In adults, where is the tube-to-teeth mark typically located when an ET tube is placed?

When an endotracheal (ET) tube is correctly placed in adults, the typical tube-to-teeth mark is generally found around 22 cm at the lip or teeth. This distance can vary somewhat based on the individual's anatomy, particularly in different populations, but 22 cm is widely accepted as the standard measurement for adult patients.

This placement is important because it helps ensure that the distal tip of the ET tube is positioned just above the carina (the point where the trachea splits into the bronchi) to facilitate optimal ventilation. Correctly marking this distance also provides a reliable way to verify the tube's position in case of accidental displacement. While some variability in positioning may occur due to anatomical differences, 22 cm serves as a useful benchmark for effective airway management in adults.