The Brain Trauma Foundation. The American Association of Neurological Surgeons. The Joint Section on Neurotrauma and Critical Care. Resuscitation of blood pressure and oxygenation

Management of Hemorrhagic Shock: Physiology Approach, Timing and Strategies

Hemorrhagic shock (HS) management is based on a timely, rapid, definitive source control of bleeding/s and on blood loss replacement. Stopping the hemorrhage from progressing from any named and visible vessel is the main stem fundamental praxis of efficacy and effectiveness and an essential, obligatory, life-saving step. Blood loss replacement serves the purpose of preventing ischemia/reperfusion toxemia and optimizing tissue oxygenation and microcirculation dynamics. The "physiological classification of HS" dictates the timely management and suits the 'titrated hypotensive resuscitation' tactics and the 'damage control surgery' strategy. In any hypotensive but not yet critical shock, the body's response to a fluid load test determines the cut-off point between compensation and progression between the time for adopting conservative treatment and preparing for surgery or rushing to the theater for rapid bleeding source control. Up to 20% of the total blood volume is given to refill the unstressed venous return volume. In any critical level of shock where, ab initio, the patient manifests signs indicating critical physiology and impending cardiac arrest or cardiovascular accident, the balance between the life-saving reflexes stretched to the maximum and the insufficient distal perfusion (blood, oxygen, and substrates) remains in a liable and delicate equilibrium, susceptible to any minimal change or interfering variable. In a cardiac arrest by exsanguination, the core of the physiological issue remains the rapid restoration of a sufficient venous return, allowing the heart to pump it back into systemic circulation either by open massage via sternotomy or anterolateral thoracotomy or spontaneously after aorta clamping in the chest or in the abdomen at the epigastrium under extracorporeal resuscitation and induced hypothermia. This is the only way to prevent ischemic damage to the brain and the heart. This is accomplishable rapidly and efficiently only by a direct approach, which is a crush laparotomy if the bleeding is coming from an abdominal +/- lower limb site or rapid sternotomy/anterolateral thoracotomy if the bleeding is coming from a chest +/- upper limbs site. Without first stopping the bleeding and refilling the heart, any further exercise is doomed to failure. Direct source control via laparotomy/thoracotomy, with the concomitant or soon following venous refilling, are the two essential, initial life-saving steps.

Effects of Preinjury and Postinjury Exposure to Caffeine in a Rat Model of Traumatic Brain Injury

Background: Lethal apnea is a significant cause of acute mortality following a severe traumatic brain injury (TBI). TBI is associated with a surge of adenosine, which also suppresses respiratory function in the brainstem. Methods and Materials: This study examined the acute and chronic effects of caffeine, an adenosine receptor antagonist, on acute mortality and morbidity after fluid percussion injury. Results: We demonstrate that, regardless of preinjury caffeine exposure, an acute bolus of caffeine given immediately following the injury dosedependently prevented lethal apnea and has no detrimental effects on motor performance following sublethal injuries. Finally, we demonstrate that chronic caffeine treatment after injury, but not caffeine withdrawal, impairs recovery of motor function. Conclusions: Preexposure of the injured brain to caffeine does not have a major impact on acute and delayed outcome parameters; more importantly, a single acute dose of caffeine after the injury can prevent lethal apnea regardless of chronic caffeine preexposure.

Safety and feasibility of minocycline in treatment of acute traumatic brain injury

BACKGROUND

Minocycline is a pleomorphic neuroprotective agent well studied in animal models of traumatic brain injury (TBI) and brain ischemia.

METHODS

To test the hypothesis that administration of minocycline in moderate to severe TBI (Glasgow Coma Score 3-12). Fifteen patients were enrolled in a two-dose escalation study of minocycline to evaluate the safety of twice the recommended antibiotic dosage; tier 1 n = 7 at a loading dose of 800 mg followed by 200 mg twice a day (BID) for 7 days; tier 2 n = 8 at a loading dose of 800 mg followed by 400 mg BID for 7 days.

RESULTS

The mean initial GCS was 5.6 for Tier 1 patients and 5.4 for Tier 2. The Disability Rating Scale (DRS) had a trend towards improvement with the higher dose 12.5 SD ± 7.7 (N = 5) for Tier 1 at 4 weeks and 8.5 SD ± 9.9 at week 12 (N = 5), whereas for Tier 2 it was 9.7 ± 6.9 (N = 6) for week 4 and 6.0 SD ± 6.1 (N = 7) for week 12 (p = .251 repeated measures ANOVA). Liver function tests increased but resolved after the first week and there were no infections.

CONCLUSIONS

Minocycline was safe for moderate to severe TBI at a dose twice that as recommended for treatment of infection. The higher dose did trend towards an improved outcome.

Physiological complexity of acute traumatic brain injury in patients treated with a brain oxygen protocol: utility of symbolic regression in predictive modeling of a dynamical system

Predictive modeling of emergent behavior, inherent to complex physiological systems, requires the analysis of large complex clinical data streams currently being generated in the intensive care unit. Brain tissue oxygen protocols have yielded outcome benefits in traumatic brain injury (TBI), but the critical physiological thresholds for low brain oxygen have not been established for a dynamical patho-physiological system. High frequency, multi-modal clinical data sets from 29 patients with severe TBI who underwent multi-modality neuro-clinical care monitoring and treatment with a brain oxygen protocol were analyzed. The inter-relationship between acute physiological parameters was determined using symbolic regression (SR) as the computational framework. The mean patient age was 44.4±15 with a mean admission GCS of 6.6±3.9. Sixty-three percent sustained motor vehicle accidents and the most common pathology was intra-cerebral hemorrhage (50%). Hospital discharge mortality was 21%, poor outcome occurred in 24% of patients, and good outcome occurred in 56% of patients. Criticality for low brain oxygen was intracranial pressure (ICP) ≥22.8 mm Hg, for mortality at ICP≥37.1 mm Hg. The upper therapeutic threshold for cerebral perfusion pressure (CPP) was 75 mm Hg. Eubaric hyperoxia significantly impacted partial pressure of oxygen in brain tissue (PbtO2) at all ICP levels. Optimal brain temperature (Tbr) was 34-35°C, with an adverse effect when Tbr≥38°C. Survivors clustered at [Formula: see text] Hg vs. non-survivors [Formula: see text] 18 mm Hg. There were two mortality clusters for ICP: High ICP/low PbtO2 and low ICP/low PbtO2. Survivors maintained PbtO2 at all ranges of mean arterial pressure in contrast to non-survivors. The final SR equation for cerebral oxygenation is: [Formula: see text]. The SR-model of acute TBI advances new physiological thresholds or boundary conditions for acute TBI management: PbtO2≥25 mmHg; ICP≤22 mmHg; CPP≈60-75 mmHg; and Tbr≈34-37°C. SR is congruous with the emerging field of complexity science in the modeling of dynamical physiological systems, especially during pathophysiological states. The SR model of TBI is generalizable to known physical laws. This increase in entropy reduces uncertainty and improves predictive capacity. SR is an appropriate computational framework to enable future smart monitoring devices.

