Facemasks and facial deposition of aerosols

Passage of aerosol around or through a facemask can result in deposition on the face and in the eyes. The present study quantified facial and eye deposition in a model simulating drug delivery to a young child. Aerosol delivery and facial deposition of radiolabeled saline test aerosols were studied in vitro with filters and a gamma camera. A child's face facsimile, attached to a piston pump, was used to simulate the patient receiving aerosol therapy. A filter placed in the oropharynx of the face facsimile measured aerosol delivery (inhaled mass). Seven commercially available facemasks in combination with three jet nebulizers were studied for aerosol delivery to the "patient" as well as for deposition on the face and in the eyes. Inhaled mass varied from 2.24-5.96% of nebulizer charge (drug placed in the nebulizer). Facial deposition varied from 0.44-2.34% of nebulizer charge, with eye deposition at 0.09-1.78%. All facemasks leaked aerosol, with significant facial and eye deposition approaching in magnitude delivery to the lung. Factors affecting facial and eye deposition include the interactive design characteristics of the facemask and nebulizer, as well as the aerodynamic properties of the aerosol.