Fluid delivery device, transcutaneous access tool and fluid drive mechanism for use therewith

A fluid delivery device comprising a fluid reservoir; a transcutaneous access tool fluidly coupled to the fluid reservoir; and a drive mechanism for driving fluid from the reservoir, the drive mechanism comprising a plunger received in the reservoir; a leadscrew extending from the plunger; a nut threadably engaged with the leadscrew; a drive wheel; and a clutch mechanism coupled to the drive wheel, wherein the clutch mechanism is configured to allow the nut to pass through when disengaged and is configured to grip the nut when engaged such that the drive wheel rotates the nut to advance the drive rod and the plunger into the reservoir.

TECHNICAL FIELD

The present invention relates to fluid delivery devices for delivering therapeutic liquids to a patient, and more particularly, to an infusion pump for delivering therapeutic liquids to a patient.

BACKGROUND INFORMATION

Fluid delivery devices have numerous uses such as delivering a liquid medicine or other therapeutic fluid 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.

Some infusion pumps have been designed to be relatively small, low cost, light-weight, and easy-to-use. One example of such a pump is the OMNIPOD® insulin infusion pump available from Insulet Corporation. Examples of infusion pumps are also described in greater detail, for example, in U.S. Pat. Nos. 7,128,727; 7,018,360; and 7,144,384 and U.S. Patent Application Publication Nos. 2007/0118405, 2006/0282290, 2005/0238507, and 2004/0010207, which are fully incorporated herein by reference. These pumps include insertion mechanisms for causing a transcutaneous access tool, such as a needle and/or soft cannula, to be inserted into a patient. Although such pumps are effective and provide significant advantages over other insulin infusion pumps, the design of the insertion mechanism may be improved, for example, to reduce the size of the pump, to improve the comfort to the user, and/or to incorporate continuous glucose monitoring (CGM). These pumps also include fluid driving mechanisms for driving fluid from a reservoir through the transcutaneous access tool. The fluid driving mechanisms may also be improved to facilitate assembly and use of the pump.

SUMMARY

The present disclosure provides various fluid delivery devices to deliver a liquid medicine or other therapeutic fluid to a patient subcutaneously. In certain embodiments the fluid delivery device may comprise an ambulatory insulin infusion device to administer insulin to a patient. The fluid delivery device may include one or more batteries for providing a power source, a fluid reservoir for holding a fluid, a fluid drive mechanism for driving the fluid out of the reservoir, a fluid passage mechanism for receiving the fluid from the reservoir and passing the fluid to a destination via a transcutaneous access tool, and a transcutaneous access tool insertion mechanism for deploying the transcutaneous access tool.

In certain embodiments, the drive mechanism may comprise a clutch mechanism. As explained herein, by using a clutch mechanism, the number of fluid path prime pulses to prime the pump may be reduced and a full and proper priming of the fluid path before placement on the body may be better assured. The clutch mechanism may also be made suitable for other drug applications without significant redesign, and be more easily inspected than conventional drive mechanisms for infusion devices.

In certain embodiments, the fluid delivery device may comprise a fluid reservoir; a transcutaneous access tool fluidly coupled to the fluid reservoir; and a drive mechanism for driving fluid from the reservoir. The drive mechanism may comprise a plunger received in the reservoir; a leadscrew extending from the plunger; a nut threadably engaged with the leadscrew; a drive wheel; and a clutch mechanism coupled to the drive wheel, wherein the clutch mechanism is configured to allow the nut to pass through the clutch mechanism when disengaged and is configured to grip the nut when engaged such that the drive wheel rotates the nut to advance the leadscrew and the plunger into the reservoir.

In certain embodiments, the fluid delivery device may comprise a fluid reservoir; a transcutaneous access tool fluidly coupled to the fluid reservoir; and a drive mechanism for driving fluid from the reservoir The drive mechanism may comprise a plunger received in the reservoir; an elongated assembly comprising a first elongated member and a second elongated member; the first elongated member extending from the plunger; the second elongated member coupled to the first elongated member; a drive wheel; and a clutch mechanism coupled to the drive wheel, wherein the clutch mechanism is configured to allow the second elongated member to pass through when disengaged and is configured to grip the second elongated member when engaged such that the drive wheel rotates the second elongated member to advance the first elongated member and the plunger into the reservoir.

