Head injury

Cranial Nerve II–VII Injuries in Fatal Closed Head Trauma

PURPOSE

To study the distribution and mechanism of traumatic injuries to the nerves supplying the eye and muscles protecting the visual apparatus.

METHODS

Brain autopsy was carried out in 12 consecutive patients who died within three days after closed head injury. A segment of the brainstem with the entire intracranial portion of nerves II-VII was dissected out in each case and fixed in formalin. The specimens were stripped of the leptomeninges and inspected thoroughly under magnification.

RESULTS

Injuries to the nerves were seen in nine subjects. The oculomotor nerve was completely torn off from the midbrain unilaterally in three and bilaterally in two cases. In one patient only a portion of the superficial fibres on the medial aspect of the nerve was ripped out from the brainstem. In two patients the fourth nerve was ruptured. The root of the fifth cranial nerve was contused and the fibres between the brainstem and Gasserian ganglion crushed and separated in one case. Bilateral avulsion of the root of the sixth nerve from the brainstem was found in two cases. The initial segment of the facial nerve was crushed in two subjects. No visible injury to the optic nerves was found.

CONCLUSIONS

Cranial nerves related to the visual system are subject to serious injury in a large proportion of cases of severe head trauma resulting from automobile accidents. In the majority of cases damage results from ripping the roots of these nerves out of the brainstem.

Twelve-month recovery of medical decision-making capacity following traumatic brain injury

OBJECTIVE

To investigate recovery of medical decision-making capacity (MDC) over the first year following traumatic brain injury (TBI).

METHODS

A total of 177 participants (111 persons with TBI and 66 healthy controls) were recruited from an inpatient/outpatient TBI rehabilitation unit and outpatient neurology department. Participants with TBI were classified by injury severity into subgroups: mild TBI (mTBI; n = 28), complicated mild TBI (cmTBI; n = 23), and moderate/severe TBI (msevTBI; n = 60). Control and TBI groups were compared at 1 month (t1), 6 months (t2), and 12 months (t3) postinjury using the Capacity to Consent to Treatment Instrument (CCTI), which evaluates MDC using 5 consent standards: expressing choice, reasonable choice, appreciation, reasoning, and understanding.

RESULTS

Relative to controls, no TBI group displayed impairment on CCTI expressing choice or reasonable choice at any timepoint. Those with mTBI had reduced appreciation and understanding at t1, which resolved by t2. The cmTBI and msevTBI groups were impaired on all 3 complex consent standards at t1. While patients with cmTBI improved to a level similar to controls by t3, those with msevTBI remained impaired on reasoning and understanding. Across all TBI groups, notable MDC improvement only occurred over the first 6 months postinjury.

CONCLUSIONS

Over 1 year, most individuals with mTBI or cmTBI regain MDC, while many individuals with msevTBI have lingering deficits in reasoning and comprehension of treatment information. Clinical recovery of MDC occurs primarily during the first 6 months post-TBI regardless of injury severity. Clinicians can therefore identify MDC outcomes in TBI at 6 months postinjury.

Automated monitoring of early neurobehavioral changes in mice following traumatic brain injury

Traumatic brain injury often causes a variety of behavioral and emotional impairments that can develop into chronic disorders. Therefore, there is a need to shift towards identifying early symptoms that can aid in the prediction of traumatic brain injury outcomes and behavioral endpoints in patients with traumatic brain injury after early interventions. In this study, we used the SmartCage system, an automated quantitative approach to assess behavior alterations in mice during an early phase of traumatic brain injury in their home cages. Female C57BL/6 adult mice were subjected to moderate controlled cortical impact (CCI) injury. The mice then received a battery of behavioral assessments including neurological score, locomotor activity, sleep/wake states, and anxiety-like behaviors on days 1, 2, and 7 after CCI. Histological analysis was performed on day 7 after the last assessment. Spontaneous activities on days 1 and 2 after injury were significantly decreased in the CCI group. The average percentage of sleep time spent in both dark and light cycles were significantly higher in the CCI group than in the sham group. For anxiety-like behaviors, the time spent in a light compartment and the number of transitions between the dark/light compartments were all significantly reduced in the CCI group than in the sham group. In addition, the mice suffering from CCI exhibited a preference of staying in the dark compartment of a dark/light cage. The CCI mice showed reduced neurological score and histological abnormalities, which are well correlated to the automated behavioral assessments. Our findings demonstrate that the automated SmartCage system provides sensitive and objective measures for early behavior changes in mice following traumatic brain injury.

Secondary stroke in patients with polytrauma and traumatic brain injury treated in an Intensive Care Unit, Karlovac General Hospital, Croatia

Traumatic brain injury (TBI) is divided into primary and secondary brain injury. Primary brain injury occurs at the time of injury and is the direct consequence of kinetic energy acting on the brain tissue. Secondary brain injury occurs several hours or days after primary brain injury and is the result of factors including shock, systemic hypotension, hypoxia, hypothermia or hyperthermia, intracranial hypertension, cerebral oedema, intracranial bleeding or inflammation. The aim of this retrospective analysis of a prospective database was to determine the prevalence of secondary stroke and stroke-related mortality, causes of secondary stroke, treatment and length of stay in the ICU and hospital. This study included patients with TBI with or without other injuries who were hospitalised in a general ICU over a five-year period. The following parameters were assessed: demographics (age, sex), scores (Glasgow Coma Score, APACHE II, SOFA), secondary stroke (prevalence, time of occurrence after primary brain injury, causes of stroke and associated mortality), length of stay in the ICU and hospital, vital parameters (state of consciousness, cardiac function, respiration, circulation, thermoregulation, diuresis) and laboratory values (leukocytes, C-reactive protein [CRP], blood glucose, blood gas analysis, urea, creatinine). Medical data were analysed for 306 patients with TBI (median age 56 years, range 18-93 years) who were treated in the general ICU. Secondary stroke occurred in 23 patients (7.5%), 10 of whom died, which gives a mortality rate of 43.4%. Three patients were excluded as the cause of the injury was missile trauma. The study data indicate that inflammation is the most important cause of secondary insults. Levels of CRP were elevated in 65% of patients with secondary brain injury; leukocytosis was present in 87% of these patients, and blood glucose was elevated in 73%. The lungs and urinary tract were the most common sites of infection. In conclusion, elevated inflammatory markers (white blood cell count and CRP) and hyperglycaemia are associated with secondary brain injury. The lack of routine use of intracranial pressure (ICP) monitoring may explain the high mortality rate and the occurrence of secondary stroke in patients with TBI.

Molecular programs induced by heat acclimation confer neuroprotection against TBI and hypoxic insults via cross-tolerance mechanisms

Neuroprotection following prolonged exposure to high ambient temperatures (heat acclimation HA) develops via altered molecular programs such as cross-tolerance Heat Acclimation-Neuroprotection Cross-Tolerance (HANCT). The mechanisms underlying cross-tolerance depend on enhanced "on-demand" protective pathways evolving during acclimation. The protection achieved is long lasting and limits the need for de novo recruitment of cytoprotective pathways upon exposure to novel stressors. Using mouse and rat acclimated phenotypes, we will focus on the impact of heat acclimation on Angiotensin II-AT2 receptors in neurogenesis and on HIF-1 as key mediators in spontaneous recovery and HANCT after traumatic brain injury (TBI). The neuroprotective consequences of heat acclimation on NMDA and AMPA receptors will be discussed using the global hypoxia model. A behavioral-molecular link will be crystallized. The differences between HANCT and consensus preconditioning will be reviewed.

