Pocket-sized device for measuring forced expiratory volume in one second and forced vital capacity.

An inexpensive pocket-sized instrument--the turbine spirometer--has been developed that measures and gives a direct digital display of the forced expiratory volume in one second and forced vital capacity. The instrument is as accurate as and considerably cheaper than spirometers in general use. Condensation does not affect the calibration. The turbine spirometer will enable spirometry to be easily monitored in hospital wards and general practice and by patients at home.