A trial of intracranial-pressure monitoring in traumatic brain injury

Brain Trauma and the Secondary Cascade in Humans: Review of the Potential Role of Vitamins in Reparative Processes and Functional Outcome

An estimated sixty-nine million people sustain a traumatic brain injury each year. Trauma to the brain causes the primary insult and initiates a secondary biochemical cascade as part of the immune and reparative response to injury. The secondary cascade, although a normal physiological response, may also contribute to ongoing neuroinflammation, oxidative stress and axonal injury, continuing in some cases years after the initial insult. In this review, we explain some of the biochemical mechanisms of the secondary cascade and their potential deleterious effects on healthy neurons including secondary cell death. The second part of the review focuses on the role of micronutrients to neural mechanisms and their potential reparative effects with regards to the secondary cascade after brain injury. The biochemical response to injury, hypermetabolism and excessive renal clearance of nutrients after injury increases the demand for most vitamins. Currently, most research in the area has shown positive outcomes of vitamin supplementation after brain injury, although predominantly in animal (murine) models. There is a pressing need for more research in this area with human participants because vitamin supplementation post-trauma is a potential cost-effective adjunct to other clinical and therapeutic treatments. Importantly, traumatic brain injury should be considered a lifelong process and better evaluated across the lifespan of individuals who experience brain injury.

[Individualized treatment in anesthesiology and intensive care medicine]

BACKGROUND

Individualized medicine uses data on biological characteristics of individual patients in order to tailor treatment planning to their unique constitution. With respect to the practice of anesthesiology and intensive care medicine, it bears the potential to systematize the often complex medical care of critically ill patients and to improve outcomes.

OBJECTIVE

The aim of this narrative review is to provide an overview of the possible applications of the principles of individualized medicine in anesthesiology and intensive care medicine.

MATERIAL AND METHODS

Based on a search in MEDLINE, CENTRAL and Google Scholar, the results of previous studies and systematic reviews are narratively synthesized and the implications for the scientific and clinical practice are presented.

RESULTS AND DISCUSSION

There are possibilities for individualization and an increase in precision of patient care in most if not all problems in anesthesiology and symptoms in intensive medical care. Even now, all practicing physicians can initiate measures to individualize treatment at different timepoints throughout the course of treatment. Individualized medicine can supplement and be integrated into protocols. Plans for future applications of individualized medicine interventions should consider the feasibility in a real-world setting. Clinical studies should contain process evaluations in order to create ideal preconditions for a successful implementation. Quality management, audits and feedback should become a standard procedure to ensure sustainability. In the long run, individualization of care, especially in the critically ill, should be enshrined in guidelines and become an integral part of clinical practice.

Multimodal and autoregulation monitoring in the neurointensive care unit

Given the complexity of cerebral pathology in patients with acute brain injury, various neuromonitoring strategies have been developed to better appreciate physiologic relationships and potentially harmful derangements. There is ample evidence that bundling several neuromonitoring devices, termed "multimodal monitoring," is more beneficial compared to monitoring individual parameters as each may capture different and complementary aspects of cerebral physiology to provide a comprehensive picture that can help guide management. Furthermore, each modality has specific strengths and limitations that depend largely on spatiotemporal characteristics and complexity of the signal acquired. In this review we focus on the common clinical neuromonitoring techniques including intracranial pressure, brain tissue oxygenation, transcranial doppler and near-infrared spectroscopy with a focus on how each modality can also provide useful information about cerebral autoregulation capacity. Finally, we discuss the current evidence in using these modalities to support clinical decision making as well as potential insights into the future of advanced cerebral homeostatic assessments including neurovascular coupling.

Can a new noninvasive method for assessment of intracranial pressure predict intracranial hypertension and prognosis?

PURPOSE

Individuals with TBI are at risk of intracranial hypertension (ICH), and monitoring of intracranial pressure (ICP) is usually indicated. However, despite many new noninvasive devices, none is sufficiently accurate and effective for application in clinical practice, particularly in the management of TBIs. This study aimed to compare the noninvasive Brain4Care system (nICP) with invasive ICP (iICP) curve parameters in their ability to predict ICH and functional prognosis in severe TBI.

METHODS

Observational, descriptive-analytical, and prospective study of 22 patients between 2018 and 2021, simultaneously monitored with nICP and iICP. The independent variables evaluated were the presence of ICH and functional prognoses. The dependent variables were the P2/P1 pressure ratio metrics, time to peak (TTP), and TTP × P2/P1.

RESULTS

We found a good nonlinear correlation between iICP and nICP waveforms, despite a moderate Pearson's linear correlation. The noninvasive parameters of P2/P1, P2/P1 × TTP, and TTP were not associated with outcomes or ICH. The nICP P2/P1 ratio showed sensitivity/specificity/accuracy (%) of 100/0/56.3, respectively for 1-month outcomes and 77.8/22.2/50 for 6-month outcomes. The nICP TTP ratio had values of 100/0/56.3 for 1-month and 99.9/42.9/72.2 for 6-month outcomes. The nICP P2/P1 × TTP values were 100/0/56.3 for 1-month outcomes and 81.8/28.6/61.1 for 6-month outcomes.

CONCLUSION

Brain4Care's noninvasive method showed low specificity and accuracy and cannot be used as the sole means of monitoring ICP in patients with severe TBI. Future studies with a larger sample of patients with P2 > P1 and new nICP curve parameters are warranted.

The intracranial compartmental syndrome: a proposed model for acute brain injury monitoring and management

For decades, one of the main targets in the management of severe acute brain injury (ABI) has been intracranial hypertension (IH) control. However, the determination of IH has suffered variations in its thresholds over time without clear evidence for it. Meanwhile, progress in the understanding of intracranial content (brain, blood and cerebrospinal fluid) dynamics and recent development in monitoring techniques suggest that targeting intracranial compliance (ICC) could be a more reliable approach rather than guiding actions by predetermined intracranial pressure values. It is known that ICC impairment forecasts IH, as intracranial volume may rapidly increase inside the skull, a closed bony box with derisory expansibility. Therefore, an intracranial compartmental syndrome (ICCS) can occur with deleterious brain effects, precipitating a reduction in brain perfusion, thereby inducing brain ischemia. The present perspective review aims to discuss the ICCS concept and suggest an integrative model for the combination of modern invasive and noninvasive techniques for IH and ICC assessment. The theory and logic suggest that the combination of multiple ancillary methods may enhance ICC impairment prediction, pointing proactive actions and improving patient outcomes.

Current status and outlook for the management of intracranial hypertension after traumatic brain injury: decompressive craniectomy, therapeutic hypothermia, and barbiturates

INTRODUCTION

Increased intracranial pressure (ICP) has been associated with poor neurological outcomes and increased mortality in patients with severe traumatic brain injury (TBI). Traditionally, ICP-lowering therapies are administered using an escalating approach, with more aggressive options reserved for patients showing no response to first-tier interventions, or with refractory intracranial hypertension.

DEVELOPMENT

The therapeutic value and the appropriate timing for the use of rescue treatments for intracranial hypertension have been a subject of constant debate in literature. In this review, we discuss the main management options for refractory intracranial hypertension after severe TBI in adults. We intend to conduct an in-depth revision of the most representative randomised controlled trials on the different rescue treatments, including decompressive craniectomy, therapeutic hypothermia, and barbiturates. We also discuss future perspectives for these management options.

CONCLUSIONS

The available evidence appears to show that mortality can be reduced when rescue interventions are used as last-tier therapy; however, this benefit comes at the cost of severe disability. The decision of whether to perform these interventions should always be patient-centred and made on an individual basis. The development and integration of different physiological variables through multimodality monitoring is of the utmost importance to provide more robust prognostic information to patients facing these challenging decisions.

A Machine Learning Approach for Predicting Real-time Risk of Intraoperative Hypotension in Traumatic Brain Injury

BACKGROUND

Traumatic brain injury (TBI) is a major cause of death and disability. Episodes of hypotension are associated with worse TBI outcomes. Our aim was to model the real-time risk of intraoperative hypotension in TBI patients, compare machine learning and traditional modeling techniques, and identify key contributory features from the patient monitor and medical record for the prediction of intraoperative hypotension.

