Studying How Stellate Ganglion Block Affects Retinal Blood Flow in Adults

What this Trial Is About

Researchers are investigating the effects of the stellate ganglion nerve block on retinal microcirculation in patients with neurological critical illnesses such as intracranial hemorrhage and subarachnoid hemorrhage. These conditions often cause surges in the sympathetic nervous system that may lead to secondary brain injury through mechanisms like diffuse vasospasm and cerebral ischemia. The study aims to understand how blocking the sympathetic nervous system might influence microcirculation in the eye. Participants in this observational study will receive the stellate ganglion nerve block as part of their standard medical care. The key procedure involves imaging the retinal microcirculation using Optical Coherence Tomography Angiography OCTA before and after the nerve block. This technique is known to reduce cerebral sympathetic activity and vasospasm, and the study will assess its impact on retinal blood vessel density and perfusion. During the study, participants will undergo OCTA scans to measure vascular and perfusion density one day after the procedure. Researchers will monitor these changes to evaluate the nerve blocks effect on retinal microcirculation. The study is sponsored by the University of Texas Southwestern Medical Center and will include adult patients receiving this nerve block for approved conditions. Participation involves imaging and standard care without additional interventions, and the study is expected to conclude by October 2026.

Effect of the Stellate Ganglion Block on the Retinal Microcirculation