Activation of the kynurenine pathway and increased production of the excitotoxin quinolinic acid following traumatic brain injury in humans

Abstract

During inflammation, the kynurenine pathway (KP) metabolises the essential amino acid tryptophan (TRP) potentially contributing to excitotoxicity via the release of quinolinic acid (QUIN) and 3-hydroxykynurenine (3HK). Despite the importance of excitotoxicity in the development of secondary brain damage, investigations on the KP in TBI are scarce. In this study, we comprehensively characterised changes in KP activation by measuring numerous metabolites in cerebrospinal fluid (CSF) from TBI patients and assessing the expression of key KP enzymes in brain tissue from TBI victims. Acute QUIN levels were further correlated with outcome scores to explore its prognostic value in TBI recovery.

Methods

Twenty-eight patients with severe TBI (GCS ≤ 8, three patients had initial GCS = 9–10, but rapidly deteriorated to ≤8) were recruited. CSF was collected from admission to day 5 post-injury. TRP, kynurenine (KYN), kynurenic acid (KYNA), QUIN, anthranilic acid (AA) and 3-hydroxyanthranilic acid (3HAA) were measured in CSF. The Glasgow Outcome Scale Extended (GOSE) score was assessed at 6 months post-TBI. Post-mortem brains were obtained from the Australian Neurotrauma Tissue and Fluid Bank and used in qPCR for quantitating expression of KP enzymes (indoleamine 2,3-dioxygenase-1 (IDO1), kynurenase (KYNase), kynurenine amino transferase-II (KAT-II), kynurenine 3-monooxygenase (KMO), 3-hydroxyanthranilic acid oxygenase (3HAO) and quinolinic acid phosphoribosyl transferase (QPRTase) and IDO1 immunohistochemistry.

Results

In CSF, KYN, KYNA and QUIN were elevated whereas TRP, AA and 3HAA remained unchanged. The ratios of QUIN:KYN, QUIN:KYNA, KYNA:KYN and 3HAA:AA revealed that QUIN levels were significantly higher than KYN and KYNA, supporting increased neurotoxicity. Amplified IDO1 and KYNase mRNA expression was demonstrated on post-mortem brains, and enhanced IDO1 protein coincided with overt tissue damage. QUIN levels in CSF were significantly higher in patients with unfavourable outcome and inversely correlated with GOSE scores.

Conclusion

TBI induced a striking activation of the KP pathway with sustained increase of QUIN. The exceeding production of QUIN together with increased IDO1 activation and mRNA expression in brain-injured areas suggests that TBI selectively induces a robust stimulation of the neurotoxic branch of the KP pathway. QUIN’s detrimental roles are supported by its association to adverse outcome potentially becoming an early prognostic factor post-TBI.

Recovery over 6 months of medical decision-making capacity after traumatic brain injury

OBJECTIVE

To investigate recovery of medical decision-making capacity (MDC) over 6 months in persons with traumatic brain injury (TBI) stratified by injury severity.

DESIGN

Longitudinal study comparing controls and patients with TBI 1 month after injury (t1) and 6 months after injury (t2).

SETTING

Inpatient TBI rehabilitation unit and outpatient neurology department.

PARTICIPANTS

Participants (N=151) consisted of control subjects (n=60) and patients with TBI (n=91) stratified by injury severity: mild TBI (mTBI; n=27), complicated mild TBI (cmTBI; n=20), and moderate/severe TBI (msevTBI; n=44).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We used the Capacity to Consent to Treatment Instrument to evaluate MDC performance on 5 consent standards (expressing choice, reasonable choice, appreciation, reasoning, and understanding). We also assigned capacity impairment ratings on the consent standards to each participant with TBI using cut scores referenced to control performance.

RESULTS

Control performance was stable across time on the consent standards. Patients with mTBI and cmTBI performed below controls on the understanding standard at t1 but not t2. Patients with msevTBI performed below controls on appreciation, reasoning, and understanding at t1, and on appreciation and understanding at t2, but showed substantial improvement over time.

CONCLUSIONS

Regardless of injury severity, all groups with TBI demonstrated baseline impairment of MDC with subsequent partial or full recovery of MDC over a 6-month period. However, a sizeable proportion of individual patients with TBI in each group continued to demonstrate capacity compromise at 6 months postinjury. Clinically, this finding suggests that individuals with TBI, regardless of injury severity, need continued monitoring regarding MDC for at least 6 months after injury.

Diffuse traumatic brain injury and the sensory brain

In this review we discuss the consequences to the brain's cortex, specifically to the sensory cortex, of traumatic brain injury. The thesis underlying this approach is that long-term deficits in cognition seen after brain damage in humans are likely underpinned by an impaired cortical processing of the sensory information needed to drive cognition or to be used by cognitive processes to produce a response. We take it here that the impairment to sensory processing does not arise from damage to peripheral sensory systems, but from disordered brain processing of sensory input.

Treatment consent capacity in patients with traumatic brain injury across a range of injury severity

OBJECTIVE

To investigate medical decision-making capacity (MDC) in patients with acute traumatic brain injury (TBI) across a range of injury severity.

METHODS

We evaluated MDC cross-sectionally 1 month after injury in 40 healthy controls and 86 patients with TBI stratified by injury severity (28 mild [mTBI], 15 complicated mild [cmTBI], 43 moderate/severe [msevTBI]). We compared group performance on the Capacity to Consent to Treatment Instrument and its 5 consent standards (expressing choice, reasonable choice, appreciation, reasoning, understanding). Capacity impairment ratings (no impairment, mild/moderate impairment, severe impairment) on the consent standards were also assigned to each participant with TBI using cut scores referenced to control performance.

RESULTS

One month after injury, the mTBI group performed equivalently to controls on all consent standards. In contrast, the cmTBI group was impaired relative to controls on the understanding standard. No differences emerged between the mTBI and cmTBI groups. The msevTBI group was impaired on almost all standards relative to both control and mTBI groups, and on the understanding standard relative to the cmTBI group. Capacity compromise (mild/moderate or severe impairment ratings) on the 3 clinically complex standards (understanding, reasoning, appreciation) occurred in 10%-30% of patients with mTBI, 50% of patients with cmTBI, and 50%-80% of patients with msevTBI.

CONCLUSIONS

One month following injury, MDC is largely intact in patients with mTBI, but is impaired in patients with cmTBI and msevTBI. Impaired MDC is prevalent in acute TBI and is strongly related to injury severity.