METHODS

The data included neurosurgical procedures in 1005 TBI patients at an academic level 1 trauma center. The clinical event was intraoperative hypotension, defined as mean arterial pressure <65 mm Hg for 5 or more consecutive minutes. Two types of models were developed: one based on preoperative patient-level predictors and one based on intraoperative predictors measured per minute. For each of these models, we took 2 approaches to predict the occurrence of a hypotensive event: a logistic regression model and a gradient boosting tree model.

RESULTS

The area under the receiver operating characteristic curve for the intraoperative logistic regression model was 0.80 (95% confidence interval [CI]: 0.78-0.83), and for the gradient boosting model was 0.83 (95% CI: 0.81-0.85). The area under the precision-recall curve for the intraoperative logistic regression model was 0.16 (95% CI: 0.12-0.20), and for the gradient boosting model was 0.19 (95% CI: 0.14-0.24). Model performance based on preoperative predictors was poor. Features derived from the recent trend of mean arterial pressure emerged as dominantly predictive in both intraoperative models.

CONCLUSIONS

This study developed a model for real-time prediction of intraoperative hypotension in TBI patients, which can use computationally efficient machine learning techniques and a streamlined feature-set derived from patient monitor data.

Beyond intracranial pressure: monitoring cerebral perfusion and autoregulation in severe traumatic brain injury

PURPOSE OF REVIEW

Severe traumatic brain injury (TBI) remains the most prevalent neurological condition worldwide. Observational and interventional studies provide evidence to recommend monitoring of intracranial pressure (ICP) in all severe TBI patients. Existing guidelines focus on treating elevated ICP and optimizing cerebral perfusion pressure (CPP), according to fixed universal thresholds. However, both ICP and CPP, their target thresholds, and their interaction, need to be interpreted in a broader picture of cerebral autoregulation, the natural capacity to adjust cerebrovascular resistance to preserve cerebral blood flow in response to external stimuli.

RECENT FINDINGS

Cerebral autoregulation is often impaired in TBI patients, and monitoring cerebral autoregulation might be useful to develop personalized therapy rather than treatment of one size fits all thresholds and guidelines based on unidimensional static relationships.

SUMMARY

Today, there is no gold standard available to estimate cerebral autoregulation. Cerebral autoregulation can be triggered by performing a mean arterial pressure (MAP) challenge, in which MAP is increased by 10% for 20 min. The response of ICP (increase or decrease) will estimate the status of cerebral autoregulation and can steer therapy mainly concerning optimizing patient-specific CPP. The role of cerebral metabolic changes and its relationship to cerebral autoregulation is still unclear and awaits further investigation.

Management of traumatic brain injury in the non-neurosurgical intensive care unit: a narrative review of current evidence

Each year, approximately 70 million people suffer traumatic brain injury, which has a significant physical, psychosocial and economic impact for patients and their families. It is recommended in the UK that all patients with traumatic brain injury and a Glasgow coma scale ≤ 8 should be transferred to a neurosurgical centre. However, many patients, especially those in whom neurosurgery is not required, are not treated in, nor transferred to, a neurosurgical centre. This review aims to provide clinicians who work in non-neurosurgical centres with a summary of contemporary studies relevant to the critical care management of patients with traumatic brain injury. A targeted literature review was undertaken that included guidelines, systematic reviews, meta-analyses, clinical trials and randomised controlled trials (published in English between 1 January 2017 and 1 July 2022). Studies involving key clinical management strategies published before this time, but which have not been updated or repeated, were also eligible for inclusion. Analysis of the topics identified during the review was then summarised. These included: fundamental critical care management approaches (including ventilation strategies, fluid management, seizure control and osmotherapy); use of processed electroencephalogram monitoring; non-invasive assessment of intracranial pressure; prognostication; and rehabilitation techniques. Through this process, we have formulated practical recommendations to guide clinical practice in non-specialist centres.

Neuromonitoring in Critically Ill Patients

OBJECTIVES

Critically ill patients are at high risk of acute brain injury. Bedside multimodality neuromonitoring techniques can provide a direct assessment of physiologic interactions between systemic derangements and intracranial processes and offer the potential for early detection of neurologic deterioration before clinically manifest signs occur. Neuromonitoring provides measurable parameters of new or evolving brain injury that can be used as a target for investigating various therapeutic interventions, monitoring treatment responses, and testing clinical paradigms that could reduce secondary brain injury and improve clinical outcomes. Further investigations may also reveal neuromonitoring markers that can assist in neuroprognostication. We provide an up-to-date summary of clinical applications, risks, benefits, and challenges of various invasive and noninvasive neuromonitoring modalities.

DATA SOURCES

English articles were retrieved using pertinent search terms related to invasive and noninvasive neuromonitoring techniques in PubMed and CINAHL.

STUDY SELECTION

Original research, review articles, commentaries, and guidelines.

DATA EXTRACTION

Syntheses of data retrieved from relevant publications are summarized into a narrative review.

DATA SYNTHESIS

A cascade of cerebral and systemic pathophysiological processes can compound neuronal damage in critically ill patients. Numerous neuromonitoring modalities and their clinical applications have been investigated in critically ill patients that monitor a range of neurologic physiologic processes, including clinical neurologic assessments, electrophysiology tests, cerebral blood flow, substrate delivery, substrate utilization, and cellular metabolism. Most studies in neuromonitoring have focused on traumatic brain injury, with a paucity of data on other clinical types of acute brain injury. We provide a concise summary of the most commonly used invasive and noninvasive neuromonitoring techniques, their associated risks, their bedside clinical application, and the implications of common findings to guide evaluation and management of critically ill patients.

CONCLUSIONS

Neuromonitoring techniques provide an essential tool to facilitate early detection and treatment of acute brain injury in critical care. Awareness of the nuances of their use and clinical applications can empower the intensive care team with tools to potentially reduce the burden of neurologic morbidity in critically ill patients.

Accuracy of Intracranial Pressure Monitoring-Single Centre Observational Study and Literature Review

Intracranial hypertension and adequacy of brain blood flow are primary concerns following traumatic brain injury. Intracranial pressure (ICP) monitoring is a critical diagnostic tool in neurocritical care. However, all ICP sensors, irrespective of design, are subject to systematic and random measurement inaccuracies that can affect patient care if overlooked or disregarded. The wide choice of sensors available to surgeons raises questions about performance and suitability for treatment. This observational study offers a critical review of the clinical and experimental assessment of ICP sensor accuracy and comments on the relationship between actual clinical performance, bench testing, and manufacturer specifications. Critically, on this basis, the study offers guidelines for the selection of ICP monitoring technologies, an important clinical decision. To complement this, a literature review on important ICP monitoring considerations was included. This study utilises illustrative clinical and laboratory material from 1200 TBI patients (collected from 1992 to 2019) to present several important points regarding the accuracy of in vivo implementation of contemporary ICP transducers. In addition, a thorough literature search was performed, with sources dating from 1960 to 2021. Sources considered to be relevant matched the keywords: "intraparenchymal ICP sensors", "fiberoptic ICP sensors", "piezoelectric strain gauge sensors", "external ventricular drains", "CSF reference pressure", "ICP zero drift", and "ICP measurement accuracy". Based on single centre observations and the 76 sources reviewed in this paper, this material reports an overall anticipated measurement accuracy for intraparenchymal transducers of around ± 6.0 mm Hg with an average zero drift of <2.0 mm Hg. Precise ICP monitoring is a key tenet of neurocritical care, and accounting for zero drift is vital. Intraparenchymal piezoelectric strain gauge sensors are commonly implanted to monitor ICP. Laboratory bench testing results can differ from in vivo observations, revealing the shortcomings of current ICP sensors.

