The external oblique intercostal (EOI) plane block is a novel approach upper abdominal wall analgesia. The EOI plane block can provide dermatomal sensory blockade of T6-T10 at the anterior axillary line and T6-T9 at the midline. It may be used for postoperative analgesia in obese patients because it is superficial and rapidly identifiable and performed in the supine position. the aim of this study is to investigate the postoperative analgesic efficacy of external oblique intercostal plane block in obese patients undergoing laparoscopic sleeve gastrectomy.

Researchers will compare the external oblique intercostal plane block group with control group to see if the EOI plane block is effective for postoperative analgesia in patients undergoing sleeve gastrectomy.

Patients scheduled for elective laparoscopic sleeve gastrectomy will be separated into 2 groups: Control Group and External Oblique Intercostal Plane Block Group. Patients in Control Group will be received patient controlled analgesia with morphine for postoperative analgesia. Patients in External Oblique Intercostal Plane Block Group will be performed bilateral External Oblique Intercostal Plane Block before the surgery and received patient controlled analgesia with morphine for postoperative analgesia. Morphine consumption for first postoperative 24 hours, visual analog scale scores, time to need for first rescue analgesia, amount of rescue analgesic drug, incidence of postoperative nausea and vomiting will be recorded.

Inclusion Criteria:

• Age between 18 and 80 years
• Patients with American Society of Anesthesiology (ASA) physical status II-III
• Patients scheduled for a laparoscopic sleeve gastrectomy

Exclusion Criteria:

• Allergy to local anesthetics
• Coagulopathy
• Skin infection at the EOI Plane Block area
• Advanced hepatic or renal failure
• Chronic pain syndromes
• Alcohol or drug abuse
• Severe pulmonary and/or cardiovascular disease
• Psychiatric disorders