Gas exchanges in children with cystic fibrosis or primary ciliary dyskinesia: A retrospective study

International audience; Primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) both entail bronchiectasis and pulmonary impairment as measured using spirometry, during childhood. We aimed at looking whether blood gas exchanges progressed differently between CF and PCD children in a retrospective study of repeated measurements. Comparisons between groups (Wilcoxon-Mann-Whitney and Chi-squared tests) and a mixed linear model, adjusted for age, evaluated associations between diseases and PaO2, PaCO2, or PaO2-PaCO2 ratio.Among 42 PCD and 73 CF children, 62% and 59% had respectively bronchiectasis (P = 0.75). Spirometry and blood gases were similar at inclusion (PaO2 median [IQR] PCD −1.80 [−3.40; −0.40]; CF −1.80 [−4.20; 0.60] z-scores; P = 0.72). PaO2 and PaO2-PaCO2 ratio similarly and significantly decreased with age in both groups (P