Hemorrhagic shock: The "physiology approach"

A shift of approach from ‘clinics trying to fit physiology’ to the one of ‘physiology to clinics’, with interpretation of the clinical phenomena from their physiological bases to the tip of the clinical iceberg, and a management exclusively based on modulation of physiology, is finally surging as the safest and most efficacious philosophy in hemorrhagic shock. ATLS^® classification and recommendations on hemorrhagic shock are not helpful because antiphysiological and potentially misleading. Hemorrhagic shock needs to be reclassified in the direction of usefulness and timing of intervention: in particular its assessment and management need to be tailored to physiology.

Treatment of traumatic brain injury using zinc-finger protein gene therapy targeting VEGF-A

Vascular endothelial growth factor (VEGF) plays a role in angiogenesis and has been shown to be neuroprotective following central nervous system trauma. In the present study we evaluated the pro-angiogenic and neuroprotective effects of an engineered zinc-finger protein transcription factor transactivator targeting the vascular endothelial growth factor A (VEGF-ZFP). We used two virus delivery systems, adeno-virus and adeno-associated virus, to examine the effects of early and delayed VEGF-A upregulation after brain trauma, respectively. Male Sprague-Dawley rats were subject to a unilateral fluid percussion injury (FPI) of moderate severity (2.2-2.5 atm) followed by intracerebral microinjection of either adenovirus vector (Adv) or an adeno-associated vector (AAV) carrying the VEGF-ZFP construct. Adv-VEGF-ZFP-treated animals had significantly fewer TUNEL positive cells in the injured penumbra of the cortex (p<0.001) and hippocampus (p=0.001) relative to untreated rats at 72 h post-injury. Adv-VEGF-ZFP treatment significantly improved fEPSP values (p=0.007) in the CA1 region relative to injury alone. Treatment with AAV2-VEGF-ZFP resulted in improved post-injury microvascular diameter and improved functional recovery on the balance beam and rotarod task at 30 days post-injury. Collectively, the results provide supportive evidence for the concept of acute and delayed treatment following TBI using VEGF-ZFP to induce angiogenesis, reduce cell death, and enhance functional recovery.

Caffeine prevents acute mortality after TBI in rats without increased morbidity

Severe traumatic brain injury (TBI) is associated with a high incidence of acute mortality followed by chronic alteration of homeostatic network activity that includes the emergence of posttraumatic seizures. We hypothesized that acute and chronic outcome after severe TBI critically depends on disrupted bioenergetic network homeostasis, which is governed by the availability of the brain's endogenous neuroprotectant adenosine. We used a rat lateral fluid percussion injury (FPI) model of severe TBI with an acute mortality rate of 46.7%. A subset of rats was treated with 25mg/kg caffeine intraperitoneally within 1 min of the injury. We assessed neuromotor function at 24h and 4 weeks, and video-EEG activity and histology at 4 weeks following injury. We first demonstrate that acute mortality is related to prolonged apnea and that a single acute injection of the adenosine receptor antagonist caffeine can completely prevent TBI-induced mortality when given immediately following the TBI. Second, we demonstrate that neuromotor function is not affected by caffeine treatment at either 24h or 4 weeks following injury. Third, we demonstrate development of epileptiform EEG bursts as early as 4 weeks post-injury that are significantly reduced in duration in the rats that received caffeine. Our data demonstrate that acute treatment with caffeine can prevent lethal apnea following fluid percussion injury, with no negative influence on motor function or histological outcome. Further, we show epileptiform bursting is reduced after caffeine treatment, suggesting a potential role in the modulation of epilepsy development after severe injury.

Response to intracranial hypertension treatment as a predictor of death in patients with severe traumatic brain injury

Object

The normalization of increased intracranial pressure (ICP) in patients with severe traumatic brain injury (TBI) is assumed to limit secondary brain injury and improve outcome. Despite evidence-based recommendations for monitoring and treatment of elevated ICP, there are few studies that show an association between response to ICP-directed therapeutic regimens and adjusted mortality rate. This study utilizes a large prospective database to examine the effect of response to ICP-lowering therapy on risk of death within the first 2 weeks of injury in patients who sustained TBI and are older than 16 years.

Methods

The current study is based on 1426 patients with severe TBI (Glasgow Coma Scale [GCS] score < 9) of whom 388 were treated for elevated ICP (> 25 mm Hg) between 2000 and 2008 at 22 trauma centers enrolled in a New York State quality improvement program. This prospectively collected database also contains information including age, admission GCS score, pupillary status, CT scanning parameters, and hypotension, which are all known early prognostic indicators of death. Treatment of elevated ICP consisted of administration of mannitol, hypertonic saline, barbiturates, and/or drainage of CSF or decompressive craniectomy. The factors predicting ICP response to treatment and predicting death at 2 weeks were evaluated using logistic regression analyses.

