Non-opioid Anesthesia Based on Thoracic Paravertebral Block During Laparoscopic Sleeve Gastrectomy

Comparison of Opioid-based Anesthesia, Opioid-free Anesthesia Based on Intravenous Drugs and Opioid-free Anesthesia With Thoracic Paravertebral Block, in Patients Undergoing Laparoscopic Gastric Bypass Surgery for Obesity

Regional anesthesia is a technique in which a local anesthetic is injected near a nerve or spinal cord to block sensation, motor stimulation, and pain. In this study, an ultrasound-guided paravertebral block will be used, with careful consideration of all positive and negative factors and possible complications. A thoracic paravertebral block is performed by inserting a needle into the intercostal spaces on the back, approximately 4 cm lateral to the spine. Many studies support excellent pain control with this technique, during and after surgery in thoracic and abdominal surgery. Investigators aim to achieve faster patient mobility after surgery, rapid recovery of bowel function, reduced nausea and vomiting, and maximum pain control. The use of opioids, which can additionally cause respiratory suppression and drowsiness, is avoided.

At any time in case of need to switch from laparoscopic to open surgery, equally adequate anesthesia and postoperative analgesia are ensured without the need to change the approach to the same. In this study, the basic scientific assumption (hypothesis) of the researchers is that non-opioid anesthesia with thoracic paravertebral block provides adequate pain control during and long-term after the surgical procedure, without the side effects of opioid anesthesia.

The main goal of the study is to determine which type of anesthesia results in the best pain control and most significantly reduces complications of anesthesia and surgery in overweight patients who are scheduled for laparoscopic longitudinal gastrectomy and partial/total gastrectomy.

Morbid obese patients scheduled for laparoscopic sleeve gastric resection need specific care during surgery and post-surgery. Postoperative pain management of these patients after this type of surgery is a challenge because of the high prevalence of nausea, vomiting, and higher risk of respiratory depression in obese patients, making the use of opioids undesirable. Various techniques have been used during and after surgery to control moderate to severe pain for early mobilization: OFA (opioid-free anesthesia) based on intravenous use of dexmedetomidine, ketamine, and lidocaine, or OBA (opioid-based anesthesia) in combination with regional anesthesia, to reduce the use of opioids. Regional anesthesia can be used as an additional modality of analgesia within OFA (opioid-free anesthesia) or opioid-based anesthesia (OBA), which either completely avoid the use of opioids or significantly reduce them. Investigators will compare opioid-based general anesthesia (OBA group) as the standard of anesthesia for bariatric surgery with intraoperative opioid- free anesthesia based on thoracic paravertebral block (TPVB group) and intraoperative opioid-free anesthesia based on intravenous dexmedetomidine, ketamine, and lidocaine (OFA group). The primary objective is to compare pain levels as measured by the 0-10 NRS and to compare opioid and analgesic consumption in the perioperative period.

Inclusion Criteria:

-. patients with a prior history of treatment by a multidisciplinary obesity team scheduled for laparoscopic sleeve gastrectomy (LSG)

• body mass index of 30 kg/m² or greater
• patients classified as ASA status 2-3.

Exclusion Criteria:

• allergies to the intended medications
• patient refusal
• uncontrolled psychiatric disorders
• intracranial pathology
• cerebrovascular damage
• any factors impairing effective communication

Additional Exclusion Criteria:

1. For patients receiving thoracic paravertebral block (TPVB):

   - the presence of infection at the puncture site

2. For the OFA group:

   • 2nd or 3rd-degree atrioventricular block
   • bradycardia with a heart rate below 50 beats per minute
   • coronary artery disease,
   • cardiomyopathy.