Glasgow Outcome Scale Measures and Impact on Analysis and Results of a Randomized Clinical Trial of Severe Traumatic Brain Injury

The original unstructured Glasgow Outcome Scale (uGOS) and the newer structured interviews GOS and the Extended GOS (GOS-E) have been used widely as outcomes in severe traumatic brain injury (TBI) trials. We compared outcome categories (ranging from dead [D] to good recovery [GR]) for each measure in a randomized trial of transfusion threshold and the implications of measure choice and analysis methods for the results of the trial. We planned to explore patient symptomology possibly driving any discrepancies between the patient's uGOS and GOS scores. Category correspondence between uGOS and GOS scores occurred in 160 (88.4%) of the 181 analyzed cases. The GOS-E and GOS instruments incorporated more behavioral/cognitive/social and other components, leading to a worse outcome in some cases than for the uGOS. Choice of outcome measure and analysis led to incongruous conclusions. Dichotomizing uGOS into favorable outcome (GR and moderate disability [MD] categories) versus unfavorable (severe disability [SD], vegetative state [VS], and D categories), we observed a significant effect of transfusion threshold (odds ratio [OR] = 0.51, p = 0.03; adjusted OR = 0.40, p = 0.02). For the same dichotomization of GOS and GOS-E, the effect was not statistically significant but the ORs were similar (ORs between 0.57 and 0.68, p > 0.15 for all). An effect was not detected using ordinal logistic regression or sliding dichotomy method for all three measures. Differences in categorizations of subjects between moderate and severe disability among the scales impacted conclusions of the trial. In future studies, particular attention should be given to implementing GOS measures and describing the methodology for how outcomes were ascertained.

Prognosis of Six-Month Glasgow Outcome Scale in Severe Traumatic Brain Injury Using Hospital Admission Characteristics, Injury Severity Characteristics, and Physiological Monitoring during the First Day Post-Injury

Gold standard prognostic models for long-term outcome in patients with severe traumatic brain injury (TBI) use admission characteristics and are considered useful in some areas but not for clinical practice. In this study, we aimed to build prognostic models for 6-month Glasgow Outcome Score (GOS) in patients with severe TBI, combining baseline characteristics with physiological, treatment, and injury severity data collected during the first 24 h after injury. We used a training dataset of 472 TBI subjects and several data mining algorithms to predict the long-term neurological outcome. Performance of these algorithms was assessed in an independent (test) sample of 158 subjects. The least absolute shrinkage and selection operator (LASSO) led to the highest prediction accuracy (area under the receiving operating characteristic curve = 0.86) in the test set. The most important post-baseline predictor of GOS was the best motor Glasgow Coma Scale (GCS) recorded in the first day post-injury. The LASSO model containing the best motor GCS and baseline variables as predictors outperformed a model with baseline data only. TBI patient physiology of the first day-post-injury did not have a major contribution to patient prognosis six months after injury. In conclusion, 6-month GOS in patients with TBI can be predicted with good accuracy by the end of the first day post-injury, using hospital admission data and information on the best motor GCS achieved during those first 24 h post-injury. Passed the first day after injury, important physiological predictors could emerge from landmark analyses, leading to prediction models of higher accuracy than the one proposed in the current research.

Functional and Structural Improvement with a Catalytic Carbon Nano-Antioxidant in Experimental Traumatic Brain Injury Complicated by Hypotension and Resuscitation

Hypotension worsens outcome after all severities of traumatic brain injury (TBI), with loss of cerebral autoregulation being a potential contributor. Previously, we demonstrated that intravenous injection of a high capacity catalytic antioxidant, poly(ethylene)glycol conjugated hydrophilic carbon clusters (PEG-HCCs) rapidly restored cerebral perfusion and acutely restored brain oxidative balance in a TBI model complicated by hemorrhagic hypotension without evidence of toxicity. Here, we tested whether these acute effects translated into behavioral and structural benefit. TBI was generated by a cortical contusion impactor in 38 Long Evans rats, followed by blood withdrawal to a target mean arterial pressure of 40 mm Hg. PEG-HCC (2 mg/kg) or diluent was injected intravenously 80 min later at the onset of blood resuscitation followed by another injection 2 h later (doses determined in prior studies). Performance on beam walking (performed on days 1-5) and Morris water maze (MWM) (performed on days 11-15) was tested, and lesion size was determined at the termination. PEG-HCC treatment nearly completely prevented motor dysfunction (p < 0.001 vs. diluent), improved MWM performance (p < 0.001; treatment vs. time interaction) and reduced lesion size by 61% (p = 0.054). Here we show that treatment with PEG-HCCs at a clinically realistic time point (onset of resuscitation) prevented a major portion of the neurological dysfunction induced in this TBI model, and that PEG-HCCs are candidates for additional study as a potential therapeutic agent.

