Patients hospitalized in the intensive care unit (ICU) and developing clinical manifestations of cerebral vasospasm will undergo a computerized tomography (CT) angiography and a CT perfusion scan. If the vasospasm will be confirmed by the CT imaging, a cervical sympathetic nerve block under ultrasound guidance will be performed.~The block consists in the deposition of local anesthetic at the cervical sympathetic ganglion that will be visualized with an ultrasound device. A periganglionar catheter will be left in place. A CT angiography and CT perfusion will be repeated to check the effect of the block on the brain vasculature after the block is done.~Patients will have a daily monitoring of their neurological function and of their cerebral blood flow with transcranial doppler in the ICU.
The purposes of this study are twofold: 1) to assess the effect of a cervical sympathetic block on cerebral blood flow in patients suffering from cerebral vasospasm, after aneurysmal subarachnoid hemorrhage; 2) to evaluate the effect of the sympathetic block on the recovery of the neurological function.