Objective:To evaluate the optimized efficacy of erector spinae plane block (ESPB) with high volume of ropivacaine combined with general anesthesia for patients undergoing thoracoscopic pulmonary surgery.Methods:Sixty American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients of both sexes, aged 18-64 yr, with body mass index of 18-24 kg/m 2, scheduled for elective thoracoscopic pulmonary surgery, were divided into 2 groups ( n=30 each) using a random number table method: ESPB with high volume (40 ml) of 0.4% ropivacaine combined with general anesthesia group (E40 group) and ESPB with conventional volume (20 ml) of 0.4% ropivacaine combined with general anesthesia group (E20 group). Ultrasound-guided ESPB was performed on the operated side before general anesthesia induction in both groups.In E40 group, 0.4% ropivacaine 40 ml was injected.In E20 group, 0.4% ropivacaine 20 ml was injected.Total intravenous anesthesia was applied in both groups.Sufentanil was used for patient-controlled intravenous anesthesia (PCIA) after the end of operation.The PCIA pump was set up with a 2 ml bolus dose (0.04 μg/kg), a 10 min lockout interval and background infusion at a rate of 0.05 μg·kg -1·h -1.The analgesia lasted for 48 h after operation, and the numeric rating scale (NRS) score was maintained ≤ 3.When NRS score ≥ 4, morphine 5 mg was intravenously injected for rescue analgesia.The onset time of block, intraoperative consumption of propofol and remifentanil, time to first pressing the analgesia pump, the first requirement for morphine and the ratio of patients using morphine within 48 h after surgery were recorded.The cumulative consumption of requirement for opioids (effective pressing dose of analgesic pump+ consumption of requirement for morphine) within 12, 24, 36 and 48 h after surgery and satisfaction with analgesia were recorded.The extubation time, length of ICU stay, the first postoperative off-bed time, the chest tube removal time and duration of stay in hospital were recorded.The incidence of intraoperative adverse events (hypertension and hypotension) and postoperative adverse events (dizziness, nausea and vomiting) were recorded. Results:Compared with E20 group, the onset time of block was significantly shortened, the cumulative consumption of requirement for opioids within 24, 36 and 48 h after surgery was decreased, the ratio of paitents using morphine within 48 h after surgery was decreased, time to first pressing the analgesia pump and the first requirement for morphine were prolonged, satisfaction with analgesia score was increased, and the first postoperative off-bed time and the chest tube removal time were shortened in group E40 ( P<0.05). There was no significant difference in the incidence of adverse events between the 2 groups ( P>0.05). Conclusion:Compared with ESPB with the conventional volume of ropivacaine combined with general anesthesia, ESPB with the high volume of ropivacaine combined with general anesthesia can reduce the postoperative consumption of opioids, and prolong the duration of effective analgesia, which are helpful for postoperative rapid recovery without increasing the development of adverse events in patients undergoing thoracoscopic pulmonary surgery.