Spirometry in preschool children: time has come for new reference values

Area of Science:

• Pediatric Pulmonology
• Respiratory Physiology
• Diagnostic Spirometry

Background:

• Lung function tests are vital for diagnosing and monitoring childhood asthma.
• Existing reference values for lung function are outdated, based on older populations from decades ago.
• Accurate, current reference values are needed for proper clinical evaluation of children's lung health.

Purpose of the Study:

• To assess the validity of current lung function reference values in 6-year-old children.
• To evaluate the correlation between lung function parameters and Body Mass Index (BMI) in this age group.
• To determine the feasibility of standardized spirometry for early lung function assessment in preschoolers.

Main Methods:

• A cross-sectional study involving 518 children (mean age 6.0 years) undergoing spirometry before school enrollment.
• Measurements included forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximal expiratory flow (PEF), and maximal expiratory flow at 75%, 50%, and 25% of vital capacity (MEF75, MEF50, MEF25).
• Spirometry followed ATS/ERS criteria, with a focus on maneuvers where expiratory time (TE) exceeded 1 second.

Main Results:

• FEV1 and FVC values were comparable to existing reference values (101.0% in boys, 95.4% in girls).
• Maximal expiratory flow parameters (PEF, MEF50) were significantly lower than reference values (68.9% in boys, 75.9% in girls) when TE > 1 sec.
• No significant correlation was found between lung function parameters and BMI in this cohort.

Conclusions:

• Current reference values significantly overestimate maximal expiratory flow rates in preschool children using spirometry with TE > 1 sec.
• Increased BMI does not appear to impair forced expiratory flow rates in 6-year-old children.
• Implementing standardized spirometry in preschool children enables precise evaluation of individual lung function development.