Medical injection system

• US 20020183616A1
• Filed: 04/19/2002
• Published: 12/05/2002
• Est. Priority Date: 05/30/2001
• Status: Active Grant

• Current Assignee: ACIST Medical Systems Incorporated (Bracco SPA)
• Original Assignee: ACIST Medical Systems Incorporated (Bracco SPA)
• Inventors: McPeak, Tom, Szczech, Chris, Toews, Glenn, Duchon, Doug
• Granted Patent: US 7,308,300 B2
• Time in Patent Office: Days
• US Class Current: 600/432
• CPC Class Codes: A61M 2005/3128 Incorporating one-way valves, e.g. pressure-relief or non-return valves
• CPC Class Codes: A61M 5/007 for contrast media
• 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 5/19 having more than one chamber , e.g. including a manifold coupling two parallelly aligned syringes through separate channels to a common discharge assembly surgical glue applicators A61B17/00491
• CPC Class Codes: A61M 5/31513 Piston constructions to improve sealing or sliding
• CPC Class Codes: A61M 5/31515 Connection of piston with piston rod

Abstract

A method of preventing extravasation of contrast agent during a computed tomography injection. An automatic injector device facilitates ease of accomplishing the method. The method includes establishing the absence of extravasation using an absorbable injectate, such as saline, prior to injecting the contrast agent. The device includes a computerized injector head capable of switching between two injectates without physical human intervention. The device is controlled by a remote operating panel located in a control room that is protected from X-ray radiation. The device includes various software driven safety features that prevent the occurrence of unsafe conditions.

Claims

1. A method of injecting a contrast agent into a vessel of a patient comprising:

providing a percutaneous implement defining a lumen and having a distal end;

attempting to position the distal end of the implement in the vessel such that fluid communication is established between the lumen and the vessel;

instructing an automatic injection device to inject a predetermined amount of a first fluid through the lumen such that the fluid exits the distal end;

determining whether fluid communication is established between the lumen and the vessel;

in the event that said determination is negative, pausing the automatic injection device and repeating the steps of attempting to position the distal end, injecting a predetermined amount of a first fluid, and determining whether fluid communication is established until said determination is affirmative;

resuming the operation of the automatic injection device such that the device injects a predetermined amount of a contrast agent into the vessel through the lumen.

2. The method of claim 1 further comprising:

instructing the automatic injection device to inject a predetermined amount of the first fluid into the vessel through the lumen after the step of injecting a predetermined amount of the contrast agent.

3. The method of claim 1 wherein injecting a predetermined amount of a first fluid comprises injecting a predetermined amount of saline.

4. The method of claim 1 wherein determining whether fluid communication is established between the lumen and the vessel comprises feeling an area of the patient proximate the distal end of the implement for the occurrence of extravasation.

5. The method of claim 1 further comprising:

providing an injectate delivery device having;

first and second syringes each having a distal end;

a catheter connector attachable to the implement;

a fluid communication network, fluidly connecting the distal ends of the first and second syringes to the catheter connector, the network including a shuttle valve constructed and arranged to selectively port fluid from one of the first and second syringes to the catheter connector while blocking fluid from the other of the first and second syringes.

6. A method of injecting a contrast agent into a vessel using an automatic injection device comprising:

operably connecting the device to the patient;

programming the device to inject a predetermined amount of contrast agent into a patient;

programming the device to inject a predetermined amount of a flushing fluid into the patient after the contrast agent has been injected.

7. An injectate delivery device comprising:

first and second syringes each having a distal end;

a catheter connector attachable to a percutaneous implement;

a fluid communication network, fluidly connecting the distal ends of the first and second syringes to the catheter connector, the network including a shuttle valve constructed and arranged to selectively port fluid from one of the first and second syringes to the catheter connector while blocking fluid from the other of the first and second syringes.

8. The device of claim 7 further comprising a first supply connector fluidly coupleable to the first syringe.

9. The device of claim 8 wherein the first supply connector is fluidly coupleable to the distal end of the first syringe.

10. The device of claim 8 further comprising a check valve fluidly coupling the first supply connector to the first syringe.

11. The device of claim 10 wherein the check valve further fluidly couples the first syringe to the shuttle valve.

12. The device of claim 10 wherein the check valve is constructed and arranged such that the valve is biased toward a closed position whereby the fluid connection between the first syringe and the first supply connector is blocked and whereby a predetermined negative pressure in said first syringe, relative to the static fluid pressure in the first supply connector, is required to cause the valve to assume an open position, whereby fluid is able to be drawn into the first syringe from a first fluid supply reservoir operably attached to the first fluid supply connector.

