Physiologic growth and development of the lung during the first year of life

Am Rev Respir Dis. 1986 Sep;134(3):513-9. doi: 10.1164/arrd.1986.134.3.513.


Pulmonary function tests were performed on a total of 125 healthy infants younger than 25 postconception (pc) months of age. Maximal expiratory flow at functional residual capacity (VmaxFRC) was measured from partial expiratory flow-volume curves, and functional residual capacity (FRC) was measured by the helium dilution technique. There was a highly significant (p less than 0.01) linear regression for both VmaxFRC and FRC with increasing body length. The highest size-corrected flows (VmaxFRC/FRC) were obtained in the healthy premature (2.7 FRC/s, n = 6) and full-term (2.5 FRC/s, n = 5) infants, and there was a relatively constant value between 13 and 25 pc months of age (1.2 FRC/s), which was similar to those reported in older children and adults. In an age-matched group of infants 10 to 16 pc months of age, females had both higher absolute flows (126 versus 102 ml/s, p less than 0.03) and size-corrected flows (1.4 versus 1.0 FRC/s, p less than 0.001) than did males. These physiologic data support the concepts that neonates have proportionately larger airways relative to their lung volume at FRC, infants have size-corrected flows similar to those in older children and adults, and female infants have proportionately larger airways relative to their lung size than do male infants.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Chloral Hydrate / pharmacology
  • Female
  • Functional Residual Capacity
  • Humans
  • Infant
  • Infant, Newborn
  • Lung / growth & development*
  • Lung / physiology
  • Male
  • Peak Expiratory Flow Rate
  • Pulmonary Ventilation*
  • Respiration / drug effects
  • Tidal Volume


  • Chloral Hydrate