Primer on medical management of severe brain injury

Brain Herniation and Intracranial Hypertension

This article introduces the basic concepts of intracranial physiology and pressure dynamics. It also includes discussion of signs and symptoms and examination and radiographic findings of patients with acute cerebral herniation as a result of increased as well as decreased intracranial pressure. Current best practices regarding medical and surgical treatments and approaches to management of intracranial hypertension as well as future directions are reviewed. Lastly, there is discussion of some of the implications of critical medical illness (sepsis, liver failure, and renal failure) and treatments thereof on causation or worsening of cerebral edema, intracranial hypertension, and cerebral herniation.

Pentobarbital Coma With Therapeutic Hypothermia for Treatment of Refractory Intracranial Hypertension in Traumatic Brain Injury Patients: A Single Institution Experience

Introduction Traumatic brain injury (TBI) results in primary and secondary brain injuries. Secondary brain injury can lead to cerebral edema resulting in increased intracranial pressure (ICP) secondary to the rigid encasement of the skull. Increased ICP leads to decreased cerebral perfusion pressure which leads to cerebral ischemia. Refractory intracranial hypertension (RICH) occurs when ICP remains elevated despite first-tier therapies such as head elevation, straightening of the neck, analgesia, sedation, paralytics, cerebrospinal fluid (CSF) drainage, mannitol and/or hypertonic saline administration. If unresponsive to these measures, second-tier therapies such as hypothermia, barbiturate infusion, and/or surgery are employed. Methods This was a retrospective review of patients admitted at Arrowhead Regional Medical Center from 2008 to 2019 for severe TBI who developed RICH requiring placement into a pentobarbital-induced coma with therapeutic hypothermia. Primary endpoints included mortality, good recovery which was designated at Glasgow outcome scale (GOS) of 4 or 5, and improvement in ICP (goal is <20 mmHg). Secondary endpoints included complications, length of intensive care unit (ICU) stay, length of hospital stay, length of pentobarbital coma, length of hypothermia, need for vasopressors, and decompressive surgery versus no decompressive surgery. Results Our study included 18 patients placed in pentobarbital coma with hypothermia for RICH. The overall mortality rate in our study was 50%; with 60% mortality in pentobarbital/hypothermia only group, and 46% mortality in surgery plus pentobarbital/hypothermia group. Maximum ICP prior to pentobarbital/hypothermia was significantly lower in patients who had a prior decompressive craniectomy than in patients who were placed into pentobarbital/hypothermia protocol first (28.3 vs 35.4, p<0.0238). ICP was significantly reduced at 4 hours, 8 hours, 12 hours, 24 hours, and 48 hours after pentobarbital and hypothermia treatment. Initial ICP and maximum ICP prior to pentobarbital/hypothermia was significantly correlated with mortality (p=0.022 and p=0.026). Patients with an ICP>25 mmHg prior to pentobarbital/hypothermia initiation had an increased risk of mortality (p=0.0455). There was no statistically significant difference in mean ICP after 24 hours after pentobarbital/hypothermia protocol in survivors vs non-survivors. Increased time to reach 33°C was associated with increased mortality (r=0.47, p=0.047); with a 10.5-fold increase in mortality for >7 hours (OR 10.5, p=0.039). Conclusion Prolonged cooling time >7 hours was associated with a 10.5-fold increase in mortality and ICP>25 mmHg prior to initiation of pentobarbital and hypothermia is suggestive of a poor response to treatment. We recommend patients with severe TBI who develop RICH should first undergo a 12 x 15 cm decompressive hemicraniectomy because they have better survival and are more likely to have ICP <25 mmHg as the highest elevation of ICP if the ICP were to become and stay elevated again. Pentobarbital and hypothermia should be initiated if the ICP becomes elevated and sustained above 20 mmHg with a prior decompressive hemicraniectomy and refractory to other medical therapies. However, our data suggests that patients are unlikely to survive if there ICP does not decrease to less than 15mmHg at 8 and 12 hours after pentobarbital/hypothermia and remain less than 20 mmHg within first 48 hours.

