Background: Laboratory evaluation of VHC-facemask add-ons is ideally undertaken simulating conditions-of-use. We report a study in which VHCs for small child use (n=3/group) (AeroChamber Plus® Flow-Vu® anti-static/child mask (aAC+); PocketChamber® (POC); Vortex® (VOR); SpaceChamber Plus® (SP); A2A Spacer® (A2A); Able Spacer™-2 (AB2)) were evaluated using an anatomical face/ 4-year child oropharynx model (ADAM-III).
Materials and Methods: Each VHC was evaluated out-of-package (OOP), but the non-anti-static devices were also washed with mild detergent / drip-drying (W). Performance was evaluated by breathing simulator (tidal volume = 155-mL, inspiratory: expiratory (I:E) ratio = 1:2, rate/min = 25 cycles). The facemask was attached to the model face following a 2-s coordination delay post pMDI actuation. The airway was coupled directly to the breathing simulator via an exit filter capturing fine particles that could theoretically penetrate as far as the carina in a patient (FPcarina). 5-actuations of fluticasone propionate (50 μg FP/actuation ex actuator) were delivered at 30-s intervals. Recovered FP was assayed by HPLC-UV spectrophotometry.
Results: Values of FPcarina (μg/actuation; mean±SD) were 10.5±1.0 (aAC+/OOP); 4.0±1.7 (POC/OOP); 0.7±1.1 (VOR/OOP); 1.0±0.3 (SP/OOP); 5.0±1.4 (SP/W); 0.6±0.1 (A2A/OOP); 4.1±0.9 (A2A/W); 0.3 ± 0.1 (AB2/OOP);4.8 ± 0.9 (AB2/W).
Conclusions: Significantly more FP was delivered to the model ‘carina’ from the aAC+ VHC (1-way ANOVA; p < 0.001); associated primarily with decreased VHC retention of medication. Large differences in delivery efficiency may exist when using different VHC-facemask delivery systems. Some of the difference can be eliminated by pre-conditioning non-anti-static devices before first use, however even when this is performed significant differences still exist.