DETECTION OF INFUSION PUMP CONDITIONS

• US 20140276538A1
• Filed: 03/15/2013
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Tandem Diabetes Care Incorporated
• Original Assignee: Tandem Diabetes Care Incorporated
• Inventors: Michaud, Michael
• Granted Patent: US 9,180,243 B2
• Time in Patent Office: Days
• US Class Current: 604/500
• CPC Class Codes: A61M 2005/14264 with means for compensating influence from the environment
• CPC Class Codes: A61M 2005/14268 with a reusable and a disposable component
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3351 Controlling upstream pump pressure
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/3372 Temperature compensation
• CPC Class Codes: A61M 2205/3389 Continuous level detection A61M2205/3393 takes precedence
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2209/045 for filling, e.g. for filling reservoirs
• CPC Class Codes: A61M 5/14216 Reciprocating piston type
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• 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

Abstract

An ambulatory infusion system and a method of operating including a disposable infusion cartridge having a collapsible reservoir and a substantially rigid shell disposed over the collapsible reservoir having an interior volume, a pump device, a pressure sensor in communication with the interior volume and a processor. The method includes actuating the pressure sensor to take pressure measurements at regular time intervals; periodically assessing a preselected number of the pressure measurements with statistical analysis to identify statistical measures associated with the pressure measurements; and using the statistical measures to assess the status of the flexible reservoir and the pump device.

Claims

1. An ambulatory infusion system, comprising:

an infusion cartridge, the infusion cartridge including a collapsible reservoir for containing a fluid and a substantially rigid shell disposed over the collapsible reservoir and forming an interior volume between an outside surface of the collapsible reservoir and an inside surface of the shell;

a pump device configured to selectively receive the infusion cartridge and cooperate with the infusion cartridge to deliver fluid from the reservoir to the patient;

a pressure sensor located in one of the infusion cartridge and the pump, the pressure sensor in communication with the interior volume of the infusion cartridge; and

a processor located in one of the infusion cartridge and the pump, wherein the processor is programmed with an algorithm to perform the following;

actuating the pressure sensor to take pressure measurements at regular time intervals;

periodically assessing a preselected number of the pressure measurements with statistical analysis to identify statistical measures associated with the pressure measurements; and

using the statistical measures to assess the status of the flexible reservoir and the pump device.

2. The ambulatory infusion system as claimed in claim 1, wherein the pump device further comprises a spool including a main section and a distal section;

and

wherein the processor is further programmed with an algorithm to perform the following;

commanding movement of the main section and the distal section to a ready to dispense position;

assessing the statistical measures during the time following the movement of the main section and the distal section to a ready to dispense position including standard deviation for a plurality of time periods following a plurality of movements of the main section and the distal section to a ready to dispense position;

determining an expected value for the standard deviation;

identifying occasions wherein the standard deviation vary substantially from the expected value.

3. The ambulatory infusion system as claimed in claim 2, wherein the processor is further programmed with an algorithm to perform the following:

associating the occasions wherein the standard deviation varies substantially from the expected value as being indicative of the flexible reservoir being filled to or near its maximum level or capacity.

4. The ambulatory infusion system as claimed in claim 3, wherein the processor is further programmed with an algorithm to perform the following:

presenting a message that the flexible reservoir is filled to or near its maximum level or capacity.

5. The ambulatory infusion system as claimed in claim 3, wherein the processor is further programmed with an algorithm to perform the following:

associating the flexible reservoir being filled to or near its maximum level or capacity with a risk that autodispensing may occur.

6. The ambulatory infusion system as claimed in claim 1, wherein the processor is further programmed with an algorithm to perform the following:

assessing the statistical measures including standard deviation for a plurality of time periods;

determining an expected value for the standard deviation; and

identifying occasions wherein the standard deviation vary substantially from the expected value.

7. The ambulatory infusion system as claimed in claim 1, wherein the processor is further programmed with an algorithm to perform the following:

associating the occasions wherein the standard deviation vary substantially from the expected value as being indicative of external factors including transient temperature changes and mechanical pressure applied to the disposable infusion cartridge; and

rejecting the measurements made on the occasions wherein the standard deviation vary substantially from the expected value or assigning the measurements made on the occasions wherein the standard deviation vary substantially from the expected value a lesser weight than measurement that are near the expected value.

