The impact of adenoid hypertrophy on pulmonary functions measured using impulse oscillometry in preschool-age children.

This study shows that IOS is a useful method for demonstrating subclinical bronchial obstruction in preschool-age children with AH with greater pulmonary impedance (resistance and reactance). Pulmonary impedance decreased 3 months after adenoidectomy, but remained higher than in the HCs. The IOS parameter of X20 may be predictive of adenoidectomy. This study evaluated the pulmonary functions of children with adenoid hypertrophy (AH) using impulse oscillometry (IOS) and the association with the scale of AH. Pulmonary functions were analyzed using IOS. The main IOS parameters include resistances (zR5 and zR20), reactance (zX5 and zX20), R5-20 (resistance at 5 Hz minus resistance at 20 Hz), resonant frequency (Fres), and AX. Fres is the point at which reactance is zero and is measured in Hz (1/s). The Reactance Area (AX - "Goldman Triangle") represents the integrated low-frequency respiratory reactance magnitude between 5 Hz and Fres. Faster frequencies of R (~ 20 Hz) reflect larger airways, regarded as resistance around the central airways. Lower frequencies of R (~ 5 Hz) providing information around the entire (small and large) airways. Peripheral (small) airway resistance is defined by R5-20. IOS parameters of zR5, zX20, Fres, and AX differed among AH grades I-IV and compared to the HCs (p < 0.001 for all).