In others, there may be some direct transluminal pressure effect that leads to arterial dilation.227 Traditionally, hemodynamic augmentation has consisted of he- modilution (a common occurrence in this population), hypervol- emia, and hypertensive therapy. Accumulating literature has shifted the focus from this triple-H therapy to the maintenance of euvolemia and induced hypertension.228 One novel method of hemodynamic augmentation under investigation is an aortic balloon device, approved under a humanitarian device exemption.229 Endovascular intervention is often used in patients who do not improve with hemody- namic augmentation and those with sudden focal neurological deficits and focal lesions on angiography referable to their symptoms.230 Interventions generally consist of balloon an- gioplasty for accessible lesions and vasodilator infusion for more distal vessels. Many different vasodilators are in use. In general, these are calcium channel blockers, but nitric oxide donors have been used in small series as well.231 Papaverine is used less frequently because it can produce neurotoxic- ity.232 The primary limitation of vasodilator therapy is the short duration of benefit. As with hemodynamic augmenta- tion, there have been no randomized trials of these interven- tions, but large case series have demonstrated angiographic and clinical improvement.233 Management of Cerebral Vasospasm and DCI After aSAH: Recommendations 1. Oral nimodipine should be administered to all patients with aSAH (Class I; Level of Evidence A). (It should be noted that this agent has been shown to improve neuro- logical outcomes but not cerebral vasospasm. The value of other calcium antagonists, whether administered orally or intravenously, remains uncertain.) 2. Maintenance of euvolemia and normal circulating blood volume is recommended to prevent DCI (Class I; Level of Evidence B). (Revised recommendation from previous guidelines) 3. Prophylactic hypervolemia or balloon angioplasty before the development of angiographic spasm is not recommended (Class III; Level of Evidence B). (New recommendation) 4. 