Relationship between, sleep spindles and clinical recovery in patients with traumatic brain injury: a simultaneous EEG and MEG study

Few methods can predict the prognosis and outcome of traumatic brain injury. Electroencephalographic (EEG) examinations have prognostic significance in the acute stage of posttraumatic coma, and some EEG variables have been correlated with outcome. Furthermore, spindle activity and reactivity in the acute stage have been associated with good recovery. Assessments of consciousness based on EEG and magnetoencephalographic (MEG) recordings provide valuable information for evaluating residual function, forming differential diagnoses and estimating prognosis. This study objectively investigated how fast spindles could relate to the recovery of consciousness and cognitive function during the post-acute to chronic stages of diffuse axonal injuries (DAIs). Sleep stage 2 was examined in 7 healthy participants and 8 patients with DAIs. Simultaneous EEG and MEG recordings were performed in the post-acute (mean 80 days) and chronic (mean 151 days) stages of recovery. Magnetoencephalography enabled equivalent current dipole estimates of fast spindle sources. Clinical recovery was evaluated by consciousness, neuropsychological examination, and outcome. Six severe and two moderate injuries were studied in patients with favorable 1-year outcomes. In the sub-acute stage, significant decreases were detected in the frequency, amplitude, and cortical activation source strengths of spindle activities, but these recovered during the chronic stage. In the chronic stage, the Wechsler adult intelligence factor scale and subset patterning revealed significant improvement in cognitive function. These results suggested that spindles may reflect recovery of consciousness and cognitive function following a DAI.

Concussions in soccer: a current understanding

OBJECTIVE

Traumatic brain injury (TBI) is a significant public health problem in the United States, with approximately 1.5-2 million TBIs occurring each year. However, it is believed that these figures underestimate the true toll of TBI. Soccer is the most popular sport in the world and has a following of millions in the United States. Soccer is a sport not traditionally identified as high-risk for concussions, yet several studies have shown that concussion rates in soccer are comparable to, and often exceed those of, other contact sports. As many as 22% of all soccer injuries are concussions.

METHODS

Soccer is a sport not traditionally identified as high risk for concussions, yet several studies have shown that concussion rates in soccer are comparable to, and often exceed those of, other contact sports. As many as 22% of all soccer injuries are concussions. Head injury during soccer is usually the result of either "direct contact" or contact with the ball while "heading" the ball. Relationships between the number of headers sustained in a single season and the degree of cognitive impairment (attention and visual/verbal memory) have been demonstrated. It is also likely that multiple concussions may cause cumulative neuropsychologic impairment in soccer players.

RESULTS

Although our understanding of risk factors for sports-related concussions is far from complete, there is great potential for prevention in sports-related concussions. Several measures must be taken to avert the development of concussions in soccer and, when they take place, reduce their effects. These include the development and testing of effective equipment during play, the maintenance of regulatory standards for all such equipment, educating young athletes on the safe and appropriate techniques used during play, and strict adherence to the rules of competition.

CONCLUSIONS

In spite of such preventive measures, concussions in soccer will continue to occur. Considering the frequency of concussions in soccer, the serious sequelae of these concussions, and because almost half of concussed soccer players were noncompliant with recommended American Academy of Neurology return-to-play guidelines, further measures must be taken to protect players, in addition to understanding those criteria that result in removing an injured player from competition and the steps by which to safely return an athlete to competition after injury.

Post-traumatic hypoxia exacerbates neurological deficit, neuroinflammation and cerebral metabolism in rats with diffuse traumatic brain injury

Background

The combination of diffuse brain injury with a hypoxic insult is associated with poor outcomes in patients with traumatic brain injury. In this study, we investigated the impact of post-traumatic hypoxia in amplifying secondary brain damage using a rat model of diffuse traumatic axonal injury (TAI). Rats were examined for behavioral and sensorimotor deficits, increased brain production of inflammatory cytokines, formation of cerebral edema, changes in brain metabolism and enlargement of the lateral ventricles.

Methods

Adult male Sprague-Dawley rats were subjected to diffuse TAI using the Marmarou impact-acceleration model. Subsequently, rats underwent a 30-minute period of hypoxic (12% O₂/88% N₂) or normoxic (22% O₂/78% N₂) ventilation. Hypoxia-only and sham surgery groups (without TAI) received 30 minutes of hypoxic or normoxic ventilation, respectively. The parameters examined included: 1) behavioural and sensorimotor deficit using the Rotarod, beam walk and adhesive tape removal tests, and voluntary open field exploration behavior; 2) formation of cerebral edema by the wet-dry tissue weight ratio method; 3) enlargement of the lateral ventricles; 4) production of inflammatory cytokines; and 5) real-time brain metabolite changes as assessed by microdialysis technique.

Results

TAI rats showed significant deficits in sensorimotor function, and developed substantial edema and ventricular enlargement when compared to shams. The additional hypoxic insult significantly exacerbated behavioural deficits and the cortical production of the pro-inflammatory cytokines IL-6, IL-1β and TNF but did not further enhance edema. TAI and particularly TAI+Hx rats experienced a substantial metabolic depression with respect to glucose, lactate, and glutamate levels.

Conclusion

Altogether, aggravated behavioural deficits observed in rats with diffuse TAI combined with hypoxia may be induced by enhanced neuroinflammation, and a prolonged period of metabolic dysfunction.

Understanding the ‘miserable minority’: a diasthesis-stress paradigm for post-concussional syndrome

Opinions about persisting post-concussional symptoms after minor traumatic brain injury still reflect a polarization of views around the sterile debate concerning the psychological vs organic origins of symptoms. Reviews of the experimental literature do not always integrate the often diverse perspectives that explain persisting symptoms of concussion. As a result, the disorder is still poorly understood. In this review, a diasthesis-stress paradigm examines the interaction between physiological and psychological factors that generate and maintain post-concussional symptoms. Motivational factors and different coping strategies are considered to explain why some people are at risk of developing a post-concussional syndrome. The early iatrogenic potential of GPs and hospital doctors who may create insecurity or reinforce illness perceptions is considered. Finally, the rationale and effectiveness of interventions that ameliorate the impact of early post-concussional symptoms is reviewed to see if prevention of the post-concussional syndrome is more effective than cure.

Epidemiology of acquired brain injury (ABI) in adults: prevalence of long-term disabilities and the resulting needs for ongoing care in the region of Flanders, Belgium

In order to plan services for long-term care of those with acquired brain injury (ABI), the prevalence of ABI was investigated by using a postal inquiry sent to a representative sample of general practitioners, of whom 121 cooperated and registered 186 cases. The corresponding estimated prevalence of adults with ABI-related disabilities is 183 per 100 000 population. The large majority remained at home without professional assistance. One in five had resumed education or regained full employment, but over half spent their day at home with no specific activity. The need for specific care at home was present in almost half of the patients. One-quarter had employment-related needs, and one in five had living needs for specialized accommodation or supported living. In conclusion, this study primarily revealed unfulfilled needs in the area of day services aiming at a maximal social and professional reintegration.

Concussive symptoms in emergency department patients diagnosed with minor head injury

BACKGROUND

Evidence-based protocols exist for Emergency Department (ED) patients diagnosed with minor head injury. These protocols focus on the need for acute intervention or in-hospital management. The frequency and nature of concussive symptoms experienced by patients discharged from the ED are not well understood.

OBJECTIVES

To examine the prevalence and nature of concussive symptoms, up to 1 month post-presentation, among ED patients diagnosed with minor head injury.

METHODS

Eligible and consenting patients presenting to Kingston EDs with minor head injury (n = 94) were recruited for study. The Rivermead Post-Concussion Symptoms Questionnaire was administered at baseline and at 1 month post-injury to assess concussive symptoms. This analysis focused upon acute and ongoing symptoms.

