Sedation with dexmedetomidine rather than
benzodiazepines appears to reduce the incidence
of delirium in the ICU. In a multicenter, randomized
trial predominantly involving medical
patients in the ICU, the administration of dexmedetomidine
or midazolam resulted in similar
proportions of time within the target range of
−2 to +1 on the Richmond Agitation–Sedation
Scale among patients, but those assigned to receive
dexmedetomidine had a reduced risk of
delirium and spent less time undergoing mechanical
ventilation.21 As compared with a lorazepam
infusion, sedation with dexmedetomidine resulted in more time at the target level of sedation
and longer survival without delirium or
coma.20 In a multicenter European trial, patients
were randomly assigned to continue treatment
with their current sedative (midazolam or propofol)
or to switch to sedation with up to 1.4 μg
of dexmedetomidine per kilogram of body weight
per hour.19 There were no between-group differences
in the proportion of time at the target level of sedation. The rates of the composite end
point of agitation, anxiety, or delirium were
lower with dexmedetomidine than with propofol,
but the rates with dexmedetomidine were
equivalent to those with midazolam. When delirium
was assessed with the use of the CAMICU
48 hours after sedation was discontinued,
there were no significant differences among the
groups.