Results

Increasing age and fewer hours of elevated ICP on Day 1 were found to be significant predictors (p = 0.001 and 0.0003, respectively) of a positive response to treatment. Response to ICP-lowering therapy (p = 0.03), younger age (p < 0.0001), fewer hours of elevated ICP (p < 0.0001), and absence of arterial hypotension on Day 1 (p = 0.001) significantly predicted reduced risk of death.

Conclusions

Patients who responded to ICP-lowering treatment had a 64% lower risk of death at 2 weeks than those who did not respond after adjusting for factors that independently predict risk of death.

Impact of injury location and severity on posttraumatic epilepsy in the rat: role of frontal neocortex

Human posttraumatic epilepsy (PTE) is highly heterogeneous, ranging from mild remitting to progressive disabling forms. PTE results in simple partial, complex partial, and secondarily generalized seizures with a wide spectrum of durations and semiologies. PTE variability is thought to depend on the heterogeneity of head injury and patient's age, gender, and genetic background. To better understand the role of these factors, we investigated the seizures resulting from calibrated fluid percussion injury (FPI) to adolescent male Sprague-Dawley rats with video electrocorticography. We show that PTE incidence and the frequency and severity of chronic seizures depend on the location and severity of FPI. The frontal neocortex was more prone to epileptogenesis than the parietal and occipital, generating earlier, longer, and more frequent partial seizures. A prominent limbic focus developed in most animals, regardless of parameters of injury. Remarkably, even with carefully controlled injury parameters, including type, severity, and location, the duration of posttraumatic apnea and the age and gender of outbred rats, there was great subject-to-subject variability in frequency, duration, and rate of progression of seizures, indicating that other factors, likely the subjects' genetic background and physiological states, have critical roles in determining the characteristics of PTE.

NEAR-CONTINUOUS, NONINVASIVE BLOOD PRESSURE MONITORING IN THE OUT-OF-HOSPITAL SETTING

OBJECTIVES

This study was conducted to test out-of-hospital performance of a noninvasive radial artery tonometry device to assess blood pressure (BP), providing readings every 10-12 seconds. The primary objective was to determine the correlation between noninvasive BPs calculated with radial artery tonometry and standard oscillometric cuff methods. The secondary objective was to determine whether the difference observed between the two techniques was consistent over the range of BPs measured.

METHODS

This prospective trial enrolled adults transported by helicopter (n = 9 patients), fixed-wing airplane (n = 1), or ground vehicle (n = 10) of a single transport service. Patients had BP assessed simultaneously, by both standard automatic cuff and radial artery tonometry device, every 5 minutes. Data were assessed with correlation coefficients, and Bland-Altman techniques were utilized to assess for bias over the range of mean arterial pressures (MAPs) encountered. For all tests, p was set at 0.05.

RESULTS

No major problem with radial artery tonometry device field performance was noted. There were 139 pairs of MAP assessments in 20 patients. The correlation coefficient for the two assessment modalities was 0.96. Bland-Altman bias plot and Pitman's test (p = 0.11) revealed good correlation between the two assessment mechanisms over the entire range of MAPs (42 to 163 mm Hg) encountered in the study.

CONCLUSION

The radial artery tonometry device provided MAP assessments that were highly correlated with readings from a standard oscillometric device. The radial artery tonometry device performed well in a variety of patient types and in multiple transport vehicles, and there was no sign that its performance was adversely affected by the out-of-hospital setting.

Molecular mechanisms of traumatic brain injury in children. A review

Despite advances in molecular biology and genetics, the precise pathophysiology of traumatic brain injury (TBI) in children is unknown. In this paper the authors review what is currently known about intra- and extracellular responses to pediatric TBI and relate these factors to future investigations. Although hyperemia and vascular congestion have long been thought to be the hallmarks of pediatric TBI, on a cellular level, calcium influx as well as modulation of local neurotransmitters appears to play a major role in its onset. Recent genetic and proteomic research has identified specific neurotrophic factors as well as apoptotic and antiapoptotic genes that appear to control the progression of inflammation and neuronal damage. The search for a therapeutic target will ultimately require a thorough understanding of these factors and their interplay on a proteomic, genomic, and neuromic level.

The Role of Hypotensive Resuscitation in the Management of Trauma

The primary objective of trauma care is to minimise or reverse shock thus saving life. Aggressive fluid resuscitation may be harmful in these patients because the resulting increased blood pressure and circulating volume may cause clot disruption, dilution of clotting factors and/or the reversal of the body's natural response to haemorrhage. The concept of hypotensive resuscitation has evolved where small aliquots of fluid are infused, with hypovolaemia and hypotension tolerated as a necessary evil until definitive haemorrhage control can be achieved. This review outlines the animal and human data to support the strategy of hypotensive resuscitation.

An analysis of regional microvascular loss and recovery following two grades of fluid percussion trauma: a role for hypoxia-inducible factors in traumatic brain injury

Secondary hypoxic/ischemic injuries, stemming from reductions in cerebral blood flow are important contributing factors in progressive neuronal dysfunction after brain trauma. A greater preclinical understanding of how brain trauma leads to secondary hypoxia/ischemia is necessary in the development of posttraumatic brain injury (TBI) therapeutics. To this end, we examined the density of microvascular coverage in the injured and contralateral cortical hemispheres using two intensities of fluid percussion trauma in rats. A silicone microangiography technique showed a significant loss in microvascular density in 2 atmosphere (atm) (16.9+/-3.8%) and 3 atm (15.7+/-1.3%) injured animals relative to sham animals (29.9+/-2.5%; P<0.01). RECA-1 immunohistochemistry indicated that capillary changes involved a reduction in capillary number and diameter. Reduction in microvascular density was shown to be a diffuse phenomenon occurring up to 4 mm rostral and caudal to the injury epicenter. Recovery of microvasculature occurred by 2 weeks after injury only in the 2 atm injury group. Expression of HIF1alpha and increased vascular endothelial growth factor expression were observed in the ipsilateral hippocampus suggesting sufficiently impaired microcirculation resulting in the expression of hypoxic-response proteins. Collectively, the results indicate diffuse and heterogeneous microvascular alterations as well as endogenous expression of neuroprotective and neovascularization pathways after TBI.

