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Single and multiple breath nitrogen washout compared with the methacholine test in patients with suspected asthma and normal spirometry.
Siebeneichler, Aline Stalder; Schumann, Desiree M; Karakioulaki, Meropi; Brachsler, Nora; Darie, Andrei M; Grize, Leticia; Heck, Thiago G; Tamm, Michael; Latzin, Philipp; Stolz, Daiana.
Affiliation
  • Siebeneichler AS; Clinic of Pneumology, University Hospital Basel, Basel, Switzerland.
  • Schumann DM; Clinic of Pneumology, University Hospital Basel, Basel, Switzerland.
  • Karakioulaki M; Clinic of Pneumology, University Hospital Basel, Basel, Switzerland.
  • Brachsler N; Clinic of Pneumology, University Hospital Basel, Basel, Switzerland.
  • Darie AM; Clinic of Pneumology, University Hospital Basel, Basel, Switzerland.
  • Grize L; Clinic of Pneumology, University Hospital Basel, Basel, Switzerland.
  • Heck TG; UNIJUI, Ijui, RS, Brazil.
  • Tamm M; Clinic of Pneumology, University Hospital Basel, Basel, Switzerland.
  • Latzin P; Inselspital, Kinderklinik, University of Bern, Bern, Switzerland.
  • Stolz D; Clinic of Pneumology, University Hospital Basel, Basel, Switzerland daiana.stolz@uniklinik-freiburg.de.
BMJ Open Respir Res ; 11(1)2024 May 02.
Article in En | MEDLINE | ID: mdl-38697675
ABSTRACT

BACKGROUND:

Methods used to assess ventilation heterogeneity through inert gas washout have been standardised and showed high sensitivity in diagnosing many respiratory diseases. We hypothesised that nitrogen single or multiple breath washout tests, respectively nitrogen single breath washout (N2SBW) and nitrogen multiple breath washout (N2MBW), may be pathological in patients with clinical suspicion of asthma but normal spirometry. Our aim was to assess whether N2SBW and N2MBW are associated with methacholine challenge test (MCT) results in this population. We also postulated that an alteration in SIII at N2SBW could be detected before the 20% fall of forced expiratory volume in the first second (FEV1) in MCT. STUDY DESIGN AND

METHODS:

This prospective, observational, single-centre study included patients with suspicion of asthma with normal spirometry. Patients completed questionnaires on symptoms and health-related quality-of-life and underwent the following lung function tests N2SBW (SIII), N2MBW (Lung clearance index (LCI), Scond, Sacin), MCT (FEV1 and sGeff) as well as N2SBW between each methacholine dose.

RESULTS:

182 patients were screened and 106 were included in the study, with mean age of 41.8±14 years. The majority were never-smokers (58%) and women (61%). MCT was abnormal in 48% of participants, N2SBW was pathological in 10.6% at baseline and N2MBW abnormality ranged widely (LCI 81%, Scond 18%, Sacin 43%). The dose response rate of the MCT showed weak to moderate correlation with the subsequent N2SBW measurements during the provocation phases (ρ 0.34-0.50) but no correlation with N2MBW.

CONCLUSIONS:

Both MCT and N2 washout tests are frequently pathological in patients with suspicion of asthma with normal spirometry. The weak association and lack of concordance across the tests highlight that they reflect different but not interchangeable pathological pathways of the disease.
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Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Asthma / Spirometry / Breath Tests / Bronchial Provocation Tests / Methacholine Chloride / Nitrogen Limits: Adult / Female / Humans / Male / Middle aged Language: En Journal: BMJ Open Respir Res Year: 2024 Document type: Article Affiliation country: Switzerland

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Asthma / Spirometry / Breath Tests / Bronchial Provocation Tests / Methacholine Chloride / Nitrogen Limits: Adult / Female / Humans / Male / Middle aged Language: En Journal: BMJ Open Respir Res Year: 2024 Document type: Article Affiliation country: Switzerland
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