Liquid infusion apparatus

• US 20060173412A1
• Filed: 11/10/2005
• Published: 08/03/2006
• Est. Priority Date: 06/17/2002
• Status: Active Grant

• Current Assignee: Iradimed Corporation
• Original Assignee: Iradimed Corporation
• Inventors: Susi, Roger E.
• Granted Patent: US 7,553,295 B2
• Time in Patent Office: Days
• US Class Current: 604/123
• 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 39/26 Valves closing automatically on disconnecting the line and opening on reconnection thereof check valves A61M39/24
• CPC Class Codes: A61M 5/1413 Modular systems comprising interconnecting elements
• CPC Class Codes: A61M 5/142 Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/14228 with linear peristaltic action, i.e. comprising at least three pressurising members or a helical member
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: F04B 43/082 the tubular flexible member being pressed against a wall by a number of elements, each having an alternating movement in a direction perpendicular to the axes of the tubular member and each having its own driving mechanism

Abstract

Liquid infusion apparatus includes non-magnetic materials in a pumping structure and ultrasonic drive motor therefor, and in a controller that supplies drive signals to the motor to facilitate convenient operation in intense magnetic fields without distorting the magnetic fields and without radiating objectionable radio-frequency interference. A non-MRI-compatible liquid infusion apparatus is temporarily replaced with MRI-compatible, non-magnetic liquid infusion apparatus without disconnecting a patient from an installed intravenous infusion set to continue infusing liquid within the MRI environment. The pumping apparatus operates on a segment of a liquid conduit that is mounted in tension between a linear peristaltic pump and platen, with associated safety interlocks to assure proper operation of infusing liquid into a patient compatibly with conditions in an MRI environment. Drive circuitry generates low-harmonic signals for operating the ultrasonic motor at variable speeds to compensate for flow rate discontinuities through the peristaltic pumping cycles.

Claims

1. Liquid infusion apparatus comprising

a liquid conduit including a proximal segment, a distal segment and an intermediate segment therebetween, the intermediate segment including a flexible elastic tubular member of selected cross-sectional dimensions;

a fluid connector in fluid communication with the proximal and intermediate segments; and

a flow valve in fluid communication with the intermediate and distal segments, and including a shuttle member slidably disposed within a housing about the intermediate segment for lateral movement relative to an elongated axis of the intermediate segment to operate in a first configuration impeding fluid flow through the intermediate segment, and in a second configuration for which fluid flow through the intermediate segment is unimpeded, the shuttle member including a resilient grasper for selectively engaging and disengaging a mating actuator resiliently received by the grasper.

2. Liquid infusion apparatus according to claim 1 in which the fluid connector includes a laterally-extending portion relative to the elongated axis of the intermediate segment for supporting the fluid connector and intermediate segment in tension relative to the housing of the flow valve.

3. Liquid infusion apparatus according to claim 1 in which the resilient grasper is disposed to selectively engage an actuator in alignment with the lateral movement of the shuttle member to operate the shuttle member selectively in the first and second configurations.

4. Liquid infusion apparatus according to claim 1 in which the intermediate segment is formed as a tubular member having flexible, elastic wall of a material selected from the group consisting of latex, silicone rubber and flexible, elastic, biocompatible polymers.

5. Liquid infusion apparatus according to claim 3 in which the shuttle member includes an elongated aperture therethrough that tapers in a direction aligned with slidable movement thereof from narrowest cross-sectional dimension to constrict the intermediate segment passing therethrough in the first configuration, to largest cross-sectional dimension unrestrictive of the intermediate segment passing therethrough in a second configuration.

6. Liquid infusion apparatus according to claim 3 in which the shuttle member comprises resilient material forming the grasper that includes a pair of spaced, opposed jaws spanning a recess therebetween for engaging the actuator within the recess between the pair of jaws to transfer sufficient lateral force from the actuator to the shuttle member for sliding actuation thereof from the second configuration to the first configuration.

7. Apparatus for operation with liquid infusion apparatus according to claim 1 including first and second separable components disposed to receive the intermediate segment of the liquid conduit positioned therebetween along the length thereof, the first component including a peristaltic pumping mechanism and the second component including a platen operatively aligned with the pumping mechanism for engaging the intermediate segment therebetween along a portion of the length thereof in a closed configuration of the first and second components.

