Introduction and Objectives Laboratory evaluation of VHC-facemask add-ons is ideally undertaken simulating conditions of use. We report a study in which such devices for small child use were evaluated using an anatomical face-model and upper airway commensurate with that of a 4 year old child.

Methods A number of VHCs with facemask (n=3 devices/group) were evaluated using an anatomical face-model and upper airway commensurate with that of a 4 year old child. Each VHC was prepared to manufacturer instructions, then evaluated by breathing simulator (ASL5000), mimicking a short coordination delay of 2 s followed by tidal breathing (tidal volume (Vt)=155 mL, I:E ratio=1:2, rate=25 cycles). The facemask was attached to ADAM-III small child model. The airway was coupled directly to the breathing simulator via a filter below its exit to capture drug particles that would penetrate as far as the carina in a real patient. 5-actuations of fluticasone propionate (50 µg, FP) were delivered at 30 s intervals. FP recovered from various locations in the aerosol pathway was subsequently assayed by HPLC-UV spectrophotometry.

Results Distribution of recovered FP from each type of VHC is summarised in Table 1.

Conclusions Significantly more FP was delivered to the model ‘carina’ from the AC Plus VHC with child mask (p<0.001), the increased mass counterbalanced by decreased retention of medication within the VHC. It is important that clinicians are aware that large differences in delivery efficiency may exist when a facemask is present.