In this retrospective study, postoperative pain score, epidural patient controlled analgesia (Epi-PCA) related complications, the risk factors for requirement of rescue analgesics and antiemetics will be evaluated in young and elderly patients, respectively, using fentanyl and ropivacaine-based Epi-PCA during postoperative 48 hours after various surgeries.

Since 2010, A PCA service team in the investigators' hospital have collected multidisciplinary clinical data from all the patients who used epidural-patient controlled analgesia (Epi-PCA) postoperatively in aim of the assessment of clinical outcome. The investigators reviewed the collected data from the patients who had used Epi-PCA for pain control after an elective surgery under general or spinal anesthesia between Sep. 2010 and Nov. 2015. The need for informed consent was waived for this study. For the Epi-PCA, fentanyl and ropivacaine was diluted and administered to the patients according to the clinician's determination.

The data of the PCA regimen which has been decided were recorded and analyzed. Demographic variables including age, sex, body mass index, American Society of Anesthesiologists (ASA) physical status and history of smoking, motion sickness, postoperative nausea/vomiting, hypertension and diabetes mellitus will be analyzed. Anesthesia and surgery-related variables including the duration of anesthesia, the type of anesthesia (general or spinal), laparoscopy and the operation site (categorized in abdominal, thoracic, upper & lower extremities, head & neck, spine and others) will be also analyzed. PCA-related variables including total dose of fentanyl for two days (µg/kg), use of mixed additional analgesics and antiemetics in PCA and discontinuation of PCA will be analyzed. Postoperative variables including the numeric rating scale (NRS, 0-10, 0 = no symptom; 10= unthinkable worst pain) for pain, requirements of rescue analgesics and antiemetics will be analyzed. In addition, the postoperative complications including nausea, vomiting, headache, dizziness, and sedation will be analyzed. All the recorded postoperative variables at post-anesthesia care unit, 6-12, 12-18, 18-24 and 24-48 hrs after anesthesia will be analyzed.

Inclusion Criteria:

• Patients who had used Epi-PCA for pain control after an elective surgery under general or spinal anesthesia between Sep. 2010 and Nov. 2015.

Exclusion Criteria:

• Age < 20 years old,
• Age 40 to 69,
• Routine use of analgesics/antiemetics
• Imperfect data

Collected data from the patients who had used Epi-PCA for pain control after an elective surgery under general or spinal anesthesia between Sep. 2010 and Nov. 2015.