Catheter with Pressure Sensor and Guidance System

• US 20070282211A1
• Filed: 06/04/2007
• Published: 12/06/2007
• Est. Priority Date: 06/05/2006
• Status: Active Grant

• Current Assignee: Physical Logic AG
• Original Assignee: Physical Logic AG
• Inventors: Ofek, Eran, Zipes, Douglas P.
• Granted Patent: US 7,520,858 B2
• Time in Patent Office: Days
• US Class Current: 600/523
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61M 2025/0002 with a pressure sensor at the distal end
• CPC Class Codes: A61M 2025/0166 Sensors, electrodes or the like for guiding the catheter to a target zone, e.g. image guided or magnetically guided
• CPC Class Codes: A61M 25/008 Strength or flexibility characteristics of the catheter tip
• CPC Class Codes: A61M 25/0082 Catheter tip comprising a tool

Abstract

A catheter terminates at a tip that includes an array of pressure sensors. The sensors are responsive to detect and alert the user to variations of pressure that indicate the tip is either encountering an obstruction or constriction of smaller diameter than the catheter, as well as to guide the catheter through the conduit into which it is being inserted.

Claims

1. A catheter comprising:

a) a smooth elongated tube having a tip,

b) a plurality of pressure sensors distributed about the tip for measuring at least one of pressure fluctuations and variations of pressure associated with the orientation of the catheter within a narrow channel comparable to the width of said smooth elongated tube.

2. A catheter according to claim 1 wherein at least one pressure sensor is disposed at the tip of the catheter.

3. A catheter according to claim 1 wherein the tip of the catheter is more compliant than the smooth elongated tube so as to transmit energy to the pressure sensors.

4. A catheter according to claim 1 wherein two or more pressure sensors are disposed at substantially equal radial spacing around the circumference of the tip of the catheter.

5. A catheter according to claim 4 wherein two or more pressure sensors are disposed at substantially equal radial spacing around the circumference of the tip of the catheter.

6. A catheter according to claim 1 and further comprising a plurality of additional sensors disposed distal from the tip of the catheter.

7. A catheter according to claim 6 wherein the additional sensors are pressure sensors.

8. A catheter according to claim 1 wherein at least one pressure sensor is a MEMS sensor.

9. A catheter according to claim 1 wherein at least one pressure sensor is a nano sensor comprising:

a) non-rigid substrate,

b) a non-conductive columnar spacer disposed on said non-rigid substrate,

c) an array of particles bonded to said substrate via said spacer wherein at least one column is connected to each particle,

d) whereby deformation of said non-rigid substrates results in a perturbation to the distribution of the particles in said array to produce a measure change in the aggregate physical property of said array.

10. A catheter according to claim 1 wherein at least one pressure sensor is a nano sensor comprising:

a) a substrate,

b) a polymeric spacer layer disposed on said substrate,

c) an array of particles bonded to the surface of said polymeric spacer,

d) whereby deformation of at least one of said substrate and said polymeric spacer layer results in a perturbation to the distribution of the nano-particles in said array to produce a measurable change in the aggregate physical property of said array.

11. A catheter according to claim 10 wherein the particles are conductive nanoparticles and the property is electrical resistance.

12. A catheter according to claim 1 wherein the pressure sensor is a nano sensor comprising:

a) a substrate,

b) a supporting plate extending upward from said substrate,

c) a beam coupled on at least one end to said supporting plate and extending over said substrate,

d) a strain sensitive conductive coating disposed on at least one surface of said beam that extends over said substrate,

e) a pair of electrodes disposed in electrical contact to said strain sensitive coating to measure a change in resistance there between in response to the deformation of the portion of said beam that extends over said substrate.

f) wherein said strain sensitive coating comprises a 2-dimensional array of substantially mono-disperse conductive nanoparticles mechanically coupled to said beam wherein the nanoparticles in said array separate from each other in response to the deformation of said beam.

13. A catheter according to claim 1 wherein at least one pressure sensor is a nano sensor comprising:

a) a plurality of repeating thin film layers having in a repeating sequence the ordered structure of;

i) a dielectric material,

ii) a first conductive layer,

iii) a dielectric material,

iv) a second conductive layer, wherein when the first and second layers are metals, the work function of the first metal differs from the work function of the second metal, and when the first and second layers are semi-conductors the Fermi level of the first semi-conductor differs from the Fermi level of the second semi-conductor, and

b) a first terminal connecting all the first conductive layers,

c) a second terminal connecting all the second conductive layers, wherein the first and second conductive layers are electrically insolated by the dielectric materials.

14. A catheter according to claim 13 wherein at least one of the first and second conductive layers is a metal and at least one of the dielectric materials is polymeric.

15. A process for inserting a catheter within a narrow channel, the process comprising the steps of:

a) providing a catheter comprising

i) a smooth elongated tube having a tip,

ii) a plurality of pressure sensors distributed about the tip for measuring at least one of pressure fluctuations and variations of pressure associated with the orientation of the catheter within a narrow channel comparable to the width of said smooth elongated tube.

b) introducing the catheter into a bodily conduit of living creature,

c) monitoring at least one of the absolute and differential pressure between the plurality of sensors.

16. A process for inserting a catheter according to claim 15 further comprising the step of selecting a pressure threshold at which one or more the pressure sensors is responsive to transmit an alarm signal to the user that the catheter should not be advanced further within the living creature.

17. A process for inserting a catheter according to claim 15 further comprising the step of transmitting to the user instructions to steer the catheter based on the differential pressure between the plurality of sensors.

18. A process according to claim 15 wherein at least one pressure sensor is disposed at the tip of the catheter.

19. A process according to claim 15 wherein the tip of the catheter is more compliant than the smooth elongated tube so as to transmit energy to the pressure sensors.

20. A process according to claim 15 wherein two or more pressure sensors are disposed at substantially equal radial spacing around the circumference of the tip of the catheter.