Management of traumatic brain injury in the intensive care unit

Establishment and validation of prognosis model for patients with cerebral contusion

Background And Objective

Cerebral Contusion (CC) is one of the most serious injury types in patients with traumatic brain injury (TBI). In this study, the baseline data, imaging features and laboratory examinations of patients with CC were summarized and analyzed to develop and validate a prediction model of nomogram to evaluate the clinical outcomes of patients.

Methods

A total of 426 patients with cerebral contusion (CC) admitted to the People’s Hospital of Qinghai Province and Affiliated Hospital of Qingdao University from January 2018 to January 2021 were included in this study, We randomly divided the cohort into a training cohort (n = 284) and a validation cohort (n = 142) with a ratio of 2:1.At Least absolute shrinkage and selection operator (Lasso) regression were used for screening high-risk factors affecting patient prognosis and development of the predictive model. The identification ability and clinical application value of the prediction model were analyzed through the analysis of receiver operating characteristic curve (ROC), calibration curve, and decision curve analysis (DCA).

Results

Twelve independent prognostic factors, including age, Glasgow Coma Score (GCS), Basal cistern status, Midline shift (MLS), Third ventricle status, intracranial pressure (ICP) and CT grade of cerebral edema,etc., were selected by Lasso regression analysis and included in the nomogram. The model showed good predictive performance, with a C index of (0.87, 95% CI, 0.026–0.952) in the training cohort and (0.93, 95% CI, 0.032–0.965) in the validation cohort. Clinical decision curve analysis (DCA) also showed that the model brought high clinical benefits to patients.

Conclusion

This study established a high accuracy of nomogram model to predict the prognosis of patients with CC, its low cost, easy to promote, is especially applicable in the acute environment, at the same time, CSF-glucose/lactate ratio(C-G/L), volume of contusion, and mean CT values of edema zone, which were included for the first time in this study, were independent predictors of poor prognosis in patients with CC. However, this model still has some limitations and deficiencies, which require large sample and multi-center prospective studies to verify and improve our results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02482-4.

A bioimpedance-based monitor for real-time detection and identification of secondary brain injury

Secondary brain injury impacts patient prognosis and can lead to long-term morbidity and mortality in cases of trauma. Continuous monitoring of secondary injury in acute clinical settings is primarily limited to intracranial pressure (ICP); however, ICP is unable to identify essential underlying etiologies of injury needed to guide treatment (e.g. immediate surgical intervention vs medical management). Here we show that a novel intracranial bioimpedance monitor (BIM) can detect onset of secondary injury, differentiate focal (e.g. hemorrhage) from global (e.g. edema) events, identify underlying etiology and provide localization of an intracranial mass effect. We found in an in vivo porcine model that the BIM detected changes in intracranial volume down to 0.38 mL, differentiated high impedance (e.g. ischemic) from low impedance (e.g. hemorrhagic) injuries (p < 0.001), separated focal from global events (p < 0.001) and provided coarse 'imaging' through localization of the mass effect. This work presents for the first time the full design, development, characterization and successful implementation of an intracranial bioimpedance monitor. This BIM technology could be further translated to clinical pathologies including but not limited to traumatic brain injury, intracerebral hemorrhage, stroke, hydrocephalus and post-surgical monitoring.

Xenon treatment after severe traumatic brain injury improves locomotor outcome, reduces acute neuronal loss and enhances early beneficial neuroinflammation: a randomized, blinded, controlled animal study

BACKGROUND

Traumatic brain injury (TBI) is a major cause of morbidity and mortality, but there are no clinically proven treatments that specifically target neuronal loss and secondary injury development following TBI. In this study, we evaluate the effect of xenon treatment on functional outcome, lesion volume, neuronal loss and neuroinflammation after severe TBI in rats.

METHODS

Young adult male Sprague Dawley rats were subjected to controlled cortical impact (CCI) brain trauma or sham surgery followed by treatment with either 50% xenon:25% oxygen balance nitrogen, or control gas 75% nitrogen:25% oxygen. Locomotor function was assessed using Catwalk-XT automated gait analysis at baseline and 24 h after injury. Histological outcomes were assessed following perfusion fixation at 15 min or 24 h after injury or sham procedure.

RESULTS

Xenon treatment reduced lesion volume, reduced early locomotor deficits, and attenuated neuronal loss in clinically relevant cortical and subcortical areas. Xenon treatment resulted in significant increases in Iba1-positive microglia and GFAP-positive reactive astrocytes that was associated with neuronal preservation.

