PROPOFOL IN NEUROSURGICAL ANESTHESIA

The quality, result, and prognosis of neurosurgery relies heavily on t he anaesthetic technique. Many different classes of drugs have been us ed during neurosurgical anaesthesia. This article reviews the use of i ntravenous (IV) propofol as an alternative to volatile anaesthetic tec hniques. Anaesthesia requirements for neurosurgical procedures are ela borated upon in the first part of the article. The priority of neuroan aesthesia is to preserve neuronal function by avoiding complications s uch as hypoxia, hypercarbia, and cardiovascular instability. Thereafte r, the chosen anaesthetic technique should minimally interfere with ce rebral autoregulation and CO2 responsiveness, while brain relaxation i s encouraged by decreasing the cerebral metabolic rate for oxygen (CMR O(2)) and cerebral blood flow (CBF). In addition, the anaesthetic tech nique should be associated with rapid and predictable recovery in the operating theatre in order to allow early evaluation of the surgery. T he second part of the article describes IV techniques for neurosurgery as an alternative to volatile anaesthetics, all of which increase CBF , cerebral blood volume, and intracranial pressure (ICP) in a dose-rel ated manner and diminish cerebral autoregulation and interfere with ce rebrovascular CO2 reactivity. Nitrous oxide has a stimulant effect on cerebral metabolism and is associated with an increase in CBF. On the other hand, all IV agents except ketamine are associated with decrease s in CMRO(2) and are cerebral vasoconstrictors. For this reason, it is rational to use them for the induction and maintenance of anaesthesia for neurosurgery as part of a total IV anaesthetic technique. The thi rd part of the article focuses on propofol as the newest representativ e of IV anaesthetics. It is a sedative-hypnotic agent that has a pharm acokinetic-dynamic profile ideally suited for continuous infusion. Pro pofol reduces ICP, CBF, and CMRO(2). Animal models have suggested the possibility of cerebral protection. The responsiveness of the cerebral circulation to alterations in arterial blood pressure is maintained. Evaluating propofol for major neurosurgery demonstrated good quality a nd depth of anaesthesia, excellent brain relaxation, and minimal surgi cal bleeding. In conclusion, total IV anaesthesia with propofol has pr oven to be a valid alternative to conventional thiopentone-isoflurane anaesthesia for intracranial surgery.