Airway management for tracheal stent extraction with the risk of re-occlusion through a tracheostomy orifice was performed safely using a double elastic bougies technique. The bougie-assisted cricothyrotomy method, in which an endotracheal tube is inserted using a gum elastic bougie as a guide, is used for surgical cricothyrotomy in emergency medicine to secure an emergency airway [7]. On the basis of the bougie-assisted cricothyrotomy, we developed a double gum elastic bougie technique for the airway management in this case. Since the double gum elastic bougie technique allows re-intubation orally or trans-tracheally by each bougie, this method might enable safe and constant maintenance of airway security.
In this case, a gum elastic bougie was placed through an oral intubation tube and a tracheostomy to maintain the airway during the procedures. In the case of acute airway obstruction associated with stent removal, the tracheal tube or tracheostomy tube may advance into the mediastinum or subcutaneously even if airway clearance is attempted through the tracheostomy orifice. At first, a gum elastic bougie was placed through the oral tracheal tube before starting the tracheal stent extraction. There were reasons for this bougie insertion. There was concern about the possibility of the orally inserted tracheal tube being accidentally removed before the tracheal orifice was established, and it was assumed that oral re-intubation would be difficult if drastic airway restenosis occurred due to emergency tracheal intubation-induced deterioration of the subglottic edema. The surgeon inserted the gum elastic bougie into the airway through the tracheostomy orifice and then removed the tracheal stent and could easily insert the tracheostomy tube. The bougie insertion via the tracheostomy orifice was necessary because there was a possibility of the trachea being obstructed by the tumor immediately after removal of the tracheal stent from the tracheostomy orifice. In that case, a tracheal tube had to be urgently inserted to secure the airway, and it served as a guidewire for this procedure. Our technique enabled maintenance of continuous airway management throughout the tracheal stent removal procedure.
Major complications of stents include lower respiratory tract infection, pneumonia, granulation, mucus retention and obstruction, hemoptysis, and stent deviation [9], with granulation reported in 0–20% of cases and migration and deviation reported in 10–22% of cases in which silicone stents were used [10]. In this case, it was considered that stent placement may cause edema at the end of the stent. The metal edge of the stent exerts circumferential pressure on the tissue and is likely to cause airway inflammation and subsequent granulation tissue formation [11]. Taking these factors into consideration, the subglottic space and the upper part of the trachea should be treated carefully because these areas are prone to granulation due to impaired mucosal blood flow caused by mechanical compression of the tracheal wall [12].
In this case, because of the appearance of laryngeal edema, it was difficult to remove the stent through the larynx. Thus, the tracheal stent had to be removed through a tracheostomy. It has been suggested that it is essential to maintain a width of at least 1 cm between the upper edge of the stent and the vocal folds to prevent discomfort and obstructive complications such as laryngeal edema, stent migration, and granulation tissue [13]. In this case, the distance between the superior edge of the stent and the vocal folds was about 1 cm, and the patient was at high risk of complications due to the stent.
Although there is no evidence regarding how general anesthesia should be managed and whether or not muscle relaxants should be used during stent placement [14], stent removal should be performed using a rigid bronchoscope under general anesthesia [15]. There have been reports of restenosis caused by granulation after stent removal, stent rupture during removal, and tracheal injury, although these occurred during metal stent removal. Careful treatment and airway management considering airway re-stenosis are therefore required [16,17,18]. In addition, stent extraction with rigid bronchoscopy is recommended to deal with complications during extraction [19]. The airway stimulation during stent extraction makes it difficult to maintain the depth of anesthesia, and management under spontaneous breathing is required in some cases. In this case, we chose sevoflurane to facilitate the adjustment of anesthesia depth. However, because adequate ventilation is a prerequisite for emergence from anesthesia with sevoflurane, anesthetic management with total intravenous anesthesia, which does not depend on ventilation, may be more appropriate.