Beta-blocker exposure in patients with severe traumatic brain injury (TBI) and cardiac uncoupling

Effects of early propranolol administration on mortality from severe, traumatic brain injury: a retrospective propensity score-matched registry study

BACKGROUND

The role of beta-blockers in severe, traumatic brain injury (TBI) management is debated. Severe TBI may elicit a surge of catecholamines, which has been associated with increased morbidity and mortality. We hypothesize administering propranolol, a non-selective beta-blocker, within 48 h of TBI will reduce patient mortality within 30 days of injury. The TriNetX database was leveraged to determine if administering a propranolol within 48 h of severe TBI improves outcomes within 30 days of injury.

METHODS

The TriNetX Research Network was used to form two cohorts using retrospective data from 106,294,356 patient profiles from 9/10/2022, which included patients from years 2022 to 2022. The propranolol-receiving cohort included all patients who received the first-instance diagnosis of severe TBI (defined by a Glascow coma scale score of 3-8) and propranolol within 48 h of injury. The non-propranolol-receiving cohort included all patients with the same diagnosis of severe TBI but did not receive beta-blockers. The primary outcome of interest was mortality at 30 days. Secondary outcomes included gastrostomy tube placement, neurosurgical intervention in the form of craniotomy, craniectomy, burr hole drainage, seizure, and cardiac arrest.

RESULTS

After propensity score-matching, 381 patients were identified for both cohorts. At 30 days post-severe TBI, 22.7% (84) of patients from the cohort that received propranolol, and 30.77% (116) from the cohort that did not, were deceased (OR 0.66), 95% CI [0.48, 0.92]), (p 0.01). TBI patients who received propranolol also had lower odds of requiring neurosurgical intervention, experience seizures, and cardiac arrest.

CONCLUSION

The results of this study demonstrate significantly reduced mortality within 30 days of injury and fewer neurosurgical interventions, seizures, and episodes of cardiac arrest in severe TBI patients who received propranolol within 48 h of injury.

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.

Current Clinical Trials in Traumatic Brain Injury

Traumatic brain injury (TBI) is one of the leading causes of morbidity, disability and mortality across all age groups globally. Currently, only palliative treatments exist, but these are suboptimal and do little to combat the progressive damage to the brain that occurs after a TBI. However, multiple experimental treatments are currently available that target the primary and secondary biochemical and cellular changes that occur after a TBI. Some of these drugs have progressed to clinical trials and are currently being evaluated for their therapeutic benefits in TBI patients. The aim of this study was to identify which drugs are currently being evaluated in clinical trials for TBI. A search of ClinicalTrials.gov was performed on 3 December 2021 and all clinical trials that mentioned “TBI” OR “traumatic brain injury” AND “drug” were searched, revealing 362 registered trials. Of the trials, 46 were excluded due to the drug not being mentioned, leaving 138 that were completed and 116 that were withdrawn. Although the studies included 267,298 TBI patients, the average number of patients per study was 865 with a range of 5–200,000. Of the completed studies, 125 different drugs were tested in TBI patients but only 7 drugs were used in more than three studies, including amantadine, botulinum toxin A and tranexamic acid (TXA). However, previous clinical studies using these seven drugs showed variable results. The current study concludes that clinical trials in TBI have to be carefully conducted so as to reduce variability across studies, since the severity of TBI and timing of therapeutic interventions were key aspects of trial success.

Management and Challenges of Severe Traumatic Brain Injury

Traumatic brain injury (TBI) is the leading cause of death and disability in trauma patients, and can be classified into mild, moderate, and severe by the Glasgow coma scale (GCS). Prehospital, initial emergency department, and subsequent intensive care unit (ICU) management of severe TBI should focus on avoiding secondary brain injury from hypotension and hypoxia, with appropriate reversal of anticoagulation and surgical evacuation of mass lesions as indicated. Utilizing principles based on the Monro-Kellie doctrine and cerebral perfusion pressure (CPP), a surrogate for cerebral blood flow (CBF) should be maintained by optimizing mean arterial pressure (MAP), through fluids and vasopressors, and/or decreasing intracranial pressure (ICP), through bedside maneuvers, sedation, hyperosmolar therapy, cerebrospinal fluid (CSF) drainage, and, in refractory cases, barbiturate coma or decompressive craniectomy (DC). While controversial, direct ICP monitoring, in conjunction with clinical examination and imaging as indicated, should help guide severe TBI therapy, although new modalities, such as brain tissue oxygen (PbtO₂) monitoring, show great promise in providing strategies to optimize CBF. Optimization of the acute care of severe TBI should include recognition and treatment of paroxysmal sympathetic hyperactivity (PSH), early seizure prophylaxis, venous thromboembolism (VTE) prophylaxis, and nutrition optimization. Despite this, severe TBI remains a devastating injury and palliative care principles should be applied early. To better affect the challenging long-term outcomes of severe TBI, more and continued high quality research is required.

