of mechanical engagement with the drive screw threads. The controller may include a flange for dislodging a locking tab on the barrel, allowing the barrel to rotate.[0019]
• In accordance with still another embodiment of the invention, a conduit for coupling to a fluid delivery device is presented. The conduit includes a length of tubing having a first end. A hub is coupled to the first end for connecting to the fluid delivery device. The hub includes a controller which allows the fluid delivery device to transition from a first configuration to a second configuration.[0020]
• In related embodiments of the invention, the first configuration may be a reservoir load position and the second configuration may be an operate position. The hub may include a luer connector for mating with the fluid delivery device. The controller may include a flange that interfaces with the fluid delivery device. The controller may include an electronic circuit to the fluid delivery device, or generating one of an optical signal and magnetic field.[0021]
• In still yet another embodiment of the invention, a method of providing flow of a fluid from a fluid delivery device to a porous medium is presented. The method includes coupling a hub, permanently affixed to a tube set, to the fluid delivery device. Configuration of the fluid delivery device is controlled via the hub. The tube set is coupled to the porous medium so as to allow fluid to flow from the fluid delivery device to the porous medium.[0022]
• In related embodiments of the invention, controlling the configuration of the fluid delivery device may include allowing the pump to move from a first configuration to a second configuration. The first configuration of the fluid delivery device may be a load position and the second configuration may be an operate position. Controlling the configuration of the fluid delivery device may include moving a flange on the hub or generating one of a magnetic field and an optical signal. The fluid delivery device may be an infusion pump.[0023]
BRIEF DESCRIPTION OF THE DRAWINGS
• The foregoing features of the invention will be more readily understood by reference to the following detailed description, taken with reference to the accompanying drawings, in which:[0024]
• FIG. 1 is a perspective view of an infusion set[0025]10 for delivery of a fluid to a patient, in accordance with one embodiment of the present invention;
• FIG. 2 is a further breakdown of the infusion set shown in FIG. 1, in accordance with one embodiment of the present invention;[0026]
• FIG. 3 is a cross-sectional view of a cannula assembly with an insertion flap attached (and locked), in accordance with one embodiment of the present invention;[0027]
• FIG. 4 is a cross-sectional view of an infusion flap mated (and locked) to a cannula assembly, in accordance with one embodiment of the present invention;[0028]
• FIG. 5 is a side view of the embodiment of FIG. 4 with the infusion flap in position for mating with the cannula assembly;[0029]
• FIG. 6 is a perspective view of the embodiment of FIG. 4 with the infusion flap mated to the cannula assembly;[0030]
• FIG. 7 is a top view of the embodiment of FIG. 4 with the tubing set locked to the cannula assembly;[0031]
• FIG. 8 is a side view of the embodiment of FIG. 4 with the tubing set locked to the cannula assembly;[0032]
• FIG. 9 is a cross-sectional view of an infusion flap mated (and locked) to a cannula assembly that includes a first septum and a second septum contained with a septum housing, in accordance with one embodiment of the present invention;[0033]
• FIG. 10 is a top view of the embodiment of FIG. 9 with the infusion flap in position for mating with the cannula assembly;[0034]
• FIG. 11 is a side view of the embodiment of FIG. 9 with the infusion flap in position for mating with the cannula assembly;[0035]
• FIG. 12 is a perspective view of the embodiment of FIG. 9 with the infusion flap mated to the cannula assembly;[0036]
• FIG. 13 is a cross-sectional view of an infusion flap mated (and latched) to a cannula assembly, wherein the cannula assembly includes a single septum located in a rotatable septum housing, in accordance with one embodiment of the present invention;[0037]
• FIG. 14 is a perspective view of the embodiment of FIG. 13 with the infusion flap in position for mating with a cannula assembly;[0038]
• FIG. 15 is a side view of the embodiment of FIG. 13 with the infusion flap in position for mating with the cannula assembly;[0039]
• FIG. 16 is a perspective view of the embodiment of FIG. 13 with the infusion flap mated and latched onto the cannula assembly;[0040]
• FIG. 17 is a side view of the embodiment of FIG. 13 with the infusion flap mated and latched onto the cannula assembly;[0041]
• FIG. 18 is a perspective view of embodiment of FIG. 13, with the infusion flap latched to the septum housing and the septum housing rotated 90 degrees;[0042]
• FIG. 19 is a cross-sectional view of an infusion flap that includes a single septum located in a rotatable septum housing, in accordance with one embodiment of the invention;[0043]
• FIG. 20 is a perspective view of the embodiment of FIG. 19 with the infusion flap in position for mating with the cannula assembly;[0044]
• FIG. 21 is a top view of the embodiment of FIG. 19 with the infusion flap in position for mating with the cannula assembly;[0045]
• FIG. 22 is a side view of the embodiment of FIG. 19 with the infusion flap in position for mating with the cannula assembly;[0046]
• FIG. 23 is a perspective view of the embodiment of FIG. 19 with the infusion flap mated with the[0047]cannula assembly1902;