In certain embodiments, a method of operating a foregoing fluid delivery device may comprise providing the fluid delivery device; holding the clutch mechanism in a disengaged position; filling the fluid reservoir with fluid; passing the second elongated member through the clutch mechanism such that the plunger is retracted within the reservoir; releasing the clutch mechanism from the disengaged position; and engaging the clutch mechanism with the second elongated member.

DETAILED DESCRIPTION

A fluid delivery device, consistent with embodiments of the present disclosure, may be used to deliver a therapeutic fluid (e.g. a liquid medicine) to a patient via a transcutaneous access tool, such as a needle/trocar and/or a cannula. A transcutaneous access tool insertion mechanism may be used to deploy the transcutaneous access tool, for example, by inserting and retracting a needle/trocar in a single, uninterrupted motion. The insertion mechanism may also provide an increasing insertion force as the needle/trocar moves in the insertion direction. The fluid delivery device may also include a clutch mechanism to facilitate filling a reservoir and engagement of a drive mechanism for driving fluid out of the reservoir. In certain embodiments, the fluid delivery device may comprise an ambulatory insulin infusion device.

In other embodiments, a fluid delivery device may be used to deliver a therapeutic fluid to a patient with integrated monitoring, such as continuous glucose monitoring (CGM). In these embodiments, the fluid deliver device may include a transcutaneous access tool configured to introduce a monitoring test strip through the skin of the patient, for example, using one or more needles, cannulas and/or trocars.

Referring toFIGS. 1-6, one embodiment of a fluid delivery device100is shown and described. In the exemplary embodiment, the fluid delivery device100is used to subcutaneously deliver a fluid, such as a liquid medicine (e.g. insulin), to a person or an animal. Those skilled in the art will recognize that the fluid delivery device100may be used to deliver other types of fluids. The fluid delivery device100may be used to deliver fluids in a controlled manner, for example, according to fluid delivery profiles accomplishing bolus requirements, continuous infusion and variable flow rate delivery.

According to one embodiment, the fluid delivery device100may include one or more batteries110for providing a power source, a fluid reservoir130for holding a fluid, a fluid drive mechanism150for driving the fluid out of the reservoir130, a fluid passage mechanism170for receiving the fluid from the reservoir130and passing the fluid to a destination via a transcutaneous access tool172, and a transcutaneous access tool insertion mechanism180for deploying the transcutaneous access tool172. The fluid delivery device100may include a circuit board101with control circuitry for controlling the device and a chassis102that provides mechanical and/or electrical connections between components of the fluid deliver device100. The fluid delivery device100may also include a housing104to enclose the circuit board101, the chassis102, and the components110,130,150,170,180.

The fluid delivery device100may also include integrated monitoring such as continuous glucose monitoring (CGM). A monitor test strip120coupled to a monitor (not shown) in the device100may be introduced by the transcutaneous access tool172subcutaneously. One example of the monitor test strip is a CGM test strip (such as the type available from Nova Biomedical) which may be understood as a glucose sensor configured to test for a concentration level of glucose in the blood of a patient. The fluid delivery device100may be configured to receive data from the monitoring test strip concerning a glucose level of the patient, and determining an output of insulin from the reservoir based on the glucose level.

The transcutaneous access tool172includes an introducer trocar or needle174at least partially positioned within a lumen175of a cannula176(e.g., a soft flexible cannula), which is capable of passing the fluid into the patient. In particular, the introducer needle/trocar174may initially penetrate the skin such that both the introducer needle/trocar174and the cannula176are introduced (inserted) into the patient, and the introducer needle/trocar174may then be retracted within the cannula176such that the cannula176remains inserted. A fluid path, such as tubing178, fluidly couples the reservoir130to the lumen175of cannula176of the transcutaneous access tool172.

The transcutaneous access tool insertion mechanism180is coupled to the transcutaneous access tool172to deploy the transcutaneous access tool172, for example, by inserting the needle/trocar174and cannula176through the skin of a patient and retracting the needle/trocar174. In the illustrated embodiment, the insertion mechanism180includes a spring-biased linkage mechanism182and sliding members184,186coupled to the needle/trocar174and cannula176, respectively, for moving the needle/trocar174and cannula176in the insertion direction and for moving the needle/trocar174in the retraction direction. In a single, uninterrupted motion, the spring-biased linkage mechanism182moves from a pre-deployment position (FIG. 1) with both needle/trocar174and cannula176retracted (FIG. 2) to an intermediate position (FIG. 3) with both needle/trocar174and cannula176inserted (FIG. 4) to a post-deployment position (FIG. 5) with the needle/trocar174retracted and the cannula176inserted (FIG. 6).

