Beta blockers in critically ill patients with traumatic brain injury: Results from a multicenter, prospective, observational American Association for the Surgery of Trauma study

Early Beta-Blocker Utilization in Critically Ill Patients With Moderate-Severe Traumatic Brain Injury: A Retrospective Cohort Study

BACKGROUND

There is limited evidence that beta-blockers may provide benefit for patients with moderate-severe traumatic brain injury (TBI) during the acute injury period. Larger studies on utilization patterns and impact on outcomes in clinical practice are lacking.

OBJECTIVE

The present study uses a large, national hospital claims-based dataset to examine early beta-blocker utilization patterns and its association with clinical outcomes among critically ill patients with moderate-severe TBI.

METHODS

We conducted a retrospective cohort study of the administrative claims Premier Healthcare Database of adults (≥17 years) with moderate-severe TBI admitted to the intensive care unit (ICU) from 2016 to 2020. The exposure was receipt of a beta-blocker during day 1 or 2 of ICU stay (BB+). The primary outcome was hospital mortality, and secondary outcomes were: hospital length of stay (LOS), ICU LOS, discharge to home, and vasopressor utilization. In a sensitivity analysis, we explored the association of beta-blocker class (cardioselective and noncardioselective) with hospital mortality. We used propensity weighting methods to address possible confounding by treatment indication.

RESULTS

A total of 109 665 participants met inclusion criteria and 39% (n = 42 489) were exposed to beta-blockers during the first 2 days of hospitalization. Of those, 42% received cardioselective only, 43% received noncardioselective only, and 14% received both. After adjustment, there was no association with hospital mortality in the BB+ group compared to the BB- group (adjusted odds ratio [OR] = 0.99, 95% confidence interval [CI] = 0.94, 1.04). The BB+ group had longer hospital stays, lower chance of discharged home, and lower risk of vasopressor utilization, although these difference were clinically small. Beta-blocker class was not associated with hospital mortality.

CONCLUSION

In this retrospective cohort study, we found variation in use of beta-blockers and early exposure was not associated with hospital mortality. Further research is necessary to understand the optimal type, dose, and timing of beta-blockers for this population.

Beta-Blockers as an Immunologic and Autonomic Manipulator in Critically Ill Patients: A Review of the Recent Literature

The autonomic nervous system plays a key role in maintaining body hemostasis through both the sympathetic and parasympathetic nervous systems. Sympathetic overstimulation as a reflex to multiple pathologies, such as septic shock, brain injury, cardiogenic shock, and cardiac arrest, could be harmful and lead to autonomic and immunologic dysfunction. The continuous stimulation of the beta receptors on immune cells has an inhibitory effect on these cells and may lead to immunologic dysfunction through enhancing the production of anti-inflammatory cytokines, such as interleukin-10 (IL-10), and inhibiting the production of pro-inflammatory factors, such as interleukin-1B IL-1B and tissue necrotizing factor-alpha (TNF-alpha). Sympathetic overstimulation-induced autonomic dysfunction may also happen due to adrenergic receptor insensitivity or downregulation. Administering anti-adrenergic medication, such as beta-blockers, is a promising treatment to compensate against the undesired effects of adrenergic surge. Despite many misconceptions about beta-blockers, beta-blockers have shown a promising effect in decreasing mortality in patients with critical illness. In this review, we summarize the recently published articles that have discussed using beta-blockers as a promising treatment to decrease mortality in critically ill patients, such as patients with septic shock, traumatic brain injury, cardiogenic shock, acute decompensated heart failure, and electrical storm. We also discuss the potential pathophysiology of beta-blockers in various types of critical illness. More clinical trials are encouraged to evaluate the safety and effectiveness of beta-blockers in improving mortality among critically ill patients.

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 ).

Preclinical Studies on Mechanisms Underlying the Protective Effects of Propranolol in Traumatic Brain Injury: A Systematic Review

Traumatic brain injury (TBI) is a leading cause of mortality and morbidity amongst trauma patients. Its treatment is focused on minimizing progression to secondary injury. Administration of propranolol for TBI maydecrease mortality and improve functional outcomes. However, it is our sense that its use has not been universally adopted due to low certainty evidence. The literature was reviewed to explore the mechanism of propranolol as a therapeutic intervention in TBI to guide future clinical investigations. Medline, Embase, and Scopus were searched for studies that investigated the effect of propranolol on TBI in animal models from inception until June 6, 2023. All routes of administration for propranolol were included and the following outcomes were evaluated: cognitive functions, physiological and immunological responses. Screening and data extraction were done independently and in duplicate. The risk of bias for each individual study was assessed using the SYCLE's risk of bias tool for animal studies. Three hundred twenty-three citations were identified and 14 studies met our eligibility criteria. The data suggests that propranolol may improve post-TBI cognitive and motor function by increasing cerebral perfusion, reducing neural injury, cell death, leukocyte mobilization and p-tau accumulation in animal models. Propranolol may also attenuate TBI-induced immunodeficiency and provide cardioprotective effects by mitigating damage to the myocardium caused by oxidative stress. This systematic review demonstrates that propranolol may be therapeutic in TBI by improving cognitive and motor function while regulating T lymphocyte response and levels of myocardial reactive oxygen species. Oral or intravenous injection of propranolol following TBI is associated with improved cerebral perfusion, reduced neuroinflammation, reduced immunodeficiency, and cardio-neuroprotection in preclinical studies.

Traumatic Brain Injury and Traumatic Spinal Cord Injury

OBJECTIVE

This article reviews the mechanisms of primary traumatic injury to the brain and spinal cord, with an emphasis on grading severity, identifying surgical indications, anticipating complications, and managing secondary injury.

LATEST DEVELOPMENTS

Serum biomarkers have emerged for clinical decision making and prognosis after traumatic injury. Cortical spreading depolarization has been identified as a potentially modifiable mechanism of secondary injury after traumatic brain injury. Innovative methods to detect covert consciousness may inform prognosis and enrich future studies of coma recovery. The time-sensitive nature of spinal decompression is being elucidated.

ESSENTIAL POINTS

Proven management strategies for patients with severe neurotrauma in the intensive care unit include surgical decompression when appropriate, the optimization of perfusion, and the anticipation and treatment of complications. Despite validated models, predicting outcomes after traumatic brain injury remains challenging, requiring prognostic humility and a model of shared decision making with surrogate decision makers to establish care goals. Penetrating injuries, especially gunshot wounds, are often devastating and require public health and policy approaches that target prevention.

Dysregulated brain-gut axis in the setting of traumatic brain injury: review of mechanisms and anti-inflammatory pharmacotherapies

Traumatic brain injury (TBI) is a chronic and debilitating disease, associated with a high risk of psychiatric and neurodegenerative diseases. Despite significant advancements in improving outcomes, the lack of effective treatments underscore the urgent need for innovative therapeutic strategies. The brain-gut axis has emerged as a crucial bidirectional pathway connecting the brain and the gastrointestinal (GI) system through an intricate network of neuronal, hormonal, and immunological pathways. Four main pathways are primarily implicated in this crosstalk, including the systemic immune system, autonomic and enteric nervous systems, neuroendocrine system, and microbiome. TBI induces profound changes in the gut, initiating an unrestrained vicious cycle that exacerbates brain injury through the brain-gut axis. Alterations in the gut include mucosal damage associated with the malabsorption of nutrients/electrolytes, disintegration of the intestinal barrier, increased infiltration of systemic immune cells, dysmotility, dysbiosis, enteroendocrine cell (EEC) dysfunction and disruption in the enteric nervous system (ENS) and autonomic nervous system (ANS). Collectively, these changes further contribute to brain neuroinflammation and neurodegeneration via the gut-brain axis. In this review article, we elucidate the roles of various anti-inflammatory pharmacotherapies capable of attenuating the dysregulated inflammatory response along the brain-gut axis in TBI. These agents include hormones such as serotonin, ghrelin, and progesterone, ANS regulators such as beta-blockers, lipid-lowering drugs like statins, and intestinal flora modulators such as probiotics and antibiotics. They attenuate neuroinflammation by targeting distinct inflammatory pathways in both the brain and the gut post-TBI. These therapeutic agents exhibit promising potential in mitigating inflammation along the brain-gut axis and enhancing neurocognitive outcomes for TBI patients.

A Modern Approach to the Treatment of Traumatic Brain Injury

Background: Traumatic brain injury manifests itself in various forms, ranging from mild impairment of consciousness to severe coma and death. Traumatic brain injury remains one of the leading causes of morbidity and mortality. Currently, there is no therapy to reverse the effects associated with traumatic brain injury. New neuroprotective treatments for severe traumatic brain injury have not achieved significant clinical success. Methods: A literature review was performed to summarize the recent interdisciplinary findings on management of traumatic brain injury from both clinical and experimental perspective. Results: In the present review, we discuss the concepts of traditional and new approaches to treatment of traumatic brain injury. The recent development of different drug delivery approaches to the central nervous system is also discussed. Conclusions: The management of traumatic brain injury could be aimed either at the pathological mechanisms initiating the secondary brain injury or alleviating the symptoms accompanying the injury. In many cases, however, the treatment should be complex and include a variety of medical interventions and combination therapy.

