Erector Spinae Plane Block Versus Opioid Based General Anesthesia During Laparoscopic Bariatric Surgery

The investigators hypothesized that, erector spinae plane block will provide good analgesia for patients undergoing laparoscopic bariatric surgery with less complication compared to opioid based general anesthesia. The visual analogue scale (VAS) will be explained clearly to all participants before conduction of anesthesia. All the drugs will be calculated according to the ideal body weight (IBW).A low-frequency (2-5 MHz) curved array ultrasound probe (Mindray®, China) will be used. In the 1st group: bilateral ultrasound-guided erector spinae plane block will be performed under complete aseptic conditions in the lateral position at T7 vertebrae and before induction of general anesthesia. An 8-cm echogenic 22-G block needle will be inserted in-plane. A total of 20 ml of local anesthetic solution (20 ml bupivacaine (Sunnypivacaine, Sunny pharmaceutical, Egypt) 0.25%) will then be injected into the erector spinae plane. This procedure will be repeated on the contralateral side taking care not to exceed the maximum recommended doses (2 mg/kg of IBW for bupivacaine). In the 2nd group: the investigator will give intravenous nalbuphine in a dose of 2mg /kg according to ideal body weight after induction of general anesthesia. All participants will be given 1 gram of intravenous paracetamol (15 mg/Kg), together with 4 mg ondansetron 10 min prior to the end of surgery for postoperative nausea and vomiting prophylaxis. Intraoperatively, any increase in heart rate and/or arterial blood pressure 10 min after intubation by more than 20% of baseline values in response to surgical stimulus or thereafter throughout the whole operation will be managed by intravenous administration of fentanyl 0.5 µg/Kg. VAS score will be assessed 30 min after extubation and when the VAS score exceeded 4/10, rescue analgesia in the form of IV nalbuphine 5 mg will be administered. Another dose of rescue analgesia can be given in the post anesthesia care unit (PACU) if the VAS still more than 4 after 60 min of extubation. If still high, Ketorolac 60 mg will be given by intravenous infusion.