Traumatic Brain Injury in the Pediatric Population

Traumatic brain injury (TBI) is a common injury among children. Most TBIs are mild and do not require hospitalization. However, whether or not the patients require acute hospitalization, TBIs may have long-lasting consequences. There is little research on the nutrient needs of these patients, and recommendations are frequently based on data from adults with TBI. It is clear that calorie and protein needs are elevated with acute TBI. However, calorie needs are also decreased by therapies such as sedation, chemical paralysis, and barbiturate coma. Long-term calorie needs may be lower for "comatose" patients. Enteral feeding is preferred and possible for patients with TBI, though gastric feeding may be problematic in some patients. In the acute phase, patients with TBI can also have dysregulation of fluid and electrolyte balance, which may require alterations in nutrition care. Dysphagia is common after moderately severe TBI and requires a multidisciplinary approach for treatment. Future opportunities for research on pediatric TBI are numerous and may include ongoing clarification of macronutrient needs, as well as investigation into the roles of specific nutrients such as zinc, antioxidants, and anti-inflammatory compounds.

Considerations in Fluids and Electrolytes After Traumatic Brain Injury

Appropriate fluid management of patients with traumatic brain injury (TBI) presents a challenge for many clinicians. Many of these patients may receive osmotic diuretics for the treatment of increased intracranial pressure or develop sodium disturbances, which act to alter fluid balance. However, establishment of fluid balance is extremely important for improving patient outcomes after neurologic injury. The use of hyperosmolar fluids, such as hypertonic saline, has gained significant interest because they are devoid of dehydrating properties and may have other beneficial properties for patients with TBI. Electrolyte derangements are also common after neurologic injury, with many having neurologic manifestations. In addition, the role of electrolyte abnormalities in the secondary neurologic injury cascade is being delineated and may offer a potential future therapeutic intervention.

Potentially preventable prehospital deaths from motor vehicle collisions

BACKGROUND

In 2011, about 30,000 people died in motor vehicle collisions (MVCs) in the United States. We sought to evaluate the causes of prehospital deaths related to MVCs and to assess whether these deaths were potentially preventable.

METHODS

Miami-Dade Medical Examiner records for 2011 were reviewed for all prehospital deaths of occupants of 4-wheeled motor vehicle collisions. Injuries were categorized by affected organ and anatomic location of the body. Cases were reviewed by a panel of 2 trauma surgeons to determine cause of death and whether the death was potentially preventable. Time to death and hospital arrival times were determined using the Fatality Analysis Reporting System (FARS) data from 2002 to 2012, which allowed comparison of our local data to national prevalence estimates.

RESULTS

Local data revealed that 39% of the 98 deaths reviewed were potentially preventable (PPD). Significantly more patients with PPD had neurotrauma as a cause of death compared to those with a nonpreventable death (NPD) (44.7% vs. 25.0%, P =.049). NPDs were significantly more likely to have combined neurotrauma and hemorrhage as cause of death compared to PPDs (45.0% vs. 10.5%, P <.001). NPDs were significantly more likely to have injuries to the chest, pelvis, or spine. NPDs also had significantly more injuries to the following organ systems: lung, cardiac, and vascular chest (all P <.05). In the nationally representative FARS data from 2002 to 2012, 30% of deaths occurred on scene and another 32% occurred within 1 h of injury. When comparing the 2011 FARS data for Miami-Dade to the remainder of the United States in that year, percentage of deaths when reported on scene (25 vs. 23%, respectively) and within 1 h of injury (35 vs. 32%, respectively) were similar.

CONCLUSIONS

Nationally, FARS data demonstrated that two thirds of all MVC deaths occurred within 1 h of injury. Over a third of prehospital MVC deaths were potentially preventable in our local sample. By examining injury patterns in PPDs, targeted intervention may be initiated.

Moderate hypothermia treatment in adult patients with severe traumatic brain injury: a meta-analysis

OBJECTIVES

To evaluate the effect of moderate hypothermia treatment (MHT) in severe traumatic brain injury (sTBI) compared to normothermia management.

METHODS

PubMed, Medline, Springer, Elsevier Science Direct, Cochrane Library and Google scholar were searched up to December 2012. Pooled risk ratios (RRs) and 95% confidence intervals (CIs) for the mortality and clinical neurological outcome of the adult patients with sTBI were collected and calculated in a fixed-effects model or a random-effects model. Summary effect estimates were stratified by study design and ethnicity. Egger's regression asymmetry tests were utilized for detecting the publication bias.

RESULTS

The overall estimates showed that MHT could reduce the mortality (hypothermia vs. normothermia, RR = 0.86, 95% CI = 0.73-1.01, p = 0.06) and unfavourable clinical neurological outcomes (RR = 1.21, 95% CI = 0.95-1.53, p = 0.12) for traumatic brain injured patients without statistical significance. Moreover, the further stratification sub-group analysis indicated that MHT presented a significant reduction (RR = 0.60, 95% CI = 0.44-0.83, p = 0.002) of mortality compared to the normothermia management in an Asian population. Surprisingly, American patients treated with moderate hypothermia showed an increasing mortality (RR = 1.07, 95% CI = 0.83-1.39, p = 0.61).