Traumatic Brain Injury in Select Low- and Middle-Income Countries: A Narrative Review of the Literature

Low- and middle-income countries (LMICs) experience the majority of traumatic brain injuries (TBIs), yet few studies have examined the epidemiology and management strategies of TBI in LMICs. The objective of this narrative review is to discuss the epidemiology of TBI within LMICs, describe the adherence to Brain Trauma Foundation (BTF) guidelines for the management of severe TBI in LMICs, and document TBI management strategies currently used in LMICs. Articles from January 1, 2009 to September 30, 2021 that included patients with TBI greater than 18 years of age in low-, low middle-, and high middle-income countries were queried in PubMed. Search results demonstrated that TBI in LMICs mostly impacts young males involved in road traffic accidents. Within LMICs there are a myriad of approaches to managing TBI with few randomized controlled trials performed within LMICs to evaluate those interventions. More studies are needed in LMICs to establish the effectiveness and appropriateness of BTF guidelines for managing TBI and to help identify methods for managing TBI that are appropriate in low-resource settings. The problem of limited pre- and post-hospital care is a bigger challenge that needs to be considered while addressing management of TBI in LMICs.

Traumatic Brain Injury: Intraoperative Management and Intensive Care Unit Multimodality Monitoring

Traumatic brain injury is a devastating event associated with substantial morbidity. Pathophysiology involves the initial trauma, subsequent inflammatory response, and secondary insults, which worsen brain injury severity. Management entails cardiopulmonary stabilization and diagnostic imaging with targeted interventions, such as decompressive hemicraniectomy, intracranial monitors or drains, and pharmacological agents to reduce intracranial pressure. Anesthesia and intensive care requires control of multiple physiologic variables and evidence-based practices to reduce secondary brain injury. Advances in biomedical engineering have enhanced assessments of cerebral oxygenation, pressure, metabolism, blood flow, and autoregulation. Many centers employ multimodality neuromonitoring for targeted therapies with the hope to improve recovery.

Testing the Impact of Protocolized Care of Patients With Severe Traumatic Brain Injury Without Intracranial Pressure Monitoring: The Imaging and Clinical Examination Protocol

BACKGROUND

Most patients with severe traumatic brain injury (sTBI) in low- or-middle-income countries and surprisingly many in high-income countries are managed without intracranial pressure (ICP) monitoring. The impact of the first published protocol (Imaging and Clinical Examination [ICE] protocol) is untested against nonprotocol management.

OBJECTIVE

To determine whether patients treated in intensive care units (ICUs) using the ICE protocol have lower mortality and better neurobehavioral functioning than those treated in ICUs using no protocol.

METHODS

This study involved nineteen mostly public South American hospitals. This is a prospective cohort study, enrolling patients older than 13 years with sTBI presenting within 24 h of injury (January 2014-July 2015) with 6-mo postinjury follow-up. Five hospitals treated all sTBI cases using the ICE protocol; 14 used no protocol. Primary outcome was prespecified composite of mortality, orientation, functional outcome, and neuropsychological measures.

RESULTS

A total of 414 patients (89% male, mean age 34.8 years) enrolled; 81% had 6 months of follow-up. All participants included in composite outcome analysis: average percentile (SD) = 46.8 (24.0) nonprotocol, 56.9 (24.5) protocol. Generalized estimating equation (GEE) used to account for center effects (confounder-adjusted difference [95% CI] = 12.2 [4.6, 19.8], P = .002). Kaplan-Meier 6-month mortality (95% CI) = 36% (30%, 43%) nonprotocol, 25% (19%, 31%) protocol (GEE and confounder-adjusted hazard ratio [95% CI] = .69 [.43, 1.10], P = .118). Six-month Extended Glasgow Outcome Scale for 332 participants: average Extended Glasgow Outcome Scale score (SD) = 3.6 (2.6) nonprotocol, 4.7 (2.8) protocol (GEE and confounder-adjusted and lost to follow-up-adjusted difference [95% CI] = 1.36 [.55, 2.17], P = .001).

CONCLUSION

ICUs managing patients with sTBI using the ICE protocol had better functional outcome than those not using a protocol. ICUs treating patients with sTBI without ICP monitoring should consider protocolization. The ICE protocol, tested here and previously, is 1 option.

Noninvasive intracranial pressure monitoring in central nervous system infections

Intracranial pressure (ICP) monitoring constitutes an important part of the management of traumatic brain injury. However, its application in other brain pathologies such as neuroinfections like acute bacterial meningitis is unclear. Despite focus on aggressive, prompt treatment, morbidity and mortality from acute bacterial meningitis remain high. Increased ICP is well-known to occur in severe neuroinfections. The increased ICP compromise cerebral perfusion pressure and may ultimately lead to brain stem herniation. Therefore, controlling the ICP could also be important in acute bacterial meningitis. However, risk factors for complications due to invasive monitoring among these patients may be significantly increased due to higher age and levels of comorbidity compared to the traumatic brain injury patient from which the ICP treatment algorithms are developed. This narrative review evaluates the different modalities of ICP monitoring with the aim to elucidate current status of non-invasive alternatives to invasive monitoring as a decision tool and eventually monitoring. Non-invasive screening using ultrasound of the optical nerve sheath, transcranial doppler, magnetic resonance imaging or preferably a combination of these modalities, provides measurements that can be used as a decision guidance for invasive ICP measurement. The available data do not support the replacement of invasive techniques for continuous ICP measurement in patients with increased ICP. Non-invasive modalities should be taken into consideration in patients with neuroinfections at low risk of increased ICP.

Development of Traumatic Brain Injury Associated Intracranial Hypertension Prediction Algorithms: A Narrative Review

Traumatic intracranial hypertension (tIH) is a common and potentially lethal complication of moderate to severe traumatic brain injury (m-sTBI). It often develops with little warning and is managed reactively with the tiered application of intracranial pressure (ICP)-lowering interventions administered in response to an ICP rising above a set threshold. For over 45 years, a variety of research groups have worked toward the development of technology to allow for the preemptive management of tIH in the hope of improving patient outcomes. In 2022, the first operationalizable tIH prediction system became a reality. With such a system, ICP lowering interventions could be administered prior to the rise in ICP, thus protecting the patient from potentially damaging tIH episodes and limiting the overall ICP burden experienced. In this review, we discuss related approaches to ICP forecasting and IH prediction algorithms, which collectively provide the foundation for the successful development of an operational tIH prediction system. We also discuss operationalization and the statistical assessment of tIH algorithms. This review will be of relevance to clinicians and researchers interested in development of this technology as well as those with a general interest in the bedside application of machine learning (ML) technology.

Invasive Neuromonitoring in the Stroke Patient

With advances in technology, the options to manage patients with neurologic injuries are often complex. Critical care management of neurologic injury has historically focused on the prevention of secondary ischemic injury through aggressive management of intracranial pressure (ICP) and maintenance of adequate cerebral perfusion pressure (CPP). However, ICP monitoring alone does not identify ischemic changes that herald patient deterioration. Advocates of multimodality monitoring cite the value of early detection of changes in brain oxygenation levels and brain metabolism as advantageous in optimizing stroke outcomes. ICP monitoring alone should not be the sole source of information on which therapy is guided but should be incorporated into the arsenal of emerging and promising invasive neuromonitoring devices.

An overview of clinical cerebral microdialysis in acute brain injury

Cerebral microdialysis may be used in patients with severe brain injury to monitor their cerebral physiology. In this article we provide a concise synopsis with illustrations and original images of catheter types, their structure, and how they function. Where and how catheters are inserted, their identification on imaging modalities (CT and MRI), together with the roles of glucose, lactate/pyruvate ratio, glutamate, glycerol and urea are summarized in acute brain injury. The research applications of microdialysis including pharmacokinetic studies, retromicrodialysis, and its use as a biomarker for efficacy of potential therapies are outlined. Finally, we explore limitations and pitfalls of the technique, as well as potential improvements and future work that is needed to progress and expand the use of this technology.

Challenges in the Treatment of Severe Traumatic Brain Injury Based on Data in the Japan Neurotrauma Data Bank

The Japan Neurotrauma Data Bank is a source of epidemiological data for patients with severe traumatic brain injury (TBI) and is sponsored by the Japan Society of Neurotraumatology. In this report, we examined the changes in the treatment of severe TBI in Japan based on data of the Japan Neurotrauma Data Bank. Controlling and decreasing intracranial pressure (ICP) are the primary objective of severe TBI treatment. Brain-oriented whole-body control or neurocritical care, including control of cerebral perfusion pressure, respiration, and infusion, are also increasingly considered important because cerebral tissues require oxygenation to improve the outcomes of patients with severe TBI. The introduction of neurocritical care in Japan was delayed compared with that in Western countries. However, the rate of ICP monitoring increased from 28.0% in 2009 to 36.7% in 2015 and is currently likely to be higher. Neurocritical care has also become more common, but the functional prognosis of patients has not significantly improved in Japan. Changes in the background of patients with severe TBI suggest the need for improvement of acute-phase treatment for elderly patients. Appropriate social rehabilitation from the subacute to chronic phases and introduction of cellular therapeutics are also needed for patients with TBI.