Early Intravenous Beta-Blockade with Esmolol in Adults with Severe Traumatic Brain Injury (EBB-TBI): Protocol for a Phase 2a Intervention Design Study

Traumatic brain injury is a leading cause of death and disability worldwide. Interventions that mitigate secondary brain injury have the potential to improve outcomes for patients and reduce the impact on communities and society. Increased circulating catecholamines are associated with worse outcomes and there are supportive animal data and indications in human studies of benefit from beta-blockade after severe traumatic brain injury. Here, we present the protocol for a dose-finding study using esmolol in adults commenced within 24 h of severe traumatic brain injury. Esmolol has practical advantages and theoretical benefits as a neuroprotective agent in this setting, but these must be balanced against the known risk of secondary injury from hypotension. The aim of this study is to determine a dose schedule for esmolol, using the continual reassessment method, that combines a clinically significant reduction in heart rate as a surrogate for catecholamine drive with maintenance of cerebral perfusion pressure. The maximum tolerated dosing schedule for esmolol can then be tested for patient benefit in subsequent randomized controlled trials.Trial registration ISRCTN, ISRCTN11038397, registered retrospectively 07/01/2021 https://www.isrctn.com/ISRCTN11038397.

Prognostic Impact of Early Administration of β-Blockers in Critically Ill Patients with Acute Myocardial Infarction

In critically ill patients with acute myocardial infarction (AMI), the relationship between the early administration of β-blockers and the risks of in-hospital and long-term mortality remains controversial. Furthermore, there are conflicting evidences for the efficacy of the early administration of intravenous followed by oral β-blockers in AMI. We conducted a retrospective analysis of critically ill patients with AMI who received the early administration of β-blockers within 24 hours of admission. The data were extracted from the Medical Information Mart for Intensive Care IV database. We enrolled 2467 critically ill patients with AMI in the study, with 1355 patients who received the early administration of β-blockers and 1112 patients who were non-users. Kaplan-Meier survival analysis and Cox proportional hazards models showed that the early administration of β-blockers was associated with a lower risk of in-hospital mortality (adjusted hazard ratio [aHR] 0.52; 95% confidence interval [95%CI] 0.42-0.64), 1-year mortality (aHR 0.54, 95%CI 0.47-0.63), and 5-year mortality (aHR 0.60, 95%CI 0.52-0.69). Furthermore, the early administration of both oral β-blockers and intravenous β-blockers followed by oral β-blockers may reduce the mortality risk, compared with non-users. The risks of in-hospital and long-term mortality were significantly decreased in patients who underwent revascularization with the early administration of β-blockers. We found that the early administration of β-blockers could lower the risks of in-hospital and long-term mortality. Furthermore, the early administration of both oral β-blockers and intravenous β-blockers followed by oral β-blockers may reduce the mortality risk, compared with non-users. Notably, patients who underwent revascularization with the early administration of β-blockers showed the lowest risks of in-hospital and long-term mortality.

THE NEUROENDOTHELIAL AXIS IN TRAUMATIC BRAIN INJURY: MECHANISMS OF MULTIORGAN DYSFUNCTION, NOVEL THERAPIES, AND FUTURE DIRECTIONS

ABSTRACT

Severe traumatic brain injury (TBI) often initiates a systemic inflammatory response syndrome, which can potentially culminate into multiorgan dysfunction. A central player in this cascade is endotheliopathy, caused by perturbations in homeostatic mechanisms governed by endothelial cells due to injury-induced coagulopathy, heightened sympathoadrenal response, complement activation, and proinflammatory cytokine release. Unique to TBI is the potential disruption of the blood-brain barrier, which may expose neuronal antigens to the peripheral immune system and permit neuroinflammatory mediators to enter systemic circulation, propagating endotheliopathy systemically. This review aims to provide comprehensive insights into the "neuroendothelial axis" underlying endothelial dysfunction after TBI, identify potential diagnostic and prognostic biomarkers, and explore therapeutic strategies targeting these interactions, with the ultimate goal of improving patient outcomes after severe TBI.

The effect of amantadine on acute cognitive disability after severe traumatic brain injury: An institutional pilot study

BACKGROUND

Amantadine is used in the post-acute care setting to improve cognitive function after a traumatic brain injury. Its utility in the acute postinjury period is unknown. In this pilot study, we sought to examine the effect of amantadine on short-term cognitive disability among patients with a severe traumatic brain injury and hypothesized that patients receiving amantadine would have a greater improvement in disability throughout their acute hospitalization.

METHODS

We performed a prospective, observational study of patients ≥18 years with severe traumatic brain injury (Glasgow Coma Scale ≤8) at a level I trauma center between 2020 and 2022. Patients with penetrating trauma, death within 48 hours of admission, and no radiographic evidence of intracranial pathology were excluded. Patients were grouped according to whether they received amantadine. Our primary outcome was the change in cognitive disability, measured by the Disability Rating Scale (DRS), over the index hospitalization.

RESULTS

There were 55 patients in the cohort: 41.8% (n = 23) received amantadine and 58.2% (n = 32) did not. There were higher rates of motor vehicle collisions (65.2% vs 46.9%, P = .02), diffuse axonal injury (47.8% vs 18.8%, P = .02), intracranial pressure monitor use (73.9% vs 21.9%, P = .0001), and propranolol use (73.9% vs 21.9%, P = .0001) in the amantadine. There was a larger improvement in DRS scores among patients receiving amantadine (7.8 vs 3.6, P = .001), and amantadine independently predicted improvement in DRS scores (β, 1.61; 95% confidence interval, 0.20-3.02, P = .03). Rates of discharge to traumatic brain injury rehabilitation were significantly higher in the amantadine group (73.9% vs 21.9%, P = .0002).

CONCLUSION

Among patients with severe traumatic brain injury, amantadine use in the acute postinjury period may be associated with an improvement in cognitive disability and discharge to traumatic brain injury rehabilitation.

Effects of beta-blockers use on mortality of patients with acute respiratory distress syndrome: a retrospective cohort study

Introduction: Acute respiratory distress syndrome (ARDS) remains a challenging disease with limited prevention and treatment options. The usage of beta-blockers may have potential benefits in different critical illnesses. This study aimed to investigate the correlation between beta-blocker therapy and mortality in patients with ARDS. Materials and methods: This retrospective cohort study utilized data from the Medical Information Mart for Intensive Care (MIMIC) IV database and focused on patients diagnosed with ARDS. The primary outcome of the study was 30-day mortality. To account for confounding factors, a multivariable analysis was performed. Propensity score matching (PSM) was carried out on a 1:1 ratio. Robust assessments were conducted using inverse probability weighting (IPTW), standardized mortality ratio weighting (SMRW), pairwise algorithms (PA), and overlap weights (OW). Results: A total of 1,104 patients with ARDS were included in the study. Univariate and multivariate Cox regression analyses found that the 30-day mortality for 489 patients (23.7%) who received beta-blockers was significantly lower than the mortality rate of 615 patients (35.9%) who did not receive beta-blockers. After adjusting for potential confounders through PSM and propensity score, as well as utilizing IPTW, SMRW, PA, and OW, the results remained robust, with the hazard ratios (HR) ranging from 0.42 to 0.58 and all p-values < 0.001. Evaluation of the E-values indicated the robustness of the results even in the presence of unmeasured confounding. Conclusion: The findings suggest a potential association between beta-blocker usage and reduced mortality in critically ill patients with ARDS. However, further validation of this observation is needed through randomized controlled trials.

Cerebrovascular Pressure Reactivity Measures: Index Comparison and Clinical Outcome in Patients With Traumatic Brain Injury Treated According to an Intracranial Pressure-Focused Management: Rejection of the Null Hypothesis

The aim was to investigate whether the pressure reactivity indices PRx, long-PRx (L-PRx), and pressure reactivity (PR) are interchangeable as measures of vascular reactivity, and whether they correlate with clinical outcome when an intracranial pressure (ICP)-targeted treatment regimen is applied in patients with traumatic brain injury (TBI). Patients with TBI (n = 29) that arrived at the hospital within 24 h of injury were included. PRx and L-PRx were derived from Pearson correlations between mean arterial pressure (MAP) and ICP over a short- and long-time interval. PR was the regression coefficient between the hourly mean values of ICP and MAP. Indices were compared to each other, parameters at admission, and outcome assessed by the extended Glasgow Outcome Scale-Extended (GOSE) at 6 and 12 months. PRx and L-PRx had the strongest correlation with each other (R = 0.536, p < 0.01). A correlation was also noted between L-PRx and PR (R = 0.475, p < 0.01), but not between PRx and PR. A correlation was found between age and PRx (R = 0.482, p = 0.01). No association with outcome for any of the indices was found. PRx/L-PRx and L-PRx/PR were moderately correlated with each other. Age was associated with PRx. None of the indices correlated with outcome when our ICP treatment regime was applied. Part of our null hypothesis, that the three indices are associated with outcome, must be rejected. There was, however, an association between some of the indices. To further understand the relation of treatment regimes and pressure reactivity indices, a larger, randomized study is warranted.

