The goal of this clinical trial is to compare the effects of Opioid Free Anesthesia (OFA) with and without volatile anesthetics (in this case desflurane) in patients undergoing bariatric surgery. The main question it aims to answer :

-Will there be a difference in the perioperative stress between patients receiving OFA with and without desflurane?

Participants will undergoing sleeve gastrectomy or gastric by pass, will be administered OFA with and without desflurane and blood tests (cortisole, ACTH,dopamine, PRL, adrenaline, noradrenaline, lactate) will be collected perioperatively to compare stress in the two groups.

Inclusion Criteria:

• Signed Informed Consent
• ASA II-III
• Morbid obesity confirmed diagnosis and approval for surgical treatment
• Laparoscopic sleeve gastrectomy (LSG) or Gastric By pass (R-Y By pass /SASI/SADI AND one anastomosis by pass )
• Preop respiratrory assessment conducted
• Adequate organ and bone marrow function

Exclusion Criteria:

• Patients declining or withdrawing consent
• Patients unsuitabe with regards to compliance to treatment, according to the researcher's assessment
• Bradycardia, AV block, , postural hypotension
• QTcF>470msec
• Known allergy or hypersensitiity to any of the medications administered
• Stop-BANG score >6
• Intraoperative administration of more than 8mg of prednisolone or equivalent
• Patients who have received corticosteroids for durations >3 weeks at any point in their lifetime
• Participation in other clinical trial for experimental product administered post operatively
• Diagnosis of depression