Human lung deposition of particles suspended in air or in helium/oxygen mixture

Exp Lung Res. 1989 Jul;15(4):575-85. doi: 10.3109/01902148909069619.


Deposition in mouth and throat and the fraction of alveolarly deposited particles in the lung of 3.6- to 3.8-microns Teflon particles labeled with 99mTc were estimated in nine healthy subjects. The particles were inhaled in air or helium/oxygen mixture with a flow of 0.5 l/s by subjects with or without induced bronchoconstriction. The bronchoconstriction (two- to threefold increase in airway resistance) was induced by an aerosol of methacholine bromide. As the Reynolds number is three times lower for the helium/oxygen mixture than for air, and the sedimentation rate of the particles is about the same in both, a different regional deposition between particles suspended in air and helium/oxygen mixture should be due to turbulence. Deposition in mouth and throat did not differ significantly between air and the helium/oxygen mixture. The alveolarly deposited fraction tended to be larger for unconstricted airways and was significantly larger for constricted airways for inhalations in the helium/oxygen mixture compared to air. In real life, air pollutants and therapeutic aerosols may be inhaled with larger flow rates and broncho-constriction may be more pronounced in patients, so that deposition of particles due to turbulence can be important.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Inhalation
  • Adult
  • Airway Resistance / drug effects
  • Bronchi / metabolism*
  • Female
  • Helium / pharmacokinetics*
  • Humans
  • Male
  • Methacholine Chloride
  • Methacholine Compounds / pharmacology
  • Microspheres*
  • Mouth / metabolism*
  • Oxygen / pharmacokinetics*
  • Pharynx / metabolism*
  • Polytetrafluoroethylene


  • Methacholine Compounds
  • Methacholine Chloride
  • Helium
  • Polytetrafluoroethylene
  • Oxygen