A novel mainstream capnometer system for polysomnography integrated with measurement of nasal pressure and thermal airflow

Capnometry is a method to measure carbon dioxide (CO₂) in exhaled gas and its use during polysomnography (PSG) for diagnostic of sleep apnea-hypopnea syndrome is expanding. However, some problems exist for using capnometer in combination with other respiratory monitoring devices because capnometry requires additional sampling cannula or airway adapter attached to patients. To resolve these problems, we developed a novel mainstream capnometer system for PSG, which is designed to integrate multiple devices for measuring respiratory parameters. This system may provide comfortable and stable PSG including capnometry. We evaluated the basic performance of this system using a spontaneous breathing model. The result indicates that this newly developed system works adequately in PSG and moreover has superior characteristics of capnography signal and measurement stability against displacement of sensors, compared to conventional devices.