Programmed Intermittent Bolus Infusion of Thoracic Paravertebral Block for Hepatectomy

Hepatectomy induces moderate to severe postoperative pain. Patient-controlled intravenous analgesia has been used in many medical centers for post-hepatectomy analgesia, but the effects are limited and often cause undesirable adverse effects. Regional Block has been used for postoperative analgesia in many surgeries. Some studies suggest that regional analgesia has an opioid-sparing effect and can reduce the incidence of chronic pain. Also, the programmed intermittent bolus infusion is better than continuous infusion, with less analgesic consumption and fewer adverse effects. Studies on the early and late postoperative analgesia and recovery effects of paravertebral block for open hepatectomy are scarce. Therefore, the investigators aim to conduct a prospective, randomized, subject and assessor-blinded, parallel-group, placebo-controlled study to test the hypothesis that the programmed intermittent bolus infusion of right thoracic paravertebral block reduces postoperative intravenous analgesic use and pain scores and improved patients' satisfaction.