Risk of Posttraumatic Stress Disorder and Major Depression in Civilian Patients After Mild Traumatic Brain Injury: A TRACK-TBI Study

IMPORTANCE

Traumatic brain injury (TBI) has been associated with adverse mental health outcomes, such as posttraumatic stress disorder (PTSD) and major depressive disorder (MDD), but little is known about factors that modify risk for these psychiatric sequelae, particularly in the civilian sector.

OBJECTIVE

To ascertain prevalence of and risk factors for PTSD and MDD among patients evaluated in the emergency department for mild TBI (mTBI).

DESIGN, SETTING, AND PARTICIPANTS

Prospective longitudinal cohort study (February 2014 to May 2018). Posttraumatic stress disorder and MDD symptoms were assessed using the PTSD Checklist for DSM-5 and the Patient Health Questionnaire-9 Item. Risk factors evaluated included preinjury and injury characteristics. Propensity score weights-adjusted multivariable logistic regression models were performed to assess associations with PTSD and MDD. A total of 1155 patients with mTBI (Glasgow Coma Scale score, 13-15) and 230 patients with nonhead orthopedic trauma injuries 17 years and older seen in 11 US hospitals with level 1 trauma centers were included in this study.

MAIN OUTCOMES AND MEASURES

Probable PTSD (PTSD Checklist for DSM-5 score, ≥33) and MDD (Patient Health Questionnaire-9 Item score, ≥15) at 3, 6, and 12 months postinjury.

RESULTS

Participants were 1155 patients (752 men [65.1%]; mean [SD] age, 40.5 [17.2] years) with mTBI and 230 patients (155 men [67.4%]; mean [SD] age, 40.4 [15.6] years) with nonhead orthopedic trauma injuries. Weights-adjusted prevalence of PTSD and/or MDD in the mTBI vs orthopedic trauma comparison groups at 3 months was 20.0% (SE, 1.4%) vs 8.7% (SE, 2.2%) (P < .001) and at 6 months was 21.2% (SE, 1.5%) vs 12.1% (SE, 3.2%) (P = .03). Risk factors for probable PTSD at 6 months after mTBI included less education (adjusted odds ratio, 0.89; 95% CI, 0.82-0.97 per year), being black (adjusted odds ratio, 5.11; 95% CI, 2.89-9.05), self-reported psychiatric history (adjusted odds ratio, 3.57; 95% CI, 2.09-6.09), and injury resulting from assault or other violence (adjusted odds ratio, 3.43; 95% CI, 1.56-7.54). Risk factors for probable MDD after mTBI were similar with the exception that cause of injury was not associated with increased risk.

CONCLUSIONS AND RELEVANCE

After mTBI, some individuals, on the basis of education, race/ethnicity, history of mental health problems, and cause of injury were at substantially increased risk of PTSD and/or MDD. These findings should influence recognition of at-risk individuals and inform efforts at surveillance, follow-up, and intervention.

IMPACT probability of poor outcome and plasma cytokine concentrations are associated with multiple organ dysfunction syndrome following traumatic brain injury

OBJECTIVE

Traumatic brain injury (TBI) is a major cause of morbidity and mortality. Multiple organ dysfunction syndrome (MODS) occurs frequently after TBI and independently worsens outcome. The present study aimed to identify potential admission characteristics associated with post-TBI MODS.

METHODS

The authors performed a secondary analysis of a recent randomized clinical trial studying the effects of erythropoietin and blood transfusion threshold on neurological recovery after TBI. Admission clinical, demographic, laboratory, and imaging parameters were used in a multivariable Cox regression analysis to identify independent risk factors for MODS following TBI, defined as maximum total Sequential Organ Failure Assessment (SOFA) score > 7 within 10 days of TBI.

RESULTS

Two hundred patients were initially recruited and 166 were included in the final analysis. Respiratory dysfunction was the most common nonneurological organ system dysfunction, occurring in 62% of the patients. International Mission for Prognosis and Analysis of Clinical Trials (IMPACT) probability of poor outcome at admission was significantly associated with MODS following TBI (odds ratio [OR] 8.88, 95% confidence interval [CI] 1.94-42.68, p < 0.05). However, more commonly used measures of TBI severity, such as the Glasgow Coma Scale, Injury Severity Scale, and Marshall classification, were not associated with post-TBI MODS. In addition, initial plasma concentrations of interleukin (IL)-6, IL-8, and IL-10 were significantly associated with the development of MODS (OR 1.47, 95% CI 1.20-1.80, p < 0.001 for IL-6; OR 1.26, 95% CI 1.01-1.58, p = 0.042 for IL-8; OR 1.77, 95% CI 1.24-2.53, p = 0.002 for IL-10) as well as individual organ dysfunction (SOFA component score ≥ 1). Finally, MODS following TBI was significantly associated with mortality (OR 5.95, 95% CI 2.18-19.14, p = 0.001), and SOFA score was significantly associated with poor outcome at 6 months (Glasgow Outcome Scale score < 4) when analyzed as a continuous variable (OR 1.21, 95% CI 1.06-1.40, p = 0.006).