Propranolol protects cerebral autoregulation and reduces hippocampal neuronal cell death through inhibition of interleukin-6 upregulation after traumatic brain injury in pigs

BACKGROUND

Traumatic brain injury (TBI) is associated with reduced cerebral blood flow and impaired autoregulation after TBI, which may lead to poor outcome. Clinical evidence has implicated neurological injuries and associated neuroinflammation as causes of cardiac dysfunction. Studies on newborn pigs show an association of elevated catecholamines with a sex-dependent impairment of cerebral autoregulation after TBI. One strategy to decrease sympathetic hyperactivity is pharmacological intervention with beta blockade. We tested the hypothesis that propranolol would prevent the impairment of cerebral autoregulation and tissue changes after TBI via inhibition of interleukin-6 (IL-6) upregulation.

METHODS

Using newborn pigs of both sexes equipped with a closed cranial window, TBI was induced via lateral fluid percussion injury. Propranolol was administered at 1 h post-TBI. Analyses included cerebral autoregulation (pial artery reactivity) before and 4 h post-TBI, CSF IL-6 analysed (enzyme-linked immunosorbent assay), and histopathology at 4 h post-TBI.

RESULTS

Propranolol administration prevented impairment of hypotensive dilation in both male and female newborn pigs after fluid percussion injury, which was paralleled by reduced upregulation of IL-6 in the CSF. Moreover, propranolol prevented neuronal cell death in cornu amonis (CA)1 and CA3 hippocampus equivalently in male and female pigs after TBI. Papaverine-induced dilation was unchanged by TBI and propranolol.

CONCLUSIONS

These data indicate that sympathetic hyperactivity noted after TBI can be limited by propranolol administration to result in improved brain outcome post-injury via block of IL-6 upregulation, and this effect is irrespective of sex.

Beta-adrenergic blockade for attenuation of catecholamine surge after traumatic brain injury: a randomized pilot trial

Background

Beta-blockers have been proven in multiple studies to be beneficial in patients with traumatic brain injury. Few prospective studies have verified this and no randomized controlled trials. Additionally, most studies do not titrate the dose of beta-blockers to therapeutic effect. We hypothesize that propranolol titrated to effect will confer a survival benefit in patients with traumatic brain injury.

Methods

A randomized controlled pilot trial was performed during a 24-month period. Patients with traumatic brain injury were randomized to propranolol or control group for a 14-day study period. Variables collected included demographics, injury severity, physiologic parameters, urinary catecholamines, and outcomes. Patients receiving propranolol were compared with the control group.

Results

Over the study period, 525 patients were screened, 26 were randomized, and 25 were analyzed. Overall, the mean age was 51.3 years and the majority were male with blunt mechanism. The mean Injury Severity Score was 21.8 and median head Abbreviated Injury Scale score was 4. Overall mortality was 20.0%. Mean arterial pressure was higher in the treatment arm as compared with control (p=0.021), but no other differences were found between the groups in demographics, severity of injury, severity of illness, physiologic parameters, or mortality (7.7% vs. 33%; p=0.109). No difference was detected over time in any variables with respect to treatment, urinary catecholamines, or physiologic parameters. Glasgow Coma Scale (GCS), Sequential Organ Failure Assessment, and Acute Physiology and Chronic Health Evaluation scores all improved over time. GCS at study end was significantly higher in the treatment arm (11.7 vs. 8.9; p=0.044). Finally, no difference was detected with survival analysis over time between groups.

Conclusions

Despite not being powered to show statistical differences between groups, GCS at study end was significantly improved in the treatment arm and mortality was improved although not at a traditional level of significance. The study protocol was safe and feasible to apply to an appropriately powered larger multicenter study.

Level of evidence

Level 2—therapeutic.

Neuroprotective Agents in the Intensive Care Unit: -Neuroprotective Agents in ICU

Neuroprotection or prevention of neuronal loss is a complicated molecular process that is mediated by various cellular pathways. Use of different pharmacological agents as neuroprotectants has been reported especially in the last decades. These neuroprotective agents act through inhibition of inflammatory processes and apoptosis, attenuation of oxidative stress and reduction of free radicals. Control of this injurious molecular process is essential to the reduction of neuronal injuries and is associated with improved functional outcomes and recovery of the patients admitted to the intensive care unit. This study reviews neuroprotective agents and their mechanisms of action against central nervous system damages.

