Management of moderate to severe traumatic brain injury: an update for the intensivist

Early intervention with pericyte Fli-1 post-TBI attenuates hippocampal BBB disruption and subsequent neuroinflammation with neurological deficits

The ETS transcription factor Fli-1, known for regulating the vitality of pericyte in mice, has not been thoroughly investigated in traumatic brain injury (TBI). In this study, we used a mouse TBI model to demonstrate that Fli-1 expression in pericyte within the ipsilateral hippocampus is significantly increased following TBI and is associated with pericyte loss. Interfering with Fli-1 expression in pericyte disrupted their interactions with microglia, which in turn inhibited the transformation of microglia to a pro-inflammatory phenotype. Administration of Fli-1 siRNA via lateral ventricle injection reduced pericyte loss, microglial activation, and neuroinflammation induced by TBI. Additionally, Fli-1 siRNA treatment reduced neurological damage in the hippocampus and improved memory and cognitive function. Overall, our findings suggest that Fli-1 expression in pericyte is closely linked to pericyte apoptosis and pericyte-microglia interactions. Inhibiting Fli-1 could mitigate pericyte loss, neuroinflammation, blood-brain barrier disruption, and cognitive decline, indicating that targeting Fli-1 may be a viable clinical strategy for TBI intervention.

Traumatic brain injuries in civilian war victims in Afghanistan

BACKGROUND

Traumatic brain injuries (TBIs) are a common cause of morbidity and mortality in war zones. Currently, the vast majority of reports on war-related TBIs concern soldiers, and little is known about this condition in civilians.

METHODS

This is a retrospective observational study from the EMERGENCY NGO hospital for civilian war victims in Kabul, Afghanistan. Data were gathered for all adults and children with war-related TBIs admitted between June and November 2021. The study aims to describe the epidemiology and clinical patterns of patients with war-related TBIs in a non-military context.

RESULTS

Out of a total of 1469 hospital admissions during the study period, 130 (8.8%) were war-related TBIs. Among these, 90 (69.2%) involved a penetrating brain injury. More than one-third of the study population were children aged 14 or younger (36.1%), and the most frequent cause of war-related TBIs was shells (58.1%). The median time from injury to admission was 3 hours (from 30 min to 3 days), with only 19% of patients presenting in the 'golden hour'. Neurosurgery was performed on 38 patients (29.2%), and 55 patients (42.3%) underwent mechanical ventilation. In-hospital mortality occurred in 35 patients (26.9%), including 15 do-not-resuscitate cases.

CONCLUSIONS

War-related TBIs were frequent among adults and children and had a high mortality rate. With more than one-third of patients undergoing mechanical ventilation, our data highlight that the availability of intensive care units with the ability to ventilate patients is of the utmost importance to save lives of civilians in areas of armed conflict.

Decision-making in interhospital transfer of traumatic brain injury patients: exploring the perspectives of surgeons at general hospitals and neurosurgeons at neurotrauma centres

BACKGROUND

Traumatic brain injury (TBI) is a significant public health concern. Advancing age and comorbidities are associated with a reduced probability of being transferred to neurotrauma centres (NTCs) from non-neurosurgical acute care trauma hospitals (ACTHs). However, the extent to which these decisions reflect well-considered treatment-limiting decisions and which influence other factors have on the decision-making process remains unclear.

OBJECTIVE

To increase the understanding of adults' access to NTC care by exploring the decision-making process for interhospital transfer of patients with isolated TBI, elucidating factors influencing these decisions.

METHODS

Fifteen surgeons and neurosurgeons from four hospitals in Norway were recruited through purposive sampling to four semi-structured focus group interviews. Surgeons represented ACTHs and neurosurgeons NTCs, and all participants were responsible for TBI patients' initial care and transfer decisions. Interviews were thematically analysed.

RESULTS

We identified several factors influencing transfer decisions, captured in six main themes under one overarching theme; 'The chance of a favourable outcome'. The six main themes reflect surgeons' and neurosurgeons' decision-making process, which included clinical and system-level factors: (A) 'Establish TBI severity: Glasgow Coma Scale score and head CT', (B) 'Preinjury health status: comorbidity, functioning, and age', (C) 'Distance from ACTH to NTC: distance is time and time is brain', (D) 'Uncertainty and insecurity', (E) 'Capacity at NTC', and (F) 'Next of kin involvement'.

CONCLUSION

On-call surgeons and neurosurgeons responsible for making transfer decisions for TBI patients emphasise the importance of patient-centred decisions, including individual patients' risk factors and overall health status.

Counteracting immunodepression by extracellular matrix hydrogel to promote brain tissue remodeling and neurological function recovery after traumatic brain injury

Traumatic brain injury (TBI), an intractable disorder of the central nervous system (CNS), is a leading cause of long-term disability and mortality in humans worldwide. However, there is still no effective therapy for TBI, and an important reason for this is TBI-induced immunodepression, which renders TBI patients with low resistance to infections and aggravated brain damage. In this study, a multifunctional extracellular matrix hydrogel was constructed for the treatment of TBI in terms of both counteracting the immunodepression and enhancing neurogenesis. The stromal cell-derived factor-1α (SDF-1α)-loaded hyaluronic acid (HA)/decellularized brain extracellular matrix (BM) hydrogel (SDF@HA/BM) not only mimicked the composition and the biological cues of brain extracellular matrix, but also exhibited the injectability, self-healing, and mechanical properties close to those of brain tissue. The SDF@HA/BM hydrogel protected activated immune cells from dysfunction during the acute phase of TBI for normal levels of inflammatory cytokines, thereby creating a favorable immune microenvironment for subsequent neurogenesis. The SDF-1α and the BM synergistically promoted neurogenesis after TBI by recruiting endogenous neural stem/progenitor cells and inducing their differentiation into neurons. In vivo results demonstrated that the SDF@HA/BM hydrogel exhibited desirable therapeutic effects in severe TBI mice through facilitating brain tissue remodeling and neurological function recovery, including limb balance, autonomous locomotion, and spatial learning and memory abilities, and relieving depression and anxiety. Our work provides a novel strategy for TBI treatment in terms of restoring immune homeostasis and enhancing neurogenesis using advanced biomaterials.

Biomechanical perspectives on traumatic brain injury in the elderly: a comprehensive review

Traumatic brain injuries (TBIs) pose a significant health concern among the elderly population, influenced by age-related physiological changes and the prevalence of neurodegenerative diseases. Understanding the biomechanical dimensions of TBIs in this demographic is vital for developing effective preventive strategies and optimizing clinical management. This comprehensive review explores the intricate biomechanics of TBIs in the elderly, integrating medical and aging studies, experimental biomechanics of head tissues, and numerical simulations. Research reveals that global brain atrophy in normal aging occurs at annual rates of -0.2% to -0.5%. In contrast, neurodegenerative diseases such as Alzheimer's, Parkinson's, and multiple sclerosis are associated with significantly higher rates of brain atrophy. These variations in atrophy rates underscore the importance of considering differing brain atrophy patterns when evaluating TBIs among the elderly. Experimental studies further demonstrate that age-related changes in the mechanical properties of critical head tissues increase vulnerability to head injuries. Numerical simulations provide insights into the biomechanical response of the aging brain to traumatic events, aiding in injury prediction and preventive strategy development tailored to the elderly. Biomechanical analysis is essential for understanding injury mechanisms and forms the basis for developing effective preventive strategies. By incorporating local atrophy and age-specific impact characteristics into biomechanical models, researchers can create targeted interventions to reduce the risk of head injuries in vulnerable populations. Future research should focus on refining these models and integrating clinical data to better predict outcomes and enhance preventive care. Advancements in this field promise to improve health outcomes and reduce injury risks for the aging population.

Dynamic pathophysiological features of early primary blast lung injury: a novel functional incapacity pig model

INTRODUCTION

While there is evidence supporting the use of ultrasound for real-time monitoring of primary blast lung injury (PBLI), uncertainties remain regarding the timely detection of early PBLI and the limited data correlating it with commonly used clinical parameters. Our objective is to develop a functional incapacity model for PBLI that better addresses practical needs and to verify the early diagnostic effectiveness of lung ultrasound in identifying PBLI.

METHODS

We selected six healthy male pigs to develop an animal model using a bio-shock tube (BST-I). The injuries were induced at a pressure of 4.8 MPa. We monitored the animals before and after the injury using various methods to detect changes in vital signs, lung function, and hemodynamics.

RESULTS

The experimental peak overpressure was measured at 405.89 ± 4.14KPa, with the duration of the first positive peak pressure being 50.01ms. The mortality rate six hours after injury was 50%. The average Military Combat Injury Scale was higher than 3. Significant increases were observed in heart rate (HR), shock index (SI), alveolar-arterial oxygen gradient (AaDO2), lung ultrasound scores(LUS), and pulmonary vascular permeability index (PVPI) at 0.5 h, 3 h, and 6 h after-injury (p < 0.05). Conversely, there were notable decreases in average arterial pressure(MAP), oxygenation index (OI), stroke volume per heartbeat(SV), cardiac output power index(CPI), global end-diastolic index (GEDI), and intrathoracic blood volume index (ITBI) during the same time periods (p < 0.05). Meanwhile, the extrapulmonary water index (ELWI) showed a significant increase at 0.5 h and 6 h after injury (p < 0.05). At 6 h after injury, pulmonary ultrasound scores were positively correlated with HR (R = 0.731, p < 0.001), AaDO2 (R = 0.612, p = 0.012), SI (R = 0.661, p = 0.004), ELWI (R = 0.811, p < 0.001), PVPI (R = 0.705, p = 0.002). In contrast, these scores were negatively correlated with SpO2 (R = -0.583, p = 0.007),OI (R = -0.772, p < 0.001), ITBI (R = -0.637, p = 0.006).

CONCLUSION

We have successfully developed a novel, and highly reproducible animal model for assessing serious PBLI functional incapacity. This model displays immediate symptoms of hypoxia, decreased cardiac output, decreased blood volume, and abnormal lung ultrasound findings within 0.5 h of injury, with syptoms lasting for up to 6 h. Lung ultrasound evaluation is crucial for the early assessment of injuries, and is comparable to commonly used clinical parameters.

Using Transorbital Sonography for Assessing Traumatic Brain Injury in Patients With Periorbital Hematoma

OBJECTIVE

The aim of this study is to assess the comparative effectiveness of transorbital sonography (TOS) and the pupillary penlight visual assessment method in patients with traumatic brain injury (TBI) and periorbital hematoma.

