Safety, Feasibility, and Efficacy of Non-invasive Vagus Nerve Stimulation (nVNS) in the Treatment of Aneurysmal Subarachnoid Hemorrhage

Inclusion Criteria: * Male or female, 18-85 years of age * Ruptured aneurysmal SAH confirmed by angiography and repaired by neurosurgical clipping or endovascular occlusion (coiling) * Modified Glasgow Coma Scale (mGCS) score ≥ 10 and Hunt Hess 1-4 within 72 hours of presumed aneurysm rupture * Enrollment and initiation of nVNS treatment must occur within 72 hours of presumed aneurysm rupture * Provide a legally obtained informed consent form from the participant or the legally authorized representative (LAR); telephonic consent is acceptable * Female participants of reproductive age must have a negative pregnancy test result (urine or blood) Exclusion Criteria: * Use of any concomitant electrostimulation device, including a pacemaker, defibrillator, or deep brain stimulator * No plan to secure aneurysm, defined as aneurysm that has not been surgically or endovascularly treated * Previous neck dissection or radiation * History of carotid artery disease or carotid surgery/dissection * History of secondary or tertiary heart blocks, ventricular tachycardia, or supraventricular tachycardia (SVT; including atrial fibrillation) * Screws, metals, or devices in the neck * Currently participating in an investigational drug or device clinical trial with potential to confound data collection