Premedication: pantoprazol 40mg i.v. Preoperative TPVB is executed at the Th5, Th7, and Th9 levels bilaterally. The skin at each level are infiltrated with 1.5 ml of 1% lidocaine. Subsequently, 10 ml of 0.33% levobupivacaine, combined with 1.33 mg of dexamethasone and 40 mcg of adrenaline, is injected at each level and flushed with 1 ml of 5% glucose. In the operating room a induction is carried out with propofol administered at a dosage of 2-2.5 mg/kg of ideal body weight (IBW) and rocuronium at 0.8-1 mg/kg of IBW. Anesthesia is maintained with an infusion of propofol at 100 mcg/kg of total body weight (TBW) per minute, with adjustments made to achieve a targeted BIS value between 40-60. Intraoperative pain management includes metamizole (2.5 g) and acetaminophen (1 g). Prophylaxis of PONV is dexamethasone 8 mg previously administered within the thoracic paravertebral block, with intraoperative administration of 10 mg metoclopramide.

Completely opioid-free interventions.

Used in thoracic paravertebral block: 10 ml of 0.33% levobupivacaine, combined with 1.33 mg of dexamethasone and 40 mcg of adrenaline, is injected at each level (six levels, at the Th5, Th7, and Th9 levels bilaterally; a total of 200 mg of levobupivacaine, 8 mg of dexamethasone and 240 mcg of adrenaline).

Used in thoracic paravertebral block: 10 ml of 0.33% levobupivacaine, combined with 1.33 mg of dexamethasone and 40 mcg of adrenaline, is injected at each level (six levels, at the Th5, Th7, and Th9 levels bilaterally; a total of 200 mg of levobupivacaine, 8 mg of dexamethasone and 240 mcg of adrenaline).

A pre-prepared 50 ml syringe is utilized, containing 400 mcg of dexmedetomidine (4 ml), 50 mg of S-ketamine (2 ml), 400 mg of 2% lidocaine (20 ml), and 0.9% NaCl to a total volume of 40 ml. Anesthesia is commenced with the infusion from syringe 1 over a 10-minute period at a rate of 15 ml/hour. The anesthetic mixture was maintained at a rate of 5-10 ml per hour.

A pre-prepared 50 ml syringe is utilized, containing 400 mcg of dexmedetomidine (4 ml), 50 mg of S-ketamine (2 ml), 400 mg of 2% lidocaine (20 ml), and 0.9% NaCl to a total volume of 40 ml. Anesthesia is commenced with the infusion from syringe 1 over a 10-minute period at a rate of 15 ml/hour. The anesthetic mixture was maintained at a rate of 5-10 ml per hour.

A pre-prepared 50 ml syringe is utilized, containing 400 mcg of dexmedetomidine (4 ml), 50 mg of S-ketamine (2 ml), 400 mg of 2% lidocaine (20 ml), and 0.9% NaCl to a total volume of 40 ml. Anesthesia is commenced with the infusion from syringe 1 over a 10-minute period at a rate of 15 ml/hour. The anesthetic mixture was maintained at a rate of 5-10 ml per hour.

Following three-minute preoxygenation, sufentanil (5 to 15 micrograms), propofol (1 to 2 mg/kg ideal body weight), and rocuronium (0.8 to 1 mg/kg ideal body weight) are administered intravenously during induction of anesthesia. Anesthesia is sustained with sevoflurane maintained at 0.6-1.3 MAC. Sufentanil is added at the assessment of the anesthesiologist in the operating room.

Patients scheduled for laparoscopic sleeve gastrectomy will be anesthetized without the use of opioids, with general anesthesia and pain blockade using a thoracic paravertebral block

Patients scheduled for laparoscopic sleeve gastrectomy will be anesthetized with opioids and general anesthesia

Patients who are scheduled for laparoscopic gastrectomy will be anesthetized without the use of opioids and under general anesthesia, with analgesia by intravenous administration of dexmedetomidine, ketamine and lidocaine.

Patients are positioned prone, with the identification of the 1st rib achieved using a convex XX Hz ultrasound probe. The left and right transverse processes of the 5th, 7th, and 9th thoracic vertebrae are marked accordingly. TPVB is executed in a paramedian sagittal oblique scan utilizing an in-plane needle insertion approach at the Th5, Th7, and Th9 levels bilaterally. An insulated echogenic needle, sized between 10-15 cm and 22-20 G, is employed. The skin and subcutaneous tissue at each level are infiltrated with 1.5 ml of 1% lidocaine.

Ultrasound guidance combined with nerve stimulation (dual monitoring) is utilized at each corresponding paravertebral space. Verification of the paravertebral space is established through visualization of pleural displacement, as observed via the ultrasound probe following the injection of 1 ml of 5% glucose, as well as via a motor response at a current intensity of 0.3-0.5 mA.

During the application of the thoracic paravertebral block, verification of the distance of the insulated echogenic needle tip from the thoracic spinal nerve is monitored using via a motor response at a current intensity of 0.3-0.5 mA.

To prevent postoperative nausea and vomiting (PONV), patients receive dexamethasone (8 mg) and metoclopramide (10 mg) intraoperatively

To prevent postoperative nausea and vomiting (PONV), patients receive dexamethasone (8 mg), ondansetron (4 mg), and metoclopramide (10 mg) intraoperatively.

To prevent postoperative nausea and vomiting (PONV), patients receive dexamethasone (8 mg) and thiethylperazine (6.5 mg) intravenously.

To prevent postoperative nausea and vomiting (PONV), patients receive intraoperatively dexamethasone (8 mg), ondansetron (4 mg), and metoclopramide (10 mg) intravenously.