Methods, apparatuses, and uses for infusion pump fluid pressure and force detection

• US 6,659,980 B2
• Filed: 11/22/2002
• Issued: 12/09/2003
• Est. Priority Date: 03/29/2000
• Status: Expired due to Term

• Current Assignee: Andrew J. Scherer, Bradley J. Sargent, James D. Causey , III, Rex O. Bare, Sheldon B. Moberg
• Original Assignee: Andrew J. Scherer, Bradley J. Sargent, James D. Causey , III, Rex O. Bare, Sheldon B. Moberg
• Inventors: Moberg, Sheldon B., Bare, Rex O., Scherer, Andrew J., Causey, James D. III, Sargent, Bradley J.
• Primary Examiner(s): Ganey, Steven J.
• Application Number:
  US10/302,002
• Publication Number:
  US 20030073954A1
• Time in Patent Office: 382 Days
• Field of Search: 604/31, 604/65, 604/67, 604/154, 604/155, 604/153, 417/18, 417/474
• US Class Current: 604/154
• CPC Class Codes: A61M 2005/14264 with means for compensating influence from the environment
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 2205/33 Controlling, regulating or measuring
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 5/1456 with a replaceable reservoir comprising a piston rod to be moved into the reservoir, e.g. the piston rod is part of the removable reservoir
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/16831 Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066
• CPC Class Codes: A61M 5/1684 by detecting the amount of infusate remaining, e.g. signalling end of infusion
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence

Abstract

An occlusion detection system detects an occlusion in a fluid path of an infusion pump. The infusion pump is for delivering fluid to a user. The infusion pump includes a housing, a motor, a reservoir, one or more drive train components, a sensor, and an electronics system. The motor is contained within the housing. The reservoir contains the fluid to be delivered. The one or more drive train components react to stimulus from the motor to force the fluid from the reservoir into the user. The sensor is positioned to measure a parameter associated with the motor or a drive train component, and the sensor produces three or more output levels across a range of measurements. The electronics system processes the sensor output levels to declare when an occlusion exists.

Claims

1. A method of detecting an occlusion in an infusion pump for infusing fluid into a body of a user, the method comprising the steps of:

obtaining a measurement from a sensor before each fluid delivery;

calculating a slope of a line using two or more measurements, wherein the two or more measurements are not consecutive;

comparing the slope to a slope threshold;

incrementing a slope counter when the slope exceeds the slope threshold; and

declaring an occlusion when the slope counter exceeds a slope detection count.

2. The method according to claim 1, wherein the slope is an average slope.

3. The method according to claim 2, wherein the average slope is calculated using a previous average slope, a weighting factor, and a current slope.

4. The method according to claim 2, wherein the average slope is calculated using a least squares lines fit.

5. The method according to claim 2, wherein the step of calculating the slope of the line further comprises the steps of:

averaging two or more groups of measurements; and

calculating the slope of the line using the two or more groups of averaged measurements.

6. The method according to claim 1, wherein the slope is a current slope.

7. The method according to claim 1, comprising the step of restarting the slope counter when the slope is below the slope threshold.

8. The method according to claim 1, further comprising the step of comparing the most recent measurement to a measurement threshold, wherein an occlusion is declared when the slope counter exceeds the slope detection count and the most recent measurement exceeds the measurement threshold.

9. The method according to claim 1, further comprising the steps of:

comparing the most recent measurement to a measurement threshold; and

incrementing a measurement counter when the most recent measurement exceeds the measurement threshold, wherein an occlusion is declared when the slope counter exceeds the slope detection count and the measurement counter exceeds a measurement detection count.

10. An occlusion detection system for detecting an occlusion in an infusion pump for infusing fluid into a body of a user, the occlusion detection system comprising:

obtaining means for obtaining a measurement from a sensor before each fluid delivery;

calculating means for calculating a slope of a line using two or more measurements, wherein the two or more measurements are not consecutive;

comparing means for comparing the slope to a slope threshold;

incrementing means for incrementing a slope counter when the slope exceeds the slope threshold; and

declaring means for declaring an occlusion when the slope counter exceeds a slope detection count.

11. The occlusion detection system according to claim 10, wherein the slope is an average slope.

12. The occlusion detection system according to claim 10, wherein the slope is a current slope.

13. The occlusion detection system according to claim 10, further comprising means for restarting the slope counter when the slope is below the slope threshold.

15. The occlusion detection system according to claim 10, further comprising:

means for comparing the most recent measurement to a measurement threshold; and

means for incrementing a measurement counter when the most recent measurement exceeds the measurement threshold, wherein the declaring means declares an occlusion when the slope counter exceeds the slope detection count and the measurement counter exceeds a measurement detection count.

14. The occlusion detection system according to claim further comprising means for comparing the most recent measurement to a measurement threshold, wherein the declaring means declares an occlusion when the slope counter exceeds the slope detection count and the most recent measurement exceeds the measurement threshold.

16. An occlusion detection system for detecting an occlusion in an infusion pump with a reservoir containing fluid for infusing the fluid into a body of a user, the occlusion detection system comprising:

a housing;

a motor contained within the housing;

one or more drive train components that react to stimulus from the motor to force the fluid from the reservoir into the body of the user;

a sensor that is positioned to measure a parameter associated with the motor or at least one of the drive train components; and

an electronics system that obtains a measurement from the sensor before each fluid delivery, calculates a slope of a line using two or more measurements wherein the two or more measurements are not consecutive, compares the slope to a slope threshold, increments a slope counter when the slope exceeds the slope threshold, and declares an occlusion when the slope counter exceeds a slope detection count.

17. The occlusion detection system according to claim 16, wherein the slope is an average slope.

18. The occlusion detection system according to claim 16, wherein the slope is a current slope.

19. The occlusion detection system according to claim 16, wherein the electronics system further restarts the slope counter when the slope is below the slope threshold.

20. The occlusion detection system according to claim 16, wherein the electronics system further compares the most recent measurement to a measurement threshold, and declares an occlusion when the slope counter exceeds the slope detection count and the most recent measurement exceeds the measurement threshold.

21. The occlusion detection system according to claim 16, wherein the electronics system further compares the most recent measurement to a measurement threshold, increments a measurement counter when the most recent measurement exceeds the measurement threshold, and declares an occlusion when the slope counter exceeds the slope detection count and the measurement counter exceeds a measurement detection count.