METHODS

A total of 140 patients with traumatic brain injury (TBI), meeting the inclusion and exclusion criteria, were selected from a tertiary hospital in Zhejiang Province between January 2022 and December 2023. Pupillary function in all patients was assessed using both TOS and the pupillary penlight visual assessment method on the first, third, and seventh day after admission. The stability and consistency of the measurement results were compared. Stability was determined using the coefficient of variation, whereas consistency was assessed using the intraclass correlation coefficient.

RESULTS

The coefficients of variation for the pupillary transverse diameter values measured by TOS were 29.84% (left) and 29.55% (right) on day 1, 27.81% (left) and 26.88% (right) on day 3, and 26.80% (left) and 25.51% (right) on day 7. These values were consistently lower than those obtained through the pupillary penlight visual assessment method, indicating superior stability with the TOS measurement. In addition, the intraclass correlation coefficient analysis demonstrated consistency between the 2 methods, with values ranging from 0.562 to 0.809 (P<0.05), indicating good consistency.

CONCLUSION

TOS represents an innovative tool for neurological assessment. It has been validated that the presence or absence of eyelid edema does not compromise the accuracy of ultrasound-based pupillary function measurements. The 2 methods of measurement exhibit good consistency, with the TOS method demonstrating superior stability in monitoring data. This approach provides a more accurate means of assessing pupillary function in patients with TBI who have periorbital hematoma or facial swelling, particularly when opening the eyelid is challenging, thereby addressing a significant clinical nursing challenge.

Disorders of Lymphatic Architecture and Flow in Critical Illness

OBJECTIVES

To provide a narrative review of disordered lymphatic dynamics and its impact on critical care relevant condition management.

DATA SOURCES

Detailed search strategy using PubMed and Ovid Medline for English language articles (2013-2023) describing congenital or acquired lymphatic abnormalities including lymphatic duct absence, injury, leak, or obstruction and their associated clinical conditions that might be managed by a critical care medicine practitioner.

STUDY SELECTION

Studies that specifically addressed abnormalities of lymphatic flow and their management were selected. The search strategy time frame was limited to the last 10 years to enhance relevance to current practice.

DATA EXTRACTION

Relevant descriptions or studies were reviewed, and abstracted data were parsed into structural or functional etiologies, congenital or acquired conditions, and their management within critical care spaces in an acute care facility.

DATA SYNTHESIS

Abnormal lymph flow may be identified stemming from congenital lymphatic anomalies including lymphatic structure absence as well as acquired obstruction or increased flow from clinical entities or acute therapy. Macro- and microsurgical as well as interventional radiological techniques may address excess, inadequate, or obstructed lymph flow. Patients with deranged lymph flow often require critical care, and those who require critical care may concomitantly demonstrate deranged lymph flow that adversely impacts care.

CONCLUSIONS

Critical care clinicians ideally demonstrate functional knowledge of conditions that are directly related to, or are accompanied by, deranged lymphatic dynamics to direct timely diagnostic and therapeutic interventions during a patient's ICU care episode.

An Overview of Adult Acute Traumatic Neurologic Injury for the Anesthesiologist: What is Known, What is New, and Emerging Concepts

Purpose of Review

We examine what is known, what is new, and what is emerging in acute neurotrauma relevant to the anesthesiologist.

Recent Findings

Timely and goal-directed care is critical for all patients requiring urgent/emergent anesthesia care. Anesthesia care for acute neurological injury should incorporate understanding the evolution of traumatic brain injury and spinal cord injury that translates to preoperative preparation, hemodynamic resuscitation, prevention of second insults, and safe transport between care settings. Anesthesia care should support optimizing patient outcomes.

Summary

Best practices involve extrapolating data from the intensive care unit setting since there is a lack of research addressing anesthesia care for acute neurological injury. There are opportunities to generate data to support evidence-based anesthetic care.

Association between cerebral oxygenation and usual parameters of cerebral perfusion in critically ill patients with acute brain injury

In patients with acute brain injury (ABI), optimizing cerebral perfusion parameters relies on multimodal monitoring. This include data from systemic monitoring-mean arterial pressure (MAP), arterial carbon dioxide tension (PaCO2), arterial oxygen saturation (SaO2), hemoglobin levels (Hb), and temperature-as well as neurological monitoring-intracranial pressure (ICP), cerebral perfusion pressure (CPP), and transcranial Doppler (TCD) velocities. We hypothesized that these parameters alone were not sufficient to assess the risk of cerebral ischemia. We conducted a retrospective, single-center study of patients admitted in our ICU between 2015 and 2021. Patients with ABI and multimodal neuromonitoring were included. ABI included traumatic brain injury (TBI), subarachnoid hemorrhage (SAH), intracranial hemorrhage and ischemic stroke. The relationship between jugular venous oxygen saturation (SjvO2) and cerebral perfusion parameters was analyzed. Patients were categorized into two groups based on SjvO2, with a threshold of 60% used to define cerebral ischemia. We compared the parameters used to optimize cerebral perfusion between groups and their diagnosis accuracy for cerebral ischemia was evaluated. Univariable and multivariable analyses were performed to assess the association between the guideline-recommended therapeutic targets and the risk of cerebral ischemia. 601 evaluations from 96 patients with simultaneous ICP, SjvO2 and TCD were analyzed. Poor relationships were found between SjvO2 and the parameters of cerebral perfusion. TCD flow velocities and PaCO2 were lower in the cerebral ischemia group while MAP, ICP and CPP were not different between groups. Most ischemic episodes occurred despite ICP < 22 mmHg and CPP ≥ 60 mmHg. For the diagnosis of cerebral ischemia, only TCD parameters and PaCO2 were associated with an area under the curve (AUC) > 0.5 but with a low accuracy. In multivariable analysis, the only guideline-recommended therapeutic target associated with a reduction of cerebral ischemia was a diastolic flow velocity (FV) > 20 cm.s-1.

High-quality targeted temperature management combined with decompressive craniectomy in patients with poor-grade aneurysmal subarachnoid hemorrhage: a secondary analysis of a multicenter prospective study

Background

The effect of targeted temperature management (TTM) combined with decompressive craniectomy (DC) on poor-grade aneurysmal subarachnoid hemorrhage (aSAH) has not been previously addressed in the literature. This study aims to investigate the therapeutic outcomes of the combination of TTM and DC in patients with poor-grade aSAH.

Methods

This study represents a secondary analysis of the Multicenter Clinical Research on Targeted Temperature Management of Poor-grade Aneurysmal Subarachnoid Hemorrhage (High-Quality TTM for PaSAH), a multicenter prospective study conducted in China. The High-Quality TTM for PaSAH study enrolled patients aged 18 years and older who were transported to the intensive care units (ICU) of three tertiary care hospitals in China between April 2022 and April 2024. Among these patients, those who underwent DC were included in the present analysis. Patients were divided into two groups: the DC-alone group and the TTM combined with the DC (TTM-DC) group. The DC-alone group maintained normothermia. The TTM-DC group used automated devices with a temperature feedback system (TFS). TTM was initiated with core temperatures between 36°C-37°C immediately after diagnosing poor-grade aSAH, and concurrent emergency aneurysm repair. This was followed by a rapid induction to 34°C-35°C, maintained for a minimum of 72 h. Subsequently, a slow rewarming process reached 36°C-37°C, which was maintained for at least 48 h. Primary outcomes were evaluated using the Modified Rankin Scale (mRS) score at 3 months. Secondary outcomes included the Glasgow Coma Scale (GCS) at discharge, ICU stay duration, length of hospitalization, proportion of external ventricular drainage (EVD), mechanical ventilation time, tracheostomy, midline shift, hydrocephalus, and delayed cerebral ischemia (DCI) on the 7th day. Safety outcomes comprised the incidence of pneumonia, myocardial infarction, stress hyperglycemia, thrombocytopenia, acute liver injury, hypokalemia, hypoproteinemia, and death at 90 days.

Results

Of the 141 patients enrolled in the High-Quality TTM for PaSAH study, 43 (25 in the TTM-DC group and 18 in the DC-alone group) were eligible for this secondary analysis. The TTM-DC group had a higher proportion of favorable outcomes (mRS 0-3: 56% vs. 22%, aOR 5.97, 95%CI 0.96-52.2, p = 0.071). After propensity score matching, the TTM combined with DC improved favorable outcome at 3 months (mRS 0-3: 61% vs. 22%, OR 5.50, 95%CI 1.36-26.3, p = 0.022). In addition, the TTM-DC group increased GCS score at discharge compared with the DC-alone group (9 vs. 3, β 2.58, 95%CI 0.32-4.84, p = 0.032). The incidence of safety outcomes was not increased in the TTM-DC group.

Conclusion

TTM combined with DC can improve clinical conditions at discharge and ameliorate short-term neurological outcomes in poor-grade aSAH patients. TTM should be considered one of the main treatments for poor-grade aSAH patients who underwent DC.

TILTomorrow today: dynamic factors predicting changes in intracranial pressure treatment intensity after traumatic brain injury

Practices for controlling intracranial pressure (ICP) in traumatic brain injury (TBI) patients admitted to the intensive care unit (ICU) vary considerably between centres. To help understand the rational basis for such variance in care, this study aims to identify the patient-level predictors of changes in ICP management. We extracted all heterogeneous data (2008 pre-ICU and ICU variables) collected from a prospective cohort (n = 844, 51 ICUs) of ICP-monitored TBI patients in the Collaborative European NeuroTrauma Effectiveness Research in TBI study. We developed the TILTomorrow modelling strategy, which leverages recurrent neural networks to map a token-embedded time series representation of all variables (including missing values) to an ordinal, dynamic prediction of the following day's five-category therapy intensity level (TIL(Basic)) score. With 20 repeats of fivefold cross-validation, we trained TILTomorrow on different variable sets and applied the TimeSHAP (temporal extension of SHapley Additive exPlanations) algorithm to estimate variable contributions towards predictions of next-day changes in TIL(Basic). Based on Somers' Dxy, the full range of variables explained 68% (95% CI 65-72%) of the ordinal variation in next-day changes in TIL(Basic) on day one and up to 51% (95% CI 45-56%) thereafter, when changes in TIL(Basic) became less frequent. Up to 81% (95% CI 78-85%) of this explanation could be derived from non-treatment variables (i.e., markers of pathophysiology and injury severity), but the prior trajectory of ICU management significantly improved prediction of future de-escalations in ICP-targeted treatment. Whilst there was no significant difference in the predictive discriminability (i.e., area under receiver operating characteristic curve) between next-day escalations (0.80 [95% CI 0.77-0.84]) and de-escalations (0.79 [95% CI 0.76-0.82]) in TIL(Basic) after day two, we found specific predictor effects to be more robust with de-escalations. The most important predictors of day-to-day changes in ICP management included preceding treatments, age, space-occupying lesions, ICP, metabolic derangements, and neurological function. Serial protein biomarkers were also important and may serve a useful role in the clinical armamentarium for assessing therapeutic needs. Approximately half of the ordinal variation in day-to-day changes in TIL(Basic) after day two remained unexplained, underscoring the significant contribution of unmeasured factors or clinicians' personal preferences in ICP treatment. At the same time, specific dynamic markers of pathophysiology associated strongly with changes in treatment intensity and, upon mechanistic investigation, may improve the timing and personalised targeting of future care.

