Dexmedetomidine produces more sleep-like brain activity compared with propofol in human participants.

BACKGROUND

Dexmedetomidine is a selective α2-adrenergic agonist used as an anaesthesia adjunct to produce a state of sleep-like sedation. How brain activity compares quantitatively during dexmedetomidine anaesthesia with that during natural sleep remains unclear. We have shown that the general anaesthetic propofol is associated with changes in connectivity and cortical network structure similar to sleep. Here, we compare quantitatively the effects of dexmedetomidine, propofol, and sleep on brain activity.

METHODS

Intracranial encephalography recordings were obtained in 34 patients with epilepsy being evaluated for seizure resection surgery. Band power, functional connectivity, and network entropy were measured during task-free periods just before surgery, during anaesthesia with either dexmedetomidine or propofol, and during overnight sleep. Anaesthesia stage (wake, sedated, unresponsive) was determined using the Observer's Assessment of Arousal/Sedation. Sleep was staged using standard polysomnography.

RESULTS

Significant differences in delta power were observed during dexmedetomidine and propofol anaesthesia and during sleep. However, the magnitude of changes in delta power was smaller and regionally heterogeneous for propofol compared with dexmedetomidine and sleep, whereas changes in network entropy were larger for propofol compared with dexmedetomidine and sleep. Quantitative comparisons between changes in delta power and network entropy suggest that unresponsiveness under dexmedetomidine anaesthesia produces a similar brain state to that observed during N2 sleep.

CONCLUSIONS

Although delta power, functional connectivity, and network entropy all showed changes during propofol, dexmedetomidine, and sleep, the magnitudes of these changes suggest that the effects of dexmedetomidine are more similar than those of propofol to sleep, specifically to N2 sleep.