CONCLUSIONS

Admission IMPACT probability of poor outcome and initial plasma concentrations of IL-6, IL-8, and IL-10 were associated with MODS following TBI.

Pre-Clinical Testing of Therapies for Traumatic Brain Injury

Despite the large number of promising neuroprotective agents identified in experimental traumatic brain injury (TBI) studies, none has yet shown meaningful improvements in long-term outcome in clinical trials. To develop recommendations and guidelines for pre-clinical testing of pharmacological or biological therapies for TBI, the Moody Project for Translational Traumatic Brain Injury Research hosted a symposium attended by investigators with extensive experience in pre-clinical TBI testing. The symposium participants discussed issues related to pre-clinical TBI testing including experimental models, therapy and outcome selection, study design, data analysis, and dissemination. Consensus recommendations included the creation of a manual of standard operating procedures with sufficiently detailed descriptions of modeling and outcome measurement procedures to permit replication. The importance of the selection of clinically relevant outcome variables, especially related to behavior testing, was noted. Considering the heterogeneous nature of human TBI, evidence of therapeutic efficacy in multiple, diverse (e.g., diffuse vs. focused) rodent models and a species with a gyrencephalic brain prior to clinical testing was encouraged. Basing drug doses, times, and routes of administration on pharmacokinetic and pharmacodynamic data in the test species was recommended. Symposium participants agreed that the publication of negative results would reduce costly and unnecessary duplication of unsuccessful experiments. Although some of the recommendations are more relevant to multi-center, multi-investigator collaborations, most are applicable to pre-clinical therapy testing in general. The goal of these consensus guidelines is to increase the likelihood that therapies that improve outcomes in pre-clinical studies will also improve outcomes in TBI patients.

Secondary brain injury: Predicting and preventing insults

Mortality or severe disability affects the majority of patients after severe traumatic brain injury (TBI). Adherence to the brain trauma foundation guidelines has overall improved outcomes; however, traditional as well as novel interventions towards intracranial hypertension and secondary brain injury have come under scrutiny after series of negative randomized controlled trials. In fact, it would not be unfair to say there has been no single major breakthrough in the management of severe TBI in the last two decades. One plausible hypothesis for the aforementioned failures is that by the time treatment is initiated for neuroprotection, or physiologic optimization, irreversible brain injury has already set in. We, and others, have recently developed predictive models based on machine learning from continuous time series of intracranial pressure and partial brain tissue oxygenation. These models provide accurate predictions of physiologic crises events in a timely fashion, offering the opportunity for an earlier application of targeted interventions. In this article, we review the rationale for prediction, discuss available predictive models with examples, and offer suggestions for their future prospective testing in conjunction with preventive clinical algorithms. This article is part of the Special Issue entitled "Novel Treatments for Traumatic Brain Injury".

Temporal Profile of Microtubule-Associated Protein 2: A Novel Indicator of Diffuse Brain Injury Severity and Early Mortality after Brain Trauma

This study compared cerebrospinal fluid (CSF) levels of microtubule-associated protein 2 (MAP-2) from adult patients with severe traumatic brain injury (TBI) with uninjured controls over 10 days, and examined the relationship between MAP-2 concentrations and acute clinical and radiologic measures of injury severity along with mortality at 2 weeks and over 6 months. This prospective study, conducted at two Level 1 trauma centers, enrolled adults with severe TBI (Glasgow Coma Scale [GCS] score ≤8) requiring a ventriculostomy, as well as controls. Ventricular CSF was sampled from each patient at 6, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216, and 240 h following TBI and analyzed via enzyme-linked immunosorbent assay for MAP-2 (ng/mL). Injury severity was assessed by the GCS score, Marshall Classification on computed tomography (CT), Rotterdam CT score, and mortality. There were 151 patients enrolled-130 TBI and 21 control patients. MAP-2 was detectable within 6 h of injury and was significantly elevated compared with controls (p < 0.001) at each time-point. MAP-2 was highest within 72 h of injury and decreased gradually over 10 days. The area under the receiver operating characteristic curve for deciphering TBI versus controls at the earliest time-point CSF was obtained was 0.96 (95% CI 0.93-0.99) and for the maximal 24-h level was 0.98 (95% CI 0.97-1.00). The area under the curve for initial MAP-2 levels predicting 2-week mortality was 0.80 at 6 h, 0.81 at 12 h, 0.75 at 18 h, 0.75 at 24 h, and 0.80 at 48 h. Those with Diffuse Injury III-IV had much higher initial (p = 0.033) and maximal (p = 0.003) MAP-2 levels than those with Diffuse Injury I-II. There was a graded increase in the overall levels and peaks of MAP-2 as the degree of diffuse injury increased within the first 120 h post-injury. These data suggest that early levels of MAP-2 reflect severity of diffuse brain injury and predict 2-week mortality in TBI patients. These findings have implications for counseling families and improving clinical decision making early after injury and guiding multidisciplinary care. Further studies are needed to validate these findings in a larger sample.