Brain-Heart Interactions in Traumatic Brain Injury

The cardiovascular manifestations associated with nontraumatic head disorders are commonly known. Similar manifestations have been reported in patients with traumatic brain injury (TBI); however, the underlying mechanisms and impact on the patient's clinical outcomes are not well explored. The neurocardiac axis theory and neurogenic stunned myocardium phenomenon could partly explain the brain-heart link and interactions and can thus pave the way to a better understanding and management of TBI. Several observational retrospective studies have shown a promising role for beta-adrenergic blockers in patients with TBI in reducing the overall TBI-related mortality. However, several questions remain to be answered in clinical randomized-controlled trials, including population selection, beta blocker type, dosage, timing, and duration of therapy, while maintaining the optimal mean arterial pressure and cerebral perfusion pressure in patients with TBI.

β-Blockade use for Traumatic Injuries and Immunomodulation: A Review of Proposed Mechanisms and Clinical Evidence

Sympathetic nervous system activation and catecholamine release are important events following injury and infection. The nature and timing of different pathophysiologic insults have significant effects on adrenergic pathways, inflammatory mediators, and the host response. Beta adrenergic receptor blockers (β-blockers) are commonly used for treatment of cardiovascular disease, and recent data suggests that the metabolic and immunomodulatory effects of β-blockers can expand their use. β-blocker therapy can reduce sympathetic activation and hypermetabolism as well as modify glucose homeostasis and cytokine expression. It is the purpose of this review to examine either the biologic basis for proposed mechanisms or to describe current available clinical evidence for the use of β-blockers in traumatic brain injury, spinal cord injury, hemorrhagic shock, acute traumatic coagulopathy, erythropoietic dysfunction, metabolic dysfunction, pulmonary dysfunction, burns, immunomodulation, and sepsis.

Beta-blockers and Traumatic Brain Injury: A Systematic Review, Meta-analysis, and Eastern Association for the Surgery of Trauma Guideline

OBJECTIVE

To determine if beta-(β)-blockers improve outcomes after acute traumatic brain injury (TBI).

BACKGROUND

There have been no new inpatient pharmacologic therapies to improve TBI outcomes in a half-century. Treatment of TBI patients with β-blockers offers a potentially beneficial approach.

METHODS

Using MEDLINE, EMBASE, and CENTRAL databases, eligible articles for our systematic review and meta-analysis (PROSPERO CRD42016048547) included adult (age ≥ 16 years) blunt trauma patients admitted with TBI. The exposure of interest was β-blocker administration initiated during the hospitalization. Outcomes were mortality, functional measures, quality of life, cardiopulmonary morbidity (e.g., hypotension, bradycardia, bronchospasm, and/or congestive heart failure). Data were analyzed using a random-effects model, and represented by pooled odds ratio (OR) with 95% confidence intervals (CI) and statistical heterogeneity (I).

RESULTS

Data were extracted from 9 included studies encompassing 2005 unique TBI patients with β-blocker treatment and 6240 unique controls. Exposure to β-blockers after TBI was associated with a reduction of in-hospital mortality (pooled OR 0.39, 95% CI: 0.27-0.56; I = 65%, P < 0.00001). None of the included studies examined functional outcome or quality of life measures, and cardiopulmonary adverse events were rarely reported. No clear evidence of reporting bias was identified.

CONCLUSIONS

In adults with acute TBI, observational studies reveal a significant mortality advantage with β-blockers; however, quality of evidence is very low. We conditionally recommend the use of in-hospital β-blockers. However, we recommend further high-quality trials to answer questions about the mechanisms of action, effectiveness on subgroups, dose-response, length of therapy, functional outcome, and quality of life after β-blocker use for TBI.

Therapeutic effect of beta-blocker in patients with traumatic brain injury: A systematic review and meta-analysis

OBJECTIVE

β-Blocker exposure has been shown to reduce mortality in traumatic brain injury (TBI); however, the efficacy of β-blockers remains inconclusive. Therefore, a meta-analysis was conducted in this paper to evaluate the safety and efficacy of β-blocker therapy on patients with TBI.

METHODS

The electronic databases were systemically retrieved from construction to February 2017. The odds ratio (OR), mean difference (MD) and 95% confidence intervals (CI) were determined.