Clonidine safety and effectiveness in the management of suspected paroxysmal sympathetic hyperactivity post-traumatic brain injury: A retrospective cohort study

INTRODUCTION

Traumatic brain injury (TBI) is a leading cause of mortality and morbidity worldwide. In addition, TBI may cause paroxysmal sympathetic hyperactivity (PSH), which is associated with poor clinical outcomes. This study aimed to evaluate the safety and effectiveness of clonidine in patients with TBI and suspected PSH.

METHODS

A retrospective cohort study for critically ill patients with TBI with suspected PSH admitted to intensive care units (ICUs) from 1 May 2016 to 31 January 2020 at a tertiary academic medical center. Eligible patients were categorized based on clonidine use during their ICU stay (Clonidine group vs. Control group). The primary outcome was the improvement in functional outcomes during ICU stay, defined by a delta Glasgow Coma Score (GCS). Secondary outcomes included ICU and hospital length of stay, heart rate variation, and 90-day mortality.

RESULTS

A total of 2915 patients were screened, of which 169 were included. Based on multiple regression analysis, patients who received clonidine showed better improvement in functional outcomes by a higher mean delta GCS than patients who did not (Beta Coeff. 0.41; CI: 0.07 - 0.74; P = 0.02). In addition, the patient's GCS upon ICU discharge and IV opioids requirement on day three were higher in the clonidine group than control (beta coefficient (95% CI): 0.18 (0.03, 0.32); p = 0.02 and beta coefficient (95% CI): 1.38 (0.24, 2.52); p = 0.02, respectively). No statistical differences were observed in any of the other secondary outcomes after adjusting for confounders.

CONCLUSION

This study found that patients who received clonidine had better functional outcomes during their ICU stay, as shown by their delta GCS than those who did not. Other outcomes were similar between the groups. More data are needed to explore the role of clonidine in patients with TBI with suspected PSH.

Major Publications in the Critical Care Pharmacotherapy Literature: 2022

OBJECTIVES

A number of trials related to critical care pharmacotherapy were published in 2022. We aimed to summarize the most influential publications related to the pharmacotherapeutic care of critically ill patients in 2022.

DATA SOURCES

PubMed/Medical Literature Analysis and Retrieval System Online and the Clinical Pharmacy and Pharmacology Pharmacotherapy Literature Update.

STUDY SELECTION

Randomized controlled trials, prospective studies, or systematic review/meta-analyses of adult critically ill patients assessing a pharmacotherapeutic intervention and reporting clinical endpoints published between January 1, 2022, and December 31, 2022, were included in this article.

DATA EXTRACTION

Articles from a systematic search and the Clinical Pharmacy and Pharmacology Pharmacotherapy Literature Update were included and stratified into clinical domains based upon consistent themes. Consensus was obtained on the most influential publication within each clinical domain utilizing an a priori defined three-round modified Delphi process with the following considerations: 1) overall contribution to scientific knowledge and 2) novelty to the literature.

DATA SYNTHESIS

The systematic search and Clinical Pharmacy and Pharmacology Pharmacotherapy Literature Update yielded a total of 704 articles, of which 660 were excluded. The remaining 44 articles were stratified into the following clinical domains: emergency/neurology, cardiovascular, gastroenterology/fluids/nutrition, hematology, infectious diseases/immunomodulation, and endocrine/metabolic. The final article selected from each clinical domain was summarized following a three-round modified Delphi process and included three randomized controlled trials and three systematic review/meta-analyses. Article topics summarized included dexmedetomidine versus other sedatives during mechanical ventilation, beta-blocker treatment in the critically ill, restriction of IV fluids in septic shock, venous thromboembolism prophylaxis in critically ill adults, duration of antibiotic therapy for Pseudomonas aeruginosa ventilator-associated pneumonia, and low-dose methylprednisolone treatment in severe community-acquired pneumonia.

CONCLUSIONS

This concise review provides a perspective on articles published in 2022 that are relevant to the pharmacotherapeutic care of critically ill patients and their potential impact on clinical practice.

Alpha-methyltyrosine reduces the acute cardiovascular and behavioral sequelae in a murine model of traumatic brain injury

BACKGROUND

Increased catecholamines contribute to heightened cardiovascular reactivity and behavioral deficits after traumatic brain injury (TBI); adrenergic receptor blockade has limited success in reducing adverse sequelae of TBI. Injury-induced increases in the synthesis of catecholamines could contribute to adverse outcomes in TBI. Inhibition of catecholamine synthesis with alpha-methyltyrosine (αMT) could offer a benefit after TBI.

METHODS

Original research trial in mice randomized to αMT (50 mg·kg -1 ·d -1 ) or vehicle for 1 week after TBI induced by controlled cortical impact. Primary outcomes of cardiovascular reactivity and behavioral deficits were assessed after 1 week. Secondary outcomes included blood brain barrier permeability and quantification of gene transcription whose products determine intraneuronal chloride concentrations, the release of catecholamines, and activation of the sympathetic nervous system. These genes were the alpha-2 adrenergic receptor ("Adra2c"), the sodium-potassium-chloride cotransporter ("Nkcc1"), and the potassium chloride cotransporter ("Kcc2"). We also assessed the effect of TBI and αMT on the neuronal chloride/bicarbonate exchanger ("Ae3").

RESULTS

Traumatic brain injury-induced increases in blood pressure and cardiac reactivity were blocked by αMT. Inhibition of catecholamine synthesis decreased blood brain barrier leakage and improved behavioral outcomes after TBI. Traumatic brain injury diminished the transcription of Adra2c and enhanced expression of Nkcc1 while reducing Kcc2 transcription; αMT prevented the induction of the Nkcc1 by TBI without reversing the effects of TBI on Kcc2 expression; αMT also diminished Ae3 transcription.

CONCLUSION

Traumatic brain injury acutely increases cardiovascular reactivity and induces behavioral deficits in an αMT-sensitive manner, most likely by inducing Nkcc1 gene transcription. Alpha-methyltyrosine may prove salutary in the treatment of TBI by attenuating the enhanced expression of Nkcc1, minimizing blood brain barrier leakage, and diminishing central catecholamine and sympathetic output. We also found an unreported relationship between Kcc2 and the chloride/bicarbonate exchanger, which should be considered in the design of trials planned to manipulate central intraneuronal chloride concentrations following acute brain injury.

Association of Early Beta-Blocker Exposure and Functional Outcomes in Critically Ill Patients With Moderate to Severe Traumatic Brain Injury: A Transforming Clinical Research and Knowledge in Traumatic Brain Injury Study

OBJECTIVES

We aimed to 1) describe patterns of beta-blocker utilization among critically ill patients following moderate-severe traumatic brain injury (TBI) and 2) examine the association of early beta-blocker exposure with functional and clinical outcomes following injury.

DESIGN

Retrospective cohort study.

SETTING

ICUs at 18 level I, U.S. trauma centers in the Transforming Clinical Research and Knowledge in TBI (TRACK-TBI) study.

PATIENTS

Greater than or equal to 17 years enrolled in the TRACK-TBI study with moderate-severe TBI (Glasgow Coma Scale of <13) were admitted to the ICU after a blunt TBI.

INTERVENTIONS

None.

MEASUREMENTS

Primary exposure was a beta blocker during the first 7 days in the ICU, with a primary outcome of 6-month Glasgow Outcome Scale-Extended (GOSE). Secondary outcomes included: length of hospital stay, in-hospital mortality, 6-month and 12-month mortality, 12-month GOSE score, and 6-month and 12-month measures of disability, well-being, quality of life, and life satisfaction.

MAIN RESULTS

Of the 450 eligible participants, 57 (13%) received early beta blockers (BB+ group). The BB+ group was on average older, more likely to be on a preinjury beta blocker, and more likely to have a history of hypertension. In the BB+ group, 34 participants (60%) received metoprolol only, 19 participants (33%) received propranolol only, 3 participants (5%) received both, and 1 participant (2%) received atenolol only. In multivariable regression, there was no difference in the odds of a higher GOSE score at 6 months between the BB+ group and BB- group (odds ratio = 0.86; 95% CI, 0.48-1.53). There was no association between BB exposure and secondary outcomes.

CONCLUSIONS

About one-sixth of subjects in our study received early beta blockers, and within this group, dose, and timing of beta-blocker administration varied substantially. No significant differences in GOSE score at 6 months were demonstrated, although our ability to draw conclusions is limited by overall low total doses administered compared with prior studies.

Association of Discontinuing Preinjury Beta-Adrenergic Blockade Medications With Mortality in Severe Blunt Traumatic Brian Injury

Background

Beta-adrenergic receptor blocker (BB) administration has been shown to improve survival after traumatic brain injury (TBI). However, studies to date that observe a benefit did not distinguish between continuation of preinjury BB versus de novo initiation of BB.

Objectives

To determine the effect of continuation of preinjury BB and de novo initiation of BB on risk-adjusted mortality and complications for patients with TBI.

