During endotracheal intubation, the endotracheal tube is attached to a capnometer. During the intubation procedure, the therapist observes the capnogram displayed below. How should the therapist interpret this finding?

Question

A. The ET tube has entered the trachea.
B. The ET tube is present in the esophagus.
C. The right mainstem bronchus has been intubated.
D. This finding is a common artifact that presents during CPR.

Answer 1

?ANS: A
A. Correct response: The fact that the capnogram tracing abruptly spiked from 0% exhaled CO2 to around 3% CO2 indicates that the endotracheal tube has entered the patient's trachea. Actually, with adequate perfusion and ventilation, one would expect to see an exhaled CO2 percent between 4.5% to 5.0%.
B. Incorrect response: If the endotracheal tube was placed into the esophagus, the capnogram would continue to read essentially 0% exhaled CO2. The capnogram would effectively demonstrate a flat line superimposed on the baseline. The first half of the drawing indicates esophageal intubation.
C. Incorrect response: If the therapist had intubated the right mainstem bronchus instead of the trachea, the capnogram would still indicate the tracing shown with this question because CO2 from the right lung would be detected by the capnometer. A portable AP chest x-ray must be performed to confirm the location of the tip of the endotracheal tube.
D. Incorrect response: See explanation A.