• FIG. 24 is a side view of the embodiment of FIG. 19 with the infusion flap mated with the[0048]cannula assembly1902;
• FIG. 25 is a perspective view of the embodiment of FIG. 19 with the locking lug engaged with the lug receptacle by rotating the[0049]infusion flap25;
• FIG. 26 is a perspective view of the embodiment of FIG. 19 after the locking lug is engaged with the lug receptacle and the[0050]septum housing1904 is rotated;
• FIG. 27 is a top-level view of a hub and infusion pump, in accordance with one embodiment of the present invention;[0051]
• FIG. 28 is an exploded view of a drive mechanism for the infusion pump of FIG. 27;[0052]
• FIG. 29 shows an embodiment of a pump barrel locking mechanism of FIG. 27;[0053]
• FIG. 30 is an exploded view of the pump barrel locking mechanism of FIG. 27;[0054]
• FIG. 31 shows the relation of the drive screw to the plunger rod for the infusion pump of FIG. 27 when in a loading position;[0055]
• FIG. 32 shows the relation of the drive screw to the plunger rod for the infusion pump of FIG. 27 when in an engaged position;[0056]
• FIG. 33 shows a connection between the locking hub and the reservoir in accordance with one embodiment of the present invention;[0057]
• FIG. 34 shows another connection between the locking hub and the reservoir in accordance with one embodiment of the present invention;[0058]
• FIG. 35 shows an adapter for using a small diameter reservoir with the pump assembly in accordance with one embodiment of the present invention;[0059]
• FIG. 36 is an on-axis view of the adapter in FIG. 35 when the pump is in a loading position; and[0060]
• FIG. 37 is an on-axis view of the adapter in FIG. 35 when the pump is in an engaged position.[0061]
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
• FIG. 1 is an overall view of an infusion set[0062]10, in accordance with one embodiment of the invention, for delivery of a fluid to a patient. It may also be used to deliver fluid from a fluid delivery device to a porous medium. In the description, an infusion pump will serve as an example of a fluid delivery device and a human tissue will serve as an example of a porous medium. Fluid may be, for example, a drug, such as insulin. Like numbers in successive figures refer to the same or similar items.
• The infusion set[0063]10 includes a tubing set11. The tubing set11 includestubing13 that is attached at one end to ahub12. Thehub12 serves as an interface between thetubing13 and a pump assembly (not shown). Attached to the other end of the tubing set11 is aninfusion flap14 that interfaces with acannula assembly15.
• The[0064]cannula assembly15 includes acannula body17. Attached to thecannula body17 is acannula16, for subcutaneous insertion into the patient. Thecannula16 may be made of steel or alternatively, a soft and/or flexible material to help prevent patient discomfort, such as Teflon or other plastic. Thecannula16 may protrude from the bottom or side of thecannula body17 at various angles. For example, without limitation, thecannula16 may protrude from the front edge of thecannula body17 at a shallow angle of 15-30 degrees. As another example, thecannula16 may form a 90 degree angle with the bottom of thecannula body17. Further detail of thecannula assembly15 is provided in subsequent drawings including FIG. 2.
• Within the[0065]cannula body17 is a passageway adapted to receive the proximal or upstream end of thecannula16. The passageway includes at least one self-sealing septum that can be penetrated, for example, by an infusion or insertion needle.
• FIG. 2 is a further breakdown of parts in the infusion set shown in FIG. 1. The cannula assembly may be fabricated, in accordance with one embodiment of the invention, by inserting the[0066]cannula16 through a hole in acannula locking ring21. Thecannula locking ring21 is then attached to acore insert22 by a snap fit mechanism, ultrasonic welding, or other means known in the art. The proximal end of thecannula16 is flared, such that it is captured and held in place between thecore insert22 and the lockingring21. Both thecannula locking ring21 and core insert22 may be made of plastic or other suitable material.
• The[0067]core insert22 defines a passageway having a first end and a second end. The first end receives the proximal end of thecannula16, as described above. The second end of thecore insert22 acts asseptum housing23. A self-sealingseptum24 is inserted into the open end of theseptum housing23, which is then ultrasonically flared to capture theseptum24 inside thecore insert22. Thecore insert22 and lockingring21 are then overmolded to form asoft body17 for user comfort.
• The[0068]body17 of the cannula assembly is typically a compact and low profile component. When seen from the top, thecannula body17 may be, for example, circular, elliptical or triangular in shape and/or advantageously elongated for easy patient handling. All or aportion201 of thebody17 may be made clear or transparent to facilitate viewing of thecore insert22 and/or infusion site.
• The[0069]cannula16 may be inserted subcutaneously with the aid of aninsertion flap25. Theinsertion flap25 includes aninsertion needle26, typically made of steel, that assists thecannula16 in penetrating the skin. After inserting thecannula16, theinsertion flap25 is removed, and theinfusion flap14 is removably attached to thecannula assembly15 for delivery of fluid to the patient.