Methods

Trauma quality collaborative data (2016-2021) were analyzed. Patients were excluded with hospitalization <48 hours, direct admission, or penetrating injury. Severe TBI was identified as a head abbreviated injury scale (AIS) value of 3 to 5. Patients were placed into 4 groups based on the preinjury BB use and administration of BB during hospitalization. Propensity score matching was used to create 1:1 matched cohorts of patients for comparisons. Odd ratios of mortality accounting for hospital clustering were calculated. A sensitivity analysis was performed excluding patients with AIS >2 injuries in all other body regions to create a cohort of isolated TBI patients.

Results

A total of 15,153 patients treated at 35 trauma centers were available for analysis. Patients were divided into 4 cohort groupings related to preinjury BB use and postinjury receipt of BB. The odds of mortality was significantly reduced for patients with a TBI on a preinjury BB who had the medication continued in the acute setting (as compared with patients on preinjury BB who did not) (odds ratio [OR], 0.73; 95% confidence interval [CI], 0.54-0.98; P = 0.04). Patients with a TBI who were not on preinjury BB did not benefit from de novo initiation of BB with regard to mortality (OR, 0.83; 95% CI, 0.64-1.08; P = 0.2). In the sensitivity analysis, excluding polytrauma patients, patients on preinjury BB who had BB continued had a reduction in mortality when compared with patients in which BB was stopped following a TBI (OR, 0.65; 95% CI, 0.47-0.91; P = 0.01).

Conclusions

Continuing BB is associated with reduced odds of mortality in patients with a TBI on preinjury BB. We were unable to demonstrate benefit from instituting beta blockade in patients who are not on a BB preinjury.

Effect of propranolol and clonidine after severe traumatic brain injury: a pilot randomized clinical trial

OBJECTIVE

To evaluate the safety, feasibility, and efficacy of combined adrenergic blockade with propranolol and clonidine in patients with severe traumatic brain injury (TBI).

BACKGROUND

Administration of adrenergic blockade after severe TBI is common. To date, no prospective trial has rigorously evaluated this common therapy for benefit.

METHODS

This phase II, single-center, double-blinded, pilot randomized placebo-controlled trial included patients aged 16-64 years with severe TBI (intracranial hemorrhage and Glasgow Coma Scale score ≤ 8) within 24 h of ICU admission. Patients received propranolol and clonidine or double placebo for 7 days. The primary outcome was ventilator-free days (VFDs) at 28 days. Secondary outcomes included catecholamine levels, hospital length of stay, mortality, and long-term functional status. A planned futility assessment was performed mid-study.

RESULTS

Dose compliance was 99%, blinding was intact, and no open-label agents were used. No treatment patient experienced dysrhythmia, myocardial infarction, or cardiac arrest. The study was stopped for futility after enrolling 47 patients (26 placebo, 21 treatment), per a priori stopping rules. There was no significant difference in VFDs between treatment and control groups [0.3 days, 95% CI (- 5.4, 5.8), p = 1.0]. Other than improvement of features related to sympathetic hyperactivity (mean difference in Clinical Features Scale (CFS) 1.7 points, CI (0.4, 2.9), p = 0.012), there were no between-group differences in the secondary outcomes.

CONCLUSION

Despite the safety and feasibility of adrenergic blockade with propranolol and clonidine after severe TBI, the intervention did not alter the VFD outcome. Given the widespread use of these agents in TBI care, a multi-center investigation is warranted to determine whether adrenergic blockade is of therapeutic benefit in patients with severe TBI. Trial Registration Number NCT01322048.

Propranolol Reduces p-tau Accumulation and Improves Behavior Outcomes in a Polytrauma Murine Model

INTRODUCTION

Traumatic brain injury (TBI) can lead to neurocognitive decline, in part due to phosphorylated tau (p-tau). Whether p-tau accumulation worsens in the setting of polytrauma remains unknown. Propranolol has shown clinical benefit in head injuries; however, the underlying mechanism is also unknown. We hypothesize that hemorrhagic shock would worsen p-tau accumulation but that propranolol would improve functional outcomes on behavioral studies.

METHODS

A murine polytrauma model was developed to examine the accumulation of p-tau and whether it can be mitigated by early administration of propranolol. TBI was induced using a weight-drop model and hemorrhagic shock was achieved via controlled hemorrhage for 1 h. Mice were given intraperitoneal propranolol 4 mg/kg or saline control. The animals underwent behavioral testing at 30 d postinjury and were sacrificed for cerebral histological analysis. These studies were completed in male and female mice.

RESULTS

TBI alone led to increased p-tau generation compared to sham on both immunohistochemistry and immunofluorescence (P < 0.05). The addition of hemorrhage led to greater accumulation of p-tau in the hippocampus (P < 0.007). In male mice, p-tau accumulation decreased with propranolol administration for both polytrauma and TBI alone (P < 0.0001). Male mice treated with propranolol also outperformed saline-control mice on the hippocampal-dependent behavioral assessment (P = 0.0013). These results were not replicated in female mice; the addition of hemorrhage did not increase p-tau accumulation and propranolol did not demonstrate a therapeutic effect.

CONCLUSIONS

Polytrauma including TBI generates high levels of hippocampal p-tau, but propranolol may help prevent this accumulation to improve both neuropathological and functional outcomes in males.

The Heart Is at Risk: Understanding Stroke-Heart-Brain Interactions with Focus on Neurogenic Stress Cardiomyopathy-A Review

In recent years, it has been convincingly demonstrated that acute brain injury may cause severe cardiac complications-such as neurogenic stress cardiomyopathy (NSC), a specific form of takotsubo cardiomyopathy. The pathophysiology of these brain-heart interactions is complex and involves sympathetic hyperactivity, activation of the hypothalamic-pituitary-adrenal axis, as well as immune and inflammatory pathways. There have been great strides in our understanding of the axis from the brain to the heart in patients with isolated acute brain injury and more specifically in patients with stroke. On the other hand, in patients with NSC, research has mainly focused on hemodynamic dysfunction due to arrhythmias, regional wall motion abnormality, or left ventricular hypokinesia that leads to impaired cerebral perfusion pressure. Comparatively little is known about the underlying secondary and delayed cerebral complications. The aim of the present review is to describe the stroke-heart-brain axis and highlight the main pathophysiological mechanisms leading to secondary and delayed cerebral injury in patients with concurrent hemorrhagic or ischemic stroke and NSC as well as to identify further areas of research that could potentially improve outcomes in this specific patient population.

MULTIMODAL TREATMENT APPROACHES TO COMBINED TRAUMATIC BRAIN INJURY AND HEMORRHAGIC SHOCK ALTER POSTINJURY INFLAMMATORY RESPONSE

ABSTRACT

Introduction: The optimal management strategies for patients with polytraumatic injuries that include traumatic brain injury (TBI) are not well defined. Specific interventions including tranexamic acid (TXA), propranolol, and hypertonic saline (HTS) have each demonstrated benefits in patient mortality after TBI, but have not been applied to TBI patients with concomitant hemorrhage. The goals of our study were to determine the inflammatory effects of resuscitation strategy using HTS or shed whole blood (WB) and evaluate the cerebral and systemic inflammatory effects of adjunct treatment with TXA and propranolol after combined TBI + hemorrhagic shock. Methods: Mice underwent TBI via weight drop and were subsequently randomized into six experimental groups: three with HTS resuscitation and three with WB resuscitation. Mice were then subjected to controlled hemorrhagic shock for 1 h to a goal MAP of 25 mmHg. Mice were then treated with an i.p. dose of 4 mg/kg propranolol, 100 mg/kg TXA, or normal saline (NS) as a control. Mice were killed at 1, 6, or 24 h for serum and cerebral biomarker evaluation by multiplex ELISA and serum neuron-specific enolase, a biomarker of cerebral cellular injury. Results: Mice resuscitated with HTS had elevated serum proinflammatory cytokines compared with WB resuscitated groups at 6 and 24 h after injury, with no significant difference in cerebral cytokine levels. Within the TBI/shock + HTS groups, the addition of propranolol or TXA did not significantly alter serum cytokine concentration, but cerebral IL-2, IL-12, and macrophage inflammatory protein-1α (MIP-1α) decreased after propranolol administration. In the TBI/shock + WB cohorts, the addition of both propranolol and TXA increased systemic proinflammatory cytokine levels at 6 and 24 h after injury as demonstrated by serum IL-2, IL-12, MIP-1α, and IL-1β compared with NS control. By contrast, TBI/shock + WB mice demonstrated a significant reduction in cerebral IL-2, IL-12, and MIP-1α in propranolol treated mice 6 h after injury compared with NS group. While serum neuron-specific enolase was significantly increased 1 and 24 h after injury in TBI/shock + HTS + TXA cohorts compared with NS control, it was significantly reduced in the TBI/shock + WB + propranolol mice compared with NS control 24 h after injury. Conclusions: Whole blood resuscitation can reduce the acute postinjury neuroinflammatory response after combined TBI/shock compared with HTS. The addition of either propranolol or TXA may modulate the postinjury systemic and cerebral inflammatory response with more improvements noted after propranolol administration. Multimodal treatment with resuscitation and pharmacologic therapy after TBI and hemorrhagic shock may mitigate the inflammatory response to these injuries to improve recovery.

