RT Journal
A1 Barbi E, Neri E, Ventura A
T1 Nomina sunt consequentia rerum: Time for a change in the definition of bronchiolitis?
JF Archives of Pediatrics & Adolescent Medicine
JO Archives of Pediatrics & Adolescent Medicine
YR 2004
FD April 1
VO 158
IS 4
SP 403
OP 403
DO 10.1001/archpedi.158.4.403-a
UL http://dx.doi.org/10.1001/archpedi.158.4.403-a
AB 
The newborn's lungs move through important changes from birth to 2 years of age. The proper fetal period of lung development, with the end being the saccular stage, is close to 6 months of age, and the alveolar-arterial ratio of 20:1 in the newborn changes to 12:1 at 2 years of age, which is closer to the ratio for older children of 10:1.