Button safety cap for catheter insertion device

A button safety cap for a patch pump or other fluid infusion device prevents accidental activation of an activation button of a catheter insertion device. The button safety cap includes a stabilizing surface adapted to stabilize the patch pump when the patch pump is oriented for filling a reservoir port.

FIELD OF THE INVENTION

The present invention is directed to a catheter insertion device and to a fluid infusion device including the catheter insertion device. More particularly, the present invention is directed to a button safety cap for preventing accidental deployment of the catheter, and to provide a stable configuration for filling a reservoir of the fluid infusion device.

BACKGROUND OF THE INVENTION

Diabetes is a group of diseases characterized by high levels of blood glucose resulting from the inability of diabetic patients to maintain proper levels of insulin production when required. Persons with diabetes may require some form of daily insulin therapy to maintain control of their glucose levels. Diabetes can be dangerous to the affected patient if it is not treated, and it can lead to serious health complications and premature death. However, such complications can be minimized by utilizing one or more treatment options to help control the diabetes and reduce the risk of complications.

The treatment options for diabetic patients include specialized diets, oral medications and/or insulin therapy. The main goal of diabetes treatment is to control the diabetic patient's blood glucose or sugar level. However, maintaining proper diabetes management may be complicated because it has to be balanced with the activities of the diabetic patient.

For the treatment of type 1 diabetes, there are two principal methods of daily insulin therapy. In the first method, diabetic patients use syringes or insulin pens to self-inject insulin when needed. This method requires the needle stick for each injection, and the diabetic patient may require three to four injections daily. The syringes and insulin pens that are used to inject insulin are relatively simple to use and cost effective.

Another effective method for insulin therapy and managing diabetes is infusion therapy or infusion pump therapy in which an insulin pump is used. The insulin pump can provide continuous infusion of insulin to a diabetic patient at varying rates in order to more closely match the functions and behavior of a properly operating pancreas of a non-diabetic person that produces the required insulin, and the insulin pump can help the diabetic patient maintain his/her blood glucose level within target ranges based on the diabetic patient's individual needs.

Infusion pump therapy requires an infusion cannula, typically in the form of an infusion needle or a flexible catheter, that pierces the diabetic patient's skin and through which, infusion of insulin takes place. Infusion pump therapy offers the advantages of continuous infusion of insulin, precision dosing, and programmable delivery schedules.

In infusion therapy, insulin doses are typically administered at a basal rate and in a bolus dose. When insulin is administered at a basal rate, insulin is delivered continuously over 24 hours in order to maintain the diabetic patient's blood glucose levels in a consistent range between meals and rest, typically at nighttime. Insulin pumps may also be capable of programming the basal rate of insulin to vary according to the different times of the day and night. In contrast, a bolus dose is typically administered when a diabetic patient consumes a meal, and generally provides a single additional insulin injection to balance the consumed carbohydrates. Insulin pumps may be configured to enable the diabetic patient to program the volume of the bolus dose in accordance with the size or type of the meal that is consumed by the diabetic patient. In addition, insulin pumps may also be configured to enable the diabetic patient to infuse a correctional or supplemental bolus dose of insulin to compensate for a low blood glucose level at the time when the diabetic patient is calculating the bolus dose for a particular meal that is to be consumed.

Insulin pumps advantageously deliver insulin over time rather than in single injections, typically resulting in less variation within the blood glucose range that is recommended. In addition, insulin pumps may reduce the number of needle sticks which the diabetic patient must endure, and improve diabetes management to enhance the diabetic patient's quality of life.

Typically, regardless of whether a diabetic patient uses multiple daily injections (MDIs) or a pump, the diabetic patient takes fasting blood glucose medication (FBGM) upon awakening from sleep, and also tests for glucose in the blood during or after each meal to determine whether a correction dose is required. In addition, the diabetic patient may test for glucose in the blood prior to sleeping to determine whether a correction dose is required, for instance, after eating a snack before sleeping.

To facilitate infusion therapy, there are generally two types of insulin pumps, namely, conventional pumps and patch pumps. Conventional pumps require the use of a disposable component, typically referred to as an infusion set, tubing set or pump set, which conveys the insulin from a reservoir within the pump into the skin of the user. The infusion set consists of a pump connector, a length of tubing, and a hub or base from which a cannula, in the form of a hollow metal infusion needle or flexible plastic catheter extends. The base typically has an adhesive that retains the base on the skin surface during use. The cannula can be inserted onto the skin manually or with the aid of a manual or automatic insertion device. The insertion device may be a separate unit required by the user.