Neurotrauma

PURPOSE OF REVIEW

This review will highlight the latest research relevant to the clinical care of traumatic brain injury (TBI) patients over the last 2 years while underscoring the implications of these advances in the understanding of diagnosis, treatment, and prognosis of TBI.

RECENT FINDINGS

Brain tissue oxygenation monitoring can identify hypoperfusion as an adjunct to intracerebral pressure monitoring. Multiple biomarker assays are now available to help clinicians screen for mild TBI and biomarker elevations correlate with the size of intracranial injury. Beta-blocker exposure following TBI has demonstrated a survival benefit in those with TBI though the mechanism for this remains unknown. The optimal timing for venous thromboembolism prophylaxis for TBI patients is still uncertain.

SUMMARY

The current characterization of TBI as mild, moderate, or severe fails to capture the complexity of the disease process and helps little with prognostication. Molecular biomarkers and invasive monitoring devices including brain tissue oxygenation and measures of cerebral autoregulation are being utilized more commonly and can help guide therapy. Extracranial complications following TBI are common and include infection, respiratory failure, coagulopathy, hypercoagulability, and paroxysmal sympathetic hyperactivity.

Postinjury Treatment to Mitigate the Effects of Aeromedical Evacuation After TBI in a Porcine Model

INTRODUCTION

Early aeromedical evacuation after traumatic brain injury (TBI) has been associated with worse neurologic outcomes in murine studies and military populations. The goal of this study was to determine if commonly utilized medications, including allopurinol, propranolol, or tranexamic acid (TXA), could mitigate the secondary traumatic brain injury experienced during the hypobaric and hypoxic environment of aeromedical evacuation.

METHODS

Porcine TBI was induced via controlled cortical injury. Twenty nonsurvival pigs were separated into four groups (n = 5 each): TBI+25 mL normal saline (NS), TBI+4 mg propranolol, TBI+100 mg allopurinol, and TBI+1g TXA. The pigs then underwent simulated AE to an altitude of 8000 ft for 4 h with an SpO₂ of 82-85% and were sacrificed 4 h later. Hemodynamics, serum cytokines, and hippocampal p-tau accumulation were assessed. An additional survival cohort was partially completed with TBI/NS (n = 5), TBI/propranolol (n = 2) and TBI/allopurinol groups (n = 2) survived to postinjury day 7.

RESULTS

There were no significant differences in hemodynamics, tissue oxygenation, cerebral blood flow, or physiologic markers between treatment groups and saline controls. Transient differences in IL-1b and IL-6 were noted but did not persist. Neurological Severity Score (NSS) was significantly lower in the TBI + allopurinol group on POD one compared to NS and propranolol groups. P-tau accumulation was decreased in the nonsurvival animals treated with allopurinol and TXA compared to the TBI/NS group.

CONCLUSIONS

Allopurinol, propranolol, and TXA, following TBI, do not induce adverse changes in systemic or cerebral hemodynamics during or after a simulated postinjury flight. While transient changes were noted in systemic cytokines and p-tau accumulation, further investigation will be needed to determine any persistent neurological effects of injury, flight, and pharmacologic treatment.

Beta-Blocker Therapy in Patients With Severe Traumatic Brain Injury: A Systematic Review and Meta-Analysis

INTRODUCTION

Traumatic brain injury (TBI), a leading cause of morbidity and mortality among trauma patients worldwide, poses the risk of secondary neurological insult due to significant catecholamine surge. We aim to investigate the effectiveness and outcomes of beta-blocker administration in patients with severe TBI.

METHODS

A search through PubMed, EMBASE, JAMA network, and Google Scholar databases was conducted for relevant peer-reviewed original studies published before February 15, 2022. A standard random-effects model was used, as justified by a high Cohen's Q test.

RESULTS

Twelve studies met inclusion criteria and were included in the meta-analysis. Severe TBI patients who were administered beta-blockers had a significantly reduced incidence of in-hospital mortality compared to the non-beta-blocker group (14.5% vs 19.2%). However, the beta-blocker group was reported to have a significantly greater number of ventilator days (5.58 vs 2.60 days). Similarly, intensive care unit (9.00 vs 6.84 days) and hospital (17.30 vs 11.02 days) lengths of stay (LOS) were increased in the beta-blocker group compared to those who were not administered beta-blocker therapy, but only the difference in hospital-LOS was significant.

CONCLUSIONS

Beta-blockers have significantly decreased in-hospital mortality in patients with severe TBI despite being associated with an increase in ventilator days and hospital-LOS. The administration of beta-blocker therapy in the management of severe TBI may be warranted and should be discussed in future guidelines.

Beta blockade in TBI: Dose-dependent reductions in BBB leukocyte mobilization and permeability in vivo

BACKGROUND

Traumatic brain injury (TBI) is accompanied by a hyperadrenergic catecholamine state that can cause penumbral neuroinflammation. Prospective human studies demonstrate improved TBI survival with beta blockade (bb), although mechanisms remain unclear. We hypothesized that deranged post-TBI penumbral blood brain barrier (BBB) leukocyte mobilization and permeability are improved by bb.

METHODS

CD1 male mice (n = 64) were randomly assigned to severe TBI-controlled cortical impact: 6 m/s velocity, 1 mm depth, 3 mm diameter-or sham craniotomy, and IP injection of either saline or propranolol (1, 2, or 4 mg/kg) every 12 hours for 2 days. At 48 hours, in vivo pial intravital microscopy visualized live endothelial-leukocyte (LEU) interactions and BBB microvascular leakage. Twice daily clinical recovery was assessed by regaining of lost body weight and the Garcia Neurological Test (motor, sensory, reflex, balance assessments). Brain edema was determined by hemispheric wet-to-dry ratios.

RESULTS

Propranolol after TBI reduced both in vivo LEU rolling and BBB permeability in a dose-dependent fashion compared with no treatment (p < 0.001). Propranolol reduced cerebral edema (p < 0.001) and hastened recovery of lost body weight at 48 hours (p < 0.01). Compared with no treatment (14.9 ± 0.2), 24-hour Garcia Neurologic Test scores were improved with 2 (15.8 ± 0.2, p = 0.02) and 4 (16.1 ± 0.1, p = 0.001) but not with 1 mg/kg propranolol.

CONCLUSION

Propranolol administration reduces post-TBI LEU mobilization and microvascular permeability in the murine penumbral neurovasculature and leads to reduced cerebral edema. This is associated with hastened recovery of post-TBI weight loss and neurologic function with bb treatment. Dose-dependent effects frame a mechanistic relationship between bb and improved human outcomes after TBI.

Pharmacological differences between beta-blockers and postoperative mortality following colon cancer surgery

β-blocker therapy has been positively associated with improved survival in patients undergoing oncologic colorectal resection. This study investigates if the type of β-blocker used affects 90-day postoperative mortality following colon cancer surgery. The study was designed as a nationwide retrospective cohort study including all adult (≥ 18 years old) patients with ongoing β-blocker therapy who underwent elective and emergency colon cancer surgery in Sweden between January 1, 2007 and December 31, 2017. Patients were divided into four cohorts: metoprolol, atenolol, bisoprolol, and other beta-blockers. The primary outcome of interest was 90-day postoperative mortality. A Poisson regression model with robust standard errors was used, while adjusting for all clinically relevant variables, to determine the association between different β-blockers and 90-day postoperative mortality. A total of 9254 patients were included in the study. There was no clinically significant difference in crude 90-day postoperative mortality rate [n (%)] when comparing the four beta-blocker cohorts metoprolol, atenolol, bisoprolol and other beta-blockers. [97 (1.8%) vs. 28 (2.0%) vs. 29 (1.7%) vs. 11 (1.2%), p = 0.670]. This remained unchanged when adjusting for relevant covariates in the Poisson regression model. Compared to metoprolol, there was no statistically significant decrease in the risk of 90-day postoperative mortality with atenolol [adj. IRR (95% CI): 1.45 (0.89–2.37), p = 0.132], bisoprolol [adj. IRR (95% CI): 1.45 (0.89–2.37), p = 0.132], or other beta-blockers [adj. IRR (95% CI): 0.92 (0.46–1.85), p = 0.825]. In patients undergoing colon cancer surgery, the risk of 90-day postoperative mortality does not differ between the investigated types of β-adrenergic blocking agents.

Beta blocker use in traumatic brain injury based on the high-sensitive troponin status (BBTBBT): methodology and protocol implementation of a double-blind randomized controlled clinical trial

Background

Beta-adrenergic receptor blockers (BB) play an important role in the protection of organs that are susceptible for secondary injury due to stress-induced adrenergic surge. However, the use of BB in traumatic brain injury (TBI) patients is not yet the standard of care which necessitates clear scientific evidence to be used. The BBTBBT study aims to determine whether early administration of propranolol based on the high-sensitive troponin T(HsTnT) status will improve the outcome of TBI patients. We hypothesized that early propranolol use is effective in reducing 10- and 30-day mortality in TBI patients. Secondary outcomes will include correlation between serum biomarkers (troponin, epinephrine, cytokines, enolase, S100 calcium binding protein B) and the severity of injury and the impact of BB use on the duration of hospital stay and functional status at a 3-month period.

