TABLE 3.

COMMONS PRESCHOOL LUNG FUNCTION TECHNIQUES, CORRESPONDING MEASURES, AND ADVANTAGES/DISADVANTAGES OF PRESCHOOL LUNG FUNCTION TECHNIQUES

Technique	Measures	Advantages	Disadvantages
Spirometry	FVC, FEV0.5, FEV0.75, FEF25–75	Published guidelines	May be difficult to obtain technically acceptable data, particularly in youngest children
		Allows longitudinal assessment from infancy to adulthood
			Minimal between-occasion reproducibility data available
		Reference data
Interrupter resistance	Rint Rrs Xrs	Published guidelines	Assumes respiratory system a single compartment
Forced oscillation (FO)		Simple, noninvasive	May not be sensitive to small airway disease
		Quick Reference data available
Specific airway resistance	sRaw	Simple, quick	Expensive equipment
			Minimal reference data
Gas washout	LCI, MR	Simple, noninvasive	Minimal reference data
		May be sensitive to early airway disease	No published guidelines
			Expensive equipment
			No published data as to whether responsive to intervention

Definition of abbreviations: FEV_0.75 = forced expiratory volume at 0.75 seconds; FEF_25–75 = forced expiratory flows between 25 and 75% of FVC; FEV_0.5 = forced expiratory volume at 0.5 seconds; ; LCI = lung clearance index; MR = mixing ratio); Rint = interrupter resistance measure; Rrs = respiratory system resistance measured using forced oscillation; sRaw = plethysmographic specific airway resistance; Xrs = respiratory system reactance measured using forced oscillation.