CONCLUSIONS

Our findings demonstrate that xenon improves functional outcome and reduces neuronal loss after brain trauma in rats. Neuronal preservation was associated with a xenon-induced enhancement of microglial cell numbers and astrocyte activation, consistent with a role for early beneficial neuroinflammation in xenon's neuroprotective effect. These findings suggest that xenon may be a first-line clinical treatment for brain trauma.

DNA Methylation Patterns of Chronic Explosive Breaching in U.S. Military Warfighters

Background: Injuries from exposure to explosions rose dramatically during the Iraq and Afghanistan wars, which motivated investigation of blast-related neurotrauma. We have undertaken human studies involving military "breachers" -exposed to controlled, low-level blast during a 3-days explosive breaching course. Methods: We screened epigenetic profiles in peripheral blood samples from 59 subjects (in two separate U.S. Military training sessions) using Infinium MethylationEPIC BeadChips. Participants had varying numbers of exposures to blast over their military careers (empirically defined as high ≥ 40, and conversely, low < 39 breaching exposures). Daily self-reported physiological symptoms were recorded. Tinnitus, memory problems, headaches, and sleep disturbances are most frequently reported. Results: We identified 14 significantly differentially methylated regions (DMRs) within genes associated with cumulative blast exposure in participants with high relative to low cumulative blast exposure. Notably, NTSR1 and SPON1 were significantly differentially methylated in high relative to low blast exposed groups, suggesting that sleep dysregulation may be altered in response to chronic cumulative blast exposure. In comparing lifetime blast exposure at baseline (prior to exposure in current training), and top associated symptoms, we identified significant DMRs associated with tinnitus, sleep difficulties, and headache. Notably, we identified KCNN3, SOD3, MUC4, GALR1, and WDR45B, which are implicated in auditory function, as differentially methylated associated with self-reported tinnitus. These findings suggest neurobiological mechanisms behind auditory injuries in our military warfighters and are particularly relevant given tinnitus is not only a primary disability among veterans, but has also been demonstrated in active duty medical records for populations exposed to blast in training. Additionally, we found that differentially methylated regions associated with the genes CCDC68 and COMT track with sleep difficulties, and those within FMOD and TNXB track with pain and headache. Conclusion: Sleep disturbances, as well as tinnitus and chronic pain, are widely reported in U.S. military service members and veterans. As we have previously demonstrated, DNA methylation encapsulates lifetime exposure to blast. The current data support previous findings and recapitulate transcriptional regulatory alterations in genes involved in sleep, auditory function, and pain. These data uncovered novel epigenetic and transcriptional regulatory mechanism underlying the etiological basis of these symptoms.

Acute and Chronic Molecular Signatures and Associated Symptoms of Blast Exposure in Military Breachers

Injuries from exposure to explosions rose dramatically during the Iraq and Afghanistan wars, which motivated investigations of blast-related neurotrauma and operational breaching. In this study, military “breachers” were exposed to controlled, low-level blast during a 10-day explosive breaching course. Using an omics approach, we assessed epigenetic, transcriptional, and inflammatory profile changes in blood from operational breaching trainees, with varying levels of lifetime blast exposure, along with daily self-reported symptoms (with tinnitus, headaches, and sleep disturbances as the most frequently reported). Although acute exposure to blast did not confer epigenetic changes, specifically in DNA methylation, differentially methylated regions (DMRs) with coordinated gene expression changes associated with lifetime cumulative blast exposures were identified. The accumulative effect of blast showed increased methylation of PAX8 antisense transcript with coordinated repression of gene expression, which has been associated with sleep disturbance. DNA methylation analyses conducted in conjunction with reported symptoms of tinnitus in the low versus high blast incidents groups identified DMRS in KCNE1 and CYP2E1 genes. KCNE1 and CYP2E1 showed the expected inverse correlation between DNA methylation and gene expression, which have been previously implicated in noise-related hearing loss. Although no significant transcriptional changes were observed in samples obtained at the onset of the training course relative to chronic cumulative blast, we identified a large number of transcriptional perturbations acutely pre- versus post-blast exposure. Acutely, 67 robustly differentially expressed genes (fold change ≥1.5), including UFC1 and YOD1 ubiquitin-related proteins, were identified. Inflammatory analyses of cytokines and chemokines revealed dysregulation of MCP-1, GCSF, HGF, MCSF, and RANTES acutely after blast exposure. These data show the importance of an omics approach, revealing that transcriptional and inflammatory biomarkers capture acute low-level blast overpressure exposure, whereas DNA methylation marks encapsulate chronic long-term symptoms.

