Become an
Expert in Spirometry

Detecting airway obstruction

Division into upper and lower airwaysAirway obstruction may be present during inspiration and during expiration. It may be due to abnormalities in ‘upper airways’ (from the nose and mouth up to and including the extrathoracic trachea) and in ‘lower airways’ (all airways within the thorax). Obstruction in upper airways can sometimes be detected from forced inspiratory maneuvers, whilst forced expiratory maneuvers are required to disclose obstruction in lower airways. Why this is so is explained in this section.
A synopsis of the effect of forced inspiratory and expiratory maneuvers on airway calibre, and hence on flows, is shown in the animation.

Content on this page requires a newer version of Adobe Flash Player.

Get Adobe Flash player

Top of page | | | ©Philip H. Quanjer