Abstract
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.
Footnotes
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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.
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- Received April 2, 2022.
- Accepted July 3, 2022.
- Copyright ©The authors 2022
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