Systems and methods for positioning a catheter

• US 8,971,994 B2
• Filed: 04/08/2013
• Issued: 03/03/2015
• Est. Priority Date: 02/11/2008
• Status: Active Grant

• Current Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Original Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Inventors: Burnside, Eddie K., Messerly, Shayne, Golden, Robert N., Lee, Rand W.
• Primary Examiner(s): Le, Long V.
• Assistant Examiner(s): Negarestan, Farshad
• Application Number:
  US13/858,782
• Publication Number:
  US 20130217999A1
• Time in Patent Office: 694 Days
• Field of Search: 128/899
• US Class Current: 600/424
• CPC Class Codes: A61B 1/00158 using magnetic field
• CPC Class Codes: A61B 5/05 Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves impedance plethysmography A61B5/0295; measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61B 5/6851 Guide wires
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence

Abstract

A method for displaying a position of a medical device, such as a catheter, during insertion thereof into a patient. In one example embodiment, the method includes obtaining a first set of detected position data relating to a location marker, such as a permanent magnet, then determining a possible first position thereof. A first confidence level relating to a match between the first set of detected position data and a first set of predicted position data is assigned. A determination is made whether the first confidence level meets or exceeds a first threshold. If the first confidence level meets or exceeds the first threshold, a determination is then made whether the first position of the location marker is within a first detection zone. If the first position of the location marker is within the first detection zone, the first position of the location marker is displayed.

Claims

1. A method of depicting a position of a medical device that is within a patient, the method comprising:

providing the medical device including a permanent magnet;

inserting the medical device into a blood vessel;

positioning a detector having a first detection zone and a second detection zone such that at least the first detection zone includes a portion of the blood vessel into which the medical device is inserted;

obtaining, via the detector, first measurements of a magnetic field produced by the permanent magnet;

determining a first confidence level regarding a first position of the permanent magnet based on the first measurements;

displaying an initial representative image of the permanent magnet if the first position is within the first detection zone and the confidence level is above a first threshold value;

obtaining, via the detector, second measurements of the magnetic field produced by the permanent magnet;

determining a second confidence level regarding a second position of the permanent magnet based on the second measurements; and

displaying a subsequent representative image of the permanent magnet if the second position is within one or more of the first and second detection zones and the confidence level is above a second threshold value different than the first threshold value.

2. The method according to claim 1, wherein the permanent magnet comprises a plurality of permanent magnetic materials and the providing includes positioning the permanent magnetic materials at a distal portion of the medical device.

3. The method according to claim 1, wherein the medical device is a stylet and the inserting comprises inserting the stylet into a catheter and inserting the catheter into the blood vessel.

4. The method according to claim 1, wherein the second threshold value is lower than the first threshold value.

5. The method according to claim 1, further comprising withholding the initial representative image of the permanent magnet from being displayed if the first position is within the second detection zone and the first confidence level is above the first threshold value.

6. The method according to claim 1, further comprising:

tracking movement of the permanent magnet after having displayed the initial representative image; and

discontinuing to track movement of the permanent magnet prior to displaying the subsequent representative image.

7. The method according to claim 6, wherein the second threshold value is lower than the first threshold value.

8. A system for depicting a position of a catheter, the system comprising:

a detector configured to obtain first and second measurements of a magnetic field produced by a permanent magnet positioned at a distal end of the catheter, wherein a first detection zone and a second detection zone are defined relative to the detector;

a processor in communication with the detector, wherein the processor is configured to;

receive the first measurements from the detector;

compare the first measurements with a model of the permanent magnet;

provide a first confidence level regarding a first position of the permanent magnet;

receive the second measurements from the detector;

compare the second measurements with the model of the permanent magnet; and

provide a second confidence level regarding a second position of the permanent magnet; and

a display device configured to show an image representative of the permanent magnet, wherein the system is configured to show an initial display of the image only if the first confidence level is above a first threshold value and the first position is within the first detection zone, and wherein the system is configured to show a subsequent display of the image if the second confidence level is above a second threshold value different from the first threshold value and the second position is within one or more of the first and second detection zones.

