Pharmacodynamics of a stimulus-free behavioural paradigm to track conscious states during sedation with dexmedetomidine

Sedatives are powerful tools to study consciousness, allowing investigators to manipulate brain states and associated neurophysiological markers. Conscious states are typically inferred through responses to external stimuli such as auditory tasks and noxious stimulation. The use of an auditory task to probe loss of responsiveness (LOR) during dexmedetomidine sedation previously yielded a mean (standard deviation [sd]) effect-site concentration (Ce) of 2.06 (0.66) ng ml–1 at LOR.1 Here, we report a stimulus-free behavioural paradigm to assess conscious states during titration of dexmedetomidine.