• In accordance with one embodiment of the invention, FIG. 3 shows a cross-sectional view of the[0070]cannula assembly15 with theinsertion flap25 attached. Theinsertion flap25 supports a proximal end of theinsertion needle26 which protrudes from theflap25 and terminates in a sharp distal end. When theinsertion flap25 is not in use and is removed from thecannula assembly15, the sharp end of theinsertion needle26 may be covered by a needle guard202 (shown in FIG. 2), which prevents accidental contact with theneedle26.
• The proximal end of the[0071]insertion needle26 is seated within a cylindrical shaped open ended (female)connector31 that slides onto and mates with themale septum housing23 of thecannula assembly15. The distal end of theinsertion needle26 is inserted through the self-sealingseptum24, through thecore insert22, and into thecannula16. When theinsertion flap25 andseptum housing23 are fully mated, the sharp tip of theinsertion needle26 may extend slightly beyond the distal end tip of thecannula16. The insertion flap may interface with an auto-insertion device (not shown) that can be used, for example, by a patient lacking the dexterity or strength to subcutaneously insert thecannula16 by him or her self. To interface with the auto-insertion device, theinsertion flap25 may include, for example, a flat top with a pair ofwings205 and206 and mountingholes203 and204 for attaching the auto-insertion device (see FIG. 2). When manually inserting thecannula16, the patient grasps the attachedinsertion flap25 and/orcannula body17 and pushes thecannula16, with theinsertion needle26 inserted, into the infusion site. The infusion site may be prepped prior to insertion of thecannula16 with a sterilizing fluid or by placement of a mounting patch onto the patient's skin, as known in the art. After thecannula16 has been inserted into the patient, theinsertion flap25 andneedle26 is withdrawn from thecannula assembly15. Thecannula assembly15 can then be secured to the patient by peeling a cover off an adhesive strip coupled to the bottom of thecannula body17, and pressing the adhesive281 against the patient's skin or mounting patch.
• Referring back to FIGS. 1 and 2, upon securing the[0072]cannula assembly15 to the patient, theinfusion flap14 is attached to thecannula assembly15 permitting fluid communication between the tubing set11 and thecannula16. Theinfusion flap14 may attach to the top or one of sides of thecannula assembly15. In accordance with one embodiment of the invention, FIG. 4 is a cross-sectional view of theinfusion flap14 mated (and locked) to thecannula assembly15. Theinfusion flap14 includes aninfusion needle42 attached to the inside of thetubing13, by, for example, a suitable adhesive. In various embodiments, the tubing may be microbore tubing. The proximal end of theinfusion needle42 is seated within a generally cylindrically shaped, open ended,female connector45 on theinfusion flap14 that slides onto and mates with themale septum housing23 of thecannula assembly15. The sharp, distal end of theinfusion needle42 typically does not extend beyond the open end of thefemale connector45, preventing inadvertent needle sticks and/or damage to the needle. When theinfusion flap14 is mated to thecannula assembly15, the infusion needle penetrates theseptum24, allowing fluid in thetubing13 to flow through thecannula16. The length of theinfusion needle42 is such that it does not protrude into, and damage thecannula16.
• So as to prevent inadvertent separation of the[0073]infusion flap14 and thecannula assembly15, a locking mechanism may be provided. The locking mechanism may include, without limitation, a lockingreceptacle43 on thefemale connector45 of theinfusion flap14 that engages a lockinglug44 on thecore insert22 of the cannula assembly. The lockinglug44 may be disposed on theseptum housing23, for example. FIG. 5 is a side view showing theinfusion flap14 in position for mating with thecannula assembly15. To slide themale septum housing23 into thefemale connector45, anopening slot51 of thereceptacle43 is aligned with the lockinglug44. When fully inserted, the base wall of thefemale connector45 may abut the distal end of themale septum housing23, and/or the distal end of theinfusion flap14 may make contact with the body of thecannula assembly15, such that the infusion needle pierces the septum contained within the septum housing.
• FIG. 6 is a detailed perspective view showing the[0074]infusion flap14 when mated to thecannula assembly15. To lock theinfusion flap14 onto thecannula assembly15, the locking lug44 (shown in FIG. 4) is engaged with thelug receptacle43 by rotating theinfusion flap14 clockwise. The locking lug44 (shown in FIG. 4) prevents theinfusion flap14 from disconnecting with thecannula assembly15 when a longitudinal force is applied, such as when thetubing13 is pulled on. In various embodiments, theinfusion flap14 may also include a snap fit mechanism to prevent theinfusion flap14 from inadvertently rotating open. The snap fit mechanism may include, without limitation, adetent62 that, when theinfusion flap14 is rotated clockwise, fits into anotch63 in thecannula body17.
• FIGS. 7 and 8 show a top view and side view of the tubing set[0075]11 locked to the cannula assembly. Theinfusion flap14 can be easily removed from thecannula assembly15 by lifting up on alift tab71 on theinfusion flap14 and rotating theinfusion flap14 counter-clockwise so as to align the slot51 (shown in FIG. 4) with the locking lug44 (shown in FIG. 4). Theinfusion flap14 is then pulled apart from thecannula assembly15 and the septum24 (shown in FIG. 4) self-seals.
