Pressure gradient and inspiratory times required for valve opening of various holding chambers

This study was designed to determine whether infants generate sufficient inspiratory pressure gradient to open the unidirectional valve of various commercially available holding chambers, as well as the time required to reach this gradient. A prospective, cross-sectional study was performed of 80 healthy infants (aged 1‐24 months) seen in the childcare outpatient clinic of a pediatric hospital, from October to December of 2007. Using the same inhalation technique recommended for treatment of respiratory diseases and asthma in this age group, four holding chambers were analyzed: Flumax Baby, AlergoChamber, LuftChamber, and ACE (n = 20 infants per analysis group). The variables measured were gradient of inspiratory pressure and time for the valve to open. The holding chambers did not differ in gradient of inspiratory pressure (p = 0.382) or time to open the valve (p = 0.199). Fifteen of 80 infants were not able to generate sufficient inspiratory pressure to open the valve (1 using AlergoChamber, 5 using Flumax Baby, 6 using ACE, and 3 using LuftChamber), with no significant differences between devices. The holding chambers were similar regarding pressure gradient and time required to open the valve. The fact that 19% of the sample was unable to open the valve suggests that it would be useful to determine the ability of small children (<24 months of age) to use holding chambers before prescribing them.