Location determining endotracheal tube and methods

Patent metadata

Field	Value
Publication number	US-10058669-B2
Application number	US-201314405811-A
Country	US
Kind code	B2
Filing date	Jun 5, 2013
Priority date	Jun 5, 2012
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

A system for aiding in the proper placement of an endotracheal tube in the trachea of a patent includes an endotracheal tube having a proximal region and a distal region. At least one electrode is included on the distal region to provide an electrical stimulation signal to patient tissue. The system includes a control unit coupled to the electrode and configured to differentiate proper placement of the endotracheal tube in the patient's trachea from improper placement of the endotracheal tube in the patient's esophagus based on a sensed response to the electrical stimulation provided by the electrode.

First claim

What is claimed is:

1. A system for aiding in the proper placement of an endotracheal tube in the trachea of a patient, comprising:
an endotracheal tube having a proximal region and a distal region;
a first electrode configured to provide an electrical stimulation signal to patient tissue;
a second electrode at the distal region of the endotracheal tube configured to sense an electromyographic response generated by patient tissue; and
a control unit coupled to the first and second electrodes and configured to differentiate proper placement of the endotracheal tube in the patient's trachea from improper placement of the endotracheal tube in the patient's esophagus based on an electromyographic response sensed by the second electrode generated by patient tissue proximate the distal region of the endotracheal tube in response to the electrical stimulation provided by the first electrode.

2. The system of claim 1 wherein the distal region of the endotracheal tube includes, in addition to the second electrode, at least a third electrode selected from the group consisting of an electrode configured to provide electrical stimulation to patient tissue and an electrode configured to sense an electrical response from patient tissue, wherein the second and third electrodes are each coupled to the control unit.

3. The system of claim 2 wherein the first and second electrodes are each at the distal region of the endotracheal tube, and wherein the control unit is configured to provide an electrical stimulation signal to the first electrode and is configured to sense the electromyographic response on the second electrode.

4. The system of claim 1 wherein the first electrode comprises an external electrode configured to be placed outside the patient's body and to be coupled to the control unit.

5. The system of claim 4 wherein the control unit is configured to provide an electrical stimulation signal to the external electrode and is configured to sense the electromyographical response received from the second electrode.

6. The system of claim 1 wherein a location of the first electrode on the distal region is user adjustable.

7. The system of claim 1 wherein the distal region includes the first electrode, the second electrode, and at least a third electrode selected from the group consisting of an electrode configured to provide electrical stimulation to patient tissue and an electrode configured to sense an electrical response from patient tissue.

8. The system of claim 1 wherein the distal region includes a plurality of the first electrodes configured to provide an electrical stimulation signal to patient tissue and a plurality of the second electrodes configured to sense an electrical response from patient tissue.

9. The system of claim 1 wherein the control unit is configured to perform a plurality of algorithms to differentiate placement in the esophagus from placement in the trachea.

10. The system of claim 9 wherein the algorithms include at least one of a frequency algorithm, a slope algorithm and an averaging algorithm.

11. The system of claim 1 wherein the control unit includes an indicator that indicates whether the endotracheal tube is improperly in the patient's esophagus.

12. A system for aiding in the proper placement of an endotracheal tube in the trachea of a patient, comprising:
an endotracheal tube having a proximal region and a distal region, the distal region including an electrode;
a control unit coupled to the electrode configured to differentiate proper placement of the endotracheal tube in the patient's trachea from improper placement of the endotracheal tube in the patient's esophagus based on an electrical response sensed by an electrode contacting patient tissue proximate the distal region of the endotracheal tube;
wherein the control unit is configured to convert the sensed electrical response from a time domain to a frequency domain to produce frequency domain data, and is configured to determine whether a maximum value of the frequency domain data over a predetermined frequency range is greater than a threshold.

13. The system of claim 12 wherein the predetermined frequency range is approximately 6 to 10 Hz.

14. The system of claim 12 wherein the control unit is configured to determine that the endotracheal tube has been improperly placed in the patient's esophagus if the maximum value of the frequency domain data over the predetermined frequency range is greater than the threshold.

15. The system of claim 14 wherein, if the maximum value of the frequency domain data over the predetermined frequency range is less than the threshold, the control unit is configured to perform both a slope algorithm and an averaging algorithm and is configured to determine that the endotracheal tube has been properly placed in the patient's trachea if both the slope and averaging algorithms confirm placement in the trachea.

16. The system of claim 15 wherein the control unit is configured to perform the slope algorithm by:
computing a least squares linear regression fit for the sensed electrical response for a predetermined time period after a stimulation signal generated by the control unit has ended, the least squares linear regression fit including a slope value;
determining that the endotracheal tube is improperly in the patient's esophagus if the slope value is greater than a slope threshold; and
determining that the endotracheal tube is properly in the patient's trachea if the slope value is less than the slope threshold.

17. The system of claim 16 wherein the predetermined time period is approximately 0.15 seconds.

18. The system of claim 15 wherein the control unit is configured to perform the averaging algorithm by:
computing a first average value of the sensed electrical response for a first predetermined time period before a stimulation signal generated by the control unit;
computing a second average value of the sensed electrical response for a second predetermined time period after a stimulation signal generated by the control unit;
subtracting the second average value from the first average value to produce a difference value;
determining that the endotracheal tube is improperly in the patient's esophagus if the difference value is greater than an average threshold value; and
determining that the endotracheal tube is properly in the patient's trachea if the difference value is less than the average threshold value.

19. The system of claim 18 wherein the first predetermined and second time periods are approximately 0.05 seconds and the average threshold value is approximately 0.00125 volts.

20. A method for aiding in the proper placement of an endotracheal tube in the trachea of a patient, the endotracheal tube comprising a proximal region and a distal region and at least one sensing electrode on the distal region, the method comprising:
activating a user control on a control unit;
electrically stimulating patient tissue;
receiving an electromyographic signal sensed by the sensing electrode on the distal region of the endotracheal tube, the electromyographic signal being responsive to stimulating the patient tissue;
determining whether the endotracheal tube is improperly in the patient's esophagus based on the received signal.

21. The method of claim 20 wherein electrically stimulating patient tissue comprises providing an electrical stimulation signal to a stimulation electrode in contact with the patient tissue.

22. The method of clai

Assignees

• Texas Heart Inst

Inventors

• Razavi Mehdi
• Levert Christopher
• Wagner Sarah
• Terry Robin
• Kosh Michael
• Nathan Joanna

Classifications

• A61B5/04884

  Human Necessities · mapped topic

• A61N1/0519

  Endotracheal electrodes · CPC title

• A61M16/044

  External cuff pressure control or supply, e.g. synchronisation with respiration · CPC title

• A61M2230/65

  Impedance, e.g. conductivity, capacity · CPC title

• A61B5/6853

  with a balloon · CPC title