Remimazolam, a brand-new sedative which has benzodiazepine property. It is an ultra-short acting sedative and regarded as a proper drug for procedural sedation.

As ambulatory surgery has been increased last two decades, 'Enhanced Recovery After Surgery (ERAS)' also has become an important issue in clinical fields.

It is very critical that managing postoperative pain, postoperative nausea and vomiting (PONV) and rapid recovery with less complication or side effect to anesthesiologists.

Even though remimazolam considered as an ultra-short acting sedative, it shows a relatively longer recovery time than propofol. Fortunately, remimazolam has its own antidote, called 'flimazenil'. With flumazenil, the time to recovery of consciousness dramatically reduces.

Common side effects of flumazenil include headache, dizziness, nausea, vomiting, flushing, sweating and injection pain.

In this trial we would like to demonstrate that routine single dose of flumazenil could be administered as an antidote of remimazolam without complications or side effects in gynecologic ambulatory surgery.

Inclusion Criteria:

• participants aged over 20 years scheduled for ambulatory gynecologic surgery.

Exclusion Criteria:

• allergy or hypersensitivity to flumazenil, benzodiazepines, NSAIDs, 5-HT3
• arrhythmia, myocardial infarction, coronary artery disease
• obstructive sleep apnea
• severe or acute respiratory distress
• tricyclic anti-depressant
• lactose intolerance
• BMI over 30kg/m2
• ASA classification 4 or 5

participants and outcome assessors are blinded to which group participants are allocated.