RT Journal Article SR Electronic T1 Infant lung function: Criteria for selecting tidal flow-volume loops JF ERJ Open Research JO erjor FD European Respiratory Society SP 00165-2022 DO 10.1183/23120541.00165-2022 A1 Karen Eline Stensby Bains A1 Hrefna Katrín Gudmundsdóttir A1 Martin Färdig A1 Erik Amnö A1 Christine M. Jonassen A1 Björn Nordlund A1 Eva Maria Rehbinder A1 Håvard O. Skjerven A1 Corina Silvia Rueegg A1 Riyas Vettukattil A1 Karin C. Lødrup Carlsen YR 2022 UL http://openres.ersjournals.com/content/early/2022/06/30/23120541.00165-2022.abstract AB Tidal flow-volume (TFV) loops are commonly recorded in infants during sleep, due to the more regular breathing patterns compared to the awake state. Standardised deselection of loops outside pre-specified ranges are based on periods of regular breathing, while criteria and available software for visual evaluation of TFV loops are lacking. We aimed to determine the reliability of standardised criteria for manual selection of infant TFV loops.Using a predefined set of criteria, three independent raters manually evaluated TFV loops among 57 randomly selected awake healthy 3-month-old infants with available TFV measurements in the Scandinavian PreventADALL study. The TFV loops were sampled using the Eco Medics Exhalyzer D. Criteria for selecting TFV loops included reproducible shape and volume with only one peak in tidal expiratory flow (PTEF), excluding loops with no clear or uneven flow towards PTEF. By intra class coefficient (ICC), the reliability of agreement between raters was determined for the time to PTEF to expiratory time (tPTEF/tE) and other TFV loop parameters.Five infants had unsuccessful tests. Among the remaining 52 infants the raters selected a median of 25, 26 and 15 loops per test, respectively. The ICC (95% confidence intervals) were 0.97 (0.92, 0.98) for tPTEF/tE, 0.99 (0.99, 1,00) for respiratory rate, 0.98 (0.97, 0.99) for tidal volume/kg and 0.98 (0.97, 0.99) for expiratory volume, reflecting excellent agreement in all categories.Manual TFV loops selection using standardised criteria provides a reliable alternative for lung function measures in awake infants with interrupted breathing cycles in a real-life setting.FootnotesThis manuscript has recently been accepted for publication in the ERJ Open Research. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJOR online. Please open or download the PDF to view this article.Conflict of Interest: The authors have no conflicts of interest to disclose, however Eva Maria Rehbinder has received honoraria for lectures from Sanofi-Genzyme, Novartis, Leo-Pharma, Perrigo and The Norwegian Asthma and Allergy Association.