Acoustic detection of endotracheal tube location

• US 20030018276A1
• Filed: 07/01/2002
• Published: 01/23/2003
• Est. Priority Date: 10/06/2000
• Status: Active Grant

• Current Assignee: Biomedical Acoustic Research Corporation
• Original Assignee: Biomedical Acoustic Research Corporation
• Inventors: Mansy, Hansen A., Sandler, Richard H.
• Granted Patent: US 8,394,031 B2
• Time in Patent Office: Days
• US Class Current: 600/529
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R

Abstract

A system and method for use in detecting an endotracheal tube location within a body electronically detects indigenous breath sounds emanating from a region of the body and processes the detected indigenous breath sounds to generate a parameter representative of an acoustic characteristic of the body associated with the endotracheal tube location within the body. The system and method generates an output indicative of the endotracheal tube location within the body based on the parameter representative of the acoustic characteristic of the body.

Claims

1. A method of detecting an endotracheal tube location within a body, the method comprising the steps of:

electronically detecting indigenous breath sounds emanating from a region of the body;

processing the detected indigenous breath sounds to generate a parameter representative of an acoustic characteristic of the body associated with the endotracheal tube location within the body; and

generating an output indicative of the endotracheal tube location within the body based on the parameter representative of the acoustic characteristic of the body.

2. The method of claim 1, wherein electronically detecting the indigenous breath sounds emanating from the region of the body includes receiving an electrical signal from an acoustic sensor disposed adjacent to one of a chest region of the body and an epigastric region of the body.

3. The method of claim 1, wherein electronically detecting the indigenous breath sounds emanating from the region of the body includes receiving a first electrical signal from a first acoustic sensor disposed adjacent to a left side chest region of the body and receiving a second electrical signal from a second acoustic sensor disposed adjacent to a right side chest region of the body.

4. The method of claim 1, wherein processing the detected indigenous breath sounds to generate the parameter representative of the acoustic characteristic of the body associated with the endotracheal tube location within the body includes calculating a spectral energy ratio.

5. The method of claim 4, wherein calculating the spectral energy ratio includes converting the detected indigenous breath sounds into digital information and using a fast Fourier transform to calculate the spectral energy ratio.

6. The method of claim 4, wherein calculating the spectral energy ratio includes dividing a first spectral energy value associated with a first chest region of the body by a second spectral energy value associated with a second chest region of the body.

7. The method of claim 1, wherein processing the detected indigenous breath sounds to generate the parameter representative of the acoustic characteristic of the body associated with the endotracheal tube location within the body includes calculating one of a mean spectral difference and a time delay.

8. The method of claim 1, wherein generating the output indicative of the endotracheal tube location within the body based on the parameter representative of the acoustic characteristic of the body includes comparing the parameter representative of the acoustic characteristic of the body to a baseline value associated with a non-intubated condition of the body.

9. The method of claim 1, wherein generating the output indicative of the endotracheal tube location within the body based on the parameter representative of the acoustic characteristic of the body includes generating one of a visual and an audible indication of the endotracheal tube location.

10. The method of claim 1, wherein generating the output indicative of the endotracheal tube location within the body based on the parameter representative of the acoustic characteristic of the body includes generating an output indicative of one of a tracheal location, an esophageal location and a mainstem location.

11. The method of claim 1, further including electronically detecting ventilation cycle timing information of the body and using the ventilation cycle timing information to process the detected indigenous breath sounds.

12. The method of claim 1, wherein processing the detected indigenous breath sounds to generate the parameter representative of the acoustic characteristic of the body associated with the endotracheal tube location within the body includes discarding data associated with a portion of the detected indigenous breath sounds having a low signal-to-noise ratio.

13. The method of claim 12, wherein discarding data associated with the portion of the detected indigenous breath sounds having a low signal-to-noise ratio includes discarding the data based on a predetermined threshold value.

14. The method of claim 1, wherein electronically detecting the indigenous breath sounds emanating from the region of the body includes detecting indigenous breath sounds emanating from an epigastric region of the body.

15. The method of claim 14, wherein processing the detected indigenous breath sounds to generate the parameter representative of the acoustic characteristic of the body associated with the endotracheal tube location within the body includes calculating a temporal characteristic of the indigenous breath sounds emanating from the epigastric region of the body.

16. The method of claim 15, wherein generating the output indicative of the endotracheal tube location within the body based on the parameter representative of the acoustic characteristic of the body includes generating an output indicative of an esophageal location of the endotracheal tube within the body based on the temporal characteristics of the indigenous breath sounds emanating from the epigastric region of the body.

17. The method of claim 1, wherein electronically detecting the indigenous breath sounds emanating from the region of the body includes electronically detecting indigenous breath sounds associated with a left chest region of the body and detecting indigenous breath sounds associated with a right chest region of the body.

18. The method of claim 17, wherein processing the detected indigenous breath sounds to generate the parameter representative of the acoustic characteristic of the body associated with the endotracheal tube location within the body includes calculating a time delay between the indigenous breath sounds associated with the left chest region and the indigenous breath sounds associated with the right chest region.