RESULTS

A total of 13 observational cohort studies involving 15,734 cases were enrolled. The results indicated that β-blocker therapy had remarkably reduced the in-hospital mortality (OR 0.33; 95% CI 0.27-0.40; p<0.001). However, β-blocker therapy was also associated with increased infection rate (OR 2.01; 95% CI 1.50-2.69; p<0.001), longer length of stay (MD=7.40; 95% CI=4.39, 10.41; p<0.001) and ICU stay (MD=3.52; 95% CI=1.56, 5.47; p<0.001). In addition, β-blocker therapy also led to longer period of ventilator support (MD=2.70; 95% CI=1.81, 3.59; p<0.001).

CONCLUSION

The meta-analysis demonstrates that β-blockers are effective in lowering mortality in patients with TBI. However, β-blocker therapy has markedly increased the infection rate and requires a longer period of ventilator support, intensive care management as well as length of stay.

An Analysis of Beta-Blocker Administration Pre-and Post-Traumatic Brain Injury with Subanalyses for Head Injury Severity and Myocardial Injury

A growing body of literature indicates that beta-blocker administration after traumatic brain injury (TBI) is cerebroprotective, limiting secondary injury; however, the effects of preinjury beta blocker status remain poorly understood. We sought to characterize the effects of pre- and post-injury beta-blocker administration on mortality with subanalyses accounting for head injury severity and myocardial injury. In a Level II trauma center, all admissions of patients ≥18 years with a head Abbreviated Injury Scale Score ≥2, Glasgow Coma Scale ≤13 from May 2011 to May 2013 were queried. Demographic, injury-specific, and outcome variables were analyzed using univariate analyses. Subsequent multivariate analyses were conducted to determine adjusted odds of mortality for beta-blocker usage controlling for age, Injury Severity Score, head Abbreviated Injury Scale, arrival Glasgow Coma Scale, ventilator use, and intensive care unit stay. A total of 214 trauma admissions met inclusion criteria: 112 patients had neither pre- nor postinjury beta-blocker usage, 46 patients had preinjury beta-blocker usage, and 94 patients had postinjury beta-blocker usage. Both unadjusted and adjusted odds ratios of preinjury beta-blocker were insignificant with respect to mortality. However, postinjury in-hospital administration of beta blockers was found to significantly in the decrease of mortality in both univariate ( P = 0.002) and multivariate analyses ( P = 0.001). Our data indicate that beta-blocker administration post-TBI in hospital reduces odds of mortality; however, preinjury beta-blocker usage does not. Additionally, myocardial injury is a useful indicator for beta-blocker administration post-TBI. Further research into which beta blockers confer the best benefits as well as the optimal period of beta-blocker administration post-TBI is recommended.

Attenuation of cardiovascular stress with sympatholytics does not improve survival in patients with severe isolated traumatic brain injury

BACKGROUND

Studies have shown improved survival after traumatic brain injury (TBI) with the administration of sympatholytics, including β-blockers and clonidine, which is thought to attenuate the cardiovascular stress response. However, the use of sympatholytics has not been studied in patients with isolated severe TBI (ISTBI). We hypothesized that ISTBI patients receiving sympatholytics who demonstrated a reduction in cardiovascular stress would have improved outcomes compared with similarly injured patients without these cardiovascular changes.

METHODS

We reviewed the medical records of 338 ISTBI patients (head Abbreviated Injury Scale [AIS] score > 3 and associated injury AIS score < 1) admitted to a Level I trauma center from 2010 through 2014. All patients were managed according to Brain Trauma Foundation guidelines. Demographic, clinical, and survival probability data were gathered. The primary outcome was inpatient mortality. Cardiovascular stress was assessed using the rate-pressure product (RPP = systolic blood pressure × heart rate / 100) calculated both before and after sympatholytic administration. Associations between independent variables and mortality were adjusted for total hospital length of stay.

RESULTS

Among ISTBI patients, observed mortality was 6% (n = 20), while predicted mortality by Trauma and Injury Severity Score (TRISS) was 11% (n = 38). Administration of sympatholytics was associated with reduction in RPP in univariate analysis (p = 0.035). After adjusting for length of stay, neither receipt of β-blockers nor reduction in RPP was associated with survival. Mean reduction in RPP among survivors was not different from that among nonsurvivors (-4.0% vs. -11.9%, p = 0.148). In addition, RPP reduction among patients who received sympatholytics occurred at the same rate in survivors as nonsurvivors (67% vs. 68%, p = 0.894). Severity of head injury, intraventricular hemorrhage, and any intracranial operative intervention were significantly associated with mortality.

