[Inhaled agents in neuroanaesthesia for intracranial surgery: pro or con]

Abstract

Isoflurane, desflurane and sevoflurane all preserve cerebrovascular carbone dioxide (CO(2)) reactivity. They are all concentration-dependant cerebral vasodilatators and decrease cerebral metabolism. Sevoflurane induces the smallest cerebral vasodilatation and preserve cerebral autoregulation up to 1.5CAM, compared to isoflurane and desflurane which impair it upon 1CAM. Propofol has been compared to inhaled agents. Propofol preserve cerebrovascular CO(2) reactivity, blood flow-metabolism coupling, cerebral autoregulation and has no vasodilatation effect. None of the three inhaled agents induce any clinical relevant increase of intracranial pressure (ICP), but studies were conducted in patients without any intracranial hypertension (ICHT). However, compared to propofol, ICP and brain swelling were higher with inhaled agents, more with isoflurane compared to sevoflurane. Finally, neuroprotective properties have been described in experimental model for all the inhaled agents but clinical proofs are still lacking. In conclusion, for intracranial surgery without any ICHT inhaled agents can be used as a maintenance anesthetic with a preference for sevoflurane. In case of ICHT or a risk of ICHT during the surgery, propofol is preferred for it slightest effect on ICP and cerebral hemodynamic.