Late Breaking Abstract - Expiratory variability index (EVI) in young children during asthma exacerbation

Abstract

Background: Diminished variability of the expiratory flow profiles measured using impedance pneumography (IP) during night’s sleep is associated with lower airway obstruction (LAO) in young children with recurrent wheeze (Seppa et al. ERJ Open Res 2019, accepted). Aims and Objectives: We aimed to investigate, how an acute LAO and recovery thereof reflects on the change in expiratory variability index (EVI) in a longitudinal setting. Methods: EVI was measured using a wearable IP system (Ventica, Revenio Research Ltd., Vantaa, Finland) during sleep at night in healthy controls (both sexes aged 4.3 [1.5-6.0] y) and patients hospitalised due to acute LAO (both sexes, aged 3.5 [1.3-6.0] y). In-patients were measured for several nights, as practically feasible, and for 1-2 nights at home after first and second control visit (2 and 4 weeks post-discharge). The controls were measured for 1-3 nights at their homes. Results: We received 79 recordings from 37 controls and 141 from 29 patients. Compared to the controls, EVI of the patients was lower during the in-patient period (rank sum p Conclusions: EVI shows to be a sensitive, objective marker of acute LAO prone to change with the clinical status in children aged 1-5 years.