Figure 2: Changes in TC-CO2 and ETCO2 using a nasal cannula during ntravenous sedation. The TC-CO2 increased after midazolam injection and tended to decrease after flumazenil injection, and there were significant differences between the values 5 to 16 min after injection and that before injection. The ETCO2 using the nasal cannula tended to decrease after injection, and that using the mouthnose cannula tended to increase immediately after injection. The accuracy increased after midazolam injection and decreased after flumazenil injection. The mean accuracy between TC-CO2 and ETCO2 ranged from 3 to 9 mmHg during sedation using the nasal cannula (n=8).