• In accordance with another embodiment of the invention, FIG. 9 shows a cross-sectional view of an[0076]infusion flap97 attached to acannula assembly91 that includes afirst septum92 and asecond septum93 contained with aseptum housing94. Theseptum housing94 defines a passageway that is coupled to acannula95. Thefirst septum92 is advantageously located for penetration by aninsertion needle96, while the second septum is positioned for penetration by aninfusion needle99. To subcutaneously insert thecannula95, theinsertion needle96 is inserted through thefirst septum92 and into thecannula95. After cannula95 insertion, theinsertion needle96 is removed and thefirst septum92 self-seals to prevent fluid leakage. Thecannula assembly91 attaches to the user's body or mounting patch with an adhesive.
• As in previous embodiments,[0077]tubing98 is coupled at a first end to theinfusion flap97, and to a hub (not shown) that interfaces with a pump assembly at a second end. Aninfusion needle99 is attached to the inside of thetubing98 at the first end and is seated within a generally cylindrically shaped, open ended,female connector901 on theinfusion flap97. When theinfusion flap97 is mated to thecannula assembly91, theconnector901 slides onto and mates with themale septum housing94, such that theinfusion needle99 pierces thesecond septum93 allowing fluid in thetubing98 to flow to thecannula95.
• FIGS. 10 and 11 are a top view and a side view of the[0078]infusion flap97 in position for mating with thecannula assembly91. Theinsertion needle96 has been removed. To prevent inadvertent separation of theinfusion flap97 and thecannula assembly91, a locking mechanism for securing theinfusion flap97 to thecannula assembly91 may be provided. For example, thecannula assembly91 may include a lug receptacle1001 (see FIG. 10) that engages with a locking lug1101 (see FIG. 11) on theinfusion flap97. To lock theinfusion flap97 to thecannula assembly91, the locking lug is engaged with thelug receptacle1001 by rotating the infusion flap clockwise. Engagement in this fashion prevents disconnection of the tubing when pulled on. FIG. 12 shows theinfusion flap97 mated and locked onto thecannula assembly91.
• To remove the[0079]infusion flap97 from thecannula assembly91, one lifts up on alift tab1201 and rotates theinfusion flap97 counter-clockwise. Theinfusion flap97 is then pulled apart from thecannula assembly91 and the second septum93 (see FIG. 9) self-heals.
• In accordance with another embodiment of the invention, FIG. 13 is a cross-sectional view of an[0080]infusion flap1301 attached to acannula assembly1302, wherein thecannula assembly1302 includes asingle septum1303 located in arotatable septum housing1304. Asingle septum1303 androtatable septum housing1304 advantageously prevents leakage problems inherent in dual septum designs, while still permitting theseptum housing1304 to be positioned, for example, vertically for insertion of aninsertion needle1305, or horizontally after mating with theinfusion flap1301.
• The[0081]septum housing1304 is rotatably attached to the cannula assembly by, for example, a pivot or hinge mechanism. Attached to theseptum housing1304 and/orseptum1303 is a first end of aflexible tube1306, which is further attached at a second end to a proximal end of acannula1307 mounted within thecannula assembly1302. Theflexible tubing1306 may be attached to theseptum housing1304 and/orcannula assembly1302 using, without limitation, a suitable adhesive.
• [0082]Tubing1308 is coupled at a first end to theinfusion flap1301, and to a hub (not shown) that interfaces with a pump assembly at a second end. Aninfusion needle1309 is attached to the inside of thetubing1308 at the first end and is seated within an open ended,female connector1310 on theinfusion flap1301. Theconnector1310 andmale septum housing1304 may be of variable shape, such as, for example, a cylindrical, rectangular, or square shape. When theinfusion flap1301 is mated to thecannula assembly1302, theconnector1310 slides onto and mates with themale septum housing1304, such that theinfusion needle1309 pierces theseptum1303 allowing fluid in thetubing1308 to flow to thecannula1307. In various embodiments, theinfusion needle1305 is slightly larger than theinsertion needle1305, so as to seal the hole previously created by theinsertion needle1305.
• The[0083]infusion flap1301 is easily connected and disconnected to thecannula assembly1302. FIGS. 14 and 15 show a perspective view and a side view, respectively, of theinfusion flap1301 in position for mating with thecannula assembly1302. Theseptum housing1304 has been rotated such that it is perpendicular to the longitudinal axis of thecannula assembly1302, so as to allow for insertion of theinfusion flap1301. Theinsertion needle1305 has been removed. To prevent inadvertent separation of theinfusion flap1301 and thecannula assembly1302, a locking mechanism may be provided. The locking mechanism may include, for example, lockingtangs1401 and1402 on theinfusion flap1301 which engage withtang receptacles1403 and1404 located on thecannula assembly1302 when theinfusion flap1301 is pushed onto thecannula assembly1302. FIGS. 16 and 17 show a perspective view and a side view, respectively, of theinfusion flap1301 mated and latched onto thecannula assembly1302. At this point, theinfusion needle1309 penetrates theseptum1303 in the septum housing1304 (see FIG. 13). Upon being mated and latched onto thecannula assembly1302, theinfusion flap1301 andseptum housing1304 may be rotated90 degrees, such that the infusion flap lays flat against thecannula assembly1302, as shown in FIG. 18. A detent (not shown) may latch theinfusion flap1301 to thecannula assembly1302 with a snap action. Theflexible tube1306 bends as theseptum housing1304 rotates, providing a leak tight fluid path between thetubing1308 and thecannula1307.