Methods

The BBTBBT study is a prospective, randomized, double-blinded, placebo-controlled three-arm trial of BB use in mild-to-severe TBI patients based on the HsTnT status. All enrolled patients will be tested for HsTnT at the first 4 and 6 h post-injury. Patients with positive HsTnT will receive BB if there is no contraindication (group 1). Patients with negative HsTnT will be randomized to receive either propranolol (group 2) or placebo (group 3). The time widow for receiving the study treatment is the first 24 h post-injury.

Discussion

Early BB use may reduce the catecholamine storm and subsequently the cascade of immune and inflammatory changes associated with TBI. HsTnT could be a useful fast diagnostic and prognostic tool in TBI patients. This study will be of great clinical interest to improve survival and functional outcomes of TBI patients.

Trial registration

ClinicalTrials.gov NCT04508244. Registered on 7 August 2020. Recruitment started on 29 December 2020 and is ongoing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05872-8.

Mortality risk stratification in isolated severe traumatic brain injury using the revised cardiac risk index

PURPOSE

Traumatic brain injury (TBI) continues to be a significant cause of mortality and morbidity worldwide. As cardiovascular events are among the most common extracranial causes of death after a severe TBI, the Revised Cardiac Risk Index (RCRI) could potentially aid in the risk stratification of this patient population. This investigation aimed to determine the association between the RCRI and in-hospital deaths among isolated severe TBI patients.

METHODS

All adult patients registered in the TQIP database between 2013 and 2017 who suffered an isolated severe TBI, defined as a head AIS ≥ 3 with an AIS ≤ 1 in all other body regions, were included. Patients were excluded if they had a head AIS of 6. The association between different RCRI scores (0, 1, 2, 3, ≥ 4) and in-hospital mortality was analyzed using a Poisson regression model with robust standard errors while adjusting for potential confounders, with RCRI 0 as the reference.

RESULTS

259,399 patients met the study's inclusion criteria. RCRI 2 was associated with a 6% increase in mortality risk [adjusted IRR (95% CI) 1.06 (1.01-1.12), p = 0.027], RCRI 3 was associated with a 17% increased risk of mortality [adjusted IRR (95% CI) 1.17 (1.05-1.31), p = 0.004], and RCRI ≥ 4 was associated with a 46% increased risk of in-hospital mortality [adjusted IRR(95% CI) 1.46 (1.11-1.90), p = 0.006], compared to RCRI 0.

CONCLUSION

An elevated RCRI ≥ 2 is significantly associated with an increased risk of in-hospital mortality among patients with an isolated severe traumatic brain injury. The simplicity and bedside applicability of the index makes it an attractive choice for risk stratification in this patient population.

Early Antibiotic Administration is Independently Associated with Improved Survival in Traumatic Brain Injury

BACKGROUND

Central and systemic immune dysfunction after traumatic brain injury (TBI) can lead to infectious-related complications, which may result in delayed mortality. The role of early empiric antibiotics after TBI has not been characterized to date, but is recommended in select cases to decrease complications. We aimed to determine the relationship between early antibiotic use and in-hospital mortality in TBI patients.

METHODS

A retrospective review was conducted of TBI patients requiring ICU admission at an urban, academic, Level I trauma center from 01/2014 to 08/2016. Data collection included demographics, injury characteristics, details regarding antibiotic use, and outcomes. Early antibiotic administration was defined as any antibiotic given within 48 hs from admission. Patients given early antibiotics (EARLY) were compared to those who received their first dose later or did not receive any antibiotics (non-EARLY).

RESULTS

Of the 488 TBI patients meeting inclusion criteria, 189 (38.7%) received early antibiotics. EARLY patients were younger (EARLY 54.2 versus non-EARLY 61.5 ys, P <0.01) and more likely to be male (71.4% versus 60.9%, P = 0.02). Injury severity scores (23.6 versus 17.2, P <0.01) and regional head abbreviated injury scale scores (3.9 versus 3.7, P <0.01) were significantly higher in patients who received early antibiotics. Unadjusted in-hospital mortality rates were similar, however EARLY was associated with a lower mortality rate (AOR 0.17, 95% CI: 0.07 - 0.43, adjusted P <0.01) after adjusting for confounders.

CONCLUSIONS

Despite presenting with a higher injury burden, TBI patients who received early antibiotics had a lower associated mortality rate compared to their counterparts. Future investigations are necessary to understand the underlying mechanisms that result in this potential survival benefit.

Beta-Adrenergic Blockade in Critical Illness

Catecholamine upregulation is a core pathophysiological feature in critical illness. Sustained catecholamine β-adrenergic induction produces adverse effects relevant to critical illness management. β-blockers (βB) have proposed roles in various critically ill disease states, including sepsis, trauma, burns, and cardiac arrest. Mounting evidence suggests βB improve hemodynamic and metabolic parameters culminating in decreased burn healing time, reduced mortality in traumatic brain injury, and improved neurologic outcomes following cardiac arrest. In sepsis, βB appear hemodynamically benign after acute resuscitation and may augment cardiac function. The emergence of ultra-rapid βB provides new territory for βB, and early data suggest significant improvements in mitigating atrial fibrillation in persistently tachycardic septic patients. This review summarizes the evidence regarding the pharmacotherapeutic role of βB on relevant pathophysiology and clinical outcomes in various types of critical illness.

Early Propranolol Is Associated With Lower Risk of Venous Thromboembolism After Traumatic Brain Injury

BACKGROUND

Traumatic brain injury (TBI) results in an elaborate systemic cascade of secondary injury elicited in part by an intrinsic catecholamine response, which ultimately leads to changes in inflammation and coagulopathy. Attenuation of this catecholamine response with agents such as propranolol confers a survival advantage. The related impact of propranolol on venous thromboembolism (VTE) after TBI is largely unknown.

STUDY DESIGN

A single institution retrospective review was conducted of all TBI patients requiring intensive care unit (ICU) admission with an injury severity scale (ISS) ≥ 25 from January 2013 to May 2015. Patients who received at least one dose of propranolol within 24 hours of admission (PROP) were compared to patients who did not receive any doses of propranolol (NPROP) during their hospitalization.

RESULTS

Of the 131 patients analyzed, 31 (23.7%) patients received propranolol. The PROP cohort was more severely injured overall (ISS 29 vs 26.5, P = .02). While unadjusted VTE rates were similar (16.1% vs 19.0%, P = .72), the adjusted VTE rate was lower in the PROP cohort (AOR 0.20 (95% CI 0.04-0.97), adjusted P-value < .05).

CONCLUSION

Propranolol use in TBI patients who have sustained critical injuries may mitigate the risk of VTE. The mechanism by which this outcome is achieved requires further investigation.

Moderate and Severe Traumatic Brain Injury

PURPOSE OF REVIEW

Traumatic brain injury (TBI) encompasses a group of heterogeneous manifestations of a disease process with high neurologic morbidity and, for severe TBI, high probability of mortality and poor neurologic outcomes. This article reviews TBI in neurocritical care, hence focusing on moderate and severe TBI, and includes an up-to-date review of the many variables to be considered in clinical care.

RECENT FINDINGS

With advances in medicine and biotechnology, understanding of the impact of TBI has substantially elucidated the distinction between primary and secondary brain injury. Consequently, care of TBI is evolving, with intervention-based modalities targeting multiple physiologic variables. Multimodality monitoring to assess intracranial pressure, cerebral oxygenation, cerebral metabolism, cerebral blood flow, and autoregulation is at the forefront of such advances.

SUMMARY

Understanding the anatomic and physiologic principles of acute brain injury is necessary in managing moderate to severe TBI. Management is based on the prevention of secondary brain injury from resultant trauma. Care of patients with TBI should occur in a dedicated critical care unit with subspecialty expertise. With the advent of multimodality monitoring and targeted biomarkers in TBI, patient outcomes have a higher probability of improving in the future.

Post-traumatic brain injury antithrombin III recovers Morris water maze cognitive performance, improving cued and spatial learning

BACKGROUND

Neuroinflammation and cerebral edema development following severe traumatic brain injury (TBI) affect subsequent cognitive recovery. Independent of its anticoagulant effects, antithrombin III (AT-III) has been shown to block neurovascular inflammation after severe TBI, reduce cerebral endothelial-leukocyte interactions, and decrease blood-brain barrier permeability. We hypothesized that AT-III administration after TBI would improve post-TBI cognitive recovery, specifically enhancing learning, and memory.

METHODS

Fifteen CD1 male mice were randomized to undergo severe TBI (controlled cortical impact [CCI]: velocity, 6 m/s; depth, 1 mm; diameter, 3 mm) or sham craniotomy and received either intravenous AT-III (250 IU/kg) or vehicle (VEH/saline) 15 minutes and 24 hours post-TBI. Animals underwent Morris water maze testing from 6 to 14 days postinjury consisting of cued learning trials (platform visible), spatial learning trials (platform invisible, spatial cues present), and probe (memory) trials (platform removed, spatial cues present). Intergroup differences were assessed by the Kruskal-Wallis test (p < 0.05).

