Multimodality Neuromonitoring in Critically Ill Patients Without Primary Acute Brain Injury

The field of neuromonitoring has grown rapidly over the past 30 years, which has helped improve pathophysiological understanding, clinical care and outcomes for patients with primary ABI, including traumatic brain injury (TBI), subarachnoid haemorrhage (SAH), hypoxic-ischaemic injury and ischaemic or haemorrhagic stroke. The main goals of neuromonitoring are to better understand a patient’s cerebral physiology, provide early detection of neurological worsening or cerebral dysfunction to avoid progression to irreversible neurological injury, and assist with neuroprognostication. This is accomplished through a combination of serial neurological examinations, neuroimaging studies, and continuously monitoring different neurophysiological parameters. Numerous expert opinion and evidence-based reviews on the role of multimodality neuromonitoring in ABI have been published, including a consensus statement on multimodality monitoring in neurocritical care from the Neurocritical Care Society and the European Society of Intensive Care Medicine (Stocchetti et al. 2013; Le Roux et al. 2014). Most research and clinical practice in neuromonitoring has focused on patients with primary ABI, particularly TBI and SAH, and occurred in specialised neurocritical or neurotrauma care units (NCCUs). There is also a large population of critically ill patients without primary neurologic disease or ABI, who are at high risk for cerebral injury from their underlying disease process, systemic complications, or medical therapies, e.g. cardiac arrest, severe sepsis from extracranial sources, endocrinopathies such as diabetic ketoacidosis and hyper-/ hypo-thyroidism, renal and hepatic failure, rheumatologic conditions like haemophagocytic lymphohistiocytosis, and haematological abnormalities, including leukaemias and other neoplasms. The