The present invention relates to fluid delivery devices and more particularly, to an infusion pump for delivering therapeutic liquids to a patient.
Fluid delivery devices have numerous uses such as delivering a liquid medicine to a patient subcutaneously. In a patient with diabetes mellitus, for example, ambulatory infusion pumps have been used to deliver insulin to a patient. These ambulatory infusion pumps have the ability to offer sophisticated fluid delivery profiles including variable basal rates and bolus requirements. The ability to carefully control drug delivery can result in better efficacy of the drug and therapy and less toxicity to the patient.
Some existing ambulatory infusion pumps include a reservoir to contain the liquid medicine and use electromechanical pumping or metering technology to deliver the liquid medicine via tubing to a needle and/or soft cannula that is inserted subcutaneously into the patient. These existing devices allow control and programming via electromechanical buttons or switches located on the housing of the device. The devices include visual feedback via text or graphic screens and may include alert or warning lights and audio or vibration signals and alarms. Such devices are typically 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. Preparing these devices for infusion can be difficult and require the patient to carry both the intended medication as various accessories. Many existing devices also require specialized care, maintenance, and cleaning to assure proper functionality and safety for their intended long-term use. Due to the complexity and high cost of existing devices many patients who would benefit from an ambulatory infusion pump are, nonetheless using inferior forms of therapy.
Accordingly, there is a need for a fluid delivery device with a reduced size and complexity and that is relatively inexpensive to manufacture.
These and other features and advantages will be better understood by reading the following detailed description, taken together with the drawings wherein:
Referring to
According to one embodiment, the fluid delivery device 200 may include one or more batteries 210 for providing a power source, a fluid reservoir 230 for holding a fluid, a fluid driving mechanism 250 for driving the fluid out of the reservoir 230, a fluid passage mechanism 270 for receiving the fluid from the reservoir 230, a fluid passage mechanism 270 for receiving the fluid from the reservoir 230 and passing the fluid to a destination, and a circuit board 290 with control circuitry for controlling the device. The fluid delivery device 200 may include a chassis 100 that provides mechanical and/or electrical connections between components of the fluid deliver device 200. One example of the chassis 100 is disclosed in greater detail in U.S. patent application Ser. No. ______ (Attorney Docket No. INSL-165), which is filed concurrently herewith and incorporated herein by reference. The fluid delivery device 200 may also include a housing 202 to enclose the components 210, 230, 250, 270, 290 and the chassis 100.
One embodiment of the reservoir 230 includes an outlet port 232 for allowing fluid to exit the reservoir 230. The reservoir 230 may also include an inlet port 234 for allowing the reservoir 230 to be filled with fluid. One embodiment of the reservoir 230 is disclosed in greater detail in U.S. patent application Ser. No. ______ (Attorney Docket No. INSL-165), which is filed concurrently herewith and has been incorporated by reference.
One embodiment of the fluid passage mechanism 270 includes a transcutaneous access tool 272, such as a needle and/or soft cannula, which is capable of penetrating the skin of a patient and passing the fluid into the patient. A fluid path such as tubing (not shown) may be used to fluidly couple the reservoir 230 to the transcutaneous access tool 272. The access tool 272 is mounted to an insertion mechanism, which may include sliding carriages 274, 275, one or more springs 276, and a release member 280 (see
Referring to
One embodiment of the drive wheel 256 includes first and second ratchet wheel portions 258a, 258b and a hub 254 between the ratchet wheel portions 258a, 258b. The drive wheel 256 may be rotatably supported by the chassis 100. In particular, the hub 254 may be supported by one or more bearing surfaces 158a-c on the chassis 100 (see
An actuation mechanism is used to engage and incrementally rotate the drive wheel 256. One embodiment of an actuating mechanism for the drive wheel 256 may include a linear actuator. A preferred linear actuator comprises a shape memory allow wire. As shown in
As shown in
The pivotable drive engaging member 262 may be pivotably coupled to a pivot point 162 on the chassis 100, which also acts as an electrical contact point. One embodiment of the pivotable drive engaging member 262 includes arms 264a, 264b that engage teeth on the ratchet wheel portions 258a, 258b and incrementally rotating the drive wheel 256 when the pivotable drive engaging member 262 pivots. The pivotable drive engaging member 262 may also include legs 268a, 268b that contact points 164a, 164b on the chassis 100 when the pivotable drive engaging member 262 pivots. Alternatively, the pivotable drive engaging member 262 may only include one arm and one leg.
