HHE Emergency care supplement 2018 - Page 10

• 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