Secondary brain injury in trauma patients: the effects of remote ischemic conditioning.

BACKGROUND Management of traumatic brain injury (TBI) is focused on preventing secondary brain injury. Remote ischemic conditioning (RIC) is an established treatment modality that has been shown to improve patient outcomes secondary to inflammatory insults. The aim of our study was to assess whether RIC in trauma patients with severe TBI could reduce secondary brain injury. METHODS This prospective consented interventional trial included all TBI patients admitted to our Level 1 trauma center with an intracranial hemorrhage and a Glasgow Coma Scale (GCS) score of 8 or lower on admission. In each patient, four cycles of RIC were performed within 1 hour of admission. Each cycle consisted of 5 minutes of controlled upper limb (arm) ischemia followed by 5 minutes of reperfusion using a blood pressure cuff. Serum biomarkers of acute brain injury, S-100B, and neuron-specific enolase (NSE) were measured at 0, 6, and 24 hours. Outcome measure was reduction in the level of serum biomarkers after RIC. RESULTS A total of 40 patients (RIC, 20; control, 20) were enrolled. The mean (SD) age was 46.15 (18.64) years, the median GCS score was 8 (interquartile range, 3-8), and the median head Abbreviated Injury Scale (AIS) score was 3 (interquartile range, 3-5), and there was no difference between the RIC and control groups in any of the baseline demographics or injury characteristics including the type and size of intracranial bleed or skull fracture patterns. There was no difference in the 0-hour S-100B (p = 0.9) and NSE (p = 0.72) level between the RIC and the control group. There was a significant reduction in the mean levels of S-100B (p = 0.01) and NSE (p = 0.04) at 6 hours and 24 hours in comparison with the 0-hour level in the RIC group. CONCLUSION This study showed that RIC significantly decreased the standard biomarkers of acute brain injury in patients with severe TBI. Our study highlights the novel therapeutic role of RIC for preventing secondary brain insults in TBI patients. LEVEL OF EVIDENCE Therapeutic study, level III.