CONCLUSION

Although sympatholytic administration is associated with a significant decrease in RPP, the survival benefit seen in patients with multiple injuries with TBI is not observed among ISTBI patients. Further research on the role of sympatholysis in the management of ISTBI is warranted.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Propranolol and Mesenchymal Stromal Cells Combine to Treat Traumatic Brain Injury

More than 6.5 million patients are burdened by the physical, cognitive, and psychosocial deficits associated with traumatic brain injury (TBI) in the U.S. Despite extensive efforts to develop neuroprotective therapies for this devastating disorder, there have been no successful outcomes in human clinical trials to date. Retrospective studies have shown that β-adrenergic receptor blockers, specifically propranolol, significantly decrease mortality of TBI through mechanisms not yet fully elucidated but are thought to counterbalance a hyperadrenergic state resulting from a TBI. Conversely, cellular therapies have been shown to improve long-term behavior following TBI, likely by reducing inflammation. Given the nonredundancy in their therapeutic mechanisms, we hypothesized that a combination of acute propranolol followed by mesenchymal stem cells (MSCs) isolated from human bone marrow would have additive effects in treating a rodent model of TBI. We have found that the treatments are well-tolerated individually and in combination with no adverse events. MSCs decrease BBB permeability at 96 hours after injury, inhibit a significant accumulation of activated microglia/macrophage in the thalamic region of the brain both short and long term, and enhance neurogenesis short term. Propranolol decreases edema and reduces the number of fully activated microglia at 7 days and the number of semiactivated microglia at 120 days. Combinatory treatment improved cognitive and memory functions 120 days following TBI. Therefore, the results here suggest a new, efficacious sequential treatment for TBI may be achieved using the β-blocker propranolol followed by MSC treatment.

SIGNIFICANCE

Despite continuous efforts, traumatic brain injury (TBI) remains the leading cause of death and disability worldwide in patients under the age of 44. In this study, an animal model of moderate-severe TBI was treated with an acute dose of propranolol followed by a delayed dose of human mesenchymal stem cells (MSCs), resulting in improved short- and long-term measurements. These results have direct translational application. They reinforce the inevitable clinical trial of MSCs to treat TBI by demonstrating, among other benefits, a notable decrease in chronic neuroinflammation. More importantly, these results demonstrate that MSCs and propranolol, which is increasingly being used clinically for TBI, are compatible treatments that improve overall outcome.

Prospective evaluation of early propranolol after traumatic brain injury

BACKGROUND

Although beta-adrenergic receptor blockade may improve outcomes after traumatic brain injury (TBI), its early use is not routine. We hypothesize that judicious early low-dose propranolol after TBI (EPAT) will improve outcomes without altering bradycardia or hypotensive events.

METHODS

We conducted a prospective, observational study on all patients who presented with moderate-to-severe TBI from March 2010-August 2013. Ten initial patients did not receive propranolol (control). Subsequent patients received propranolol at 1-mg intravenous every 6 h starting within 12 h of intensive care unit (ICU) admission (EPAT) for a minimum of 48 h. Heart rate and blood pressure were recorded hourly for the first 72 h. Bradycardia and hypotensive events, mortality, and length of stay (LOS) were compared between cohorts to determine significant differences.

RESULTS

Thirty-eight patients were enrolled; 10 control and 28 EPAT. The two cohorts were similar when compared by gender, emergency department (ED) systolic blood pressure, ED heart rate, and mortality. ED Glasgow coma scale was lower (4.2 versus 10.7, P < 0.01) and injury severity score higher in control. EPAT patients received a mean of 10 ± 14 doses of propranolol. Hypotensive events were similar between cohorts, whereas bradycardia events were higher in control (5.8 versus 1.6, P = 0.05). ICU LOS (15.4 versus 30.4 d, P = 0.02) and hospital LOS (10 versus 19.1 d, P = 0.05) were lower in EPAT. Mortality rates were similar between groups (10% versus 10.7%, P = 0.9). The administration of propranolol led to no recorded complications.

CONCLUSIONS

Although bradycardia and hypotensive events occur early after TBI, low-dose intravenous propranolol does not increase their number or severity. Early use of propranolol after TBI appears to be safe and may be associated with decreased ICU and hospital LOS.

β-blockers in critically ill patients: from physiology to clinical evidence

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2015 and co-published as a series in Critical Care. Other articles in the series can be found online at http://ccforum.com/series/annualupdate2015. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Cardiovascular manifestations of neurologic disease

Cardiac manifestations of neurologic diseases are common in clinical practice. There are numerous anatomic and pathophysiologic links between the normal and abnormal function of both systems. There are a number of brain-heart interactions which affect the care of patients as well as help guide therapeutic development. This is exemplified in the area of vascular neurology where knowledge of the brain-heart connection is essential not only for bedside management but where collaborative efforts between neurology and cardiology are key in developing new strategies for ischemic stroke prevention and treatment, atrial fibrillation, and interventional techniques. This chapter will focus on cardiac manifestations of neurologic disease, with special emphasis on vascular and intensive care neurology, epilepsy, and neurodegenerative and peripheral nervous system diseases.