9. The system according to claim 8, wherein the permanent magnet comprises a plurality of permanent magnetic materials.

10. The system according to claim 8, wherein the permanent magnet is associated with a stylet that is removably inserted into a lumen of the catheter.

11. A method for displaying a position of a medical device during placement of the medical device into a patient using a system including a processor, the method comprising:

(a) obtaining a first set of detected position data relating to a permanent magnet associated with the medical device;

(b) determining a possible first position of the permanent magnet;

(c) assigning a first confidence level relating to a match between the first set of detected position data and a first set of predicted position data relating to the possible first position;

(d) determining that the first confidence level meets or exceeds a first threshold;

(e) determining that the first position of the permanent magnet is within a first detection zone if the first confidence level meets or exceeds the first threshold;

(f) displaying the first position of the permanent magnet if the first position is within the first detection zone;

(g) obtaining a second set of detected position data relating to the permanent magnet;

(h) determining a possible second position of the permanent magnet;

(i) assigning a second confidence level relating to a match between the second set of detected position data and a second set of predicted position data relating to the possible second position;

(j) determining that the second confidence level meets or exceeds a second threshold different from the first threshold;

(k) determining that the second position of the permanent magnet is within at least one of the first detection zone and a second detection zone if the second confidence level meets or exceeds the second threshold; and

(l) displaying the second position of the permanent magnet if the second position of the permanent magnet is within at least one of the first detection zone and the second detection zone.

12. The method according to claim 11, wherein determining a possible first position of the permanent magnet is performed via a neural net best fit algorithm;

and wherein the first detection zone at stage (i) includes dimensions larger than when the first set of detected position data was obtained at stage (a).

13. The method according to claim 11, further comprising calibrating the system before executing stage (a).

14. The method according to claim 11, wherein stage (k) further comprises:

ensuring that the second position of the permanent magnet is within a predetermined distance range from the first position of the permanent magnet within a predetermined amount of time.

15. The method according to claim 11, wherein the first position and the second position of the permanent magnet are defined with respect to an X, Y, Z coordinate axis grid including an origin at or proximate to the detector, and wherein a depth of the first detection zone is at least 8 cm.

16. The method according to claim 11, wherein at least stages (b) and (c) are repeatedly executed in succession a predetermined number of times before stage (d) is executed.

17. The method according to claim 11, wherein a shape of at least one of the first and second detection zones is selected from the list consisting of:

square box, rectangular box, triangular volume, spherical, ellipsoid; and

paraboloid.

18. A computer program product for implementing a method for displaying a position of a medical device during placement of the medical device into a patient, the computer program product including one or more non-transitory computer-readable media having stored thereon computer executable instructions that, when executed by a processor, cause a computer system to perform the following:

(a) obtain a first set of detected position data relating to a permanent magnet associated with the medical device;

(b) determine a possible first position of the permanent magnet;

(c) assign a first confidence level relating to a match between the first set of detected position data and a first set of predicted position data relating to the possible first position;

(d) determine that the first confidence level meets or exceeds a first threshold;

(e) determine that the first position of the permanent magnet is within a first detection zone if the first confidence level meets or exceeds the first threshold;

(f) display the first position of the permanent magnet if the first position is within the first detection zone;

(g) obtain a second set of detected position data relating to the permanent magnet;

(h) determine a possible second position of the permanent magnet;

(i) assign a second confidence level relating to a match between the second set of detected position data and a second set of predicted position data relating to the possible second position;

(j) determine that the second confidence level meets or exceeds a second threshold different from the first threshold;

(k) determine that the second position of the permanent magnet is within at least one of the first detection zone and a second detection zone if the second confidence level meets or exceeds the second threshold; and

(l) display the second position of the permanent magnet if the second position of the permanent magnet is within at least one of the first detection zone and the second detection zone.