Methods and apparatuses for detecting occlusions in an ambulatory infusion pump

Abstract

An improved pump, reservoir and reservoir piston are provided for controlled delivery of fluids. A motor is operably coupled to a drive member, such as a drive screw, which is adapted to advance a plunger slide in response to operation of the motor. The plunger slide is removably coupled to the piston. A method, system, and an article of manufacture for automatically detecting an occlusion in a medication infusion pump is provided. The electrical current to an infusion pump is measured. Based on measurements of one or more variables, the infusion pump detects whether there is an occlusion in the system. The methods of detecting occlusions may be dynamic.

Description

RELATED APPLICATIONS[0001]This is a divisional of U.S. patent application Ser. No. 11 / 323,104, filed Dec. 30, 2005, which is a continuation-in-part application claiming priority from U.S. patent application Ser. No. 10 / 691,187, filed Oct. 22, 2003, now U.S. Pat. No. 7,193,521, which is a continuation-in-part claiming priority from U.S. patent application Ser. No. 09 / 698,783, filed Oct. 27, 2000, now U.S. Pat. No. 6,800,071, which claims priority from U.S. patent application Ser. No. 09 / 429,352, filed Oct. 28, 1999, now U.S. Pat. No. 6,248,093, which claims priority from provisional patent application No. 60 / 106,237, filed Oct. 29, 1998, all of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates generally to improvements in infusion pumps such as those used for controlled delivery of medication to a patient. More specifically, this invention relates to improved methods and apparatuses for detecting errors i...

AI Technical Summary

Benefits of technology

The present invention provides an improved apparatus for dispensing medication fluid. The apparatus includes a reservoir and a movable piston adapted for use with a pump drive system. The piston has a first member and a second member, with the second member being made of a material having a higher stiffness than the first member. The piston is designed to form a fluid-tight barrier in the reservoir and can be releasably coupled to the pump drive system. The second member is in a generally parallel, spaced-apart relationship with the first member and is made of a material having a higher stiffness than the first member. The second member is adapted to contact the fluid to complete the fluid-tight barrier in the reservoir. The method of coupling the actuator to the reservoir piston includes measuring the axial force on the plunger slide and detecting when the plunger slide is seated in the reservoir based on the current measurements. The apparatus also includes detecting occlusions using at least two values of the pump system and calculating the average current or motor drive time to indicate when the plunger slide is seated in the reservoir.

Problems solved by technology

Solenoid based drive systems, on the other hand, often must be reset manually, which in turn makes water resistant construction of the pump housing more difficult.

This external arrangement occupies a substantial volume which can increase the overall size of the pump.

While the in-line drive system of FIG. 3a achieves a more compact physical pump size, there are problems associated with the design.

This results in a relatively expensive disposable item due to the number of components which go into its construction.

Any water which might come in contact with the drive screw 305 may result in corrosion or contamination which would affect performance or result in drive failure.

The design of FIG. 3a further gives rise to problems associated with position detection of the piston head 304.

The construction of pumps to be water resistant can give rise to operational problems.

Should the pressure in the housing exceed external atmospheric pressure, the resulting forces could cause the reservoir piston to be driven inward thus delivering unwanted medication.

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