Cerebral Autoregulation in Patients With Aneurysmal SubArachnoid Haemorrhage

The purpose is, in patients with aneurysmal subarachnoid haemorrhage in the early phase after ictus, to examine the following: 1. The effect of spontaneous and induced changes on the brain's static and dynamic autoregulation calculated by transcranial Doppler (TCD), ICP and MAP (primary purposes) and ICP and PbtO2; 2. The effect of mild hyper- and hypocapnia as well as of mild hyper- and hypoxia on the brain's static and dynamic autoregulation, ICP and PbtO2; 3. The relationship between brain autoregulation, mild hyper- and hypocapnia, as well as of mild hyper- and hypoxia and metabolism in microdialysate on the one hand and the occurrence of DCI during hospitalization and poor neurological outcome one year after ictus on the other.