Morbidity and mortality associated with hypernatremia in patients with severe traumatic brain injury

OBJECTIVE

Hypernatremia is independently associated with increased mortality in critically ill patients. Few studies have evaluated the impact of hypernatremia on early mortality in patients with severe traumatic brain injury (TBI) treated in a neurocritical care unit.

METHODS

A retrospective review of patients with severe TBI (admission Glasgow Coma Scale score ≤ 8) treated in a single neurocritical care unit between 1986 and 2012 was performed. Patients with at least 3 serum sodium values were selected for the study. Patients with diabetes insipidus and those with hypernatremia on admission were excluded. The highest serum sodium level during the hospital stay was recorded, and hypernatremia was classified as none (≤ 150 mEq/L), mild (151–155 mEq/L), moderate (156–160 mEq/L), and severe (> 160 mEq/L). Multivariate Cox regression analysis was performed to determine independent predictors of early mortality.

RESULTS

A total of 588 patients with severe TBI were studied. The median number of serum sodium measurements for patients in this study was 17 (range 3–190). No hypernatremia was seen in 371 patients (63.1%), mild hypernatremia in 77 patients (13.1%), moderate hypernatremia in 50 patients (8.5%), and severe hypernatremia in 90 patients (15.3%). Hypernatremia was detected within the 1st week of admission in 79.3% of patients (n = 172), with the majority of patients (46%) being diagnosed within 72 hours after admission. Acute kidney injury, defined as a rise in creatinine of ≥ 0.3 mg/dl, was observed in 162 patients (27.6%) and was significantly associated with the degree of hypernatremia (p < 0.001). At discharge, 148 patients (25.2%) had died. Hypernatremia was a significant independent predictor of mortality (hazard ratios for mild: 3.4, moderate: 4.4, and severe: 8.4; p < 0.001). Survival analysis showed significantly lower survival rates for patients with greater degrees of hypernatremia (log-rank test, p < 0.001).

CONCLUSIONS

Hypernatremia after admission in patients with severe TBI was independently associated with greater risk of early mortality. In addition to severe hypernatremia, mild and moderate hypernatremia were significantly associated with increased early mortality in patients with severe TBI.

Quantitative cerebral blood flow using xenon-enhanced CT after decompressive craniectomy in traumatic brain injury

OBJECTIVE Few studies have reported on changes in quantitative cerebral blood flow (CBF) after decompressive craniectomy and the impact of these measures on clinical outcome. The aim of the present study was to evaluate global and regional CBF patterns in relation to cerebral hemodynamic parameters in patients after decompressive craniectomy for traumatic brain injury (TBI). METHODS The authors studied clinical and imaging data of patients who underwent xenon-enhanced CT (XeCT) CBF studies after decompressive craniectomy for evacuation of a mass lesion and/or to relieve intractable intracranial hypertension. Cerebral hemodynamic parameters prior to decompressive craniectomy and at the time of the XeCT CBF study were recorded. Global and regional CBF after decompressive craniectomy was measured using XeCT. Regional cortical CBF was measured under the craniectomy defect as well as for each cerebral hemisphere. Associations between CBF, cerebral hemodynamics, and early clinical outcome were assessed. RESULTS Twenty-seven patients were included in this study. The majority of patients (88.9%) had an initial Glasgow Coma Scale score ≤ 8. The median time between injury and decompressive surgery was 9 hours. Primary decompressive surgery (within 24 hours) was performed in the majority of patients (n = 18, 66.7%). Six patients had died by the time of discharge. XeCT CBF studies were performed a median of 51 hours after decompressive surgery. The mean global CBF after decompressive craniectomy was 49.9 ± 21.3 ml/100 g/min. The mean cortical CBF under the craniectomy defect was 46.0 ± 21.7 ml/100 g/min. Patients who were dead at discharge had significantly lower postcraniectomy CBF under the craniectomy defect (30.1 ± 22.9 vs 50.6 ± 19.6 ml/100 g/min; p = 0.039). These patients also had lower global CBF (36.7 ± 23.4 vs 53.7 ± 19.7 ml/100 g/min; p = 0.09), as well as lower CBF for the ipsilateral (33.3 ± 27.2 vs 51.8 ± 19.7 ml/100 g/min; p = 0.07) and contralateral (36.7 ± 19.2 vs 55.2 ± 21.9 ml/100 g/min; p = 0.08) hemispheres, but these differences were not statistically significant. The patients who died also had significantly lower cerebral perfusion pressure (52 ± 17.4 vs 75.3 ± 10.9 mm Hg; p = 0.001). CONCLUSIONS In the presence of global hypoperfusion, regional cerebral hypoperfusion under the craniectomy defect is associated with early mortality in patients with TBI. Further study is needed to determine the value of incorporating CBF studies into clinical decision making for severe traumatic brain injury.

