Specific airway resistance from the perinatal period into adulthood. Alterations in childhood pulmonary disease.

Airway resistance and lung volume were measured by a modification of the 
plethysmographic method of Briscoe and DuBois (1) to calculate specific airway 
resistance (SRaw) on 263 control subjects ranging in age from the 
newborn to 54 years. the mean SRaw was lowest in the 
newborn period and increased rapidly to adult levels during the first 
years of life. In each age group, the mean SRaw was 
lower for females than it was for males. No control subject 
had an SRaw greater than 8 sec cm H2O. A decrease 
in mean SRaw from 4.2 sec cm H2O for females 5 
to 9 years of age to 3.5 sec cm H2O for 
those over 18 years of age paralleled sexual maturation, but similar 
changes were not observed in the males. A direct correlation of 
SRaw with clinical observations was found in young patients with various 
degrees of pulmonary involvement because of cystic fibrosis. 