Referring toFIGS. 7-12, one embodiment of the fluid drive mechanism150uses a clutch mechanism160to facilitate filling of the reservoir130and engagement of the fluid drive mechanism150for driving fluid out of the reservoir130. The fluid drive mechanism150includes a first threaded member in the form of an elongated shaft such as a threaded drive rod or leadscrew152, with external threads extending from a plunger136received in the reservoir130and sealed with an o-ring137against the inside surface of the reservoir130. The leadscrew152and plunger136may be an inseparable, insert-molded assembly. A second threaded member in the form of an elongated shaft such as a tube nut154with internal threads threadably engages the leadscrew152and may be driven by a drive wheel156via a clutch mechanism160.

When the reservoir130is empty (FIGS. 7 and 8), the plunger136is positioned at one end of the reservoir130such that the plunger136is extended and the clutch mechanism160is disengaged. In certain embodiments, the reservoir130may be filled with fluid, particularly insulin, by opening an inlet port to the reservoir130and pumping in the insulin under sufficient hydraulic pressure to retract the plunger136within the reservoir130. Thereafter, the inlet port may be closed. When the reservoir130is filled and the plunger136moves to the opposite (retracted) end of the reservoir130(FIG. 9), the clutch mechanism160remains disengaged to allow the tube nut154to pass into an elongated cylindrical bore (along the drive axis) of a hub of the drive wheel156. The clutch mechanism160may then be engaged (FIGS. 10-12) such that rotation of the drive wheel156causes the clutch mechanism160to rotate the tube nut154, which causes the leadscrew152to advance the plunger into the reservoir130to deliver the fluid from the reservoir130. In alternative embodiments, the reservoir130may be filled when the plunger136is already retracted.

In the illustrated embodiment, the clutch mechanism160includes a clutch spring162(e.g., a helical torsion spring) located in a counterbore at one end of the drive wheel156, adjacent the reservoir130. The inside diameter of the clutch spring162is larger than the outside diameter of the tube nut154when the clutch spring162is loaded, thereby disengaging the clutch spring162from the tube nut154and allowing the tube nut154to pass through the center aperture of the spring162and into the elongated bore of the drive wheel156. Alternatively, the inside diameter of the clutch spring162is smaller than the outside diameter of the tube nut154when the clutch spring162is unloaded, thereby engaging or gripping the tube nut154and allowing the drive wheel156to rotate the tube nut154. In the illustrated embodiment, prior to filing the reservoir130, the clutch spring162is held in the loaded, disengaged position by a spring latch164engaged with the drive wheel156(FIGS. 7-9). After the reservoir130has been filled, the clutch spring162may thus be engaged by rotating the drive wheel156until the spring latch164releases the clutch spring162(FIG. 10) allowing the clutch spring162to unload and grip the tube nut154(FIGS. 11 and 12), at which time fluid may be dispensed from the reservoir130with continued rotation of the drive wheel156.

As shown, the spring latch164may be biased by the clutch spring162such that as the drive wheel156rotates the spring latch164moves rotationally against a surface of a reservoir cap132until clutch spring162deflects the spring latch164into a window133in the reservoir cap132. When the spring latch164moves into the window133, the end of the clutch spring162held by the spring latch164is released, thus engaging the clutch mechanism160. When the clutch spring162is engaged, the drive wheel156contacts an end163of the clutch spring162to create a thrust on the clutch spring162that causes the clutch spring162to rotate the tube nut154. The fluid drive mechanism150may also use other clutch mechanisms capable of allowing the tube nut154or other type of nut or threaded member to pass through the clutch mechanism and then being activated to engage the nut or threaded member.

In the illustrated embodiment, the drive wheel156includes ratchets157that are engaged by an actuator158to incrementally drive the wheel156and advance the plunger136into the reservoir130. Examples of this actuation mechanism are described in greater detail in U.S. Patent Application Publication No. 2005/0238507, which is fully incorporated herein by reference.

By using a clutch mechanism, the engagement between the leadscrew and the nut occurs at assembly, and thus no rotation is needed for the nut to engage the leadscrew by operation of the device. This reduces the number of fluid path prime pulses to prime the pump and assures a full and proper priming of the fluid path before placement on the body. The clutch mechanism also enables the changing of thread pitch for other drug applications without a need to redesign the tilt nut used in fluid driving mechanisms in other existing pumps. The components of the clutch mechanism are also more easily inspected than the tilt nut assembly.