Effect of OFA in Laparoscopic Gastrectomy

Effect of Opioid Free Anesthesia in Patients Undergoing Laparoscopic Gastrectomy: Subgroup Analysis Based on Psychological Trait

The investigator will examine the effects of opioid free anesthesia in patients undergoing laparoscopic gastrectomy. The investigator expect that opioid free anesthesia will reduce postoperative pain and opioid consumption.

And investigator will analyze the association between postoperative pain and patient's underlying psychological characteristics and pain sensitivity. The investigator anticipate that psychological characteristics and pain sensitivity may be realted to postoperative pain and opioid consumption.

Inclusion Criteria:

• Patients over 19 years who underwent laparoscopic gastrectomy for gastric cancer

Exclusion Criteria:

• Patients with a history of allergic reactions to drugs
• Patients with a history of drug addiction
• Patients with chronic pain who require analgesics
• Patients with cancer other than the stomach
• History of hospitalization for psychiatric disorders
• Patients with sleep apnea
• Preoperative pulse oximetry (SpO2) < 95 %
• Moderate or severe hepatic impairment
• bradycardia (HR<50bpm), hypotension, atrioventricular block, intraventricular or sinus block
• Body mass index over 35 kg/m2
• Blood clotting disorders
• Pregnant/lactating women
• Cognitive impairment
• Unable to read consent form (eg illiterate, foreigner, etc.)