Brain Injury Biomarkers in Humans Undergoing General Anaesthesia and Noncerebral Surgery

Journal article, 2025

Introduction: This study is aimed at investigating brain injury biomarkers neurofilament light (NfL), tau, neuron-specific enolase (NSE), calcium-binding protein S100B (S100B) and glial fibrillary acidic protein (GFAP) in blood during general anaesthesia and abdominal surgery in patients without cerebral injury, to evaluate the effect of general anaesthesia and surgery per se on the release of these biomarkers. Methods: This prospective observational study was conducted at Sahlgrenska University Hospital, Gothenburg, Sweden, between September and November 2021. Patients scheduled for mixed abdominal surgery under general anaesthesia were included. Vital parameters and near-infrared spectroscopy (NIRS) for cerebral perfusion were continuously monitored. Blood pressure was kept close to each patients’ preanaesthetic mean arterial pressure. Vasopressors and fluids were administered at the discretion of the attending physician, not influenced by the study. Results: There were 23 patients (11 females [48%] and 12 males [52%]) included in the study. NfL, tau, NSE and S100B increased significantly when 2- and 24-h concentrations were compared with preoperative values, whilst GFAP did not. The continuous mean arterial blood pressure was 83.5 mmHg, with a 62.2–90.4 mmHg range. The mean NIRS was 77.5% (range 62.2–90.4). No patient had a drop in NIRS of 12% or more. Postoperative symptoms of confusion or neurological deficits were not observed in any patient within 48 h from the start of anaesthesia. Conclusion: General anaesthesia and abdominal surgery in patients with well-maintained cerebral perfusion and no clinical signs of postoperative cerebral injury caused an increase in levels of brain injury biomarkers NfL, tau, NSE and S100B in blood. Interestingly, there was no increase in levels of GFAP in the blood. These data suggest that GFAP is the only biomarker, amongst the investigated biomarkers, which is not released into the bloodstream during general anaesthesia and surgery in patients with no suspected brain injury. More extensive studies on this subject are warranted. Trial Registration: ClinicalTrials.gov identifier: NCT03919370.