EEG dynamics under anesthetics-induced loss and return of responsiveness with A constant rate infusion.

OBJECTIVE

This study aims to characterize the electroencephalographic dynamics during the transition to and from loss of responsiveness (LOR) induced by three anesthetics.

METHODS

High-density EEG was recorded in 60 patients randomly receiving propofol, dexmedetomidine, or ketamine with a constant rate infusion. Spectral power, phase-amplitude coupling (PAC), coherence and directed phase transfer entropy during awake, LOR and recovery (ROR) states were analyzed to evaluate neural dynamics associated with altered conscious states.

RESULTS

Propofol increased global alpha power and low-frequency slow oscillations (SO) without "alpha anteriorization" during LOR. Dexmedetomidine increased SO but decreased alpha power. Ketamine reduced alpha power and increased occipital theta and gamma power. Further, three anesthetic displayed distinct PAC patterns and induced region-specific and frequency-specific long-range functional connectivity patterns. Directed connectivity analysis indicated propofol and ketamine rather than dexmedetomidine inhibited feedback connectivity during LOR.

CONCLUSIONS

Three anesthetics induced differential spectral power, PAC, and network connectivity during the transition to and from LOR when infused with a constant rate, suggesting that EEG dynamics vary not only among anesthetics, but also among regimens of their administration.

SIGNIFICANCE: Anesthetic-specific neural signatures and administration-dependent EEG patterns, advance precision anesthesia monitoring and deepen understanding of conscious state transitions under distinct pharmacologic modulations.