13. The device of claim 12 wherein the check valve comprises:

a tubular housing, attachable at one end to the distal end of the first syringe, defining an inner lumen;

a plug contained within the inner lumen, the plug having a diameter smaller than an inner diameter of the lumen such that fluid may pass around the plug;

a narrowed section extending inwardly from another end of the housing to define a narrow passage having an inner diameter smaller than the diameter of the plug, the narrowed section thereby forming an inner shoulder against which the plug may rest and form a seal preventing fluid from flowing from the first syringe to the narrow passage;

a biasing mechanism contained within the inner lumen, biased to hold the plug against the shoulder until the biasing mechanism is overcome by a predetermined negative pressure in the first syringe, relative to the static fluid pressure in the first supply connector, whereby the plug is drawn away from the shoulder, thereby allowing fluid to flow from the supply connector into the first syringe.

14. The device of claim 7 further comprising a second supply connector fluidly coupleable to the second syringe.

15. The device of claim 14 wherein the second supply connector is fluidly coupleable to the distal end of the second syringe.

16. The device of claim 14 further comprising a second check valve fluidly coupling the second supply connector to the second syringe.

17. The device of claim 16 wherein the second check valve further fluidly couples the second syringe to the shuttle valve.

18. The device of claim 16 wherein the check valve is constructed and arranged such that the valve is biased toward a closed position whereby the fluid connection between the second syringe and the second supply connector is blocked and whereby a predetermined negative pressure in said second syringe, relative to the static fluid pressure in the second supply connector, is required to cause the valve to assume an open position, whereby fluid is able to be drawn into the second syringe from a second fluid supply reservoir operably attached to the second fluid supply connector.

19. The device of claim 18 wherein the check valve comprises:

a tubular housing, attachable at one end to the distal end of the second syringe, defining an inner lumen;

a plug contained within the inner lumen, the plug having a diameter smaller than an inner diameter of the lumen such that fluid may pass around the plug;

a narrowed section extending inwardly from another end of the housing to define a narrow passage having an inner diameter smaller than the diameter of the plug, the narrowed section thereby forming an inner shoulder against which the plug may rest and form a seal preventing fluid from flowing from the second syringe to the narrow passage;

a biasing mechanism contained within the inner lumen, biased to hold the plug against the shoulder until the biasing mechanism is overcome by a predetermined negative pressure in the second syringe, relative to the static fluid pressure in the second supply connector, whereby the plug is drawn away from the shoulder, thereby allowing fluid to flow from the supply connector into the second syringe.

20. The device of claim 7 wherein the shuttle valve comprises:

a housing defining an inner chamber and three connection openings, at least two of the connection openings fluidly leading into the inner chamber through passageways, narrower than the inner chamber, and defined by shoulders extending inwardly from the housing;

two plugs, each having a diameter smaller than that of the inner chamber and larger than that of the passageways, the plugs and shoulders constructed and arranged such that the plugs form seals against the respective shoulders when the plugs are pressed thereagainst;

a biasing mechanism contained within the inner chamber and constructed and arranged such that the plugs are forced against their respective shoulders by the biasing mechanism, thereby forming a seal thereagainst, unless one of the plugs is overcome by fluid pressure from one of the syringes, being forced inwardly, away from its respective shoulder, thereby allowing fluid to flow from the pressure-providing syringe, and into the catheter connector.

21. The injectate delivery device of claim 7 further comprising a coupling between said catheter connector and said shuttle valve, useable to disconnect said catheter connector from said shuttle valve.

22. The injectate delivery device of claim 8 further comprising a coupling between said first supply connector and said first syringe, useable to disconnect said first supply connector from said first syringe.

23. The injectate delivery device of claim 11 further comprising a coupling between said check valve and said shuttle valve, useable to disconnect said check valve from said shuttle valve.

24. The injectate delivery device of claim 14 further comprising a coupling between said second supply connector and said second syringe, useable to disconnect said first supply connector from said first syringe.

25. The injectate delivery device of claim 17 further comprising a coupling between said second check valve and said shuttle valve, useable to disconnect said check valve from said shuttle valve.

27. The device of claim 26 wherein said plunger comprises a magnetic coupler that is magnetically coupleable to the plunger rod.