Chronic glial activation and behavioral alterations induced by acute/subacute pioglitazone treatment in a mouse model of traumatic brain injury

Traumatic brain injury (TBI) is a disabling neurotraumatic condition and the leading cause of injury-related deaths and disability in the United States. Attenuation of neuroinflammation early after TBI is considered an important treatment target; however, while these inflammatory responses can induce secondary brain injury, they are also involved in the repair of the nervous system. Pioglitazone, which activates peroxisome proliferator-activated receptor gamma, has been shown to decrease inflammation acutely after TBI, but the long-term consequences of its use remain unknown. For this reason, the impacts of treatment with pioglitazone during the acute/subacute phase (30 min after injury and each subsequent 24 h for 5 days) after TBI were interrogated during the chronic phase (30- and 274-days post-injury (DPI)) in mice using the controlled cortical impact model of experimental TBI. Acute/subacute pioglitazone treatment after TBI results in long-term deleterious consequences, including disruption of tau homeostasis, chronic glial cell activation, neuronal pathology, and worsened injury severity particularly at 274 DPI, with male mice being more susceptible than female mice. Further, male pioglitazone-treated TBI mice exhibited increased dominant and offensive-like behavior while having a decreased non-social exploring behavior at 274 DPI. After TBI, both sexes exhibited glial activation at 30 DPI when treated with pioglitazone; however, while injury severity was increased in females it was not impacted in male mice. This work reveals that although pioglitazone has been shown to lead to attenuated TBI outcomes acutely, sex-based differences, timing and long-term consequences of treatment with glitazones must be considered and further studied prior to their clinical use for TBI therapy.

Prognostic role of quantitative pupillometry in traumatic brain injury: a scoping review

BACKGROUND

Traumatic brain injury (TBI) is a major cause of global mortality and disability, leading to primary and secondary brain injuries that can result in severe neurological, cognitive, and psychological impairments. Accurate and early prognosis of TBI outcomes is critical, particularly in assessing the risk of neurological decline, intracranial pressure (ICP) changes, and mortality.

OBJECTIVE

This systematic review aims to evaluate the prognostic value of quantitative pupillometry, particularly the Neurological Pupil Index (NPi), in predicting long-term outcomes in TBI patients.

METHODS

A systematic review was conducted following PRISMA guidelines, with the protocol registered on PROSPERO (CRD42023489079). Databases including PubMed, Scopus, and Embase were searched. Studies were included based on predefined inclusion criteria, focusing on the prognostic accuracy of automated pupillometry in TBI patients. Risk of bias was assessed using the Joanna Briggs Institute (JBI) tool, and evidence quality was evaluated using the Best-Evidence Synthesis approach.

RESULTS

Thirteen studies met the inclusion criteria, with sample sizes ranging from 36 to 2258 participants. The studies demonstrated a consistent association between lower NPi values and increased mortality, poorer functional outcomes, elevated ICP, and the need for emergency interventions. Despite variability in study design and sample sizes, strong evidence supported the use of NPi as a reliable prognostic tool in TBI management.

CONCLUSION

Automated infrared pupillometry, particularly through NPi measurement, offers important prognostic value in TBI patients. Incorporating NPi into routine clinical practice could improve the accuracy of prognosis and enhance patient management. Future research should focus on standardizing measurement protocols and validating these findings in larger, more diverse cohorts.

Early Intravenous Beta-Blockade with Esmolol in Adults with Severe Traumatic Brain Injury: A Phase 2a Intervention Design Study

BACKGROUND

Targeted beta-blockade after severe traumatic brain injury may reduce secondary brain injury by attenuating the sympathoadrenal response. The potential role and optimal dosage for esmolol, a selective, short-acting, titratable beta-1 beta-blocker, as a safe, putative early therapy after major traumatic brain injury has not been assessed.

METHODS

We conducted a single-center, open-label dose-finding study using an adaptive model-based design. Adults (18 years or older) with severe traumatic brain injury and intracranial pressure monitoring received esmolol within 24 h of injury to reduce their heart rate by 15% from baseline of the preceding 4 h while ensuring cerebral perfusion pressure was maintained above 60 mm Hg. In cohorts of three, the starting dosage and dosage increments were escalated according to a prespecified plan in the absence of dose-limiting toxicity. Dose-limiting toxicity was defined as failure to maintain cerebral perfusion pressure, triggering cessation of esmolol infusion. The primary outcome was the maximum tolerated dosage schedule of esmolol, defined as that associated with less than 10% probability of dose-limiting toxicity. Secondary outcomes include 6-month mortality and 6-month extended Glasgow Outcome Scale score.

RESULTS

Sixteen patients (6 [37.5%] female patients; mean age 36 years [standard deviation 13 years]) with a median Glasgow Coma Scale score of 6.5 (interquartile range 5-7) received esmolol. The optimal starting dosage of esmolol was 10 μg/kg/min, with increments every 30 min of 5 μg/kg/min, as it was the highest dosage with less than 10% estimated probability of dose-limiting toxicity (7%). All-cause mortality was 12.5% at 6 months (corresponding to a standardized mortality ratio of 0.63). One dose-limiting toxicity event and no serious adverse hemodynamic effects were seen.

CONCLUSIONS

Esmolol administration, titrated to a heart rate reduction of 15%, is feasible within 24 h of severe traumatic brain injury. The probability of dose-limiting toxicity requiring withdrawal of esmolol when using the optimized schedule is low. Trial registrationI SRCTN, ISRCTN11038397, registered retrospectively January 7, 2021 ( https://www.isrctn.com/ISRCTN11038397 ).

Astrocyte-neuron crosstalk through extracellular vesicle-shuttled miRNA-382-5p promotes traumatic brain injury

Although astrocytes undergo functional changes in response to brain injury and may be the driving force of subsequent neuronal death, the underlying mechanisms remain incompletely elucidated. Here, we showed that extracellular vesicle (EV)-shuttled miRNA-382-5p may serve as a biomarker for the severity of traumatic brain injury (TBI), as the circulating EV-miRNA-382-5p level was significantly increased in both human patients and TBI model mice. Mechanistically, astrocyte-derived EVs delivered the shuttled miRNA-382-5p to mediate astrocyte-neuron communication, which promoted neuronal mitochondrial dysfunction by inhibiting the expression of optic atrophy-1 (OPA1). Consistent with these findings, genetic ablation of neuronal OPA1 exacerbated mitochondrial damage and neuronal apoptosis in response to TBI. Moreover, engineered RVG-miRNA-382-5p inhibitor-EVs, which can selectively deliver a miRNA-382-5p inhibitor to neurons, significantly attenuated mitochondrial damage and improved neurological function after TBI. Taken together, our data suggest that EV-shuttled miRNA-382-5p may be a critical mediator of astrocyte-induced neurotoxicity under pathological conditions and that targeting miRNA-382-5p-OPA1 signaling has potential for clinical translation in the treatment of traumatic brain injury.

Immune Response in Traumatic Brain Injury

PURPOSE OF REVIEW

This review aims to comprehensively examine the immune response following traumatic brain injury (TBI) and how its disruption can impact healing and recovery.

RECENT FINDINGS

The immune response is now considered a key element in the pathophysiology of TBI, with consequences far beyond the acute phase after injury. A delicate equilibrium is crucial for a healthy recovery. When this equilibrium is disrupted, chronic inflammation and immune imbalance can lead to detrimental effects on survival and disability. Globally, traumatic brain injury (TBI) imposes a substantial burden in terms of both years of life lost and years lived with disability. Although its epidemiology exhibits dynamic trends over time and across regions, TBI disproportionally affects the younger populations, posing psychosocial and financial challenge for communities and families. Following the initial trauma, the primary injury is succeeded by an inflammatory response, primarily orchestrated by the innate immune system. The inflammasome plays a pivotal role during this stage, catalyzing both programmed cell death pathways and the up-regulation of inflammatory cytokines and transcription factors. These events trigger the activation and differentiation of microglia, thereby intensifying the inflammatory response to a systemic level and facilitating the migration of immune cells and edema. This inflammatory response, initially originated in the brain, is monitored by our autonomic nervous system. Through the vagus nerve and adrenergic and cholinergic receptors in various peripheral lymphoid organs and immune cells, bidirectional communication and regulation between the immune and nervous systems is established.

PaCO2 Association with Outcomes of Patients with Traumatic Brain Injury at High Altitude: A Prospective Single-Center Cohort Study

BACKGROUND

Partial pressure of carbon dioxide (PaCO2) is generally known to influence outcome in patients with traumatic brain injury (TBI) at normal altitudes. Less is known about specific relationships of PaCO2 levels and clinical outcomes at high altitudes.

METHODS

This is a prospective single-center cohort of consecutive patients with TBI admitted to a trauma center located at 2600 m above sea level. An unfavorable outcome was defined as a Glasgow Outcome Scale-Extended (GOSE) score < 4 at the 6-month follow-up.

RESULTS

We had a total of 81 patients with complete data, 80% (65/81) were men, and the median (interquartile range) age was 36 (25-50) years. Median Glasgow Coma Scale (GCS) score on admission was 9 (6-14); 49% (40/81) of patients had severe TBI (GCS 3-8), 32% (26/81) had moderate TBI (GCS 12-9), and 18% (15/81) had mild TBI (GCS 13-15). The median (interquartile range) Abbreviated Injury Score of the head (AISh) was 3 (2-4). The frequency of an unfavorable outcome (GOSE < 4) was 30% (25/81), the median GOSE was 4 (2-5), and the median 6-month mortality rate was 24% (20/81). Comparison between patients with favorable and unfavorable outcomes revealed that those with unfavorable outcome were older, (median age 49 [30-72] vs. 29 [22-41] years, P < 0.01), had lower admission GCS scores (6 [4-8] vs. 13 [8-15], P < 0.01), had higher AISh scores (4 [4-4] vs. 3 [2-4], P < 0.01), had higher Acute Physiology and Chronic Health disease Classification System II scores (17 [15-23] vs. 10 [6-14], P < 0.01), had higher Charlson scores (0 [0-2] vs. 0 [0-0], P < 0.01), and had higher PaCO2 levels (mean 35 ± 8 vs. 32 ± 6 mm Hg, P < 0.01). In a multivariate analysis, age (odds ratio [OR] 1.14, 95% confidence interval [CI] 1.1-1.30, P < 0.01), AISh (OR 4.7, 95% CI 1.55-21.0, P < 0.05), and PaCO2 levels (OR 1.23, 95% CI 1.10-1.53, P < 0.05) were significantly associated with the unfavorable outcomes. When applying the same analysis to the subgroup on mechanical ventilation, AISh (OR 5.4, 95% CI 1.61-28.5, P = 0.017) and PaCO2 levels (OR 1.36, 95% CI 1.13-1.78, P = 0.015) remained significantly associated with the unfavorable outcome.

