Multimodal neuromonitoring of a brain death with electrophysiological markers of cortical and subcortical loss of functions

Abstract

Abstract Brain death, characterized by the permanent cessation of all brain functions including the brainstem, is subject to varying diagnostic criteria internationally. In France, the confirmation of the clinical criteria requires ancillary tests such as CT angiogram or EEG. The timing of these tests presents challenges, especially in the intensive care setting. This study outlines a novel approach for the assessment of brainstem and cortical functions, improving the precision of brain death diagnosis in high-workload intensive care environments. We detail the implementation of a continuous multimodal neuromonitoring system, utilizing electrocorticography to monitor cortical spreading depolarizations (SD) and employing advanced analytics to track variability in heart and respiratory rates as indicators of brainstem functions. The SD-ICU single-center trial assessed the feasibility and safety of SD monitoring in patients with acute brain injuries, using cortical electrodes. In conjunction with the Moberg CNS monitor, this setup allowed for the collection and analysis of multimodal neuromonitoring data. We highlight the case of a patient who, exhibited an SD-initiated negative ultraslow potential, indicating cortical death. Subsequent fluctuations in heart and respiratory rates’ variability provided a real-time evaluation of the functionality of the brainstem's cardiovascular and respiratory centers. The integration of SD monitoring and variability analyses offers a continuous bedside evaluation, presenting clinicians with real-time biomarkers of brainstem and cortical death. This method could be incorporated into neuromonitoring software, enabling more timely and precise brain death determinations, a paramount improvement given the complexities and demands of ICU care.