Flexible bronchoscopy during percutaneous dilatational tracheostomy (PDT) has become the standard of care to eliminate paratracheal misplacement of the tracheostomy tube and reduce damage to the posterior tracheal wall, and as a safety precaution for easy reintubation in case of accidental extubation.1 Another underappreciated advantage of flexible bronchoscopy is the recognition of unanticipated anatomic defects before performing the procedure. We describe a case of herniated tracheal rings, which was incidentally detected during preprocedure bronchoscopy.
A 49-year-old black woman was transferred from an outside hospital with tracheobronchitis and status asthmaticus requiring mechanical ventilation. Over the next 10 days the patient did not meet extubation criteria due to frequent suctioning and low tidal volumes. The interventional pulmonology team was consulted for performing PDT. The flexible bronchoscopy during the PDT revealed 4 consecutive tracheal rings, visible after endotracheal tube retraction, which were herniated and completely exposed through the mucosa into the tracheal lumen (Fig. 1). There was no fracture of these rings. There was minimal erythema of the mucosa at that level.
The tracheostomy was aborted. On repeat bronchoscopy, 2 of the tracheal rings were partially resected at their mucosal base using an electrocautery snare (Olympus America Inc., Center Valley, PA) at 20 watts (Fig. 2). Approximately 2 cm of each ring was removed. There was no immediate tracheomalacia visualized. Over the next 3 days the secretions greatly decreased and the patient was successfully extubated.
Approximately 6 weeks after tracheal ring removal and extubation, the patient presented with progressive dyspnea and variable intrathoracic obstruction on the flow volume loop. On rigid bronchoscopy, there was 3.5 cm of distal tracheal stenosis at the site of the previously herniated tracheal rings. The trachea was approximately 8 mm in diameter. The stenosis was dilated with rigid dilators to 34-French and a 14×40-mm Tracheobronxane Dumon silicon tracheal stent (Novatech; France) was placed. The patient tolerated the procedure well and was discharged on postoperative day 1.
Although we cannot confirm the exact cause of ring herniation, the most likely pathogenesis is mucosal necrosis from pressure-related ischemia. Mucosal ischemia results from an overinflated endotracheal cuff obstructing the mucosal blood supply.2 Necrosis is worsened by direct trauma during intubation and infection.3 This case represents an often unseen early phase of postintubation tracheal stenosis. These lesions are an acute mucosal injury, which with healing over the next several weeks resulted in cicatricial tracheal stenosis. This case also reinforces the need for bronchoscopy with PDT. This is to rule out unanticipated airway lesions contributing to extubation failure in addition to direct visualization for the proper placement of the tracheostomy tube.
1. deBoisblanc BP. Percutaneous dilational tracheostomy techniques. Clin Chest Med. 2003;24:399–407.
2. Seegobin RD, Van Hasselt GL. Endotracheal cuff pressure and tracheal mucosal blood flow: endoscopic study of effects of four large volume cuffs. Br Med J (Clin Res Ed). 1984;288:965–968.
3. Sue RD, Swan IS. Long-term complications of artificial airways. Clin Chest Med. 2003;24:457–471.