• To remove the[0084]infusion flap1301 from thecannula assembly1302, one lifts up on, and rotates theinfusion flap1301 90 degrees so that theseptum housing1304 is once again perpendicular to the longitudinal axis of thecannula assembly1302. Theinfusion flap1301 is then disengaged by pinching thelocking tangs1401 and1402 towards each other, and pulling theinfusion flap1301 away from thecannula assembly1302.
• In accordance with another embodiment of the invention, FIG. 19 is a cross-sectional view of an[0085]infusion flap1901 attached to acannula assembly1902 that, similar to the above described embodiment, includes asingle septum1903 located in arotatable septum housing1904, but which has an alternative locking mechanism. FIG. 19 shows theinfusion flap1901 and thecannula assembly1902 in a mated position, just prior to being latched. The insertion needle has been removed1905.
• The open ended female connector[0086]1910 (see FIG. 20) on theinfusion flap1901, which seats theinfusion needle1909, is generally cylindrical shaped, such that the connector can be slid onto and mated with themale septum housing1904. FIGS. 20, 21, and22 show a perspective view, a top view and a side view, respectively, of theinfusion flap1901 in position for mating with thecannula assembly1902. Themale septum housing1904 includes alocking lug2001 which mates with alug receptacle2002 on theconnector1910. The user alignsrecepticle slot2003 on thefemale connector1910 with the lockinglug2001, such that thefemale connector1910 can be slid onto, and mated with, themale septum housing1904. FIGS. 23 and 24 show a perspective view and a side view, respectively, of theinfusion flap1901 mated with thecannula assembly1902. At this point, theinfusion needle1909 pierces the septum1903 (see FIG. 19).
• The[0087]locking lug2001 is then engaged with thelug receptacle2002 by rotating theinfusion flap25 counterclockwise (or clockwise depending on the location of the lug recepticle), as shown in FIG. 25. After engagement, theinfusion flap1901 andseptum housing1904 can be rotated 90 degrees, such that theinfusion flap1901 lays flat against thecannula assembly1902, as shown in FIG. 26. A detent (not shown) may latch theinfusion flap1901 to thecannula assembly1902 with a snap action. Theflexible tube1906 bends as theseptum housing1904 rotates, providing a leak tight fluid path between thetubing1908 and thecannula1907.
• To remove the[0088]infusion flap1901 from thecannula assembly1902, one lifts up on alift tab2601 on theinfusion flap1901 and rotates theinfusion flap1901 90 degrees so that theseptum housing1904 is perpendicular to the longitudinal axis of thecannula assembly1902. Theinfusion flap1901 is then disengaged by rotating the infusion flap 90 degrees clockwise, and pulling theinfusion flap1901 away from thecannula assembly1902.
• Referring back to FIG. 1, the[0089]tubing13 attaches at one end to ahub12 for interfacing and receiving a fluid from a fluid delivery device (not shown). The fluid may be a drug, such as insulin. The fluid delivery device may be, without limitation, an infusion pump assembly.
• The[0090]hub12 may be of various shape. For example, thehub12 may be asymmetric, circular, or elliptical in shape. Thehub12 may be made of plastic, metal, or other suitable material. Thehub12 may include a receptacle for receiving thetubing13. Thetubing13 may be permanently attached to thehub12 using a suitable adhesive. In other embodiments, thetubing13 may be removably attached to thehub12 using, for example, a luer connection.
• The[0091]hub12 may include a controller which allows the fluid delivery device to transition from a first configuration to a second configuration. The first and second configuration may be, for example, a pump reservoir load position and a pump operate position, respectively. While the controller is implemented as a flange in following FIGS.27-37, it is to be understood that the controller can be implemented in a wide variety of forms, such as, but not limited to, mechanical, electrical, magnetic, or optical forms. For example, without limitation, thehub12 may include a flange or other mechanical protrusion that interfaces with the pump assembly, or thehub12 may generate a magnetic field or optical signal that is sensed by a Hull Effect sensor or optical sensor positioned on the pump assembly, respectively. In still another embodiment, a wire in thehub12 may complete a circuit in the pump assembly.
• FIG. 27 is an overall view of a hub and infusion pump according to one embodiment of the present invention. A[0092]pump assembly2710 contains the components needed to cause areservoir assembly2715 to deliver medication to a user. Thereservoir assembly2715 may contain enough medication, such as insulin, for several days for a typical user. Ahub2725 has a coupling to the reservoir assembly, thehub2725 permanently affixed to atubing set2720 for delivery of the fluid to a patient.