Decreasing adrenergic or sympathetic hyperactivity after severe traumatic brain injury using propranolol and clonidine (DASH After TBI Study): study protocol for a randomized controlled trial

Background

Severe TBI, defined as a Glasgow Coma Scale ≤ 8, increases intracranial pressure and activates the sympathetic nervous system. Sympathetic hyperactivity after TBI manifests as catecholamine excess, hypertension, abnormal heart rate variability, and agitation, and is associated with poor neuropsychological outcome. Propranolol and clonidine are centrally acting drugs that may decrease sympathetic outflow, brain edema, and agitation. However, there is no prospective randomized evidence available demonstrating the feasibility, outcome benefits, and safety for adrenergic blockade after TBI.

Methods/Design

The DASH after TBI study is an actively accruing, single-center, randomized, double-blinded, placebo-controlled, two-arm trial, where one group receives centrally acting sympatholytic drugs, propranolol (1 mg intravenously every 6 h for 7 days) and clonidine (0.1 mg per tube every 12 h for 7 days), and the other group, double placebo, within 48 h of severe TBI. The study uses a weighted adaptive minimization randomization with categories of age and Marshall head CT classification. Feasibility will be assessed by ability to provide a neuroradiology read for randomization, by treatment contamination, and by treatment compliance. The primary endpoint is reduction in plasma norepinephrine level as measured on day 8. Secondary endpoints include comprehensive plasma and urine catecholamine levels, heart rate variability, arrhythmia occurrence, infections, agitation measures using the Richmond Agitation-Sedation Scale and Agitated Behavior scale, medication use (anti-hypertensive, sedative, analgesic, and antipsychotic), coma-free days, ventilator-free days, length of stay, and mortality. Neuropsychological outcomes will be measured at hospital discharge and at 3 and 12 months. The domains tested will include global executive function, memory, processing speed, visual-spatial, and behavior. Other assessments include the Extended Glasgow Outcome Scale and Quality of Life after Brain Injury scale. Safety parameters evaluated will include cardiac complications.

Discussion

The DASH After TBI Study is the first randomized, double-blinded, placebo-controlled trial powered to determine feasibility and investigate safety and outcomes associated with adrenergic blockade in patients with severe TBI. If the study results in positive trends, this could provide pilot evidence for a larger multicenter randomized clinical trial. If there is no effect of therapy, this trial would still provide a robust prospective description of sympathetic hyperactivity after TBI.

Trial registration

ClinicalTrials.gov NCT01322048

Neuroprotective effects of selective β-1 adrenoceptor antagonists, landiolol and esmolol, on transient forebrain ischemia in rats; a dose-response study

Although selective beta-1 adrenoceptor antagonists are known to provide neuroprotective effects after brain ischemia, dose-response relationships of their neuroprotective effects have not been examined. The present study was conducted to evaluate whether the degree of brain protection against transient forebrain ischemia would be influenced by different doses of selective beta-1 adrenoceptor antagonists, esmolol and landiolol, in rats. Adult male S.D. rats received intravenous infusion of saline 0.5 ml/h, esmolol 20, 200, 2,000 μg/kg/min, or landiolol 5, 50, 500 μg/kg/min. Infusion was initiated 30 min prior to ischemia and continued for 24h. Ten-minute forebrain ischemia was induced by hemorrhagic hypotension and occlusion of the bilateral carotid arteries. Neurological and histological examinations were performed. Neurological deficit scores at 1, 4 and 7 days were lower, and the number of intact neurons in CA1 hippocampal region was larger in the rats treated with esmolol and landiolol after ischemia, compared with saline-treated rats (P<0.05), whereas no difference was found among different doses of esmolol and landiolol. These results suggested that selective beta-1 adrenoceptor antagonists improved neurological and histological outcomes following forebrain ischemia in rats, irrespective of their doses.

The impact of beta-blocker therapy on anemia after traumatic brain injury

BACKGROUND

An increase in endogenous catecholamine levels after traumatic brain injury (TBI) is well described. Animal studies suggest that postinjury anemia is exacerbated by a persistent hyperadrenergic state. This study aims to determine if beta-blocker (BB) exposure affects anemia after TBI.

