Delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage (aSAH) results from a complex combination of macro- and microvascular processes. Besides cerebral vasospasms (CVS), DCI is caused by microthrombosis, neuroinflammation, microvascular dysfunction and cortical spreading depolarization.The glycocalyx plays an essential role in regulation of inflammation, oxidative stress and thrombosis, and could be involved in the pathophysiology of DCI. This study is a single-center prospective observational pilot (phase 1) and correlation (phase 2) study recruiting patients with an aneurysmal subarachnoid hemorrhage. The primary aim of the study is to evaluate the feasibility of performing measurements of the glycocalyx using side-stream darkfield (SDF) imaging sublingually and on the conjunctiva, and by sampling blood for analysis of markers of glycocalyx shedding. Moreover, the objective is to determine characteristic Doppler waveform morphologies in DCI patients by means of thorough analysis of transcranial Doppler (TCD) measurements. The secondary objective is to determine whether changes in glycocalyx integrity correlate with the development of DCI and whether these changes are associated with increased inflammation and with variation in TCD signals. Finally, changes in glycocalyx integrity, in TCD waveform morphology and in levels of inflammatory markers will be correlated with patient outcome at 6 weeks and 6 months after ictus.