Effect of Dexmedetomidine Upon Sleep Postoperatively

Physiological similarities exist between the anesthetized state and sleep. Pathways within
the brain controlling sleep and wakefulness are also affected by anesthesia. One
significant difference between the states of anesthesia and sleep is the ability to respond
whenever a relatively mild stimulus is applied, e.g. verbal command or gently shaking.
Interestingly, this feature of arousability is seen when dexmedetomidine is used for
sedation but is absent when alternative intravenous anesthetic agents, e.g. propofol, are
used to provide similar degree of sedation. Recent studies have shown that dexmedetomidine
acts on receptors located within the locus ceruleus, which are responsible for both sleep
and anesthesia.

During a recent study volunteers received an infusion of dexmedetomidine during the
afternoon prior to remaining under study conditions for the duration of the night. The
study was not designed to measure sleep but anecdotal reporting from the participants
suggested that they were able to resume their normal day’s activities whilst the subject
receiving placebo felt extremely fatigued from lack of sleep. This prompted the
establishment of a pilot study to determine if dexmedetomidine could provide restorative
sleep to people under disturbed sleep conditions i.e. postoperative patients.