title: Alternative inert gas washout outcomes in patients with primary ciliary dyskinesia.
abstract: The lung clearance index (LCI) derived from a nitrogen multiple breath washout test (N2-MBW) is a promising tool to assess small airways disease in primary ciliary dyskinesia, but it is difficult to apply in routine clinical settings because of its long measuring time. In this study, we aimed to assess alternative indices derived from shorter washout protocols.49 patients with primary ciliary dyskinesia (mean age 14.7±6.6 years) and 37 controls (mean age 14.3±1.4 years) performed N2-MBW and double-tracer gas (DTG) single-breath washout tests. Global (LCI and moment ratio (M2/M0)), conductive (Scond) and acinar ventilation inhomogeneity (DTG Slope III (SIII-DTG)) were determined for each individual. The main outcomes were 1) the ability to detect abnormal lung function from washout indices (>1.64 z-scores) and 2) measurement duration.The prevalence of abnormal values for LCI2.5%was 37 out of 47 (79%), for LCI5%was 34 out of 47 (72%), for M2/M0was 34 out of 47 (72%), for Scondwas 36 out of 46 (78%) and for SIII-DTG was 12 out of 35 (34%). Mean±sd duration of measurement was 19.8±11.2 min for LCI2.5%, 10.8±4.6 min for LCI5%and 8.6±2.3 min for ScondCompared to standard LCI2.5%, ventilation inhomogeneity was detected by LCI5%, moment ratio and Scondwith comparable sensitivity while measurement duration was significantly shorter. Longitudinal studies will show which outcome is most suitable and practical in terms of sensitivity, duration and variability within the course of primary ciliary dyskinesia lung disease.
authors.affiliation: Paediatric Respiratory Medicine, Dept of Paediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland.|Dept of Paediatric Pulmonology, University Children's Hospital Basel (UKBB), Basel, Switzerland.|Contributed equally as first authors.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Nyilas
authors.affiliation: Dept of Paediatric Pulmonology, University Children's Hospital of Ruhr University Bochum at St. Josef-Hospital, Bochum, Germany.|Contributed equally as first authors.
authors.forename: Anne
authors.initials: A
authors.lastname: Schlegtendal
authors.affiliation: Paediatric Respiratory Medicine, Dept of Paediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland.|Division of Respiratory Medicine, University Children's Hospital Zurich, Zurich, Switzerland.
authors.forename: Florian
authors.initials: F
authors.lastname: Singer
authors.affiliation: Paediatric Respiratory Medicine, Dept of Paediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland.|Institute for Social and Preventive Medicine, University of Bern, Bern, Switzerland.
authors.forename: Myrofora
authors.initials: M
authors.lastname: Goutaki
authors.affiliation: Institute for Social and Preventive Medicine, University of Bern, Bern, Switzerland.
authors.forename: Claudia E
authors.initials: CE
authors.lastname: Kuehni
authors.affiliation: Paediatric Respiratory Medicine, Dept of Paediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland.
authors.forename: Carmen
authors.initials: C
authors.lastname: Casaulta
authors.affiliation: Paediatric Respiratory Medicine, Dept of Paediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland.|Dept of Paediatric Pulmonology, University Children's Hospital Basel (UKBB), Basel, Switzerland.|Contributed equally as senior authors.
authors.forename: Philipp
authors.initials: P
authors.lastname: Latzin
authors.affiliation: Dept of Paediatric Pulmonology, University Children's Hospital of Ruhr University Bochum at St. Josef-Hospital, Bochum, Germany Cordula.Koerner-Rettberg@rub.de.|Contributed equally as senior authors.
authors.forename: Cordula
authors.initials: C
authors.lastname: Koerner-Rettberg
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D005858:Germany; D006371:Helium; D006801:Humans; D007619:Kartagener Syndrome / Q000175:diagnosis* / Q000503:physiopathology*; D016014:Linear Models; D008297:Male; D012123:Pulmonary Ventilation; D012119:Respiration; D013147:Spirometry; D013459:Sulfur Hexafluoride; D013557:Switzerland; D055815:Young Adult
chemical_list: D006371:Helium; D013459:Sulfur Hexafluoride