Which method is most reliable for verifying the placement of an endotracheal tube after intubation?

The most reliable method for verifying the placement of an endotracheal tube after intubation is checking for end-tidal carbon dioxide levels. This method is dependable because it provides physiological confirmation that the tube is positioned correctly within the trachea and that the lungs are ventilating adequately. When the tube is in the correct position, carbon dioxide from exhaled air is detected, typically using a capnometer, which measures the amount of carbon dioxide present in expired air. A strong and consistent reading of end-tidal carbon dioxide confirms proper placement in the airway, while a lack of detection may suggest the tube is misplaced, such as in the esophagus.

In contrast, listening for breath sounds can be subjective and may not accurately indicate whether the tube is in the trachea; some sounds could be transmitted or misleading. Observing chest expansion is also valuable but can be affected by various factors, including patient positioning and underlying lung conditions, and does not provide definitive proof of tube placement. Using a stethoscope on the abdomen is not a reliable method for verifying endotracheal tube placement, as sounds here could suggest improper placement in the esophagus rather than the trachea.