Long-term outcomes and prognostic factors in pediatric patients with severe traumatic brain injury and elevated intracranial pressure

OBJECT

The management strategies and outcomes in pediatric patients with elevated intracranial pressure (ICP) following severe traumatic brain injury (TBI) are examined in this study.

METHODS

This study was a retrospective review of a prospectively acquired pediatric trauma database. More than 750 pediatric patients with brain injury were seen over a 10-year period. Records were retrospectively reviewed to determine interventions for correcting ICP, and surviving patients were contacted prospectively to determine functional status and quality of life. Only patients with 2 years of follow-up were included in the study.

RESULTS

Ninety-six pediatric patients (age range 3-18 years) were identified with a Glasgow Coma Scale score<8 and elevated ICP>20 mm Hg on presentation. The mean injury severity score was 65 (range 30-100). All patients were treated using a standardized head injury protocol. The mean time course until peak ICP was 69 hours postinjury (range 2-196 hours). Intracranial pressure control was achieved in 82 patients (85%). Methods employed to achieve ICP control included maximal medical therapy (sedation, hyperosmolar therapy, and paralysis) in 34 patients (35%), ventriculostomy in 23 patients (24%), and surgery in 39 patients (41%). Fourteen patients (15%) had refractory ICP despite all interventions, and all of these patients died. Seventy-two patients (75%) were discharged from the hospital, whereas 24 (25%) died during hospitalization. Univariate and multivariate analysis revealed that the presence of vascular injury, refractory ICP, and cisternal effacement at presentation had the highest correlation with subsequent death (p<0.05). Mean follow-up was 53 months (range 11-126 months). Three patients died during the follow-up period (2 due to infections and 1 committed suicide). The mean 2-year Glasgow Outcome Scale score was 4 (median 4, range 1-5). The mean patient competency rating at follow-up was 4.13 out of 5 (median 4.5, range 1-4.8). Univariate analysis revealed that the extent of intracranial and systemic injuries had the highest correlation with long-term quality of life (p<0.05).

CONCLUSIONS

Controlling elevated ICP is an important factor in patient survival following severe pediatric TBI. The modality used for ICP control appears to be less important. Long-term follow-up is essential to determine neurocognitive sequelae associated with TBI.

Normoxic ventilatory resuscitation following controlled cortical impact reduces peroxynitrite-mediated protein nitration in the hippocampus

OBJECTIVES

Ventilatory resuscitation with 100% O2 after severe traumatic brain injury (TBI) raises concerns about the increased production of reactive oxygen species (ROS). The product of peroxynitrite-meditated tyrosine residue nitration, 3-nitrotyrosine (3-NT), is a marker for oxidative damage to proteins. The authors hypothesized that posttraumatic resuscitation with hyperoxia (100% fraction of inspired oxygen [FiO2] concentration) results in increased ROS-induced damage to proteins compared with resuscitation using normoxia (21% FiO2 concentration).

METHODS

Male Sprague-Dawley rats underwent controlled cortical impact (CCI) injury and resuscitation with either normoxic or hyperoxic ventilation for 1 hour (5 rats per group). Twenty-four hours after injury, rat hippocampi were evaluated using 3-NT immunostaining. In a second experiment, animals similarly underwent CCI injury and normoxic or hyperoxic ventilation for 1 hour (4 rats per group). One week after injury, neuronal counts were performed after neuronal nuclei immunostaining.

RESULTS

The 3-NT staining was significantly increased in the hippocampi of the hyperoxic group. The normoxic group showed a 51.0% reduction of staining in the CA1 region compared with the hyperoxic group and a 50.8% reduction in the CA3 region (p < 0.05, both regions). There was no significant difference in staining between the injured normoxic group and sham-operated control groups. In the delayed analysis of neuronal survival (neuronal counts), there was no significant difference between the hyperoxic and normoxic groups.

CONCLUSIONS

In this clinically relevant model of TBI, normoxic resuscitation significantly reduced oxidative damage to proteins compared with hyperoxic resuscitation. Neuronal counts showed no benefit from hyperoxic resuscitation. These findings indicate that hyperoxic ventilation in the early stages after severe TBI may exacerbate oxidative damage to proteins.

The role of evidence-based medicine in neurosurgery

Evidence-based medicine (EBM) has become one of the pillars of modern medicine. There are many myths and misconceptions about EBM that retard its application into neurosurgical practice. We aim to dispel some of these. Neurosurgeons should cultivate sound EBM practice and strive to improve the available evidence base for neurosurgery. Although randomised controlled trials are not suitable to investigate many neurosurgical problems, this does not preclude practising EBM that requires consideration of the strongest available evidence at the time of clinical decision making. Although individualised analysis of primary sources of evidence gives the clearest analysis, the diversity and complexity of modern medicine means that it is difficult for clinicians to stay abreast of all EBM through this mechanism alone. The development of evidence-based practice guidelines by neurosurgeons is a practical alternative. We recommend that neurosurgical organisations and societies take up this challenge and develop EBM education programs, encouraging the practise of EBM by neurosurgeons and neurosurgical trainees.

Saline or albumin for fluid resuscitation in patients with traumatic brain injury

BACKGROUND

The Saline versus Albumin Fluid Evaluation study suggested that patients with traumatic brain injury resuscitated with albumin had a higher mortality rate than those resuscitated with saline. We conducted a post hoc follow-up study of patients with traumatic brain injury who were enrolled in the study.

METHODS

For patients with traumatic brain injury (i.e., a history of trauma, evidence of head trauma on a computed tomographic [CT] scan, and a score of < or =13 on the Glasgow Coma Scale [GCS]), we recorded baseline characteristics from case-report forms, clinical records, and CT scans and determined vital status and functional neurologic outcomes 24 months after randomization.