STUDY DESIGN AND METHODS

We reviewed a Level I trauma registry for patients with TBI, examining markers of anemia between patients who received BB with those who did not.

RESULTS

A total of 174 patients were exposed to BB (BB+) and 245 were not exposed (BB-). The mean age in the BB+ group was 50 years (vs. 36 years in BB- group, p < 0.001). The mean injury severity score was 33.6 for the BB+ group (vs. 30.8 for BB- group, p = 0.01). While BB+ patients were more likely to receive a transfusion (60.9% vs. 35.1%, p < 0.001), BB+ patients reached their nadir hemoglobin (Hb) at a later day of hospitalization and their rate of decrease in Hb was significantly slower (both p < 0.001). Choosing Hb cutoffs for anemia of both 7 and 10 g/dL, Kaplan-Meier demonstrated a significant delay in time to anemia.

CONCLUSION

This study suggests beta-blockade delays anemia after TBI. Elaboration of this effect may demonstrate an additional benefit of beta-blockade after head injury.

Multimodal Analysis: New Approaches to the Concussion Conundrum

Sports-related concussions are complex injuries with biomechanical and biochemical etiology that present with central and autonomic nervous system dysfunction. Current methods for assessing concussions and basing return-to-play decisions rely on symptom resolution, rating scales, and neuropsychological testing, all of which are indirect measures of injury severity and detect functional capabilities but do not directly measure injury location or severity. In addition, these downstream measures are susceptible to false negatives because compensatory mechanism, such as unmasking and redundancies in brain circuitry can return functional capabilities before injury resolution. The multifactorial nature of concussion necessitates rapid, inexpensive, and easily applied multimodal analysis methods that can offer greater sensitivity and specificity. This article discusses how new approaches utilizing electrophysiology (e.g., QEEG, ERP, ECG, HRV), quantified balance measures, and biochemistry are necessary to advance the science of concussion assessment, treatment, recovery projections, and return-to-play decisions. These additional assessment tools offer a more direct window into the severity and location of the injury, real-time measures of brain function, and the ability to measure the multiple body systems negatively affected by concussion.

Mortality is reduced for heart rate 80 to 89 after traumatic brain injury

BACKGROUND

Increasing data indicate treatment with beta blockers might improve survival after traumatic brain injury (TBI); the optimal heart rate (HR) range for these patients is unknown. To guide treatment, admission HR in moderate to severe TBI patients was analyzed to determine if a specific range is associated with decreased mortality.

METHODS

The Los Angeles County Trauma System Database, consisting of five Level I and 8 Level II trauma centers, was queried for all injured patients admitted between 1998 and 2005 (n = 147,788). Isolated moderate to severe TBI patients (head abbreviated injury score > or = 3) were then identified. Demographics and outcomes were compared at various admission HR subgroups (<50, 50-59, 60-69, 70-79, 80-89, 90-99, 100-109, > or =110). Logistic regression was then performed to determine predictors of mortality.

RESULTS

After exclusions, a total of 11,977 isolated moderate to severe isolated TBI patients were analyzed, overall mortality was 11.5% with a trend toward lowest mortality at HR 80 to 89 (7.3%). Each HR subgroup had a significantly increased unadjusted odds ratio for mortality compared with HR 80 to 89, except HR 90 to 99 (OR 1.2, CI 1.0-1.5) and HR 100 to 109 (OR 1.2, CI 1.0-1.5). In multivariable logistic regression analysis, HR <50, 50-59, 60-69, and > or =110 were independent predictors for increased mortality compared with HR 80-89.

CONCLUSION

After isolated moderate to severe TBI, HR <50, 50-59, 60-69, and > or =110 were independent predictors of increased mortality. HR outside the range 70-109 could serve as a marker for aggressive resuscitation. As mortality increased significantly with HR: <50 (AOR 4.70), 50-59 (AOR 2.21), and 60-69 (AOR 1.63), our findings recommend avoiding HR < 70 in patients with moderate to severe TBI.

Preinjury statin use is associated with a higher risk of multiple organ failure after injury: a propensity score adjusted analysis

BACKGROUND

Recent studies suggest that statin use may improve outcome in critically ill patients. This has been attributed to the pleiomorphic effect and modulation of inflammatory mediators that occurs with statin use. We sought to determine whether preinjury statin (PIS) use was associated with improved outcome in severely injured blunt trauma patients.

METHODS

Data were obtained from a multicenter prospective cohort study evaluating outcomes in blunt injured adults with hemorrhagic shock. Patients aged 55 years and older were analyzed. Those with isolated traumatic brain injury, cervical cord injury, and those who survived <24 hours were excluded. A propensity score predicting statin use was created using logistic regression. Cox proportional hazard regression was then used to evaluate the effects of PIS use on mortality and the development of multiple organ failure (MOF, multiple organ dysfunction syndrome >5) and nosocomial infection (NI) after adjusting for important injury characteristics and the propensity of taking PISs.

