Fluid reservoir seating procedure for a fluid infusion device

• US 9,555,190 B2
• Filed: 02/13/2014
• Issued: 01/31/2017
• Est. Priority Date: 12/22/2010
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Alderete, Juan M. Jr., Monirabbasi, Salman
• Primary Examiner(s): BERDICHEVSKY, AARTI
• Application Number:
  US14/179,772
• Publication Number:
  US 20140163522A1
• Time in Patent Office: 1,083 Days
• US Class Current: 1/1
• CPC Class Codes: A61M 2005/14208 with a programmable infusion control system, characterised by the infusion program
• CPC Class Codes: A61M 2005/14506 mechanically driven, e.g. spring or clockwork
• CPC Class Codes: A61M 2005/16863 Occlusion detection
• CPC Class Codes: A61M 2205/14 Detection of the presence or absence of a tube, a connector or a container in an apparatus
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/332 Force measuring means
• CPC Class Codes: A61M 5/1413 Modular systems comprising interconnecting elements
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/1452 pressurised by means of pistons
• 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 5/5086 for indicating if defective, used, tampered with or unsterile

Abstract

A method of seating a fluid reservoir in a housing of a fluid infusion device is presented here. The method is performed prior to establishing an outgoing fluid flow path from the fluid reservoir. The method begins by detecting insertion of the fluid reservoir into the housing of the fluid infusion device. In response to detecting the insertion, the method determines whether the fluid reservoir is in need of depressurization. When the fluid reservoir is in need of depressurization, the drive motor assembly of the fluid infusion device is rewound to depressurize the fluid reservoir. After depressurizing the fluid reservoir, an equalization state for the fluid reservoir is achieved. After achieving the equilibrium state, the drive motor assembly is advanced to obtain an initial seated state for the fluid reservoir.

Claims

1. A method of seating a fluid reservoir in a housing of a fluid infusion device prior to establishing an outgoing fluid flow path from the fluid reservoir, the fluid infusion device comprising a drive motor assembly, an actuation mechanism operatively coupled to the drive motor assembly for actuation of a plunger of the fluid reservoir, and a force sensor operatively coupled to the actuation mechanism, the method comprising:

detecting insertion of the fluid reservoir into the housing, wherein insertion of the fluid reservoir into the housing causes a shaft of the plunger to engage the actuation mechanism;

after detecting insertion of the fluid reservoir, obtaining a first measure of force using the force sensor, wherein the first measure of force is associated with interaction of the shaft with the actuation mechanism;

comparing the first measure of force to a first threshold force value;

when the first measure of force is greater than the first threshold force value, depressurizing the fluid reservoir;

after depressurizing the fluid reservoir, or when the first measure of force is not greater than the first threshold force value, rewinding the drive motor assembly to achieve an equilibrium state for the fluid reservoir; and

after rewinding the drive motor assembly to achieve the equilibrium state, advancing the drive motor assembly to obtain an initial seated state for the fluid reservoir.

2. The method of claim 1, wherein:

the actuation mechanism comprises a gear assembly that is operated by the drive motor assembly; and

the first measure of force is indicative of force imparted to the gear assembly by the shaft.

3. The method of claim 1, wherein depressurizing the fluid reservoir comprises:

(a) rewinding the drive motor assembly by a predetermined amount;

(b) obtaining an updated measure of force using the force sensor, wherein the updated measure of force is associated with interaction of the shaft with the actuation mechanism;

(c) comparing the updated measure of force to the first threshold force value; and

(d) repeating the steps (a), (b), and (c) until the updated measure of force is less than the first threshold force value.

4. The method of claim 3, further comprising generating an alarm when a total amount of rewinding performed while depressurizing the fluid reservoir exceeds a maximum allowable amount.

