Subject: Role of Impulse Oscillometry in Children with Airway Narrowing After Bronchoscopic Stent Implantation, a Pilot Observational StudyTzung-Lin Ou1, Chieh-Ho Chen2*, Chien-Heng Lin2* and Wen-Jue Soong 2,3,4,5*1Department of Medicine, College of Medicine, China Medical University, Taichung, Taiwan2Division of Pediatric Pulmonology, China Medical University Children’s Hospital, China Medical University, Taichung, Taiwan3 Department of Pediatrics, School of Medicine, National Yang-Ming University, Taipei, Taiwan4 Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan5 Department of Pediatrics, Tri-Service General Hospital, Taipei, Taiwan* Correspondence:Corresponding Author: Chieh-Ho Chen, Chien-Heng Lin and Wen-Jue [email protected]: Impulse oscillometry, transbronchoscopic airway intervention, stent, obstructive lung disease, peripheral airway resistance, pulmonary function testTo the Editor,We would like to address the critical issue of congenital airway anomalies, encompassing tracheal stenosis, tracheomalacia, and tracheo-bronchomalacia, which pose life-threatening challenges. Patients afflicted with these conditions frequently exhibit respiratory distress, such as tachypnea, dyspnea, chest tightness, chronic cough, exercise intolerance, and audible breathing sounds. The risk of recurring pulmonary infections is associated with inadequate airway clearance, culminating in irreversible lung damage over time.Bronchoscopic airway stent placement emerges as an efficacious strategy for alleviating tracheo-bronchial obstructions. It demonstrates notable success in mitigating breathlessness, elevating quality of life, and enhancing survival rates, especially among adults with malignancies. However, the extension of this technique to pediatric populations remains underexplored, primarily due to concerns regarding potential complications, including hypoxia, laryngospasm, hemorrhage, and air-leak syndromes. Despite its clinical safety, the absence of established consensus or guidelines for bronchoscopy and airway stent implantation in infants and children persists (1).Nevertheless, evaluation of pulmonary function after airway stent implantation by spirometry might be challenging in pediatric population due to weak respiratory efforts, inadequate cooperation, and poor comprehension. This is where Impulse Oscillometry (IOS) comes into play. Grounded in the forced oscillation technique, IOS passively assesses airway resistance and alveolar reactance during tidal breathing. IOS is able to differentiate resistance of peripheral (small) airways from central (large) airways, thus aiding treatment planning for obstructive lung diseases. It encompasses parameters like respiratory impedance (Z), respiratory resistance (R), and respiratory reactance (X), which together provide a comprehensive analysis of airway function, assisting in the assessment of obstructive and restrictive lung diseases.
