Randomized Cross-Over Analysis of the Influence of Nitrogen Multiple Breath Washout on Spirometry in Monitoring Lung Function in Patients With Cystic Fibrosis and Primary Ciliary Dyskinesia

BACKGROUND: When monitoring lung function in patients with Cystic Fibrosis (pwCF) and Primary Ciliary Dyskinesia (pwPCD), nitrogen multiple breath washout (N(2)MBW) is usually performed before spirometry to prevent forced expiratory maneuvers from altering N(2)MBW results. The N(2)MBW may affect spirometry if cooperation decreases after a long period of examination or due to prolonged oxygen inhalation. The equivalence of these concepts has never been investigated in a randomized cross-over trial. We hypothesized that the order of pulmonary function tests (PFTs) would not influence the z-score FEV(1). METHODS: A total of 47 clinically stable outpatients (36 pwCF, 11 pwPCD; 16.7 ± 8.1 years) were randomized into two groups. Each patient underwent N(2)MBW and spirometry at two consecutive visits (median interval 104 days): Group I: Spirometry followed by N(2)MBW (A), reversed order at the second visit (B), Group II reversed (B

• Schoop, A. C.
• Denz, R.
• Maier, C.
• Brinkmann, F.
• Lücke, T.
• Schlegtendal, A.