A 68-year-old male with COPD is intubated in the ICU for acute respiratory failure. On day 5 of mechanical ventilation, he develops stridor and difficulty with tube passage during a planned reintubation. What is the most common site of endotracheal tube-related stenosis?

## Endotracheal Tube-Related Stenosis: Site of Injury **Key Point:** The subglottic region at the level of the cricoid cartilage is the most common site of post-intubation stenosis, accounting for 60–75% of cases. ### Anatomical Basis The cricoid cartilage forms a complete ring and is the narrowest part of the pediatric airway. In adults, the subglottic region is vulnerable because: 1. The tube cuff exerts pressure on the soft tissues between the tube and the rigid cricoid ring 2. The mucosa is thin and has limited collateral blood supply in this region 3. Prolonged cuff pressure (>25 cm H₂O) causes mucosal ischemia and ulceration 4. Healing by fibrosis leads to scar contracture and stenosis ### Comparison of Sites of Injury | Site | Frequency | Mechanism | Clinical Presentation | |------|-----------|-----------|----------------------| | **Subglottic (cricoid)** | 60–75% | Cuff pressure on mucosa | Stridor, difficulty with reintubation | | Glottic (vocal cords) | 10–15% | Direct tube trauma, vocal cord paralysis | Hoarseness, breathy voice | | Tracheal (cuff site) | 10–15% | Cuff pressure, tube movement | Dyspnea, stridor | | Posterior pharynx | Rare | Tube pressure against wall | Dysphagia | **High-Yield:** Subglottic stenosis is the most common serious complication of prolonged intubation and is preventable by maintaining cuff pressures <25 cm H₂O and minimizing tube duration. **Clinical Pearl:** Subglottic stenosis typically presents 2–8 weeks after extubation as progressive stridor and dyspnea, whereas acute post-extubation stridor (within 24–48 hours) is usually due to laryngeal edema, not stenosis. **Mnemonic:** **CRICOID** = **C**ritical site for stenosis; **R**igid ring; **I**schemia from cuff; **C**ontracture from fibrosis; **O**ften overlooked in prevention; **I**njury preventable; **D**iagnosed late. ### Prevention Strategies - Maintain cuff pressure 20–25 cm H₂O (check with manometer) - Minimize intubation duration; use tracheostomy if >7–10 days anticipated - Use high-volume, low-pressure cuffs - Avoid tube movement and self-extubation - Regular cuff pressure monitoring in ICU patients