Muscle Relaxants and Laryngeal Local Anesthetics for Laryngeal Mask Airway Insertion Decreasing Propofol in Elderly

10% lidocaine spray 3 puff for the throat before induction

Normal saline spray 3 puff for the throat before induction

Intravenous cisatracurium 0.12 mg/kg during induction

Intravenous normal saline during induction

The dosage of intravenous propofol for the first subjects was predetermined for each arm, and the dosage for the subsequent subjects would be determined according to the response of the previous subjects using the Dixon's up-and-down method with a step size of 0.25 mg/kg. If the subjects had no movement and stable hemodynamic status during and after the laryngeal mask airway (LMA) placement, the predetermined dosage of propofol for the subsequent subject would be decreased by 0.25 mg/kg. On the other hand, if the subjects had obvious movement, failure to LMA placement, and significant hemodynamic changes, the predetermined dosage of propofol for the subsequent subject would be increased by 0.25 mg/kg.