Quantification of dynamic cerebral autoregulation
A description of the method to calculate dynamic CA in anaesthetised patients was published earlier by our group.The covariance between input and output signals can be expressed as coherence. This is the portion of MCAIn awake individuals, lower frequency dynamic CA can be assessed easily because resting sympathetic activity results in a rhythmic variation in vascular tone, which translates into MAP oscillations of ∼0.1 Hz (known as Mayer waves).In this study, we applied our recently introduced method for mimicking Mayer waves during anaesthesia by adjusting the breathing frequency of the positive pressure mechanical ventilation to 6 breaths min