RESULTS

Morris water maze testing demonstrated that cumulative cued learning (overall mean time in seconds to reach the platform on days 6-8) was worst in CCI-VEH animals (26.1 ± 2.4 seconds) compared with CCI-AT-III counterparts (20.3 ± 2.1 seconds, p < 0.01). Cumulative noncued spatial learning was also worst in the CCI-VEH group (23.4 ± 1.8 seconds) but improved with AT-III (17.6 ± 1.5 seconds, p < 0.01). In probe trials, AT-III failed to significantly improve memory ability. Animals that underwent sham craniotomy demonstrated preserved learning and memory compared with all CCI counterparts (p < 0.05).

CONCLUSION

Antithrombin III improves neurocognitive recovery weeks after TBI. This improvement is particularly related to improvement in learning but not memory function. Pharmacologic support of enhanced learning may support new skill acquisition or relearning to improve outcomes after TBI.

LEVEL OF EVIDENCE

Therapeutic/care management, level II.

β-Blockers for traumatic brain injury: A systematic review and meta-analysis

BACKGROUND

Paroxysmal sympathetic hyperactivity (PSH) and catecholamine surge, which are associated with poor outcome, may be triggered by traumatic brain injury (TBI).β Adrenergic receptor blockers (β-blockers), as potential therapeutic agents to prevent paroxysmal sympathetic hyperactivity and catecholamine surge, have been shown to improve survival after TBI. The principal aim of this study was to investigate the effect of β-blockers on outcomes in patients with TBI.

METHODS

For this systematic review and meta-analysis, we searched MEDLINE, EMBASE, and Cochrane Library databases from inception to September 25, 2020, for randomized controlled trials, nonrandomized controlled trials, and observational studies reporting the effect of β-blockers on the following outcomes after TBI: mortality, functional measures, and cardiopulmonary adverse effects of β-blockers (e.g., hypotension, bradycardia, and bronchospasm). With use of random-effects model, we calculated pooled estimates, confidence intervals (CIs), and odds ratios (ORs) of all outcomes.

RESULTS

Fifteen studies with 12,721 patients were included. Exposure to β-blockers after TBI was associated with a significant reduction in adjusted in-hospital mortality (OR, 0.39; 95% CI, 0.30-0.51; I2 = 66.3%; p < 0.001). β-Blockers significantly improved the long-term (≥6 months) functional outcome (OR, 1.75; 95% CI, 1.09-2.80; I2 = 0%; p = 0.02). Statistically significant difference was not seen for cardiopulmonary adverse events (OR, 0.91; 95% CI, 0.55-1.50; I2 = 25.9%; p = 0.702).

CONCLUSION

This meta-analysis demonstrated that administration of β-blockers after TBI was safe and effective. Administration of β-blockers may therefore be suggested in the TBI care. However, more high-quality trials are needed to investigate the use of β-blockers in the management of TBI.

LEVEL OF EVIDENCE

Systematic review and meta-analysis, level III.

Mitigating the stress response to improve outcomes for older patients undergoing emergency surgery with the addition of beta-adrenergic blockade

As population age, healthcare systems and providers are likely to experience a substantial increase in the proportion of elderly patients requiring emergency surgery. Emergency surgery, compared with planned surgery, is strongly associated with increased risks of adverse postoperative outcomes due to the short time available for diagnosis, optimization, and intervention in patients presenting with physiological derangement. These patient populations, who are often frail and burdened with a variety of co-morbidities, have lower reserves to deal with the stress of the acute condition and the required emergency surgical intervention. In this review article, we discuss topical areas where mitigation of the physiological stress posed by the acute condition and asociated surgical intervention may be feasible. We consider the impact of the adrenergic response and use of beta blockers for these high-risk patients and discuss common risk factors such as frailty and delirium. A proactive multidisciplinary approach to peri-operative care aimed at mitigation of the stress response and proactive management of common conditions in the older emergency surgical patient could yield more favorable outcomes.

A Systematic Review and Meta-Analysis on Effect of Beta-Blockers in Severe Traumatic Brain Injury

OBJECTIVES

Systematically review the medical literature for the impact of beta-blockers on mortality and functional capacity in patients who suffered severe traumatic brain injury.

DATA SOURCES

The search included MEDLINE, EMBASE, and Ovid Evidence-Based Medicine, clinical trial registries, and bibliographies.

STUDY SELECTION

All articles that reported outcome in TBI patients treated with beta-blockers.

DATA EXTRACTION

Publication year, number of patients, outcome and follow-up. We performed a meta-analysis for each variable for which there were sufficient data to estimate mean differences.

DATA SYNTHESIS

12 studies were included, which involved retrospectively and prospectively collected data on 14,057 patients. The treatment with beta-blockers was associated with a reduction in mortality in patients who were treated with beta-blockers compared to the control group (OR 0.40, 95% CI 0.30-0.54p = <0.00001), with acceptable heterogeneity between studies (I2 = 65% p = 0.00008). Beta-blocker therapy decreases the risk of negative neurological and functional outcomes (OR 0.59, 95% CI 0.38-0.92 p = <0.00001), a very high statistical heterogeneity between the included studies (I2 = 80% p = 0.00004), being able to influence the results. An increase in favorable neurological and functional outcomes is shown (OR 1.19, 95% CI 1.07-1.31 p = 0.001) with acceptable heterogeneity (I2 = 52% p = 0.08).

CONCLUSIONS

The beta-blockers therapy is associated with significantly improves outcome in patients with TBI. Treatment with beta-blockers in patients with TBI is a promising frontier in neurotrauma.

ABBREVIATIONS

CI: confidence interval; BB: Beta-Blockers; OR = odds ratio; TBI: Traumatic Brain Injury SD: Standard deviation; SNS: Sympathetic nervous system.

Drug Use in Pediatric Patients Admitted to Rehabilitation For Severe Acquired Brain Injury: Analysis of the Associations With Rehabilitation Outcomes

INTRODUCTION

Patients with severe acquired brain injuries require drug therapies in intensive care for life support and injury treatment. Patients who then access rehabilitation usually maintain their drug treatments long term, with a potential influence on the rehabilitation course. Whereas drug effects have been reported for specific drugs and clinical issues in adults, comprehensive data on pediatric patients with traumatic and non-traumatic injuries are scant.

OBJECTIVES

The aims of this study were to describe the therapeutic classes and groups of drugs prescribed to pediatric inpatients recovering from severe acquired brain injury when they enter rehabilitation; to assess whether clinical variables may determine the use of drug classes; and to assess whether the use of drug classes may be associated with differences in rehabilitation outcomes.

METHODS

We carried out a retrospective chart review, following a previous study on the clinical-epidemiological characteristics of our patients. We collected information on drug therapies present at admittance to rehabilitation and analyzed their distribution according to therapeutic classes and groups. We verified the associations of drug groups with clinical variables (putatively antecedents to drug use) and with rehabilitation outcomes (putatively resultant of drug use and of clinical variables) in regression models. The clinical variables considered were injury etiology, Glasgow Outcome Score (GOS) at admittance to rehabilitation, sex, age at injury, plus two aggregate factors resulting from the previous work, 'neurological dysfunction' regarding the use of devices and 'injury severity' regarding the neurological status. The rehabilitation outcomes used were death after rehabilitation, persistence of a vegetative/minimally conscious state, coma duration, duration of the rehabilitation stay, rehabilitation efficiency (GOS at discharge minus GOS at admittance, divided by the length of rehabilitation stay).

RESULTS

We described the distribution of drug classes and groups among pediatric patients with severe acquired brain injuries. Regarding the associations between drug classes and clinical variables, we found greater use of cardiovascular agents with higher patient age, 'neurological dysfunction' score, and with an etiology of hypoxic brain injury. The use of antithrombotic agents was greater with higher patient age and 'neurological dysfunction' score. Glucocorticoid use was greater with higher GOS at admittance and with several etiologies: brain tumor, infective encephalitis, and autoimmune encephalitis. Regarding drug classes and rehabilitation outcomes, we found that the use of cardiovascular drugs was associated with increased occurrence of death after rehabilitation. The use of antispastic drugs was associated with a more frequent permanence in vegetative/minimally conscious states. The use of antispastic drugs and melatonin was associated with longer coma duration. The use of glucocorticoid drugs was associated with decreased rehabilitation efficiency.

CONCLUSIONS

We provided a description of drug use in pediatric rehabilitation after severe acquired brain injuries, which was lacking in the literature. Prospective studies should verify our associative observations regarding clinical variables, drugs use, and outcomes, to assess causality.

Use of Thoracic Endovascular Aortic Repair in Patients with Concomitant Blunt Aortic and Traumatic Brain Injury

BACKGROUND

Blunt aortic injury (BAI) and traumatic brain injury (TBI) represent the 2 leading causes of death after blunt trauma. The goal of this study was to examine the impact of TBI and use of thoracic endovascular aortic repair (TEVAR) on patients with BAI, using a large, national dataset.

STUDY DESIGN

Patients with BAI were identified from the Trauma Quality Improvement Program (TQIP) database over 10 years, ending in 2016. Patients with BAI were stratified by the presence of concomitant TBI and compared. Multivariable logistic regression (MLR) analysis was performed to determine independent predictors of mortality in BAI patients with and without TBI. Youden's index was used to identify the optimal time to TEVAR in these patients.