Management of moderate and severe traumatic brain injury

Traumatic brain injury (TBI) is a common disorder with high morbidity and mortality, accounting for one in every three deaths due to injury. Older adults are especially vulnerable. They have the highest rates of TBI-related hospitalization and death. There are about 2.5 to 6.5 million US citizens living with TBI-related disabilities. The cost of care is very high. Aside from prevention, little can be done for the initial primary injury of neurotrauma. The tissue damage incurred directly from the inciting event, for example, a blow to the head or bullet penetration, is largely complete by the time medical care can be instituted. However, this event will give rise to secondary injury, which consists of a cascade of changes on a cellular and molecular level, including cellular swelling, loss of membrane gradients, influx of immune and inflammatory mediators, excitotoxic transmitter release, and changes in calcium dynamics. Clinicians can intercede with interventions to improve outcome in the mitigating secondary injury. The fundamental concepts in critical care management of moderate and severe TBI focus on alleviating intracranial pressure and avoiding hypotension and hypoxia. In addition to these important considerations, mechanical ventilation, appropriate transfusion of blood products, management of paroxysmal sympathetic hyperactivity, using nutrition as a therapy, and, of course, venous thromboembolism and seizure prevention are all essential in the management of moderate to severe TBI patients. These concepts will be reviewed using the recent 2016 Brain Trauma Foundation Guidelines to discuss best practices and identify future research priorities.

Neuroimaging of deployment-associated traumatic brain injury (TBI) with a focus on mild TBI (mTBI) since 2009

OBJECTIVES

A substantial body of recent research has aimed to better understand the clinical sequelae of military trauma through the application of advanced brain imaging procedures in Veteran populations. The primary objective of this review was to highlight a portion of these recent studies to demonstrate how imaging tools can be used to understand military-associated brain injury.

METHODS

We focus here on the phenomenon of mild traumatic brain injury (mTBI) given its high prevalence in the Veteran population and current recognition of the need to better understand the clinical implications of this trauma. This is intended to provide readers with an initial exposure to the field of neuroimaging of mTBI with a brief introduction to the concept of traumatic brain injury, followed by a summary of the major imaging techniques that have been applied to the study of mTBI.

RESULTS

Taken together, the collection of studies reviewed demonstrates a clear role for neuroimaging towards understanding the various neural consequences of mTBI as well as the clinical complications of such brain changes.

CONCLUSIONS

This information must be considered in the larger context of research into mTBI, including the potentially unique nature of blast exposure and the long-term consequences of mTBI.

Association between continuous peripheral i.v. infusion of 3% sodium chloride injection and phlebitis in adults

PURPOSE

One institution's experience with use of peripheral i.v. (PIV) catheters for prolonged infusions of 3% sodium chloride injection at rates up to 100 mL/hr is described.

METHODS

A prospective, observational, 13-month quality assurance project was conducted at an academic medical center to evaluate frequencies of patient and catheter phlebitis among adult inpatients who received both an infusion of 3% sodium chloride injection for a period of ≥4 hours through a dedicated PIV catheter and infusions of routine-care solutions (RCSs) through separate PIV catheters during the same hospital stay.

RESULTS

Sixty patients received PIV infusions through a total of 291 catheters during the study period. The majority of patients (78%) received infusions of 3% sodium chloride injection for intracranial hypertension, with 30% receiving such infusions in the intensive care unit. Phlebitis occurred in 28 patients (47%) during infusions of 3% sodium chloride and 26 patients (43%) during RCS infusions (p = 0.19). Catheter phlebitis occurred in 73 catheters (25%), with no significant difference in the frequencies of catheter phlebitis with infusion of 3% sodium chloride versus RCSs (30% [32 of 106 catheters]) versus 22% [41 of 185 catheters]), p = 0.16).

CONCLUSION

Patient and catheter phlebitis rates were not significantly different with infusions of 3% sodium chloride injection versus RCSs, suggesting that an osmolarity cutoff value of 900 mOsm/L for peripheral infusions of hypertonic saline solutions may not be warranted.

Cerebrovascular Protective Effect of Boldine Against Neural Apoptosis via Inhibition of Mitochondrial Bax Translocation and Cytochrome C Release

BACKGROUND In the present study, we explored the protective effect and mechanism of action of boldine (BOL) against neural apoptosis, which is a mediator of TBI. MATERIAL AND METHODS The effect of BOL on mitochondrial and cytosol proteins of extracted from cerebral cortical tissue of mice was evaluated. The grip test was used to assess the neurological deficit and brain water content of the subjects after administration of BOL to assess its effect on SOD, GSH, and MDA activity in brain ischemic tissues. To further confirm the effect of the BOL, the histopathological analysis and morphology of neurons were studied by Nissl staining. The effect of BOL against TBI-induced neural apoptosis by immuno-histochemistry and Western blotting assay were also studied. RESULTS BOL showed significant improvement against TBI in a dose-dependent manner. In the BOL-treated group, the apoptotic index was significantly reduced, but the level of caspase-3 was greatly diminished. Additionally, the level of the Bax in mitochondria (mit) and cytosol was elevated in the TBI-treated group as compared to the sham group. Further BOL at the test dose causes significant reduction in the level of mitochondrial MDA together with increase in SOD activity as compared to the TBI alone group. CONCLUSIONS BOL showed a cerebroprotective effect against TBI by attenuating the oxidative stress and the mitochondrial apoptotic pathway. It also inhibited mitochondrial Bax translocation and cytochrome c release.

