Lung Oscillometry: New hope in asthma diagnosis in children

Abstract

Asthma is the most common chronic respiratory disease in children, with a rising prevalence in Bangladesh. The diagnosis of asthma in young children is always challenging. Spirometry, the gold standard test for asthma is suitable only for older children as its applicability is limited in young children due to the need for active cooperation and forced respiratory manoeuvres. Lung oscillometry, is an emerging non-invasive method that evaluates the mechanical properties of the respiratory system during tidal breathing. It is a simple, non-invasive test where a pressure wave generated by external source is given to the airway through the mouth and pressure-flow relationship is analysed to calculate impedance of the respiratory system. Oscillometry is particularly advantageous in children above 3 years of age and in patients unable to perform spirometry, as it requires minimal cooperation and tidal breathing. Key indices such as resistance (Rrs), reactance (Xrs), resonant frequency (Fres), and reactance area (AX) provide information on subtle changes of small airway dysfunction and bronchodilator reversibility. Despite its strengths, challenges remain, including lack of standardized reference values, inter-device variability and the need for validated cut-off thresholds for bronchodilator responsiveness. Further research is required to establish regional normative data, standardize equipment and interpretation protocols. This review summarizes the principles, historical development, procedure, measured parameters, quality control criteria, reference values, bronchodilator response and clinical utility of lung oscillometry in paediatric practice.

DS (Child) H J 2025; 41(1): 39-42