RESULTS

Proportions of patients reporting concussive symptoms were 68/94 (72%) at baseline and 59/94 (63%) at follow-up. Seventeen percent of patients (18/102) were investigated with computed tomography scanning during their ED encounter. The prevalence of somatic symptoms declined between baseline and follow-up, whereas some cognitive and emotional symptoms persisted.

CONCLUSION

The majority of patients who present to the ED with minor head injuries suffer from concussive symptoms that do not resolve quickly. This information should be incorporated into discharge planning for these patients.

Voxel-based statistical analysis of cerebral blood flow using Tc-99m ECD brain SPECT in patients with traumatic brain injury: group and individual analyses

PURPOSE

Statistical parametric mapping (SPM) was applied to brain perfusion single photon emission computed tomography (SPECT) images in patients with traumatic brain injury (TBI) to investigate regional cerebral abnormalities compared to age-matched normal controls.

METHOD

Thirteen patients with TBI underwent brain perfusion SPECT were included in this study (10 males, three females, mean age 39.8 +/- 18.2, range 21 - 74). SPM2 software implemented in MATLAB 5.3 was used for spatial pre-processing and analysis and to determine the quantitative differences between TBI patients and age-matched normal controls.

RESULTS

Three large voxel clusters of significantly decreased cerebral blood perfusion were found in patients with TBI. The largest clusters were area including medial frontal gyrus (voxel number 3642, peak Z-value = 4.31, 4.27, p = 0.000) in both hemispheres. The second largest clusters were areas including cingulated gyrus and anterior cingulate gyrus of left hemisphere (voxel number 381, peak Z-value = 3.67, 3.62, p = 0.000). Other clusters were parahippocampal gyrus (voxel number 173, peak Z-value = 3.40, p = 0.000) and hippocampus (voxel number 173, peak Z-value = 3.23, p = 0.001) in the left hemisphere. The false discovery rate (FDR) was less than 0.04.

CONCLUSION

From this study, group and individual analyses of SPM2 could clearly identify the perfusion abnormalities of brain SPECT in patients with TBI. Group analysis of SPM2 showed hypoperfusion pattern in the areas including medial frontal gyrus of both hemispheres, cingulate gyrus, anterior cingulate gyrus, parahippocampal gyrus and hippocampus in the left hemisphere compared to age-matched normal controls. Also, left parahippocampal gyrus and left hippocampus were additional hypoperfusion areas. However, these findings deserve further investigation on a larger number of patients to be performed to allow a better validation of objective SPM analysis in patients with TBI.

DELAYED ELEVATION OF SOLUBLE TUMOR NECROSIS FACTOR RECEPTORS P75 AND P55 IN CEREBROSPINAL FLUID AND PLASMA AFTER TRAUMATIC BRAIN INJURY

Recent studies have reported a significant inflammatory reaction in the brain and the systemic circulation after traumatic brain injury (TBI). Although there is growing knowledge and understanding of the mechanisms and mediators involved in the proinflammatory reaction, little is known about the anti-inflammatory mediators in the brain. As tumor necrosis factor alpha (TNF-alpha) plays a detrimental role in the initiation and promotion of the proinflammatory reactions after TBI, the endogenous scavenger system, represented by the soluble TNF receptors (sTNFRs) p55 and p75, seems to have an important anti-inflammatory capacity by binding to circulating TNF-alpha. To evaluate this potentially anti-inflammatory response to trauma, we analyzed sTNFR p55 and p75 in paired plasma/cerebrospinal fluid (CSF) samples of 29 patients who encountered TBI. Values were compared with reference values obtained from healthy volunteers (n = 91). Patients with TBI showed significantly (P < 0.001) elevated sTNFR p55 and p75 values starting from day 2 and lasting until day 10 if compared with reference values. In contrast to the early increased plasma values p55 and p75 showed slowly increasing CSF values starting on day 4 and 3, respectively. Significantly (P < 0.001) increased CSF values of p 55 were determined on days 4 to 6 and day 9. p75 showed significantly (P < 0.001) elevated values if compared with control values on days 7 and 9. The sTNFR p55 and p75 show a distinct and long-lasting elevation in plasma of patients after TBI. In contrast, CSF values display a delayed and less intense elevation of both receptors in patients with TBI. These findings are suggestive of an imbalance of the proinflammatory and anti-inflammatory reactions of the central nervous system after trauma, with an emphasis on the proinflammatory mechanisms and a slow increase of potentially anti-inflammatory mediators such as the soluble TNFRs after TBI.

Downregulation of glial scarring after brain injury: the effect of purine nucleoside analogue ribavirin

The weak regenerative capacity of self-repair after injury to the adult brain is caused by the formation of glial scar due to reactive astrogliosis. In the present study the beginning of reactive astrogliosis in the adult, as shown immunocytochemically by upregulation of glial fibrillary acidic protein (GFAP) and vimentin, was seen two days after the left sensorimotor cortex lesion, being maximal during the first two weeks and declining by 30 days after the lesion. This was accompanied by intensive glial scarring. Conversely, after the neonatal lesion a lack of gliotic scar was seen until 30 days postsurgery, although the pattern of GFAP and vimentin expression during recovery period was the same. The aim of the study was to define an appropriate therapeutic intervention that could modulate astrocyte proliferation and diminish glial scar formation after adult brain lesion. For this purpose the effects of an antiproliferative agent, the purine nucleoside analogue ribavirin was examined. It was shown that daily injection of ribavirin for 5 and 10 days considerably decreased the number of reactive astrocytes, while slight GFAP labeling was restricted to the lesion site. Obtained results show that ribavirin treatment downregulates the process of reactive astrogliosis after adult brain injury, and thus may be a useful approach for improving neurological recovery from brain damage.

Diffusion-Weighted Imaging of Edema following Traumatic Brain Injury in Rats: Effects of Secondary Hypoxia

Hypoxia and edema are frequent and serious complications of traumatic brain injury (TBI). Therefore, we examined the effects of hypoxia on edema formation after moderate lateral fluid percussion (LFP) injury using NMR diffusion-weighted imaging (DWI). Adult Sprague-Dawley rats were separated into four groups: sham uninjured (S), hypoxia alone (H), trauma alone (T), and trauma and hypoxia (TH). Animals in Groups T and TH received LFP brain injury, with Groups H and TH undergoing 30 min of moderately severe hypoxia (FiO2 = 0.11) immediately after surgery or TBI (respectively). DWIs were obtained at 2, 4, and 24 h and at 1 week post injury, and apparent diffusion coefficient (ADC) maps were constructed. Animals in Groups T and TH showed an early decrease (p < 0.001) in ADC values in the cortex ipsilateral to TBI 4 hr post injury, followed by elevated ADCs 1 week later (p < 0.05). No significant differences in ADC values were seen between T and TH groups in the ipsilateral cortex. In contrast, the ipsilateral hippocampus for Group TH showed only increasing ADC values. This hyperintensity in the ADC map began at 2 h after TBI, was significant by 24 h (p < 0.05), and reached a maximum at 1 week. This hyperintensity was not observed in Group T. Histopathology seen in TBI animals corresponded well with the pathology observed with MRI. Midline shifts reflecting edema were only observed in TBI animals with little difference between normoxic (T) and hypoxic animals (TH). In sum, this study demonstrates that the development and extent of brain edema following TBI can be examined in vivo in rats using DWI technology. TBI resulted in an early decrease in ADC values indicating cytotoxic edema in the cortex that was followed at 1 week by an increase in the ADC that was associated with decreased tissue cellularity. Histopathology corresponded well to the regions of brain injury and edema visualized by T2 and DWI procedures. Overall, the addition of hypoxia to brain injury resulted in a small increase in the magnitude of edema in hippocampus and cortex over that seen with trauma alone.