8. A computer implemented method of monitoring an ambulatory infusion device, the ambulatory infusion device comprising:

an infusion cartridge, the infusion cartridge including a collapsible reservoir for containing a fluid and a substantially rigid shell disposed over the collapsible reservoir and forming an interior volume between an outside surface of the collapsible reservoir and an inside surface of the shell;

a pump device configured to selectively receive the infusion cartridge and cooperate with the infusion cartridge to deliver fluid from the reservoir to the patient;

a pressure sensor located in one of the infusion cartridge and the pump, the pressure sensor in communication with the interior volume of the infusion cartridge; and

a processor located in one of the infusion cartridge and the pump, the method comprising;

actuating the pressure sensor to take pressure measurements at regular time intervals;

periodically assessing a preselected number of the pressure measurements with statistical analysis to identify statistical measures associated with the pressure measurements; and

using the statistical measures to assess the status of the flexible reservoir and the pump device.

9. The method as claimed in claim 8, further comprising commanding movement of a spool having a main section and the distal section to a ready to dispense position;

assessing the statistical measures during the time following the movement of the main section and the distal section to a ready to dispense position including standard deviation for a plurality of time periods following a plurality of movements of the main section and the distal section to a ready to dispense position;

determining an expected value for the standard deviation;

identifying occasions wherein the standard deviation vary substantially from the expected value.

10. The method as claimed in claim 9, further comprising associating the occasions wherein the standard deviation vary substantially from the expected value as being indicative of the flexible reservoir being filled to or near its maximum level or capacity.

11. The method as claimed in claim 10, further comprising presenting a message that the flexible reservoir is filled to or near its maximum level or capacity.

12. The method as claimed in claim 10, further comprising associating the flexible reservoir being filled to or near its maximum level or capacity with a risk that autodispensing may occur.

13. The method as claimed in claim 8, further comprising assessing the statistical measures including standard deviation for a plurality of time periods;

determining an expected value for the standard deviation; and

identifying occasions wherein the standard deviation vary substantially from the expected value.

14. The method as claimed in claim 8, associating the occasions wherein the standard deviation vary substantially from the expected value as being indicative of external factors including transient temperature changes and mechanical pressure applied to the infusion cartridge;

and

rejecting the measurements made on the occasions wherein the standard deviation vary substantially from the expected value or assigning the measurements made on the occasions wherein the standard deviation vary substantially from the expected value a lesser weight than measurement that are near the expected value.

15. The method as claimed in claim 8, further comprising commanding movement of a spool and spool distal section to a ready to fill position;

commanding movement of the main section and the distal section to a filled position;

commanding movement of the main section and the distal section from the filled position to a ready to dispense position;

commanding movement of the main section and the distal section from the ready to dispense position to a dispense position;

assessing the statistical measures for average pressure during a first time when the main section and the distal section are in the ready to fill position;

assessing the statistical measures for average pressure during a second time when the main section and the distal section are in the ready to fill position;

assessing the statistical measures for average pressure during a third time when the main section and the distal section are in the ready to dispense position;

assessing the statistical measures for average pressure during a fourth time when the main section and the distal section are in the ready to dispense position for a period of time;

calculating three volume measurements of volume of the collapsible reservoir including a first volume, a second volume and a third volume based on the average pressure during a first time, the average pressure during a second time, the average pressure during a third time and the average pressure during a fourth time; and

comparing the first volume, the second volume and the third volume to determine whether autodispensing has occurred.

16. The method as claimed in claim 15, further comprising identifying a circumstance wherein the first volume is greater than the second volume and the second volume is equal to the third volume as being indicative of proper operation;

and

identifying a circumstance wherein the first volume is greater than the second volume and the second volume is greater than the third volume as being indicative that autodispensing has occurred.

17. The method as claimed in claim 16, further comprising presenting a message or warning that autodispensing has occurred if autodispensing has been identified.

18. The method as claimed in claim 16, further comprising foregoing a future planned dispensing event if autodispensing has occurred.