Impulse oscillometry bronchodilator response in preschool children.

Area of Science:

• Pediatric Pulmonology
• Respiratory Physiology

Background:

• Spirometry for measuring bronchodilator response (BDR) is challenging in preschoolers.
• Impulse oscillometry (IOS) offers a promising alternative for assessing BDR in this age group.
• Standardization of BDR measurement using IOS in young children requires further investigation.

Purpose of the Study:

• To establish optimal thresholds for defining a positive BDR test using IOS in preschoolers with suspected asthma.
• To evaluate the utility of IOS as an alternative to spirometry for BDR assessment in young children.

Main Methods:

• Retrospective analysis of lung function data (IOS and spirometry) from children aged 3-6 years with suspected asthma.
• BDR was assessed pre- and post-bronchodilator administration.
• Defined positive spirometric BDR as a change in FEV1 ≥12% or ≥200 mL.
• Defined positive oscillometric BDR based on changes in R5, X5, and AX parameters.

Main Results:

• Of 72 patients, 36 met quality criteria for analysis.
• Spirometric BDR was positive in 19.4% of subjects, while oscillometric BDR was positive in 11.1%.
• A decrease in R5 of 25.7% and an increase in X5 of 25.7% demonstrated the best sensitivity and specificity for detecting spirometric BDR.

Conclusions:

• IOS is a valid and potentially superior method for measuring BDR in preschool children.
• Proposed diagnostic thresholds for IOS-based BDR are a 26% decrease in R5 and a 26% increase in X5.
• IOS should be considered the gold standard for BDR assessment in this pediatric population.