ACE Sample Question
Your patient is undergoing a general anesthetic using an endotracheal tube (ETT) through a mature tracheostomy. What is the OPTIMAL depth of the ETT (read from the skin surface of the tracheostomy) to ensure the tip of the ETT is safely positioned?
Answer: A. 5 cm. Read the discussion below.
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Tracheostomies are placed between the second and third, or the third and fourth, tracheal cartilage. Placement at a higher level increases the risk of subglottic stenosis, while placement below the fifth tracheal cartilage increases the risk that a tracheal tube will dislodge. The reported length of the trachea from the inferior portion of the larynx to the carina ranges from 10 to 13 cm and is composed of approximately 20 U-shaped cartilaginous rings.
For patients with mature tracheostomies who are having further head and neck procedures, it is advantageous to remove the existing tracheostomy tube and insert a wire-reinforced endotracheal tube (ETT) through the stoma, pulling it back after placement until the top of the ETT cuff can be visualized. Placement of an ETT through a mature tracheostomy should not extend past 5 to 6 cm to avoid risking carinal irritation or endobronchial intubation (Figure 1).
Figure 1. Placement of an endotracheal tube through a mature tracheostomy. © 2021 American Society of Anesthesiologists.
As opposed to mature tracheostomies, recently created tracheostomies may be safely managed using an exchange technique or a fiberoptic bronchoscope, and position may be assessed using direct visualization.
Patiño MA, Truong DT, Truong A, Cata JP. Do not burn your airway bridge: a technique to safely exchange a tracheostomy tube for a tracheal tube. A A Case Rep. 2016;7(7):155-157. doi:10.1213/XAA.0000000000000368