Vasospasm is a current complication after aneurysmal subarachnoid hemorrhage and often and often associated with brain ischemia. This complication is difficult to detect, because clinical examination is hardly helpful in sedated patients and the performances of transcranial doppler can only detect the spasm of middle cerebral arteries.

Tissue Oxygen Pressure (PtiO2) Monitoring allows early detection of brain oxygenation local modifications and of brain ischemia, via continuous monitoring.

This study aims to assess the performance of the tissue oxygen pressure monitoring in detecting a vasospasm post aneurysmal subarachnoid hemorrhage.

Inclusion Criteria:

• severe aneurysmal subarachnoid hemorrhage
• patient sedated
• patient hospitalized in intensive care unit between January 2013 and August 2015
• multimodal neurologic monitoring including Tissue Oxygen Pressure and transcranial doppler

Exclusion Criteria:

• insonation impossible

Adult patients, hospitalized in intensive care unit and sedated, with severe aneurysmal subarachnoid hemorrhage