emergency and critical care
Sedation in
neurocritical care
Sedation is an essential therapeutic strategy in the care
of neurocritical patients. Potential benefits and risks of limiting
deep sedation and daily interruption of sedation remain unclear
Berta Monleón MD
Cristina Álvarez MD
Rafael Badenes MD PhD
Department
Anesthesiology and
Surgical-Trauma Intensive
Care, Hospital Clinic
Universitari de València,
Spain. University of
Valencia
Sedation is one of the main facilities in the
intensive care unit (ICU). However, it is well
known that no sedation, or minimising it, results
in better outcomes, such as decreased length of
hospital stay, shorter duration of mechanical
ventilation, reduced healthcare costs and
a reduced need for additional examinations to
determine brain function. It is also related to
early mobilisation of the patient, but it is unclear
if it decreases delirium. Most of the review studies
supporting this evidence are based on populations
with non-acute brain injury. Traditionally, these
patients were kept under sedation in the early
phase to prevent the secondary insult. 1,2
Sedation in the ICU has different roles. The
drugs used are intravenous, such as propofol and
midazolam. 2 The objective is to control pain and
anxiety, reduce agitation and achieve patient–
ventilator synchrony. Nonetheless, there are
situations where sedation has specific roles such
as in patients with high intracranial pressure
(ICP), those requiring muscular relaxation for any
reason, and those with a status epilepticus. 2
The trend now is to interrupt sedation as soon
as possible and avoid it during the day. However,
these two new settings have to be analysed and
compared with the benefit they may have
concerning the risk of exacerbating intracranial
hypertension in patients with reduced brain
compliance. 1
The ideal sedative drug should be able to
decrease ICP and maintain an appropriate
cerebral perfusion without interfering with its
autoregulation. Additionally, it should decrease
the cerebral metabolic rate of oxygen and have
neuroprotective and anticonvulsant properties.
In regard to its pharmacological properties, it
should have a predictable response, rapid onset
and wake-up, and minimum secondary effects. 2
There are no management of sedation
guidelines in neurocritical patients. Each ICU
bases its decisions on its own experiences and
follows basic recommendations that are well
accepted in the scientific community; however,
we need to establish algorithms for the
management of sedation these patients.
Need for sedation
Sedation in neurocritical patients is essential
to relieve pain, anxiety, reduce ICP, decrease
oxygen consumption, tolerate therapeutic
manoeuvers, and improve adaptation to
mechanical ventilation. However, it has its
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drawbacks. It prevents frequent neurological
evaluation, thus decreasing prognostic capacity
because clinicians are incapable of detecting
changes in the brain state.
By contrast, sedation is part of management in
certain other conditions; targeted temperature
management, elevated ICP and refractory status
epilepticus. 1 It is a first-line treatment when ICP
is high, together with other measures. In most
cases, elevated ICP develops within 48 hours of
the brain insult; however, it can develop earlier
than this.
Prolonged deep sedation might possibly
worsen cognitive results after its cessation and
contribute to polyneuropathy in critical patients.
Unless deep sedation or general anaesthesia is
necessary, analgesia must precede sedation.
Nowadays, there is a new trend to base sedation
on opioids. 3
The guidelines for sedoanalgesia in massive
cerebral infarction establish the following
recommendations: 4
• Analgesia and sedation are recommended if
signs of pain, anxiety, or agitation arise (strong
recommendation, very low quality of evidence)
• The lowest possible sedation intensity and
earliest possible sedation cessation is
recommended, while avoiding physiological
instability and discomfort (strong
recommendation, very low quality of evidence)
• The routine use of daily wake-up trials is not
recommended. Caution is particularly warranted
in patients prone to ICP crisis. Neuromonitoring
of at least ICP and CPP is recommended to guide
sedation, and daily wake-up trials should be
abandoned or postponed at signs of physiological
compromise or discomfort.
Sedation assessment
Neurophysiological monitoring should be
considered a routine practice for neurocritical
patients requiring sedation. Over-sedation
increases the risk of infection, delays the
removal of mechanical ventilation, and
increases the length of stay in ICUs. On the
other hand, infrasedation causes agitation,
anxiety, and risk of accidents such as self-
extubation, pulling out of catheters, discomfort,
or ventilator asynchronies 5 and has prevented
neurologic deterioration. 6,7
A number of scales to evaluate arousal, deep
of sedation and response to stimuli are available: 8
• Ramsay Scale: evaluates consciousness