Infant lung function: Criteria for selecting tidal flow-volume loops

  1. Karen Eline Stensby Bains1,2⇑,
  2. Hrefna Katrín Gudmundsdóttir1,2,9,
  3. Martin Färdig3,4,9,
  4. Erik Amnö3,
  5. Christine M. Jonassen5,6,
  6. Björn Nordlund3,4,
  7. Eva Maria Rehbinder1,7,
  8. Håvard O. Skjerven1,2,
  9. Corina Silvia Rueegg8,
  10. Riyas Vettukattil1,2 and
  11. Karin C. Lødrup Carlsen1,2
  1. 1University of Oslo, Faculty of Medicine, Institute of Clinical Medicine, Oslo, Norway
  2. 2Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
  3. 3Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
  4. 4Department of Womeńs and Childreńs Health, Karolinska Institutet, Stockholm, Sweden
  5. 5Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
  6. 6Centre for Laboratory Medicine, Østfold Hospital Trust, Kalnes, Norway
  7. 7Department of Dermatology, Oslo University Hospital, Oslo, Norway
  8. 8Oslo Centre for Biostatistics and Epidemiology, Oslo University Hospital, Oslo, Norway
  9. 9shared second authorship
  1. Corresponding author: Karen Eline Stensby Bains, MD. Department of Pediatrics, Ullevål, Oslo University Hospital. Postboks 4956 Nydalen. 0424 Oslo, Norway. E-mail: karen.eline.sh{at}gmail.com Mobile: +4797745444.

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

This 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.

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  • Received April 2, 2022.
  • Accepted July 3, 2022.
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