Electroencephalogram signatures of propanidid-mediated sedation and unconsciousness.

Propanidid is an intravenous short-acting sedative-hypnotic anesthetic in the eugenol family that acts as a positive allosteric modulator of the gamma-aminobutyric acid type A (GABAA) receptor. However, its neural circuit mechanisms have not been characterized. We compared the EEG signatures of patients anesthetized with propanidid to those anesthetized with propofol. We characterized the EEG recordings of 13 propanidid- and 13 propofol-mediated general anesthesia cases using spectral and coherence analyses. During propanidid-mediated unconsciousness, we observed a significant increase in the 0-18.5 Hz power and a decrease in the 30.5-40 Hz power compared with the baseline. Compared to the propofol cohort, the suppression in the 23-40 Hz band power was significantly less in the propanidid cohort during unconsciousness. The coherence in the 0-40 Hz range was not significantly different between the two cohorts. The propanidid cohort showed a shorter average offset time (4.8 min) than the propofol cohort (5.9 min), which was not significant. This preliminary investigation showed that the EEG signatures of propanidid-mediated unconsciousness are similar to those of propofol, suggesting a similar GABAergic mechanism of network action. Our work provides a basis to characterize the neural mechanisms of propanidid-mediated sedation and unconsciousness.NEW & NOTEWORTHY Propanidid is a short-acting intravenous anesthetic of the eugenol group that has been safely used in Mexico for over 20 years. Like propofol, it acts via GABAergic mechanisms; however, its effects on neural circuits remain uncharacterized. Therefore, we compared EEG signatures between patients anesthetized with propanidid and propofol. Our work suggests similar neural mechanisms for propanidid and propofol. As with propofol, propanidid's EEG signatures could be used to monitor sedation and unconsciousness.