Sommer B, et al. - This study assessed the effect of early magnesium sulfate (MgSO₄) administration on local cerebral microcirculation during microsurgical clipping of subarachnoid hemorrhage (SAH)-related aneurysms. Early intraoperative administration of MgSO₄ in patients with SAH resulted in an increased cerebral blood flow. Data also indicated that this technique is feasible for continuous real-time monitoring of cerebral microcirculation, using a non-invasive laser-Doppler spectrophotometry system.