Occlusion pressure and breathing pattern in healthy children.

The breathing pattern was investigated in 62 children aged 4 to 16 years together with the mouth pressure generated 0.1 s after an occlusion at the endexpiratory level (P0.1). A group of 20 adults (18 to 32 years old) were tested in a similar way. The values of P0.1 obtained during room air breathing at rest in the children decreased with age as a power function P0.1 = 8.51 A-0.62 (where A is age in years), r = -0.74. Adult values of P0.1 were achieved at about 13 years. After O2 inhalation P0.1 decreased in children, but the changes in P0.1 were independent of age. Respiratory frequency decreased with age while inspiratory time (TI) increased, both reaching adult values at about 13 years. The ratio of TI over the total respiratory cycle duration did not change significantly with age in the entire population. The absolute value of tidal volume (VT) increased with age, but not when normalized for body weight (BW). The mean inspiratory flow (VT/TI) normalized for BW decreased with age in children as did P0.1. There was a significant relationship between P0.1 and VT/TI normalized for body weight (r = 0.63).