Early Redox Biomarker Changes After Stellate Ganglion Block in Traumatic Brain Injury

Oxidative stress is a key mediator of secondary brain injury after traumatic brain injury (TBI). The stellate ganglion block (SGB) has been shown to modulate cerebral hemodynamics and neuroinflammation in brain-injured patients, but its effect on circulating redox biomarkers in human TBI has not been studied. This is a post hoc secondary analysis of stored paired arterial and internal jugular venous blood samples from a prospective, single-center, before-and-after pilot study conducted at the University Medical Centre Ljubljana (parent trial: NCT04208477). Twenty adult patients with moderate-to-severe TBI (Glasgow Coma Scale score 12 or lower before intubation) who received a single ultrasound-guided SGB were included. Paired blood samples collected at baseline and at 12 and 24 hours after SGB were assayed for derivatives of reactive oxygen metabolites (d-ROMs), plasma antioxidant capacity (PAT), the composite oxidative stress index (OSI = d-ROMs/PAT), the early lipid-peroxidation marker hexanoyl-lysine (HEL), and the oxidative DNA-damage marker 8-hydroxy-2'-deoxyguanosine (8-OHdG). No new intervention was administered, no additional patients were enrolled, and no additional biological samples were collected. The primary outcome is the within-participant change in jugular venous OSI from baseline to 12 hours after SGB. Secondary outcomes include temporal changes in d-ROMs, HEL, and 8-OHdG in both arterial and jugular venous compartments, and the interaction between blood compartment and time. The statistical analysis plan for the oxidative-stress endpoints was documented before the biomarker assays were performed. This pilot study provides variability estimates and preliminary data to inform the design of future controlled trials evaluating SGB as a potential modulator of post-traumatic oxidative stress.