Behavioral state, subjective reports, and ensuing classification of the state of consciousness
The subjects were prone to fluctuation in responsiveness because of the administered ECResponsiveness state categorization and cumulative tracer uptake weightsThe final number (proportions) of subjects assigned to responsiveness state categories and median (IQR) uptake weights for respective categories in each treatment group. The overall proportions of responsive, unresponsive, and unclassified subjects were significantly different between treatment groups (χResponsiveness during the experiment. Responsiveness weights based on tracer kinetic modeling and summary of responsiveness during the experiment. After drug administration, 11 (out of 15), 18 (out of 20), and 11 (out of 30) unresponsive subjects from the propofol, dexmedetomidine and sevoflurane groups, respectively, were successfully interviewed for mental content during the preceding unresponsive period. Disconnected experiences, i.e., experiences taking place during unresponsiveness but not directly associated with external perceptual content, such as dreams, were reported by 4/11 (36%), 15/18 (83%), and 5/11 (45%) of subjects in the propofol, dexmedetomidine and sevoflurane groups, respectively. None of the unresponsive subjects in the S-ketamine group could be interviewed immediately after terminating the drug infusion because of residual drug-effects. There were no reports indicating connectedness. Thus, all unresponsive subjects were classified as disconnected, whereas all responsive subjects were classified as connected and conscious.