RESULTS

We followed 460 patients, of whom 231 (50.2%) received albumin and 229 (49.8%) received saline. The subgroup of patients with GCS scores of 3 to 8 were classified as having severe brain injury (160 [69.3%] in the albumin group and 158 [69.0%] in the saline group). Demographic characteristics and indexes of severity of brain injury were similar at baseline. At 24 months, 71 of 214 patients in the albumin group (33.2%) had died, as compared with 42 of 206 in the saline group (20.4%) (relative risk, 1.63; 95% confidence interval [CI], 1.17 to 2.26; P=0.003). Among patients with severe brain injury, 61 of 146 patients in the albumin group (41.8%) died, as compared with 32 of 144 in the saline group (22.2%) (relative risk, 1.88; 95% CI, 1.31 to 2.70; P<0.001); among patients with GCS scores of 9 to 12, death occurred in 8 of 50 patients in the albumin group (16.0%) and 8 of 37 in the saline group (21.6%) (relative risk, 0.74; 95% CI, 0.31 to 1.79; P=0.50).

CONCLUSIONS

In this post hoc study of critically ill patients with traumatic brain injury, fluid resuscitation with albumin was associated with higher mortality rates than was resuscitation with saline. (Current Controlled Trials number, ISRCTN76588266 [controlled-trials.com].).

[Management of severe traumatic brain injury]

Severe brain injuries, most often occurring in young subjects, are a major source of lost work years. These injuries are medical and surgical emergencies. Prehospital management of severe brain injuries requires intubation and mechanical ventilation aimed at normal arterial carbon dioxide pressure. Signs of transtentorial herniation: Uni- or bilateral mydriasis requires immediate perfusion of 20% mannitol or hypertonic sodium chloride. Neurological disorders after head injury justify emergency cerebral computed tomography. The presence of a mass syndrome or signs of transtentorial herniation are in principle indications for surgery. Specialized hospital management is essential. In the case of refractory intracranial hypertension, the cerebral perfusion pressure and osmotherapy should be adapted to the volume of the cerebral contusion. The use of deep hypothermia and barbiturates should be minimized as much as possible. Magnetic resonance imaging makes it possible to identify the cerebral lesions.

Cerebellar injury: clinical relevance and potential in traumatic brain injury research

A treatment for traumatic brain injury (TBI) remains elusive despite compelling evidence from animal models for a variety of therapeutic targets. Numerous animal models have been developed to address the wide spectrum of mechanisms involved in the progression of secondary injury after TBI. Evidence from well-established models such as the fluid percussion injury (FPI) device, cortical impact model, and the impact acceleration model has demonstrated diffuse pathophysiological mechanisms throughout various brain structures. More specifically, we have recently extended characterization of the FPI model to include pathophysiological changes in the cerebellum following unilateral fluid percussion. Data suggest that the cerebellum is susceptible to selective Purkinje cell loss as well as white matter dysfunction. Despite the cerebellum's low profile in TBI research, there is evidence to warrant further study of the cerebellum to examine mechanisms of neuronal death and traumatic axonal injury. Furthermore, evidence from clinical literature and basic science suggests that some components of TBI pathophysiology have a basis in cerebellar dysfunction. This review highlights some of the recent findings in cerebellar trauma and builds an argument for including the cerebellum as a model to assess mechanisms of secondary injury and its potential contribution to the pathology of TBI.

Effect of pre-hospital advanced life support with rapid sequence intubation on outcome of severe traumatic brain injury

BACKGROUND

The role of pre-hospital trauma care and the effect of pre-hospital rapid sequence intubation (RSI) on patient outcome are still not clear. This study evaluated the impact of pre-hospital trauma care by emergency physicians (EP) on mortality from severe traumatic brain injury (TBI) and a 180-day Glasgow Outcome Scale (GOS).

METHODS

A 48-month parallel non-controlled cohort study compared a group of 64 patients with severe TBI [Glasgow Coma Scale (GCS) < 9; Injury Severity Score (ISS) > 15] who received pre-hospital advanced life support (ALS) with RSI and were transported to the hospital by EPs (EP group), with a group of 60 patients who did not receive pre-hospital ALS with RSI [emergency medical technicians (EMT) group].

RESULTS

There were no significant statistical differences between the groups in age (P= 0.79), mechanism of injury (P= 0.68), gender (P= 0.82), initial GCS (P= 0.63), initial SaO(2) in the field (P= 0.63), initial systolic blood pressure in the field (P= 0.47) and on-scene time (P= 0.41). In the EP group, there was significantly better first hour survival (97% vs. 79%, P= 0.02), first day survival (90% vs. 72%, P= 0.02), better functional outcome (GOS 4-5: 53% vs. 33%, P < 0.01; GOS 2-3: 8% vs. 20%, P < 0.01) and shortened hospitalization time in intensive care unit (ICU) (P= 0.03) and other departments (P= 0.04). In total hospital mortality, we detected no differences between both groups [EP group: 40% (95% CI: 34-45%) vs. EMT group 42% (95% CI: 36-47%, P= 0.76], except in a subgroup of patients with GCS 6-8 where there was significantly lower total hospital mortality in the EP group (24% vs. 78%, P < 0.01).

CONCLUSION

After starting the trauma care system with emergency physicians in our region, there was a decrease in the number of deaths on hospital admission, a reduction in hospital mortality in the GCS group 6-8, a change in the temporal distribution of deaths, an improvement in functional neurological outcome and shortened hospitalization time.

Initial resuscitation of hemorrhagic shock

The primary treatment of hemorrhagic shock is control of the source of bleeding as soon as possible and fluid replacement. In controlled hemorrhagic shock (CHS) where the source of bleeding has been occluded fluid replacement is aimed toward normalization of hemodynamic parameters. In uncontrolled hemorrhagic shock (UCHS) in which bleeding has temporarily stopped because of hypotension, vasoconstriction, and clot formation, fluid treatment is aimed at restoration of radial pulse, or restoration of sensorium or obtaining a blood pressure of 80 mmHg by aliquots of 250 ml of lactated Ringer's solution (hypotensive resuscitation). When evacuation time is shorter than one hour (usually urban trauma) immediate evacuation to a surgical facility is indicated after airway and breathing (A, B) have been secured ("scoop and run"). Precious time is not wasted by introducing an intravenous line. When expected evacuation time exceeds one hour an intravenous line is introduced and fluid treatment started before evacuation.