CONCLUSIONS

Higher PaCO2 levels are associated with an unfavorable outcome in ventilated patients with TBI. These results underscore the importance of PaCO2 levels in patients with TBI and whether it should be adjusted for populations living at higher altitudes.

The prognostic importance of traumatic axonal injury on early MRI: the Trondheim TAI-MRI grading and quantitative models

OBJECTIVES

We analysed magnetic resonance imaging (MRI) findings after traumatic brain injury (TBI) aiming to improve the grading of traumatic axonal injury (TAI) to better reflect the outcome.

METHODS

Four-hundred sixty-three patients (8-70 years) with mild (n = 158), moderate (n = 129), or severe (n = 176) TBI and early MRI were prospectively included. TAI presence, numbers, and volumes at predefined locations were registered on fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging, and presence and numbers on T2*GRE/SWI. Presence and volumes of contusions were registered on FLAIR. We assessed the outcome with the Glasgow Outcome Scale Extended. Multivariable logistic and elastic-net regression analyses were performed.

RESULTS

The presence of TAI differed between mild (6%), moderate (70%), and severe TBI (95%). In severe TBI, bilateral TAI in mesencephalon or thalami and bilateral TAI in pons predicted worse outcomes and were defined as the worst grades (4 and 5, respectively) in the Trondheim TAI-MRI grading. The Trondheim TAI-MRI grading performed better than the standard TAI grading in severe TBI (pseudo-R2 0.19 vs. 0.16). In moderate-severe TBI, quantitative models including both FLAIR volume of TAI and contusions performed best (pseudo-R2 0.19-0.21). In patients with mild TBI or Glasgow Coma Scale (GCS) score 13, models with the volume of contusions performed best (pseudo-R2 0.25-0.26).

CONCLUSIONS

We propose the Trondheim TAI-MRI grading (grades 1-5) with bilateral TAI in mesencephalon or thalami, and bilateral TAI in pons as the worst grades. The predictive value was highest for the quantitative models including FLAIR volume of TAI and contusions (GCS score <13) or FLAIR volume of contusions (GCS score ≥ 13), which emphasise artificial intelligence as a potentially important future tool.

CLINICAL RELEVANCE STATEMENT

The Trondheim TAI-MRI grading reflects patient outcomes better in severe TBI than today's standard TAI grading and can be implemented after external validation. The prognostic importance of volumetric models is promising for future use of artificial intelligence technologies.

KEY POINTS

Traumatic axonal injury (TAI) is an important injury type in all TBI severities. Studies demonstrating which MRI findings that can serve as future biomarkers are highly warranted. This study proposes the most optimal MRI models for predicting patient outcome at 6 months after TBI; one updated pragmatic model and a volumetric model. The Trondheim TAI-MRI grading, in severe TBI, reflects patient outcome better than today's standard grading of TAI and the prognostic importance of volumetric models in all severities of TBI is promising for future use of AI.

A profile of children with traumatic brain injury admitted to the paediatric intensive care unit of Red Cross War Memorial Children's Hospital in Cape Town, South Africa, between 2015 and 2019

Background

Paediatric traumatic brain injury (TBI) is a public health problem with high morbidity and mortality.

Objectives

To highlight risk factors and describe associated morbidity and mortality of children admitted with TBI to the Paediatric Intensive Care Unit (PICU) at Red Cross War Memorial Children's Hospital, Cape Town.

Methods

We retrospectively documented the hospitalisation of all children with TBI admitted into our PICU between 2015 and 2019.

Results

Of 320 children identified, 314 were enrolled: 267 (85%) had severe TBI (Glasgow Coma Scale (GCS) ≤8), 36 (11.5%) moderate TBI (GCS 9 - 12) and 11 (3.5%) mild TBI (GCS ≥13). Median age was 6.5 (interquartile range (IQR) 3.5 - 8.9) years; 194 (61.8%) were male. Motor vehicle collisions accounted for 75% (235) of injuries. Two hundred and seventy-nine (88.9%) children were invasively ventilated for a median of 4.5 (IQR 1 - 8) days; 13.9% (38/273) had a failed extubation and 10.8% (30/277) required tracheostomies. One hundred and sixty-three children (52.2%, n=312) had intracranial pressure monitoring. Almost a third (81/257) required vasopressor support. Approximately 40% (113/286) developed trauma-related seizures; 15.4% (44/286) required a thiopentone infusion and 6% (17/280) a decompressive craniectomy. Common complications were as follows: 12.2% developed post-extubation stridor (34/279), 10.5% a hemiparesis (33/314) and 6.4% diabetes insipidus (19/298). Median PICU stay was 4 (IQR 1 - 10) days, and hospitalisation 11 (IQR 5 - 21) days. Ninety-three (29.6%) children were transferred for further rehabilitation; 38 (12.1%) died.

Conclusion

Children admitted to our PICU with TBI had considerable morbidity and mortality, but this is a marked improvement since the 1990s. Enhanced primary preventive strategies, especially for motor vehicle collisions, are imperative to prevent TBI in children.

Contribution of the study

Paediatric traumatic brain injury (TBI) is associated with considerable morbidity and mortality. Through our profile of children with TBI admitted to PICU, we hope to contribute to future guidance and interventions to improve the quality of care in this subset of patients.

The impact of age and intensity of treatment on the outcome of traumatic brain injury

Background

Approximately one-third of trauma-related deaths are due to traumatic brain injury (TBI), particularly among young adults and elderly patients. Management strategies may vary across different age groups, potentially influencing short-term neurological outcomes. This study aims to investigate age-related disparities in treatment approaches and 3-month neurological outcomes among TBI patients.

Methods

We conducted a retrospective study on TBI patients requiring Intensive Care Unit (ICU) admission from January 1, 2015, to January 1, 2024, in a tertiary University hospital. Patient demographics, major comorbidities, ICU admission parameters, interventions and ICU complications were collected. An unfavorable neurological outcome at 3 months (UO) was defined as a Glasgow Outcome Scale (GOS) score of 1-3. A high therapy intensity level (TIL) was defined as a TIL basic of 3-4. A multivariable logistic regression model and a Cox proportional Hazard Regression model were used to assess the association of age and TIL with neurological outcome and mortality. A sensitivity analysis on low TIL (0-2) and high TIL subgroups was also conducted.

Results

We enrolled 604 TBI patients, of which 240 (40%) had UO. The highest prevalence of UO was found in patients aged ≥80 years (53/94, 56%), followed by patients aged 50-79 years (104/255, 41%). The age group 35-49 years had the lowest rate of UO (38/127, 30%). Older patients (age ≥ 80 years) received less frequently high TIL than others (p = 0.03). In the multivariable analysis, age ≥ 80 years [OR: 3.42 (95% CI 1.72-6.81)] was independently associated with UO, while age ≥ 80 years [HR 5.42 (95% CI 3.00-9.79)] and age 50-79 years [HR 2.03, (95% CI 1.19-3.48)] were independently associated with mortality. Although there was no interaction between age groups and TIL on outcome, an exploratory analysis showed that in the high TIL subgroup of patients, age had no independent impact on the outcome, whereas, in the low TIL group, age ≥ 80 years was independently associated with UO [OR: 3.65 (95% CI: 1.64-8.14)].

Conclusion

Older age, especially in the setting of low intensity treatment, may impact short-term neurological outcome of traumatic brain-injured patients.

Prophylactic Antibiotics in Adults With Acute Brain Injury Who Are Invasively Ventilated in the ICU: A Systematic Review and Meta-Analysis

BACKGROUND

Lower respiratory tract infections are common in patients receiving invasive mechanical ventilation in an ICU after an acute brain injury and may have deleterious consequences.

RESEARCH QUESTION

In adults with acute brain injury receiving invasive mechanical ventilation in an ICU, is the administration of prophylactic parenteral antibiotics, compared with placebo or usual care, associated with reduced mortality?

STUDY DESIGN AND METHODS

We conducted a systematic review and meta-analysis. We searched for randomized clinical trials (RCTs) in electronic databases, as well as unpublished trials. The primary outcome was hospital mortality, and secondary outcomes included the incidence of ventilator-associated pneumonia, ICU length of stay, and duration of mechanical ventilation. We used a random effects model to estimate the pooled risk ratio (RR) with corresponding 95% CI for binary outcomes and the mean difference (MD) with 95% CI for continuous outcomes. Certainty of evidence was evaluated using Grading of Recommendations Assessment Development and Evaluation methods.

RESULTS

One thousand seven hundred twenty-eight reports of studies were screened, with 7 RCTs recruiting 835 participants included. No trials were adjudicated as having a high risk of bias. The pooled estimated RR for mortality associated with the use of prophylactic antibiotics was 0.91 (95% CI, 0.70-1.17; P = .39; low certainty). The pooled estimated RR for ventilator-associated pneumonia was 0.56 (95% CI, 0.35-0.89; low certainty). The pooled estimated duration of mechanical ventilation for those allocated to prophylactic antibiotics compared with control participants (MD, -2.0 days; 95% CI, -6.1 to 2.1 days; very low certainty) and duration of ICU admission (MD, -2.2 days; 95% CI, -5.4 to 1.1 days; very low certainty) were similar.

INTERPRETATION

Current evidence from randomized clinical trials does not provide definitive evidence regarding the effect of prophylactic antibiotics on mortality in patients receiving invasive mechanical ventilation in the ICU.

CLINICAL TRIAL REGISTRY

International Prospective Register of Systematic Reviews; No.: CRD42023424732; URL: https://www.crd.york.ac.uk/prospero/.

Brain tissue oxygen pressure combined with intracranial pressure monitoring may improve clinical outcomes for patients with severe traumatic brain injury: a systemic review and meta-analysis

Background

Although the optimization of brain oxygenation is thought to improve the prognosis, the effect of brain tissue oxygen pressure (PbtO2) for patients with severe traumatic brain injury (STBI) remains controversial. Therefore, the present study aimed to determine whether adding PbtO2 to intracranial pressure (ICP) monitoring improves clinical outcomes for patients with STBI.

