Auricular VNS Following Subarachnoid Hemorrhage

This study will evaluate whether non-invasive auricular vagal nerve stimulation lowers inflammatory markers, and improves outcomes following spontaneous subarachnoid hemorrhage.

Vagal nerve stimulation (VNS) has been studied in several inflammatory conditions, and has been implemented in animal models of subarachnoid hemorrhage (SAH) with promising results. The purpose of the proposed study is to determine how applying auricular VNS in patients presenting with spontaneous SAH impacts their expression of inflammatory markers in their blood and cerebrospinal fluid (CSF), and how it impacts their clinical course and outcomes. This study will involve randomizing patients to stimulation with VNS, or sham stimulation. Blood and CSF will be collected on admission, and serially throughout the patient's admission. Clinical events tracked during the hospital stay include development of cerebral vasospasm, need for CSF diversion via a shunt, stress-induced cardiomyopathy, and development of stroke or global cerebral ischemia. Outcomes following admission will include functional scores at discharge, and at follow-up visits for up to 2 years after discharge.

All participants will be fitted with an auricular stimulator, but blinded to whether they are receiving stimulation or not. Outcome scores will be assessed and recorded by clinicians blinded to treatment arm.

Participants will have an auricular vagal nerve stimulator applied twice daily, without the stimulation applied

IL-12, GM-CSF, IFN gamma, IL-1b, IL-10, IL-13, IL-17A, IL-2, IL-4, IL-5, IL-6, IL-8, TNF alpha from blood draws

IL-12, GM-CSF, IFN gamma, IL-1b, IL-10, IL-13, IL-17A, IL-2, IL-4, IL-5, IL-6, IL-8, TNF alpha from blood draws

IL-12, GM-CSF, IFN gamma, IL-1b, IL-10, IL-13, IL-17A, IL-2, IL-4, IL-5, IL-6, IL-8, TNF alpha from cerebrospinal fluid

IL-12, GM-CSF, IFN gamma, IL-1b, IL-10, IL-13, IL-17A, IL-2, IL-4, IL-5, IL-6, IL-8, TNF alpha from cerebrospinal fluid

Presence of vasospasm based on any of the following criteria: 1) Radiographic evidence of vasospasm on CT angiogram or catheter angiogram, 2) Need for blood pressure augmentation or hypervolemia, 3) Need for intraarterial or intrathecal vasodilator, 4) Need for angioplasty

Presence of hydrocephalus based on any of the following criteria: 1) Need for temporary CSF diversion via an external ventricular drain, 2) Need for permanent CSF diversion via a ventricular shunt

Presence of stressed-induced cardiomyopathy based on any of the following criteria: 1) New troponin elevation, 2) New EKG changes (specifically ST segment elevation, ST segment depression, left bundle branch block, prolonged QT interval), 3) New findings of cardiomyopathy on echocardiogram

Presence of cerebral ischemia based on the following criteria: Radiographic evidence of a new infarct or stroke

Modified Rankin Scale for Neurological Disability (minimum score 0, maximum score 6, better outcomes have lower scores)

Inclusion Criteria: Spontaneous subarachnoid hemorrhage Exclusion Criteria: Trauma-induced subarachnoid hemorrhage Ongoing chemotherapy Taking immunosuppressive medications for other medical illnesses Presence of a pacemaker Prolonged bradycardia at time of admission