Epidural PCA (patient controlled analgesia) for post-operative pain management are effective analgesic method. It is widely used in the postoperative pain management for decades.

PCA pumps typically set a fixed basal infusion rate to infuse the analgesics at a constant rate per every hour (conventional mode). In contrast, the newly developed computer-integrated patient-controlled analgesia (CIPCA) mode increases or decreases the basal infusion rate with the use of the patient's bolus button. The CIPCA mode sets the basal infusion rate, the increase / decrease rate of basal rate, and the increment / decrement interval. If the patient presses the bolus button within the set time interval, the set infusion rate is increased because the analgesic is more required. If the bolus button is not pressed during the set time interval, the infusion rate is decreased. Therefore, it can be said that it is an effective method to control the dose of analgesic agent more sensitively to changes in patient's needs and pain.

Inclusion Criteria:

1. elective open gastrectomy due to stomach cancer
2. ASA classification Ⅰ-Ⅲ

Exclusion Criteria:

1. hematologic clotting defect
2. sepsis
3. distance metastasis
4. PCA drug (fentanyl, Ropivacaine) allergy
5. Patients who can not read the consent form or are not fluent in Korean (illiterate, foreigner)
6. pregnant, lactating women