Feasibility and Mortality of Airway Balloon Dilation in a Live Rabbit Model

Abstract

Endoscopic balloon dilation is commonly performed in children with airway stenosis, but guidelines are needed for selecting safe and effective balloon inflation parameters. To determine the feasibility and safety of airway balloon dilation in live rabbits using a range of balloon diameters and pressures. Prospective animal study using 32 adult New Zealand white rabbits with 1-week follow-up performed at an academic animal research facility. Rabbits underwent endoscopic laryngeal balloon dilation with diameters ranging from 6 to 10 mm and pressures of 5 to 15 atm. Rabbits were observed for intraoperative complications and postoperative morbidity. All rabbit airways were sized to a 4-0 endotracheal tube (5.4-mm outer diameter). Balloon dilation was performed safely with no intraoperative complications in 25 of 30 cases. One rabbit developed transient cyanosis during balloon inflation. Three rabbits died while undergoing dilation with 10-mm balloons, and another rabbit developed respiratory failure shortly after the procedure. All rabbits that died perioperatively lacked endoscopic evidence of airway obstruction or gross trauma. Four rabbits developed postoperative feeding difficulties that did not correlate with balloon diameter or inflation pressure. Endoscopic balloon dilation is generally well tolerated in New Zealand white rabbits. Intraoperative mortality from cardiopulmonary arrest reaches 50% when the balloon diameter exceeds the airway diameter by 4.6 mm. Postoperative feeding difficulties may occur with any balloon diameter or inflation pressure. Additional animal studies are necessary to determine the short- and long-term histologic effects of balloon dilation on the airway.