Method and system to determine correct tube placement during resuscitation

• US 20060011203A1
• Filed: 07/14/2005
• Published: 01/19/2006
• Est. Priority Date: 07/15/2004
• Status: Active Grant

• Current Assignee: Laerdal Medical AS (Laerdal Medical Corporation)
• Original Assignee: Laerdal Medical AS (Laerdal Medical Corporation)
• Inventors: Myklebust, Helge
• Granted Patent: US 7,774,054 B2
• Time in Patent Office: Days
• US Class Current: 128/207.140
• CPC Class Codes: A61B 5/0535 Impedance plethysmography for measuring blood flow A61B5/0295
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured

Abstract

System and method for controlling insertion of a tracheal tube in a patient, comprising at least two electrodes adapted to be coupled to the patients chest for providing impedance measurements, a measuring instrument for performing the impedance measurement, said instrument also being provided with storage means for storing a first data set representing chosen characteristics of the impedance change during a first measurement, and evaluation means for comparing the first data set with a second data set representing the characteristics of a second impedance measurement, for evaluating the difference between said measurements and providing an evaluation signal, said first and second data sets representing impedance variations measured during lung inflation with and without an inserted tracheal tube.

Claims

1. Method for controlling insertion of a tracheal tube in a patient comprising the steps of:

positioning at least two electrodes on the patients chest, said electrodes being coupled to a measuring instrument for measuring the impedance between the electrodes,

measuring the impedance variation while ventilating the patients lungs, e.g. using mask ventilation, and generating and storing a first data set representing the typical variation without intubation Zm,

inserting the tube into the trachea,

measuring the impedance variation while ventilating the patients lungs with the tube inserted therein and generating a second data set representing the typical variation with intubation Zt, and

evaluating the first and second data sets representing the change in impedance with and without the tube inserted, and based on this evaluation generating a signal being indicative of the difference between the sets.

2. Method according to claim 1, wherein said evaluation signal is a feedback to the user, indicating the need for retracting or adjusting the tube position.

3. Method according to claim 2, wherein each Zt and Zm is constituted by a single number representing the typical impedance change in each situation, e.g. the mean amplitude, and wherein the evaluation signal is a warning signal if Zt<

Zm.

4. Method according to claim 1, wherein said evaluation comprises the use of an adaptive filter.

5. Method according to claim 4, wherein the intubation is performed during chest compressions, said adaptive filter being adapted to filter out the chest compression artifacts in the impedance signal.

6. System for controlling insertion of a tracheal tube in a patient, comprising at least two electrodes adapted to be coupled to the patients chest for providing impedance measurements, a measuring instrument for performing the impedance measurement, said instrument also being provided with storage means for storing a first data set representing chosen characteristics of the impedance change during a first measurement, and evaluation means for comparing the first data set with a second data set representing the characteristics of a second impedance measurement, for evaluating the difference between said measurements and providing an evaluation signal, said first and second data sets representing impedance variations measured during lung inflation with and without an inserted tracheal tube.

7. System according to claim 6, wherein said evaluation means comprises display means for visually representing the data sets, e.g. graphically as curves on a screen, for manual evaluation of the differences between the sets.

8. System according to claim 6, wherein said first and second data sets represents the mean amplitude during chosen time windows, and said evaluation means being adapted to compare these means amplitudes.

9. System according to claim 6, comprising acoustic or visual means for providing a warning signal based on the evaluation.

10. System according to claim 6, being integrated in a defibrillator.