Laser Doppler Flowmeter (LDF) is a new, reliable and simple method to monitor regional Cerebral Blood Flow (RCBF). Our group began to perform intraoperative LD recordings in 1986. Recently, the advent of new special probes and the use of computer techniques, allowed two important improvements: an easy and safe postoperative LDF monitoring in Intensive Care Unit, the simultaneous (intra- and postoperatively) acquisition of other signals on a computer: i.e. ICP, SAP, CVP, and end-Tidal CO2.