Sedation is one of the main facilities in the intensive care unit (ICU). However, it is well known that no sedation, or minimizing it, results in better outcomes, such as decreased length of hospital stay, shorter duration of mechanical ventilation, reduced health care costs and a reduced need for additional examinations to determine brain function.
It is also related to early mobilization 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.
Role Of Sedation
Sedation in the ICU has different roles. The drugs used are intravenous, such as propofol and midazolam. 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.
Sedation Reduces Brain Complications
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 analyzed and compared with the benefit they may have concerning the risk of exacerbating intracranial hypertension in patients with reduced brain compliance.
The ideal sedative drug should be able to decrease ICP and maintain an appropriate cerebral perfusion without interfering with its autoregulation.
Need for sedation
Sedation in neurocritical patients is essential to relieve pain, anxiety, reduce ICP, decrease oxygen consumption, tolerate therapeutic maneuvers, and improve adaptation to mechanical ventilation. However, it has its drawbacks.
Prolonged deep sedation might worsen cognitive results after its cessation and contribute to polyneuropathy in critical patients. Unless deep sedation or general anesthesia is necessary, analgesia must precede sedation. Nowadays, there is a new trend to base sedation on opioids.
The guidelines for sedoanalgesia in massive cerebral infarction establish the following recommendations:
- 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.
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.
Acute Brain Injury
A study showed that BIS values significantly correlated with RASS and SAS scores in patients with acute brain injury. In another study, the BIS reliably assessed sedation levels during continuous propofol infusion in the same type of patients.
Sedation and analgesia are frequently used in the management of critically ill patients and is related to a longer hospital stay and more difficult weaning from mechanical ventilation. However, in neurointensive care units, it is also a therapeutic strategy. Therefore studies have been developed to achieve efficient sedation and to avoid the adverse effects as much as possible.
First-Line Of Sedatives
Midazolam and propofol are the most frequently used first-line sedatives; however, use of benzodiazepines is less common because of their deleterious effects, such as prolonging mechanical ventilation time and increasing awakening times.
New trends, such as inhalation sedation or ketamine, are beginning to garner more attention, but more studies are required to fully confirm their use.