Impedance Pneumography in Healthy and Sick Children Aged Between 2 and 35 Months

Impedance pneumography (IP) non-invasively records tidal breathing flow-volume curves over long durations. It measures the ratio of time to peak tidal expiratory flow relative to the total expiration time (T_PTEF/T_E) and the Expiratory Variability Index (EVI), which assesses the variability of expiratory flow in the early phase of expiration with a decrease in case of clinical symptoms of bronchial obstruction.

To establish reference values for EVI and T_PTEF/T_E, recorded at home during sleep using IP.

We conducted a bi-centre prospective study to recorded EVI and T_PTEF/T_E over at least 4 h of sleep, using IP measurement Ventica® (Icare Finland Oy, Finland), in healthy and sick (non-wheezy and wheezy) children, aged 2 to 35 months.

Among the 67 healthy children included, 59 were successfully recorded by parents (median [Q1; Q3] (range) age 15.4 [8.6; 26.0] (2.3-35.9) months) and showed median [Q1; Q3] (5th; 95th percentiles) EVI of 16.7 [14.9; 18.9] (12.7; 20.7); and T_PTEF/T_E (n = 51) of 0.18 [0.16; 0.22] (0.13; 0.26). In 9 non-wheezy children with respiratory symptoms and 12 wheezers, EVI (13.5 [9.6; 14.6] and 7.0 [6.0; 12.5], respectively) and T_PTEF/T_E (0.16 [0.13; 0.18] and 0.12 [0.09; 0.18], respectively) were significantly lower compared to healthy. The values of EVI and T_PTEF/T_E in 68 healthy and sick children with both measurements (12 missing data) were concordant (> or < 5th percentile) in 62 cases (91%).

We provide reference values of EVI and T_PTEF/T_E measured at home by parents using IP in young children. IP shows lower values in wheezy and non-wheezy sick young children.