[A new concept of organization and scope of neurosurgical care in the US army during armed conflicts in the early 2000s]

Military operations in various parts of the world in the early 2000s are becoming more regionalized; new warfare tactics emerge, which makes it necessary to review and modify the neurosurgical care system. The article reviews the results of original studies on this issue and summarizes the experience of the US Army medical service in Afghanistan and Iraq. The article discusses the structure of sanitary losses, organization and scope of medical and evacuation neurosurgical measures, types and techniques of surgical interventions, and the rate of complications. We describe five levels of neurosurgical care echelons and an implemented "injury control - neurosurgery" concept; particular attention is paid to the peculiarities of research and specialist training. We demonstrate that implementation of the new concept for organization and scope of neurosurgical care has improved treatment outcomes and reduced the mortality rate in the mentioned military conflicts of recent years compared to those in the Vietnam War. We may conclude that the described experience of the US Army can be used to improve the efficacy of neurosurgical care to the wounded and victims of armed conflicts.

What Definition Is Used to Describe Second Impact Syndrome in Sports? A Systematic and Critical Review

Concern about what has been termed, "second impact syndrome" (SIS) is a major factor determining return-to-play decisions after concussion. However, definitions of SIS vary. We used Scopus to conduct a systematic review and categorize the definitions used to describe SIS. Of the 91 sources identified, 79 (87%) clearly specified that SIS involved either cerebral edema or death after a concussion when a prior concussion had not resolved. Twelve articles (13%) could be interpreted as merely the events of two consecutive concussions. Among the articles that listed mortality rates, nearly all (33/35, 94%) said the rate of death was "high" (e.g., 50% to 100%). Our review found that most articles define SIS as a syndrome requiring catastrophic brain injury after consecutive concussive episodes. Given that it is unclear how common it is to have a second concussion while not fully recovered from a first concussion, the actual mortality rate of SIS is unknown.

Bench-to-Bedside and Bedside Back to the Bench; Seeking a Better Understanding of the Acute Pathophysiological Process in Severe Traumatic Brain Injury

Despite substantial investments, traumatic brain injury (TBI) remains one of the major disorders that lack specific pharmacotherapy. To a substantial degree, this situation is due to lack of understanding of the pathophysiological process of the disease. Experimental TBI research offers controlled, rapid, and cost-effective means to identify the pathophysiology but translating experimental findings into clinical practice can be further improved by using the same or similar outcome measures and clinically relevant time points. The pathophysiology during the acute phase of severe TBI is especially poorly understood. In this Mini review, I discuss some of the incongruences between current clinical practices and needs versus information provided by experimental TBI research as well as the benefits of designing animal experiments with translation into clinical practice in mind.

Factors prognosticating the outcome of decompressive craniectomy in severe traumatic brain injury: A Malaysian experience

Objective:

The objective of this prospective cohort study was to analyse the characteristics of severe Traumatic Brain Injury (TBI) in a regional trauma centre Hospital Kuala Lumpur (HKL) along with its impact of various prognostic factors post Decompressive Craniectomy (DC).

Materials and Methods:

Duration of the study was of 13 months in HKL. 110 consecutive patients undergoing DC and remained in our centre were recruited. They were then analysed categorically with standard analytical software.

Results:

Age group have highest range between 12-30 category with male preponderance. Common mechanism of injury was motor vehicle accident involving motorcyclist. Univariate analysis showed statistically significant in referral area (P = 0.006). In clinical evaluation statistically significant was the motor score (P = 0.040), pupillary state (P = 0.010), blood pressure stability (P = 0.013) and evidence of Diabetes Insipidus (P < 0.001). In biochemical status the significant statistics included evidence of coagulopathy (P < 0.001), evidence of acidosis (P = 0.003) and evidence of hypoxia (P = 0.030). In Radiological sector, significant univariate analysis proved in location of the subdural clot (P < 0.010), location of the contusion (P = 0.045), site of existence of both type of clots (P = 0.031) and the evidence of edema (P = 0.041). The timing of injury was noted to be significant as well (P = 0.061). In the post operative care was, there were significance in the overall stability in intensive care (P < 0.001), the stability of blood pressure, cerebral perfusion pressure, pulse rates and oxygen saturation (all P < 0.001)seen individually, post operative ICP monitoring in the immediate (P = 0.002), within 24 hours (P < 0.001) and within 24-48 hours (P < 0.001) period, along with post operative pupillary size (P < 0.001) and motor score (P < 0.001). Post operatively, radiologically significant statistics included evidence of midline shift post operatively in the CT scan (P < 0.001). Multivariate logistic regression with stepwise likelihood ratio (LR) method concluded that hypoxia post operatively (P = 0.152), the unmaintained Cerebral Perfusion Pressure (CPP) (P = 0.007) and unstable blood pressure (BP) (P = <0.001). Poor outcome noted 10.2 times higher in post operative hypoxia [OR10.184; 95% CI: 0.424, 244.495]. Odds of having poor outcome if CPP unmaintained was 13.8 times higher [OR: 13.754; CI: 2.050, 92.301]. Highest predictor of poor outcome was the unstable BP, 32 times higher [OR 31.600; CI: 4.530, 220440].

Conclusion:

Our series represent both urban and rural population, noted to be the largest series in severe TBI in this region. Severe head injury accounts for significant proportion of neurosurgical admissions, resources with its impact on socio-economic concerns to a growing population like Malaysia. This study concludes that the predictors of outcome in severe TBI post DC were postoperative hypoxia, unmaintained cerebral perfusion pressure and unstable blood pressure as independent predictors of poor outcome. Key words: Decompressive craniectomy, prognostication of decompressive craniectomy, prognostication of severe head injury, prognostication of traumatic brain injury, severe head injury, severe traumatic brain injury, traumatic brain injury.

Continuous measurement of the cumulative amplitude and duration of hyperglycemia best predicts outcome after traumatic brain injury

BACKGROUND

This study aimed to assess the accuracy and utility of high-resolution continuous glucose recording in patients with traumatic brain injury (TBI) and to establish whether a relationship exists between the cumulative amplitude and duration of hyperglycemia and outcome after TBI.

METHODS

Glucose data for 56 TBI patients were collected continuously at 5-min intervals. The degree and duration of hyperglycemia above treatment thresholds were calculated as "glucose times time dose" (GTD; mg/dL d) using continuous recordings (GTD) for early stage (first 3 days). Long-term neurological functional outcome was assessed using the extended Glasgow Outcome Scale (GOSE). Receiver operating characteristic (ROC) curves were constructed to determine the predictive values of GTD, percentage readings, mean, and range of glucose for in-hospital mortality and GOSE.

RESULTS

All measurements of GTD were statistically significantly higher in the group that died. GTD of glucose >150 and glucose >180 had a high-predictive power for in-hospital mortality (areas under the ROC curve [AUC] = 0.917; 95 % CI, 0.837-0.998 and 0.876; 95 % CI, 0.784-0.967, respectively) and demonstrated significantly higher predictive power for mortality when compared with %reading >150 and %reading >180, respectively (p < 0.05). GTD of glucose >150 also had a significantly higher predictive power for mortality than mean glucose and range of glucose. GTD of glucose >150 and glucose >180 also had a high-predictive power for poor outcome (areas under the ROC curve [AUC] = 0.913; 95 % CI, 0.843-0.983 and 0.858; 95 % CI, 0.760-0.956, respectively).

CONCLUSIONS

Continuous collection of glucose recordings is more reliable and accurate than routine discontinuous recordings. Assessing both the duration and the amplitude of the episodes using continuous collection of glucose data helps in better predicting outcomes than the total duration of episodes.

Brain injury from explosive blast: description and clinical management

Accumulating clinical experience is indicating that explosive blast brain injury is becoming recognized as a disease distinct from the penetrating form of blast injury as well as the classic closed head injury (CHI). In recent US conflicts in Iraq and Afghanistan, over 60% of combat casualties were from explosive blast with the hallmark explosive weapon being the improvised explosive device (IED). Explosive blast TBI is a condition afflicting many combat injured warfighters potentially constituting another category of TBI. Clinically, it shares many features with conventional TBI but possesses some unique aspects. In its mild form, it also shares many clinical features with PTSD but here again has distinct aspects. Although military medical providers depend on civilian standard of care guidelines when managing explosive blast mTBI, they are continually adapting their medical practice in order to optimize the treatment of this disease, particularly in a theater of war. It is clear that further rigorous scientific study of explosive blast mTBI at both the basic science and clinical levels is needed. This research must include improved understanding of the causes and mechanisms of explosive blast TBI as well as comprehensive epidemiologic studies to determine the prevalence of this disease and its risk factors. A widely accepted unambiguous clinical description of explosive blast mTBI with diagnostic criteria would greatly improve diagnosis. It is hoped that through appropriate research meaningful prevention, mitigation, and treatment strategies for explosive blast mTBI can be speedily realized.

