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EP-3749390-B1 - METHODS AND SYSTEMS FOR DETECTING INFUSION PUMP CONDITIONS

EP3749390B1EP 3749390 B1EP3749390 B1EP 3749390B1EP-3749390-B1

Inventors

  • SEITZ, ALEXANDER
  • MICHAUD, MICHAEL
  • LAMB, PHILIP SVEN
  • BROWN, JUSTIN
  • KRUSE, GEOFFREY A.

Dates

Publication Date
20260506
Application Date
20190204

Claims (15)

  1. An ambulatory infusion pump system, comprising: a reservoir configured to contain a medicament, including a plunger at a proximal end of the reservoir and an outlet port at a distal end of the reservoir; a pushrod (206); a motor (201) mechanically linked to the pushrod and configured to mechanically cause linear motion of the pushrod (206) to contact and move the plunger to cause medicament to flow from the reservoir out of the outlet port to a patient; an optical encoder (240) configured to monitor a linear position of the pushrod (206); and a processor configured to control the motor (201) and pushrod (206) to cause delivery of medicament from the reservoir, wherein the processor is configured to: command the motor (201) to actuate to deliver medicament from the reservoir by advancing the pushrod (206) from a first linear position to a second linear position; monitor an amount of time it takes for the pushrod (206) to advance from the first linear position to the second linear position; compare the amount of time to an expected move completion time; and provide a notification to a user of an error if the amount of time is longer than the expected move completion time.
  2. The ambulatory infusion pump system of claim 1, wherein the processor is further configured to determine if the pushrod (206) moved from the first linear position to the second linear position.
  3. The ambulatory infusion pump system of claim 2, where if the pushrod (206) moved from the first linear position to the second linear position and the amount of time was longer than the expected move completion time, the processor is configured to notify a user of an error by notifying the user that an occlusion is present.
  4. The ambulatory infusion pump system of claim 2, wherein if the pushrod (206) did not move from the first linear position to the second linear position during the expected move completion time, the processor is further configured to determine an absolute position of the pushrod (206) relative to a fully retracted position and a fully extended position.
  5. The ambulatory infusion pump system of claim 4, wherein if the pushrod (206) is in the fully extended position and the pushrod (206) did not move from the first linear position to the second linear position during the expected move completion time, the processor is configured to notify a user of an error by notifying the user that the pushrod (206) has reached the fully extended position.
  6. The ambulatory infusion pump system of claim 4, wherein if the pushrod (206) is not in the fully extended position, the processor is configured to determine an amount of medicament remaining in the reservoir.
  7. The ambulatory infusion pump system of claim 6, wherein if the amount of medicament remaining in the reservoir is below a predetermined threshold, the processor is configured to notify a user of an error by notifying the user that the reservoir needs to be refilled.
  8. The ambulatory infusion pump system of claim 6, wherein if the amount of medicament remaining in the reservoir is not below a predetermined threshold, the processor is configured to notify a user of an error by notifying the user that a drive system error preventing the pushrod (206) from being linearly advanced is present.
  9. The ambulatory infusion pump system of any preceding claim, wherein the expected move completion time is an expected range of move completion times.
  10. The ambulatory infusion pump system of any preceding claim, wherein the optical encoder (240) monitors a linear position of the pushrod (206) by monitoring a rotational position of markings (242) on a drive tube (202) that rotates when the motor (201) is actuated to cause the linear motion of the pushrod (206).
  11. The ambulatory infusion pump system of claim 10, further comprising: a magnetic sensor (241) configured to monitor rotation of the drive tube (202) by sensing a magnet (243) disposed on the drive tube (202) when the drive tube (202) is rotated; and wherein the processor is configured to compare rotation of the drive tube (202) as monitored by the magnetic sensor (241) sensing the magnet (243) with rotation of the drive tube (202) as monitored by the optical encoder (240) sensing the markings (242) on the drive tube (202).
  12. The ambulatory infusion pump system of claim 11, wherein the processor is configured to compare rotation of the drive tube as monitored by the magnetic sensor (241) sensing the magnet (243) with rotation of the drive tube as monitored by the optical encoder (240) sensing markings (242) on the drive tube (202) by comparing a number of complete rotations of the drive tube (202) as monitored by the magnetic sensor (241) and the optical encoder (240).
  13. The ambulatory infusion pump system of claim 11, wherein the processor is configured to compare rotation of the drive tube (202) by comparing a number of markings (242) sensed on the drive tube (202) by the optical encoder (240) with an expected number of markings (242) expected to be detected for a given number of times the magnetic sensor (241) has sensed the magnet (243).
  14. The ambulatory infusion pump system of claim 13, wherein the expected number of markings (242) is a range of markings.
  15. The ambulatory infusion pump system of claim 11, wherein if the rotation of the drive tube (202) as monitored by the magnetic sensor (241) does not equal the rotation of the drive tube as monitored by the optical encoder (240), the processor is configured to at least one of issue an encoder alert, disable the motor (201) and initiate a pump self-test.