Crystalloid solutions and blood transfusion are the mainstays of pre-hospital and in-hospital treatment of hemorrhagic shock. In the pre-hospital setting four types of fluid are presently recommended: crystalloid solutions, colloid solutions, hypertonic saline and oxygen-carrying blood substitutes. In unstable or unresponsive hemorrhagic shock surgical treatment is mandatory as soon as possible to control the source of bleeding.

Effects of arginine vasopressin during resuscitation from hemorrhagic hypotension after traumatic brain injury

OBJECTIVE

Two series of experiments were designed to evaluate whether early arginine vasopressin improves acute outcome following resuscitation from traumatic brain injury and severe hemorrhagic hypotension.

DESIGN

Prospective randomized, blinded animal study.

SETTING

University laboratory.

SUBJECTS

Thirty-three swine.

INTERVENTIONS

In series 1 (n = 19), after traumatic brain injury with hemorrhage and 12 mins of shock (mean arterial pressure approximately 20 mm Hg), survivors (n = 16) were initially resuscitated with 10 mL/kg crystalloid. After 30 mins, crystalloid and blood with either 0.1 unit x kg(-1) x hr(-1) arginine vasopressin or placebo was titrated to a mean arterial pressure target >or=60 mm Hg. After 90 mins, all received mannitol and the target was cerebral perfusion pressure >or=60 mm Hg. To test cerebrovascular function, 7.5% inhaled CO2 was administered periodically. In series 2 (n = 14), the identical protocol was followed except the shock period was 20 mins and survivors (n = 10) received a bolus of either arginine vasopressin (0.2 units/kg) or placebo during the initial fluid resuscitation.

MEASUREMENTS AND MAIN RESULTS

In series 1, by 300 mins after traumatic brain injury with arginine vasopressin (n = 8) vs. placebo (n = 8), the fluid and transfusion requirements were reduced (both p < .01), intracranial pressure was improved (11 +/- 1 vs. 23 +/- 2 mmHg; p < .0001), and the CO2-evoked intracranial pressure elevation was reduced (7 +/- 2 vs. 26 +/- 3 mm Hg, p < .001), suggesting improved compliance. In series 2, with arginine vasopressin vs. placebo, cerebral perfusion pressure was more rapidly corrected (p < .05). With arginine vasopressin, five of five animals survived 300 mins, whereas three of five placebo animals died. The survival time with placebo was 54 +/- 4 mins (p < .05 vs. arginine vasopressin).

CONCLUSIONS

Early supplemental arginine vasopressin rapidly corrected cerebral perfusion pressure, improved cerebrovascular compliance, and prevented circulatory collapse during fluid resuscitation of hemorrhagic shock after traumatic brain injury.

Hypotension Does Not Increase Mortality in Brain-Injured Patients More Than it Does in Non-Brain-Injured Patients

OBJECTIVES

Hypotension increases mortality after all types of injuries. Prior studies comparing mortality of hypotensive traumatic brain injury (TBI) patients to normotensive TBI patients have implied that hypotension is particularly detrimental after TBI. It is unknown whether hypotension affects TBI patients more severely than it affects other types of patients. We hypothesized that hypotension does not increase mortality in TBI patients more than it does in non-TBI patients.

METHODS

National Trauma Data Bank (1994-2002) patients aged 18 to 45 years with blunt mechanisms of injury treated at Level I and Level II centers were included. Deaths occurring before 24 hours were excluded. Logistic regression was used to measure the association between hypotension (< or =90 mm Hg) and death after adjusting for confounding variables of age, gender, comorbidities, complications, Glasgow Coma Scale score, and severity of associated injuries. Odds ratios (95% confidence interval) indicate the risk of death in hypotensive patients in each group compared with normotensive patients in the same group.

RESULTS

The study population consisted of 79,478 patients (TBI, 30,742; no TBI, 48,736). Hypotension independently quadrupled the risk of death after adjusting for confounding variables (odds ratio [OR], 4.8; 95% confidence interval [CI], 4.1-5.6). However, increase in this risk associated with hypotension was the same in TBI (OR, 4.1; 95% CI, 3.5-4.9) and non-TBI patients (OR, 4.6; 95% CI, 3.4-6.0). Furthermore, the relationship between hypotension and TBI did not change with increasing head Abbreviated Injury Scale score severity.

CONCLUSION

Hypotension is an independent risk factor for mortality. However, it does not increase mortality in TBI patients more than it does for non-TBI patients.

Primer on medical management of severe brain injury

OBJECTIVE

To review the current understanding of the medical management of severe brain injury.

DATA SOURCE

The MEDLINE database, bibliographies of selected articles, and current English-language texts on the subject.

STUDY SELECTION

Studies related to management of intracranial hypertension, traumatic brain injury, and brain edema.

DATA EXTRACTION

All studies relevant to the subject under consideration were considered, with a focus on clinical studies in adults.

DATA SYNTHESIS

Basic rules of resuscitation must apply, including adequate ventilation, appropriate fluid administration, and cardiovascular support. The control of intracranial pressure can be considered in three steps. The first step should be initial slight hyperventilation with a target PaCO2 of 35 mm Hg and cerebrospinal fluid drainage for intracranial pressure of >15-20 mm Hg. The second step should be mannitol or hypertonic saline and hyperventilation to target PaCO2 of 28-35 mm Hg. The third step should be barbiturate coma or decompressive craniectomy. Additional management issues, including seizure prophylaxis, sedation, nutritional support, use of hypothermia, and corticosteroids, are also discussed.

CONCLUSIONS

Brain injury is frequently associated with the development of brain edema and the development of intracranial hypertension. However, with a coordinated, stepwise, and aggressive approach to management, focusing on control of intracranial pressure without adversely affecting cerebral perfusion pressure, outcomes can be good.

