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