Targeting the Lungs During Nose Breathing

Total and Regional Deposition After Nose Breathing 

Experimental data on total and regional deposition during nose breathing were obtained by Heyder et al. (99) in healthy adult volunteers who inhaled monodis-perse particles with increasing particle diameter through the nose at a fixed flow 

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Heyder et al. found that particles 3 pm do penetrate beyond the nose and deposit primarily in the alveolar region. However, the number of particles that bypass the nose appears to be lower than what is predicted from the model (i.e., -20%). In addition, only about 3% of 1- to 5-pm particles deposit in the bronchial airways during nose breathing. Therefore, if one is interested in targeting those airways, it will be necessary to administer large amounts of aerosol to compensate for the losses in the nose. 

The above data were obtained in healthy adnlt volnnteers. Chua et al. (100) quantified the deposition of a polydisperse aerosol in the Inngs of eight children with cystic fibrosis (median age = 10.8 years range = 6.3-18.0 years), who breathed via the nose with a face mask and closed month on one occasion and via the oral route with a mouthpiece on another. Aerosol was generated by nebu- 

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