All patients who met the inclusion criteria were randomly divided into four groups, 30 cases in each group, which were lidocaine group 1, lidocaine group 1.5, lidocaine group 2, and the placebo group In lidocaine group 1, lidocaine group 1.5, and lidocaine group 2, 1% lidocaine 1.5 mg/kg was intravenously infused with a micropump after anesthesia induction, and the infusion was completed within 10 minutes according to the ideal body weight, and then continued for 1% lidocaine was infused at 1 mg/kg.h, 1.5 mg/kg.h and 2 mg/kg.h respectively until the end of the operation. In the placebo group, the same volume of normal saline was used instead.

All patients who met the inclusion criteria were randomly divided into four groups, 30 cases in each group, which were lidocaine group 1, lidocaine group 1.5, lidocaine group 2, and the placebo group In lidocaine group 1, lidocaine group 1.5, and lidocaine group 2, 1% lidocaine 1.5 mg/kg was intravenously infused with a micropump after anesthesia induction, and the infusion was completed within 10 minutes according to the ideal body weight, and then continued for 1% lidocaine was infused at 1 mg/kg.h, 1.5 mg/kg.h and 2 mg/kg.h respectively until the end of the operation. In the placebo group, the same volume of normal saline was used instead.Postoperative pain management during the first 72 postoperative hours will involve the use of a PCIA device, which will contain lidocaine 30mg/kg, sufentanil 2 μg/kg, granisetron 12 mg diluted to 200 mL in 0.9 % normal saline. In the placebo group, the same volume of normal saline will be administered during anesthesia. The postoperative PCIA device will contain sufentanil 2 μg/kg, granisetron 12 mg diluted to 200 mL in 0.9% normal saline solution with a total volume of 200 ml. All the background infusions of PCIA will set at 2 ml/h, the bolus volume of each PCIA press is 2 ml and the lockout interval is 15 min.

Inclusion Criteria:

• Age: 18-70 years old
• American Society of Anesthesiologists(ASA) Ⅰ～III
• BMI≤30
• Intended for open liver resection Exclusion criteria：1. Long-term opioid users 2. Patients with contraindications or allergies to any drugs (lidocaine, etc.) used in this study 3. Patients with severe hepatic insufficiency before surgery (defined as total bilirubin>1.46mg/dl), renal insufficiency (glomerular filtration rate <30ml/min/1.73m2 or end-stage renal disease) 4. Associated with severe heart disease (second or third degree atrioventricular block); severe heart failure (ejection fraction <50%); sinus bradycardia; patient 6. Patients who participated in other clinical trials within 3 months before enrollment in the study.

The participants, the anesthesiologist, data collectors, the physicians performing the follow-up, and data analysts will be blinded to the group allocation. Blinding will maintain until the completion of the final analyses.