RESULTS

Overall mortality and MOF rates for the study cohort (n = 295) were 21% and 50%, respectively. Over 24% of patients (n = 71) reported PIS use. Kaplan-Meier analysis revealed no difference in NI or mortality over time but did show a significant higher incidence of MOF in those with PIS use (p = 0.04). Regression analysis verified PIS was independently associated with an 80% higher risk of MOF (hazard ratio: 1.8; 95% confidence interval, 1.1-2.9) and was found to be one of the strongest independent risk factors for the development of MOF.

CONCLUSION

PIS use was independently associated with a higher risk of MOF postinjury. These results are contrary to previous analyses. The protective effect of statins may be lost in the severely injured, and modulation of the inflammatory response may result in higher morbidity. Further studies are required to better understand the impact and potential therapeutic utility of this commonly prescribed medication both before and after injury.

Sympathetic overstimulation during critical illness: adverse effects of adrenergic stress

The term ''adrenergic'' originates from ''adrenaline'' and describes hormones or drugs whose effects are similar to those of epinephrine. Adrenergic stress is mediated by stimulation of adrenergic receptors and activation of post-receptor pathways. Critical illness is a potent stimulus of the sympathetic nervous system. It is undisputable that the adrenergic-driven ''fight-flight response'' is a physiologically meaningful reaction allowing humans to survive during evolution. However, in critical illness an overshooting stimulation of the sympathetic nervous system may well exceed in time and scope its beneficial effects. Comparable to the overwhelming immune response during sepsis, adrenergic stress in critical illness may get out of control and cause adverse effects. Several organ systems may be affected. The heart seems to be most susceptible to sympathetic overstimulation. Detrimental effects include impaired diastolic function, tachycardia and tachyarrhythmia, myocardial ischemia, stunning, apoptosis and necrosis. Adverse catecholamine effects have been observed in other organs such as the lungs (pulmonary edema, elevated pulmonary arterial pressures), the coagulation (hypercoagulability, thrombus formation), gastrointestinal (hypoperfusion, inhibition of peristalsis), endocrinologic (decreased prolactin, thyroid and growth hormone secretion) and immune systems (immunomodulation, stimulation of bacterial growth), and metabolism (increase in cell energy expenditure, hyperglycemia, catabolism, lipolysis, hyperlactatemia, electrolyte changes), bone marrow (anemia), and skeletal muscles (apoptosis). Potential therapeutic options to reduce excessive adrenergic stress comprise temperature and heart rate control, adequate use of sedative/analgesic drugs, and aiming for reasonable cardiovascular targets, adequate fluid therapy, use of levosimendan, hydrocortisone or supplementary arginine vasopressin.

Cortical thickness abnormalities in cocaine addiction--a reflection of both drug use and a pre-existing disposition to drug abuse?

The structural effects of cocaine on neural systems mediating cognition and motivation are not well known. By comparing the thickness of neocortical and paralimbic brain regions between cocaine-dependent and matched control subjects, we found that four of 18 a priori regions involved with executive regulation of reward and attention were significantly thinner in addicts. Correlations were significant between thinner prefrontal cortex and reduced keypresses during judgment and decision making of relative preference in addicts, suggesting one basis for restricted behavioral repertoires in drug dependence. Reduced effortful attention performance in addicts also correlated with thinner paralimbic cortices. Some thickness differences in addicts were correlated with cocaine use independent of nicotine and alcohol, but addicts also showed diminished thickness heterogeneity and altered hemispheric thickness asymmetry. These observations suggest that brain structure abnormalities in addicts are related in part to drug use and in part to predisposition toward addiction.

Beta blockers exposure and traumatic brain injury: a literature review

Traumatic brain injury (TBI) continues to carry a significant public health burden and is anticipated to worsen worldwide over the next century. Recently the authors of several articles have suggested that exposure to beta blockers may improve mortality rates following TBI. The exact mechanism through which beta blockers mediate this effect is unknown. In this paper, the authors review the literature regarding the safety of beta blockers in patients with TBI. The findings of several recent retrospective cohort studies are examined and implications for future investigation are discussed. Future questions to be addressed include: the specific indications for the use of beta blockers in patients with TBI, the optimal type and dose of beta blocker given, the end point of beta blocker therapy, and the safety of beta blockers in cases of severe TBIs.