Brain Hypoxia Is Associated With Neuroglial Injury in Humans Post–Cardiac Arrest
Bibliographic record
Abstract
Rationale: Secondary brain hypoxia portends significant mortality in ischemic brain diseases; yet, our understanding of hypoxic ischemic brain injury (HIBI) pathophysiology in humans remains rudimentary. Objective: To quantify the impact of secondary brain hypoxia on injury to the neurovascular unit in patients with HIBI. Methods and Results: We conducted a prospective interventional study of invasive neuromonitoring in 18 post–cardiac arrest patients with HIBI. The partial pressures of brain tissue O 2 (PbtO 2 ) and intracranial pressure were directly measured via intraparenchymal microcatheters. To isolate the cerebrovascular bed, we conducted paired sampling of arterial and jugular venous bulb blood and calculated the transcerebral release of biomarkers of neurovascular injury and inflammation in the patients with HIBI and 14 healthy volunteers for control comparisons. Ten patients with HIBI exhibited secondary brain hypoxia (PbtO 2 <20 mmHg), while 8 exhibited brain normoxia (PbtO 2 ≥20 mmHg). In the patients with secondary brain hypoxia, we observed active cerebral release of glial fibrillary acidic protein (−161 [−3695 to −75] pg/mL; P =0.0078), neurofilament light chain (−231 [−370 to −11] pg/mL; P =0.010), total tau (−32 [−310 to −3] pg/mL; P =0.0039), neuron-specific enolase (−14 890 [−148 813 to −3311] pg/mL; P =0.0039), and ubiquitin carboxy-terminal hydrolase L1 (−14.7 [−37.7 to −4.1] pg/mL; P =0.0059) indicating de novo neuroglial injury. This injury was unrelated to the systemic global ischemic burden or cerebral endothelial injury but rather was associated with cerebral release of IL-6 (interleukin-6; −10.3 [−43.0 to −4.2] pg/mL; P =0.0039). No cerebral release of the aforementioned biomarkers was observed in patients with HIBI with brain normoxia or the healthy volunteers. Hyperosmolar therapy in the patients with secondary brain hypoxia reduced the partial pressure of jugular venous O 2 -to-PbtO 2 gradient (39.6 [34.1–51.1] versus 32.0 [24.5–39.2] mm Hg; P =0.0078) and increased PbtO 2 (17.0 [9.1–19.7] versus 20.2 [11.9–22.7] mm Hg; P =0.039) suggesting improved cerebrovascular-to-parenchymal O 2 transport. Conclusions: Secondary brain hypoxia is associated with de novo neuroglial injury and cerebral release of IL-6. Mitigating cerebrovascular-to-parenchymal limitations to O 2 transport is a promising therapeutic strategy for patients with HIBI with secondary brain hypoxia. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03609333.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".