Mechanical Insufflation-Exsufflation: Room for Improvement.

The author discusses an in vitro study that examines the movement of mucus over a tube actuated with a mechanical insufflation-exsufflation device set at different combinations of flow and pressure. The reproducibility to achieve the low insufflation flow manually has not been evaluated. The flow is said to be clearly correlated to the shear stress in a given geometry. It is said that a viscoelastic and a shear-thinning behavior with some thixotropy are often evoked.