Methods

PubMed, Embase, Scopus and Cochrane Library were searched for eligible trials from their respective inception through April 10th, 2024. We included clinical trials contrasting the combined monitoring of PbtO2 and ICP versus isolated ICP monitoring among patients with STBI. The primary outcome was favorable neurological outcome at 6 months, and secondary outcomes including the in-hospital mortality, long-term mortality, length of stay in intensive care unit (ICU) and hospital.

Results

A total of 16 studies (four randomized studies and 12 cohort studies) were included in the meta-analysis. Compared with isolated ICP monitoring, the combined monitoring was associated with a higher favorable neurological outcome rate at 6 months (RR 1.33, 95% CI [1.17-1.51], P < 0.0001, I2 = 0%), reduced long-term mortality (RR 0.72, 95% CI [0.59-0.87], P = 0.0008, I2 = 2%). No significant difference was identified in the in-hospital mortality (RR 0.81, 95% CI 0.66 to 1.01, P = 0.06, I2 = 32%), length of stay in ICU (MD 2.10, 95% CI [-0.37-4.56], P = 0.10, I2 = 78%) and hospital (MD 1.07, 95% CI [-2.54-4.67], P = 0.56, I2 = 49%) between two groups. However, the pooled results of randomized studies did not show beneficial effect of combined monitoring in favorable neurological outcome and long-term mortality.

Conclusions

Currently, there is limited evidence to prove that the combined PbtO2 and ICP monitoring may contribute to improved neurological outcome and long-term mortality for patients with STBI. However, the benefit of combined monitoring should be further validated in more randomized studies.

Pulmonary Embolism in Critically Ill Patients-Prevention, Diagnosis, and Management

Critically ill patients in the intensive care unit (ICU) are often immobilized and on mechanical ventilation, placing them at increased risk for thromboembolic diseases, particularly deep vein thrombosis (DVT) and, to a lesser extent, pulmonary embolism (PE). While these conditions are frequently encountered in the emergency department, managing them in the ICU presents unique challenges. Although existing guidelines are comprehensive and effective, they are primarily designed for patients presenting with PE in the emergency department and do not fully address the complexities of managing critically ill patients in the ICU. This review aims to summarize the available data on these challenging cases, offering a practical approach to the prevention, diagnosis, and treatment of PE, particularly when it is acquired in the ICU.

Antiseizure Medications in Adult Patients With Traumatic Brain Injury: A Systematic Review and Bayesian Network Meta-Analysis

OBJECTIVES

We sought to evaluate the effectiveness of any antiseizure medication on the incidence of early post-traumatic seizures among adult patients with traumatic brain injury.

DATA SOURCES

MEDLINE, Embase, PubMed, Cochrane Central Register of Controlled Trials, and LILACS were searched from inception to October 2023.

STUDY SELECTION

We included randomized trials of adult patients with traumatic brain injury evaluating any antiseizure medication compared with either placebo or another agent.

DATA EXTRACTION

Two reviewers independently extracted individual study data and evaluated studies for risk of bias using the Cochrane Risk of Bias tool. Our main outcome of interest was the occurrence of early seizures (i.e., within 7 d); secondary outcomes included late-seizures and all-cause mortality.

DATA SYNTHESIS

Bayesian network meta-analyses were used to derive risk ratios (RRs) alongside 95% credible intervals (CrIs). We used Grading of Recommendations Assessment, Development, and Evaluation methodology to rate the certainty in our findings. Overall, ten individual randomized controlled trials (1851 participants) were included. Compared with placebo, phenytoin (RR, 0.28; 95% CrI, 0.13-0.57; moderate certainty) and levetiracetam (RR, 0.20; 95% CrI, 0.07-0.60; moderate certainty) were associated with a reduction in the risk of early seizures. Carbamazepine may be associated with a reduced risk of early seizures, but the evidence is very uncertain (RR, 0.41; 95% CrI, 0.12-1.27; very low certainty). Valproic acid may result in little to no difference in the risk of early seizures, but the evidence is very uncertain (RR, 0.97; 95% CrI, 0.16-9.00; very low certainty). The evidence is very uncertain about the impact of any antiseizure medication on the risk of late seizures or all-cause mortality at longest reported follow-up time.

CONCLUSIONS

Phenytoin or levetiracetam reduce the risk of early seizures among adult patients with traumatic brain injury. Further research is needed to evaluate required duration of therapy and long-term safety profiles.

How to Define and Meet Blood Pressure Targets After Traumatic Brain Injury: A Narrative Review

BACKGROUND

Traumatic brain injury (TBI) poses a significant challenge to healthcare providers, necessitating meticulous management of hemodynamic parameters to optimize patient outcomes. This article delves into the critical task of defining and meeting continuous arterial blood pressure (ABP) and cerebral perfusion pressure (CPP) targets in the context of severe TBI in neurocritical care settings.

METHODS

We narratively reviewed existing literature, clinical guidelines, and emerging technologies to propose a comprehensive approach that integrates real-time monitoring, individualized cerebral perfusion target setting, and dynamic interventions.

RESULTS

Our findings emphasize the need for personalized hemodynamic management, considering the heterogeneity of patients with TBI and the evolving nature of their condition. We describe the latest advancements in monitoring technologies, such as autoregulation-guided ABP/CPP treatment, which enable a more nuanced understanding of cerebral perfusion dynamics. By incorporating these tools into a proactive monitoring strategy, clinicians can tailor interventions to optimize ABP/CPP and mitigate secondary brain injury.

DISCUSSION

Challenges in this field include the lack of standardized protocols for interpreting multimodal neuromonitoring data, potential variability in clinical decision-making, understanding the role of cardiac output, and the need for specialized expertise and customized software to have individualized ABP/CPP targets regularly available. The patient outcome benefit of monitoring-guided ABP/CPP target definitions still needs to be proven in patients with TBI.

CONCLUSIONS

We recommend that the TBI community take proactive steps to translate the potential benefits of personalized ABP/CPP targets, which have been implemented in certain centers, into a standardized and clinically validated reality through randomized controlled trials.

Uncovering the protective potential of vanillic acid against traumatic brain injury-induced cognitive decline in male rats: Insights into underlying mechanisms

Traumatic brain injury (TBI) is a significant contributor to global mortality and disability, and there is still no specific drug available to treat cognitive deficits in survivors. Vanillic acid (VA), a bioactive phenolic compound, has shown protective effects in various models of neurodegeneration; however, its impact on TBI outcomes remains elusive. Therefore, this study aimed to elucidate the possible role of VA in ameliorating TBI-induced cognitive decline and to reveal the mechanisms involved. TBI was induced using the Marmarou impact acceleration model to deliver an impact force of 300 g, and treatment with VA (50 mg/kg; P.O.) was initiated 30 minutes post-TBI. The cognitive performance, hippocampal long-term potentiation (LTP), oxidative stress markers, neurological function, cerebral edema, and morphological changes were assessed at scheduled points in time. TBI resulted in cognitive decline in the passive avoidance task, impaired LTP in the perforant path-dentate gyrus (PP-DG) pathway, increased hippocampal oxidative stress, cerebral edema, neurological deficits, and neuronal loss in the rat hippocampus. In contrast, acute VA administration mitigated all the aforementioned TBI outcomes. The data suggest that reducing synaptic plasticity impairment, regulating oxidative and antioxidant defense, alleviating cerebral edema, and preventing neuronal loss by VA can be at least partially attributed to its protection against TBI-induced cognitive decline.

The Therapeutic Potential of Glucagon-like Peptide 1 Receptor Agonists in Traumatic Brain Injury

Traumatic brain injury (TBI), which is a global public health concern, can take various forms, from mild concussions to blast injuries, and each damage type has a particular mechanism of progression. However, TBI is a condition with complex pathophysiology and heterogenous clinical presentation, which makes it difficult to model for in vitro and in vivo studies and obtain relevant results that can easily be translated to the clinical setting. Accordingly, the pharmacological options for TBI management are still scarce. Since a wide spectrum of processes, such as glucose homeostasis, food intake, body temperature regulation, stress response, neuroprotection, and memory, were demonstrated to be modulated after delivering glucagon-like peptide 1 (GLP-1) or GLP-1 receptor agonists into the brain, we aimed to speculate on their potential role in TBI management by comprehensively overviewing the preclinical and clinical body of evidence. Based on promising preclinical data, GLP-1 receptor agonists hold the potential to extend beyond metabolic disorders and address unmet needs in neuroprotection and recovery after TBI, but also other types of central nervous system injuries such as the spinal cord injury or cerebral ischemia. This overview can lay the basis for tailoring new research hypotheses for future in vitro and in vivo models in TBI settings. However, large-scale clinical trials are crucial to confirm their safety and efficacy in these new therapeutic applications.

Albumin in Normovolemic Fluid Management for Severe Traumatic Brain Injury: Controversies and Research Gaps

Traumatic brain injury (TBI) is a significant public health issue characterized by high mortality rates and long-term complications. This commentary examines the controversial role of the use of albumin in the fluid management of patients with severe TBI. Despite its physiological benefits, the clinical use of albumin remains controversial due to the fact that various studies have yielded mixed results. Serum albumin is important for maintaining normovolemia, primarily through its contribution to colloid osmotic pressure, which helps to retain fluid in the circulatory system. This review highlights the existing evidence, examines inconsistencies in guideline recommendations, and suggests future research directions to clarify the efficacy and safety of the use of albumin in maintaining normovolemia in patients with TBI. The review also discusses the potential benefits of small-volume resuscitation strategies for the management of acute kidney injury in TBI patients, drawing parallels with the management of septic acute kidney injury. The need for further well-designed randomized controlled trials and ethical considerations in studies regarding the use of hyperoncotic albumin in TBI management is emphasized.

Mortality-Associated Factors in a Traumatic Brain Injury Population in Mexico

BACKGROUND

Traumatic brain injury (TBI) is a major cause of death and disability, with a rising incidence in recent years. Factors such as age, sex, hypotension, low score on the Glasgow Coma Scale, use of invasive mechanical ventilation and vasopressors, etc., have been associated with mortality caused by TBI. The aim of this study was to identify the clinical and sociodemographic characteristics that influence the mortality or survival of patients with TBI in a tertiary care hospital in Mexico.

METHODS

A sample of 94 patients aged 18 years or older, from both sexes, with an admitting diagnosis of mild-to-severe head trauma, with initial prehospital treatment, was taken. Data were extracted from the Single Registry of Patients with TBI at the Ixtapaluca Regional High Specialty Hospital (HRAEI). Normality tests were used to decide on the corresponding statistical analysis.