• FIG. 28 shows an exploded view of the drive mechanism of the infusion pump. The[0093]reservoir assembly2715 comprises areservoir2830,plunger2835 andplunger rod2840. Thereservoir2830 contains the medication for delivery to the user and is of variable interior volume. The interior volume is the liquid capacity of the reservoir. Theplunger2835, inserted into the bottom of the reservoir, causes the volume of the reservoir to change as the plunger is displaced along the longitudinal axis of the reservoir. Theplunger rod2840 is connected to the plunger with the rod's longitudinal axis displaced from and parallel to the longitudinal axis of the reservoir. Theplunger rod2840 is threaded for at least a portion of the rod's length. Acylindrical pump barrel2845 receives thereservoir assembly2715. The pump barrel constrains the plunger rod, orienting the rod along the longitudinal axis of the barrel. Thepump barrel2845 is contained in the pump assembly and may contain a locking mechanism, such as a locking tab, to prevent rotation of the pump barrel with respect to the assembly. Agear box2855 in thepump assembly2715 includes adrive screw2850 along with motor and gears to turn the drive screw. Thedrive screw2850 is threaded and the screw's longitudinal axis is aligned parallel to and displaced from the longitudinal axis of the pump barrel. Thehub2725 has a coupling to the top of the reservoir.
• FIG. 29 shows a pump barrel locking mechanism for an embodiment of the invention. The[0094]pump barrel2845 includes aclearance hole3072 in one end (shown in FIG. 31) that guides theplunger rod2840 during insertion of thereservoir assembly2715 into thebarrel2845. To ensure that thedrive screw2850 does not interfere with theplunger rod2840 during insertion of the reservoir assembly, thepump barrel2845 maintains a fixed position relative to thepump assembly2710. The position of the pump barrel relative to the pump assembly may be maintained, for example, by alocking tab3060 included in the pump barrel that engages apump barrel stop3065 in thepump assembly10. FIG. 30 is a detailed view of the pump barrel showing thelocking tab3060 and pump barrel stop3066. Referring back to FIG. 29, thehub2725 includes aflange2970 which dislodges thelocking tab3060 from thebarrel stop3065 when thehub2725 turns, allowing thehub2725 to rotate thepump barrel2845.
• FIGS. 31 and 32 are views along the longitudinal axis of the[0095]pump barrel2845 showing the relation of thedrive screw2850 to theplunger rod2840 in a loading position and in an engaged position, respectively. Thereservoir assembly2715 is positioned for loading so that theplunger rod2840 does not contact thedrive screw2850, as shown in FIG. 31. With thepump barrel2845 positioned appropriately with respect to thepump assembly2710, theplunger rod2840 clearance from thedrive screw2850 is determined by the placement of theclearance hole3072 in thepump barrel2845 base, whichhole3072 receives and guides theplunger rod2840. Theclearance hole3072 may be tapered to ease insertion of therod2840. Thedrive screw2850 fits in theclearance hole3072 in thepump barrel2845. Once thereservoir assembly2715 is inserted into thepump assembly2710, thebarrel2845 is rotated by thelocking hub2725, causing theplunger rod2840 to turn and to engage thedrive screw2850, as shown in FIG. 32. This embodiment advantageously simplifies reservoir loading.
• In a specific embodiment of the invention, the plunger rod threads and the drive screw threads are buttress threads. This embodiment advantageously addresses eliminating reaction forces on the plunger rod normal to the direction of the rod's longitudinal axis. Such reaction forces may cause the rod to deflect and skip a thread on the drive screw, resulting in under delivery of medication to the user. Buttress threads eliminate the normal component of the reaction force.[0096]
• In an embodiment of the present invention, the[0097]locking hub2725 may be connected to thereservoir2830 by a tapered luer connection, as shown in FIG. 33. The reservoir has amale luer taper3375 integrally molded into the reservoir's top. Surrounding the male luer is anannulus3378 with an internal female thread. Similarly, thehub2725 includes the mating female luer and threaded male connection.
• In another embodiment of the invention, a needle connection is provided between[0098]reservoir2830 andhub2725. As shown in FIG. 34, the reservoir includes arubber septum3480 that is attached to the reservoir with a crimped metal collar. Aneedle3485, integral to the hub, pierces the septum and fluid can then flow from the reservoir to the tubing set.
• In a further embodiment of the invention, as shown in FIG. 35, an[0099]adapter3595 is provided to permit areservoir3590 whose diameter is substantially smaller than the diameter of thepump barrel2845 to be used with thepump assembly2710. Theadapter3590 may be a separate component or may be integrated into thelocking hub2725. Theadapter3595 aligns and offsets the reservoir's3590 axis parallel to the longitudinal axis of the pump barrel so that theplunger rod2840, when rotated, mates with the drive screw. FIGS. 36 and 37 shows an on-axis view of thesmall diameter reservoir3590 when placed in theadapter3595 in a loading position and in an engaged position, respectively. As will be apparent, the offset provided by the adapter allows the plunger rod3840, when mated with the plunger3835 andreservoir3590, to engage the drive screw3850 in the same fashion as for the embodiment shown in FIGS. 31 and 32.
• Having described various illustrative embodiments of the present invention, some of its advantages and optional features, it will be apparent that such embodiments are presented by way of example only and not by way of limitation. Those skilled in the art could readily devise alterations and improvements on these embodiments, as well as additional embodiments, without departing from the spirit and scope of the invention. All such modifications are within the scope of the invention as claimed.[0100]