Avoiding brain hypoxia in severe traumatic brain injury in settings with limited resources - A pathophysiological guide

Cerebral oxygenation represents the balance between oxygen delivery, consumption and utilization by the brain, and therefore reflects the adequacy of cerebral perfusion. Different factors can influence the amount of oxygen to the brain including arterial blood pressure, hemoglobin levels, systemic oxygenation, and transfer of oxygen from blood to the cerebral microcirculation. A mismatch between cerebral oxygen supply and demand results in cerebral hypoxia/ischemia, and is associated with secondary brain damage and worsened outcome after acute brain injury. Therefore, monitoring and prompt treatment of cerebral oxygenation compromise is warranted in both neuro and general intensive care unit populations. Several tools have been proposed for the assessment of cerebral oxygenation, including non-invasive/invasive or indirect/direct methods, including Jugular Venous Oxygen Saturation (SjO2), Partial Brain Tissue Oxygen Tension (PtiO2), Near infrared spectroscopy (NIRS), Transcranial Doppler, electroencephalography and Computed Tomography. In this manuscript, we aim to review the pathophysiology of cerebral oxygenation, describe monitoring technics, and generate recommendations for avoiding brain hypoxia in settings with low availability of resources for direct brain oxygen monitoring.

Permutation Entropy Analysis to Intracranial Hypertension from a Porcine Model

Intracranial pressure (ICP) monitoring is commonly used in the follow-up of patients in intensive care units, but only a small part of the information available in the ICP time series is exploited. One of the most important features to guide patient follow-up and treatment is intracranial compliance. We propose using permutation entropy (PE) as a method to extract non-obvious information from the ICP curve. We analyzed the results of a pig experiment with sliding windows of 3600 samples and 1000 displacement samples, and estimated their respective PEs, their associated probability distributions, and the number of missing patterns (NMP). We observed that the behavior of PE is inverse to that of ICP, in addition to the fact that NMP appears as a surrogate for intracranial compliance. In lesion-free periods, PE is usually greater than 0.3, and normalized NMP is less than 90% and p(s1)>p(s720). Any deviation from these values could be a possible warning of altered neurophysiology. In the terminal phases of the lesion, the normalized NMP is higher than 95%, and PE is not sensitive to changes in ICP and p(s720)>p(s1). The results show that it could be used for real-time patient monitoring or as input for a machine learning tool.

Intracranial peak pressure as a predictor for perioperative mortality after spontaneous intracerebral hemorrhage evacuation and decompressive craniectomy

BACKGROUND

An optimal intracranial pressure (ICP) management target is not well defined in patients with spontaneous intracerebral hemorrhage. The aim of this study was to explore the association between perioperative ICP monitoring parameters and mortality of patients with spontaneous intracerebral hematoma undergoing emergency hematoma removal and decompressive craniectomy (DC), to provide evidence for a target-oriented ICP management.

METHODS

The clinical and radiological features of 176 consecutive patients with spontaneous intracerebral hemorrhage that underwent emergent hematoma evacuation and DC were reviewed. The Glasgow Coma Scale (GCS) and Glasgow Outcome Scale (GOS) scores were assessed 2 weeks after surgery. Multivariate logistic regression analysis was performed to identify predictors for perioperative death.

RESULTS

Forty-four cases (25.0%) were assigned to the ICP group. In patients with an ICP monitor, the median peak ICP value was 25.5 mmHg; 50% of them had a peak ICP value of more than 25 mmHg. The median duration of ICP > 25 mmHg was 2 days. Without a target-specific ICP management, the mortality at 2 weeks after surgery was similar between patients with or without an ICP monitor (27.3% versus 18.2%, p = 0.20). In multivariable analysis, the peak ICP value (OR 1.11, 95% CI 1.004-1.234, p = 0.04) was significantly associated with perioperative death in the ICP group. The area under ROC curve of peak ICP value was 0.78 (95%CI 0.62-0.94) for predicting mortality, with a cut-off value of 31 mmHg.

CONCLUSION

Compared with a persistent hyperintracranial pressure, a high ICP peak value might provide a better prediction for the mortality of patients with spontaneous intracerebral hemorrhage evacuation and DC, suggesting a tailored ICP management protocol to decrease ICP peak value.

Managing Severe Traumatic Brain Injury Across Resource Settings: Latin American Perspectives

Severe traumatic brain injury (sTBI) is a condition of increasing epidemiologic concern worldwide. Outcomes are worse as observed in low- and middle-income countries (LMICs) versus high-income countries. Global targets are in place to address the surgical burden of disease. At the same time, most of the published literature and evidence on the clinical approach to sTBI comes from wealthy areas with an abundance of resources. The available paradigms, including the Brain Trauma Foundation guidelines, the Seattle International Severe Traumatic Brain Injury Consensus Conference, Consensus Revised Imaging and Clinical Examination, and multimodality approaches, may fit differently depending on local resources, expertise, and sociocultural factors. A first step toward addressing heterogeneity in practice is to consider comparative effectiveness approaches that can capture actual practice patterns and record short-term and long-term outcomes of interest. Decompressive craniectomy (DC) decreases intracranial pressure burden and can be lifesaving. Nevertheless, completed randomized controlled trials took place within high-income settings, leaving important questions unanswered and making extrapolations to LMICs questionable. The concept of preemptive DC specifically to address limited neuromonitoring resources may warrant further study to establish a benefit/risk profile for the procedure and its role within local protocols of care.

Racial Disparity in Placement of Intracranial Pressure Monitoring: A TQIP Analysis

BACKGROUND

The Brain Trauma Foundation recommends intracranial pressure (ICP) monitoring in patients with severe traumatic brain injury (TBI). Race is associated with worse outcomes after TBI. The reasons for racial disparities in clinical decision-making around ICP monitor placement remain unclear.

STUDY DESIGN

We queried the TQIP database from 2017 to 2019 and included patients 16 years or older, with blunt severe TBI, defined as a head abbreviated injury score 3 or greater. Exclusion criteria were missing race, those without signs of life on admission, length of stay 1 day or less, and AIS of 6 in any body region. The primary outcome was ICP monitor placement, which was calculated using a Poisson regression model with robust SEs while adjusting for confounders.

RESULTS

A total of 260,814 patients were included: 218,939 White, 29,873 Black, 8,322 Asian, 2,884 American Indian, and 796 Native Hawaiian or Other Pacific Islander. Asian and American Indian patients had the highest rates of midline shift (16.5% and 16.9%). Native Hawaiian or Other Pacific Islanders had the highest rates of neurosurgical intervention (19.3%) and ICP monitor placement (6.5%). Asian patients were found to be 19% more likely to receive ICP monitoring (adjusted incident rate ratio 1.19; 95% CI 1.06 to 1.33; p = 0.003], and American Indian patients were 38% less likely (adjusted incident rate ratio 0.62; 95% CI 0.49 to 0.79; p < 0.001), compared with White patients, respectively. No differences were detected between White and Black patients.

CONCLUSIONS

ICP monitoring use differs by race. Further work is needed to elucidate modifiable causes of this difference in the management of severe TBI.

Fact-Finding Survey of Treatment of Traumatic Brain Injury in Japan: Standardization of Care and Collaboration Between Neurosurgery and Emergency Departments

BACKGROUND

Standardization of seamless treatment from prehospital injury care to initial injury and specialized care through collaboration among departments have been promoted in Japan since 2000. This survey was conducted to examine the current status of the system for treatment of traumatic brain injury (TBI) in Japan.

