Practicalities of noninvasive neuromonitoring in intensive care

Noninvasive neuromonitoring provides valuable insights into cerebral physiology and function, with the potential to support individualized care for patients who are critically ill. As precision medicine continues to advance within the intensive care unit, the integration of multiple noninvasive monitoring techniques may offer a more comprehensive, real-time understanding of dynamic cerebral pathophysiology while avoiding the risks of invasive procedures. This study aimed to identify the implementation challenges of combining multiple noninvasive neuromonitoring modalities. Six modalities were selected: blind transcranial Doppler ultrasonography, optic nerve sheath diameter measurement, multichannel continuous electroencephalography (cEEG), automated pupillometry, near-infrared spectroscopy (NIRS), and skull extensometer (Brain4Care).

To assess the readiness of each modality for integration into a multimodal noninvasive monitoring setup, a group of experts propose the Noninvasive Neuromonitoring Multimodal Readiness (nnMR) score. This scoring system aims to provide a structured evaluation of each modality's multimodal suitability based on criteria such as data continuity and processing, physiological signal representation, spatial and temporal resolution, and software integration in the intensive care unit setting.

nnMR scores showed that cEEG and NIRS enable continuous monitoring without manual processing. Blind transcranial Doppler and NIRS offer a good temporal resolution; optic nerve sheath diameter provides good spatial resolution; cEEG and skull extensometer combine both. Only cEEG demonstrates anatomical clarity. Software integration remains limited across all modalities. Key challenges to multimodal implementation include the need for skilled personnel, artifact susceptibility, mismatched temporal and spatial resolutions, and limited long-term signal stability. Integration into unified analytical platforms is further constrained by a lack of standardization, requiring separate manual data input, processing, and quantification.

The nnMR score was developed to assess the current readiness of each modality for multimodal, continuous, and long-term clinical application. To validate the proposed nnMR score, engagement with the broader neurocritical care community is essential. Realizing the full potential of multimodal neuromonitoring will require advances in signal validation, software integration, resolution alignment, artifact detection, fixation techniques, and standardization, necessitating close collaboration among researchers, engineers, manufacturers, and clinicians.