Blowby vs face mask for nebulized drugs in young children

Abstract

Rationale Effective drug delivery to the lungs of infants and toddlers depends on proper nebulization technique and prevention of crying. We compared the inhaled fine particle dose from a T-piece nebulizer in an in vitro model using close-fitting face mask, blowby with mask, and blowby with a corrigated extension tube. Methods A VixOne nebulizer filled with unit dose albuterol solution was used for all experiments. Breathing patterns of young children were simulated with a PARI COMPASS device with breath rate of 30/min and tidal volumes (Vt) of 50, 100, and 200 ml. Aerosol was delivered via close-fitting face mask, blowby with face mask or corrigated tubing held 2 cm away from an artificial nose model. Albuterol was captured on a filter and analyzed by spectrophotometry. Albuterol particle size was measured with an Insitec laser, and the “lung dose” (fine particle dose captured on the filter) was calculated. Results The estimated lung dose for mask, mask blowby, and tube blowby at Vt=50 ml were 0.06, 0.03 and 0.08 mg respectively. Lung dose for Vt=100 ml were 0.11, 0.08, and 0.12 mg. Lung dose for Vt=200 ml were 0.18, 0.10 and 0.16 mg. Nebulization time was 7 minutes. Conclusions Lung dose increased with higher Vt. Blowby with mask decreased lung dose at all Vt, but blowby with extension tube was similar to the close-fitting mask. These data suggest that blowby with an extension tube (but not with a mask) is an acceptable alternative to a close-fitting mask, especially if it prevents fussiness of the child.