5. The method of claim 1, wherein rewinding the drive motor assembly to achieve the equilibrium state comprises:

(a) obtaining an initial comparative measure of force using the force sensor, wherein the initial comparative measure of force is associated with interaction of the shaft with the actuation mechanism;

(b) after obtaining the initial comparative measure of force, rewinding the drive motor assembly by a predetermined amount;

(c) after rewinding the drive motor assembly by the predetermined amount, obtaining a subsequent comparative measure of force using the force sensor, wherein the subsequent comparative measure of force is associated with interaction of the shaft with the actuation mechanism;

(d) calculating a difference between the initial comparative measure of force and the subsequent comparative measure of force;

(e) comparing the difference to an equilibrium threshold value; and

(f) repeating the steps (a), (b), (c), (d), and (e) until the difference is less than the equilibrium threshold value, wherein the subsequent comparative measure of force for a previous iteration of the steps (a), (b), (c), (d), and (e) is used as the initial comparative measure of force for a next iteration of the steps (a), (b), (c), (d), and (e).

6. The method of claim 5, further comprising generating an alarm when a total amount of rewinding performed while attempting to achieve the equilibrium state exceeds a maximum allowable amount.

7. The method of claim 1, wherein advancing the drive motor assembly to obtain the initial seated state comprises:

(a) advancing the drive motor assembly forward by a predetermined amount;

(b) after advancing the drive motor assembly forward by the predetermined amount, obtaining and saving a respective measure of force using the force sensor, wherein the respective measure of force is associated with interaction of the shaft with the actuation mechanism; and

(c) repeating the steps (a) and (b) until each of a number (N) of consecutive respective measures of force exceeds a seating threshold force value, wherein N is an integer greater than one.

8. The method of claim 7, further comprising generating an alarm when a total amount of forward advancing performed while attempting to obtain the initial seated state exceeds a maximum allowable amount.

9. The method of claim 1, wherein advancing the drive motor assembly to obtain the initial seated state comprises:

(a) obtaining an initial comparative measure of force using the force sensor, wherein the initial comparative measure of force is associated with interaction of the shaft with the actuation mechanism;

(b) after obtaining the initial comparative measure of force, advancing the drive motor assembly forward by a predetermined amount;

(c) after advancing the drive motor assembly by the predetermined amount, obtaining a subsequent comparative measure of force using the force sensor, wherein the subsequent comparative measure of force is associated with interaction of the shaft with the actuation mechanism;

(d) calculating a difference between the initial comparative measure of force and the subsequent comparative measure of force;

(e) comparing the difference to a seating threshold force value; and

(f) repeating the steps (a), (b), (c), (d), and (e) until the difference exceeds the seating threshold force value for a number (N) of consecutive iterations of the steps (a), (b), (c), (d), and (e), wherein N is an integer greater than one.

10. The method of claim 9, further comprising generating an alarm when a total amount of forward advancing performed while attempting to obtain the initial seated state exceeds a maximum allowable amount.

11. The method of claim 1, further comprising:

after advancing the drive motor assembly to obtain the initial seated state, performing a stabilizing cycle with the drive motor assembly; and

after performing the stabilizing cycle, advancing the drive motor assembly to obtain a subsequent seated state for the fluid reservoir.

12. The method of claim 11, wherein performing the stabilizing cycle comprises:

advancing the drive motor assembly by a first amount; and

thereafter, rewinding the drive motor assembly by a second amount.

13. A method of seating a fluid reservoir in a housing of a fluid infusion device prior to establishing an outgoing fluid flow path from the fluid reservoir, the fluid infusion device comprising a drive motor assembly, an actuation mechanism operatively coupled to the drive motor assembly for actuation of a plunger of the fluid reservoir, and a force sensor operatively coupled to the actuation mechanism, the method comprising:

detecting insertion of the fluid reservoir into the housing, wherein insertion of the fluid reservoir into the housing causes a shaft of the plunger to engage the actuation mechanism;

after detecting insertion of the fluid reservoir, obtaining a first measure of force using the force sensor, wherein the first measure of force is associated with interaction of the shaft with the actuation mechanism;

