The RAP Index during Intracranial Pressure Monitoring as a Clinical Guiding for Surgically Treated Aneurysmal Subarachnoid Hemorrhage: Consecutive Series of Single Surgeon

Continuous monitoring methods of cerebral compliance and compensatory reserve: a scoping review of human literature

Objective.Continuous monitoring of cerebrospinal compliance (CC)/cerebrospinal compensatory reserve (CCR) is crucial for timely interventions and preventing more substantial deterioration in the context of acute neural injury, as it enables the early detection of abnormalities in intracranial pressure (ICP). However, to date, the literature on continuous CC/CCR monitoring is scattered and occasionally challenging to consolidate.Approach.We subsequently conducted a systematic scoping review of the human literature to highlight the available continuous CC/CCR monitoring methods.Main results.This systematic review incorporated a total number of 76 studies, covering diverse patient types and focusing on three primary continuous CC or CCR monitoring metrics and methods-Moving Pearson's correlation between ICP pulse amplitude waveform and ICP, referred to as RAP, the Spiegelberg Compliance Monitor, changes in cerebral blood flow velocity with respect to the alternation of ICP measured through transcranial doppler (TCD), changes in centroid metric, high frequency centroid (HFC) or higher harmonics centroid (HHC), and the P2/P1 ratio which are the distinct peaks of ICP pulse wave. The majority of the studies in this review encompassed RAP metric analysis (n= 43), followed by Spiegelberg Compliance Monitor (n= 11), TCD studies (n= 9), studies on the HFC/HHC (n= 5), and studies on the P2/P1 ratio studies (n= 6). These studies predominantly involved acute traumatic neural injury (i.e. Traumatic Brain Injury) patients and those with hydrocephalus. RAP is the most extensively studied of the five focused methods and exhibits diverse applications. However, most papers lack clarification on its clinical applicability, a circumstance that is similarly observed for the other methods.Significance.Future directions involve exploring RAP patterns and identifying characteristics and artifacts, investigating neuroimaging correlations with continuous CC/CCR and integrating machine learning, holding promise for simplifying CC/CCR determination. These approaches should aim to enhance the precision and accuracy of the metric, making it applicable in clinical practice.

Intracranial pressure: current perspectives on physiology and monitoring

Intracranial pressure (ICP) monitoring is now viewed as integral to the clinical care of many life-threatening brain insults, such as severe traumatic brain injury, subarachnoid hemorrhage, and malignant stroke. It serves to warn of expanding intracranial mass lesions, to prevent or treat herniation events as well as pressure elevation which impedes nutrient delivery to the brain. It facilitates the calculation of cerebral perfusion pressure (CPP) and the estimation of cerebrovascular autoregulatory status. Despite advancements in our knowledge emanating from a half century of experience with this technology, important controversies remain related even to fundamental aspects of ICP measurements, including indications for monitoring, ICP treatment thresholds, and management of intracranial hypertension. Here, we review the history of ICP monitoring, the underlying pathophysiology as well as current perspectives on why, when and how ICP monitoring is best used. ICP is typically assessed invasively but a number of emerging, non-invasive technologies with inherently lower risk are showing promise. In selected cases, additional neuromonitoring can be used to assist in the interpretation of ICP monitoring information and adapt directed treatment accordingly. Additional efforts to expand the evidence base relevant to ICP monitoring, related technologies and management remain a high priority in neurosurgery and neurocritical care.

The application value of CT radiomics features in predicting pressure amplitude correlation index in patients with severe traumatic brain injury

Purpose

To explore the application value of a machine learning model based on CT radiomics features in predicting the pressure amplitude correlation index (RAP) in patients with severe traumatic brain injury (sTBI).

Methods

Retrospectively analyzed the clinical and imaging data in 36 patients with sTBI. All patients underwent surgical treatment, continuous ICP monitoring, and invasive arterial pressure monitoring. The pressure amplitude correlation index (RAP) was collected within 1 h after surgery. Three volume of interest (VOI) was selected from the craniocerebral CT images of patients 1 h after surgery, and a total of 93 radiomics features were extracted from each VOI. Three models were established to be used to evaluate the patients' RAP levels. The accuracy, precision, recall rate, F1 score, receiver operating characteristic (ROC) curve, and area under the curve (AUC) were used to evaluate the predictive performance of each model.

Results

The optimal number of features for three predicting models of RAP was five, respectively. The accuracy of predicting the model of the hippocampus was 77.78%, precision was 88.24%, recall rate was 60%, the F1 score was 0.6, and AUC was 0.88. The accuracy of predicting the model of the brainstem was 63.64%, precision was 58.33%, the recall rate was 60%, the F1 score was 0.54, and AUC was 0.82. The accuracy of predicting the model of the thalamus was 81.82%, precision was 88.89%, recall rate was 75%, the F1 score was 0.77, and AUC was 0.96.

Conclusions

CT radiomics can predict RAP levels in patients with sTBI, which has the potential to establish a method of non-invasive intracranial pressure (NI-ICP) monitoring.

Multimodal Neurologic Monitoring in Children With Acute Brain Injury

Children with acute neurologic illness are at high risk of mortality and long-term neurologic disability. Severe traumatic brain injury, cardiac arrest, stroke, and central nervous system infection are often complicated by cerebral hypoxia, hypoperfusion, and edema, leading to secondary neurologic injury and worse outcome. Owing to the paucity of targeted neuroprotective therapies for these conditions, management emphasizes close physiologic monitoring and supportive care. In this review, we will discuss advanced neurologic monitoring strategies in pediatric acute neurologic illness, emphasizing the physiologic concepts underlying each tool. We will also highlight recent innovations including novel monitoring modalities, and the application of neurologic monitoring in critically ill patients at risk of developing neurologic sequelae.