Postoperative pain control is important in helping patients who underwent abdominal surgery to recover and to live a normal life. There is a method of administering painless injections to relieve postoperative pain. Currently, IV-PCA is mostly used. However, this method has a disadvantage in that the dosage of the opioid-based analgesic is increased, and thus side effects may be concerned. By administering analgesics through an epidural route approached through the thoracic vertebrae rather than intravenous injection, effective post-operative pain control and less side effects can be expected in lesser amounts. This study prospectively compared the pain control effects of IV-PCA and PCEA in patients undergoing resection of hepatobiliary tumors at the National Cancer Center, revealing that PCEA is more effective in alleviating pain after surgery. It has a purpose. In addition, the investigators will investigate and compare clinical outcomes (first fart, dietary progression, postoperative complications, etc.) of the two patient groups and investigate the side effects of PCEA and complications related to the procedure.