comparing the first measure of force to a first threshold force value;

when the first measure of force is greater than the first threshold force value, depressurizing the fluid reservoir by rewinding the drive motor assembly by a controlled rewind amount;

after rewinding the drive motor assembly by the controlled rewind amount, obtaining an updated measure of force using the force sensor, wherein the updated measure of force is associated with interaction of the shaft with the actuation mechanism;

comparing the updated measure of force to the first threshold force value;

determining that the fluid reservoir is depressurized if the updated measure of force is less than the first threshold force value;

if the fluid reservoir is determined to be depressurized, rewinding the drive motor assembly to achieve an equilibrium state for the fluid reservoir; and

after rewinding the drive motor assembly to achieve the equilibrium state, advancing the drive motor assembly to obtain an initial seated state for the fluid reservoir.

14. The method of claim 13, wherein:

the actuation mechanism comprises a gear assembly that is operated by the drive motor assembly; and

the first measure of force is indicative of force imparted to the gear assembly by the shaft.

15. The method of claim 13, wherein rewinding the drive motor assembly to achieve the equilibrium state comprises:

(a) obtaining an initial comparative measure of force using the force sensor, wherein the initial comparative measure of force is associated with interaction of the shaft with the actuation mechanism;

(b) after obtaining the initial comparative measure of force, rewinding the drive motor assembly by a predetermined amount;

(c) after rewinding the drive motor assembly by the predetermined amount, obtaining a subsequent comparative measure of force using the force sensor, wherein the subsequent comparative measure of force is associated with interaction of the shaft with the actuation mechanism;

(d) calculating a difference between the initial comparative measure of force and the subsequent comparative measure of force;

(e) comparing the difference to an equilibrium threshold value; and

(f) repeating the steps (a), (b), (c), (d), and (e) until the difference is less than the equilibrium threshold value, wherein the subsequent comparative measure of force for a previous iteration of the steps (a), (b), (c), (d), and (e) is used as the initial comparative measure of force for a next iteration of the steps (a), (b), (c), (d), and (e).

16. The method of claim 15, further comprising generating an alarm when a total amount of rewinding performed while attempting to achieve the equilibrium state exceeds a maximum allowable amount.

17. The method of claim 13, wherein advancing the drive motor assembly to obtain the initial seated state comprises:

(a) advancing the drive motor assembly forward by a predetermined amount;

(b) after advancing the drive motor assembly forward by the predetermined amount, obtaining and saving a respective measure of force using the force sensor, wherein the respective measure of force is associated with interaction of the shaft with the actuation mechanism; and

(c) repeating the steps (a) and (b) until each of a number (N) of consecutive respective measures of force exceeds a seating threshold force value, wherein N is an integer greater than one.

18. The method of claim 17, further comprising generating an alarm when a total amount of forward advancing performed while attempting to obtain the initial seated state exceeds a maximum allowable amount.

19. The method of claim 13, wherein advancing the drive motor assembly to obtain the initial seated state comprises:

(a) obtaining an initial comparative measure of force using the force sensor, wherein the initial comparative measure of force is associated with interaction of the shaft with the actuation mechanism;

(b) after obtaining the initial comparative measure of force, advancing the drive motor assembly forward by a predetermined amount;

(c) after advancing the drive motor assembly by the predetermined amount, obtaining a subsequent comparative measure of force using the force sensor, wherein the subsequent comparative measure of force is associated with interaction of the shaft with the actuation mechanism;

(d) calculating a difference between the initial comparative measure of force and the subsequent comparative measure of force;

(e) comparing the difference to a seating threshold force value; and

(f) repeating the steps (a), (b), (c), (d), and (e) until the difference exceeds the seating threshold force value for a number (N) of consecutive iterations of the steps (a), (b), (c), (d), and (e), wherein N is an integer greater than one.

20. The method of claim 19, further comprising generating an alarm when a total amount of forward advancing performed while attempting to obtain the initial seated state exceeds a maximum allowable amount.