Effect of mannitol on intracranial pressure-volume status and cerebral haemodynamics in brain oedema

Continuous measurement of CBV and CBF by means of laser-Doppler flowmetry was performed to analyze the temporal profile of cerebrovascular response to water accumulation in an infusion model of brain oedema. Using this method, the effect of mannitol on CBV was also examined to determine how mannitol improves the intracranial pressure-volume relationship. The results show that: (1) The presence of an oedema generator elicits a continuous reduction of CBV and a transient reduction of CBF. With cessation of this mechanical force of oedema production, CBV and CBF return to control levels. (2) Mannitol increases CBV and PVI. The improvement of PVI might be due to an increase in CBV as well as ICP reduction.