ABSTRACT
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. 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. 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. 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]. 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