P atients undergoing intracranial surgery are at risk for cerebral ischemia. Therefore, the aim of neuro-anaesthetics is to provide adequate cerebral perfusion during surgery [1]. In patients with increased intracranial pressure (ICP), due to cerebral tumors it is accepted that volatile anaesthetic agents are effective in the protection of cerebral ischemia that may develop due to decrease in systolic arterial pressure (SAP) [2]. Isoflurane's cerebral protection mechanisms include reduction of cerebral metabolic rate (CMR) and metabolic suppression, inhibition of sympathetic activity, reduction of glutamate receptors which are prevent calcium flow, and suppression of excitotoxicity of calcium cascade [3]. It is thought that isoflurane may be secondary to direct vasodilatation or to reduction in CMR by the increase in cerebral blood flow (CBF) reduction [4]. Isoflurane has been reported to cause cerebral protection similar to barbiturates by depressing CMR, and it was shown that it reduce ceree