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

To apply a new airway treatment to humans, preclinical studies in an appropriate animal model is needed. Canine, porcine and leporine tracheas have been employed as animal airway stenosis models using various methods such as chemical caustic agents, laser, and electrocautery. However, existing models take a long time to develop (3-8 weeks) and the mechanism of stenosis is different from that in humans. The aim of the present study was to establish a new and fast tracheal stenosis model in pigs using a combination of cuff overpressure intubation (COI) and electrocautery. Fourteen pigs were divided into three groups: tracheal cautery (TC) group (n=3), COI group (n=3), and COI-TC combination group (n=8). Cuff overpressure (200/400/500 mmHg) was applied using a 9-mm 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 confirmed that tracheal stenosis was established. 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 h 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. The combined use of cuff overpressure and electrocautery helped to establish tracheal stenosis in pigs rapidly.