METHODS

In February 2022, questionnaires on the treatment system and TBI care were sent to 869 facilities that participated in a training program held by the Japan Neurosurgical Society. Responses were received from 480 facilities (55.2%). These responses were compared with those in a similar survey performed in 2008.

RESULTS

Among the responding facilities, 39.4% had neurosurgeons in emergency departments. Initial care for TBI was the responsibility of the neurosurgery department in 42.3% of the facilities, the emergency department in 26.0%, and jointly between these departments in 29.6%; and neurocritical care was managed by the neurosurgery department in 81.9%, the emergency department in 5.2%, and jointly in 12.1%. For patients with acute-phase TBI, intracranial pressure monitoring was performed in 72.1%. Active normothermia was performed in 86.0%, and decompressive craniectomy in 99.4%, as required. There was compliance with guidelines for treatment and management of TBI in 93.3%.

CONCLUSIONS

Comparison with the 2008 results suggested role-sharing between 2 departments in TBI treatment is increasing. TBI treatment compliance with the guidelines was high. In-hospital mortality of Japanese patients with TBI has decreased since 2000. This may be due to the progress with standardization of TBI treatment and collaboration among departments in compliance with guidelines.

Correlation between intracranial pressure monitoring for severe traumatic brain injury with hospital length of stay and discharge disposition: a retrospective observational cohort study

OBJECTIVES

Intracranial pressure (ICP) monitoring is recommended for severe traumatic brain injuries (TBI) but some data suggests it may not improve outcomes. The objective was to investigate the effect of ICP monitoring among TBI.

METHODS

This retrospective observational cohort study (1/1/2015-6/1/2020) included severe TBI patients. Outcomes [discharge destination, length of stay (LOS)] were compared by ICP monitoring and were stratified by GCS (3 vs. 4-8), α < 0.05.

RESULTS

Of the123 patients who met inclusion criteria, 47% received ICP monitoring. There were baseline differences in the two groups characteristics, ICP monitored patients were younger (p = 0.02), had a subarachnoid hemorrhage less often (p = 0.04), and a subdural hematoma more often (p = 0.04) than those without ICP monitors. ICP monitored patients had a significantly longer median LOS (12 vs. 3, p < 0.01) than patients without monitoring. There was a trend towards more ICP monitored patients discharged home (40% vs. 23%, p = 0.06). Among patients with GCS = 3, ICP monitored patients had a longer LOS (p < 0.01) with no significant differences in discharge destinations. For those with a GCS of 4-8, ICP monitoring was associated with a longer LOS (p = 0.01), but fewer were discharged to a skilled nursing facility or long-term care (p = 0.01).

CONCLUSIONS

For TBI patients, ICP monitoring was associated with an increased LOS, with no significant differences in discharge destinations when compared to those without ICP monitoring. However, among only those with a GCS of 4-8, ICP monitoring was associated with a decreased proportion of patients discharged to a skilled nursing facility or long-term acute care .

Traumatic Brain Injury in Different Age Groups

Traumatic Brain Injury (TBI) is a global health burden [...].

Traumatic brain injury: progress and challenges in prevention, clinical care, and research

Traumatic brain injury (TBI) has the highest incidence of all common neurological disorders, and poses a substantial public health burden. TBI is increasingly documented not only as an acute condition but also as a chronic disease with long-term consequences, including an increased risk of late-onset neurodegeneration. The first Lancet Neurology Commission on TBI, published in 2017, called for a concerted effort to tackle the global health problem posed by TBI. Since then, funding agencies have supported research both in high-income countries (HICs) and in low-income and middle-income countries (LMICs). In November 2020, the World Health Assembly, the decision-making body of WHO, passed resolution WHA73.10 for global actions on epilepsy and other neurological disorders, and WHO launched the Decade for Action on Road Safety plan in 2021. New knowledge has been generated by large observational studies, including those conducted under the umbrella of the International Traumatic Brain Injury Research (InTBIR) initiative, established as a collaboration of funding agencies in 2011. InTBIR has also provided a huge stimulus to collaborative research in TBI and has facilitated participation of global partners. The return on investment has been high, but many needs of patients with TBI remain unaddressed. This update to the 2017 Commission presents advances and discusses persisting and new challenges in prevention, clinical care, and research.

In LMICs, the occurrence of TBI is driven by road traffic incidents, often involving vulnerable road users such as motorcyclists and pedestrians. In HICs, most TBI is caused by falls, particularly in older people (aged ≥65 years), who often have comorbidities. Risk factors such as frailty and alcohol misuse provide opportunities for targeted prevention actions. Little evidence exists to inform treatment of older patients, who have been commonly excluded from past clinical trials—consequently, appropriate evidence is urgently required. Although increasing age is associated with worse outcomes from TBI, age should not dictate limitations in therapy. However, patients injured by low-energy falls (who are mostly older people) are about 50% less likely to receive critical care or emergency interventions, compared with those injured by high-energy mechanisms, such as road traffic incidents.

Mild TBI, defined as a Glasgow Coma sum score of 13–15, comprises most of the TBI cases (over 90%) presenting to hospital. Around 50% of adult patients with mild TBI presenting to hospital do not recover to pre-TBI levels of health by 6 months after their injury. Fewer than 10% of patients discharged after presenting to an emergency department for TBI in Europe currently receive follow-up. Structured follow-up after mild TBI should be considered good practice, and urgent research is needed to identify which patients with mild TBI are at risk for incomplete recovery.

The selection of patients for CT is an important triage decision in mild TBI since it allows early identification of lesions that can trigger hospital admission or life-saving surgery. Current decision making for deciding on CT is inefficient, with 90–95% of scanned patients showing no intracranial injury but being subjected to radiation risks. InTBIR studies have shown that measurement of blood-based biomarkers adds value to previously proposed clinical decision rules, holding the potential to improve efficiency while reducing radiation exposure. Increased concentrations of biomarkers in the blood of patients with a normal presentation CT scan suggest structural brain damage, which is seen on MR scanning in up to 30% of patients with mild TBI. Advanced MRI, including diffusion tensor imaging and volumetric analyses, can identify additional injuries not detectable by visual inspection of standard clinical MR images. Thus, the absence of CT abnormalities does not exclude structural damage—an observation relevant to litigation procedures, to management of mild TBI, and when CT scans are insufficient to explain the severity of the clinical condition.

Although blood-based protein biomarkers have been shown to have important roles in the evaluation of TBI, most available assays are for research use only. To date, there is only one vendor of such assays with regulatory clearance in Europe and the USA with an indication to rule out the need for CT imaging for patients with suspected TBI. Regulatory clearance is provided for a combination of biomarkers, although evidence is accumulating that a single biomarker can perform as well as a combination. Additional biomarkers and more clinical-use platforms are on the horizon, but cross-platform harmonisation of results is needed. Health-care efficiency would benefit from diversity in providers.

In the intensive care setting, automated analysis of blood pressure and intracranial pressure with calculation of derived parameters can help individualise management of TBI. Interest in the identification of subgroups of patients who might benefit more from some specific therapeutic approaches than others represents a welcome shift towards precision medicine. Comparative-effectiveness research to identify best practice has delivered on expectations for providing evidence in support of best practices, both in adult and paediatric patients with TBI.

Progress has also been made in improving outcome assessment after TBI. Key instruments have been translated into up to 20 languages and linguistically validated, and are now internationally available for clinical and research use. TBI affects multiple domains of functioning, and outcomes are affected by personal characteristics and life-course events, consistent with a multifactorial bio-psycho-socio-ecological model of TBI, as presented in the US National Academies of Sciences, Engineering, and Medicine (NASEM) 2022 report. Multidimensional assessment is desirable and might be best based on measurement of global functional impairment. More work is required to develop and implement recommendations for multidimensional assessment. Prediction of outcome is relevant to patients and their families, and can facilitate the benchmarking of quality of care. InTBIR studies have identified new building blocks (eg, blood biomarkers and quantitative CT analysis) to refine existing prognostic models. Further improvement in prognostication could come from MRI, genetics, and the integration of dynamic changes in patient status after presentation.