Surgical treatment of late-onset post-traumatic partial seizures in a child

INTRODUCTION

Although post-traumatic epilepsy accounts for a small number of epileptic patients, it should not be underestimated since it primarily affects children and young adults and can result in psychosocial disability and death.

CASE REPORT

We present the case of a 14-year-old girl referred to us because of refractory partial seizures. The patient had experienced a head trauma at the age of 6 months requiring surgical treatment due to a large right fronto-temporo-parietal extradural hematoma. She was discharged on phenytoin prophylactically. At the age of 4 she had her first partial seizure, characterized by left arm and leg tonic-clonic movements. Her physical examination revealed a subtle left brachiocrural hemiparesis and developmental delay. Several antiepileptic drugs were tried and seizure control was not achieved. They were occurring 8-10 times per day. The proposed surgical treatment was based on the consistent seizure semiology and on the affected area as identified by MRI and visible macroscopically to the neurosurgeon. At 9 years follow-up the patient is seizure free. Her motor skills are adequate for living a normal life.

CONCLUSION

We emphasize that selected patients may benefit from surgical treatment when epilepsy results from a trauma.

Multi-modal monitoring of acute brain injury

OBJECTIVE

To review the scientific basis for and utility of the traditional cerebral monitors used currently in neurointensive care, together with research techniques that are soon likely to become used in managing severe head injury and subarachnoid haemorrhage.

DESIGN AND CONTENT

Firstly, the pathophysiology of acute brain injury including cerebral haemodynamics, oxygen and metabolism and the role of secondary insults are discussed. Secondly, the importance of assessment of cerebrovascular autoregulation and reactivity is reviewed together with methods for its continuous non-invasive measurement using transcranial Doppler and intracranial pressure/arterial pressure recordings. Thirdly, the respective roles of jugular venous oxygen and brain tissue oxygen monitoring are analysed. Fourthly, the use of cerebral microdialysis is described, together with an overview of its utility.

CONCLUSION

Cerebral multimodal monitoring can be helpful for the optimal management of acute brain injury and essential for future exploratory trials of neuroprotective drugs.

Immediate neurocognitive effects of concussion

OBJECTIVE

To prospectively measure the immediate neurocognitive effects and early course of recovery from concussion and to examine the effects of loss of consciousness (LOC) and posttraumatic amnesia (PTA) on the severity of neurocognitive impairment immediately after concussion.

METHODS

A sports-related concussion research model was used to allow prospective immediate evaluation of concussion. A total of 2385 high school and college football players were studied. Ninety-one players (3.8%) sustained concussions during the study. A brief neurocognitive and neurological screening measure, the Standardized Assessment of Concussion, was used to assess cognitive functioning before the football season, immediately after injury, and 15 minutes, 48 hours, and 90 days after injury.

RESULTS

Standardized Assessment of Concussion scores immediately after concussion were significantly lower than the preseason baseline score and the noninjured population baseline mean, even for injured subjects without LOC or PTA. Subjects with LOC were most severely impaired immediately after injury, whereas those without LOC or PTA were least impaired. Significant impairment was also detected 15 minutes after injury, but all three groups returned to baseline levels of cognitive functioning within 48 hours.

CONCLUSION

These findings are the first to demonstrate not only that a gradient of increasing concussion severity is represented by PTA and LOC but also that measurable neurocognitive abnormalities are evident immediately after injury without PTA or LOC.

Posttraumatic hypothermia is neuroprotective in a model of traumatic brain injury complicated by a secondary hypoxic insult

OBJECTIVE

Human traumatic brain injury frequently results in secondary complications, including hypoxia. In previous studies, we have reported that posttraumatic hypothermia is neuroprotective and that secondary hypoxia exacerbates histopathologic outcome after fluid-percussion brain injury. The purpose of this study was to assess the therapeutic effects of mild (33 degrees C) hypothermia after fluid-percussion injury combined with secondary hypoxia. In addition, the importance of the rewarming period on histopathologic outcome was investigated.

DESIGN

Prospective experimental study in rats.

SETTING

Experimental laboratory in a university teaching hospital.

INTERVENTION

Intubated, anesthetized rats underwent normothermic parasagittal fluid-percussion brain injury (1.8-2.1 atmospheres) followed by either 30 mins of normoxia (n = 6) or hypoxic (n = 6) gas levels and by 4 hrs of normothermia (37 degrees C). In hypothermic rats, brain temperature was reduced immediately after the 30-min hypoxic insult and maintained for 4 hrs. After hypothermia, brain temperature was either rapidly (n = 6) or slowly (n = 5) increased to normothermic levels. Rats were killed 3 days after traumatic brain injury, and contusion volumes were quantitatively assessed.

MEASUREMENTS AND MAIN RESULTS

As previously shown, posttraumatic hypoxia significantly increased contusion volume compared with traumatic brain injury-normoxic animals (p <.02). Importantly, although posttraumatic hypothermia followed by rapid rewarming (15 mins) failed to decrease contusion volume, those animals undergoing a slow rewarming period (120 mins) demonstrated significantly (p <.03) reduced contusion volumes, compared with hypoxic normothermic rats.

CONCLUSIONS

These data emphasize the beneficial effects of posttraumatic hypothermia in a traumatic brain injury model complicated by secondary hypoxia and stress the importance of the rewarming period in this therapeutic intervention.

Bedside monitoring of cerebral blood flow by transcranial thermo-dye-dilution technique in patients suffering from severe traumatic brain injury or subarachnoid hemorrhage

Bedside measurement of cerebral blood flow (CBF) represents an important feature in monitoring of neurointensive care patients which is hard to establish. Therefore, we adopted a recently described thermo-dye-dilution-based approach for monitoring CBF in patients suffering from severe cerebral insults, that is, traumatic brain injury (TBI) or subarachnoid hemorrhage (SAH). Combined fiberoptic-thermistor catheters were placed in one jugular venous bulb and in the abdominal aorta of 16 patients. Following central venous injection of a 50-mL bolus of precooled indocyanine green (ICG) solution, CBF was determined as a function of the mean transit times of coldness and dye. In addition, measurements of CBF using stable xenon-enhanced computerized tomography (sXe-CT) were simultaneously performed in 10 patients. A total of 272 thermo-dye-dilution measurements yielded 196 valid results, with CBF ranging from 26.2 to 144.8 mL 100 g(-1) min(-1). Reproducibility was fairly good, with the standard deviation within sets of repeated measurements being 6.3 mL 100 g(-1) min(-1) and 9.4 as the mean coefficient of variation. Simultaneously obtained values with sXe-CT displayed a good correlation (r = 0.843, p < 0.01); however, the thermo-dye-dilution method consistently overestimated CBF. Data analysis using the Bland and Altman methodology revealed a large bias of 45.7 mL 100 g(-1) min(-1) with a +/- 2 SD range of 37 mL 100 g(-1) min(-1), indicating a rather poor agreement. The thermo-dye-dilution method proved a reasonably reproducible technique, enabling repeated long-term bedside measurements of CBF in neurointensive care patients with a minimum of time effort. However, a high failure rate was also noted, and consistent overestimation of perfusion was observed in comparison to sXe-CT measurements. Although the thermo-dye-dilution technique has been successfully validated in patients with normal neurovascular function, its applicability for bedside monitoring of CBF appears uncertain in patients suffering from severe TBI or SAH.

