Infant tidal flow-volume parameters and arousal state

Karen Eline Stensby Bains; Martin Färdig; Hrefna Katrín Gudmundsdóttir; Catarina Almqvist; Gunilla Hedlin; Live S Nordhagen; Eva M Rehbinder; Håvard O Skjerven; Cilla Söderhäll; Riyas Vettukattil; Björn Nordlund; Karin C Lødrup Carlsen

doi:10.1183/23120541.00163-2022

Infant tidal flow-volume parameters and arousal state

ERJ Open Res. 2022 Oct 17;8(4):00163-2022. doi: 10.1183/23120541.00163-2022. eCollection 2022 Oct.

Authors

Karen Eline Stensby Bains^{1

2

3}, Martin Färdig^{4

5

3}, Hrefna Katrín Gudmundsdóttir^{1

2}, Catarina Almqvist^{5

6}, Gunilla Hedlin^{4

5}, Live S Nordhagen⁷, Eva M Rehbinder^{2

8}, Håvard O Skjerven^{1

2}, Cilla Söderhäll^{4

5}, Riyas Vettukattil^{1

2}, Björn Nordlund^{4

5}, Karin C Lødrup Carlsen^{1

2}

Affiliations

¹ Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway.
² University of Oslo, Faculty of Medicine, Institute of Clinical Medicine, Oslo, Norway.
³ These authors contributed equally and share first authorship.
⁴ Dept of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
⁵ Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.
⁶ Dept of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
⁷ VID Specialized University, Oslo, Norway.
⁸ Dept of Dermatology, Oslo University Hospital, Oslo, Norway.

Abstract

Background: Infant lung function can be assessed with tidal flow-volume (TFV) loops. While TFV loops can be measured in both awake and sleeping infants, the influence of arousal state in early infancy is not established. The aim of the present study was to determine whether TFV loop parameters in healthy infants differed while awake compared to the sleeping state at 3 months of age.

Methods: From the population-based Scandinavian Preventing Atopic Dermatitis and ALLergies in children (PreventADALL) birth cohort, 91 infants had reproducible TFV loops measured with Exhalyzer^® D in both the awake and sleeping state at 3 months of age. The TFV loops were manually selected according to a standardised procedure. The ratio of time to peak tidal expiratory flow (t _PTEF) to expiratory time (t _E) and the corresponding volume ratio (V _PTEF/V _E), as well as tidal volume (V _T) and respiratory rate were compared using nonparametric tests.

Results: The mean (95% CI) t _PTEF/t _E was significantly higher while awake compared to the sleeping state: 0.39 (0.37-0.41) versus 0.28 (0.27-0.29); with the corresponding V _PTEF/V _E of 0.38 (0.36-0.40) versus 0.29 (0.28-0.30). The V _T was similar, while the respiratory rate was higher while awake compared to the sleeping state: 53 (51-56) breaths·min^-1 versus 38 (36-40) breaths·min^-1.

Conclusion: Higher t _PTEF/t _E, V _PTEF/V _E and respiratory rate, but similar V _T while awake compared to the sleeping state suggests that separate normative TFV loop values according to arousal state may be required in early infancy.