Laparoscopic Sleeve Gastrectomy Surgery and External Oblique Intercostal Block

Bilateral Ultrasound-guided External Oblique Intercostal Block for Postoperative Analgesia in Patients Undergoing Laparoscopic Sleeve Gastrectomy Surgery: A Prospective Randomized Controlled Study

In obese patients, adequate pain relief in the postoperative period is an important parameter that affects patient comfort and hospital stay. Increasing patient comfort and recovery quality can be achieved by avoiding undesirable effects such as nausea, vomiting, and analgesia. This study aimed to evaluate the impact of the external oblique intercostal block postoperative acute pain scores and opioid consumption in the first 24 hours after laparoscopic sleeve gastrectomy surgery.

Adequate pain control in laparoscopic surgeries is associated with reduced postoperative opioid administration, faster mobilization, faster recovery, and shorter hospital stays. Intraoperative nerve blocks using local anesthetics have been shown to improve postoperative pain in various abdominal surgeries, both open and laparoscopic. Laparoscopic bariatric procedures are most often associated with moderate to severe visceral pain from surgical manipulation of the stomach and intestine. Combined regional and general anesthesia reduces surgical stress responses by interrupting pain transmission signals, which facilitates pain control, reduces opioid consumption, and improves patient postoperative satisfaction. Ultrasound-guided fascial plane blocks have been rapidly included in regional anesthesia applications as an alternative to neuraxial techniques in recent years and include injection into a tissue plane to provide analgesia in various anatomical areas. The external oblique intercostal block (EOIB) represents an essential modification of the fascial plane block techniques that can consistently cover the upper lateral abdominal wall. The EOIB block has easily identifiable sonographic points. The study aims to investigate the effects of the EOIB on postoperative pain in morbidly obese patients who will undergo laparoscopic sleeve gastrectomy by comparing it with the control group. It is seen that there are not enough studies on EOIB in the literature. Our study, which the investigators think will contribute to the literature, was planned as a prospective, randomized, controlled, single-blind, parallel-group study. Patients will be divided into two groups: Group EOIB : A bilateral EOIB (60 ml 0.25% bupivacaine + 1:400.000 adrenaline) will be performed. In addition, IV morphine-PCA will be applied postoperatively for 24 hours. Group Control: Patients in this group will not receive any block. IV morphine-PCA will be applied postoperatively for 24 hours.

A block randomization list will be created by a doctor who does not participate in patient follow-up using a web-based program, 'Research Randomizer (Urbaniak and Plous, 2013)'.

Sealed opaque envelopes containing study participation numbers will be used to assign each patient. A researcher not involved in patient follow-up will use the web-based "Research Randomizer" (Urbaniak and Plous 2013) tool to give each participation number to a random group with a 1:1 ratio. A nurse not an active investigator in the study will have each participant choose an envelope containing the study participation number. They will inform the anesthetist administering the block/blocks about which group the patient is in immediately before administration. Researchers, surgeons, and nurses will not be aware of the randomization of groups.

A bilateral EOIB (60 ml, %0.25 bupivacaine, totally) + IV morphine patient-controlled analgesia (PCA)

Bilateral ultrasound-guided EOIB (total of 60 ml, %0.25 bupivacaine) will be performed + IV morphine PCA Multimodal analgesia : Patients are administered iv tenoxicam 20mg and tramadol 100 mg after induction of general anesthesia, and iv paracetamol 1 gr and 0.05 mg/kg, ideal body weight (IBW), iv morphine will be administered. End of the surgery, hyoscine-N-butyl bromide will be administered. Postoperative analgesia: iv paracetamol 1gr every 8 hours and IV PCA of 0,5mg/ml morphine (the bolus dose is 20 µg/kg, the lock-in time of 6-10 minutes, the 4-hour limit is adjusted to be 80% of the calculated total amount). In cases where rescue analgesia is required (NRS score ≥4), 50 mg of meperidine is administered to patients. Patients are routinely administered ondansetron 8 mg IV 20 minutes before extubation for postoperative nausea and vomiting prophylaxis.

