• Richmond Agitation Sedation Scale (RASS):
examines cognition
• Sedation Agitation Scale (SAS) and Motor
Activity Assessment Scale (MAAS): monitor
sedation and arousal.
Their use can reduce the amount of sedatives
given to achieve a specific sedation target,
decreasing the number of days on mechanical
ventilation and cost of hospital stay; however,
no validation is available in the neuro-ICU
environment. 2 The Nociception Coma Scale has
emerged as a valid tool to assess pain in patients
with disorders of consciousness. 9
When it is not possible to use these scales,
for example, in patients who require muscular
relaxation, then an electrophysiological endpoint
must be used instead. One example is bispectral
index (BIS) monitoring, 10 which has made
adjustments of sedation possible. A study showed
that BIS values significantly correlated with RASS
and SAS scores in patients with acute brain
injury. 11 In another study, the BIS reliably assessed
sedation levels during continuous propofol
infusion in the same type of patients. 12
BIS was initially developed for monitoring the
depth of general anaesthesia in patients without
brain pathology. It is thought that the ABI (acute
brain injury) may influence the BIS algorithm
because of EEG changes related to the pathology
itself rather than to the sedative state. 1
The approach to sedation should first consider
the severity of acute brain injury and the cerebral
physiological state, mainly ICP. Figure 1 shows
a possible algorithm for the management of
sedation in neurointensive care units. 1
The first things to consider are appropriate
control of pain, control of agitation and
promoting ventilator synchrony. In patients with
intracranial hypertension, the targets for sedation
and analgesia should be titrated to control ICP
and brain tissue oxygen pressure. 1
Need to wake up
For the clinical assessment of neurocritical
patients, interruption of continuous sedation (IS)
is therefore necessary. This is usually short-term,
aimed at evaluating the patients and planning
further management strategies, including the
definitive sedation interruption once the clinical
concern and IS does not provoke patients’ distress
and metabolic imbalance. 2 Withdrawal of
sedation and IS by daily wake-up tests might
appear beneficial to these patients by allowing
clinical neuro-monitoring and timely detection of
warning neurological signs. 13 Daily IS trials have
the potential to reduce mechanical ventilation
duration and the need for tracheostomy. 14 These
potential benefits, however, must be balanced
against the risk of further cerebral
haemodynamic deterioration when sedation is
stopped abruptly. 15 Cerebral hypoperfusion and
raised ICP might result in an imbalance of energy
supply and demand, especially for the injured
brain and, therefore, aggrava