The contact points 160a, 160b, 162, 164a, 164b provide an electrical connection between the components of the actuating mechanism and the control circuitry (not shown). In one embodiment, this electrical connection is provided via conductive paths extending along the chassis 100. The contact points 160a, 160b electrically connect the SMA wire portions 260a, 260b to actuator conductive paths 194a, 194b on the chassis 100. The pivot point 162 electrically connects the pivotable drive engaging member 262 to a common ground conductive path 195 on the chassis 100. The contact points 164a, 164b electrically connect the pivotable drive engaging member 262 to actuator conductive paths 196a, 196b. The conductive paths along the chassis 100 are shown and described in greater detail in U.S. patent application Ser. No. ______ (Attorney Docket No. INSL-165), which is filed concurrently herewith and has been incorporated by reference. Those skilled in the art will recognize other means for electrically connecting the components of the actuating mechanism to the control circuitry.
Referring to
To initiate another pulse, the control circuitry applies current to the second SMA wire portion 260b, for example, via the conductive path 194b and the contact point 160b (shown in
Each incremental rotation of the drive wheel 256 advances the plunger in the reservoir 230 to cause a discrete amount of fluid to be dispensed. The discrete amount of fluid to be dispensed is a function of the lead screw pitch (i.e., threads/inch), the number of teeth on the ratchet wheel (that is, ratchet wheel tooth size) and the diameter of the fluid reservoir. In a preferred embodiment, for delivering U100 insulin for treatment of Type I diabetes, the discrete amount of fluid to be dispensed is between about 0.25 μL and about 0.5 μL. The control circuitry alternates energizing the SMA wire portions 260a, 260b until a desired amount of fluid has been dispensed. One example of the control circuitry and control method is disclosed in greater detail in U.S. patent application Ser. Nos. 10/835727, 10/836525, and 10/836535, which are fully incorporated herein by reference.
Examples of alternative fluid driving mechanisms and actuation mechanisms that may be used in the fluid delivery device 200 are disclosed in U.S. Pat. Nos. 6,656,158 and 6,656,159 and U.S. patent application Ser. No. 10/704,291, all of which are incorporated herein by reference.
The fluid delivery device 200 may also include one or more sensors to monitor operation of the fluid driving mechanism 250. For example, fill sensors may be used to sense a level of fluid in the reservoir 230 when filling the reservoir 230 with fluid and/or dispensing fluid from the reservoir 230. Rotational sensors may be used to sense that the driving mechanism 250 is operating in accordance with expectations.
Referring to
At the point when the drive rod 252 causes the fill sensor bar 292 to engage the contact point 165, the plunger 236 is at a predetermined location in the reservoir 230 and the amount of fluid in the reservoir 230 is known. The fill sensor may be used when filling the fluid delivery device 200 to indicate that the reservoir has been filled to a predetermined amount and/or to “wake up” the control circuitry in the fluid delivery device 200. Thus, in a preferred embodiment of the present invention, before the fill sensor has been triggered, the fluid delivery device control circuitry is in a rest state characterized by minimal activity and power consumption. In such an embodiment, once the fill sensor is triggered, the control circuitry enters an active state characterized by higher activity and power consumption. The fill sensor may also be used when delivering the fluid to indicate that the predetermined amount of fluid remains in the reservoir. Although one embodiment of a fill sensor is shown and described, other configurations may be used to activate a fill sensor signal in response to a predetermined position of the drive rod. Referring to
Referring to
As shown in
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One embodiment of the thread engaging mechanism 240 includes a tilt nut 242 having threaded regions 244a, 244b. The tilt nut 242 may include one or more pivot pins 246 that pivotably support the tilt nut 242 within the drive wheel 256 (see
According to one embodiment, shown in
Although the illustrated embodiment shows the components mechanically secured to and electrically connected to a single chassis, the components of the fluid delivery device consistent with embodiments of the present invention may be mechanically secured and/or electrically connected to other structures such as separate structural members or the housing.
