PROSPECTIVE, RANDOMIZED STUDY TO ASSESS THE ROLE OF DEXMEDETOMIDINE IN PATIENTS WITH SUPRATENTORIAL TUMORS UNDERGOING CRANIOTOMY UNDER GENERAL ANAESTHESIA

Background: Preliminary data on the perioperative use of dexmedetomidine in patients undergoing craniotomy for brain tumor under general anaesthesia indicate that the intraoperative administration of dexmedetomidine is opioid-sparing, results in less need for antihypertensive medication, and may offer greater hemodynamic stability at incision and emergence. Dexmedetomidine, α 2 adrenoceptor agonist used as adjuvant to anaesthetic agents. Relatively recent studies have shown that dexmedetomidine is able to decrease circulating plasma norepinephrine and epinephrine concentration in approximately 50%, decreases brain blood flow by directly acting on post-synaptic α 2 receptors, decreases CSF pressure without ischemic suffering and effectively decrease brain metabolism and intracranial pressure and also, able to decrease injury caused by focal ischemia. Purpose: This prospective, randomized, double-blind study was designed to assess the perioperative effect of intraoperative infusion of dexmedetomidine in patients with supratentorial tumors undergoing craniotomy under general anaesthesia. Methods: Forty patients with CT- scanning proof of supratentorial tumors. The patients were classified equally into 2 groups (twenty patients in each group). Group A: - The dexmedetomidine was given as a bolus dose of 1 μg/kg in 20 minutes before induction of anaesthesia, followed by a maintenance infusion of 0.4 μg/kg/hr. The infusion was discontinued when surgery ended. Group B: - The patients received similar volumes of saline. Results: The heart rate and mean arterial blood pressure, decreased in patients of group A (dexmedetomidine group) more than group B (placebo group) with significant statistical differencebetween the two groups (P-value 0.05). No significant statistical difference between the two groups regarding the central venous pressure and arterial partial pressure of Carbon Dioxide (P-value 0.05). The intraoperative end-tidal sevoflurane (%) in patients of group A less than in patients of group B (P-value 0.05).The intracranial pressure decreased in patients of Group A more than group B (P-value 0.05). The Glasgow coma scale (GCS) improved in patients of group A and deteriorated in patients of Group B with significant statistical difference between the two groups (P-value 0.05). The Total fentanyl requirements from induction to extubation of patients increased in patients of group B more than in patients of group A (P-value 0.05). The total postoperative patients requirements for antiemetic drugs within the 2 hours after extubation decreased in patients of group A more than group B (P-value 0.05). The postoperative duration from the end of surgery to extubation decreased significantly in patients of group A more than group B (P-value 0.05). The total urine output during the duration from drug administration to extubation of patients increased in patients of group A more than group B (P-value 0.05). Conclusions: Continuous intraoperative infusion of dexmedetomidine during craniotomy for supratentorial tumors under genera-1 anaesthesia maintained the haemodynamic stability, reduced sevoflurane and fentanyl requirements, decreased intracranial pressure, and improved significantly the outcomes.