RESULTS

No factors associated with mortality were found; however, survival analysis showed that the presence of seizures, aggregate limb trauma, and subjects with diabetes mellitus, heart disease or patients with four concomitant comorbidities had 100% mortality. In addition, having seizures in the prehospital setting increased the risk of mortality four times. Although they did not have a direct association with mortality, they significantly decreased survival. A larger sample size is probably required to obtain an association with mortality.

CONCLUSIONS

These results reflect the severity of the clinical situation in this population and, although no risk factors were identified, they enlighten us about the conditions presented by patients who died.

A Machine Learning Model Based on CT Imaging Metrics and Clinical Features to Predict the Risk of Hospital-Acquired Pneumonia After Traumatic Brain Injury

Objective

To develop a validated machine learning (ML) algorithm for predicting the risk of hospital-acquired pneumonia (HAP) in patients with traumatic brain injury (TBI).

Materials and Methods

We employed the Least Absolute Shrinkage and Selection Operator (LASSO) to identify critical features related to pneumonia. Five ML models-Logistic Regression (LR), Extreme Gradient Boosting (XGB), Random Forest (RF), Naive Bayes Classifier (NB), and Support Vector Machine (SVC)-were developed and assessed using the training and validation datasets. The optimal model was selected based on its performance metrics and used to create a dynamic web-based nomogram.

Results

In a cohort of 858 TBI patients, the HAP incidence was 41.02%. LR was determined to be the optimal model with superior performance metrics including AUC, accuracy, and F1-score. Key predictive factors included Age, Glasgow Coma Score, Rotterdam Score, D-dimer, and the Systemic Immune Response to Inflammation Index (SIRI). The nomogram developed based on these predictors demonstrated high predictive accuracy, with AUCs of 0.818 and 0.819 for the training and validation datasets, respectively. Decision curve analysis (DCA) and calibration curves validated the model's clinical utility and accuracy.

Conclusion

We successfully developed and validated a high-performance ML algorithm to assess the risk of HAP in TBI patients. The dynamic nomogram provides a practical tool for real-time risk assessment, potentially improving clinical outcomes by aiding in early intervention and personalized patient management.

Performance of the ERC/ESICM-recommendations for neuroprognostication after cardiac arrest: Insights from a prospective multicenter cohort

AIM

To investigate the performance of the 2021 ERC/ESICM-recommended algorithm for predicting poor outcome after cardiac arrest (CA) and potential tools for predicting neurological recovery in patients with indeterminate outcome.

METHODS

Prospective, multicenter study on out-of-hospital CA survivors from 28 ICUs of the AfterROSC network. In patients comatose with a Glasgow Coma Scale motor score ≤3 at ≥72 h after resuscitation, we measured: (1) the accuracy of neurological examination, biomarkers (neuron-specific enolase, NSE), electrophysiology (EEG and SSEP) and neuroimaging (brain CT and MRI) for predicting poor outcome (modified Rankin scale score ≥4 at 90 days), and (2) the ability of low or decreasing NSE levels and benign EEG to predict good outcome in patients whose prognosis remained indeterminate.

RESULTS

Among 337 included patients, the ERC-ESICM algorithm predicted poor neurological outcome in 175 patients, and the positive predictive value for an unfavourable outcome was 100% [98-100]%. The specificity of individual predictors ranged from 90% for EEG to 100% for clinical examination and SSEP. Among the remaining 162 patients with indeterminate outcome, a combination of 2 favourable signs predicted good outcome with 99[96-100]% specificity and 23[11-38]% sensitivity.

CONCLUSION

All comatose resuscitated patients who fulfilled the ERC-ESICM criteria for poor outcome after CA had poor outcome at three months, even if a self-fulfilling prophecy cannot be completely excluded. In patients with indeterminate outcome (half of the population), favourable signs predicted neurological recovery, reducing prognostic uncertainty.

Artificial Intelligence-Enhanced Neurocritical Care for Traumatic Brain Injury : Past, Present and Future

In neurointensive care units (NICUs), particularly in cases involving traumatic brain injury (TBI), swift and accurate decision-making is critical because of rapidly changing patient conditions and the risk of secondary brain injury. The use of artificial intelligence (AI) in NICU can enhance clinical decision support and provide valuable assistance in these complex scenarios. This article aims to provide a comprehensive review of the current status and future prospects of AI utilization in the NICU, along with the challenges that must be overcome to realize this. Presently, the primary application of AI in NICU is outcome prediction through the analysis of preadmission and high-resolution data during admission. Recent applications include augmented neuromonitoring via signal quality control and real-time event prediction. In addition, AI can integrate data gathered from various measures and support minimally invasive neuromonitoring to increase patient safety. However, despite the recent surge in AI adoption within the NICU, the majority of AI applications have been limited to simple classification tasks, thus leaving the true potential of AI largely untapped. Emerging AI technologies, such as generalist medical AI and digital twins, harbor immense potential for enhancing advanced neurocritical care through broader AI applications. If challenges such as acquiring high-quality data and ethical issues are overcome, these new AI technologies can be clinically utilized in the actual NICU environment. Emphasizing the need for continuous research and development to maximize the potential of AI in the NICU, we anticipate that this will further enhance the efficiency and accuracy of TBI treatment within the NICU.

Using Physiological Biomarkers to Optimize Management of TBI in Austere Environments

INTRODUCTION

Multimodal monitoring is the use of data from multiple physiological sensors combined in a way to provide individualized patient management. It is becoming commonplace in the civilian care of traumatic brain-injured patients. We hypothesized we could bring the technology to the battlefield using a noninvasive sensor suite and an artificial intelligence-based patient management guidance system.

METHODS

Working with military medical personnel, we gathered requirements for a hand-held system that would adapt to the rapidly evolving field of neurocritical care. To select the optimal sensors, we developed a method to evaluate both the value of the sensor's measurement in managing brain injury and the burden to deploy that sensor in the battlefield. We called this the Value-Burden Analysis which resulted in a score weighted by the Role of Care. The Value was assessed using 7 criteria, 1 of which was the clinical value as assessed by a consensus of clinicians. The Burden was assessed using 16 factors such as size, weight, and ease of use. We evaluated and scored 17 sensors to test the assessment methodology. In addition, we developed a design for the guidance system, built a prototype, and tested the feasibility.

RESULTS

The resulting architecture of the system was modular, requiring the development of an interoperable description of each component including sensors, guideline steps, medications, analytics, resources, and the context of care. A Knowledge Base was created to describe the interactions of the modules. A prototype test set-up demonstrated the feasibility of the system in that simulated physiological inputs would mimic the guidance provided by the current Clinical Practice Guidelines for Traumatic Brain Injury in Prolonged Care (CPG ID:63). The Value-Burden analysis yielded a ranking of sensors as well as sensor metadata useful in the Knowledge Base.

CONCLUSION

We developed a design and tested the feasibility of a system that would allow the use of physiological biomarkers as a management tool in forward care. A key feature is the modular design that allows the system to adapt to changes in sensors, resources, and context as well as to updates in guidelines as they are developed. Continued work consists of further validation of the concept with simulated scenarios.

Severe Traumatic Brain Injury and Pulmonary Embolism: Risks, Prevention, Diagnosis and Management

Severe traumatic brain injury (sTBI) is a silent epidemic, causing approximately 300,000 intensive care unit (ICU) admissions annually, with a 30% mortality rate. Despite worldwide efforts to optimize the management of patients and improve outcomes, the level of evidence for the treatment of these patients remains low. The concomitant occurrence of thromboembolic events, particularly pulmonary embolism (PE), remains a challenge for intensivists due to the risks of anticoagulation to the injured brain. We performed a literature review on sTBI and concomitant PE to identify and report the most recent advances on this topic. We searched PubMed and Scopus for papers published in the last five years that included the terms "pulmonary embolism" and "traumatic brain injury" in their title or abstract. Exclusion criteria were papers referring to children, non-sTBI populations, and post-acute care. Our search revealed 75 papers, of which 38 are included in this review. The main topics covered include the prevalence of and risk factors for pulmonary embolism, the challenges of timely diagnosis in the ICU, the timing of pharmacological prophylaxis, and the treatment of diagnosed PE.

Acute Management of Moderate to Severe Traumatic Brain Injury

The focus of this article is on the acute management of traumatic brain injury. The article focuses on the classification of traumatic brain injury, general acute management of traumatic brain injury, the role of the physiatrist on this team, and lastly, behavioral and family considerations in the acute care setting. The article includes a focus on physiologic systems, strategies for the management of various aspects of brain injury, and consideration of factors associated with the continuum of care. Overall, the article reviews this critical period of brain injury recovery and provides a primer for the physiatrist.

Machine learning prediction models for in-hospital postoperative functional outcome after moderate-to-severe traumatic brain injury

AIM

This study aims to utilize machine learning (ML) and logistic regression (LR) models to predict surgical outcomes among patients with traumatic brain injury (TBI) based on admission examination, assisting in making optimal surgical treatment decision for these patients.

METHOD

We conducted a retrospective review of patients hospitalized in our department for moderate-to-severe TBI. Patients admitted between October 2011 and October 2022 were assigned to the training set, while patients admitted between November 2022 and May 2023 were designated as the external validation set. Five ML algorithms and LR model were employed to predict the postoperative Glasgow Outcome Scale (GOS) status at discharge using clinical and routine blood data collected upon admission. The Shapley (SHAP) plot was utilized for interpreting the models.

RESULTS

A total of 416 patients were included in this study, and they were divided into the training set (n = 396) and the external validation set (n = 47). The ML models, using both clinical and routine blood data, were able to predict postoperative GOS outcomes with area under the curve (AUC) values ranging from 0.860 to 0.900 during the internal cross-validation and from 0.801 to 0.890 during the external validation. In contrast, the LR model had the lowest AUC values during the internal and external validation (0.844 and 0.567, respectively). When blood data was not available, the ML models achieved AUCs of 0.849 to 0.870 during the internal cross-validation and 0.714 to 0.861 during the external validation. Similarly, the LR model had the lowest AUC values (0.821 and 0.638, respectively). Through repeated cross-validation analysis, we found that routine blood data had a significant association with higher mean AUC values in all ML and LR models. The SHAP plot was used to visualize the contributions of all predictors and highlighted the significance of blood data in the lightGBM model.

CONCLUSION

The study concluded that ML models could provide rapid and accurate predictions for postoperative GOS outcomes at discharge following moderate-to-severe TBI. The study also highlighted the crucial role of routine blood tests in improving such predictions, and may contribute to the optimization of surgical treatment decision-making for patients with TBI.

