Normative Data of Infant Pulmonary Function Testing: A Prospective Birth Cohort Study from India

Area of Science:

• Pediatric Pulmonology
• Neonatal Physiology
• Respiratory Medicine

Background:

• Establishing normal reference ranges for infant pulmonary function tests (IPFT) is essential for diagnosing respiratory conditions in neonates and young children.
• Previous studies may not adequately represent the diverse Indian pediatric population.

Purpose of the Study:

• To develop a normal reference range of infant pulmonary function test (IPFT) indices specifically for Indian children.
• To provide normative data for evaluating lung function in healthy neonates and children up to 36 months of age in India.

Main Methods:

• A prospective birth cohort study was conducted over five years in a tertiary-care Indian institute.
• Infant pulmonary function tests (IPFT) using tidal breathing flow-volume loop (TBFVL), rapid thoracoabdominal compression (RTC), and raised volume RTC (RVRTC) were performed at baseline and every six months until 36 months of age.
• 310 newborns were enrolled, with 281 completing the 36-month follow-up.

Main Results:

• Tidal volume per unit body weight (VT/kg) significantly increased from birth to 36 months.
• The peak expiratory flow rate to expiratory time ratio (tPTEF/tE) initially decreased and then returned to baseline by 36 months.
• No significant changes were observed in RTC indices, while the FEV0.5/FVC ratio in RVRTC significantly decreased over the study period.

Conclusions:

• Normal values for TBFVL, RTC, and RVRTC indices have been established for Indian neonates and children up to 36 months.
• These findings provide valuable normative data for the assessment of infant pulmonary function in the Indian context.
• The study highlights age-related changes in specific IPFT indices during early childhood.