Neurotrauma researchers traditionally seek translation of their research findings through publications, clinical guidelines, and industry collaborations. However, to effectively impact clinical care and outcome, interactions are also needed with research funders, regulators, and policy makers, and partnership with patient organisations. Such interactions are increasingly taking place, with exemplars including interactions with the All Party Parliamentary Group on Acquired Brain Injury in the UK, the production of the NASEM report in the USA, and interactions with the US Food and Drug Administration. More interactions should be encouraged, and future discussions with regulators should include debates around consent from patients with acute mental incapacity and data sharing. Data sharing is strongly advocated by funding agencies. From January 2023, the US National Institutes of Health will require upload of research data into public repositories, but the EU requires data controllers to safeguard data security and privacy regulation. The tension between open data-sharing and adherence to privacy regulation could be resolved by cross-dataset analyses on federated platforms, with the data remaining at their original safe location. Tools already exist for conventional statistical analyses on federated platforms, however federated machine learning requires further development. Support for further development of federated platforms, and neuroinformatics more generally, should be a priority.

This update to the 2017 Commission presents new insights and challenges across a range of topics around TBI: epidemiology and prevention (section 1 ); system of care (section 2 ); clinical management (section 3 ); characterisation of TBI (section 4 ); outcome assessment (section 5 ); prognosis (Section 6 ); and new directions for acquiring and implementing evidence (section 7 ). Table 1 summarises key messages from this Commission and proposes recommendations for the way forward to advance research and clinical management of TBI.

The Next Frontier in Neurocritical Care in Resource-Constrained Settings

Neurocritical care (NCC) is an emerging field within critical care medicine, reflecting the widespread prevalence of neurologic injury in critically ill patients. Morbidity and mortality from neurocritical illness (NCI) have been reduced substantially in resource-rich settings (RRS), owing to the development of advanced technologies, neuro-specific units, and subspecialized medical training. Despite shouldering much of the burden of NCI worldwide, resource-limited settings (RLS) face immense hurdles when implementing guidelines generated in RRS. This review summarizes the current epidemiology, management, and outcomes of the most common NCIs in RLS and offers commentary on future directions in NCC practiced in RLS.

Prediction of Intracranial Hypertension and Brain Tissue Hypoxia Utilizing High-Resolution Data from the BOOST-II Clinical Trial

The current approach to intracranial hypertension and brain tissue hypoxia is reactive, based on fixed thresholds. We used statistical machine learning on high-frequency intracranial pressure (ICP) and partial brain tissue oxygen tension (PbtO₂) data obtained from the BOOST-II trial with the goal of constructing robust quantitative models to predict ICP/PbtO₂ crises. We derived the following machine learning models: logistic regression (LR), elastic net, and random forest. We split the data set into 70–30% for training and testing and utilized a discrete-time survival analysis framework and 5-fold hyperparameter optimization strategy for all models. We compared model performances on discrimination between events and non-events of increased ICP or low PbtO₂ with the area under the receiver operating characteristic (AUROC) curve. We further analyzed clinical utility through a decision curve analysis (DCA). When considering discrimination, the number of features, and interpretability, we identified the RF model that combined the most recent ICP reading, episode number, and longitudinal trends over the preceding 30 min as the best performing for predicting ICP crisis events within the next 30 min (AUC 0.78). For PbtO₂, the LR model utilizing the most recent reading, episode number, and longitudinal trends over the preceding 30 min was the best performing (AUC, 0.84). The DCA showed clinical usefulness for wide risk of thresholds for both ICP and PbtO₂ predictions. Acceptable alerting thresholds could range from 20% to 80% depending on a patient-specific assessment of the benefit-risk ratio of a given intervention in response to the alert.

The Impact of Invasive Brain Oxygen Pressure Guided Therapy on the Outcome of Patients with Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Traumatic brain injury (TBI) is a major public health burden, causing death and disability worldwide. Intracranial hypertension and brain hypoxia are the main mechanisms of secondary brain injury. As such, management strategies guided by intracranial pressure (ICP) and brain oxygen (PbtO₂) monitoring could improve the prognosis of these patients. Our objective was to summarize the current evidence regarding the impact of PbtO₂-guided therapy on the outcome of patients with TBI. We performed a systematic search of PubMed, Scopus, and the Cochrane library databases, following the protocol registered in PROSPERO. Only studies comparing PbtO₂/ICP-guided therapy with ICP-guided therapy were selected. Primary outcome was neurological outcome at 3 and 6 months assessed by using the Glasgow Outcome Scale; secondary outcomes included hospital and long-term mortality, burden of intracranial hypertension, and brain tissue hypoxia. Out of 6254 retrieved studies, 15 studies (n = 37,245 patients, of who 2184 received PbtO₂-guided therapy) were included in the final analysis. When compared with ICP-guided therapy, the use of combined PbO₂/ICP-guided therapy was associated with a higher probability of favorable neurological outcome (odds ratio 2.21 [95% confidence interval 1.72-2.84]) and of hospital survival (odds ratio 1.15 [95% confidence interval 1.04-1.28]). The heterogeneity (I²) of the studies in each analysis was below 40%. However, the quality of evidence was overall low to moderate. In this meta-analysis, PbtO₂-guided therapy was associated with reduced mortality and more favorable neurological outcome in patients with TBI. The low-quality evidence underlines the need for the results from ongoing phase III randomized trials.

Decision Support Tool to Judiciously Assign High-Frequency Neurologic Examinations in Traumatic Brain Injury

INTRODUCTION

Traumatic brain injury (TBI) management includes serial neurologic examinations to assess for changes dictating neurosurgical interventions. We hypothesized hourly examinations are overassigned. We conducted a decision tree analysis to determine an algorithm to judiciously assign hourly examinations.

METHODS

A retrospective cohort study of 1022 patients with TBI admitted to a Level 1 trauma center from January 1, 2019, to December 31, 2019, was conducted. Patients with penetrating TBI or immediate or planned interventions and those with nonsurvivable injuries were excluded. Patients were stratified by whether they underwent an unplanned intervention (e.g., craniotomy or invasive intracranial monitoring). Univariate analysis identified factors for inclusion in chi-square automatic interaction detection technique, classifying those at risk for unplanned procedures.

RESULTS

A total of 830 patients were included, 287 (35%) were assigned hourly (Q1) examinations, and 17 (2%) had unplanned procedures, with 16 of 17 (94%) on Q1 examinations. Patients requiring unplanned procedures were more likely to have mixed intracranial hemorrhage pattern (82% versus 39%; P = 0.001), midline shift (35% versus 14%; P = 0.023), an initial poor neurologic examination (Glasgow Comas Scale ≤8, 77% versus 14%; P < 0.001), and be intubated (88% versus 17%; P < 0.001). Using chi-square automatic interaction detection, the decision tree demonstrated low-risk (2% misclassification) and excellent discrimination (area under the curve = 0.915, 95% confidence interval 0.844-0.986; P < 0.001) of patients at risk of an unplanned procedure. By following the algorithm, 167 fewer patients could have been assigned Q1 examinations, resulting in an estimated 6012 fewer examinations.

CONCLUSIONS

Using a 4-factor algorithm can optimize the assignment of neuro examinations and substantially reduce neuro examination burden without sacrificing patient safety.

Local cerebral blood flow assessment using transcranial Doppler ultrasonography in a dog with brain infarction in the right middle cerebral artery territory

A 12-year-old neutered male Chihuahua was diagnosed with acute brain infarction in the right middle cerebral artery (MCA) territory. Transcranial Doppler ultrasonography (TCD) was performed to assess the local cerebral blood flow at the time of diagnosis and after 4 and 31 hr. Initially, the right MCA retained blood flow but with a lower cerebral blood flow velocity (CBFV; 14.9 cm/sec) than the left MCA (27.9 cm/sec). The TCD vascular resistance variables were higher in the right than in the left MCA. An increase in the CBFV and a decrease in TCD vascular resistance variables were observed, consistent with improvements in neurological symptoms. TCD can be a non-invasive, and easy-to-use modality for bedside monitoring of cerebral edema and infarction.

