Impulse oscillometry for evaluating pulmonary function in pediatric pectus deformities: a prospective controlled study.

UNLABELLED

Pectus deformities (PDs), including pectus excavatum and pectus carinatum, may affect pulmonary mechanics; however, spirometry often fails to detect subtle abnormalities. This study aimed to evaluate pulmonary function in children with PDs using both spirometry and impulse oscillometry (IOS). In this prospective cross-sectional study, 73 children with PDs and 80 age- and sex-matched healthy controls underwent spirometry and IOS testing. z-scores were calculated for all parameters using established reference equations. A possible restrictive ventilatory defect was defined as zFVC <  - 1.645 with normal or elevated zFEV/zFVC. Children with PDs had significantly lower zFVC and zFEV values and higher zAX and zX15 compared with controls (p < 0.001, p = 0.008, p < 0.001, and p = 0.033, respectively). No child exhibited an obstructive pattern, while 61.6% had a possible restrictive ventilatory defect. In multivariate analysis, lower zBMI (OR 0.494; 95% CI 0.286-0.855; p = 0.012) and higher zAX (OR 1.528; 95% CI 1.112-2.100; p = 0.009) independently predicted restriction. ROC analysis identified a zAX cutoff of ≥ 4.97 (AUC 0.671, sensitivity 75.8%, specificity 53.8%).

CONCLUSION

These findings highlight the added value of IOS in detecting respiratory impairment in PDs. The combined use of IOS and spirometry may enable earlier identification of functional limitation, and zAX may serve as a useful marker in clinical decision-making and follow-up planning for affected children.

WHAT IS KNOWN

• Pectus deformities (PDs) may impair pulmonary function, but spirometry often yields inconsistent results. • Impulse oscillometry is a sensitive, effort-independent tool for assessing respiratory mechanics.

WHAT IS NEW

• IOS parameters indicated increased peripheral pulmonary airway reactance (zX5) and zAX, suggesting altered respiratory mechanics, while revealing no evidence of any obstructive pattern on spirometry. • The combined use of IOS and spirometry may be a useful pulmonary function test in clinical decision-making and follow-up planning for children with PDs.