In summary, a fluid delivery device, consistent with one embodiment of the present invention, includes a fluid reservoir, a plunger received in the fluid reservoir, a threaded drive rod coupled to the plunger to advance the plunger in the fluid reservoir, and a drive wheel coupled to the threaded drive rod. The fluid delivery device also includes a pivotable drive engaging member including at least one arm configured to engage and incrementally rotate the drive wheel and at least first and second shape memory alloy (SMA) wire portions coupled to the pivotable drive engaging member to pivot the pivotable drive engaging member. In response to being charged, the first SMA wire portion is configured to contract and pull the pivotable drive engaging member in a first direction and the second SMA wire portion is configured to contract and pull the pivotable drive engaging member in a second direction.
Consistent with another embodiment of the present invention, a fluid delivery device includes a fluid reservoir, a plunger received in the fluid reservoir, a threaded drive rod coupled to the plunger to advance the plunger in the fluid reservoir, a drive wheel coupled to the threaded drive rod, and an actuating mechanism configured to engage and incrementally rotate the drive wheel. This embodiment of the fluid delivery device also includes a rotational sensor extending across the drive wheel. The drive wheel is configured to engage the rotational sensor during rotation to cause the rotational sensor to contact a conductive path activating an electrical signal indicating rotation of the drive wheel.
Consistent with a further embodiment of the present invention, a fluid delivery device includes a fluid reservoir, a plunger received in the fluid reservoir, a threaded drive rod coupled to the plunger to advance the plunger in the fluid reservoir, a drive wheel configured to threadably engage the threaded drive rod to impart linear motion to the threaded drive rod when the drive wheel rotates, and an actuating mechanism configured to engage and incrementally rotate the drive wheel. This embodiment of the fluid delivery device also includes a fill sensor extending across a path of the threaded drive rod. The threaded drive rod is configured to engage the fill sensor when the plunger is at a predetermined location in the fluid reservoir to cause the fill sensor to contact an electrically conductive path enabling an electrical signal indicating an amount of fluid in the fluid reservoir.
Consistent with yet another embodiment, a fluid delivery device includes a fluid reservoir, a plunger received in the fluid reservoir, and a threaded drive rod coupled to the plunger to advance the plunger in the fluid reservoir. In this embodiment, the fluid delivery device also includes a drive wheel configured to receive the threaded drive rod and including a thread engaging mechanism configured to move from a non-thread-engaging position to a thread engaging position in which the thread engaging mechanism engages threads of the threaded drive rod. The drive wheel is configured to impart linear motion to the threaded drive rod when the thread engaging mechanism is in the thread engaging position and the drive wheel rotates.
While the principles of the invention have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention. Other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims.
This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 10/704291, filed on Nov. 7, 2003, which is a continuation-in-part of co-pending U.S. patent application Ser. No. 10/128,205, which are assigned to the assignee of the present application and are incorporated herein by reference. This application is related to U.S. patent application Ser. No. ______ (Attorney Docket No. INSL-165) entitled CHASSIS FOR FLUID DELIVERY DEVICE, which is filed concurrently herewith, assigned to the assignee of the present application, and incorporated herein by reference.
Number | Date | Country | |
---|---|---|---|
Parent | 10704291 | Nov 2003 | US |
Child | 10907287 | Mar 2005 | US |
Parent | 10128205 | Apr 2002 | US |
Child | 10704291 | Nov 2003 | US |