Fluid delivery system and flow control therefor

• US 20060142692A1
• Filed: 01/17/2006
• Published: 06/29/2006
• Est. Priority Date: 06/21/2002
• Status: Active Grant

• Current Assignee: Baxter International Inc.
• Original Assignee: Baxter International Inc.
• Inventors: Yardimci, Atif, Jacobson, James D., Slepicka, James S., Garchow, Stephen R., Bui, Tuan
• Granted Patent: US 7,879,025 B2
• Time in Patent Office: Days
• US Class Current: 604/67
• CPC Class Codes: A61M 2205/0244 Micromachined materials, e.g. made from silicon wafers, microelectromechanical systems [MEMS] or comprising nanotechnology
• CPC Class Codes: A61M 2205/0294 Piezoelectric materials
• CPC Class Codes: A61M 5/14236 Screw, impeller or centrifugal type pumps
• CPC Class Codes: A61M 5/16886 for measuring fluid flow rate, i.e. flowmeters
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: G05D 7/0676 by action on flow sources G05D7/0688, G05D7/0694 take precedence

Abstract

A fluid delivery system having a closed-loop control process for delivering a medical fluid to a patient. A fluid infusion system includes a pump for delivering a fluid to a patient via an administration tube. A flow sensor associated with the administration tube provides an indication of the actual flow rate of fluid in the administration tube. Such a flow sensor may comprise a positive displacement flow sensor constructed using micro-fabrication and/or micro-molding techniques. A reader reads the actual flow rate signal and provides an indication to a controller for controlling the pump. The flow rate information can also be used for providing status information, such as the existence of a blockage in the fluid delivery system.

Claims

1. (canceled)

2. A system as set forth in claim 1 wherein the flow sensor comprises a passive device having no electrical connections thereto.

3. A system as set forth in claim 1 wherein the delivery channel comprises an administration tube and the flow sensor is sized and shaped for being positioned in fluid communication with the fluid within the delivery channel.

4. A system as set forth in claim 3 wherein the flow sensor comprises a MEMS device.

5. A system as set forth in claim 3 wherein the flow sensor comprises an assembly of micro-molded components.

7. A system as set forth in claim 3 further comprising a reader associated with the flow sensor for receiving the flow rate signal and providing a flow control signal indicative of the flow rate signal, said controller receiving the flow control signal and adjusting the output rate of the pump in response thereto.

8. A system as set forth in claim 7 wherein the flow sensor comprises a rotatable impeller for rotating in response to the flow of the fluid in the administration tube and the flow rate signal comprises an optical indication generated by a rotation of the rotatable impeller, and wherein the reader comprises an optical reader responsive to the optical indication for providing the flow control signal.

9. A system as set forth in claim 8 wherein:

the optical reader illuminates the flow sensor causing a reflection from the rotatable impeller; and

the optical indication generated by the rotation of the rotatable impeller comprises a variation in an intensity of the reflection from the rotation of the rotatable impeller.

10. A system as set forth in claim 7 wherein:

the flow sensor includes a rotatable impeller for rotating in response to the flow of the fluid in the administration tube; and

the reader comprises a Hall sensor that senses an electrical signal caused by a rotation of the rotatable impeller and provides the flow control signal in response thereto.

11. A system as set forth in claim 7 further comprising:

a communication channel between the reader and the controller, said reader providing a flow control signal indicative of the flow rate signal to the communication channel and said controller receiving the flow control signal via the communication channel and causing adjustments to the output rate of the pump in response thereto.

20. A system as set forth in claim 1 wherein the controller provides a flow rate status signal indicative of a blockage in the delivery channel when the flow rate signal indicates the rate of flow of fluid in the delivery channel is less than a blockage threshold.

22. A system as set forth in claim 20 further comprising a status monitoring device responsive to the flow rate status signal for providing an alarm to a user and a communication channel for transmitting the flow rate status signal from the controller to the status monitoring device.

23. A system as set forth in claim 22 wherein the communication channel comprises a wireless spread spectrum communication channel operating in an unlicensed frequency band.

80. A system as set forth in claim 3 wherein the delivery channel comprises an administration tube and further comprising an administration set constructed and arranged for disposable use, said administration set including the administration tube, the flow sensor, and the pump.

