1.Written informed consent must be obtained before any study specific procedures are undertaken.Qualified participants were identified at the pre-anesthesia evaluation clinic or ward.

2.80 patients with American Society of Anesthesiologists (ASA) score of I-II in our medical center scheduled to undergo elective surgery for hypertrophy of labia minor with MAC. Patients were randomized 1:1 into the Group 1 (normal saline) or Group 2 (lidocaine 1.5 mg/kg/hr, ideal body weight) by using a table of random, computer-generated digits in sealed and numbered envelopes by an anesthesiologist. All surgical procedure was performed by the same surgeon and the anesthetic data was recorded by a nurse anesthetist. All patients were fasted overnight before the procedure, and no medications were allowed before induction of anesthesia. Standard monitoring, such as non-invasive arterial blood pressure, electrocardiography (lead II), pulse oximetry, end-tidal carbon dioxide pressure (EtCO2) was applied for each patient. Participants were pre-oxygenated and adequately maintained with 100% oxygen at 3 L/min via a nasal cannula during the entire procedure. During anesthesia induction, all patients received intravenous fentanyl 0.5-1 mcg/kg, continuous infusion of propofol with target-controlled infusion (TCI; Fresenius Orchestra Primea; Fresenius Kabi AG, Bad Homburg, Germany) with the Ce of 4.0 mcg/mL and parecoxib. In addition, continuous infusion of equal volume normal saline and lidocaine 1.5 mg/kg/hr (ideal body weight) in group I and 2, respectively. In all patients, maintenance of the Ce of propofol was adjusted upward or downward by 0.5 mcg/mL to keep patient adequate sedation with acceptable pain (remaining moveless). If upward 2 times of propofol and the patient still move which affect the surgical procedure, fentanyl 0.5 mcg/kg was prescribed, and mean arterial pressure (MAP) and heart rate (HR) within baseline levels. As soon as the last suture, the propofol and lidocaine were discontinued. After the procedure, all patients were sent to the PACU for further care under clear consciousness.

Patients were monitored for MBP, HR, peripheral oxygen saturation (SpO2), respiratory rate (RR), EtCO2, Ce of propofol, BIS values, OAA/S at the T1: before anesthesia induction, T2: time of the skin incision, T3: 15 minutes after the skin incision, T4: 30 minutes after the skin incision, T5: 45 minutes after the skin incision, T6: time of the beginning skin suture, and T7: time of the end of procedure. Collected data also include the time that the surgery ended, the total usage of propofol and fentanyl, the frequency to adjustment of TCI, times of patient move affect the procedure, and the surgeon's satisfaction. At PACU, patients were monitored for HR, MBP, SpO2, RR, NRS, RASS, length of stay, PONV and patient satisfaction (scoring 1-5).

Inclusion Criteria:

1. Age between 20-80 years old
2. ASA score I-II
3. receiving labiaplasty

Exclusion Criteria:

1. age < 20 years or older than 80 years
2. ASA score more than II
3. height <152 and >213 cm
4. body mass index > 35 kg/m2
5. allergy to midazolam and lidocaine
6. chronic use of opioid drugs