Rationale - Forced oscillation technique (FOT) is a very feasible and reliable technique for young children. A new equipment has recently been released on the market, which is based on intrabreath analysis of respiratory impedance. Aim of this study was to verify the applicability of previously published FOT reference values to the new equipment.
Methods - Children were recruited in randomly selected kindergartens using a standardized questionnaire (modified ISAAC), translated into Italian. Preemies (<36 weeks of gestational age) or children who had received oxygen therapy at birth for >30 days were excluded. Other exclusion criteria were history of asthma diagnosed by a physician and wheezing during the previous 12 months or >3 episodes of wheezing ever. FOT was performed with a Resmon Pro Full device (Restech Srl, Milan, Italy). To allow the comparison with previously published reference values (Calogero, C. et al. Pediatr Pulmonol 2010;45:1086-94) measured with the "i2m" device (Cosmed, Rome, Italy), total resistance (R8tot) and reactance (X8tot) at 8 Hz were calculated as the mean of at least 3 acceptable measurements, as recommended (Beydon, N. et al. Am J Respir Crit Care Med 2007;175:1304-45).
Results - A total of 38 healthy children (18 male, 20 female; age 3.2-6.3 yr) were tested. Mean (SD) respiratory impedance indices are reported in the table.
Conclusions - Although the difference was minimal for R8, impedance values measured in a small sample size of healthy prechoolers using intrabreath analysis were statistically different from those previously published.