Xuefu Zhuyu decoction promotes synaptic plasticity by targeting miR-191a-5p/BDNF-TrkB axis in severe traumatic brain injury

BACKGROUND

Xuefu Zhuyu decoction (XFZYD) is a traditional Chinese herbal formula known for its ability to eliminate blood stasis and improve blood circulation, providing neuroprotection against severe traumatic brain injury (sTBI). However, the underlying mechanism is still unclear.

PURPOSE

We aim to investigate the neuroprotective effects of XFZYD in sTBI from a novel mechanistic perspective of miRNA-mRNA. Additionally, we sought to elucidate a potential specific mechanism by integrating transcriptomics, bioinformatics, and conducting both in vitro and in vivo experiments.

METHODS

The sTBI rat model was established, and the rats were treated with XFZYD for 14 days. The neuroprotective effects of XFZYD were evaluated using a modified neurological severity score, hematoxylin and eosin staining, as well as Nissl staining. The anti-inflammatory effects of XFZYD were explored using quantitative real-time PCR (qRT-PCR), Western blot analysis, and immunofluorescence. Next, miRNA sequencing of the hippocampus was performed to determine which miRNAs were differentially expressed. Subsequently, qRT-PCR was used to validate the differentially expressed miRNAs. Target core mRNAs were determined using various methods, including miRNA prediction targets, mRNA sequencing, miRNA-mRNA network, and protein-protein interaction (PPI) analysis. The miRNA/mRNA regulatory axis were verified through qRT-PCR or Western blot analysis. Finally, morphological changes in the neural synapses were observed using transmission electron microscopy and immunofluorescence.

RESULTS

XFZYD exhibited significant neuroprotective and anti-inflammatory effects on subacute sTBI rats' hippocampus. The analyses of miRNA/mRNA sequences combined with the PPI network revealed that the therapeutic effects of XFZYD on sTBI were associated with the regulation of the rno-miR-191a-5p/BDNF axis. Subsequently, qRT-PCR and Western blot analysis confirmed XFZYD reversed the decrease of BDNF and TrkB in the hippocampus caused by sTBI. Additionally, XFZYD treatment potentially increased the number of synaptic connections, and the expression of the synapse-related protein PSD95, axon-related protein GAP43 and neuron-specific protein TUBB3.

CONCLUSIONS

XFZYD exerts neuroprotective effects by promoting hippocampal synaptic remodeling and improving cognition during the subacute phase of sTBI through downregulating of rno-miR-191a-5p/BDNF axis, further activating BDNF-TrkB signaling.

The recent two decades of traumatic brain injury: a bibliometric analysis and systematic review

BACKGROUND

Traumatic brain injury (TBI) is a serious public health burden worldwide, with a mortality rate of 20-30%; however, reducing the incidence and mortality rates of TBI remains a major challenge. This study provides a multidimensional analysis to explore the potential breakthroughs in TBI over the past two decades.

MATERIALS AND METHODS

The authors used bibliometric and Latent Dirichlet Allocation (LDA) analyses to analyze publications focusing on TBI published between 2003 and 2022 from the Web of Science Core Collection (WOSCC) database to identify core journals and collaborations among countries/regions, institutions, authors, and research trends.

RESULTS

Over the past 20 years, 41 545 articles on TBI from 3043 journals were included, with 12 916 authors from 20 449 institutions across 145 countries/regions. The annual number of publications has increased 10-fold compared to previous publications. This study revealed that high-income countries, especially the United States, have a significant influence. Collaboration was limited to several countries/regions. The LDA results indicated that the hotspots included four main areas: 'Clinical finding', 'Molecular mechanism', 'Epidemiology', and 'Prognosis'. Epidemiological research has consistently increased in recent years. Through epidemiological topic analysis, the main etiology of TBI has shifted from traffic accidents to falls in a demographically aging society.

CONCLUSION

Over the past two decades, TBI research has developed rapidly, and its epidemiology has received increasing attention. Reducing the incidence of TBI from a preventive perspective is emerging as a trend to alleviate the future social burden; therefore, epidemiological research might bring breakthroughs in TBI.

Enhancing axonal myelination: Clemastine attenuates cognitive impairment in a rat model of diffuse traumatic brain injury

Traumatic brain injury (TBI) has a significant impact on cognitive function, affecting millions of people worldwide. Myelin loss is a prominent pathological feature of TBI, while well-functioning myelin is crucial for memory and cognition. Utilizing drug repurposing to identify effective drug candidates for TBI treatment has gained attention. Notably, recent research has highlighted the potential of clemastine, an FDA-approved allergy medication, as a promising pro-myelinating drug. Therefore, in this study, we aim to investigate whether clemastine can enhance myelination and alleviate cognitive impairment following mild TBI using a clinically relevant rat model of TBI. Mild diffuse TBI was induced using the Closed-Head Impact Model of Engineered Rotational Acceleration (CHIMERA). Animals were treated with either clemastine or an equivalent volume of the vehicle from day 1 to day 14 post-injury. Following treatment, memory-related behavioral tests were conducted, and myelin pathology in the cortex and hippocampus was assessed through immunofluorescence staining and ProteinSimple® capillary-based immunoassay. Our results showed that TBI leads to significant myelin loss, axonal damage, glial activation, and a decrease in mature oligodendrocytes in both the cortex and hippocampus. The TBI animals also exhibited notable deficits in memory-related tests. In contrast, animals treated with clemastine showed an increase in mature oligodendrocytes, enhanced myelination, and improved performance in the behavioral tests. These preliminary findings support the therapeutic value of clemastine in alleviating TBI-induced cognitive impairment, with substantial clinical translational potential. Our findings also underscore the potential of remyelinating therapies for TBI.

Dynamics of Intracranial Pressure and Cerebrovascular Reactivity During Intrahospital Transportation of Traumatic Brain Injury Patients in Coma

BACKGROUND

Intrahospital transportation (IHT) of patients with traumatic brain injury (TBI) is common and may have adverse consequences, incurring inherent risks. The data on the frequency and severity of clinical complications linked with IHT are contradictory, and there is no agreement on whether it is safe or potentially challenging for neurocritical care unit patients. Continuous intracranial pressure (ICP) monitoring is essential in neurointensive care. The role of ICP monitoring and management of cerebral autoregulation impairments in IHT of patients with severe TBI is underinvestigated. The purpose of this nonrandomized retrospective single-center study was to assess the dynamics of ICP and an improved pressure reactivity index (iPRx) as a measure of autoregulation during IHT.

METHODS

Seventy-seven men and fourteen women with severe TBI admitted in 2012-2022 with a mean age of 33.2 ± 5.2 years were studied. ICP and arterial pressure were invasively monitored, and cerebral perfusion pressure and iPRx were calculated from the measured parameters. All patients were subjected to dynamic helical computed tomography angiography using a 64-slice scanner Philips Ingenuity computed tomography scan 1-2 days after TBI. Statistical analysis of all results was done using a paired t-test, and p was preset at < 0.05. The logistic regression analysis was performed for cerebral ischemia development dependent on intracranial hypertension and cerebrovascular reactivity.

RESULTS

IHT led to an increase in ICP in all the patients, especially during vertical movement in an elevator (maximum 75.2 mm Hg). During the horizontal transportation on the floor, ICP remained increased (p < 0.05). The mean ICP during IHT was significantly higher (26.1 ± 13.5 mm Hg, p < 0.001) than that before the IHT (19.9 ± 5.3 mm Hg). The mean iPRx after and before IHT was 0.52 ± 0.04 and 0.23 ± 0.14, respectively (p < 0.001).

CONCLUSIONS

Both horizontal and vertical transportation causes a significant increase in ICP and iPRx in patients with severe TBI, potentially leading to the outcome worsening.

Artificial Intelligence and Machine Learning Applications in Critically Ill Brain Injured Patients

The utilization of Artificial Intelligence (AI) and Machine Learning (ML) is paving the way for significant strides in patient diagnosis, treatment, and prognostication in neurocritical care. These technologies offer the potential to unravel complex patterns within vast datasets ranging from vast clinical data and EEG (electroencephalogram) readings to advanced cerebral imaging facilitating a more nuanced understanding of patient conditions. Despite their promise, the implementation of AI and ML faces substantial hurdles. Historical biases within training data, the challenge of interpreting multifaceted data streams, and the "black box" nature of ML algorithms present barriers to widespread clinical adoption. Moreover, ethical considerations around data privacy and the need for transparent, explainable models remain paramount to ensure trust and efficacy in clinical decision-making.This article reflects on the emergence of AI and ML as integral tools in neurocritical care, discussing their roles from the perspective of both their scientific promise and the associated challenges. We underscore the importance of extensive validation in diverse clinical settings to ensure the generalizability of ML models, particularly considering their potential to inform critical medical decisions such as withdrawal of life-sustaining therapies. Advancement in computational capabilities is essential for implementing ML in clinical settings, allowing for real-time analysis and decision support at the point of care. As AI and ML are poised to become commonplace in clinical practice, it is incumbent upon health care professionals to understand and oversee these technologies, ensuring they adhere to the highest safety standards and contribute to the realization of personalized medicine. This engagement will be pivotal in integrating AI and ML into patient care, optimizing outcomes in neurocritical care through informed and data-driven decision-making.

