Prospective, randomized controlled study to assess the role of dexmedetomidine in patients with supratentorial tumors undergoing craniotomy under general anesthesia.

BACKGROUND

Preliminary data on the perioperative use of dexmedetomidine in patients undergoing craniotomy for brain tumor under general anesthesia 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, alpha 2 adrenoceptor agonist, is used as adjuvant to anesthetic 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 alpha 2 receptors, decreases CSF pressure without ischemic suffering and effectively decreases 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 anesthesia.

METHODS

Fourty patients with CT- scanning proof of supratentorial tumors were classified equally into 2 groups (twenty patients in each group). Group A:--Dexmedetomidine was given as a bolus dose of 1 microg/kg in 20 minutes before induction of anesthesia, followed by a maintenance infusion of 0.4 microg/kg/hr. The infusion was discontinued when surgery ended. Group B:--The patients received similar volumes of saline.

RESULTS

Heart rate and mean arterial blood pressure, decreased significantly in patients of group A (dexmedetomidine group) compared to group B (placebo group) (p-value < 0.05). There was 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 was 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).

CONCLUSION

Continuous intraoperative infusion of dexmedetomidine during craniotomy for supratentorial tumors under general anesthesia maintained the hemodynamic stability, reduced sevoflurane and fentanyl requirements, decreased intracranial pressure, and improved significantly the outcomes.