What is the most important nursing action to assess the proper positioning of an endotracheal (ET) tube?

The most important nursing action to assess the proper positioning of an endotracheal (ET) tube is to listen for bilateral breath sounds. This action is critical because it provides direct evidence that the ET tube is correctly placed in the trachea rather than in the esophagus or in one of the bronchial tubes. When the ET tube is properly positioned, airflow will equally reach both lungs, resulting in the presence of equal and bilateral breath sounds upon auscultation.

If breath sounds are absent or diminished on one side, it may indicate that the tube has been incorrectly placed, possibly leading to inadequate ventilation and hypoxia in the patient. Therefore, assessing for bilateral breath sounds is a key indicator of the ET tube’s proper placement and functionality.

Monitoring respiratory rate, observing for chest expansion, and checking the patient's sedation level, while important in overall patient assessment and management, do not specifically confirm the correct positioning of the ET tube in the same direct manner that auscultating for breath sounds does.