Injection System with Capacitive Sensing

• US 20140142537A1
• Filed: 06/26/2012
• Published: 05/22/2014
• Est. Priority Date: 07/18/2011
• Status: Active Grant

• Current Assignee: Liebel-Flarsheim Company (Mallinckrodt plc)
• Original Assignee: Mallinckrodt LLC (Mallinckrodt plc)
• Inventors: Gibson, Chad M., Neer, Charles S.
• Granted Patent: US 9,849,237 B2
• Time in Patent Office: Days
• US Class Current: 604/500
• CPC Class Codes: A61M 2005/14553 comprising a pressure jacket
• CPC Class Codes: A61M 2205/3317 Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/3389 Continuous level detection A61M2205/3393 takes precedence
• CPC Class Codes: A61M 5/14546 Front-loading type injectors
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/16809 by repeated filling and emptying of an intermediate volume pressure infusion using positive displacement pumps A61M5/142
• 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

Abstract

A powerhead (50) of a power injector is disclosed that includes a syringe housing (110) that contains a capacitive fluid detector (112). The capacitive fluid detector (112) may be operable to detect fluid within a syringe (116) installed on the syringe housing (110). The output of the capacitive fluid detector (112) may be used to estimate the volume of fluid within the syringe (116). The capacitive fluid detector (112) may include a plurality of discrete capacitors (118a-118h) arranged serially along a longitudinal axis (120) of the syringe (116). Each of the plurality of capacitors (118a-118h) may be operable to produce an electric field extending into the syringe (116). Each of the plurality of capacitors (118a-118h) may be formed on a printed circuit board (130).

Claims

1-3. -3. (canceled)

4. An injection system comprising:

an injection device comprising a syringe housing;

a syringe mounted to said injection device, wherein said injection device is operable to discharge fluid from said syringe, wherein said syringe comprises a syringe barrel, wherein said syringe barrel has a syringe barrel length along a syringe barrel longitudinal axis, wherein said syringe housing extends along said syringe barrel;

a capacitive fluid detector disposed along said syringe barrel and enclosed within said syringe housing such that said syringe housing is disposed between said capacitive fluid detector and said syringe, wherein said capacitive fluid detector comprises a plurality of capacitors, wherein said plurality of capacitors are arranged serially along said syringe barrel length, wherein each of said plurality of capacitors is disposed at a different position along said syringe barrel longitudinal axis; and

a syringe barrel zone coextensive with said syringe barrel, wherein said syringe barrel zone comprises a syringe barrel zone length coinciding with said syringe barrel length;

wherein said syringe barrel zone comprises a syringe barrel zone longitudinal axis coinciding with said syringe barrel longitudinal axis.

6. The injection system of claim 4, wherein said plurality of capacitors arranged serially along said syringe barrel zone length comprises at least eight individual capacitors.

7. The injection system of claim 4, wherein each of said plurality of capacitors comprises a pair of electrodes, wherein each electrode of each pair of electrodes is arranged such that a vector perpendicular to and intersecting said electrode does not intersect any other electrode.

8. The injection system of claim 7, wherein each of said pair of electrodes comprises two substantially coplanar electrodes.

9. The injection system of claim 4, wherein each of said plurality of capacitors is interconnected to a integrated circuit, wherein for each of said plurality of capacitors, said integrated circuit is operable to produce a bimodal output, wherein a first mode of said bimodal output is in response to a presence of fluid and a second mode of said bimodal output is in response to a lack of fluid.

10. The injection system of claim 4, wherein each of said plurality of capacitors is operable to produce an analog output that varies in response to an amount of fluid within an electric field of said capacitor.

11. The injection system of claim 4, further comprising fluid level determination logic operable to determine a level of fluid within said syringe barrel zone at least partially based on outputs from said plurality of capacitors.

17. The injection system of claim 4, further comprising user input determination logic operable to determine a user input at least partially based on output from said capacitive fluid detector.

18. The injection system of claim 4, further comprising a capacitive user input detector, wherein an electric field of said capacitive user input detector penetrates said syringe barrel zone within a first region that extends along said syringe barrel zone.

19. The injection system of claim 18, wherein an electric field of said capacitive user input detector penetrates said syringe barrel zone within a second region that extends along said syringe barrel zone, wherein said second region is on an opposite side of said syringe barrel zone than said first region.

20. The injection system of claim 18, further comprising user input determination logic operable to determine a user input at least partially based on output from said capacitive user input detector.

21. The injection system of claim 4, wherein said injection system is operable to detect the presence of a finger of a user adjacent to said syringe barrel zone.

22. The injection system of claim 4, wherein said injection system is operable to detect the movement of a finger of a user adjacent to said syringe barrel zone.

5. (canceled)

12-16. -16. (canceled)

23. A method of operating an injection system, said method comprising:

installing a syringe onto an injection device;

contacting a plunger of said syringe with a ram of said injection device;

moving said ram of said injection device after said installing step and while said ram is in contact with said plunger, wherein said moving step results in a corresponding movement of said plunger;

capacitively sensing fluid within a syringe barrel of said syringe at a plurality of times during said moving step; and

estimating a volume of fluid within said syringe at each of said plurality of times, wherein said estimating step is at least partially based on said capacitively sensing step.

24. The method of claim 23, wherein said moving step comprises retracting said plunger.

25. The method of claim 23, wherein said method further comprises:

drawing fluid into said syringe during said moving step;

for each one of said plurality of times, verifying that said estimated volume of fluid corresponds to a volume of said syringe between a nozzle of said syringe and said plunger;

advancing said plunger to inject fluid into a patient.

26. The method of claim 23, wherein said ram is disposed in a unique location at each of said plurality of times.

27. The method of claim 23, wherein said capacitively sensing and estimating steps are performed continuously during said moving step.

36. The method of claim 23, wherein said method further comprises:

capacitively sensing at least one finger of a user proximate to said syringe barrel of said syringe; and

interpreting, by said injection system, said capacitive sensing as a user input to said injection system.

37. The method of claim 36, wherein said capacitively sensing comprises capacitively sensing two fingers of a user moving along opposite sides of said syringe barrel, wherein said interpreting comprises interpreting said capacitive sensing as an input command to purge said syringe barrel.

28. (canceled)

29. (canceled)

30. A method of operating an injection system, said method comprising:

installing a syringe onto an injection device, wherein said syringe contains fluid for execution of said installing step; and

sensing the presence of said fluid within said installed syringe with a first portion of a plurality of capacitive sensors;

estimating a total volume of said fluid within said installed syringe using said sensing the presence step;

providing a separate input volume to said injection system; and

verifying that said estimated total volume from said estimating step corresponds to said input total volume from said providing step, wherein said verifying step is performed prior to injecting any said fluid from said installed syringe into a patient using said injection device.

31. The method of claim 30, further comprising:

sensing an absence of fluid within said installed syringe with a second portion of said plurality of capacitive sensors.

32. The method of claim 30, wherein said estimating step comprises calculating a percentage fill of said syringe based on a number of capacitive sensors in said first portion.

33. The method of claim 30, wherein said estimating step comprises looking up, in a look-up table, said estimated total volume of fluid, wherein in said lookup table said estimated total volume of fluid corresponds to a number of said plurality of capacitive sensors in said first portion.

34. The method of claim 30, wherein said estimating step comprises dividing a number of said plurality of capacitive sensors in said first portion by a total number of said plurality of capacitive sensors.

38-43. -43. (canceled)