Presented at the Neonatal Society 2002 Spring Meeting.
Hoo A-F1, Dezateux C2, Henschen M1, Costeloe K3, Stocks J1
1 Portex Respiratory Unit, London, UK
2 Centre of Paediatric Epidemiology and Biostatistics, Institute of Child Health & GOS Hospital NHS Trust, London, UK
3 Barts & the London School of Medicine & Dentistry, Homerton Hospital, London, UK
Background: Factors associated with preterm delivery may influence subsequent lung growth and development.
Aim: To compare airway function at one year of age in preterm infants without clinical neonatal respiratory disease with that measured shortly after birth.
Methods: Infants born <=36 w gestational age (GA) were eligible if they had required no neonatal ventilatory support and were otherwise healthy. Paired measurements of maximal expiratory flow at functional residual capacity (V’maxFRC), which is a measure of peripheral airway function, were obtained ~ 3w after birth in 24 preterm infants (42% male), mean (SD) GA 33.2 (2.2) w, and were repeated at a mean (SD) corrected postnatal age of 57.0 (12.2) w. V’maxFRC was expressed as Z-scores using sex-specific prediction equations from recently collated reference data (1).
Results: V’maxFRC was within the normal range for all infants shortly after birth [mean (SD) Z-score: -0.06 (0.92)]. By one year of age, there had been a significant reduction in Z-scores [mean (95% CI), second-first test: -1.94 (-2.27, -1.60)]. V’maxFRC Z-scores at 3 w were highly correlated with those at 1 year of age (r² = 0.64), suggesting considerable “tracking” of airway function during the first year.
Conclusion: Despite ‘normal’ values shortly after birth, V’maxFRC was significantly reduced in preterm infants by one year of age. These findings suggest that even in the absence of any neonatal disease or ventilatory intervention, preterm delivery per se may be associated with impaired airway development during early life.
Ackknowledgements: Funded by the Foundation for the Study of Infant Deaths, the Dunhill Medical Trust, the Deutsche Forschungsgemeinschaft and Portex Plc. Research at the Institute of Child Health and Great Ormond Street Hospital for Children NHS Trust benefits from R&D funding received from the NHS Executive.
References
1. Hoo A-F et al. Sex-specific cross-sectional reference standards for V’maxFRC in infancy: a multicenter collaborative study. Am J Respir Crit Care Med 2002. In press.