Another type of insulin pump is a patch pump. Unlike a conventional infusion pump and infusion set combination, a patch pump is an integrated device that combines most or all of the fluidic components, including the fluid reservoir, pumping mechanism and mechanism for automatically inserting the cannula, in a single housing which is adhesively attached to an infusion site on the patient's skin, and does not require the use of a separate infusion or tubing set. A patch pump containing insulin adheres to the skin and delivers the insulin over a period of time via an integrated subcutaneous cannula. Some patch pumps may wirelessly communicate with a separate controller device (as in one device sold by Insulet Corporation under the brand name OmniPod®), while others are completely self-contained. Such devices are replaced on a frequent basis, such as every three days, when the insulin reservoir is exhausted or complications may otherwise occur, such as restriction in the cannula or the infusion site.

As patch pumps are designed to be a self-contained unit that is worn by the diabetic patient, it is preferable to be as small as possible so that it does not interfere with the activities of the user. Thus, in order to minimize discomfort to the user, it would be preferable to minimize the overall thickness of the patch pump. However, in order to minimize the thickness of the patch pump, its constituent parts should be reduced as much as possible. One such part is the insertion mechanism for automatically inserting the cannula into the user's skin.

In some patch pumps, there is an activation button that triggers deployment of the catheter. Such patch pumps also include a fill port for filling a reservoir of the patch pump with insulin, or the like. One problem with button-based catheter insertion mechanisms is accidental pressing of the activation button. In particular, if the fill port is on the bottom of the pump or other medication delivery device, a user may turn the device upside down and rest it on a surface while they inject fluid into the fill port. This action risks the user accidentally causing the button to be pressed. Furthermore, if the deployment button is on the top of the device, and the user turns the device over to fill the reservoir, the pre-activation button may present an unstable configuration for resting the device on a surface while filling the reservoir.

Accordingly, a need exists for an improved insertion mechanism that includes a button safety feature or device to prevent accidental activation of the catheter insertion device, and to provide a stable configuration for filling the reservoir.

SUMMARY OF THE INVENTION

The present invention is directed to a button safety cap for a catheter insertion device. The button safety cap comprises a pull member, at least one stabilizing arm adapted to prevent rotation and/or translation of the button safety cap relative to the activation button and/or a patch pump or other medication delivery device upon which the button safety cap is assembled, and a flexible snap feature adapted to engage an activation button of the patch pump. The snap feature retains the button safety cap on the patch pump until a predetermined removal force is applied to the button safety cap.

These and other aspects of the invention will become apparent from the following detailed description of the invention which, taken in conjunction with the annexed drawings, show various embodiments of the invention.

Throughout the drawings it will be understood that like reference numbers refer to like features and structures.

FIG. 1is a perspective view of an illustrative embodiment of a patch pump1according to an illustrative embodiment of the invention. The patch pump1is illustrated with a see-through cover for clarity and illustrates various components that are assembled to form the patch pump1.FIG. 2is an exploded view of the various components of the patch pump ofFIG. 1, illustrated with a solid cover2. The various components of the patch pump1may include: a reservoir4for storing insulin; a pump3for pumping insulin out of the reservoir4; a power source5in the form of one or more batteries; an insertion mechanism7for inserting an inserter needle with a catheter into the user's skin; control electronics8in the form of a circuit board with optional communications capabilities to outside devices such as a remote controller and computer, including a smart phone; a dose button6on the cover2for actuating an insulin dose, including a bolus dose; and a base9to which various components above may be attached via fasteners91. The patch pump1also includes various fluid connector lines that transfer insulin pumped out of the reservoir4to the infusion site.

It should be understood that inserter mechanisms come in various configurations. In some embodiments, the inserter mechanism inserts a soft catheter into the skin. In these embodiments, typically the soft catheter is supported on a rigid insertion needle. The insertion needle is inserted into the skin along with the soft catheter, and then retracted from the skin, leaving the soft catheter in the skin. In other embodiments, a soft catheter is not provided, and the insertion needle remains in the skin and forms a portion of the insulin flow path to deliver insulin until the infusion is finished. Insertion needles are typically hollow, and need to be hollow if they form part of the insulin flow path. However, insertion needles that support a soft catheter and then retract may be solid or hollow. If the insertion needle deploys a soft catheter, and retracts but remains part of the insulin flow path, then the insertion needle should be hollow. However, if the insertion needle deploys a soft catheter and then retracts but does not form part of the insulin flow path, then the insertion needle may be solid or hollow. In either case, the insertion needle is preferably rigid enough to reliably penetrate the skin, but otherwise may be made flexible enough to provide comfort to the user.