Description

RELATED APPLICATIONS The present application claims the benefit of U.S. Provisional Application No. 62/626,430 filed February 5, 2018 and U.S. Provisional Application No. 62/632,294 filed February 19, 2018. TECHNICAL FIELD The present invention relates to medical pumps for delivering medicament to a patient and, more specifically, to user-wearable infusion pumps for delivering medicament such as insulin to a patient. BACKGROUND There are many applications in academic, industrial, and medical fields that benefit from devices and methods that are capable of accurately and controllably delivering fluids, such as liquids and gases, that have a beneficial effect when administered in known and controlled quantities. Such devices and methods can be particularly useful in the medical field where treatments for many patients include the administration of a known amount of a substance at predetermined intervals. One category of devices for delivering such fluids is that of pumps that have been developed for the administration of insulin and other medicaments for those suffering from both Type 1 and Type 2 diabetes. Some pumps configured as portable infusion devices can provide continuous subcutaneous medicament injection and/or infusion therapy for the treatment of diabetes. Such therapy may include, e.g., the regular and/or continuous injection or infusion of insulin into the skin of a person suffering from diabetes and offer an alternative to multiple daily injections of insulin by an insulin syringe or an insulin pen. Such pumps can be ambulatory/portable infusion pumps that are worn by the user and may use replaceable cartridges. Examples of such pumps and various features that can be associated with such pumps include those disclosed in U.S. Patent Application Publication No. 2013/0053816; U.S. Patent No. 8,573,027; U.S. Patent No. 8,986,253; U.S. Patent Application Publication No. 2013/0324928; U.S. Patent Application Publication No. 2013/0331790; U.S. Patent No. 8,287,495; U.S. Patent Publication No. 2017/0049957; and U.S. Patent Publication No. 2016/0339172. One common type of ambulatory infusion pump utilizes an electromagnetic motor to rotate a lead screw that drives a syringe to cause medicament to be delivered from a medicament reservoir in the pump to a patient. Most such systems incorporate a gear reduction system to decrease the speed generated by the motor in order to increase the torque on the lead screw to a sufficient level to cause the medicament to be dispensed. Such systems generally employ a force sensor for detecting and monitoring pressure conditions in the syringe cartridge. However, this additional sensor requires additional space and electronics and represents an additional possible failure point in a complex electromechanical system. Another type of ambulatory infusion pump that has been developed utilizes piezoelectric elements to rotate a lead screw and drive a syringe that causes medicament to be delivered. One such pump, further details of which can be found in U.S. Patent Publication No. 2017/0049957 assigned to the assignee of the present application, does not requires a gear reduction system in order to drive the syringe. Therefore, this type of pump requires fewer parts and can be made smaller than pumps that utilize gear reduction systems. This type of pump can also employ an encoder system. The encoder system may in one example utilize an optical encoder integrated circuit that monitors markings configured radially around an outer surface of a cylindrical drive element in order to monitor a rotational position of the drive element. Document US 2017/049957 A1 discloses a patch pump which utilizes piezoelectricity to dispense medicament from a cartridge syringe to a patient. Document US 2005/020980 A1 discloses a pump system for an infusion system including a linear drive, which minimizes the space occupies by the pump components in a portable housing. Document US 2012/078216 A1 discloses ambulatory infusion pumps, pump assemblies, cartridges, baseplates, cannulas, insertion tools, and related components. Document US 2007/062250 A1 discloses systems and methods of detecting occlusions and fluid-loss conditions in an infusion pump. Document US 2012/192951 A1 discloses systems, devices and methods, including a system that includes a sensor configured to monitor at least one parameter associated with operation of a fluid delivery device, and a controller. Document WO 2016/061194 A1 discloses a flow control apparatus adapted for a feeding set having a housing capable of receiving at least a portion of the feeding set. SUMMARY Disclosed herein are systems and methods for monitoring performance of an ambulatory infusion pump. An ambulatory infusion pump can include a reservoir configured to contain a medicament including a plunger at a proximal end of the reservoir and an outlet port at a distal end of the reservoir. A motor can be configured to cause linear motion of a pushrod to conta