CONCLUSIONS

MHT may be effective in reducing death and unfavourable clinical neurological outcomes, but this finding is not statistically significant, except for decreasing the mortality in Asian patients.

Hyperosmolar therapy in severe traumatic brain injury: a survey of emergency physicians from a large Canadian province

INTRODUCTION

Worldwide, severe traumatic brain injury is a frequent pathology and is associated with high morbidity and mortality. Mannitol and hypertonic saline are therapeutic options for intracranial hypertension occurring in the acute phase of care. However, current practices of emergency physicians are unknown.

METHODS

We conducted a self-administered survey of emergency physicians in the province of Québec, Canada, to understand their attitudes surrounding the use of hyperosmolar solutions in patients with severe traumatic brain injury. Using information from a systematic review of hypertonic saline solutions and experts' opinion, we developed a questionnaire following a systematic approach (items generation and reduction). We tested the questionnaire for face and content validity, and test-retest reliability. Physicians were identified through the department head of each eligible level I and II trauma centers. We administered the survey using a web-based interface and planned email reminders.

RESULTS

We received 210 questionnaires out of 429 potentials respondents (response rate 49%). Most respondents worked in level II trauma centers (69%). Fifty-three percent (53%) of emergency physicians stated using hypertonic saline to treat severe traumatic brain injury. Most reported using hyperosmolar therapy in the presence of severe traumatic brain injury and unilateral reactive mydriasis, midline shift or cistern compression on brain computed tomography.

CONCLUSION

Hyperosmolar therapy is believed being broadly used by emergency physicians in Quebec following severe traumatic brain injury. Despite the absence of clinical practice guidelines promoting the use of hypertonic saline, a majority of them said to use these solutions in specific clinical situations.

The haemodynamic response to pre-hospital RSI in injured patients

BACKGROUND

Laryngoscopy and tracheal intubation provoke a marked sympathetic response, potentially harmful in patients with cerebral or cardiovascular pathology or haemorrhage. Standard pre-hospital rapid sequence induction of anaesthesia (RSI) does not incorporate agents that attenuate this response. It is not known if a clinically significant response occurs following pre-hospital RSI or what proportion of injured patients requiring the intervention are potentially at risk in this setting.

METHODS

We performed a retrospective analysis of 115 consecutive pre-hospital RSI's performed on trauma patients in a physician-led Helicopter Emergency Medical Service. Primary outcome was the acute haemodynamic response to the procedure. A clinically significant response was defined as a greater than 20% change from baseline recordings during laryngoscopy and intubation.

RESULTS

Laryngoscopy and intubation provoked a hypertensive response in 79% of cases. Almost one-in-ten patients experienced a greater than 100% increase in mean arterial pressure (MAP) and/or systolic blood pressure (SBP). The mean (95% CI) increase in SBP was 41(31-51) mmHg and MAP was 30(23-37) mmHg. Conditions leaving the patient vulnerable to secondary injury from a hypertensive response were common.

CONCLUSIONS

Laryngoscopy and tracheal intubation, following a standard pre-hospital RSI, commonly induced a clinically significant hypertensive response in the trauma patients studied. We believe that, although this technique is effective in securing the pre-hospital trauma airway, it is poor at attenuating adverse physiological effects that may be detrimental in this patient group.

Barbiturates use and its effects in patients with severe traumatic brain injury in five European countries

The guidelines for management of traumatic brain injury (TBI) recommend that high-dose barbiturate therapy may be considered to lower intracranial pressure (ICP) that is refractory to other therapeutic options. Lower doses of barbiturates may be used for sedation of patients with TBI, although there is no mention of this in the published guidelines. The goal of this study was to analyze the use of barbiturates in patients with severe TBI in the European centers where the International Neurotrauma Research Organization introduced guideline-based TBI management and to analyze the effects of barbiturates on ICP, use of vasopressors, and short- and long-term outcome of these patients. Data on 1172 patients with severe TBI were collected in 13 centers located in five European countries. Patients were categorized into three groups based on doses of barbiturates administered during treatment. Univariate and multivariate statistical methods were used to analyze the effects of barbiturates on the outcome of patients. Fewer than 20% of all patients with severe TBI were given barbiturates overall, and only 6% was given high doses. High-dose barbiturate treatment caused a decrease in ICP in 69% of patients but also caused hemodynamic instability leading to longer periods of mean arterial pressure <70 mm Hg despite increased use of high doses of vasopressors. The adjusted analysis showed no significant effect on outcome on any stage after injury.Thiopental and methohexital were equally effective. Low doses of thiopental and methohexital were used for sedation of patients without side effects. Phenobarbital was probably used for prophylaxis of post-traumatic seizures.

