adult ASA physical status I–II patients aged 18–65 yr undergoing elective orthopedic, plastic, or gynecologic procedures were enrolled in the study.

Day surgery cases and in-patients were included. Patients with a history of difficult intubation (or likely to be difficult to intubate), gastroesophageal reflux, allergy, or sensitivity to volatile anesthetics or to propofol, those with a body mass index more than 1.5 times normal, heavy smokers (>=20 cigarettes per day), and patients taking any sedative drugs that influence the induction anesthetic were excluded from the study