Clinical characteristics and temporal profile of recovery in patients with favorable outcomes at 6 months after severe traumatic brain injury

OBJECTIVE Early withdrawal of life-sustaining treatment due to expected poor prognosis is responsible for the majority of in-house deaths in severe traumatic brain injury (TBI). With increased focus on the decision and timing of withdrawal of care in patients with severe TBI, data on early neurological recovery in patients with a favorable outcome is needed to guide physicians and families. METHODS The authors reviewed prospectively collected data obtained in 1241 patients with head injury who were treated between 1986 and 2012. Patients with severe TBI, motor Glasgow Coma Scale (mGCS) score < 6 on admission, and those who had favorable outcomes (Glasgow Outcome Scale [GOS] score of 4 or 5, indicating moderate disability or good recovery) at 6 months were selected. Baseline demographic, clinical, and imaging data were analyzed. The time from injury to the first record of following commands (mGCS score of 6) after injury was recorded. The temporal profile of GOS scores from discharge to 6 months after the injury was also assessed. RESULTS The authors studied 218 patients (183 male and 35 female) with a mean age of 28.9 ± 11.2 years. The majority of patients were able to follow commands (mGCS score of 6) within the 1st week after injury (71.4%), with the highest percentage of patients in this group recovering on Day 1 (28.6%). Recovery to the point of following commands beyond 2 weeks after the injury was seen in 14.8% of patients, who experienced significantly longer durations of intracranial pressure monitoring (p = 0.001) and neuromuscular blockade (p < 0.001). In comparison with patients with moderate disability, patients with good recovery had a higher initial GCS score (p = 0.01), lower incidence of anisocoria at admission (p = 0.048), and a shorter ICU stay (p < 0.001) and total hospital stay (p < 0.001). There was considerable improvement in GOS scores from discharge to follow-up at 6 months. CONCLUSIONS Up to 15% of patients with a favorable outcome after severe TBI may begin to follow commands beyond 2 weeks after the injury. These data caution against early withdrawal of life-sustaining treatment in patients with severe TBI.

Factors associated with shunt-dependent hydrocephalus after decompressive craniectomy for traumatic brain injury

OBJECTIVE Posttraumatic hydrocephalus (PTH) affects 11.9%-36% of patients undergoing decompressive craniectomy (DC) and is an important cause of morbidity after traumatic brain injury (TBI). Early diagnosis and treatment of PTH can prevent further neurological compromise in patients who are recovering from TBI. There is limited data on predictors of shunting for PTH after DC for TBI. METHODS Prospectively collected data from the erythropoietin severe TBI randomized controlled trial were studied. Demographic, clinical, and imaging data were analyzed for enrolled patients who underwent a DC. All head CT scans during admission were reviewed and assessed for PTH by the Gudeman criteria or the modified Frontal Horn Index ≥ 33%. The presence of subdural hygromas was categorized as unilateral/bilateral hemispheric or interhemispheric. Using L1-regularized logistic regression to select variables, a multiple logistic regression model was created with ventriculoperitoneal shunting as the binary outcome. Statistical significance was set at p < 0.05. RESULTS A total of 60 patients who underwent DC were studied. Fifteen patients (25%) underwent placement of a ventriculoperitoneal shunt for PTH. The majority of patients underwent unilateral decompressive hemicraniectomy (n = 46, 77%). Seven patients (12%) underwent bifrontal DC. Unilateral and bilateral hemispheric hygromas were noted in 31 (52%) and 7 (11%) patients, respectively. Interhemispheric hygromas were observed in 19 patients (32%). The mean duration from injury to first CT scan showing hemispheric subdural hygroma and interhemispheric hygroma was 7.9 ± 6.5 days and 14.9 ± 11.7 days, respectively. The median duration from injury to shunt placement was 43.7 days. Multivariate analysis showed that the presence of interhemispheric hygroma (OR 63.6, p = 0.001) and younger age (OR 0.78, p = 0.009) were significantly associated with the need for a shunt after DC. CONCLUSIONS The presence of interhemispheric subdural hygromas and younger age were associated with shunt-dependent hydrocephalus after DC in patients with severe TBI.

The Role of Multimodal Invasive Monitoring in Acute Traumatic Brain Injury

This article reviews the role of modalities that directly monitor brain parenchyma in patients with severe traumatic brain injury. The physiology monitored involves compartmental and perfusion pressures, tissue oxygenation and metabolism, quantitative blood flow, pressure autoregulation, and electrophysiology. There are several proposed roles for this multimodality monitoring, such as to track, prevent, and treat the cascade of secondary brain injury; monitor the neurologically injured patient; integrate various data into a composite, patient-specific, and dynamic picture; apply protocolized, pathophysiology-driven intensive care; use as a prognostic marker; and understand pathophysiologic mechanisms involved in secondary brain injury to develop preventive and abortive therapies, and to inform future clinical trials.

