Comparison of Opioid Based and Opioid Free Anaesthesia in Transsphenoidal Surgery

Opioid Free Anesthesia (OFA) is a technique where no intraoperative opioid is administered during the anesthetic management. Opioid free anesthesia is usually achieved through sympatholysis, analgesia, and anesthesia with dexmedetomidine and analgesia with low dose ketamine. In addition paracetamol and other non-steroidal anti inflammatory drugs (NSAIDS) may be used as adjuncts to the multi-modal pain regimen.

Dexmedetomidine, a highly selective agonist of the alpha2 adrenergic receptor, has many clinical benefits, such as sedation, analgesia, preventing unwanted stress responses and low risk of respiratory depression. Because of concern that opioids might cause perioperative respiratory depression, substitution with dexmedetomidine will be helpful with its analgesic and sympatholytic properties. Dexmedetomidine has shown to reduce minimum alveolar concentration (MAC) of inhalational anesthetics and the requirement of perioperative opioid by 30-50%. In neurosurgical patients, dexmedetomidine is helpful in maintaining intracranial pressure (ICP) and intraoperative hemodynamic stability, especially during intubation and extubation. It can allow for faster awakening and thus an earlier neurological examination by decreasing necessary volatile agent and opioid doses.

Ketamine, an N-methyl-d-aspartate(NMDA) antagonist, blunts central pain sensitization at sub-anesthetic doses (0.5 mg/kg or less) and has been studied extensively as an adjunct for perioperative analgesia. Sub-anesthetic ketamine improves pain scores and reduces perioperative opioid consumption in a broad range of surgical procedures.Recent literature has suggested that adjuvant ketamine administration in mechanically ventilated patients has no cerebrovascular effects.

The present study has been planned to compare the effect of opioid free anesthesia using dexmedetomidine and ketamine with opioid based anesthesia using fentanyl in maintaining the intraoperative hemodynamic stability and recovery characteristics in patients undergoing TSS of pituitary tumors.

Inclusion criteria

• patients suffering significant pituitary adenocarcinomas posted for transsphenoidal resection of tumor
• age group between 18 to 65 yr
• Both males and females
• ASA physical status 1 to 2

Exclusion criteria

• pts taking opioid for chronic pain
• Pregnant or nursing woman
• Preoperative GCS <15
• HR<50/min
• Patients with allergies to study medication
• Patients with psychiatric disorder
• Patients with unstable cardiorespiratory disorder
• Patients with hepatic and renal insufficiency