Claims (43)

What is claimed is:

1. A medical device for delivery of a fluid to a patient from a line terminating in a tubing needle, the medical device comprising:

a cannula assembly for coupling the fluid into a cannula for insertion into the patient, the cannula assembly having a first locking element disposed in a fixed position with respect to the cannula; and

an infusion flap for coupling the line to the cannula assembly, the infusion flap comprising:

a second locking element for engaging the first locking element of the cannula assembly; and

a lift tab for disconnecting the infusion flap from the cannula assembly, wherein coupling of the first and second locking elements requires initial mating of the infusion flap and cannula assembly followed by locking through rotation of the infusion flap with respect to the cannula assembly.

2. The medical device according toclaim 1, where the first locking element is a locking lug and the second locking element is a lug receptacle.

3. The medical device according toclaim 1, wherein the first locking element is a lug receptacle and the second locking element is a locking lug.

4. The medical device according toclaim 1, wherein the cannula assembly includes a septum housing defining a core coupled to the cannula, the septum housing including a first septum positioned within the core at a first position, such that when the infusion flap and the cannula assembly are locked, the tubing needle penetrates the first septum so as to permit fluid communication between the line and the cannula.

5. The medical device according toclaim 4, wherein the septum housing includes a second septum positioned within the core at a second position, such that an insertion needle can be introduced through the second septum into the cannula.

6. The medical device according toclaim 1, wherein the cannula assembly includes a soft overmolded body.

7. A medical device according toclaim 1, the cannula assembly further including:

a flexible tube in fluid communication with the cannula; and

a septum in fluid communication with flexible tube, wherein, when the flexible tube is in a first position, an insertion needle can be introduced through the septum into the cannula, and when the flexible tube is in a second position, a tubing needle inserted through the septum permits fluid communication between the line and the cannula.

8. The device according toclaim 1, further comprising an insertion flap, the insertion flap including an insertion needle for inserting into the passagway through the septum, the insertion flap when inserted further extending through the cannula and terminating with a sharp distal end disposed slightly beyond a distal end of the cannula.

9. The device according toclaim 1, wherein the insertion flap has an interface for coupling to an auto-insertion device.

10. A medical device for delivery of a fluid to a patient from a line terminating in a tubing needle, the medical device comprising:

a cannula for insertion into the patient;

a flexible tube in fluid communication with the cannula; and

a septum in fluid communication with the flexible tube, wherein when the flexible tube is in a first position, an insertion needle can be introduced through the septum into the cannula, and when the flexible tube is in a second position, a tubing needle inserted through the septum permits fluid communication between the line and the cannula.

11. The device according toclaim 10, further comprising:

an infusion flap that includes the tubing needle; and

a cannula assembly that includes the cannula;

wherein when the infusion flap and cannula assembly are mated, the tubing needle passes through the septum permitting fluid communication between the line and the cannula.

12. The device according toclaim 11, further comprising a locking mechanism for securing the infusion flap to the cannula assembly.

13. The device according toclaim 12, wherein the locking mechanism includes a locking tang on the infusion flap, the locking tang inserted into a tang receptacle on the cannula assembly.

14. The medical device according toclaim 12, wherein the septum is disposed in a septum housing, and the locking mechanism includes a first locking element disposed on the septum housing and a second locking element disposed on the infusion flap, wherein coupling of the first and second locking elements requires initial mating of the infusion flap and cannula assembly followed by locking through rotation of the infusion flap with respect to the cannula assembly.

15. The medical device according toclaim 14, where the first locking element is a locking lug and the second locking element is a lug receptacle.

16. The medical device according toclaim 14, wherein the first locking element is a lug receptacle and the second locking element is a locking lug.

17. The device according toclaim 14, wherein the septum housing can be rotated to a mating position that allows the infusion flap and the septum housing to be mated together and the infusion flap rotated with respect to the cannula assembly to lock the infusion flap onto the septum housing, and

wherein the septum housing can then be rotated to a stable position that prevents rotation of the infusion flap.

18. The device according toclaim 10, further comprising an insertion flap, the insertion flap including an insertion needle for inserting into the passagway through the septum, the insertion flap when inserted further extending through the cannula and terminating with a sharp distal end disposed slightly beyond a distal end of the cannula.