8. Apparatus according to claim 7 in which the first component includes a housing supporting the peristaltic pumping mechanism therein, and supporting the second component for hinged movement between the closed configuration and an open configuration for exposing an access region of the housing.

9. Apparatus according to claim 8 including first and second receptacles within the access region of the housing disposed in substantial alignment therein with, and spaced at opposite ends of, the peristaltic pumping mechanism for receiving in the first receptacle the fluid connector of a liquid conduit and for receiving the flow valve of a liquid conduit in the second receptacle.

10. Apparatus according to claim 9 in which the spacing apart of the first and second receptacles retains the intermediate segment of a liquid conduit in tension and in alignment with the peristaltic pumping mechanism along a portion of the length of the intermediate segment.

11. Apparatus according to claim 7 in which the second component supports an actuator in alignment with the shuttle member of a flow valve for actuating the shuttle member to the second configuration thereof in response to the closed configuration of the first and second components, and for actuating the shuttle member to the first configuration in response to an open configuration of the first and second components.

12. Apparatus according to claim 7 in which the peristaltic pumping mechanism and platen substantially align along a portion of the intermediate segment of a liquid conduit in the closed configuration of the first and second components;

at least one pressure sensor disposed within the first component in alignment with the intermediate segment of a liquid conduit received in the first component and spaced away from the peristaltic pumping mechanism therein; and

an anvil carried by the second component for operatively engaging the intermediate segments in alignment with the at least one pressure sensor in the closed configuration of the first and second components to sense pressure in the intermediate segment.

13. Apparatus according to claim 7 in which the first component includes a housing containing the peristaltic pumping mechanism and an actuator therefor including a controller operable by computer and programs therefor stored in a memory within the housing.

14. Apparatus according to claim 13 in which the housing and peristaltic pumping mechanism and actuator therefor and computer and memory contained in the housing are formed of non-magnetic material;

and

the housing is formed of non-magnetic, electrically-conductive material for inhibiting radiation of radio frequency interference therefrom.

15. Apparatus according to claim 14 in which the housing comprises a forward segment including the first and second separable components, and a rearward segment;

and

a resilient gasket of electrically conductive material disposed intermediate the forward and rearward segments of the housing.

16. Apparatus according to claim 14 in which the peristaltic pumping mechanism and actuator therefor are disposed in one portion of the housing, and the computer and memory are disposed in another portion of the housing.

17. A method for infusing liquid into a patient using a linear peristaltic pump and platen positionable about a liquid conduit including a tubular segment of flexible elastic material to transfer liquid from a source to the patient, the method comprising:

linearly positioning the tubular segment for engagement with the peristaltic pump;

occluding liquid flow through the tubular segment in response to absence of operational engagement of the platen and tubular segment with the peristaltic pump;

positioning the platen in operative engagement against the tubular segment in alignment with the peristaltic pump; and

disabling occlusion of liquid flow through the tubular segment in response to operational engagement thereof with the platen to enable peristaltic pumping of liquid through the tubular segment.

18. The method according to claim 17 in which occluding liquid flow includes constricting the tubular segment in absence of engagement thereof with the platen;

and

disabling occlusion includes releasing constriction of the tubular segment during operative engagement of the platen with the tubular segment to enable peristaltic pumping of liquid through the tubular segment.

19. The method according to claim 17 including sensing pressure in the tubular segment at a location upstream of the peristaltic pump in response to the platen operatively engaging the tubular segment for selectively controlling the peristaltic pumping.

20. The method according to claim 17 including sensing pressure in the tubular segment at a location downstream of the peristaltic pump in response to the platen operatively engaging the tubular segment for selectively controlling the peristaltic pumping.

21. The method according to claim 17 including sensing flow of bubbles in the liquid conduit at a location therealong downstream of the peristaltic pump to selectively alter the peristaltic pumping.

22. The method according to claim 17 including re-occluding liquid flow through the tubular segment in response to disengagement of the platen from the tubular segment.

23. Apparatus for operation with a liquid conduit including a flow controller, the apparatus comprising:

a housing supporting linear peristaltic pumping apparatus therein;

an access door supported on the housing for movement between open and closed configurations and supporting therein an actuator disposed to operate the flow controller of a liquid conduit;

a platen supported on the access door in alignment with the peristaltic pumping apparatus for operatively engaging a liquid conduit therebetween in the closed configuration of the access door; and

mounts disposed in spaced relationship on the housing for supporting a liquid conduit in tension between the mounts in alignment with the peristaltic pumping apparatus and platen and with the flow controller of the liquid conduit aligned with the actuator for selectively precluding liquid flow through the liquid conduit in the open configuration of the access door, and for enabling liquid flow through the liquid conduit in the closed configuration of the access door.

