Right atrium indicator

• US 9,345,447 B2
• Filed: 03/14/2013
• Issued: 05/24/2016
• Est. Priority Date: 05/07/2012
• Status: Active Grant

• Current Assignee: Teleflex Life Sciences LLC (Teleflex Incorporated)
• Original Assignee: Vasonova, Inc. (Teleflex Incorporated)
• Inventors: Wenzel, Brian J., Lee, Kichang, Hanlon, Stephen P., Navratil, Miroslav, Jiang, Jin
• Primary Examiner(s): Peng, Bo J
• Application Number:
  US13/829,522
• Publication Number:
  US 20130296693A1
• Time in Patent Office: 1,167 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2034/2063 Acoustic tracking systems, e.g. using ultrasound
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/061 Determining position of a probe within the body employing means separate from the probe, e.g. sensing internal probe position employing impedance electrodes on the surface of the body A61B1/00158 takes precedence
• CPC Class Codes: A61B 5/065 Determining position of the probe employing exclusively positioning means located on or in the probe, e.g. using position sensors arranged on the probe
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/353 Detecting P-waves
• CPC Class Codes: A61B 5/355 Detecting T-waves
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: A61B 8/0841 for locating instruments
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61B 8/488 involving Doppler signals

Abstract

A method for determining the location of a medical device within a body is provided. The method includes transmitting from the medical device an acoustic signal; receiving with the medical device a reflected acoustic signal; advancing the medical device based on a first algorithm, the first algorithm including a first weighting factor and a first feature extracted from the reflected acoustic signal; determining a first location of the medical device based on the first algorithm; and moving the medical device to a second location based on a second algorithm, the second algorithm based on the determined first location and including at least one of a second weighting factor and a second feature extracted from the reflected acoustic signal. Also disclosed are systems and devices for performing the methods described herein.

Claims

1. A method for determining that a distal region of a medical device has entered the right atrium of a patient, the method comprising:

transmitting, from a non-imaging ultrasound transducer of the medical device, an acoustic signal;

receiving, using the non-imaging ultrasound transducer of the medical device, a reflected acoustic signal;

detecting, using an electrocardiogram sensor of the medical device, an electrocardiogram signal;

extracting one or more acoustic features from the reflected acoustic signal;

extracting one or more electrocardiogram features from the electrocardiogram signal;

determining that the distal region of the medical device has entered the right atrium of the patient based on the one or more acoustic features and the one or more electrocardiogram features; and

visually indicating, in response to the determination that the distal region of the medical device has entered the right atrium of the patient, that the distal region of the medical device has entered the right atrium of the patient.

2. The method of claim 1, wherein the one or more acoustic features comprise a frequency content of the reflected acoustic signal over time.

3. The method of claim 2, wherein determining that the distal region of the medical device has entered the right atrium of the patient based on the one or more acoustic features and the one or more electrocardiogram features comprises determining that the distal region of the medical device has entered the right atrium of the patient when the frequency content of the acoustic signal over time changes between antegrade dominant and retrograde dominant while the medical device is not being advanced or retracted.

4. The method of claim 3, wherein the frequency content of the acoustic signal over time changes between antegrade dominant and retrograde dominant at a frequency of 7 kHz to 15 kHz.

5. The method of claim 1, wherein the one or more acoustic features comprise an antegrade power signal, a retrograde power signal, a ratio of the antegrade power signal to the retrograde power signal, or an overall power of the reflected acoustic signal.

6. The method of claim 5, wherein determining that the distal region of the medical device has entered the right atrium of the patient based on the one or more acoustic features and the one or more electrocardiogram features comprises determining that the distal region of the medical device has entered the right atrium of the patient when an average value of the antegrade power signal is equal to the retrograde power signal over a cardiac cycle.

7. The method of claim 1, further comprising:

generating a Mel-frequency cepstrum of the reflected acoustic signal; and

determining one or more coefficients of the Mel-frequency cepstrum.

8. The method of claim 7, further comprising comparing the determined one or more coefficients with a database of coefficients based on turbulent and non-turbulent blood flow.

9. The method of claim 1, further comprising monitoring respiration of the patient and removing respiratory artifacts from the reflected acoustic signal based on the monitored respiration of the patient.

10. The method of claim 1, wherein determining that the distal region of the medical device has entered the right atrium of the patient based on the one or more acoustic features and the one or more electrocardiogram features comprises determining a plurality of scores for a plurality of membership functions, each membership function comprising a series of extracted features, and each extracted feature modified by a weighting factor.

11. The method of claim 1, wherein the one or more electrocardiogram features comprise the R-wave of the electrocardiogram signal.

12. The method of claim 1, wherein the one or more electrocardiogram features comprise bi-phasic P wave characteristics of the electrocardiogram signal.

13. The method of claim 1, wherein visually indicating that the distal region of the medical device has entered the right atrium of the patient comprises displaying a red or orange indicator.

14. The method of claim 1, wherein determining that the distal region of the medical device has entered the right atrium of the patient comprises determining that the distal region of the medical device has passed the superior vena cava of the patient.

15. A system for determining that a distal region of a medical device has entered the right atrium of a patient, the system comprising:

an elongate body having a non-imaging ultrasound transducer and an electrocardiogram sensor disposed on a distal portion of the elongate body, the non-imaging ultrasound transducer being configured to transmit an acoustic signal and receive a reflected acoustic signal, and the electrocardiogram sensor being configured to detect an electrocardiogram signal;

a processor configured to receive and process the reflected acoustic signal from the non-imaging ultrasound transducer and the electrocardiogram signal from the electrocardiogram sensor; and

memory for storing instructions, which when executed by the processor, that cause the processor to;

extract one or more acoustic features from the reflected acoustic signal;

extract one or more electrocardiogram features from the electrocardiogram signal;

determine that the distal region of the elongate body has entered the right atrium of the patient based on the one or more acoustic features and the one or more electrocardiogram features; and

visually indicate, in response to the determination that the distal region of the medical device has entered the right atrium of the patient, that the distal region of the medical device has entered the right atrium of the patient.

16. The system of claim 15, wherein the one or more acoustic features includes comprise a frequency content of the reflected acoustic signal over time.

17. The system of claim 16, wherein the memory further comprises instructions, which when executed by the processor, that cause the processor to determine that the distal portion of the elongate body has entered the right atrium of the patient when the frequency content of the acoustic signal over time changes between antegrade dominant and retrograde dominant while the elongate body is not being advanced or retracted.

18. The system of claim 15, wherein the one or more acoustic features includes comprise an antegrade power signal, a retrograde power signal, a ratio of the antegrade power signal to the retrograde power signal, or an overall power of the reflected acoustic signal.

19. The system of claim 18, wherein the memory further comprises instructions, which when executed by the processor, that cause the processor to determine that the distal portion of the elongate body has entered the right atrium of the patient when an average value of the antegrade power signal is equal to the retrograde power signal over a cardiac cycle.

20. The system of claim 15, wherein the memory further comprises instructions, which when executed by the processor, that cause the processor to:

generate a Mel-frequency cepstrum of the reflected acoustic signal; and

determine one or more coefficients of the Mel-frequency cepstrum.

21. The system of claim 20, wherein the memory further comprises instructions, which when executed by the processor, that cause the processor to compare the determined one or more coefficients with a database of coefficients based on turbulent and non-turbulent blood flow.

22. The system of claim 15, wherein the memory further comprises instructions, which when executed by the processor, that cause the processor to remove respiratory artifacts from the reflected acoustic signal based on monitored respiration of the patient.