Second- and Third-Tier Therapies for Severe Traumatic Brain Injury

Intracranial hypertension is a common finding in patients with severe traumatic brain injury. These patients need treatment in the intensive care unit, where intracranial pressure monitoring and, whenever possible, multimodal neuromonitoring can be applied. A three-tier approach is suggested in current recommendations, in which higher-tier therapies have more significant side effects. In this review, we explain the rationale for this approach, and analyze the benefits and risks of each therapeutic modality. Finally, we discuss, based on the most recent recommendations, how this approach can be adapted in low- and middle-income countries, where available resources are limited.

Clustering identifies endotypes of traumatic brain injury in an intensive care cohort: a CENTER-TBI study

BACKGROUND

While the Glasgow coma scale (GCS) is one of the strongest outcome predictors, the current classification of traumatic brain injury (TBI) as 'mild', 'moderate' or 'severe' based on this fails to capture enormous heterogeneity in pathophysiology and treatment response. We hypothesized that data-driven characterization of TBI could identify distinct endotypes and give mechanistic insights.

METHODS

We developed an unsupervised statistical clustering model based on a mixture of probabilistic graphs for presentation (< 24 h) demographic, clinical, physiological, laboratory and imaging data to identify subgroups of TBI patients admitted to the intensive care unit in the CENTER-TBI dataset (N = 1,728). A cluster similarity index was used for robust determination of optimal cluster number. Mutual information was used to quantify feature importance and for cluster interpretation.

RESULTS

Six stable endotypes were identified with distinct GCS and composite systemic metabolic stress profiles, distinguished by GCS, blood lactate, oxygen saturation, serum creatinine, glucose, base excess, pH, arterial partial pressure of carbon dioxide, and body temperature. Notably, a cluster with 'moderate' TBI (by traditional classification) and deranged metabolic profile, had a worse outcome than a cluster with 'severe' GCS and a normal metabolic profile. Addition of cluster labels significantly improved the prognostic precision of the IMPACT (International Mission for Prognosis and Analysis of Clinical trials in TBI) extended model, for prediction of both unfavourable outcome and mortality (both p < 0.001).

CONCLUSIONS

Six stable and clinically distinct TBI endotypes were identified by probabilistic unsupervised clustering. In addition to presenting neurology, a profile of biochemical derangement was found to be an important distinguishing feature that was both biologically plausible and associated with outcome. Our work motivates refining current TBI classifications with factors describing metabolic stress. Such data-driven clusters suggest TBI endotypes that merit investigation to identify bespoke treatment strategies to improve care. Trial registration The core study was registered with ClinicalTrials.gov, number NCT02210221 , registered on August 06, 2014, with Resource Identification Portal (RRID: SCR_015582).

Evaluation of decompressive craniectomy in mice after severe traumatic brain injury

Decompressive craniectomy (DC) is of great significance for relieving acute intracranial hypertension and saving lives after traumatic brain injury (TBI). In this study, a severe TBI mouse model was created using controlled cortical impact (CCI), and a surgical model of DC was established. Furthermore, a series of neurological function assessments were performed to better understand the pathophysiological changes after DC. In this study, mice were randomly allocated into three groups, namely, CCI group, CCI+DC group, and Sham group. The mice in the CCI and CCI+DC groups received CCI after opening a bone window, and after brain injury, immediately returned the bone window to simulate skull condition after a TBI. The CCI+DC group underwent DC and contused tissue removal 6 h after CCI. The mice in the CCI group underwent the same anesthesia process; however, no further treatment of the bone window and trauma was performed. The mice in the Sham group underwent anesthesia and the process of opening the skin and bone window, but not in the CCI group. Changes in Modified Neurological Severity Score, rotarod performance, Morris water maze, intracranial pressure (ICP), cerebral blood flow (CBF), brain edema, blood–brain barrier (BBB), inflammatory factors, neuronal apoptosis, and glial cell expression were evaluated. Compared with the CCI group, the CCI+DC group had significantly lower ICP, superior neurological and motor function at 24 h after injury, and less severe BBB damage after injury. Most inflammatory cytokine expressions and the number of apoptotic cells in the brain tissue of mice in the CCI+DC group were lower than in the CCI group at 3 days after injury, with markedly reduced astrocyte and microglia expression. However, the degree of brain edema in the CCI+DC group was greater than in the CCI group, and neurological and motor functions, as well as spatial cognitive and learning ability, were significantly poorer at 14 days after injury.

Providing Neurocritical Care in Resource-Limited Settings: Challenges and Opportunities

Acute neurologic illnesses (ANI) contribute significantly to the global burden of disease and cause disproportionate death and disability in low-income and middle-income countries (LMICs) where neurocritical care resources and expertise are limited. Shifting epidemiologic trends in recent decades have increased the worldwide burden of noncommunicable diseases, including cerebrovascular disease and traumatic brain injury, which coexist in many LMICs with a persistently high burden of central nervous system infections such as tuberculosis, neurocysticercosis, and HIV-related opportunistic infections and complications. In the face of this heavy disease burden, many resource-limited countries lack the infrastructure to provide adequate care for patients with ANI. Major gaps exist between wealthy and poor countries in access to essential resources such as intensive care unit beds, neuroimaging, clinical laboratories, neurosurgical capacity, and medications for managing complex neurologic emergencies. Moreover, many resource-limited countries face critical shortages in health care workers trained to manage neurologic emergencies, with subspecialized neurocritical care expertise largely absent outside of high-income countries. Numerous opportunities exist to overcome these challenges through capacity-building efforts that improve outcomes for patients with ANI in resource-limited countries. These include research on needs and best practices for ANI management in LMICs, developing systems for effective triage, education and training to expand the neurology workforce, and supporting increased collaboration and data sharing among LMIC health care workers and systems. The success of these efforts in curbing the disproportionate and rising impact of ANI in LMICs will depend on the coordinated engagement of the global neurocritical care community.

The Application of Guideline-Based Care for Traumatic Brain and Spinal Cord Injury in Low- and Middle-Income Countries: A Provider-Based Survey

Objective

Neurosurgical guidelines have resulted in improved clinical outcomes and more optimized care for many complex neurosurgical pathologies. As momentum in global neurosurgical efforts has grown, there is little understanding about the application of these guidelines in low- and middle-income countries.

Methods

A 29-question survey was developed to assess the application of specific recommendations from neurosurgical brain and spinal cord injury guidelines. Surveys were distributed to an international cohort of neurosurgeons and neurotrauma stakeholders.

Results

A total of 82 of 222 (36.9%) neurotrauma providers responded to the survey. The majority of respondents practiced in low- and middle-income countries settings (49/82, 59.8%). There was a significantly greater mean traumatic brain injury volume in low-income countries (56% ± 13.5) and middle-income countries (46.5% ± 21.3) compared with high-income countries (27.9% ± 13.2), P < 0.001. Decompressive hemicraniectomy was estimated to occur in 61.5% (±30.8) of cases of medically refractory intracranial pressure with the lowest occurrence in the African region (44% ± 37.5). The use of prehospital cervical immobilization varied significantly by income status, with 36% (±35.6) of cases in low-income countries, 52.4% (±35.5) of cases in middle-income countries, and 95.2% (±10) in high-income countries, P < 0.001. Mean arterial pressure elevation greater than 85 mm Hg to improve spinal cord perfusion was estimated to occur in 71.7% of cases overall with lowest occurrence in Eastern Mediterranean region (55.6% ± 24).

Conclusions

While some disparities in guideline implementation are inevitably related to the availability of clinical resources, other differences could be more quickly improved with accessibility of current evidence-based guidelines and development of local data.

A proposed novel traumatic brain injury classification system - an overview and inter-rater reliability validation on behalf of the Society of British Neurological Surgeons

INTRODUCTION

The measurement of traumatic brain injury (TBI) 'severity' has traditionally been based on the earliest Glasgow Coma Score (GCS) recorded, however, the underlying parenchymal pathology is highly heterogonous. This heterogeneity renders prediction of outcome on an individual patient level inaccurate and makes comparison between patients both in clinical practice and research difficult. The complexity of this heterogeneity has resulted in generic all encompassing 'traumatic brain injury protocols'. Early management and studies of neuro-protectants are often done irrespective of TBI type, yet it may well be that a specific treatment may be beneficial in a subset of TBI pathologies.

