Mucus transport by high-frequency nonsymmetrical oscillatory airflow

J Appl Physiol (1985). 1988 Sep;65(3):1203-9. doi: 10.1152/jappl.1988.65.3.1203.


To study air-mucus interaction as a possible mechanism of tracheal mucus transport and to test the validity of using surface tracer displacement to indicate bulk mucus transport, we performed a combined experimental-theoretical study. We hypothesized that the mucus mass is moved by the difference between expiratory and inspiratory velocities. The rate of transport of a layer of simulated mucus lining the bottom of a rectangular trough was measured in two ways during oscillatory air flow. Peak velocity ratios (R) from 1.0 to 2.0, frequencies (f) between 7 and 13 Hz, and tidal volumes (VT) between 50 and 100 ml were generated by a custom-made pump. The experimental results demonstrate that measuring the displacement of a tracer deposited on the surface of the mucus layer is equivalent to measuring bulk mucus movement by weight. Moreover the measured mucus velocities (micron) correlate well with a theoretical model which predicts that micron is proportional to delta VT f1.5 (R-1). These results suggest that shearing at the air-mucus interface could be a significant factor in the enhanced tracheal mucus clearance during high-frequency chest wall oscillation.

MeSH terms

  • Animals
  • Biological Transport, Active
  • Elasticity
  • High-Frequency Ventilation*
  • Humans
  • In Vitro Techniques
  • Models, Biological
  • Models, Theoretical
  • Mucus / physiology*
  • Tidal Volume
  • Viscosity