FLUID RESERVOIR SEATING PROCEDURE FOR A FLUID INFUSION DEVICE

• US 20120259282A1
• Filed: 06/20/2012
• Published: 10/11/2012
• 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
• Granted Patent: US 8,690,855 B2
• Time in Patent Office: Days
• US Class Current: 604/131
• 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 for the fluid reservoir, the method comprising:

detecting insertion of the fluid reservoir into the housing;

in response to the detecting, determining whether the fluid reservoir is in need of depressurization;

when the fluid reservoir is in need of depressurization, rewinding the drive motor assembly to depressurize the fluid reservoir;

after depressurizing the fluid reservoir, achieving an equilibrium state for the fluid reservoir; and

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

2. The method of claim 1, further comprising:

after advancing the drive motor assembly to obtain the initial seated state, coupling the fluid reservoir to a fluid delivery conduit to deliver fluid from the fluid reservoir to a user.

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

4. The method of claim 3, wherein the subsequent seated state is identical to the initial seated state.

5. The method of claim 3, 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.

6. The method of claim 1, wherein:

rewinding the drive motor assembly to depressurize the fluid reservoir is performed using a first pulse-width modulation duty cycle;

advancing the drive motor assembly to obtain the initial seated condition is performed using a second pulse-width modulation duty cycle; and

the first pulse-width modulation duty cycle is different than the second pulse-width modulation duty cycle.

7. 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.

8. The method of claim 7, 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.

9. The method of claim 7, 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.

10. The method of claim 9, further comprising generating an alarm when a total amount of rewinding performed while depressurizing the fluid reservoir exceeds a maximum allowable amount.

11. The method of claim 7, 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).

12. The method of claim 11, further comprising generating an alarm when a total amount of rewinding performed while attempting to achieve the equilibrium state exceeds a maximum allowable amount.

13. The method of claim 7, 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.

14. The method of claim 13, 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.

15. The method of claim 7, 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.

16. The method of claim 15, 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.

17. The method of claim 7, 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.

18. The method of claim 17, 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.

19. A fluid infusion device comprising:

a housing that receives a sealed fluid reservoir, the fluid reservoir comprising a plunger and a shaft coupled to the plunger;

a drive motor assembly in the housing;

an actuation mechanism in the housing, wherein the actuation mechanism is operatively coupled to the drive motor assembly;

a force sensor in the housing and operatively coupled to the actuation mechanism to obtain measures of force associated with interaction of the shaft with the actuation mechanism; and

at least one processor in the housing and operatively coupled to the drive motor assembly and the force sensor, wherein the at least one processor;

detects insertion of the fluid reservoir into the housing;

thereafter, incrementally rewinds the drive motor assembly to achieve an equilibrium state for the fluid reservoir;

thereafter, advances the drive motor assembly and obtains at least one measure of force using the force sensor until the at least one measure of force indicates that the fluid reservoir has reached an initial seated state;

thereafter, performs a stabilizing cycle with the drive motor assembly to stabilize the fluid reservoir; and

thereafter, advances the drive motor assembly and obtains at least one subsequent measure of force using the force sensor until the at least one subsequent measure of force indicates that the fluid reservoir has reached a subsequent sealed state.

20. The fluid infusion device of claim 19, wherein, after detecting insertion of the sealed fluid reservoir into the housing, the at least one processor:

obtains at least one initial measure of force that indicates that the fluid reservoir is in need of depressurization; and

performs a depressurizing operation by rewinding the drive motor assembly.

21. The fluid infusion device of claim 20, 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.

22. 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 shaft of the fluid reservoir, and a force sensor operatively coupled to the actuation mechanism, the method comprising:

obtaining a first measure of force using the force sensor, wherein the first measure of force is associated with interaction of the plunger shaft with the actuation mechanism;

determining that the first measure of force is greater than a first threshold force value;

in response to the determining, depressurizing the fluid reservoir by rewinding the drive motor assembly by a first rewind amount;

after depressurizing the fluid reservoir, rewinding the drive motor assembly by a second rewind amount to achieve an equilibrium state for the fluid reservoir;

after rewinding the drive motor assembly by the second amount, advancing the drive motor assembly by a first forward amount to obtain an initial seated state for the fluid reservoir;

after obtaining the initial seated state, advancing the drive motor assembly by a second forward amount;

after advancing the drive motor assembly by the second forward amount, rewinding the drive motor assembly by a third rewind amount to stabilize the fluid reservoir;

after rewinding the drive motor assembly by the third rewind amount, advancing the drive motor assembly by a third forward amount to obtain a subsequent seated state for the fluid reservoir.

23. The method of claim 22, further comprising:

after obtaining the subsequent seated state, coupling the housing of the fluid infusion device to a base plate of the fluid infusion device, wherein the coupling establishes a fluid flow path from the fluid reservoir to a fluid delivery path in the base plate.