Lateral fluid percussion brain injury: a 15-year review and evaluation

This article comprehensively reviews the lateral fluid percussion (LFP) model of traumatic brain injury (TBI) in small animal species with particular emphasis on its validity, clinical relevance and reliability. The LFP model, initially described in 1989, has become the most extensively utilized animal model of TBI (to date, 232 PubMed citations), producing both focal and diffuse (mixed) brain injury. Despite subtle variations in injury parameters between laboratories, universal findings are evident across studies, including histological, physiological, metabolic, and behavioral changes that serve to increase the reliability of the model. Moreover, demonstrable histological damage and severity-dependent behavioral deficits, which partially recover over time, validate LFP as a clinically-relevant model of human TBI. The LFP model, also has been used extensively to evaluate potential therapeutic interventions, including resuscitation, pharmacologic therapies, transplantation, and other neuroprotective and neuroregenerative strategies. Although a number of positive studies have identified promising therapies for moderate TBI, the predictive validity of the model may be compromised when findings are translated to severely injured patients. Recently, the clinical relevance of LFP has been enhanced by combining the injury with secondary insults, as well as broadening studies to incorporate issues of gender and age to better approximate the range of human TBI within study design. We conclude that the LFP brain injury model is an appropriate tool to study the cellular and mechanistic aspects of human TBI that cannot be addressed in the clinical setting, as well as for the development and characterization of novel therapeutic interventions. Continued translation of pre-clinical findings to human TBI will enhance the predictive validity of the LFP model, and allow novel neuroprotective and neuroregenerative treatment strategies developed in the laboratory to reach the appropriate TBI patients.

[Shock trauma room management of the multiple-traumatized patient with skull-brain injuries. A systematic review of the literature]

This overview reviews the literature on multiply injured patients with traumatic brain injuries. Clinical trials were systematically collected (MEDLINE, Cochrane, and hand searches) and classified into evidence levels (1 to 5 according to the Oxford system).A detailed analysis of the literature of traumatic brain injuries has been elaborated by the Brain Trauma Foundation and has been published in the World Wide Web (http://www2.braintrauma.org/). The following procedures should be performed in the emergency room for multiply injured patients with traumatic brain injuries: (1) recording of precise history to identify risk factors for severe traumatic brain injury, (2) measurement of the Glasgow Coma Scale (GCS), pupillary reflex, and mean arterial pressure, (3) diagnostic evaluation with a CT scan, and (4) rapid surgical decompression if indicated.

Management of brain and spine injuries

For both SCI and TBI, physicians are unable to affect reversal of the cellular injuries suffered at the time of trauma directly. Unfortunately, understanding such processes is just on the horizon. Physicians do, however, have significant influence on recovery through the avoidance of secondary insults to the injured nervous system. In keeping with trauma in general, the mechanism for this is focused and coordinated multi-disciplinary care originating at the earliest contact and continuing through acute care. Aggressive and pre-emptive attention to the ABC(D)s with attention to the needs of the injured nervous system, appropriate monitoring in all patients, meticulous medical management, and prompt surgical intervention when indicated have made marked improvements in outcome, particularly in TBI. Focusing on the basics and strict attention to detail appear to be the major roles played in the care of CNS trauma.

Blood Pressure and Outcome after Severe Pediatric Traumatic Brain Injury

BACKGROUND

The relationship between systolic blood pressure and outcome in children after severe traumatic brain injury (TBI) is unclear. We examined the relationship between age-appropriate systolic blood pressure (AASBP) percentile and outcome after severe pediatric TBI.

METHODS

We examined the association between AASBP percentiles and outcome in 172 children younger than 14 years of age with a Glasgow Coma Scale score < 9. Outcome was evaluated using discharge Glasgow Outcome Scale score. Poor outcome was defined as a Glasgow Outcome Scale score < 4.

RESULTS

Poor outcome was associated with AASBP < 75th percentile (odds ratio, 4.2; 95% confidence interval, 2.1-8.3). Patients with systolic blood pressure (SBP) > or = 90 mm Hg and AASBP < 75th percentile had a higher odds for poor outcome compared with patients with SBP > or = 90 mm Hg and AASBP > or = 75th percentile (odds ratio, 3.5; 95% confidence interval, 1.7-7.3). CONCLUSION AASBP < 75th percentile was associated with poor outcome after severe pediatric TBI, even when SBP was > or = 90 mm Hg.

Sedation in neurointensive care: advances in understanding and practice

PURPOSE OF REVIEW

To evaluate the rationale and the pharmacologic options for sedating neurointensive care patients.

RECENT FINDINGS

Sedation is a fundamental element in the neurointensive care unit. Even if the sedative strategy in the neurointensive care unit shares the same general aims with intensive care, the characteristics of the patients in the neurointensive care unit pose other unique challenges and some specific indications. The primary aim of neurointensive care is to maintain adequate cerebral perfusion pressure, to control intracranial pressure, and to maintain an adequate mean arterial pressure. Reducing the brain's metabolic demand is an important treatment strategy, and analgesic and sedative agents are used to prevent undesirable increases in intracranial pressure. There are many different pharmacologic agents available, each with distinct advantages and disadvantages.

SUMMARY

The pharmacokinetic and pharmacologic effects of the available sedatives used in neurointensive care patients are reviewed.

New neurophysiology and central nervous system dysfunction

PURPOSE OF REVIEW

The goal of this article is to summarize very recent technologic advances in neurophysiologic monitoring and to illustrate their potential benefit to critical care medicine.

RECENT FINDINGS

Simplified, computer-processed electroencephalography devices now permit cost-effective, long-term critical care monitoring. They may be used alone to objectively assess sedation or coma level. In addition, these monitors serve as screening tools for more detailed electrophysiologic characterization of cortical dysfunction resulting from seizures, ischemia, or hypoxia. Somatosensory potentials broaden these capabilities to the entire neuraxis, whereas long-latency auditory evoked potentials facilitate measurement of changes in vigilance and cognition. Motor evoked potentials offer a sensitive and reliable method to determine the function of descending motor pathways in uncooperative or unresponsive patients. They may also yield a new measure of cortical excitability. New developments with transcranial Doppler ultrasonography promise noninvasive measures of cerebral perfusion pressure and particulate embolization. Near-infrared spectroscopy appears to enable noninvasive measurement of regional tissue oxygenation in both the brain and spinal cord.

