TY - JOUR T1 - Infant lung function: criteria for selecting tidal flow–volume loops JF - ERJ Open Research JO - erjor DO - 10.1183/23120541.00165-2022 VL - 8 IS - 4 SP - 00165-2022 AU - Karen Eline Stensby Bains AU - Hrefna Katrín Gudmundsdóttir AU - Martin Färdig AU - Erik Amnö AU - Christine M. Jonassen AU - Björn Nordlund AU - Eva Maria Rehbinder AU - Håvard O. Skjerven AU - Corina Silvia Rueegg AU - Riyas Vettukattil AU - Karin C. Lødrup Carlsen Y1 - 2022/10/01 UR - http://openres.ersjournals.com/content/8/4/00165-2022.abstract N2 - Background 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.Methods Using a pre-defined 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 Preventing Atopic Dermatitis and ALLergies in children (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 intraclass coefficient (ICC), the reliability of agreement between raters was determined for the time to PTEF (tPTEF) to expiratory time (tE) and other TFV loop parameters.Results Five infants had unsuccessful tests. Among the remaining 52 infants, the raters selected a median of 25, 26 and 15 loops per test. The ICCs (95% CI) 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 per kg and 0.98 (0.97–0.99) for expiratory volume, reflecting excellent agreement in all categories.Conclusion Manual TFV loop selection using standardised criteria provides a reliable alternative for lung function measures in awake infants with interrupted breathing cycles in a real-life setting.A pre-defined set of inclusion and exclusion criteria provide a reliable and standardised procedure for manual selection of tidal flow–volume loops in infants, which may be useful in clinical and research settings https://bit.ly/3NYMlp0 ER -