Phase II Clinical Trial of Atorvastatin in Mild Traumatic Brain Injury

Statins constitute a class of medications commonly used in the treatment of elevated cholesterol. However, in experimental studies, statins also have other non-cholesterol-mediated mechanisms of action, which may have neuroprotective effects. The aim of this study was to determine whether administration of atorvastatin for 7 days post-injury would improve neurological recovery in patients with mild traumatic brain injury (mTBI). The hypothesis was that atorvastatin administration would reduce post-concussion symptoms and also that atorvastatin administration for 1 week post-injury would be safe. One hundred forty patients with mTBI were planned to be enrolled and randomly assigned to receive atorvastatin 1 mg/kg (up to 80 mg/kg) per day or placebo for 7 days starting within 24 h of injury. Assessments of post-concussion syndrome, post-traumatic stress and depressive symptoms, cognition, memory, verbal fluency, functional, and work status were performed at baseline, 1 week, and 1 and 3 months. The result on the Rivermead Post-Concussion Symptoms Questionnaire at 3 months was the primary outcome. Enrollment in the trial was stopped early because of difficulty in recruiting sufficient numbers of subjects. Fifty-two patients with mTBI were enrolled; 28 patients received atorvastatin and 24 received placebo. The median Rivermead score was 2 for the atorvastatin group, compared to 3.5 for the placebo group, at 3 months post-injury (χ2(1) = 0.0976; p = 0.7547). The change in the Rivermead score between baseline and 3 months was also analyzed. The median decrease in score was 4 for the atorvastatin group and 10.5 for the placebo group (χ2(1) = 0.8750; p = 0.3496). No serious adverse events occurred, and there was no significant difference in the incidence of adverse events in the two treatment groups. Atorvastatin administration for 7 days post-injury was safe, but there were no significant differences in neurological recovery post-mTBI with atorvastatin.

Plasma cytokines IL-6, IL-8, and IL-10 are associated with the development of acute respiratory distress syndrome in patients with severe traumatic brain injury

Background

Patients with severe traumatic brain injury (TBI) are at risk of the development of acute respiratory distress syndrome (ARDS). TBI and ARDS pathophysiologic mechanisms are known to independently involve significant inflammatory responses. The literature on the association between plasma inflammatory cytokines and ARDS in patients with TBI is sparse.

Methods

The study was a secondary analysis of the safety of a randomized trial of erythropoietin and transfusion threshold in patients with severe TBI. Inflammatory markers within the first 24 hours after injury were compared in patients who developed ARDS and patients without ARDS, using Cox proportional hazards models.

Results

There were 200 patients enrolled in the study. The majority of plasma and cerebrospinal fluid (CSF) cytokine levels were obtained within 6 hours. Plasma proinflammatory markers IL-6 and IL-8 and anti-inflammatory marker IL-10 were associated with the development of ARDS (adjusted hazard ratio (HR) = 1.55, confidence interval (CI) = 1.14, 2.11, P = 0.005 for IL-6; adjusted HR = 1.32, CI = 1.10, 1.59, P = 0.003 for IL-8).

Conclusion

Plasma markers of IL-6, IL-8, and IL-10 are associated with ARDS in patients with severe TBI.

Trial registration

NCT00313716 registered 4/2006

Clinical application of near-infrared spectroscopy in patients with traumatic brain injury: a review of the progress of the field

Near-infrared spectroscopy (NIRS) is a technique by which the interaction between light in the near-infrared spectrum and matter can be quantitatively measured to provide information about the particular chromophore. Study into the clinical application of NIRS for traumatic brain injury (TBI) began in the 1990s with early reports of the ability to detect intracranial hematomas using NIRS. We highlight the advances in clinical applications of NIRS over the past two decades as they relate to TBI. We discuss recent studies evaluating NIRS techniques for intracranial hematoma detection, followed by the clinical application of NIRS in intracranial pressure and brain oxygenation measurement, and conclude with a summary of potential future uses of NIRS in TBI patient management.

Finding family for prospective consent in emergency research

Background Innovative approaches are needed to allow for research in the emergency setting while not compromising either the rights or the interests of the subjects enrolled in such research. The emergency consent exception was developed to meet this need.

Purpose The goal was to describe the timing of initial contact with relatives and the timing of obtaining informed consent for a research study in patients with severe traumatic brain injury.

Methods The study was designed as a prospective, observational study of 129 patients enrolled in an emergency study of traumatic brain injury conducted under the emergency consent exception. Detailed descriptive information was collected both about the availability of relatives of patients enrolled in a study of traumatic brain injury to give prospective consent within the time period required for entering the study and about the extent to which they did give prospective consent during that time period.