81. A system as set forth in claim 80 wherein the controller comprises a reusable control unit configured to receive the administration set.

6. (canceled)

12. (canceled)

17-19. -19. (canceled)

21. (canceled)

24-58. -58. (canceled)

59. A method of detecting a blockage in a medical fluid delivery system arranged for delivering a medical fluid to a delivery point associated with a patient at a desired flow rate, the method comprising:

operatively connecting a reservoir to a delivery mechanism, said reservoir containing the medical fluid to be delivered to the delivery point;

operatively connecting the delivery mechanism to an administration tube, said administration tube being in fluid communication with the delivery point, said delivery mechanism receiving the medical fluid from the reservoir and supplying the medical fluid to the delivery point via the administration tube at an output flow rate;

sensing the output flow rate of the medical fluid in the administration tube;

determining if the sensed output flow rate is indicative of a blockage in the administration tube; and

providing an alarm signal if it is determined that the sensed output flow rate indicates that the administration tube is blocked.

60. A method as set forth in claim 59 wherein determining if the sensed output flow rate is indicative of a blockage in the administration tube comprises comparing the sensed output flow rate to a blockage threshold such that the alarm signal is provided if the output flow rate is less than the blockage threshold.

61. A method as set forth in claim 60 wherein determining if the sensed output flow is indicative of a blockage in the administration tube comprises averaging the sensed output flow rate of the medical fluid in the administration tube over a time period and comparing said averaged sensed output flow rate to a blockage reference such that the alarm signal is provided if the averaged sensed flow rate is less than the blockage reference.

62. A method as set forth in claim 59 further comprising receiving the alarm signal at a status monitoring device associated with the medical fluid delivery system and providing an indication of the alarm signal at the status monitoring device.

82. A method as set forth in claim 59 wherein the output flow rate of the medical fluid in the administration tube is sensed with a positive displacement flow sensor and wherein the administration tube and flow sensor comprise an administration set constructed and arranged for disposable use.

63-66. -66. (canceled)

68-78. -78. (canceled)

79. A system for delivering a fluid from a reservoir to a delivery point, said system comprising:

a delivery channel between the reservoir and the delivery point through which the fluid is delivered to the delivery point;

a pump associated with the delivery channel for operatively delivering the fluid to the delivery point at an adjustable output rate according to a desired flow rate;

a flow sensor located along the delivery channel for sensing a flow of the fluid in the delivery channel and for generating a flow rate signal indicative of a rate of flow of the fluid in the delivery channel, said flow sensor comprising a positive displacement flow sensor; and

a controller for generating a pump control signal as a function of the flow rate signal to control the pump, said controller causing adjustments to the output rate of the pump in response to the pump control signal whereby the desired flow rate is substantially achieved.

13. A system as set forth in claim 79 wherein the delivery channel comprises an administration tube and the pump comprises an infusion pump located along the administration tube.

14. A system as set forth in claim 13 wherein the infusion pump is a peristaltic pump, a piezoelectric pump or a valve pump.

15. A system as set forth in claim 13 wherein the infusion pump comprises an ambulatory infusion pump.

16. A system as set forth in claim 13 wherein the infusion pump comprises a volumetric infusion pump.

83. An infusion system for delivering fluid from a reservoir to a delivery point associated with a patient, said system comprising:

a disposable administration set comprising;

a delivery channel between the reservoir and the delivery point through which the fluid is delivered to the patient;

a pump located along the delivery channel for operatively delivering the fluid to the delivery point at an adjustable output rate according to a desired flow rate; and

;

a positive displacement flow sensor located along the delivery channel for sensing a flow of the fluid in the delivery channel and for generating a flow rate signal indicative of a rate of flow of the fluid in the delivery channel; and

a reusable control unit configured to receive the disposable administration set comprising a controller for generating a pump control signal as a function of the flow rate signal to control the pump, said controller causing adjustments to the output rate of the pump in response to the pump control signal whereby the desired flow rate is substantially achieved.

84. An infusion system as set forth in claim 83 wherein the control unit provides a flow rate status signal indicative of a blockage in the delivery channel when the flow rate signal indicates the rate of flow of fluid in the delivery channel is less than a blockage threshold.