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Brian L. Appavu, MD
Multimodality neurologic monitoring in neurocritical care refers to the use of frequent and continuous measures of brain physiology that can be obtained at the bedside to detect clinically important events in real time for patients with acute brain injury or at risk of brain injury. The integration of such physiologic data in a time-synchronized manner allows for a patient’s brain physiology to be better understood, compared to when multiple types of data are evaluated in isolation. Multimodality neurologic monitoring is increasingly being recognized as a useful tool in clinical decision support for neurocritical care. It represents an extension of the neurologic examination and clinical skill of bedside clinicians to better understand brain physiology in real time for patients with critical illnesses who may be comatose.
The goals of multimodality neurologic monitoring are to detect early signs of brain injury or worsening brain injury before irreversible brain damage takes place and to allow clinicians the opportunity to optimize neuroprotection for injured brain tissue that still has an opportunity to heal and recover. To that end, multimodality neurologic monitoring allows for:
- Detection of early signs of brain injury before irreversible brain damage takes place.
- Opportunity for neurocritical care teams to set individualized goals for blood pressure management, intracranial pressure and ventilation management for optimal brain health.
- Monitoring of the effectiveness of neuroprotective therapies.
- Enhancement of clinicians’ understanding of cerebrovascular pressure reactivity, carbon dioxide reactivity, brain compliance, cortical and corticothalamic function and autonomic function.
- Guidance in the design and implementation of clinical management and research protocols.
By adding value in this manner, the fundamental goal of multimodality neurologic monitoring is to help improve the outcomes and quality of life for either survivors of critical brain injury or survivors of critical illness at risk of brain injury (Figure 1).
Figure 1: Example of multimodality neurologic monitoring data visualization in neurocritical care
Existing Challenges in Pediatric Neurocritical Care
Secondary brain injury can result in the hours and days following an initial brain injury. During this time, changes in the neural cellular injury cascade or secondary brain insults – such as cerebral edema, brain tissue hypoxia or aberrant cerebral blood flow – can contribute to the extent of such brain injury. While published and institutional guidelines exist to maximize care for the greatest number of patients, there is recognition that every patient is unique, and many may require their own distinct parameters to optimize their overall care. This is especially true for children, where age, genetics and many other factors may add to the need for personalized medicine.
Multiple neurologic monitoring tools can be used in the neurocritical care environment to monitor for secondary brain injury, including continuous electroencephalography, transcranial Doppler ultrasound, pupillometry, brain tissue oxygenation monitoring and intracranial pressure (ICP) monitoring. Each of these tools, in isolation, gives a limited window into real-time physiology. By integrating all these tools in real time, clinicians are better equipped to develop broader insights into brain physiology. Furthermore, advanced calculation of model-based indices of cerebrovascular pressure reactivity, brain compliance and autonomic function allows physicians to better understand what specific parameters may be used in patient care to promote optimal brain health and recovery.
Real-Time Analysis at Phoenix Children’s
The Neurocritical Care Program at the Barrow Neurological Institute at Phoenix Children’s utilizes six multimodality neurologic monitoring units that are available for use within the health system’s pediatric, cardiac and neonatal intensive care units. These devices time-synchronize all brain and systemic monitoring tools at high temporal resolution with raw waveforms available for analysis. The data is archived in a clinical database, and network ports are available for streaming data in real time across the health system’s network so that clinicians, at the bedside, in the operating room and throughout the health system, can look at changes in brain physiology for their patients. Using advanced software, the data can be used to calculate model-based indices of cerebral dynamics that allow physicians to understand, at any given time, what may be a patient’s clinical state, as well as their optimal blood pressure or ventilatory targets.
Research, Education and Future Directions
The ability to collect and store high-resolution physiologic data of children with critical illnesses allows a unique opportunity for scientists to investigate for biomarkers of worsening brain injury and brain recovery. Over the past six years, we have successfully obtained investigator-initiated funds from United States Department of Defense, the American Heart Association and the Pediatric Epilepsy Research Foundation. We have developed and published predictive models to forecast early posttraumatic seizures and intracranial hypertension and have refined physiologic biomarkers that predict post-traumatic epilepsy, functional outcomes after traumatic brain injury and brain injury for children requiring extracorporeal membrane oxygenation support1,2,3,4.
As a leader in multimodality neurologic monitoring, we participate in large multicenter consortiums and provide educational lectures on the latest evidence and clinical practices in neuromonitoring (https://vimeo.com/850917122). Through our pediatric neurocritical care fellowship, we train the next generation of physicians in advanced practices of neuromonitoring. As more pediatric and adult neurocritical care centers adopt multimodality neurologic monitoring for both clinical care and research, we seek to harness and strengthen our collaborations both nationally and internationally to conduct larger prospective studies. Overall, the future looks promising for finding novel ways of improving care for children with critical illnesses.
- Appavu BL, Temkit M’, Kensicki JF, et al. Acute physiologic prediction of pediatric post-traumatic epilepsy. Epilepsy Res. 2022 Jul;183:106935. doi: 10.1016/j.eplepsyres.2022.106935. PMID: 35526326
- Appavu B, Temkit M’, Foldes S, et al. Association of Outcomes with Model-Based Indices of Cerebral Autoregulation after Pediatric Traumatic Brain Injury. Neurocrit Care. 2021 Dec;35(3):640-650. doi: 10.1007/s12028—021-01279-0. PMID: 34268644
- Xie J, Burrows BT, Kensicki JF, et al. Early Electroencephalographic Features Predicting Cerebral Physiology and Functional Outcomes After Pediatric Traumatic Brain Injury. Neurocrit Care. 2023 Jun;28(3):367-666. doi: 10.1007/s12028-022-01633-w. PMID: 36329306
- Hanalioglu D, Temkit M’, Hildebrandt K, et al. Neurophysiologic Features Reflecting Brain Injury During ECMO Support. Neuorcrit Care. Article in Press, 2023. soi: 10.1007/s12028-023-01836-9.