 Methods: 45 patients American Society of Anesthesiologists ASA class I or II aged 20-60 years undergoing ambulatory elective surgery were randomized to either the LMAS or LMAP. The patients were premedicated with midazolam 1 mg iv before surgery. All patients were preoxygenated using 100 oxygen with a normal tidal volumen for 3 min. The circuit was primed with sevoflurane 5 at a fresh gas flow of 6 Lmin for 1 min. Anaesthesia was induced with inhaled sevoflurane up to 5 in oxygen via facemask with fresh gas flow at 6 Lmin. Simultaneously remifentanil at an effect-site of 4 ngml was started. Target-controlled infusions was used Alaris PK for remifentanil administration. After loss of consciousness, the inspired concentration of sevoflurane was changed to obtain a predetermined end-tidal concentration. A single experienced anaesthetist in the use of supraglottic devices inserted the devices according to the manufacturers recommendations. The LMAs size was chosen according to the sex of the patients, size 4 for women and size 5 for men; however for patients weighing 50 kg a size 3 was inserted. Neuromuscular blocking agents were not given. Two nurses, who were blinded to the anaesthetic concentration, classified responses by the patient to LMA insertion as either movement or not movement. Assesment was made for jaw relaxation and graded with Muzi score. A Muzi score 2 was defined as a failure of insertion. The end-tidal ET sevoflurane concentration used for each patient was determined using the Dixons up-and-down method. The ratio of the end-tidal to predetermined end-tidal concentrations was maintained at 0.9-1.0 for at least 10 minutes to establish equilibration before device insertion was attempted. The first patient received a 2.5 sevoflurane concentration and the step size of increasedecrease was 0.5. If the supraglottic device LMAS or LMAP insertion was successful, sevoflurane concentration for the next patient was decrease by 0.5. If not, sevoflurane concentration was increased by the same amount for the next patient. For their comfort, patients experiencing movement received a 1-2 mgkg bolus dose of propofol. 