Results The number of patients with relatives who could be contacted by research staff increased with time after injury, with 3% (95% CI=0 to 6%), 25% (95% CI=18 to 32%), and 43% (95% CI=35 to 52%) having family at 1, 3, and 6 h, respectively postinjury. An additional 15% were available within the next 6 h. The median time after injury to the initial family contact by the research staff was 2.0 h for patients who had relatives already present at the hospital and 5.7 h for patients whose family had already been contacted by the hospital. The percentage of family members actually giving prospective research consent was much smaller; only 18% actually gave prospective consent within 6 h postinjury. The proportion of critically ill patients with family available to give prospective consent for enrollment in emergency research studies depends primarily on the time period allowed for enrollment in the individual study and the length of the transition from initial contact to completed prospective consent.

Limitations The study was performed in a specific patient population and may not be generalizable to other settings.

Conclusions Careful attention should be paid by investigators and IRBs as to whether the emergency consent exception is really required for a particular study, or whether the study could proceed using only prospective consent with a longer recruitment period, more research sites, and a higher yield of available family members giving prospective consent. Measures that could shorten the time between initial contact and obtaining informed consent (for example, allowing consent over the phone rather than requiring written consent) might decrease the need for the emergency consent exception. Clinical Trials 2007; 4: 631—637. http://ctj.sagepub.com

Cortical Thickness in Mild Traumatic Brain Injury

Magnetic resonance imaging data were acquired at ∼24 h and ∼3 months post-injury on mild traumatic brain injury (mTBI; n = 75) and orthopedic injury (n = 60) cohorts. The mTBI subjects were randomly assigned to a treatment group with atorvastatin or a non-treatment mTBI group. The treatment group was further divided into drug and placebo subgroups. FreeSurfer software package was used to compute cortical thickness based on the three dimensional T1-weighted images at both time-points. Cross-sectional analysis was carried out to compare cortical thickness between the mTBI and control groups. Longitudinal unbiased templates were generated for all subjects and cortical thickness measurements were compared between baseline and follow-up scans in the mTBI group. At baseline, significant reduction in cortical thickness was observed in the left middle temporal and the right superior parietal regions in the mTBI group, relative to the control group (p = 0.01). At follow-up, significant cortical thinning was again observed in the left middle temporal cortex in the mTBI group. Further analysis revealed significant cortical thinning only in the non-treatment group relative to the control group. In the follow-up, small regions with significant but subtle cortical thinning and thickening were seen in the frontal, temporal, and parietal lobes in the left hemisphere in the non-treatment group only. Our results indicate that cortical thickness could serve as a useful measure in identifying subtle changes in mTBI patients.

Progressive hemorrhagic injury after severe traumatic brain injury: effect of hemoglobin transfusion thresholds

OBJECT There is limited literature available to guide transfusion practices for patients with severe traumatic brain injury (TBI). Recent studies have shown that maintaining a higher hemoglobin threshold after severe TBI offers no clinical benefit. The present study aimed to determine if a higher transfusion threshold was independently associated with an increased risk of progressive hemorrhagic injury (PHI), thereby contributing to higher rates of morbidity and mortality. METHODS The authors performed a secondary analysis of data obtained from a recently performed randomized clinical trial studying the effects of erythropoietin and blood transfusions on neurological recovery after severe TBI. Assigned hemoglobin thresholds (10 g/dl vs 7 g/dl) were maintained with packed red blood cell transfusions during the acute phase after injury. PHI was defined as the presence of new or enlarging intracranial hematomas on CT as long as 10 days after injury. A severe PHI was defined as an event that required an escalation of medical management or surgical intervention. Clinical and imaging parameters and transfusion thresholds were used in a multivariate Cox regression analysis to identify independent risk factors for PHI. RESULTS Among 200 patients enrolled in the trial, PHI was detected in 61 patients (30.5%). The majority of patients with PHI had a new, delayed contusion (n = 29) or an increase in contusion size (n = 15). The mean time interval between injury and identification of PHI was 17.2 ± 15.8 hours. The adjusted risk of severe PHI was 2.3 times higher for patients with a transfusion threshold of 10 g/dl (95% confidence interval 1.1-4.7; p = 0.02). Diffuse brain injury was associated with a lower risk of PHI events, whereas higher initial intracranial pressure increased the risk of PHI (p < 0.001). PHI was associated with a longer median length of stay in the intensive care unit (18.3 vs 14.4 days, respectively; p = 0.04) and poorer Glasgow Outcome Scale scores (42.9% vs 25.5%, respectively; p = 0.02) at 6 months. CONCLUSIONS A higher transfusion threshold of 10 g/dl after severe TBI increased the risk of severe PHI events. These results indicate the potential adverse effect of using a higher hemoglobin transfusion threshold after severe TBI.

