Effect of Circadian Biology on Subarachnoid Hemorrhage Onset, Intervention, and Outcome in ICU: A Narrative Review
Bibliographic record
Abstract
Abstract Rationale: Subarachnoid hemorrhages (SAH) are a life-threatening accumulation of blood between the arachnoid and pia mater. The incidence of SAH in the United States is between 10 and 14 out of 100,000 individuals per year, carrying a high risk of death and disability. Impaired sleep and circadian disruption lead to increased mortality and long-term morbidity in patients admitted to an intensive care unit (ICU). We performed a scoping review to explore the impact of circadian rhythms on SAH outcomes including rupture time, intervention time, incidence of delayed cerebral ischemia, circadian biology specific variables (i.e., melatonin levels, patient-reported sleep quality, temperature), and circadian entrainment. We aimed to identify gaps and whether there is a relationship between circadian rhythm and timing of management of a ruptured aneurysm, circadian biology, and patient-centered short- (e.g., delirium) and long-term (e.g., Glasgow outcome score) outcomes. Methods: A comprehensive search across multiple databases was completed on 26 July 2024 with the aid of a medical librarian. The search strategy focused on identifying English-language literature related to circadian rhythm interventions in critical care patients admitted with the primary diagnosis of SAH. Study selection and data extraction were independently verified. Results: Of the 881 unique articles identified, 25 studies met inclusion criteria. Sixteen articles explored diurnal patterns of the timing of aneurysm rupture. Of the included studies, the following circadian specific variables were studied: cortisol concentration (n=4), temperature (n=1), melatonin concentration (n=2), and gene expression (n=1). The effect of intervention timing (day vs night) on patient outcomes was studied in 2 articles. There was a consistent diurnal pattern of aneurysm rupture characterized by a morning peak, secondary evening peak, and nighttime trough, regardless of risk factors and sub-group analysis. Preliminary results demonstrate abnormal diurnal cortisol concentration profiles in SAH patients, correlated with continuous sedation and need for mechanical ventilation. Few studies evaluated the association between circadian specific variables, timing of SAH treatment (i.e., coiling or clipping of the aneurysm), and patient outcomes. Of the two that did, findings were mixed. Conclusion: Important gaps in the existing literature on the role of circadian biology in patients admitted to an ICU with SAH were identified. Despite finding a diurnal pattern of aneurysm rupture, further research is needed to understand the influence of circadian biology on management (e.g., timing of coiling) and related complications (e.g., delayed cerebral ischemia).
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.028 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 0.004 |
| Bibliometrics | 0.007 | 0.010 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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 source (direct Gemma or distilled Codex), 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".