SUMMARY

When used together, these continuous measures of synaptic function, cerebral perfusion, and oxygenation give the clinician a vast amount of otherwise unobtainable information regarding the functional status of the central nervous system.

Critical care issues in stroke and subarachnoid hemorrhage

The outcomes of devastating neurological emergencies such as stroke and subarachnoid hemorrhage may be measurably improved by timely treatment in a neurointensive care unit (NICU). Optimal care requires a multidisciplinary approach, with attention to a wide range of treatment issues. This review examines the key therapeutic concerns in the NICU management of acute ischemic and hemorrhagic stroke and subarachnoid hemorrhage, including mechanical ventilation, blood pressure management, cardiac monitoring, intracranial pressure assessment, vasospasm, seizures, sedation, fluids, electrolytes, and nutrition. The discussion of mechanical ventilation includes rapid sequence induction and intubation, indication for intubation and extubation, and prognostic factors in mechanical ventilation. Differing blood pressure management concerns in hemorrhagic and ischemic events are discussed, and specific target blood pressures and pharmacologic interventions are reviewed. The discussion of cardiac monitoring includes concurrent stroke and cardiac ischemia and arrhythmias, cardiac imaging, anticoagulation, and vasopressor therapy. The importance, monitoring and management of cerebral blood flow and intracranial pressure (ICP) are discussed, and strategies for treatment of elevated ICP are outlined in detail. The discussion of vasospasm includes evaluation, prophylaxis, and treatment with medications, hypervolemic hemodilution, and angioplasty. Management of seizure and status epilepticus in stroke and subarachnoid hemorrhage are reviewed and current algorithms are presented. The management of fluids, electrolytes and enteral nutrition are also reviewed.

The use of rapid sequence intubation by ambulance paramedics for patients with severe head injury

OBJECTIVE

To determine the effects of rapid sequence intubation in patients with severe head injury performed by paramedics on a helicopter emergency medical service.

METHODS

The patient care records for patients with severe head injury who underwent rapid sequence intubation between November 1999 and February 2002 (inclusive) were examined. Data were extracted on the demographics of the patients, as well as the physiological changes before and after rapid sequence intubation.

RESULTS

There were 122 patients with severe head injury evaluated at the scene during the study period. Rapid sequence intubation was attempted in 110 patients and was successful in 107 (97%). Intubation was associated with improvements in systolic blood pressure, oxygen saturation and end-tidal carbon dioxide levels, compared with baseline levels.

CONCLUSION

Rapid sequence intubation in patients with severe head injury may be safely undertaken by helicopter-based ambulance paramedics and is associated with improvements in oxygenation, ventilation and blood pressure. Further studies of this skill undertaken by road-based paramedics are warranted.

Critical care management of head trauma in children

Trauma is the leading cause of both morbidity and mortality in the pediatric population, and traumatic injury causes > 50% of all childhood deaths. Significant mortality rates have been reported for children with traumatic brain injury. Although children have better survival rates as compared with adults with traumatic brain injury, the long-term sequelae and consequences are often more devastating in children due to their age and developmental potential. The costs involved in the care of a child with severe traumatic brain injury, extended over that child's lifetime, are significant. It is unfortunate that despite preventive measures, traumatic brain injury remains the major morbidity and mortality factor for children.

Pediatric trauma: postinjury care in the pediatric intensive care unit

Traumatic injuries occur in > 20 million children each year and are the leading source of death in children over the age of 1 yr. Mechanisms of injury and subsequent therapies for critically injured children are diverse. This review will focus on resources and management strategies for caring for the severely injured child in the pediatric intensive care unit.

Management of severe head injury: institutional variations in care and effect on outcome

OBJECTIVE

The purpose of this study was three-fold: a) to examine variations in care of patients with severe head injury in academic trauma centers across the United States; b) to determine the proportion of patients who received care according to the Brain Trauma Foundation guidelines; and c) to correlate the outcome from severe traumatic brain injury with the care received.

DESIGN

Retrospective data collection for consecutive patients with closed head injury and long bone fracture admitted over an 8-month period.

SETTING

Thirty-four academic trauma centers in the United States

PATIENTS

All patients admitted with a presenting Glasgow Coma Scale score < or = 8.

MEASUREMENTS AND MAIN RESULTS

Variations in care were assessed, including prehospital intubation, intracranial pressure monitoring, use of osmotic agents, hyperventilation, and computed tomography scan utilization. Aggressive centers were defined as those placing intracranial pressure monitors in >50% of patients meeting the Brain Trauma Foundation criteria for intracranial pressure monitoring. The primary outcome variables were mortality, functional status at discharge, and length of stay. Kaplan-Meier survival analysis was performed for aggressive vs. nonaggressive centers. A Cox proportional hazard model was used to evaluate the association between type of center and mortality rate. Length of stay was evaluated by using linear regression.

RESULTS

There was considerable variation in the rates of prehospital intubation, intracranial pressure monitoring, intracranial pressure-directed therapy, and head computed tomography scan utilization across centers. Management at an aggressive center was associated with a significant reduction in the risk of mortality (hazard ratio, 0.43; 95% confidence interval, 0.27-0.66). There was no statistically significant difference in functional status at the time of discharge for survivors. Adjusted length of stay for survivors at aggressive centers was shorter, compared with the length of stay at nonaggressive centers: -6 days (95% confidence interval, -14 to 2 days).

CONCLUSION

Considerable national variation in the care of severely head-injured patients persists. An "aggressive" management strategy is associated with decreased mortality rate for patients with severe head injury, with no significant difference in functional status at discharge among survivors.