![]() Targets based on measured weight may disproportionally influence under-weight or over-weight subjects. However, this range may not be representative of subjects’ ‘normal’ V T and may force subjects to breathe outside their physiological range. A V T range of 10–15 ml/kg, based on measured weight, has been adopted as the default breathing range for the Exhalyzer D, a commonly used nitrogen multiple breath washout (N 2MBW) device. The 2013 European Respiratory Society/American Thoracic Society consensus statement for the MBW test provided general recommendations on test procedure but only broadly outline quality criteria for normal tidal breathing pattern. The MBW test does not require specific breathing maneuvers, thus there is growing interest in the use of MBW to monitor disease progression and treatment efficacy in children with lung disease.įor the MBW test to accurately reflect a subject’s gas mixing within the lungs, the breathing pattern should be representative of physiologically appropriate tidal volumes (V T) and respiratory rate (RR). The lung clearance index (LCI), measured by multiple breath washout (MBW), reflects global ventilation inhomogeneity and is a sensitive marker of early obstructive airway disease. Data requests can be made to the REB Chair Elizabeth Stephenson The author(s) received no specific funding for this work.Ĭompeting interests: The authors have declared that no competing interests exist. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: Data underlying the multi-center study cannot be made publicly available due to ethical restrictions imposed by the ethical review board, as participant consent did not include provisions for data sharing outside of the institutions. ![]() Received: MaAccepted: JPublished: July 3, 2019Ĭopyright: © 2019 Ratjen et al. PLoS ONE 14(7):Įditor: Jakob Usemann, UKBB Universitats-Kinderspital, SWITZERLAND (2019) Effect of changes in tidal volume on multiple breath washout outcomes. If subjects breathe naturally and are not instructed to use specific targets, the range of V T is within physiologically appropriate limits and normal variations observed do not impact MBW outcomes.Ĭitation: Ratjen F, Jensen R, Klingel M, McDonald R, Moore C, Benseler N, et al. Within the observed V T range, LCI was similar in trials with mean V T /kg below this range compared to trials with V T /kg within the range. For the majority of subjects with CF (80%), V T ranged from 9-15mL/kg. The LCI was lower, but not significantly different between deep breathing at 20 ml/kg body weight and uninstructed tidal breathing whereas LCI was significantly higher during shallow breathing compared with normal tidal breathing. In addition, we retrospectively analyzed MBW data from two pediatric multi-centre interventional studies of cystic fibrosis (CF) subjects to determine the range of V T observed during uninstructed breathing, and whether breathing outside this range impacted results. Healthy adult subjects performed MBW with uninstructed tidal breathing and a series of instructed tidal breathing tests, designed to isolate specific features of the breathing pattern. MBW testing was performed using the Exhalyzer ® D (EcoMedics AG, Switzerland). We aimed to assess whether changes in V T impact MBW outcome measures with a series of prospective and retrospective studies. For the MBW test to accurately reflect a subject’s gas mixing within the lungs, the breathing pattern should represent physiologically appropriate tidal volumes (V T) and respiratory rate (RR).
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