Long-Term Comparison of GOS-E Scores in Patients Treated With Phenytoin or Levetiracetam for Posttraumatic Seizure Prophylaxis After Traumatic Brain Injury

Background: Much debate exists on the optimal medication for posttraumatic seizure prophylaxis after traumatic brain injury (TBI). There is some evidence that levetiracetam (LEV) could be neuroprotective and provide long-term benefits in this patient population. Objective: The primary objective was to compare the Glasgow Outcome Scale–Extended (GOS-E) 6 months or more after severe TBI. Secondary end points were presence of early seizures (0 to 7 days post-TBI) or late seizures (8 days post-TBI to phone interview), use of anticonvulsant medication when interviewed, medication-related hospital complications, and a summary of phenytoin (PHT) and LEV dosing regimens. Methods: This was an IRB-approved, single-center, prospective cohort analysis. Patients were identified by cross-referencing a list of patients receiving LEV or PHT, with a list of patients with ICD-9 code consistent with TBI. After study inclusion, patients were contacted by telephone, and the GOS-E was administered. Data for secondary end points were gathered by retrospective chart review. Results: In all, 19 patients were included in the final analysis. There was no difference in the GOS-E score assessed ≥6 months after injury (5.07 ± 1.69 vs 5.60 ± 2.07, P = 0.58). There was no difference in the secondary end points of early seizures ( P = 0.53) or late seizures ( P = 0.53). However, the PHT group experienced a higher rate of hospital days with recorded fever (0.20 ± 0.22 vs 0 ± 0; P = 0.014). Conclusions: Long-term functional outcome in patients who experienced a TBI was not affected by treatment with PHT or LEV; however, patients treated with PHT had a higher incidence of fever during hospitalization.

Unexpected recovery of function after severe traumatic brain injury: the limits of early neuroimaging-based outcome prediction

BACKGROUND

Prognostication in the early stage of traumatic coma is a common challenge in the neuro-intensive care unit. We report the unexpected recovery of functional milestones (i.e., consciousness, communication, and community reintegration) in a 19-year-old man who sustained a severe traumatic brain injury. The early magnetic resonance imaging (MRI) findings, at the time, suggested a poor prognosis.

METHODS

During the first year of the patient's recovery, MRI with diffusion tensor imaging and T2*-weighted imaging was performed on day 8 (coma), day 44 (minimally conscious state), day 198 (post-traumatic confusional state), and day 366 (community reintegration). Mean apparent diffusion coefficient (ADC) and fractional anisotropy values in the corpus callosum, cerebral hemispheric white matter, and thalamus were compared with clinical assessments using the Disability Rating Scale (DRS).

RESULTS

Extensive diffusion restriction in the corpus callosum and bihemispheric white matter was observed on day 8, with ADC values in a range typically associated with neurotoxic injury (230-400 × 10(-6 )mm(2)/s). T2*-weighted MRI revealed widespread hemorrhagic axonal injury in the cerebral hemispheres, corpus callosum, and brainstem. Despite the presence of severe axonal injury on early MRI, the patient regained the ability to communicate and perform activities of daily living independently at 1 year post-injury (DRS = 8).

CONCLUSIONS

MRI data should be interpreted with caution when prognosticating for patients in traumatic coma. Recovery of consciousness and community reintegration are possible even when extensive traumatic axonal injury is demonstrated by early MRI.

Neuroprotection against Traumatic Brain Injury by Xenon, but Not Argon, Is Mediated by Inhibition at the N-Methyl-d-Aspartate Receptor Glycine Site

Background:

Xenon, the inert anesthetic gas, is neuroprotective in models of brain injury. The authors investigate the neuroprotective mechanisms of the inert gases such as xenon, argon, krypton, neon, and helium in an in vitro model of traumatic brain injury.

Methods:

The authors use an in vitro model using mouse organotypic hippocampal brain slices, subjected to a focal mechanical trauma, with injury quantified by propidium iodide fluorescence. Patch clamp electrophysiology is used to investigate the effect of the inert gases on N-methyl-d-aspartate receptors and TREK-1 channels, two molecular targets likely to play a role in neuroprotection.

