Control of Breathing in Children with Interstitial Lung Disease

Abstract

Control of breathing at rest was studied in 14 children (4-16 years old) with interstitial lung disease (ILD). Four of them were tested several times. Breathing pattern and the mouth occlusion pressure (P0.1) were measured. Results in ILD children were compared to values in healthy children previously reported. Respiratory frequency and minute ventilation were increased (P less than 0.02). Inspiratory time (TI) was shortened (P less than 0.001), the shortening in TI being significantly related to the increase in lung elastance (EL). The ratio of TI to the total duration of the respiratory cycle (TI/TTOT) was lowered (P less than 0.01). Tidal volume (VT) both in ml and normalized for body weight (BW) was normal. P0.1 was higher than predicted. The increase in P0.1 was significantly related to change in arterial O2 pressure (PaO2) which was reduced in 10 cases. There was a significant relationship between the increase in P0.1 and in EL. The increase in mean inspiratory flow (VTBW/TI) was related to the increase in EL. But VTBW/TI was not increased as much as P0.1. Consequently the effective inspiratory impedance was enhanced. This high effective inspiratory impedance was related to the increased lung elastance.