ABSTRACT
This chapter deals mainly with spirometry, i.e., with the measurement of volumes and flows associated with respiration. Spirometric tests are often used for diagnostic purposes in conjunction with other measurements. A widely used spirometer is the bell type: the volume of the lungs is monitored by the position of a light cylindrical bell (possibly equipped with counterweights) connected to the patient’s mouth. The main limitation of the turbine meter is that low flow values are underestimated since a greater fraction of the air slips past the wheel as the flow rate decreases; it also displays poor frequency response and can be used only in unidirectional flows.