Technetium-99m ECD single photon emission computed tomography in brain trauma: comparison of early scintigraphic findings with long-term neuropsychological outcome

OBJECTIVE

The aim of this study was to assess the prognostic value of early brain scintigraphy in head injury in relation to long-term neuropsychological behavior. Twenty-four patients underwent technetium-99m (Tc-99m) ethyl cysteinate dimer single photon emission computed tomography (SPECT) within 1 month of the trauma. Scintigraphic abnormalities were evaluated both visually and semiquantitatively using the brain-to-cerebellum ratio method. The clinical neuropsychological investigation was conducted to evaluate abnormalities related to motor deficit, frontal behavior, and memory and language disorders. All patients had abnormalities on SPECT scan. One year after trauma, 14 patients (58%) had neuropsychological sequelae. The brain-to-cerebellum ratios in the left basal ganglia and brain stem were significantly decreased in patients with memory disorders (P = .03 and P = .02, respectively). Moreover, SPECT visual analysis indicated that low uptake in the basal ganglia, thalamus, and brain stem was associated with subsequent motor deficit, frontal behavior, and language and memory disorders. The authors conclude that brain SPECT can be valuable in predicting the neuropsychological behavior of survivors of severe head injury.

Altered cellular metabolism following traumatic brain injury: a magnetic resonance spectroscopy study

Experimental studies have reported early reductions in pH, phosphocreatine, and free intracellular magnesium following traumatic brain injury using phosphorus magnetic resonance spectroscopy. Paradoxically, in clinical studies there is some evidence for an increase in the pH in the subacute stage following traumatic brain injury. We therefore performed phosphorus magnetic resonance spectroscopy on seven patients in the subacute stage (mean 9 days postinjury) following traumatic brain injury to assess cellular metabolism. In areas of normal-appearing white matter, the pH was significantly alkaline (patients 7.09 +/- 0.04 [mean +/- SD], controls 7.01 +/- 0.04, p = 0.008), the phosphocreatine to inorganic phosphate ratio (PCr/Pi) was significantly increased (patients 4.03 +/- 1.18, controls 2.64 +/- 0.71, p = 0.03), the inorganic phosphate to adenosine triphosphate ratio (Pi/ATP) was significantly reduced (patients 0.37 +/- 0.10, controls 0.56 +/- 0.19, p = 0.04), and the PCr/ATP ratio was nonsignificantly increased (patients 1.53 +/- 0.29, controls 1.34 +/- 0.19, p = 0.14) in patients compared to controls. Furthermore, the calculated free intracellular magnesium was significantly increased in the patients compared to the controls (patients 0.33 +/- 0.09 mM, controls 0.22 +/- 0.09 mM, p = 0.03)). Proton spectra, acquired from similar regions showed a significant reduction in N-acetylaspartate (patients 9.64 +/- 2.49 units, controls 12.84 +/- 2.35 units, p = 0.03) and a significant increase in choline compounds (patients 7.96 +/- 1.02, controls 6.67 +/- 1.01 units, p = 0.03). No lactate was visible in any patient or control spectrum. The alterations in metabolism observed in these patients could not be explained by ongoing ischemia but might be secondary to a loss of normal cellular homeostasis or a relative alteration in the cellular population, in particular an increase in the glial cell density, in these regions.

A randomized trial of two treatments for mild traumatic brain injury: 1 year follow-up

The purpose of this study was to provide 1 year follow-up data to a previous paper that compared single-session (SS) treatment to treatment-as-needed (TAN) outcomes for mild traumatic brain injury (MTBI) survivors at 3 months post-injury. Participants were 105 adults with MTBI who were recruited from consecutive admissions to two hospital emergency wards, and randomly assigned to either the SS or TAN modality. No group differences in outcome were evident at 12 months post-injury. As well, improvements seen in the groups after 3 months were maintained at 12 months. As improvements between 3 and 12 months were negligible, self-reported improvement after a treated MTBI typically occurred within the first 3 months. Brief educational intervention given soon after MTBI appears to be as helpful as more intensive treatment for most MTBI survivors for at least 12 months post-injury.

Snapshot view of emergency neurosurgical head injury care in Great Britain and Ireland

OBJECTIVES

To study the availability of neurosurgical intensive care for the traumatically brain injured in all 36 neurosurgical centres in the United Kingdom and Ireland receiving head injuries, the response times to referral, and the advice given to the referring hospitals.

METHODS

Telephone survey of receiving neurosurgeons regarding their bed status and their advice on three hypothetical case scenarios. Outcome measures included response times for an acute head injury to be accepted to a neurosurgical centre; the intensive care bed status; variations in advice given to the referring hospitals with regard to ventilation, use of mannitol, steroids, anticonvulsants, and antibiotics.

RESULTS

There were 43 neurosurgical intensive care beds available for an overall estimated population of 63.6 million. There were 1.8 beds available/million of the population for non-ventilated patients, 0.64 beds available/million for ventilated patients, and 0.55 beds available/million for ventilated paediatric patients. London had a shortage of beds with 0.19 adult beds for ventilation/million north of the Thames and 0.14 adult beds for ventilation/million south of the Thames. The median response time for a patient with an extradural haematoma to be accepted for transfer was 6 minutes and 89% of such a referral was accepted within 30 minutes. Clinically significant delays in receiving referrals (over 30 minutes) occurred in four units. Practices regarding the use of hyperventilation, mannitol, anticonvulsants, and antibiotics showed little conformity and in some cases were against the available evidence and advice given by published guidelines.

CONCLUSIONS

There is a severe shortage of available emergency neurosurgical beds especially in the south east of England. The lack of immediately available neurosurgical intensive care beds results in delays of transfer that could adversely affect the outcome of surgery for traumatic intracranial haematoma. Advice given to the referring units by the receiving doctors is very variable.

