Rapid Establishment of Tracheal Stenosis in Pigs Using Endotracheal Tube Cuff Overpressure and Electrocautery

ABSTRACT Background Central airway obstruction can be caused by cancer, tracheal intubation, or tuberculosis, among others. If surgery is contraindicated, bronchoscopic therapy may be performed. Bronchoscopic treatment for airway obstruction is continuously evolving. In particular, attempts to overcome the current shortcomings of airway stents (stent migration, mucostasis, and granulation tissue formation) are currently ongoing. To apply a new airway stent to humans, preclinical studies in an appropriate animal model is needed. Canine and porcine tracheas have been used as animal airway stenosis models. However, existing models take a long time to develop (3–8 weeks) and have a disadvantage that the mechanism of stenosis is different from that in humans. Purpose To establish a new and fast tracheal stenosis model in pigs using a combination of cuff overpressure intubation and electrocautery. Methods Fourteen pigs were divided into three groups: tracheal cautery (TC) group (n = 3), cuff overpressure intubation (COI) group (n = 3), and COI-TC combination group (n = 8). Cuff overpressure (200/400/500 mmHg) was applied using a 9-mm internal diameter endotracheal tube. Tracheal cautery (40/60 watts) was performed using a rigid bronchoscopic electrocoagulator. After intervention, the pigs were observed for 3 weeks and bronchoscopy was performed every 7 days. When the cross-sectional area decreased by > 50%, it was judged that tracheal stenosis was established. Results The time for tracheal stenosis was 14 days in the TC group and 7 days in the COI-TC combination group. In the COI group, no stenosis occurred. In the COI-TC group, electrocautery (40 watts) immediately after intubation for > 1 hour with a cuff pressure of 200 mmHg or more resulted in sufficient tracheal stenosis within 7 days. Moreover, the degree of tracheal stenosis increased in proportion to the cuff pressure and tracheal intubation time. Conclusions The combined use of cuff overpressure and electrocautery helped to establish tracheal stenosis in pigs rapidly. This animal model was technically simple and reproducible, and used a mechanism similar to that in human tracheal stenosis. It is expected to help develop new treatments for airway stenosis