title: A new double-tracer gas single-breath washout to assess early cystic fibrosis lung disease.
abstract: In cystic fibrosis (CF), tests for ventilation inhomogeneity are sensitive but not established for clinical routine. We assessed feasibility of a new double-tracer gas single-breath washout (SBW) in school-aged children with CF and control subjects, and compared SBW between groups and with multiple-breath nitrogen washout (MBNW). Three SBW and MBNW were performed in 118 children (66 with CF) using a side-stream ultrasonic flowmeter setup. The double-tracer gas containing 5% sulfur hexafluoride and 26.3% helium was applied during one tidal breath. Outcomes were SBW phase III slope (SIII(DTG)), MBNW-derived lung clearance index (LCI), and indices of acinar (S(acin)) and conductive (S(cond)) ventilation inhomogeneity. SBW took significantly less time to perform than MBNW. SBW and MBNW were feasible in 109 (92.4%) and 98 (83.0%) children, respectively. SIII(DTG) differed between children with CF and controls, mean±sd was -456.7±492.8 and -88.4±129.1 mg·mol·L(-1), respectively. Abnormal SIII(DTG) was present in 36 (59%) children with CF. SIII(DTG) was associated with LCI (r= -0.58) and S(acin) (r= -0.58), but not with S(cond). In CF, steeply sloping SIII(DTG) potentially reflects ventilation inhomogeneity near the acinus entrance. This tidal SBW is a promising test to assess ventilation inhomogeneity in an easy and fast way.
authors.affiliation: Division of Respiratory Medicine, Dept. of Paediatrics, University Hospital of Bern, Bern, Switzerland.
authors.forename: Florian
authors.initials: F
authors.lastname: Singer
authors.forename: Georgette
authors.initials: G
authors.lastname: Stern
authors.forename: Cindy
authors.initials: C
authors.lastname: Thamrin
authors.forename: Chiara
authors.initials: C
authors.lastname: Abbas
authors.forename: Carmen
authors.initials: C
authors.lastname: Casaulta
authors.forename: Urs
authors.initials: U
authors.lastname: Frey
authors.forename: Philipp
authors.initials: P
authors.lastname: Latzin
mesh_terms: D000293:Adolescent; D001944:Breath Tests / Q000295:instrumentation / Q000379:methods*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000175:diagnosis*; D005240:Feasibility Studies; D005260:Female; D045268:Flowmeters; D005541:Forced Expiratory Volume; D005740:Gases; D006801:Humans; D008297:Male; D009584:Nitrogen / Q000378:metabolism; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012123:Pulmonary Ventilation / Q000502:physiology*; D015203:Reproducibility of Results; D013147:Spirometry / Q000379:methods; D013459:Sulfur Hexafluoride / Q000494:pharmacology; D013990:Tidal Volume
chemical_list: D005740:Gases; D009584:Nitrogen; D013459:Sulfur Hexafluoride