METHODS

A simple CT-based classification system rating the recognised types of blunt TBI (extradural, subdural, subarachnoid haemorrhage, contusions/intracerebral haematoma and diffuse axonal injury) as mild (1), moderate (2) or severe (3) is proposed. Hypoxic brain injury, a common secondary injury following TBI, is also included. Scores can be combined to reflect concomitant types of TBI and predominant location of injury is also recorded. To assess interrater reliability, 50 patient CT images were assessed by 5 independent clinicians of varying experience. Interrater reliability was calculated using overall agreement through Cronbach's alpha including confidence intervals for intra-class coefficients.

RESULTS

Interrater reliability scores showed strong agreement for same score and same injury for TBIs with blood on CT and Cronbach's alpha co-efficient (range 0.87-0.93) demonstrated excellent correlation between raters. Cronbach's alpha was not affected when individual raters were removed.

CONCLUSIONS

The proposed simple CT classification system has good inter-rater reliability and hence potentially could enable better individual prognostication and targeted treatments to be compared while also accounting for multiple intracranial injury types. Further studies are proposed and underway.

Arterial catheterization and in-hospital mortality in sepsis: a propensity score-matched study

Background

Despite the extensive use of arterial catheterization (AC), clinical effectiveness of AC to alter the outcomes among patients with sepsis and septic shock has not been evaluated. The purpose of this study is to examine the association between the use of AC and in-hospital mortality in septic patients.

Methods

Adult patients with sepsis from Medical Information Mart for Intensive Care database were screened to conduct this retrospective observational study. Propensity score matching (PSM) was employed to estimate the relationship between arterial catheterization (AC) and in-hospital mortality. Multivariable logistic regression and inverse probability of treatment weighing (IPTW) were used to validate our findings.

Results

A total of 14,509 septic patients without shock and 4,078 septic shock patients were identified. 3,489 pairs in sepsis patients without shock and 589 pairs in septic shock patients were yielded respectively after PSM. For patients in the sepsis without shock group, AC placement was associated with increased in-hospital mortality (OR, 1.34; 95% CI, 1.17–1.54; p < 0.001). In the septic shock group, there was no significant difference in hospital mortality between AC group and non-AC group. The results of logistic regression and propensity score IPTW model support our findings.

Conclusions

In hemodynamically stable septic patients, AC is independently associated with higher in-hospital mortality, while in patients with septic shock, AC was not associated with improvements in hospital mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01722-5.

Traumatic brain injury in the new millennium: new population and new management

INTRODUCTION

Traumatic brain injury (TBI) is one of the leading causes of death and disability globally. We present a study describing epidemiological changes in severe TBI and the impact these changes have had on management and analysing alternatives that may improve outcomes in this new population.

MATERIALS AND METHODS

We performed a retrospective, descriptive, cross-sectional analysis of patients presenting severe TBI at our hospital in the period of 1992-1996 and 2009-2013. We analysed demographic data, including age, sex, mortality, aetiology, anticoagulation, treatment, and functional outcome.

RESULTS

We reviewed data from 220 patients. In the second cohort, there were 40% fewer patients, mean age was 12 years older, patients were more frequently receiving anticoagulation therapy, and the percentage of interventions was halved. Aetiology varied, with traffic accidents being the main cause in the first group, and accidental falls and being hit by cars in the second group. There were no intergroup differences for mortality or functional outcomes.

CONCLUSION

The age of patients admitted due to severe TBI has increased. As a result of this, the main cause of severe TBI in our population is accidental falls in elderly, anticoagulated patients. Despite the low-energy nature of trauma, patients in the second cohort presented a poorer baseline status, and were less frequently eligible for surgery, with no improvement in mortality or functional outcomes.

Traumatic brain injury in the new millennium: A new population and new management

INTRODUCTION

Traumatic brain injury (TBI) is one of the leading causes of death and disability globally. We present a study describing epidemiological changes in severe TBI and the impact these changes have had on management and analysing alternatives that may improve outcomes in this new population.

MATERIALS AND METHODS

We performed a retrospective, descriptive, cross-sectional analysis of patients presenting severe TBI at our hospital in the period of 1992-1996 and 2009-2013. We analysed demographic data, including age, sex, mortality, aetiology, anticoagulation, treatment, and functional outcome.

RESULTS

We reviewed data from 220 patients. In the second cohort, there were 40% fewer patients, mean age was 12years older, patients were more frequently receiving anticoagulation therapy, and the percentage of interventions was halved. Aetiology varied, with traffic accidents being the main cause in the first group, and accidental falls and being hit by cars in the second group. There were no intergroup differences for mortality or functional outcomes.

CONCLUSION

The age of patients admitted due to severe TBI has increased. As a result of this, the main cause of severe TBI in our population is accidental falls in elderly, anticoagulated patients. Despite the low-energy nature of trauma, patients in the second cohort presented a poorer baseline status, and were less frequently eligible for surgery, with no improvement in mortality or functional outcomes.

Group-based trajectory modeling of intracranial pressure in patients with acute brain injury: Results from multi-center ICUs, 2008-2019

Objective

The objective of the study was to characterize the longitudinal, dynamic intracranial pressure (ICP) trajectory in acute brain injury (ABI) patients admitted to intensive care unit (ICU) and explore whether it added sights over traditional thresholds in predicting outcomes.

Methods

ABI patients with ICP monitoring were identified from two public databases named Medical Information Mart for the Intensive Care (MIMIC)‐IV and eICU Collaborative Research Database (eICU‐CRD). Group‐based trajectory modeling (GBTM) was employed to identify 4‐h ICP trajectories in days 0–5 post‐ICU admission. Then, logistic regression was used to compare clinical outcomes across distinct groups. To further validate previously reported thresholds, we created the receiver operating characteristic (ROC) curve in our dataset.

Results

A total of 810 eligible patients were ultimately enrolled in the study. GBTM analyses generated 6 distinct ICP trajectories, differing in the initial ICP, evolution pattern, and number/proportion of spikes >20/22 mmHg. Compared with patients in “the highest, declined then rose” trajectory, those belonging to the “lowest, stable,” “low, stable,” and “medium, stable” ICP trajectories were at lower risks of 30‐day mortality (odds ratio [OR] 0.04; 95% confidence interval [CI] 0.01, 0.21), (OR 0.04; 95% CI 0.01, 0.19), (OR 0.08; 95% CI 0.01, 0.42), respectively. ROC analysis demonstrated an unfavorable result, for example, 30‐day mortality in total cohort: an area under the curve (AUC): 0.528, sensitivity: 0.11, and specificity: 0.94.

Conclusions

This study identified three ICP trajectories associated with elevated risk, three with reduced risks for mortality during ICU hospitalization. Notably, a fixed ICP threshold should not be applied to all kinds of patients. GBTM, a granular method for describing ICP evolution and their association with clinical outcomes, may add to the current knowledge in intracranial hypertension treatment.

Treatment Trends and Inpatient Mortality in Isolated Severe Traumatic Brain Injury Using the National Trauma Data Bank

OBJECTIVE

Severe traumatic brain injury remains a leading cause of morbidity and mortality. Despite recommendations from the Brain Trauma Foundation, there is wide variability in treatment paradigms for severe TBI. We aim to elucidate the variability of treatment, particularly neurosurgical procedures and how it affects mortality.

METHODS

Adult Patients (<65 years) with a severe isolated TBI who were treated at an ACS Level 1 trauma center were identified in the National Trauma Database for the years 2007 through 2016. ICD-9 procedure codes were used to identify primary treatment approaches: intracranial pressure monitoring and cranial surgery (craniotomy/craniectomy).

RESULTS

Among the 25,327 patients with severe isolated traumatic brain injury, 14.0% and 18.0% of total patients underwent intracranial pressure monitoring or cranial surgery, respectively. Intracranial pressure monitoring reduced the odds of mortality, OR 0.89 (0.81, 0.98), but not to the extent of cranial surgery, OR 0.71 (0.65, 0.77).

CONCLUSION

BTF guidelines recommend placement of intracranial pressure monitor for severe TBI, however only 14 % of patients with isolated, severe TBI underwent intracranial pressure monitoring from 2007 to 2016. Intracranial pressure monitoring and cranial surgery decreases the odds of inpatient mortality in patients with severe TBI.