Secondary hypoxia following moderate fluid percussion brain injury in rats exacerbates sensorimotor and cognitive deficits

Human head trauma is frequently associated with respiratory problems resulting in secondary hypoxic insult. To document the behavioral consequences of secondary hypoxia in an established model of traumatic brain injury (TBI), intubated anesthetized animals were subjected to fluid percussion (FP) injury (1.87-2.17 atm) followed by 30 min of either normoxic (TBI-NO, n = 10) or hypoxic (TBI-HY, n = 11; pO2 = 30-40 mm Hg) gas levels. Sham animals (n = 19) underwent all manipulations except for the actual trauma. Animals were tested on various sensorimotor tasks beginning 3 days after FP injury along with cognitive testing on days 22 through 29 posttrauma. The secondary hypoxic insult exacerbated the sensorimotor deficits on beam-walking compared to those animals only receiving trauma. Cognitive impairments were also observed in the TBI-HY group in the hidden platform task compared to FP injury alone. These data indicate that a secondary hypoxic insult exacerbates both sensorimotor and cognitive deficits after TBI. This study provides direct evidence that incidences of hypoxia after brain trauma may potentially result in an increase in neurological deficits for the subpopulation of head injured patients undergoing hypoxic conditions further warranting strict monitoring of these events.

Closed head injury in the rat induces whole body oxidative stress: overall reducing antioxidant profile

Traumatic injury to the brain triggers the accumulation of harmful mediators, including highly toxic reactive oxygen species (ROS). Endogenous defense mechanism against ROS is provided by low molecular weight antioxidants (LMWA), reflected in the reducing power of the tissue, which can be measured by cyclic voltammetry (CV). CV records biological peak potential (type of scavenger), and anodic current intensity (scavenger concentration). The effect of closed head injury (CHI) on the reducing power of various organs was studied. Water and lipid soluble extracts were prepared from the brain, heart, lung, kidney, intestine, skin, and liver of control and traumatized rats (1 and 24 h after injury) and total LMWA was determined. Ascorbic acid, uric acid, alpha-tocopherol, carotene and ubiquinol-10 were also identified by HPLC. The dynamic changes in LMWA levels indicate that the whole body responds to CHI. For example, transient reduction in LMWA (p<0.01) in the heart, kidney, lung and liver at 1 h suggests their consumption, probably due to interaction with locally produced ROS. However, in some tissues (e.g., skin) there was an increase (p<0.01), arguing for recruitment of higher than normal levels of LMWA to neutralize the ROS. alpha-Tocopherol levels in the brain, liver, lung, skin, and kidney were significantly reduced (p<0.01) even up to 24 h. We conclude that although the injury was delivered over the left cerebral hemisphere, the whole body appeared to be under oxidative stress, within 24 h after brain injury.

Minor head trauma in anticoagulated patients

OBJECTIVE

To determine the incidence of clinically significant intracranial injury in the anticoagulated patient suffering minor head trauma without loss of consciousness (LOC) or acute neurologic abnormality.

METHODS

A retrospective chart review was performed based on a computerized search of electronic patient records from six community hospital EDs, one of which is a trauma center. Patients taking warfarin who sustained minor head trauma without LOC having no acute neurologic abnormalities treated from January 1994 to January 1996 were identified using a search of electronic ED records. Charts were reviewed for mechanism of injury, physical examination findings of head injury, and concomitant injury. Prothrombin time and head CT results were recorded if obtained. For those patients not receiving a head CT on ED evaluation, telephone follow-up was performed to determine outcome.

RESULTS

There were 65 patients meeting inclusion criteria. Thirty-eight patients had prothrombin times obtained, with ranges from 12.0 sec to 30.7 sec. There was no intracranial injury found in any of the 39 patients having a head CT. Additionally, follow-up on the 26 patients who did not undergo CT scanning revealed no evidence of complications related to their head injuries.

CONCLUSIONS

The incidence of clinically significant intracranial injury is extremely low in the anticoagulated patient suffering minor blunt head trauma without LOC or acute neurologic abnormality. CT scanning may not be necessary in these patients. Larger prospective studies are needed to confirm these findings.

Use of vasopressors to raise cerebral perfusion pressure in head injured patients

Cerebral ischemia due to low cerebral perfusion pressure (CPP) is the most important secondary effect of severe head injury. There is consensus regarding the maintenance of this pressure at levels above 70 mm Hg. One way to elevate CPP is by increasing mean arterial pressure (MAP). In this study, the authors attain this target by using adrenergic vasopressors investigating the effectiveness of dopamine, noradrenaline and methoxamine in 16 severe head injured patients. The results were: a) the increase of MAP effectively increased CPP without changes in intracranial pressure (ICP) and cerebral extraction of oxygen (CEO2); b) noradrenaline at a dose of 0.5 mg to 5 mg/h was effective and safe and might be considered the drug of choice; c) dopamine was not as effective at a high dose of 10 to 42.5 micrograms/kg/min; d) methoxamine given as a bolus was an effective way to control sudden decreases in MAP. It made the patients more responsive to dopamine. No important undesirable reactions occurred during the study.

[Treatment of intracranial hypertension in the case of severe craniocerebral injuries]

More than 50% of severely head-injured patients develop increased intracranial pressure, risking exacerbating ischaemic insults to the already injured brain. In approximately 10% of these cases, intracranial pressure may become unresponsive to medical or surgical treatment, with a resulting mortality of over 90%. The main emphasis should be on full intensive care, based on the prophylaxis of the devastating effects of secondary insults to the injured brain. Specific treatment should be directed towards controlling intracranial pressure and maintaining a cerebral perfusion pressure over 70 mmHg, while avoiding, where feasible, treatment modalities at risk of exacerbating cerebral ischaemia. Recently, an algorithm for treating intracranial hypertension under three different therapeutic situations has been suggested, based on the successive application of effective agents with increasing associated risks. Therapeutic modalities of this protocol are discussed.

[Use of Glasgow coma scale by anesthesia and intensive care internists in brain injured patients]

OBJECTIVE

To evaluate the quality and reliability of the Glasgow coma scale (GCS) score when determined, in head trauma patients, by trainees in anaesthesiology.

STUDY DESIGN

Prospective survey. USERS: One hundred trainees in their first to fourth year of training in anaesthesiology.

METHODOLOGY

A questionnaire completed by the trainees concerning: demographic data; place, time and qualification of the physician determining the first GCS score; time and qualification of the physician determining the subsequent GCS score; assessment of the GCS score in case of asymmetrical motor response, tracheal intubation, bilateral eyelid oedema, or circulatory or ventilatory failure.

RESULTS

Sixty questionnaires were available for analysis. Lack of compliance with the rules for the GCS score evaluation resulted in many errors by most of the trainees. Only a few of them determined an accurate GCS score in cases of asymmetric motor response or impossibility to determine verbal or ocular response. Finally, GCS scores were determined later only very rarely.

CONCLUSION

In order to provide optimal care and allow an accurate assessment of therapeutic efficiency, special attention should be given to the teaching of the GCS scoring method in head trauma patients.