19. The device according toclaim 18, wherein the insertion flap has an interface for coupling to an auto-insertion device.

20. A method for delivering a fluid to a patient from a line terminating in a tubing needle, the method comprising,

inserting an insertion needle through a septum and a cannula, the septum and the cannula having a relative orientation;

inserting the cannula into tissue of a patient;

withdrawing the insertion needle from the cannula and the septum;

inserting the tubing needle through the septum;

varying the relative orientation between the septum and the cannula; and

delivering a fluid through the line and the cannula.

21. A tubing set for coupling a fluid delivery device into fluid communication with a cannula assembly, the fluid delivery device having a first configuration and a second configuration, the tubing set comprising:

a length of tubing having a first end and a second end;

a hub coupled to the first end for connecting to the fluid delivery device, the hub including a controller for allowing fluid delivery device to transition from the first configuration to the second configuration; and

an infusion flap coupled to the second end for connecting to the cannula assembly.

22. The tubing set according toclaim 21, wherein the first configuration of the source is a reservoir load position and the second configuration is an operate position.

23. The tubing set according toclaim 21, wherein the controller is capable of allowing the fluid delivery device to transition from the second configuration to the first configuration.

24. The tubing set according toclaim 21, wherein the controller includes a flange that interfaces with the fluid delivery device.

25. The tubing set according toclaim 21, wherein the controller includes generating one of an optical signal and magnetic field.

26. The tubing set according toclaim 21, wherein the controller includes an electronic circuit to the fluid delivery device.

27. The tubing set according toclaim 21, wherein the hub includes a luer connector for mating with the fluid delivery device.

28. The tubing set according toclaim 21, wherein the fluid delivery device is an infusion pump having a reservoir with variable volume and a drive assembly, the drive assembly including a barrel having a clearance hole in a barrel end, the barrel characterized by a longitudinal barrel axis of rotation, the drive assembly further including a plunger rod inserted through the clearance hole, and a rotating drive screw with external threads that removably engages with threads on the plunger rod by rotating the barrel about the barrel axis, the external threads engaged with the threads on the plunger rod when in the first configuration and the external threads disengaged with the threads on the plunger rod when in the second second configuration, and

wherein the controller is capable of allowing the barrel to rotate so as to bring the rod threads in and out of mechanical engagement with the drive screw threads.

29. The tubing set according toclaim 28, wherein the controller includes a flange for dislodging a locking tab on the barrel, allowing the barrel to rotate.

30. The tubing set according toclaim 20, wherein the cannula assembly has a first locking element disposed in a fixed position with respect to the cannula; and

the infusion flap includes:

a tubing needle;

a second locking element for engaging the first locking element of the cannula assembly; and

a lift tab for disconnecting the infusion flap from the cannula assembly, wherein coupling of the first and second locking elements requires initial mating of the infusion flap and cannula assembly followed by locking through rotation of the infusion flap with respect to the cannula assembly.

31. The tubing set according toclaim 30, wherein the tubing needle penetrates a septum in the cannula assembly when the infusion flap is locked to the cannula assembly, permitting fluid communication between the tubing set and a cannula protruding from the cannula assembly.

32. A conduit for coupling to a fluid delivery device, the fluid delivery device having a first configuration and a second configuration, the conduit comprising:

a length of tubing having a first end; and

a hub coupled to the first end for connecting to the fluid delivery device, the hub including a controller for allowing the fluid delivery device to transition from the first configuration to the second configuration.

33. The conduit according toclaim 32, wherein the first configuration is a reservoir load position and the second configuration is an operate position.

34. The conduit according toclaim 32, wherein the hub includes a luer connector for mating with the fluid delivery device.

35. The conduit according toclaim 32, wherein the controller includes a flange that interfaces with the fluid delivery device.

36. The conduit according toclaim 32, wherein the controller includes generating one of an optical signal and magnetic field.

37. The conduit according to32, wherein the controller includes completing an electronic circuit in the fluid delivery device.

38. A method of providing flow of a fluid from a fluid delivery device to a porous medium, the method comprising:

coupling a hub to the fluid delivery device, the hub permanently affixed to a tube set;

controlling a configuration of the fluid delivery device via the hub; and

coupling the tube set to the porous medium so as to allow fluid to flow from the fluid delivery device to the porous medium.

39. The method according toclaim 38, wherein controlling the configuration of the fluid delivery device includes allowing the pump to move from a first configuration to a second configuration.

40. The method according toclaim 39, wherein the first configuration of the fluid delivery device is a load position and the second configuration is an operate position.

41. The method according toclaim 38, wherein controlling the configuration of the fluid delivery device includes moving a flange on the hub.

42. The method according toclaim 38, wherein controlling the configuration of the fluid delivery device includes generating one of a magnetic field and an optical signal.

43. The method according toclaim 38, wherein the fluid delivery device is an infusion pump.

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