Results:

Xenon (50%) and, to a lesser extent, argon (50%) are neuroprotective against traumatic injury when applied after injury (xenon 43 ± 1% protection at 72 h after injury [N = 104]; argon 30 ± 6% protection [N = 44]; mean ± SEM). Helium, neon, and krypton are devoid of neuroprotective effect. Xenon (50%) prevents development of secondary injury up to 48 h after trauma. Argon (50%) attenuates secondary injury, but is less effective than xenon (xenon 50 ± 5% reduction in secondary injury at 72 h after injury [N = 104]; argon 34 ± 8% reduction [N = 44]; mean ± SEM). Glycine reverses the neuroprotective effect of xenon, but not argon, consistent with competitive inhibition at the N-methyl-d-aspartate receptor glycine site mediating xenon neuroprotection against traumatic brain injury. Xenon inhibits N-methyl-d-aspartate receptors and activates TREK-1 channels, whereas argon, krypton, neon, and helium have no effect on these ion channels.

Conclusions:

Xenon neuroprotection against traumatic brain injury can be reversed by increasing the glycine concentration, consistent with inhibition at the N-methyl-d-aspartate receptor glycine site playing a significant role in xenon neuroprotection. Argon and xenon do not act via the same mechanism.

Management of intracerebral pressure in the neurosciences critical care unit

Management of intracranial pressure in neurocritical care remains a potentially valuable target for improvements in therapy and patient outcomes. Surrogate markers of increased intracranial pressure, invasive monitors, and standard therapy, as well as promising new approaches to improve cerebral compliance are discussed, and a current review of the literature addressing this metric in neuroscience critical care is provided.

Traumatic brain injury: pathophysiology, monitoring, and mechanism-based care

Traumatic brain injury, which may be blunt or penetrating, begins altering intracranial physiology at the moment of impact as primary brain trauma. This article differentiates blunt versus penetrating brain trauma, primary versus secondary brain injury, and subsequent intracranial pathophysiology. Discussion and case study correlate intracranial pathophysiology and multisystem influences on evolving brain injury with mechanism-based interventions to modulate brain components (brain, blood, and cerebrospinal fluid volumes). The discussion also explores the effects of controlled ventilation, cardiopulmonary physiology, and global physiologic state on secondary injury, control of intracranial pressure, and recovery.

Neurology and the military: Five new things

The current Iraq and Afghanistan conflicts have seen the highest survival rates in US service members ever, despite staggering numbers of traumatic brain injury and limb loss cases. The improvement in survival can be attributed at least in part to advances in far-forward, rapid medical treatment, including the administration of hypertonic saline solutions and decompressive craniectomies to manage elevated intracranial pressure. After evacuation to military hospitals in the continental United States, service members who have had limb loss face extensive rehabilitation. The growing amputee population has led to a burgeoning interest in the treatment of phantom limb pain and in the development of advanced prostheses.

Therapeutic use of omega-3 fatty acids in severe head trauma

Traumatic brain injury (TBI) has long been recognized as the leading cause of traumatic death and disability. Tremendous advances in surgical and intensive care unit management of the primary injury, including maintaining adequate oxygenation, controlling intracranial pressure, and ensuring proper cerebral perfusion pressure, have resulted in reduced mortality. However, the secondary injury phase of TBI is a prolonged pathogenic process characterized by neuroinflammation, excitatory amino acids, free radicals, and ion imbalance. There are no approved therapies to directly address these underlying processes. Here, we present a case that was intentionally treated with substantial amounts of omega-3 fatty acids (n-3FA) to provide the nutritional foundation for the brain to begin the healing process following severe TBI. Recent animal research supports the use of n-3FA, and clinical experience suggests that benefits may be possible from substantially and aggressively adding n-3FA to optimize the nutritional foundation of severe TBI patients and must be in place if the brain is to be given the opportunity to repair itself to the best possible extent. Administration early in the course of treatment, in the emergency department or sooner, has the potential to improve outcomes from this potentially devastating public health problem.

Serum-based protein biomarkers in blast-induced traumatic brain injury spectrum disorder

The biological consequences of exposure to explosive blast are extremely complex. Serum protein biomarkers in blast-induced traumatic brain injury (bTBI) can aid in determining injury severity, monitoring progress, and predicting outcome. Exposure to blast results in varying degrees of physical injury. Explosive blast can also induce psychological stress that can contribute to or amplify the extent of physical damage. Given the complexity, scale of injury, and variety of symptoms, bTBI may be best described as a spectrum disorder. In this focused review, we summarize the status of serum protein biomarkers in bTBI in the context of the classification and pathological changes of other forms of TBI. Finally, we recommend specific and easily implementable measures to accelerate serum protein biomarker discovery and validation in bTBI.

Glucose variability negatively impacts long-term functional outcome in patients with traumatic brain injury

PURPOSE

Significant glycemic excursions (so-called glucose variability) affect the outcome of generic critically ill patients but has not been well studied in patients with traumatic brain injury (TBI). The purpose of this study was to evaluate the impact of glucose variability on long-term functional outcome of patients with TBI.