RESULTS

17,040 patients with BAI were identified, with 4,748 (28%) having a TBI. Patients with BAI and TBI were predominantly male, with a higher injury burden and greater severity of shock at presentation, underwent fewer TEVAR procedures, and had increased mortality compared with BAI patients without TBI. The optimal time for TEVAR was 9 hours. Mortality was significantly increased in patients undergoing TEVAR before 9 hours (12.9% vs 6.5%, p = 0.003). For BAI patients with and without TBI, MLR identified use of TEVAR as the only modifiable risk factor significantly associated with reduced mortality (odds ratio [OR] 0.41; 95%CI 0.32-0.54, p < 0.0001).

CONCLUSIONS

TBI significantly increases mortality in BAI patients. TEVAR and delayed repair both significantly reduced mortality. So, for patients with both BAI and TBI, an endovascular repair performed in a delayed fashion should be the preferred approach.

Autonomic Hyperactivity

PURPOSE OF REVIEW

Autonomic hyperactivity is a relatively common consequence of severe acute brain injury and can also be seen with spinal cord and peripheral nerve disorders. This article reviews basic pathophysiologic concepts regarding autonomic hyperactivity, its various forms of clinical presentation, and practical management considerations.

RECENT FINDINGS

Paroxysmal sympathetic hyperactivity is most common after traumatic brain injury but can also occur after other forms of severe acute diffuse or multifocal brain injury. Formal criteria for the diagnosis and severity grading of paroxysmal sympathetic hyperactivity have now been proposed. A growing body of literature is beginning to elucidate the mechanisms underlying this disorder, but treatment remains based on observational data. Our mechanistic understanding of other distinct forms of autonomic hyperactivity, such as autonomic dysreflexia after traumatic spinal cord injury and dysautonomia after Guillain-Barré syndrome, remains rudimentary, yet clinical experience shows that their appropriate management can minimize the risk of serious complications.

SUMMARY

Syndromes of autonomic hyperactivity can result from injury at all levels of the neuraxis. Much more research is needed to refine our understanding of these disorders and guide optimal management decisions.

Organic features of autonomic dysregulation in paediatric brain injury - Clinical and research implications for the management of patients with Rett syndrome

Rett Syndrome (RTT) is a complex neurodevelopmental disorder with autonomic nervous system dysfunction. The understanding of this autonomic dysregulation remains incomplete and treatment recommendations are lacking. By searching literature regarding childhood brain injury, we wanted to see whether understanding autonomic dysregulation following childhood brain injury as a prototype can help us better understand the autonomic dysregulation in RTT. Thirty-one (31) articles were identified and following thematic analysis the three main themes that emerged were (A) Recognition of Autonomic Dysregulation, (B) Possible Mechanisms & Assessment of Autonomic Dysregulation and (C) Treatment of Autonomic Dysregulation. We conclude that in patients with RTT (I) anatomically, thalamic and hypothalamic function should be explored, (II) sensory issues and medication induced side effects that can worsen autonomic function should be considered, and (III) diaphoresis and dystonia ought to be better managed. Our synthesis of data from autonomic dysregulation in paediatric brain injury has led to increased knowledge and a better understanding of its underpinnings, leading to the development of application protocols in children with RTT.

Long-Term Analysis of Functional Outcomes in Traumatic Brain Injury Patients

INTRODUCTION

Traumatic brain injury (TBI) remains a significant cause of morbidity and mortality. The purpose of this study is to examine outcomes after discharge and identify factors from the index admission that may contribute to long-term mortality.

METHODS

The study population is composed of patients who survived to discharge from a previously published study examining TBI. Demographics, injury severity, and length of stay were abstracted from the index study. Phone surveys of surviving patients were performed to evaluate each patient's Glasgow Outcome Scale-Extended (GOSE). Patients who were deceased at the time of the survey were compared with those who were alive.

RESULTS

1615 patients were alive at the end of the first study period and 211 (13%) comprised the study population. Overall, the median age was 54 years, and the majority were male (74%). The median time to follow-up was 80 months. The population was severely injured, with a median injury severity score (ISS) of 25 and a median head abbreviated injury score (AIS) of 4. Overall mortality was 57%. The group that survived at the time of the survey was younger, more injured, less likely to have received beta-blockers (BB) during the index admission, and had a longer time to follow-up. After adjusting for ISS, age, base deficit, and BB, age was the only variable predictive of mortality (HR 1.03; HL 1.02-1.04).

CONCLUSION

Despite being more severely injured, younger patients were more likely to survive to follow-up. Further investigation is needed to determine if aggressive care in older TBI patients in the acute phase leads to good long-term outcomes.

Crosstalk between brain, lung and heart in critical care

Extracerebral complications, especially pulmonary and cardiovascular, are frequent in brain-injured patients and are major outcome determinants. Two major pathways have been described: brain-lung and brain-heart interactions. Lung injuries after acute brain damages include ventilator-associated pneumonia (VAP), acute respiratory distress syndrome (ARDS) and neurogenic pulmonary œdema (NPE), whereas heart injuries can range from cardiac enzymes release, ECG abnormalities to left ventricle dysfunction or cardiogenic shock. The pathophysiologies of these brain-lung and brain-heart crosstalk are complex and sometimes interconnected. This review aims to describe the epidemiology and pathophysiology of lung and heart injuries in brain-injured patients with the different pathways implicated and the clinical implications for critical care physicians.

Propranolol attenuates cognitive, learning, and memory deficits in a murine model of traumatic brain injury

BACKGROUND

β-blockers have been shown to improve survival after traumatic brain injury (TBI); however, the impact of continuous dosage of β-blockers on cognitive function has not been elucidated. We hypothesized that a daily dose of propranolol can improve memory, learning, and cognitive function following TBI.

STUDY DESIGN

Twenty male C57BL mice were subjected to a cortical-controlled moderate TBI. Two hours after TBI, animals were randomly allocated to either the β-blocker group (n = 10) or the placebo group (n = 10). Mice in the β-blocker group received intraperitoneal 4 mg/kg propranolol every 24 hours for 7 days while the placebo group received 4 mg/kg normal saline. Baseline novel object recognition and classic maze tests were done prior to TBI and then daily from Day 1 through 7 after TBI. Animals were sacrificed on Day 7. Serum biomarkers were measured using ELISA and brain sections were analyzed using western blot and hematoxylin and eosin staining.

RESULTS

Both the β-blocker and placebo groups had lower recognition index scores compared with the baseline following TBI. β-blocker mice had significantly higher novel object recognition scores compared with placebo mice 2 days after TBI. The β-blocker group required less time to complete the maze-test compared to placebo group after Day 4. There was no difference regarding the serum levels of IL-1β, IL-6, and TNF-α. The β-blocker group had lower levels of UCHL-1 and higher levels of Hsp-70 in brain lysate. Hematoxylin and eosin staining revealed that more neurons in the hippocampal-CA1 area underwent apoptosis in the placebo group compared with the β-blocker group.

CONCLUSION

Postinjury propranolol administration results in improved memory, learning and cognitive functions in a murine model of moderate TBI. Propranolol increases the expression of antiapoptotic protein (Hsp-70) and decreases cell death in the hippocampal-CA1 area compared with the placebo.

Beta-Blocker Therapy in Severe Traumatic Brain Injury: A Prospective Randomized Controlled Trial

Background

Observational studies have demonstrated improved outcomes in TBI patients receiving in-hospital beta-blockers. The aim of this study is to conduct a randomized controlled trial examining the effect of beta-blockers on outcomes in TBI patients.

Methods

Adult patients with severe TBI (intracranial AIS ≥ 3) were included in the study. Hemodynamically stable patients at 24 h after injury were randomized to receive either 20 mg propranolol orally every 12 h up to 10 days or until discharge (BB+) or no propranolol (BB−). Outcomes of interest were in-hospital mortality and Glasgow Outcome Scale-Extended (GOS-E) score on discharge and at 6-month follow-up. Subgroup analysis including only isolated severe TBI (intracranial AIS ≥ 3 with extracranial AIS ≤ 2) was carried out. Poisson regression models were used.

Results

Two hundred nineteen randomized patients of whom 45% received BB were analyzed. There were no significant demographic or clinical differences between BB+ and BB− cohorts. No significant difference in in-hospital mortality (adj. IRR 0.6 [95% CI 0.3–1.4], p = 0.2) or long-term functional outcome was measured between the cohorts (p = 0.3). One hundred fifty-four patients suffered isolated severe TBI of whom 44% received BB. The BB+ group had significantly lower mortality relative to the BB− group (18.6% vs. 4.4%, p = 0.012). On regression analysis, propranolol had a significant protective effect on in-hospital mortality (adj. IRR 0.32, p = 0.04) and functional outcome at 6-month follow-up (GOS-E ≥ 5 adj. IRR 1.2, p = 0.02).

Conclusion

Propranolol decreases in-hospital mortality and improves long-term functional outcome in isolated severe TBI. This randomized trial speaks in favor of routine administration of beta-blocker therapy as part of a standardized neurointensive care protocol.

Level of evidence

Level II; therapeutic.

Study type

Therapeutic study.