24. Apparatus according to claim 23 in which the flow controller of a liquid conduit includes a valve member, the apparatus in which one of the mounts includes a receptacle for receiving therein the valve member of a liquid conduit.

25. Apparatus according to claim 24 in which the actuator is disposed on the access door in alignment with a resilient grasper associated with a valve member of a liquid conduit for selectively engaging the valve member and actuator to disable liquid flow through the liquid conduit in response to the access door in open configuration, and for actuating the valve member to enable liquid flow through the liquid conduit in response to the access door in closed configuration.

26. Apparatus according to claim 23 including a pressure sensor disposed in the housing in alignment with a liquid conduit supported therein to sense liquid pressure within the liquid conduit.

27. Apparatus according to claim 26 including a platen carried on the access door for positioning a liquid conduit in contact with the pressure sensor in closed configuration of the access door.

28. Apparatus according to claim 23 including a pump driver coupled to the peristaltic pumping apparatus and a controller connected to operate the pump driver and disposed within the housing.

29. Apparatus according to claim 28 in which the housing and access door are formed of non-magnetic, electrically-conductive material for shielding radio-frequency interference relative to the pump driver and controller therefor.

30. Apparatus according to claim 28 in which the housing includes a forward segment supporting the access door, and a rearward segment, a resilient gasket of electrically conductive material disposed intermediate the forward and rearword segments of the housing.

31. Drive circuitry for an ultrasonic motor, comprising:

an oscillator for generating an output at frequency representative of an applied voltage;

a circuit connected to receive the output from the oscillator for producing recurring output pulses at spaced intervals on a plurality of output terminals;

a pair of air-core transformers, each having a secondary winding for connection to the ultrasonic motor, and having a pair of primary windings for conducting current therethrough in alternating relationship in response to output pulses from separate ones of pairs of the plurality of output terminals.

32. Drive circuitry according to claim 31 in which the circuit produces recurring pulses at substantially equal successive delays sequentially on four output terminals;

and

conduction of current in each of the pair of primary windings on one of the pair of transformers in controlled in response to output pulses appearing on first and third of the four output terminals, and conduction of current in each of the pair of primary windings on another of the pair of transformers is controlled in response to output pulses appearing on second and fourth of the four output terminals for applying drive signals to the ultrasonic motor of substantially sinusoidal wave forms.

33. Drive circuitry according to claim 32 for an ultrasonic motor having capacitive component in the characteristic input impedance, and in which inductance of a transformer and capacitive component of the characteristic input impedance of the motor coact at ultrasonic operating frequencies for applying to the motor a pair of phase-displaced drive signals of substantially sinusoidal wave forms.

34. Drive circuitry according to claim 31 including a charging circuit connected to receive a control signal applied to the oscillator for selectively controlling change of frequency thereof during a charging interval of the charging circuit.

35. Drive circuitry according to claim 31 in which the ultrasonic motor produces an electrical feedback signal representative of the drive signals applied to the motor, the drive circuitry including a feedback circuit for forming a DC voltage level from the electrical feedback signal representative of the drive signals applied to the motor for application to the oscillator to control the operating frequency thereof.

36. Drive circuitry according to claim 32 including switching elements connected to each of the primary windings of each of the transformers for controlling conduction of current therethrough in response to control signals applied thereto;

the switching elements connected to a pair of primary windings on one transformer being connected to receive as control signals, respectively, output pulses appearing on first and third of the four output terminals; and

the switching elements connected to a pair of primary winding on another of the transformers being connected to receive as control signals, respectively, output pulses appearing on second and fourth of the four output terminals.

37. Liquid pumping apparatus including a peristaltic pump operated by an ultrasonic motor coupled thereto, and including a controller for applying drive signals to the motor to modulate the operating speed of the motor during a pumping cycle to substantially linearize the volumetric flow of liquid through the pump per increment of the pumping cycle.

38. A method of altering the liquid flow characteristics of a peristaltic pumping apparatus operated by ultra sonic motor, over a pumping cycle thereof including altering the operating speed thereof during a pumping cycle to substantially linearize volumetric flow of liquid through the pumping apparatus per unit increment of the pumping cycle.