Respiratory devices

During exercise, muscles require more oxygen and produce increased carbon dioxide. Gas exchange can be monitored by measuring oxygen uptake and carbon dioxide production. Cardiopulmonary Exercise Testing (CPET) analyzes breath gases to assess pulmonary gas exchange, cardiovascular performance, and muscle metabolism. The lecture will describe the different methods, i.e. algorithms, digital computer analysis and sensors, which are used to sample airflow and measure fractional concentrations of CO2 and O2 near the mouth. These include the bag collection, the mixing chamber and the breath-by-breath techniques. The lecture will also describe the measurement devices used in pulmonary function and exercise testing, including airflow or volume transducers such as differential pressure sensors, pneumotachographs, thermal mass flow sensors, and turbine volume transducers. In addition, it will describe the use of gas analyzers, such as mass spectrometers and separate analyzers for O2 and CO2, to measure gas concentrations. Finally, a mention to the new developments of portable and wearable devices will be provided.