The parameters of mean arterial pressure ( MAP ) , heart rate ( HR ) , pressure of end-tidal carbon dioxide ( P ETCO2 ) , respiratory rate , blood oxygen saturation ( SpO2 ) , observer 's assessment of alertness/sedation ( OAA/S ) and verbal rating score ( VRS ) were recorded at 0 min ( baseline ) , 5 min ( T1 ) , 10 min ( T2 ) , 15 min ( T3 ) , 20 min ( T4 ) , 30 min ( T5 ) and 60 min ( T6 ) after the dosing of Dex .