Florian Singer1, Chiara Abbas2, Sophie Yammine3, Carmen Casaulta2, Urs Frey4, Philipp Latzin5. 1. University Children's Hospital Zurich, Zurich; University Children's Hospital Bern, Bern. 2. University Children's Hospital Bern, Bern. 3. University Children's Hospital Bern, Bern; University Children's Hospital Basel, Basel, Switzerland. 4. University Children's Hospital Zurich, Zurich; University Children's Hospital Basel, Basel, Switzerland. 5. University Children's Hospital Bern, Bern; University Children's Hospital Basel, Basel, Switzerland. Electronic address: philipp.latzin@ukbb.ch.
Abstract
BACKGROUND: Small airways disease is a hallmark in adults with persistent asthma, but little is known about small airways function in children with mild asthma and normal spirometry. We assessed ventilation heterogeneity, a marker of small airways function, with an easy tidal breath single-breath washout (SBW) technique in school-aged children with mild asthma and normal FEV1 and healthy age-matched control subjects. METHODS: The primary outcome was the double-tracer gas phase III slope (SDTG), an index of ventilation heterogeneity in acinar airways derived from the tidal double-tracer gas SBW test. The second outcome was the nitrogen phase III slope (SN2), an index of global ventilation heterogeneity derived from the tidal nitrogen SBW test using pure oxygen. Triplicate SBW and spirometry tests were performed in healthy children (n=35) and children with asthma (n=31) at baseline and in children with asthma after bronchodilation. RESULTS: Acinar (SDTG) but not global (SN2) ventilation heterogeneity was significantly increased in asthma despite normal FEV1. Of the 31 children with asthma, abnormal results were found for SDTG (≤-2 z scores) in 11; forced expiratory flow, midexpiratory phase (FEF25%-75%) in three; and FEV1 in zero. After bronchodilation, SDTG, SN2, FEF25%-75%, and FEV1 significantly changed (mean [95% CI] change from baseline, 36% [15%-56%], 38% [18%-58%], 17% [9-25%], and 6% [3%-9%], respectively). CONCLUSIONS: Abnormal acinar ventilation heterogeneity in one-third of the children suggests that small airways disease may be present despite rare and mild asthma symptoms and normal spirometry. The easy tidal SBW technique has considerable potential as a clinical and research outcome in children with asthma.
BACKGROUND: Small airways disease is a hallmark in adults with persistent asthma, but little is known about small airways function in children with mild asthma and normal spirometry. We assessed ventilation heterogeneity, a marker of small airways function, with an easy tidal breath single-breath washout (SBW) technique in school-aged children with mild asthma and normal FEV1 and healthy age-matched control subjects. METHODS: The primary outcome was the double-tracer gas phase III slope (SDTG), an index of ventilation heterogeneity in acinar airways derived from the tidal double-tracer gas SBW test. The second outcome was the nitrogen phase III slope (SN2), an index of global ventilation heterogeneity derived from the tidal nitrogen SBW test using pure oxygen. Triplicate SBW and spirometry tests were performed in healthy children (n=35) and children with asthma (n=31) at baseline and in children with asthma after bronchodilation. RESULTS: Acinar (SDTG) but not global (SN2) ventilation heterogeneity was significantly increased in asthma despite normal FEV1. Of the 31 children with asthma, abnormal results were found for SDTG (≤-2 z scores) in 11; forced expiratory flow, midexpiratory phase (FEF25%-75%) in three; and FEV1 in zero. After bronchodilation, SDTG, SN2, FEF25%-75%, and FEV1 significantly changed (mean [95% CI] change from baseline, 36% [15%-56%], 38% [18%-58%], 17% [9-25%], and 6% [3%-9%], respectively). CONCLUSIONS: Abnormal acinar ventilation heterogeneity in one-third of the children suggests that small airways disease may be present despite rare and mild asthma symptoms and normal spirometry. The easy tidal SBW technique has considerable potential as a clinical and research outcome in children with asthma.
Authors: Johannes Port; Ziran Tao; Annika Junger; Christoph Joppek; Philipp Tempel; Kim Husemann; Florian Singer; Philipp Latzin; Sophie Yammine; Joachim H Nagel; Martin Kohlhäufl Journal: Med Biol Eng Comput Date: 2017-03-29 Impact factor: 2.602
Authors: F Braido; N Scichilone; F Lavorini; O S Usmani; L Dubuske; L P Boulet; R Mosges; C Nunes; M Sanchez-Borges; I J Ansotegui; M Ebisawa; F Levi-Schaffer; L J Rosenwasser; J Bousquet; T Zuberbier; G Walter Canonica; A Cruz; A Yanez; A Yorgancioglu; D Deleanu; G Rodrigo; J Berstein; K Ohta; P Vichyanond; R Pawankar; S N Gonzalez-Diaz; S Nakajima; T Slavyanskaya; A Fink-Wagner; C Baez Loyola; D Ryan; G Passalacqua; J Celedon; J C Ivancevich; K Dobashi; M Zernotti; M Akdis; S Benjaponpitak; S Bonini; W Burks; L Caraballo; Z Awad El-Sayed; S Fineman; P Greenberger; E Hossny; J A Ortega-Martell; H Saito; M Tang; L Zhang Journal: World Allergy Organ J Date: 2016-10-28 Impact factor: 4.084
Authors: F Braido; N Scichilone; F Lavorini; O S Usmani; L Dubuske; L P Boulet; R Mosges; C Nunes; M Sánchez-Borges; I J Ansotegui; M Ebisawa; F Levi-Schaffer; L J Rosenwasser; J Bousquet; T Zuberbier; G Walter Canonica Journal: Asthma Res Pract Date: 2016-10-28
Authors: Lies Lahousse; Thomas Bahmer; Sara Cuevas-Ocaña; Pauline Flajolet; Alexander G Mathioudakis; Melissa McDonnell; Lena Uller; Florence Schleich; Sergio Dortas Junior; Marco Idzko; Dave Singh; Fabio L M Ricciardolo; Ian M Adcock; Omar Usmani; Antonio Spanevello; Sara J Bonvini Journal: ERJ Open Res Date: 2020-02-17