FIG. 3is a perspective view of an alternative design for a patch pump1A having a flexible reservoir4A, and illustrated without a cover. Such arrangement may further reduce the external dimensions of the patch pump1A, with the flexible reservoir4A filling voids within the patch pump1A. The patch pump1A is illustrated with a conventional cannula insertion device7A that inserts the cannula, typically at an acute angle, less than 90 degrees, at the surface of the user's skin. The patch pump1A further comprises: a power source5A in the form of batteries; a metering sub-system41that monitors the volume of insulin and includes a low volume detecting ability; control electronics8A for controlling the components of the device; and a reservoir fill port43for receiving a refill syringe45to fill the reservoir4A.

FIG. 4is a patch-pump fluidic architecture and metering sub-system diagram of the patch pump1A ofFIG. 3. The power storage sub-system for the patch pump1A includes batteries5A. The control electronics8A of the patch pump1A may include a microcontroller81, sensing electronics82, pump and valve controller83, sensing electronics85, and deployment electronics87that control the actuation of the cannula insertion mechanism. The patch pump1A includes a fluidics sub-system that may include a reservoir4A, volume sensor47for the reservoir4A, a reservoir fill port43for receiving a refill syringe45to refill the reservoir4A. The fluidics sub-system may include a metering system comprising a pump and valve actuator411and an integrated pump and valve mechanism413. The fluidics sub-system may further include an occlusion sensor, a deploy actuator, as well as the cannula47for insertion into an infusion site on the user's skin. The architecture for the patch pumps ofFIGS. 1 and 2is the same or similar to that which is illustrated inFIG. 4.

Embodiments of the present invention include a button safety cap to prevent accidental activation of a catheter insertion mechanism of a patch pump and to stabilize the device while the user is filling a reservoir of the patch pump. The embodiment described herein is particularly adapted to work with the insertion mechanism described in further detail in PCT Patent Application No. PCT/US15/27367, but it should be readily appreciated by those of ordinary skill in the art that with modifications to the particular configuration of the button safety cap, embodiments of the present invention can be adapted to work with any insertion mechanism having a button. Embodiments of the present invention can work with patch pumps having cannula insertion mechanisms that use a rigid needle to drive a soft cannula into the skin of a user, and then retract the rigid needle leaving the soft cannula in the skin, and may also work with insertion mechanisms that utilize a rigid indwelling needle.

Accidental activation can cause needle stick injury, so it is desirable to provide a button safety device that prevents such injuries. If the insertion mechanism were to be accidentally activated before being placed on the skin, the patch pump would no longer be usable if the catheter insertion mechanism cannot be reset. If the reservoir was filled before the accidental activation, the insulin would also be wasted. Without a button safety, accidental activation could occur by the user accidentally pushing the button while handling the device before it is placed on the skin. The insertion mechanism described in PCT Patent Application No. PCT/US15/27367 has a feature that prevents the needle from being exposed from the bottom of the medication delivery device when a small amount of force is applied but, if a force higher than that threshold is accidentally applied, the user could be injured by the introducer needle. With reference toFIGS. 14 and 15, if the insertion mechanism activation button514was pushed all the way down before the device502was adhered to the body, the catheter534would lock in the distal position as shown inFIG. 15, and the introducer needle would retract thus rendering the insertion mechanism unusable. If the button514was pushed with enough force to surpass the minimum threshold force but not pushed the full stroke length, the introducer needle would be exposed and possibly be injuring the user but the needle and catheter would retract back into the device. In this scenario, the insertion mechanism would be reset and could be used to insert the catheter into the skin.

The insertion mechanism activation button514can be accidentally activated during the reservoir fill step. With reference toFIGS. 12 and 13, the reservoir fill port is typically on the opposite side of the device502as the insertion mechanism activation button514. The user inserts a syringe needle through the fill port septum566and injects the contents of the syringe to fill a reservoir in the device502. If the device was placed with the fill port facing up on a surface, then without a button safety cap the device would rest on the insertion mechanism activation button514. If the device502is pushed downwards with sufficient force, the insertion mechanism can activate and be deployed as illustrated inFIG. 15. Pushing the syringe plunger to fill the reservoir could cause this to occur.

FIGS. 5, 6, 7, 8, 9 and 16illustrate a button safety cap500according to an illustrative embodiment of the invention.FIGS. 10, 11 and 12illustrate the button safety500installed onto a patch pump502. Patch pump502is preferably manufactured with the button safety cap500assembled onto the patch pump502. When installed on the patch pump502, the button safety cap500covers the pre-activation insertion mechanism activation button514to prevent accidental activation. The button safety cap500is preferably, but not necessarily, a single molded part constructed of a rigid but flexible material such as plastic.

