Sources of variability in expiratory flow profiles during sleep in healthy young children

Published in: Respiratory Physiology & Neurobiology journal 2019

Authors: Anton Hult, Romana Gjergja Juraški, Javier Gracia-Tabuenca, Markku Partinen, Davor Plavec and Ville-Pekka Seppä


• First analysis of tidal breathing flow-volume curves by sleep stages.
• Curves are more similar within individual N3 cycles than in other sleep stages.
• Curves are substantially different between separate N3 cycles.
• Body position changes have lesser impact on the curves than sleep stage changes.

Standard lung function tests are not feasible in young children, but recent studies show that the variability of expiratory tidal breathing flow-volume (TBFV) curves during sleep is a potential indirect marker of lower airway obstruction. However, the neurophysiological sources of the TBFV variability in normal subjects has not been established.

We investigated sleep stages and body position changes as potential sources for the TBFV curve variability. Simultaneous impedance pneumography (IP), polysomnography (PSG) and video recordings were done in 20 children aged 1.4–6.9 years without significant respiratory disorders during sleep.

The early part of expiratory TBFV curves are less variable between cycles of REM than NREM sleep. However, within individual sleep cycles, TBFV curves during N3 are the least variable. The differences in TBFV curve shapes between sleep stages are the main source of overnight variability in TBFV curves and the changes in body position have a lesser impact.

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