28. The device of claim 27 wherein said magnetic coupler comprises a magnet.

29. The device of claim 28 wherein said magnet comprises a permanent magnet.

30. The device of claim 28 wherein said magnet comprises a rare earth magnet.

31. The device of claim 27 wherein said magnetic coupler comprises a stack of permanent magnets.

32. The device of claim 27 wherein said magnetic coupler comprises a ferrous material.

33. The device of claim 26 wherein said plunger comprises a radial lip of elastic material extending toward said distal end and constructed and arranged such that as fluid pressure increases in said inner chamber, said fluid pressure forces said lip into fluid tight contact with said inner wall.

34. The device of claim 33 wherein said plunger further comprises a second radial lip of elastic material extending toward said open end and constructed and arranged such that as a negative pressure is created in said inner chamber, relative to ambient pressure, a differential pressure across said second radial lip forces said second radial lip into fluid tight contact with said inner wall.

36. The method of ensuring safe operation of claim 35, wherein the step of sending a shut down signal if the timer has not been reset within a predetermined interval comprises stopping a motor of the automatic injector system which is operably connected to a syringe plunger.

38. The computer program of claim 37 wherein the code segment that sends a shutdown signal if the timer has not been reset within a predetermined interval comprises a code segment that sends a shutdown signal that stops a motor of the automatic injector system which is operably connected to a syringe plunger.

39. The computer program of claim 37 wherein one of the predetermined tasks comprises a code segment that sends a plurality of intermittent pings over a communications link between a first microprocessor and a second microprocessor of the injector system, each ping signifying that said microprocessor is operating normally and in synchronicity with the other microprocessor.

40. The computer program of claim 37 wherein each of said pings are encoded according to a schedule such that said pings change codes and said microprocessors can read said pings only if they are in concert according to said schedule.

26. An injectate delivery device, attachable to an automatic injector device, comprising:

a first syringe and a second syringe, each syringe defining an inner chamber and having an open end and a distal end opposite the open end;

a plunger slideably disposed within the inner chamber of each syringe between the open end and the distal end, the plungers constructed and arranged such that they may be acted upon by a plunger rod of the automatic injection device;

a branched check valve fluidly connected to the distal end of each syringe, each branched valve having a normally blocked port connectable to a fluid supply and a normally open port fluidly connected to a cross tube;

a shuttle valve having three openings, two of said openings fluidly connected to the two cross tubes, the other of said three openings connected to a tube leading to a catheter tube

whereby said check valves and said shuttle valve are constructed and arranged such that pressures created in one of the check valves, during an injection or fill procedure, are not felt within the other of the check valves.

35. A method of ensuring safe operation of an automatic injector system comprising:

monitoring signals from a plurality of predetermined tasks;

verifying that each of the plurality of predetermined tasks has generated one of the signals;

resetting a timer if all of the plurality of signals are “

all normal”

signals; and

,

generating a shut down signal if the watchdog timer has not been reset within a predetermined interval.

37. A computer program for ensuring safe operation of an automatic injector system, the program comprising:

a code segment that monitors a plurality of signals from a plurality of predetermined tasks;

a code segment that verifies that each of the plurality of predetermined tasks has generated one of the plurality of signals;

a code segment that resets a timer if all of the plurality of signals are “

all normal”

signals; and

,

a code segment that sends a shutdown signal if the timer has not been reset within a predetermined interval.

41. An automatic injector control tool implemented on a computer, the tool comprising:

a monitoring unit useable to monitor a plurality of signals from a plurality of predetermined tasks; and

,

a timing unit useable to turn off an automatic injector system after a predetermined period of time;

wherein after the monitoring unit verifies that each of the plurality of predetermined tasks has generated one of the plurality of signals, the monitoring unit resets the timing unit.

42. The automatic injector control tool of claim 41 wherein said monitoring unit comprises a code segment.

43. The automatic injector control tool of claim 41 wherein said timing unit comprises a code segment.

44. A method of controlling a flow rate created by a plunger being forced through a syringe by a motor, comprising:

comparing data representative of actual plunger speed to a predetermined speed setting; and

,

comparing data representative of actual motor load to a predetermined motor load limit;

maintaining said actual plunger speed within a predetermined range of said predetermined speed setting while said actual motor load is less than said predetermined motor load limit;

reducing said actual plunger speed once said actual motor load is equal to or greater than said predetermined motor load limit such that said actual motor load does not exceed said predetermined motor load limit by more than a predetermined amount.

