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Published on: January 17, 2013
Continuous electroencephalography predicts delayed cerebral ischemia after subarachnoid hemorrhage: A prospective
Eric S Rosenthal1,2, Siddharth Biswal1,2, Sahar F Zafar1,2
1Division of Neurocritical Care and Emergency Neurology, Massachusetts General Hospital, Boston, MA.
Insights
Continuous electroencephalography (cEEG) accurately predicts delayed cerebral ischemia (DCI) in subarachnoid hemorrhage (SAH) patients. This neurocritical care tool can help identify high-risk individuals for targeted interventions and clinical trials.
Area of Science:
- Neuroscience
- Critical Care Medicine
- Neurology
Background:
- Delayed cerebral ischemia (DCI) is a significant complication following subarachnoid hemorrhage (SAH).
- Current neurocritical care strategies aim to prevent DCI, but interventions carry risks and require careful patient selection.
- Retrospective studies suggest continuous electroencephalography (cEEG) measures may predict DCI, but rigorous prospective validation is lacking.
Purpose of the Study:
- To prospectively assess the accuracy of cEEG in predicting DCI after SAH.
- To establish the diagnostic performance of specific cEEG measures for DCI risk stratification.
- To provide evidence for using cEEG to guide interventions and clinical trial enrollment in SAH patients.
Main Methods:
- Prospective cohort study involving high-grade, nontraumatic SAH patients.
- Index test: prospective reporting of prespecified cEEG alarms (e.g., decreasing alpha variability, alpha-delta ratio, focal slowing, epileptiform abnormalities).
- Reference standard: DCI confirmed by blinded, adjudicated review; analysis using multistate survival and adjusted for baseline risk.
Main Results:
- cEEG monitoring was performed in 103 eligible SAH patients (mean duration 7.7 days).
- EEG alarms were detected in 96.2% of patients who subsequently developed DCI versus 19.6% of those who did not.
- Prespecified EEG findings demonstrated high sensitivity and specificity for DCI prediction across low and high baseline risk groups.
Conclusions:
- Prospective cEEG monitoring accurately predicts DCI in SAH patients.
- Specific cEEG findings, particularly late-onset epileptiform abnormalities, show strong predictive value.
- cEEG can potentially optimize the targeting of therapies to SAH patients at highest risk for secondary brain injury.
Objective:
Delayed cerebral ischemia (DCI) is a common, disabling complication of subarachnoid hemorrhage (SAH). Preventing DCI is a key focus of neurocritical care, but interventions carry risk and cannot be applied indiscriminately. Although retrospective studies have identified continuous electroencephalographic (cEEG) measures associated with DCI, no study has characterized the accuracy of cEEG with sufficient rigor to justify using it to triage patients to interventions or clinical trials. We therefore prospectively assessed the accuracy of cEEG for predicting DCI, following the Standards for Reporting Diagnostic Accuracy Studies.
Methods:
We prospectively performed cEEG in nontraumatic, high-grade SAH patients at a single institution. The index test consisted of clinical neurophysiologists prospectively reporting prespecified EEG alarms: (1) decreasing relative alpha variability, (2) decreasing alpha-delta ratio, (3) worsening focal slowing, or (4) late appearing epileptiform abnormalities. The diagnostic reference standard was DCI determined by blinded, adjudicated review. Primary outcome measures were sensitivity and specificity of cEEG for subsequent DCI, determined by multistate survival analysis, adjusted for baseline risk.
Results:
One hundred three of 227 consecutive patients were eligible and underwent cEEG monitoring (7.7-day mean duration). EEG alarms occurred in 96.2% of patients with and 19.6% without subsequent DCI (1.9-day median latency, interquartile range = 0.9-4.1). Among alarm subtypes, late onset epileptiform abnormalities had the highest predictive value. Prespecified EEG findings predicted DCI among patients with low (91% sensitivity, 83% specificity) and high (95% sensitivity, 77% specificity) baseline risk.
Interpretation:
cEEG accurately predicts DCI following SAH and may help target therapies to patients at highest risk of secondary brain injury. Ann Neurol 2018;83:958-969.
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