19. The method of claim 18, wherein generating the output indicative of the endotracheal tube location within the body based on the parameter representative of the acoustic characteristic of the body includes generating an output indicative of a mainstem location of the endotracheal tube within the body based on the time delay between the indigenous breath sounds associated with the left chest region and the indigenous breath sounds associated with the right chest region.

20. The method of claim 1, further including generating a low signal level indication in response to a determination that the detected indigenous breath sounds are below a predetermined threshold value.

21. The method of claim 1, further including generating a baseline value for comparison to the parameter representative of the acoustic characteristic.

22. The method of claim 21, wherein generating the baseline value includes generating the baseline value based on one of historical breath sounds data, a mask-ventilated condition of the body, and a tracheally intubated condition of the body.

23. The method of claim 1, wherein processing the detected indigenous sounds to generate the parameter representative of the acoustic characteristic of the body includes using an adaptive filtering technique to filter noise.

25. The system of claim 24, wherein the acoustic sensor is adapted to be disposed adjacent to one of a chest region of the body and an epigastric region of the body.

26. The system of claim 24, wherein the acoustic sensor is adapted to be disposed adjacent to a left side chest region of the body and further including another acoustic sensor that is adapted to be disposed adjacent to a right side chest region of the body.

27. The system of claim 24, wherein the processing unit is adapted to generate the parameter representative of the acoustic characteristic of the body associated with the endotracheal tube location within the body by calculating a spectral energy ratio.

28. The system of claim 24, wherein the processing unit is adapted to calculate the spectral energy ratio by converting the signal into digital information and using a fast Fourier transform to convert the digital information into spectral information.

29. The system of claim 28, wherein the processing unit is adapted to calculate the spectral energy ratio by dividing a first spectral energy value associated with a first chest region of the body by a second spectral energy value associated with a second chest region of the body.

30. The system of claim 24, wherein the processing unit is adapted to generate the parameter representative of the acoustic characteristic of the body associated with the endotracheal tube location within the body by calculating one of a mean spectral difference and a time delay.

31. The system of claim 24, wherein the output indicative of the endotracheal tube location within the body is based on a comparison of the parameter representative of the acoustic characteristic of the body to a baseline value associated with a non-intubated condition of the body.

32. The system of claim 24, wherein the output device is adapted to generate one of a visual and an audible indication of the endotracheal tube location.

33. The system of claim 24, wherein the output device is adapted to generate one of an output indicative of one of a tracheal location, an esophageal location and a mainstem location.

34. The system of claim 24, further including an airflow sensor that is adapted to electronically detect ventilation cycle timing information of the body, and wherein the processing unit is adapted to use the ventilation cycle timing information to process the signal.

35. The system of claim 24, wherein the processing unit is adapted to discard data associated with a portion of the signal having a low signal-to-noise ratio.

36. The system of claim 35, wherein the processing unit is adapted to discard the data based on a predetermined threshold value.

37. The system of claim 24, wherein the acoustic sensor is adapted to electronically detect the indigenous breath sounds emanating from an epigastric region of the body.

38. The system of claim 37, wherein the processing unit is adapted to generate the parameter representative of the acoustic characteristic of the body associated with the endotracheal tube location within the body by calculating a temporal characteristic of the signal based on the temporal characteristic.

39. The system of claim 38, wherein the output device is adapted to generate an output indicative of an esophageal location of the endotracheal tube within the body.

40. The system of claim 24, wherein the acoustic sensor is adapted to detect indigenous breath sounds associated with a left chest region of the body and further including a second acoustic sensor that is adapted to detect indigenous breath sounds associated with a right chest region of the body.

41. The system of claim 40, wherein the processing unit is adapted to generate the parameter representative of the acoustic characteristic of the body associated with the endotracheal tube location within the body by calculating a time delay between the indigenous breath sounds associated with the left chest region and the indigenous breath sounds associated with the right chest region.

42. The system of claim 42, wherein the output device is adapted to generate an output indicative of a mainstem location of the endotracheal tube within the body based on the time delay.

43. The system of claim 24, wherein the output device is adapted to generate a low signal level indication in response to a determination that the signal is below a predetermined threshold value.

44. The system of claim 24, wherein the processing unit is adapted to generate a baseline value for comparison to the parameter representative of the acoustic characteristic.

45. The system of claim 44, wherein the processing unit is adapted to generate the baseline value by generating the baseline value based on one of historical breath sounds data, a mask-ventilated condition of the body, and a tracheally intubated condition of the body.

46. The system of claim 24, wherein processing unit is adapted to generate the parameter representative of the acoustic characteristic of the body using an adaptive filtering technique to filter noise.

24. A system for use in detecting an endotracheal tube location within a body, the system comprising:

an acoustic sensor adapted to electronically detect indigenous breath sounds emanating from a region of the body;

a processing unit adapted to receive a signal from the acoustic sensor and to process the signal to generate a parameter representative of an acoustic characteristic of the body associated with the endotracheal tube location within the body; and

an output device adapted to generate an output indicative of the endotracheal tube location within the body based on the parameter representative of the acoustic characteristic of the body.