Related Experiment Video
Updated: Sep 23, 2026

Modeling and Simulations of Olfactory Drug Delivery with Passive and Active Controls of Nasally Inhaled Pharmaceutical Aerosols
Published on: May 20, 2016
The impact of expiration on particle deposition within the nasal cavity
K Wiesmiller1, T Keck, R Leiacker
1Department of Otorhinolaryngology, University of Ulm, Ulm, Germany. kerstin.wiesmiller@medizin.uni-ulm.de
Abstract:
One of the most important functions of the nose is cleansing the inspired air. The aim of this study was to compare the intranasal deposition of particles during inspiration and expiration, applying different breathing manoeuvres. In nine subjects, the non-deposited particles during inhalation of an aerosol of starch particles were laser-optically detected by placing a suction probe transnasally in the anterior nasal segment. The particle deposition was measured during cyclical nose-in/nose-out (nose-only) and nose-in/mouth-out breathing. The deposited fraction was calculated in percentages. Active anterior rhinomanometry and acoustic rhinometry were performed. The mean deposited fraction in the anterior nasal segment was statistically significantly higher (P < 0.02) during nose-only breathing (46.0%) compared with nose-in/mouth-out breathing (33.0%). Our results suggest that intranasal particle deposition takes place during inspiration as well as during expiration. The period of expiration does not only seem to be important for water and heat recovery, but also for cleansing of the respiratory air.
Related Concept Videos
Nose and Nasal Cavity
Pulmonary Cycle: Exhalation
Pressure Relationships in Thoracic Cavity
Breathing Mechanisms
Both intra-alveolar and intrapleural pressures rely on specific lung properties. The ability to breathe—allowing air to enter the lungs during...
Pulmonary Ventilation: Inhalation
Boyle's law becomes particularly pertinent when examining respiratory...
Factors Affecting Pulmonary Ventilation
Alveolar Surface Tension
The alveolar fluid lines the luminal surface of the alveoli and exerts a force called surface tension. This force is caused by the polar water molecules in the liquid being more strongly attracted to each...
Suctioning the Nasopharyngeal Airway
Equipment Required