MATERIAL AND METHODS

A noncomputerized tight glucose control protocol was used in our intensivist model surgical intensive care unit. The relationship between the glucose variability and long-term (a median of 6 months after injury) functional outcome defined by extended Glasgow Outcome Scale (GOSE) was analyzed using ordinal logistic regression models. Glucose variability was defined by SD and percentage of excursion (POE) from the preset range glucose level.

RESULTS

A total of 109 patients with TBI under tight glucose control had long-term GOSE evaluated. In univariable analysis, there was a significant association between lower GOSE score and higher mean glucose, higher SD, POE more than 60, POE 80 to 150, and single episode of glucose less than 60 mg/dL but not POE 80 to 110. After adjusting for possible confounding variables in multivariable ordinal logistic regression models, higher SD, POE more than 60, POE 80 to 150, and single episode of glucose less than 60 mg/dL were significantly associated with lower GOSE score.

CONCLUSIONS

Glucose variability was significantly associated with poorer long-term functional outcome in patients with TBI as measured by the GOSE score. Well-designed protocols to minimize glucose variability may be key in improving long-term functional outcome.

Delayed detection of carotid-cavernous fistulas associated with wartime blast-induced craniofacial trauma

Blast-induced neurotrauma is a leading cause of military casualties. Its effects on cerebrovascular structures are not well understood. Vascular injury resulting from overpressure shock wave impact may have a delayed presentation and detection. The authors present the cases of 2 patients who sustained blast-induced craniofacial trauma and brain injury. Detection of a cervical dissection was delayed in one patient, and detection of carotid-cavernous fistulas was delayed in both patients. The authors report the successful obliteration of both the dissection and the carotidcavernous fistulas via an endovascular approach. Endovascular management provides both a reasonable and effective therapeutic option to blast-induced cerebrovascular injuries.

Surgical innovations arising from the Iraq and Afghanistan wars

The delivery of combat casualty care poses numerous challenges including austere conditions, limited supplies and medical personnel, and multiple simultaneous patients. However, the exigent circumstances of the battlefield compel the development of research and the advancement of adaptive, practical medical technologies to support and sustain military health. In Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF), modern changes in medical management, coupled with improved protective gear and evacuation capabilities, have facilitated the highest survival rate in combat history.

Explosive blast neurotrauma

Explosive blast traumatic brain injury (TBI) is one of the more serious wounds suffered by United States service members injured in the current conflicts in Iraq and Afghanistan. Some military medical treatments for blast TBI that have been introduced successfully in the war theater include decompressive craniectomy, cerebral angiography, transcranial Doppler, hypertonic resuscitation fluids, among others. Stateside neurosurgery, neuro-critical care, and rehabilitation for these patients have similarly progressed. With experience, military physicians have been able to clinically describe blast TBI across the entire severity spectrum. One important clinical finding is that a significant number of severe blast TBI victims develop pseudoaneurysms and vasospasm, which can lead to delayed decompensation. Another is that mild blast TBI shares clinical features with post-traumatic stress disorder (PTSD). Observations suggest that the mechanism by which explosive blast injures the central nervous system may be more complex than initially assumed. Rigorous study at the basic science and clinical levels, including detailed biomechanical analysis, is needed to improve understanding of this disease. A comprehensive epidemiological study is also warranted to determine the prevalence of this disease and the factors that contribute most to the risk of developing it. Sadly, this military-specific disease has significant potential to become a civilian one as well.

Neuromodulation on cervical spinal cord combined with hyperbaric oxygen in comatose patients--a preliminary report

BACKGROUND

Because both SCS and HBO therapy have shown some promise in treating patients with states of reduced consciousness, we evaluated the combination of therapies in a prospective trial in comatose patients.

METHODS

Twelve patients who had received median nerve stimulation for 3 months without improvement in consciousness received cSCS for 1 year combined with simultaneous HBO therapy for the first 3 months. Another group enrolled 12 patients who received median nerve stimulation only were served as control.

RESULTS

Six patients emerged from coma at 1 year (after conclusion of treatment). Glasgow Coma Scale score, SPECT imaging, and PVS scores (state and reaction subscores) of the 12 patients were all significantly increased at 1 year compared with enrollment (P < .05). Neither respirator nor tracheostomy was needed to assist respiration in any patient. Only 1 of 12 patients still needed nasogastric tube feeding at 1 year. By contrast, control patients (without cSCS and HBO therapy) showed no apparent improvement.

CONCLUSION

Increase of GCS score, cerebral blood perfusion, and PVS scores were observed in comatose patients treated with combined cSCS and HBO therapy.