Asymmetry of Bispectral Index (BIS) in severe brain-injured patients treated by barbiturates with unilateral or diffuse brain injury

The Role of Processed Electroencephalography in the Detection and Management of Acute Cerebral Ischemia: A Scoping Review

Processed electroencephalography (pEEG) is increasingly used to titrate the depth of anesthesia. Whether such intra-procedural pEEG monitoring can offer additional information on cerebral perfusion or acute focal or global cerebral ischemia is unknown. This scoping review aimed to provide a narrative analysis of the current literature reporting the potential role of pEEG in adults with acute cerebral ischemia. In keeping with the scoping review methodology, a broad search strategy was defined, including descriptions of encephalography in acute ischemic stroke, carotid endarterectomy, cardiac surgery, and cardiac arrest. Additional screening of citations was conducted by 2 independent assessors. From 310 records, 28 full-text articles met inclusion criteria. Most identified studies were observational in design, and described the diagnostic ability of pEEG to identify cerebral hypoperfusion or its prognostic sensitivity after stroke or carotid surgery. No studies were identified that evaluated pEEG in the specific setting of endovascular therapy for acute ischemic stroke. Low sensitivity associations between pEEG indices and cerebral blood flow were highlighted, which may be influenced by cerebral autoregulatory thresholds. Despite the associations reported in observational studies, this review identified significant uncertainty in the role of pEEG during cerebral ischemia. There is a paucity of high-level observational (cohort or case-control) or randomized trial research examining the possible role of pEEG for the detection and management of cerebral ischemia during acute stroke, including during endovascular therapy, or in other common scenarios of acute cerebral ischemia.

Noninvasive Neuromonitoring: Current Utility in Subarachnoid Hemorrhage, Traumatic Brain Injury, and Stroke

Noninvasive neuromonitoring is increasingly being used to monitor the course of primary brain injury and limit secondary brain damage of patients in the neurocritical care unit. Proposed advantages over invasive neuromonitoring methods include a lower risk of infection and bleeding, no need for surgical installation, mobility and portability of some devices, and safety. The question, however, is whether noninvasive neuromonitoring is practical and trustworthy enough already. We searched the recent literature and reviewed English-language studies on noninvasive neuromonitoring in subarachnoid hemorrhage, traumatic brain injury, and ischemic and hemorrhagic stroke between the years 2010 and 2015. We found 88 studies that were eligible for review including the methods transcranial ultrasound, electroencephalography, evoked potentials, near-infrared spectroscopy, bispectral index, and pupillometry. Noninvasive neuromonitoring cannot yet completely replace invasive methods in most situations, but has great potential being complementarily integrated into multimodality monitoring, for guiding management, and for limiting the use of invasive devices and in-hospital transports for imaging.