A<unk>  is an apparatus for measuring the volume of air inspired and expired by the lungs. A<unk>  measures ventilation, the movement of air into and out of the lungs. The spirogram will identify two different types of abnormal ventilation patterns, obstructive and restrictive. There are various types of<unk> s that use a number of different methods for measurement (pressure transducers, ultrasonic, water gauge).
Spirometer
Respirometer
Respiratory pressure meter
Gaseous detection device
Incentive spirometer
Carbon monoxide detector
Spirometry
Structured light plethysmography