Drug infusion device with tissue identification using pressure sensing

• US 20050004514A1
• Filed: 04/20/2004
• Published: 01/06/2005
• Est. Priority Date: 04/10/1998
• Status: Active Grant

• Current Assignee: Milestone Scientific Incorporated
• Original Assignee: Milestone Scientific Incorporated
• Inventors: Hochman, Mark N.
• Granted Patent: US 7,449,008 B2
• Time in Patent Office: Days
• US Class Current: 604/67
• CPC Class Codes: A61B 17/3478 Endoscopic needles, e.g. for infusion biopsy needles A61B10/0233; catheters with injection needles A61M25/0067
• CPC Class Codes: A61B 2090/064 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61M 2205/3344 Measuring or controlling pressure at the body treatment site
• 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 5/16854 by monitoring line pressure

Abstract

An automatic injection device includes a drive mechanism and a sensor used to determine an internal characteristic such as a force or internal pressure generated during an injection process. This characteristic is then used as a control parameter by a microprocessor or controller to determine the exit pressure of the fluid expelled by the device. This exit pressure is then used to identify the kind of tissue in which the injection is being introduced.

Claims

1. An apparatus comprising:

a pumping mechanism;

a fluid container coupled to said housing and activated by said pumping mechanism to pump fluid, said fluid exiting at an exit pressure;

a sensor arranged to determine said exit pressure;

a controller receiving exit pressure and generating an output indicative of a patient tissue receiving said fluid based on said exit pressure.

2. The apparatus of claim 1 further pressure sensor sensing a pressure within said pumping mechanism and a calculator receiving said pressure and deriving in response said exit pressure.

3. The apparatus of claim 1 further comprising a memory containing information correlating exit pressures to tissue types, wherein said controller receives said exit pressure compares said exit pressure to said information and generates said output in accordance with said information.

4. An apparatus comprising:

a pumping mechanism;

a fluid container coupled to said housing and activated by said pumping mechanism to pump fluid, said fluid exiting at an exit pressure;

a sensor arranged to enable sensing and identification of specific biological tissue types based on the exit pressures;

a controller receiving said exit pressure and generating an output indicative of the biological tissue based on said exit pressure.

5. The apparatus of claim 4 wherein said pumping mechanism includes a container holding said fluid, a plunger reciprocating within said container and a motor responsive to signals from said controller and driving said plunger.

6. The apparatus of claim 5 wherein said sensor is disposed between said motor and said plunger to sense a force applied to said plunger.

7. The apparatus of claim 5 wherein said pumping mechanism includes a flexible tubing leading said fluid to the biological tissue, and wherein said sensor is coupled to said flexible tubing.

8. The apparatus of claim 7 wherein said tubing expands and contracts radially in response to the fluid pressure and wherein said sensor includes a tubing holder holding at least a portion of said tubing in a preselected position and a force sensor activated by said portion within said holder.

9. The apparatus of claim 8 wherein said holder includes a base with a slot holding the tubing portion, a cover folded over said base and holding said tubing in said trough.

10. The apparatus of claim 9 further comprising a hole passing to said slot with said force sensor being disposed in said hole.

11. The apparatus of claim 9 wherein said holder includes a base, a floating plate resting on said base, and a cover holding said tubing portion with said floating plate.

12. The apparatus of claim 11 with a force sensor sensing a force between the floating plate and said base.

13. The apparatus of claim 7 wherein said sensor includes a size sensor sensing a dimension of said tubing.

14. The apparatus of claim 13 wherein said sensor includes a light source and a light sensor, said light sensor generating an output indicative of the internal pressure within the tubing.

15. The apparatus of claim 4 further comprising a power source providing power to said pumping mechanism, wherein said sensor determines the power provided to the pumping mechanism to determine said exit pressure.

16. The apparatus of claim 4 further comprising a housing and said pumping mechanism includes a cartridge holding said fluid.

17. The apparatus of claim 16 wherein said sensor includes a load sensor disposed between said housing and said cartridge holder.

18. A method of identifying body tissues during the injection comprising:

injecting a fluid into a body tissue through a needle;

determining an exit pressure of said fluid through said needle; and

generating an output indicative of the body tissue based on said exit pressure.

19. The method of claim 18 further comprising providing a pumping mechanism for pumping the fluid through the needle, sensing an internal pressure within said pumping mechanism and calculating said exit pressure from said internal pressure.

20. The method of claim 19 further comprising pushing the needle through several tissues, each tissue having a different density, measuring the exit pressure corresponding to each tissue and generating a corresponding output indicative of the tissues receiving the fluid.