Prehospital Trauma Life Support (PHTLS) Practice Test

Which is the preferred adjunct device for verifying placement of an endotracheal tube in a patient with a perfusing rhythm?

1. End-tidal CO2 monitoring (capnography)

2. Esophageal detector device

3. Pulse oximeter

4. Stethoscope

The correct answer is: End-tidal CO2 monitoring (capnography)

The preferred adjunct device for verifying placement of an endotracheal tube in a patient with a perfusing rhythm is end-tidal CO2 monitoring (capnography). This device measures the concentration of carbon dioxide in exhaled air, which is indicative of proper placement of the tube in the trachea. When the tube is correctly placed in the trachea, carbon dioxide will be present in the exhaled breath because it is a byproduct of cellular metabolism. The presence of capnography waveform tracts and a consistent CO2 reading validate that the tube is not in the esophagus, thus confirming correct placement. Other devices, while useful in certain contexts, do not provide the same level of reliable confirmation. For example, an esophageal detector device can indicate whether an endotracheal tube is in the esophagus, but it does not confirm tracheal placement. A pulse oximeter measures oxygen saturation in the blood, which can be influenced by multiple variables unrelated to endotracheal placement, thus it is not a direct indicator of tube placement. Finally, a stethoscope is commonly used to listen for breath sounds, but it is subjective and can easily miss improper placements. Hence, capnography is considered