A Novel Nasal Cannula Type Mainstream Capnometer System Capable of Oxygen Administration.

Capnometry is a method to measure carbon dioxide (CO) in exhaled gas and has been used to monitor patient's respiratory status. During moderate or deep sedation, monitoring for the presence of exhaled CO is recommended for evaluating the adequacy of ventilation. Oxygen administration is usually given to patients with a nasal cannula to avoid hypoxia during sedation. However, the flow of oxygen administration can interfere with CO measurement. We developed a nasal cannula type adapter called cap-ONE nasal adapter system based on the mainstream capnography which is designed to monitor CO while supplying oxygen. In this study, we evaluated the basic performance of the system as compared with a conventional device using a spontaneous breathing model. The cap-ONE nasal adapter system could accurately measure PetCO without being disturbed by oxygen flow and efficiently supply oxygen.