Subject: Role of Impulse Oscillometry in Children with Airway
Narrowing After Bronchoscopic Stent Implantation, a Pilot Observational
Study
Tzung-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, Taiwan
2Division of Pediatric Pulmonology, China Medical University Children’s
Hospital, China Medical University, Taichung, Taiwan
3 Department of Pediatrics, School of Medicine, National Yang-Ming
University, Taipei, Taiwan
4 Department of Pediatrics, Taipei Veterans General Hospital, Taipei,
Taiwan
5 Department of Pediatrics, Tri-Service General Hospital, Taipei, Taiwan
* Correspondence:
Corresponding Author: Chieh-Ho Chen, Chien-Heng Lin and Wen-Jue Soong
pedlungcmu@gmail.com
Keywords: Impulse oscillometry, transbronchoscopic airway intervention,
stent, obstructive lung disease, peripheral airway resistance, pulmonary
function test
To 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.