Alpha-delta ratio as a robust marker of the impact of cerebral blood flow on EEG signal during general anesthesia
Authors' conclusion
The ADR appears to be a delayed marker for studying the relationship between CBF and intraoperative EEG. We observed asymmetry in the cerebral pressure-flow relationship during increasing and decreasing mAP challenges.
Study context
- Population
- Patients under stabilized general anesthesia (GA) in neuroradiology procedures with EEG, mAP and cerebral blood flow (CBF) (transcranial Doppler MCAvmean) monitored
- Participants
- 63 participants
- Outcome
- Association between MCAvmean changes caused by an mAP challenge and intraoperative EEG parameters (ADR)
Main finding
As reported in the abstract
MCAvmean changes vs ADR
- Significant linear relationship between MCAvmean changes and alpha-delta ratio (ADR)
- Strongest association for a time delay between 4' and 9'30 s (permutation test)
Secondary outcomes
| Outcome | Positive mAP challenges | Negative mAP challenges | P value |
|---|---|---|---|
| Pressure-flow relationship (linear regression coefficients): positive vs negative mAP challengesAsymmetric responses | 0.28 (range 0.12–0.37) | 0.38 (range 0.25–0.74) | P = 0.004 |
Duration of mAP challenges
- Median duration 410 [220-585] seconds
Original publication
Alpha-delta ratio as a robust marker of the impact of cerebral blood flow on EEG signal during general anesthesia. Anaesth Crit Care Pain Med. Published 30 September 2025. doi:10.
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