Patients in this group will not be performed interfacial plane blocks. Multimodal analgesia : Patients are administered iv tenoxicam 20mg and tramadol 100 mg after induction of general anesthesia, and iv paracetamol 1 gr and 0.05 mg/kg (IBW) iv morphine will be administered. End of the surgery, hyoscine-N-butyl bromide will be administered. Postoperative analgesia: iv paracetamol 1gr every 8 hours and IV PCA of 0,5mg/ml morphine (the bolus dose is 20 µg/kg, the lock-in time of 6-10 minutes, the 4-hour limit is adjusted to be 80% of the calculated total amount). In cases where rescue analgesia is required (NRS score ≥4), 50 mg of meperidine is administered to patients. Patients are routinely administered ondansetron 8 mg IV 20 minutes before extubation for postoperative nausea and vomiting prophylaxis.

Morphine consumption in the first 24 hours after surgery will be measured. Patients can request opioids via a PCA device when their NRS score is≥ 4.

Pain status at rest and while activity will be assessed by NRS score at 0, 3, 6, 12, 18, and 24 hours after surgery. The NRS is an 11-point numeric scale that ranges from 0 to 10.

Patients' pain management satisfaction and quality will be evaluated using the Revised American Pain Society Patient Outcome Questionnaire (APS-POQ-R) -Turkish Version.

The severity of postoperative nausea and vomiting (PONV) will be assessed using a descriptive verbal rating scale at 0, 3, 6, 12, 18, and 24 hours after extubation. If a score of 3 or more, ondansetron 4 mg IV will be administered and will repeat after 8 hours if required. The PONV scale is 0 = no nausea; 1 = slight nausea; 2 = moderate nausea; 3 = vomiting once; and 4 = vomiting more than once.

The remifentanil consumption will be recorded from anesthesia induction until the patient is referred to the recovery unit, up to 150 minutes.

The number of patients has any complications -directly related to the block or the drug used in the block- will be recorded

The heart rate was recorded preoperatively, one minute after the induction, and every 15-30 minutes until the patient was referred to the recovery unit.

Time Frame: The heart rate was recorded preoperatively, one minute after the induction, and every 15-30 minutes until the patient was referred to the recovery unit, up to 180 minutes.

The mean arterial pressure was recorded preoperatively, one minute after the induction, and every 15-30 minutes until the patient was referred to the recovery unit.

The mean arterial pressure was recorded preoperatively, one minute after the induction, and every 15-30 minutes until the patient was referred to the recovery unit, up to 180 minutes.

Inclusion Criteria: Age between18-65 years American Society of Anesthesiology score II-III Body mass index (BMI) > 35 kg/m2 Patients who will sign the informed consent form Exclusion Criteria: History of opioid use for more than four weeks Chronic pain syndromes Patients with a history of local anesthetic or opioid allergy, hypersensitivity Severe cardiac, hepatic, and renal disease Alcohol and drug addiction Conditions where regional anesthesia is contraindicated Failure in the dermatomal examination performed after the block Patients with a STOP-BANG score ≥5

Saber AA, Lee YC, Chandrasekaran A, Olivia N, Asarian A, Al-Ayoubi S, DiGregorio R. Efficacy of transversus abdominis plane (TAP) block in pain management after laparoscopic sleeve gastrectomy (LSG): A double-blind randomized controlled trial. Am J Surg. 2019 Jan;217(1):126-132. doi: 10.1016/j.amjsurg.2018.07.010. Epub 2018 Aug 1.

Elsharkawy H, Kolli S, Soliman LM, Seif J, Drake RL, Mariano ER, El-Boghdadly K. The External Oblique Intercostal Block: Anatomic Evaluation and Case Series. Pain Med. 2021 Nov 26;22(11):2436-2442. doi: 10.1093/pm/pnab296.

White L, Ji A. External oblique intercostal plane block for upper abdominal surgery: use in obese patients. Br J Anaesth. 2022 May;128(5):e295-e297. doi: 10.1016/j.bja.2022.02.011. Epub 2022 Mar 3. No abstract available.

Coskun M, Yardimci S, Arslantas MK, Altun GT, Uprak TK, Kara YB, Cingi A. Subcostal Transversus Abdominis Plane Block for Laparoscopic Sleeve Gastrectomy, Is It Worth the Time? Obes Surg. 2019 Oct;29(10):3188-3194. doi: 10.1007/s11695-019-03984-4.