As illustrated, the button safety cap500includes a pull member504that the user may pull to remove the button safety cap500from the patch pump when the user is ready to activate the catheter insertion mechanism (e.g., via a button514). Button safety cap500also preferably includes a contoured surface506to stabilize the button safety cap on the patch pump502housing. With reference toFIGS. 6, 9 and 10, the surface506of the button safety cap500is contoured along a side of the pump502and therefore vertical axis of the pump that is parallel to longitudinal axis of button514for increased stabilization of the button safety cap500relative to the pump. The button safety cap500can also include stabilizing arms508and510disposed, respectively, along transverse and longitudinal axes of the pump502for increased stabilization of the button safety cap500relative to the pump502.

The height dimension of the button safety cap500(e.g., combined dimension of the arm508that extends along the vertical axis of the pump and the thickness of the pull504) is configured to accommodate the insertion mechanism at its full pre-deployment position as illustrated inFIG. 14. The insertion mechanism can be damaged if its activation button514is torqued with enough force. Contoured surface506and stabilizing arms508and510constrain the button safety cap500on the patch pump502to prevent rotation or translation in directions that could damage the device or torque the insertion mechanism activation button514.

FIGS. 8, 9 and 11, the pull member504has a cutout518with a snap feature512. The snap feature512is configured to extend partially across the cutout518to provide some flexibility to the snap feature512. As shown inFIG. 11, the snap feature512is also configured to extend along the parallel and respective vertical axis of the pump502and longitudinal axis of its insertion mechanism activation button514. The snap feature512has an angled surface that engages a surface or edge530of the button514to provide some tension to retain the button safety500cap on the button514but to release the cap500from the button514upon the application of a designated amount of force on the pull member504corresponding to when the user wishes to remove the cap500from the button514and depress the button514to deploy the insertion mechanism.

FIG. 9is a cross-sectional view of the button safety cap500, showing the snap feature512.FIG. 11is a cross-section of the button safety cap500assembled onto the patch pump502. As shown inFIG. 11, snap feature512locks the button safety cap500onto insertion mechanism activation button514until sufficient force is used to overcome the predetermined deformation force required to disengage snap feature512from the surface or edge30of the insertion mechanism activation button514. In this manner, the button safety500is held onto the patch pump502until intentionally removed by the user. The snap feature512is preferably designed to disengage from the activation button514when excessive torque is applied around the activation button514primary axis in order to prevent damage to the insertion mechanism.

The shape of the insertion mechanism activation button514can be configured with opposing flat sides528as illustrated inFIGS. 14, 15 and 16to facilitate assembly and prevent rotation of the insertion mechanism activation button514in an aperture532in the device502housing through which insertion mechanism activation button514deploys. In addition, the button safety cap500comprises a cavity546with a corresponding shape to match the circumference of the button514such that the button safety cap500and button514can be assembled without rotational motion that could damage the insertion mechanism and make assembly more difficult.

With reference toFIGS. 8 and 16, the underside of the button safety cap500has a cavity546that is dimensioned to receive the insertion mechanism activation button514when in its undeployed position (e.g., seeFIG. 14). As stated above, the insertion mechanism activation button514can have opposing flat surfaces or sides528. One of the flat surfaces or sides528comprises the surface or edge530that engages the snap feature512to retain the button safety cap500on the button514until the cap500is intentionally removed from the button514by a user. The button safety cap500has a corresponding mating flat surface548that abuts the other one of the flat surfaces or edges528of the button514to constrain the button in the assembled state.

Turning back toFIG. 6, the button safety500pull member504is preferably elongated and includes an edge516that makes contact with a flat surface when the patch pump is turned over by a user to fill the reservoir port located on the bottom of the patch pump housing. Edge516stabilizes the patch pump while resting upside-down on a surface for reservoir filling. In this manner, reservoir filling is made easier for the user, and at the same time the button safety500prevents accidental activation of the activation button514while the user is potentially pressing down on the patch pump while it is turned over.

Further, the pull member504can be dimensioned and shaped to optimize ergonomics of the user's hand and particularly the action of the thumb and fingers on the user's hand to make removal of the button safety cap500convenient and with an efficient user motion. As illustrated, the pull member504has ends520and522. The width of the contour surface506(i.e., the dimension of contour surface506along the transverse axis of the pump502) and the spacing of the contour surface506along the pull member504relative to its ends520and522can accommodate, for example, the thumb and index finger of the user's right hand at one end522and one or more of user's finger pads at other end520to facilitate grip, as well as encourages lift of the cap500without torquing the button514. The dimensions and shapes of the ends520and522of the pull member506and the surface area of the pull member504can be configured to accommodate different user hand and finger ergonomics, depending on where insertion mechanism and therefore button safety cap500are deployed on the medication delivery device (e.g., pump502).

While various embodiments have been shown and described, it will be understood by those skilled in the art that various changes and modifications can be made without departing from the scope of the invention as defined in the appended claims.