Standardized Anesthesia Protocol
Before anesthesia, all patients were delivered to the pre-anesthesia room for the arterial intubation and ultrasound-guided PNB. In brief, TAPB and QLB were performed by an experienced anesthesiologist who was blinded to the trial. By using a convex array probe (Sonosite Micromaxx, Bothell, WA, USA) with a frequency of 2–5 MHz, bilateral TAPB or QLB was completed with the diffusion of 30 ml of 0.33% ropivacaine (including dexmedetomidine 1 ug/kg) or normal saline into the fascia plane.A standardized anesthesia protocol was conducted to all patients. Briefly, perioperative administration of dexmedetomidine was achieved by a bolus infusion at 2 μg/kg/h for 15 min and a continuous infusion at 0.4 μg/kg/h during the surgery, as well as the subsequent patient-controlled intravenous analgesia (PCIA) device after surgery. General anesthesia induction was accomplished with midazolam (0.025 mg/kg), propofol (1.5 mg/kg), cisatracurium (0.2 mg/kg), and remifentanil (2 μg/kg). General anesthesia was maintained with sevoflurane inhalation as well as continuous infusion of remifentanil (5–15 μg/kg/h) and cisatracurium (0.1–0.2 mg/kg/h). The doses of all intravenous anesthetics were calculated based on the ideal body weight for each patient. During the operation, vasoactive agents were applied to maintain the mean arterial pressure (MAP) and heart rate (HR) within a range of 20% more or less than the baseline. Parecoxib 40 mg and nalbuphine 10 mg were also used as analgesia complement. The same surgeon team performed all the surgical procedures by using five ports technique.