48. The mechanism of claim 47 further comprising a release pin slideably attached to said docking plate, and arranged such that when said pin is depressed, said pin acts against said linkages such that said linkages are folded, pulling said upper portions together.

49. The mechanism of claim 48 further comprising a biasing mechanism, operably attached to said pin, such that said biasing mechanism biases said pin away from said linkages.

45. A method of controlling an automatic injector system comprising:

receiving a plurality of readings from sensors monitoring various operating parameters of the automatic injector system;

comparing said readings to preselected safety limits corresponding to said operating parameters;

monitoring a timer, operably connected to a computer program operating the automatic injector system, to ensure said timer has not elapsed; and

,

tripping a relay, thereby disabling power to a motor of said automatic injector system, in the event that either;

one of said predetermined parameters exceeds its corresponding preselected safety limits by a predetermined amount;

or,

said timer elapses.

46. A control circuit, useable to control an automatic injector system, comprising:

a motor shutdown logic circuit;

a plurality of comparators, each having a first input line, a second input line, and an output line;

wherein;

each of said first input lines is connected to a different sensor measuring a selected operating parameter of the automatic injector system and carries voltages representative of said operating parameter;

each of said second input lines receives voltages corresponding to data representative of a predetermined limit on said selected operating parameter; and

,

each of said output lines is connected to said motor shutdown logic circuit and sends a voltage signal thereto, generated by the corresponding comparator, whenever the voltage carried by the first input line differs from the voltage carried by the second input line by a predetermined amount;

a timer, operably connected to the motor shutdown logic circuit, which sends a signal thereto whenever it achieves a predetermined elapsed time; and

,

a relay, operably connected to said motor shutdown logic circuit, and constructed and arranged to electrically connect a motor of the automatic injector system with a power supply;

whereby said motor shutdown logic circuit trips said relay whenever it receives any of said signals, thereby causing said relay to break the electrical connection between the motor and the power supply.

47. A mechanism useable to attach a flanged syringe to a docking plate of an automatic injector device comprising:

a pair of engagement members pivotally attached to the docking plate and spaced apart from the docking plate such that the flange of the syringe may be accepted between the engagement members and the docking plate; and

,

linkages pivotally attached to upper portions of said engagement members and constructed and arranged to pull said upper portions together when said linkages are folded together;

whereby said engagement members include lower portions, opposite said upper portions, said lower portions shaped to secure the syringe to the docking plate when said linkages are in an unfolded position; and

,

whereby said lower portions are pivoted away from each other when said upper portions are pulled together, thereby allowing the syringe to be removed.

50. A docking plate, useable to attach a flanged syringe to an automatic injector device, the docking plate comprising:

a slot, having an open end, sized to slidingly receive the flange of the syringe;

an opening defined by said plate, opposite said open end, through which a linear actuator of the injector device may pass to act on a plunger of the syringe.

51. The docking plate of claim 50, further comprising a locking mechanism constructed and arranged to hold the flanged syringe within the slot.

52. The docking plate of claim 51 wherein said locking mechanism comprises a spring-loaded catch, arranged to allow the flange to pass over the catch when the syringe is being inserted into the slot.

53. An automatic injector device, comprising:

an injector head in a patient room, the injector head including;

a linear actuator assembly having a motor operably connected to a plunger rod;

a quadrature encoder operably connected to the motor to monitor motor movement;

a first microprocessor operably connected to the motor and having memory;

control software stored in the memory of the first microprocessor;

a plurality of syringes removably attached to the injector head, at least one of which is aligned to receive the plunger rod;

a fluid communications network fluidly connecting the syringes to a patient and including a shuttle valve constructed and arranged to direct fluid from at least one of the plurality of syringes to the patient;

a remote control panel located in a control room that is separated from the patient room;

the remote control panel including;

a second microprocessor having memory;

control software stored in the memory of the second microprocessor;

a communications link providing electronic communication between the first microprocessor and the second microprocessor.

54. The device of claim 53 wherein the injector head further includes a linear position sensor operably connected to the plunger rod, capable of detecting the absolute position of the plunger rod.

55. The device of claim 53 wherein the memory of the first and second microprocessors, and the software stored thereon, comprises modular memory cards, removably attachable to said first and second microprocessors.

56. The device of claim 53 wherein said first and second processors conduct systems checks over said communications link to ensure both microprocessor are operating normally.