Reference values of impulse oscillometry (IOS) for healthy Chinese children aged 4–17 years

Respiratory Research

Table 3 Pearson’s correlation for resistance at 5 Hz, at 20 Hz, at 5 Hz, impedance at 5 Hz, resonant frequency, and reactance curve area below zero for boys and girls

IOS Parameters	Age		Height		Weight
	r	p	r	p	r	p
Boys
R₅, kPa/L/s	− 0.671	< 0.001	− 0.689	< 0.001	− 0.572	< 0.001
R₂₀, kPa/L/s	− 0.585	< 0.001	− 0.602	< 0.001	− 0.506	< 0.001
X₅, kPa/L/s	0.547	< 0.001	0.558	< 0.001	0.465	< 0.001
Z₅, kPa/L/s	− 0.685	< 0.001	− 0.707	< 0.001	− 0.583	< 0.001
Fres, Hz	− 0.335	< 0.001	− 0.352	< 0.001	− 0.305	< 0.001
R₅–R₂₀, kPa/L/s	− 0.522	< 0.001	− 0.517	< 0.001	− 0.422	< 0.001
Girls
R₅, kPa/L/s	− 0.637	< 0.001	− 0.664	< 0.001	− 0.591	< 0.001
R₂₀, kPa/L/s	− 0.536	< 0.001	− 0.552	< 0.001	− 0.508	< 0.001
X₅, kPa/L/s	0.516	< 0.001	0.533	< 0.001	0.492	< 0.001
Z₅, kPa/L/s	− 0.654	< 0.001	− 0.684	< 0.001	− 0.609	< 0.001
Fres, Hz	− 0.397	< 0.001	− 0.430	< 0.001	− 0.376	< 0.001
R₅–R₂₀, kPa/L/s	− 0.505	< 0.001	− 0.511	< 0.001	− 0.419	< 0.001

R₅ = resistance at 5 Hz, R₂₀ = resistance at 20 Hz, X₅ = reactance at 5 Hz, Fres = resonant frequency, Z₅ = impedance at 5 Hz, R₅–R₂₀ = fall in resistance between R₅ and R₂₀

ISSN: 1465-993X