High Precision Infusion Pumps

• US 20100211003A1
• Filed: 09/17/2008
• Published: 08/19/2010
• Est. Priority Date: 09/17/2007
• Status: Active Grant

• Current Assignee: Vtitan Corporation Private Limited
• Original Assignee: Vtitan Corporation Private Limited
• Inventors: Sundar, Satish, Balakrishnan, Swaminathan, Melnyk, Ivan
• Granted Patent: US 8,147,448 B2
• Time in Patent Office: Days
• US Class Current: 604/67
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• 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 2205/3592 using telemetric means, e.g. radio or optical transmission
• CPC Class Codes: A61M 5/141 with capillaries for restricting fluid flow
• CPC Class Codes: A61M 5/1411 Drip chambers A61M5/162, A61M5/1689, A61M5/40 take precedence
• CPC Class Codes: A61M 5/1454 spring-actuated, e.g. by a clockwork
• 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 5/14586 pressurised by means of a flexible diaphragm
• CPC Class Codes: A61M 5/16813 by controlling the degree of opening of the flow line
• CPC Class Codes: A61M 5/1684 by detecting the amount of infusate remaining, e.g. signalling end of infusion
• CPC Class Codes: A61M 5/16881 Regulating valves on-off valves, e.g. clamps A61M39/28
• CPC Class Codes: A61M 5/1689 Drip counters
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: Y10S 128/12 Pressure infusion
• CPC Class Codes: Y10S 128/13 Infusion monitoring

Abstract

A system architecture for closed loop control of infusion devices is described. The architecture provides means to control the flow from an infusion device as well as in some embodiments the pressure of the delivery. A variety of infusion systems are described that use the closed loop control architecture. In some embodiments the closed loop control may be adapted to current commonly used infusion means such as a gravity feed intravenous system. Other embodiments describe infusion pump system that use biasing or drive mechanisms of springs, elastomers, rotary and linear motors.

Claims

1. An infusion pump for delivering a fluid comprising:

a) a syringe having a plunger, a barrel and an exit,

b) a biasing means to apply force to the plunger thereby causing the plunger to move relative to the barrel,

c) a sensing means to determine the position of the plunger relative to the barrel,

d) a means to restrict flow of the fluid from the exit of the syringe, and,

e) a controller means to control the means to restrict flow based upon feedback from the sensing means.

2. The infusion pump of claim 1 where the biasing means comprises a spring.

3. The infusion pump of claim 1 where the sensing means comprises a plurality of magnets mounted within the plunger along the plunger'"'"'s longitudinal axis and a magnetic sensor attached to the barrel.

4. The infusion pump of claim 1 where the means to restrict flow comprises an actuator that squeezes a compressible tube attached to the exit of the syringe.

5. The infusion pump of claim 2 where the spring is incorporated within the barrel of the syringe.

6. The infusion pump of claim 1 where the biasing means comprises a spring incorporated in the barrel of the syringe, the sensing means comprises a plurality of magnets in the plunger and a magnetic sensor attached to the barrel and the means to restrict flow comprises an actuator that squeezes a compressible tube attached to the exit of the syringe.

7. The infusion pump of claim 1 where the sensing means comprises a ferromagnetic cylinder attached to the plunger and a coil encircling said ferromagnetic cylinder such that movement of the plunger causes a change in the position of the ferromagnetic cylinder within the coil and thereby changes the inductance of the coil.

8. The infusion pump of claim 7 where controllable application of current to the coil controls the rate of movement of the plunger in the barrel.

9. The infusion pump of claim 2 where the sensing means comprises a ferromagnetic cylinder attached to the plunger and a coil encircling said ferromagnetic cylinder such that movement of the plunger causes a change in the position of the ferromagnetic cylinder within the coil and thereby changes the inductance of the coil.

10. The infusion pump of claim 9 where controllable application of current to the coil controls the rate of movement of the plunger in the barrel.

11. An infusion pump for delivering a fluid comprising:

a) a syringe having a plunger, a barrel and an exit,

b) a biasing means to apply force to the plunger thereby causing the plunger to move relative to the barrel thereby creating a pressure within the barrel,

c) a sensing means to determine the position of the plunger relative to the barrel, and,

d) a controller means to control the biasing means based upon feedback from the sensing means

e) said biasing means having a following error said error defined as the difference between a commanded position and an actual position of the biasing means.

12. The infusion pump of claim 11 where the biasing means comprises a rotary motor, a ball screw and a linear guide attached to the plunger such that rotation of the motor moves the plunger relative to the barrel.

13. The infusion pump of claim 12 further comprising a rotary encoder to determine the position of rotational position of the motor.

14. The infusion pump of claim 11 where the means to determine the position of the plunger relative to the barrel comprises a plurality of magnets fixedly mounted relative to the barrel along a longitudinal axis and a magnetic sensor attached to the plunger such that movement of the plunger relative to the barrel moves the magnetic sensor relative to the magnets.

15. The infusion pump of claim 11 where the means to determine the position of the plunger relative to the barrel comprises a linear optical encoder strip fixedly mounted relative to the barrel along a longitudinal axis and an optical sensor attached to the plunger such that movement of the plunger relative to the barrel moves the optical sensor relative to the optical encoder strip.

16. The infusion pump of claim 11 where the biasing means comprises a linear motor attached to the plunger such that motion of the motor moves the plunger relative to the barrel.

17. The infusion pump of claim 11 where the biasing means comprises a linear motor attached to the plunger such that motion of the motor moves the plunger relative to the barrel.

18. The infusion pump of claim 11 where the biasing means comprises a lead screw fixed relative to the barrel and a rotary motor that movably engages the lead screw said rotary motor attached to the plunger such that rotary motion of the motor moves the plunger relative to the barrel.

19. The infusion pump of claim 11 where the following error of the biasing means is used to estimate the pressure in the barrel.