Quantitative electroencephalographic evaluation of non-fatal and fatal traumatic coma

Diffuse axonal injury (DAI) is an important cause of morbidity and mortality after traumatic brain injury (TBI), and its severity is therefore a major determinant of outcome. There have been suggestions that the extent of DAI may be reflected in quantitative measures of cerebral function, including the electroencephalogram (EEG) and brain-stem auditory evoked potentials (BAEPs). It has therefore been proposed that these quantitative methods of analysis may provide objective predictors of outcome following TBI. We prospectively investigated the relationship between quantitative EEG and BAEP measures and outcome, in 60 comatose patients (47 male and 13 female; age range 1-80 years, mean 36.4) after severe, closed head injury (post-resuscitation Glasgow Coma Scale (GCS) of 8). The Spearman correlation coefficients (rs) have been calculated for quantitative EEG measures (mean regional power and interhemispheric coherence) and BAEPs with patient outcome on the Glasgow Outcome and Disability Rating Scales at 6 months and 1 year. The measures most significantly correlated with outcome (P < 0.001) are over the left hemisphere, beta activity power (amplitude squared) in the fronto-central and centro-temporal regions, and alpha activity power in the centro-temporal region. We found no correlation between interhemispheric coherence (a statistical measure of cross-correlation in the frequency domain) and outcome at either 6 months or 1 year post-injury. In 10 fatalities, we examined the relationship between interhemispheric EEG coherence prior to deaths and the histopathological severity of DAI, in concordant regions. The only significant correlation between DAI and interhemispheric coherence is seen in the alpha band at the temporo-occipital site (rs = -0.79, P = 0.007). Our data indicate that there is regional information in EEG power spectra over the left hemisphere, which could be used in prognostic predictions for patients in coma after severe TBI. We were unable to demonstrate a correlation between interhemispheric coherence and outcome, or any clear and consistent evidence of a relationship between interhemispheric coherence and the severity of DAI.

Evaluation of the transient hyperemic response test in head-injured patients

The transient hyperemic response test has been shown to provide an index of cerebral autoregulation in healthy individuals and in patients who have suffered a subarachnoid hemorrhage. In this study, the test was applied to patients who had received a severe head injury, and the value of the test was assessed by comparing its result with the individual's clinical condition (Glasgow Coma Scale [GCS] score), cerebral perfusion pressure (CPP), transcranial Doppler wave form-derived index for cerebral autoregulation (relationship between the CPP and the middle cerebral artery flow velocity), and outcome (Glasgow Outcome Scale [GOS] score). Forty-seven patients, aged 16 to 63 years, with head injuries were included in the study. Signals of intracranial pressure, arterial blood pressure, flow velocity, and cortical microcirculatory flux were digitized and recorded for a period of 30 minutes using special computer software. Two carotid compressions were performed at the beginning of each recording. The transient hyperemic response ratio (THRR: the ratio of the hyperemic flow velocity recorded after carotid release and the precompression baseline flow velocity) was calculated, as was the correlation coefficient Sx used to describe the relationship between slow fluctuations in the systolic flow velocity and CPP throughout the period of recording. No significant changes in CPP were found during compression. There was a significant correlation between the THRR and the Sx (r = 0.49, p < 0.0001). The hyperemic response proved to be lower in patients who exhibited a poor clinical grade at presentation (GCS scores < 6, p = 0.01) and lower in patients achieving a poor outcome (GOS scores of 3, 4, and 5, p = 0.003). Loss of postcompression hyperemia occurred when the CPP fell below 50 mm Hg. The carotid compression test provides a simple index of cerebral autoregulation that is relevant to the clinical condition and outcome of the severely head injured patient.

Severe head injury in the United Kingdom and Ireland: a survey of practice and implications for management

OBJECTIVE

To study the current intensive care management of patients with severe head injury (defined as a Glasgow Coma Scale score of < or = 8) in neurosurgical referral centers in the United Kingdom (UK) and ireland.

DATA COLLECTION

A questionnaire was sent to the directors of the 44 neurosurgical referral units identified from the UK Medical Directory. After 4 wks, a copy of the questionnaire was sent to all nonresponders, with a cover letter urging them to respond. The aim was to collect data regarding the characteristics of the intensive care units (ICU), sedation, monitoring modalities used, the treatment of intracranial hypertension, and general care of severely head-injured patients.

DATA EXTRACTION

Forty completed questionnaires were returned. Only 35 (88%) centers provided care for the severely head-injured as defined in the questionnaire. Patients were managed in specialized neurosurgical ICUs in 66% of centers and in general ICUs in the remainder of the centers. The ICUs were coordinated by an anesthesiologist in 66% of instances and by a neurosurgeon in 23%. The mean number of beds per units was 7.9 (range 4 to 16), with 1:1 nurse/bed ratio and 5.5 nurses per bed (total number of nursing staff per bed) (range 2.75 to 8). Annual caseload varied between units with the majority of units (49%) receiving between 25 and 50 patients with severe head injury, 23% receiving between 50 and 100 patients with severe head injury, and 29% receiving > 100 patients with severe head injury. There was considerable variability in both the nature of monitoring and therapy between centers. Although blood and central venous pressures were invasively monitored in > 50% of the patients in 94% and 77% of the centers, respectively, intracranial pressure was only monitored routinely in 57% of the centers. Jugular venous bulb oximetry, transcranial Doppler ultrasonography, electroencephalography, and near-infrared spectroscopy were rarely used. Nearly all centers used propofol and midazolam for sedation, with morphine, fentanyl, and alfentanil as the main analgesics. Muscle relaxation was commonly used, with 40% of the centers employing it in 100% of their patients. Atracurium and vecuronium were the most commonly used agents. Only 68% of the centers had a protocol for the treatment of intracranial hypertension. Although hyperventilation to a Paco2 of 26 to 30 torr (3.5 to 4.0 kPa) was the norm in the majority of centers (56%), two centers aimed for Paco2 values < 26 torr (< 3.5 kPa). A quarter of the units did not aim for a cerebral perfusion pressure of > 60 mm Hg. Mild hypothermia was rarely used and 14% of the centers continued to use corticosteroids for the treatment of intracranial hypertension as a result of head trauma.

CONCLUSION

We conclude that there are wide variations in the management of the severely head-injured patient in the UK and Ireland. Some of the therapies employed are not supported by available research findings. Rationalization (using rational management, i.e., based on good evidence) of the intensive care management of severe head injury with the development of widely accepted guidelines may result in an improvement in the quality of care of the head-injured patient.

Epidemiologic aspects of brain injury

Approximately 2 million head injuries occur each year in the United States, producing a brain injury rate of 175 to 200 per 100,000 population and causing as many as 56,000 deaths per year. The economic and emotional toll of this public health burden is staggering. By identifying risk factors, perhaps effective legislation and environmental and educational intervention strategies can be developed to prevent brain injury.

Multimodal monitoring in neurointensive care

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Cobalt-55 positron emission tomography in traumatic brain injury: a pilot study

Traumatic brain injury is usually assessed with the Glasgow coma scale (GCS), CT, or MRI. After such injury, the injured brain tissue is characterised by calcium mediated neuronal damage and inflammation. Positron emission tomography with the isotope cobalt-55 (Co-PET) as a calcium tracer enables imaging of affected tissue in traumatic brain injury. The aim was to determine whether additional information can be gained by Co-PET in the diagnosis of moderate traumatic brain injury and to assess any prognostic value of Co-PET. Five patients with recent moderately severe traumatic brain injury were studied. CT was performed on the day of admission, EEG within one week, and MRI and Co-PET within four weeks of injury. Clinical assessment included neurological examination, GCS, neuropsychological testing, and Glasgow outcome scale (GOS) after one year. Co-PET showed focal uptake that extended beyond the morphological abnormalities shown by MRI and CT, in brain regions that were actually diagnosed with EEG. Thus Co-PET is potentially useful for diagnostic localisation of both structural and functional abnormalities in moderate traumatic brain injury.