Therapy Intensity Level Scale for Traumatic Brain Injury: Clinimetric Assessment on Neuro-Monitored Patients Across 52 European Intensive Care Units

Intracranial pressure (ICP) data from traumatic brain injury (TBI) patients in the intensive care unit (ICU) cannot be interpreted appropriately without accounting for the effect of administered therapy intensity level (TIL) on ICP. A 15-point scale was originally proposed in 1987 to quantify the hourly intensity of ICP-targeted treatment. This scale was subsequently modified-through expert consensus-during the development of TBI Common Data Elements to address statistical limitations and improve usability. The latest 38-point scale (hereafter referred to as TIL) permits integrated scoring for a 24-h period and has a five-category, condensed version (TIL(Basic)) based on qualitative assessment. Here, we perform a total- and component-score analysis of TIL and TIL(Basic) to: 1) validate the scales across the wide variation in contemporary ICP management; 2) compare their performance against that of predecessors; and 3) derive guidelines for proper scale use. From the observational Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) study, we extract clinical data from a prospective cohort of ICP-monitored TBI patients (n = 873) from 52 ICUs across 19 countries. We calculate daily TIL and TIL(Basic) scores (TIL24 and TIL(Basic)24, respectively) from each patient's first week of ICU stay. We also calculate summary TIL and TIL(Basic) scores by taking the first-week maximum (TILmax and TIL(Basic)max) and first-week median (TILmedian and TIL(Basic)median) of TIL24 and TIL(Basic)24 scores for each patient. We find that, across all measures of construct and criterion validity, the latest TIL scale performs significantly greater than or similarly to all alternative scales (including TIL(Basic)) and integrates the widest range of modern ICP treatments. TILmedian outperforms both TILmax and summarized ICP values in detecting refractory intracranial hypertension (RICH) during ICU stay. The RICH detection thresholds which maximize the sum of sensitivity and specificity are TILmedian ≥ 7.5 and TILmax ≥ 14. The TIL24 threshold which maximizes the sum of sensitivity and specificity in the detection of surgical ICP control is TIL24 ≥ 9. The median scores of each TIL component therapy over increasing TIL24 reflect a credible staircase approach to treatment intensity escalation, from head positioning to surgical ICP control, as well as considerable variability in the use of cerebrospinal fluid drainage and decompressive craniectomy. Since TIL(Basic)max suffers from a strong statistical ceiling effect and only covers 17% (95% confidence interval [CI]: 16-18%) of the information in TILmax, TIL(Basic) should not be used instead of TIL for rating maximum treatment intensity. TIL(Basic)24 and TIL(Basic)median can be suitable replacements for TIL24 and TILmedian, respectively (with up to 33% [95% CI: 31-35%] information coverage) when full TIL assessment is infeasible. Accordingly, we derive numerical ranges for categorising TIL24 scores into TIL(Basic)24 scores. In conclusion, our results validate TIL across a spectrum of ICP management and monitoring approaches. TIL is a more sensitive surrogate for pathophysiology than ICP and thus can be considered an intermediate outcome after TBI.

Brain Oxygenation Response to Hypercapnia in Patients with Acute Brain Injury

BACKGROUND

Cerebral hypoxia is a frequent cause of secondary brain damage in patients with acute brain injury. Although hypercapnia can increase intracranial pressure, it may have beneficial effects on tissue oxygenation. We aimed to assess the effects of hypercapnia on brain tissue oxygenation (PbtO2).

METHODS

This single-center retrospective study (November 2014 to June 2022) included all patients admitted to the intensive care unit after acute brain injury who required multimodal monitoring, including PbtO2 monitoring, and who underwent induced moderate hypoventilation and hypercapnia according to the decision of the treating physician. Patients with imminent brain death were excluded. Responders to hypercapnia were defined as those with an increase of at least 20% in PbtO2 values when compared to their baseline levels.

RESULTS

On a total of 163 eligible patients, we identified 23 (14%) patients who underwent moderate hypoventilation (arterial partial pressure of carbon dioxide [PaCO2] from 44 [42-45] to 50 [49-53] mm Hg; p < 0.001) during the study period at a median of 6 (4-10) days following intensive care unit admission; six patients had traumatic brain injury, and 17 had subarachnoid hemorrhage. A significant overall increase in median PbtO2 values from baseline (21 [19-26] to 24 [22-26] mm Hg; p = 0.02) was observed. Eight (35%) patients were considered as responders, with a median increase of 7 (from 4 to 11) mm Hg of PbtO2, whereas nonresponders showed no changes (from - 1 to 2 mm Hg of PbtO2). Because of the small sample size, no variable independently associated with PbtO2 response was identified. No correlation between changes in PaCO2 and in PbtO2 was observed.

CONCLUSIONS

In this study, a heterogeneous response of PbtO2 to induced hypercapnia was observed but without any deleterious elevations of intracranial pressure.

Trending Ability of End-Tidal Capnography Monitoring During Mechanical Ventilation to Track Changes in Arterial Partial Pressure of Carbon Dioxide in Critically Ill Patients With Acute Brain Injury: A Monocenter Retrospective Study

BACKGROUND

Changes in arterial partial pressure of carbon dioxide (Pa co2 ) may alter cerebral perfusion in critically ill patients with acute brain injury. Consequently, international guidelines recommend normocapnia in mechanically ventilated patients with acute brain injury. The measurement of end-tidal capnography (Et co2 ) allows its approximation. Our objective was to report the agreement between trends in Et co2 and Pa co2 during mechanical ventilation in patients with acute brain injury.

METHODS

Retrospective monocenter study was conducted for 2 years. Critically ill patients with acute brain injury who required mechanical ventilation with continuous Et co2 monitoring and with 2 or more arterial gas were included. The agreement was evaluated according to the Bland and Altman analysis for repeated measurements with calculation of bias, and upper and lower limits of agreement. The directional concordance rate of changes between Et co2 and Pa co2 was evaluated with a 4-quadrant plot. A polar plot analysis was performed using the Critchley methods.

RESULTS

We analyzed the data of 255 patients with a total of 3923 paired ΔEt co2 and ΔPa co2 (9 values per patient in median). Mean bias by Bland and Altman analysis was -8.1 (95 CI, -7.9 to -8.3) mm Hg. The directional concordance rate between Et co2 and Pa co2 was 55.8%. The mean radial bias by polar plot analysis was -4.4° (95% CI, -5.5 to -3.3) with radial limit of agreement (LOA) of ±62.8° with radial LOA 95% CI of ±1.9°.

CONCLUSIONS

Our results question the performance of trending ability of Et co2 to track changes in Pa co2 in a population of critically ill patients with acute brain injury. Changes in Et co2 largely failed to follow changes in Pa co2 in both direction (ie, low concordance rate) and magnitude (ie, large radial LOA). These results need to be confirmed in prospective studies to minimize the risk of bias.

Early systemic insults following traumatic brain injury: association with biomarker profiles, therapy for intracranial hypertension, and neurological outcomes-an analysis of CENTER-TBI data

PURPOSE

We analysed the impact of early systemic insults (hypoxemia and hypotension, SIs) on brain injury biomarker profiles, acute care requirements during intensive care unit (ICU) stay, and 6-month outcomes in patients with traumatic brain injury (TBI).

METHODS

From patients recruited to the Collaborative European neurotrauma effectiveness research in TBI (CENTER-TBI) study, we documented the prevalence and risk factors for SIs and analysed their effect on the levels of brain injury biomarkers [S100 calcium-binding protein B (S100B), neuron-specific enolase (NSE), neurofilament light (NfL), glial fibrillary acidic protein (GFAP), ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), and protein Tau], critical care needs, and 6-month outcomes [Glasgow Outcome Scale Extended (GOSE)].

RESULTS

Among 1695 TBI patients, 24.5% had SIs: 16.1% had hypoxemia, 15.2% had hypotension, and 6.8% had both. Biomarkers differed by SI category, with higher S100B, Tau, UCH-L1, NSE and NfL values in patients with hypotension or both SIs. The ratio of neural to glial injury (quantified as UCH-L1/GFAP and Tau/GFAP ratios) was higher in patients with hypotension than in those with no SIs or hypoxia alone. At 6 months, 380 patients died (22%), and 759 (45%) had GOSE ≤ 4. Patients who experienced at least one SI had higher mortality than those who did not (31.8% vs. 19%, p < 0.001).

CONCLUSION

Though less frequent than previously described, SIs in TBI patients are associated with higher release of neuronal than glial injury biomarkers and with increased requirements for ICU therapies aimed at reducing intracranial hypertension. Hypotension or combined SIs are significantly associated with adverse 6-month outcomes. Current criteria for hypotension may lead to higher biomarker levels and more negative outcomes than those for hypoxemia suggesting a need to revisit pressure targets in the prehospital settings.

Secondary insults prevalence, co-occurrence and relationship with outcome after severe TBI

Introduction

Secondary insults due to high intracranial pressure (ICP), low cerebral perfusion pressure (CPP) and impaired cerebral pressure reactivity (PRx) predict outcome after severe traumatic brain injury (TBI).

Research question

What is the prevalence, co-occurrence and prognostic importance of secondary insults due to deranged ICP, CPP or PRx after TBI.

Material and methods

Severe TBI patients requiring ICP monitoring were included. Secondary insults due to ICP, PRx, and CPP were defined as having at least 1 h with a mean value above (or below for CPP) a respective threshold (ICP 20, CPP 60, and PRx 0.25). Percentage time with isolated or co-occurring insults was calculated (impaired ICP only, CPP only, PRx only, ICP and PRx, ICP and CPP, CPP and PRx, ICP CPP and PRx). Prognostic importance for mortality was assessed using a logistic regression model.

Results

822 patients were included of which 76% had elevated ICP, 92% had disturbed pressure reactivity and 55% had low CPP for at least an hour. Out of the total 115,459 h, 46,111 (40%) were spent with at least one variable within the defined secondary injury range. Odds ratios for mortality were greater for combined (impaired ICP, CPP and PRx OR 1.17 95%CI 1.09 to 1.28) than isolated insults (impaired ICP only OR 1.01 95%CI 1.00-1.02, impaired CPP only 1.00 95%CI 0.95-1.05).

Discussion and conclusion

ICP and autoregulation insults are common after TBI and often occur independently. Concurrent ICP, CPP and PRx insults portend worse prognosis than when a single variable is deranged.

Machine learning models for predicting in-hospital outcomes after non-surgical treatment among patients with moderate-to-severe traumatic brain injury

AIM

This study aims to develop prediction models for in-hospital outcomes after non-surgical treatment among patients with moderate-to-severe traumatic brain injury (TBI).

METHOD

We conducted a retrospective review of patients hospitalized for moderate-to-severe TBI in our department from 2011 to 2020. Five machine learning (ML) algorithms and the conventional logistic regression (LR) model were employed to predict in-hospital mortality and the Glasgow Outcome Scale (GOS) functional outcomes. These models utilized clinical and routine blood data collected upon admission.

RESULTS

This study included a total of 196 patients who received only non-surgical treatment after moderate-to-severe TBI. When predicting mortality, ML models achieved area under the curve (AUC) values of 0.921 to 0.994 using clinical and routine blood data, and 0.877 to 0.982 using only clinical data. In comparison, LR models yielded AUCs of 0.762 and 0.730 respectively. When predicting the GOS outcome, ML models achieved AUCs of 0.870 to 0.915 using clinical and routine blood data, and 0.858 to 0.927 using only clinical data. In comparison, the LR model yielded AUCs of 0.798 and 0.787 respectively. Repeated internal validation showed that the contributions of routine blood data for prediction models may depend on different prediction algorithms and different outcome measurements.

CONCLUSION

The study reported ML-based prediction models that provided rapid and accurate predictions on short-term outcomes after non-surgical treatment among patients with moderate-to-severe TBI. The study also highlighted the superiority of ML models over conventional LR models and proposed the complex contributions of routine blood data in such predictions.