The incidence of ARDS and associated mortality in severe TBI using the Berlin definition

BACKGROUND

The incidence of adult respiratory distress syndrome (ARDS) in severe traumatic brain injury (TBI) is poorly reported. Recently, a new definition for ARDS was proposed, the Berlin definition. The percentage of patients represented by TBI in the Berlin criteria study is limited. This study describes the incidence and associated mortality of ARDS in TBI patients.

METHODS

The study was an analysis of the safety of erythropoietin administration and transfusion threshold on the incidence of ARDS in severe TBI patients. Three reviewers independently assessed all patients enrolled in the study for acute lung injury/ARDS using the Berlin and the American-European Consensus Conference (AECC) definitions. A Cox proportional hazards model was used to assess the relationship between ARDS and mortality and 6-month Glasgow Outcome Scale (GOS) score.

RESULTS

Two hundred patients were enrolled in the study. Of the patients, 21% (41 of 200) and 26% (52 of 200) developed ARDS using the AECC and Berlin definitions, respectively, with a median time of 3 days (interquartile range, 3) after injury. ARDS by either definition was associated with increased mortality (p = 0.04) but not with differences in functional outcome as measured by the GOS score at 6 months. Adjusted analysis using the Berlin criteria showed an increased mortality associated with ADS (p = 0.01).

CONCLUSION

Severe TBI is associated with an incidence of ARDS ranging from 20% to 25%. The incidence is comparable between the Berlin and AECC definitions. ARDS is associated with increased mortality in severe TBI patients, but further studies are needed to validate these findings.

LEVEL OF EVIDENCE

Epidemiologic study, level II.

Biomarkers improve clinical outcome predictors of mortality following non-penetrating severe traumatic brain injury

OBJECTIVE

This study assessed whether early levels of biomarkers measured in CSF within 24-h of severe TBI would improve the clinical prediction of 6-months mortality.

METHODS

This prospective study conducted at two Level 1 Trauma Centers enrolled adults with severe TBI (GCS ≤8) requiring a ventriculostomy as well as control subjects. Ventricular CSF was sampled within 24-h of injury and analyzed for seven candidate biomarkers (UCH-L1, MAP-2, SBDP150, SBDP145, SBDP120, MBP, and S100B). The International Mission on Prognosis and Analysis of Clinical Trials in TBI (IMPACT) scores (Core, Extended, and Lab) were calculated for each patient to determine risk of 6-months mortality. The IMPACT models and biomarkers were assessed alone and in combination.

RESULTS

There were 152 patients enrolled, 131 TBI patients and 21 control patients. Thirty six (27 %) patients did not survive to 6 months. Biomarkers were all significantly elevated in TBI versus controls (p < 0.001). Peak levels of UCH-L1, SBDP145, MAP-2, and MBP were significantly higher in non-survivors (p < 0.05). Of the seven biomarkers measured at 12-h post-injury MAP-2 (p = 0.004), UCH-L1 (p = 0.024), and MBP (p = 0.037) had significant unadjusted hazard ratios. Of the seven biomarkers measured at the earliest time within 24-h, MAP-2 (p = 0.002), UCH-L1 (p = 0.016), MBP (p = 0.021), and SBDP145 (0.029) had the most significant elevations. When the IMPACT Extended Model was combined with the biomarkers, MAP-2 contributed most significantly to the survival models with sensitivities of 97-100 %.

CONCLUSIONS

These data suggest that early levels of MAP-2 in combination with clinical data provide enhanced prognostic capabilities for mortality at 6 months.

Monitoring biomarkers of cellular injury and death in acute brain injury

BACKGROUND

Molecular biomarkers have revolutionalized diagnosis and treatment of many diseases, such as troponin use in myocardial infarction. Urgent need for high-fidelity biomarkers in neurocritical care has resulted in numerous studies reporting potential candidate biomarkers.

METHODS

We performed an electronic literature search and systematic review of English language articles on cellular/molecular biomarkers associated with outcome and with disease-specific secondary complications in adult patients with acute ischemic stroke (AIS), intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), traumatic brain injury (TBI), and post-cardiac arrest hypoxic ischemic encephalopathic injuries (HIE).

RESULTS

A total of 135 articles were included. Though a wide variety of potential biomarkers have been identified, only neuron-specific enolase has been validated in large cohorts and shows 100% specificity for poor outcome prediction in HIE patients not treated with therapeutic hypothermia. There are many promising candidate blood and CSF biomarkers in SAH, AIS, ICH, and TBI, but none yet meets criteria for routine clinical use.

CONCLUSION

Current studies vary significantly in patient selection, biosample collection/processing, and biomarker measurement protocols, thereby limiting the generalizability of overall results. Future large prospective studies with standardized treatment, biosample collection, and biomarker measurement and validation protocols are necessary to identify high-fidelity biomarkers in neurocritical care.