During propofol induction, BIS values, MAP, HR and SpO2 will be recorded every 1-min and the Observer's Assessment of Alertness/Sedation (OAAS) rating scale will be recorded after each equilibration period (score 5=awake and responds readily to name spoken in normal tone; 4= lethargic response to name in normal tone; 3=response only after name is called loudly and/or repeatedly; 2= response only after name is called loudly and after mild shaking; 1= dose not respond when name is called and after mild shaking).