Study measurements of the diameter and Doppler flow velocity of the superior mesenteric artery (SMA) using abdominal ultrasound in order to evaluate the potential additional risk of non-occlusive mesenteric ischemia (NOMI) and non occlusive bowel necrosis (NOBN) in patients undergoing hypertensive therapy for cerebral vasospasm in Aneurysmal Subarachnoid Hemorrhage (aSAH), to justify the withholding of enteral nutrition.