Head-up tilt and hyperventilation produce similar changes in cerebral oxygenation and blood volume: an observational comparison study using frequency-domain near-infrared spectroscopy

PURPOSE

During anesthesia, maneuvers which cause the least disturbance of cerebral oxygenation with the greatest decrease in intracranial pressure would be most beneficial to patients with intracranial hypertension. Both head-up tilt (HUT) and hyperventilation are used to decrease brain bulk, and both may be associated with decreases in cerebral oxygenation. In this observational study, our null hypothesis was that the impact of HUT and hyperventilation on cerebral tissue oxygen saturation (SctO2) and cerebral blood volume (CBV) are comparable.

METHODS

Surgical patients without neurological disease were anesthetized with propofol-remifentanil. Before the start of surgery, frequency-domain near-infrared spectroscopy was used to measure SctO2 and CBV at the supine position, at the 30° head-up and head-down positions, as well as during hypoventilation and hyperventilation.

RESULTS

Thirty-three patients were studied. Both HUT and hyperventilation induced small decreases in SctO2 [3.5 (2.6)%; P < 0.001 and 3.0 (1.8)%; P < 0.001, respectively] and in CBV [0.05 (0.07) mL x 100 g(-1); P < 0.001 and 0.06 (0.05) mL x 100 g(-1); P < 0.001, respectively]. There were no differences between HUT to 30° and hyperventilation to an end-tidal carbon dioxide (ETCO2) of 25 mmHg (from 45 mmHg) in both SctO2 (P = 0.3) and CBV (P = 0.4).

DISCUSSION

The small but statistically significant decreases in both SctO2 and CBV caused by HUT and hyperventilation are comparable. There was no correlation between the decreases in SctO2 and CBV and the decreases in blood pressure and cardiac output during head-up and head-down tilts. However, the decreases in both SctO2 and CBV correlate with the decreases in ETCO2 during ventilation adjustment.

Nonconvulsive seizures after traumatic brain injury are associated with hippocampal atrophy

OBJECTIVE

To determine if posttraumatic nonconvulsive electrographic seizures result in long-term brain atrophy.

METHODS

Prospective continuous EEG (cEEG) monitoring was done in 140 patients with moderate to severe traumatic brain injury (TBI) and in-depth study of 16 selected patients was done using serial volumetric MRI acutely and at 6 months after TBI. Fluorodeoxyglucose PET was done in the acute stage in 14/16 patients. These data were retrospectively analyzed after collection of data for 7 years.

RESULTS

cEEG detected seizures in 32/140 (23%) of the entire cohort. In the selected imaging subgroup, 6 patients with seizures were compared with a cohort of 10 age- and GCS-matched patients with TBI without seizures. In this subgroup, the seizures were repetitive and constituted status epilepticus in 4/6 patients. Patients with seizures had greater hippocampal atrophy as compared to those without seizures (21 +/- 9 vs 12 +/- 6%, p = 0.017). Hippocampi ipsilateral to the electrographic seizure focus demonstrated a greater degree of volumetric atrophy as compared with nonseizure hippocampi (28 +/- 5 vs 13 +/- 9%, p = 0.007). A single patient had an ictal PET scan which demonstrated increased hippocampal glucose uptake.

CONCLUSION

Acute posttraumatic nonconvulsive seizures occur frequently after TBI and, in a selected subgroup, appear to be associated with disproportionate long-term hippocampal atrophy. These data suggest anatomic damage is potentially elicited by nonconvulsive seizures in the acute postinjury setting.

Pentobarbital coma for refractory intra-cranial hypertension after severe traumatic brain injury: mortality predictions and one-year outcomes in 55 patients

OBJECTIVE

To identify predictors of mortality and long-term outcomes in survivors after pentobarbital coma (PBC) in patients failing current treatment standards for severe traumatic brain injuries (TBI). This is a retrospective cohort study of severe TBI patients receiving PBC at Level I Trauma Center and tertiary university hospital.

METHODS

Four thousand nine hundred thirty-four patients were admitted to the trauma intensive care unit with severe TBI (head Abbreviated Injury Scale >or= 3) between April 1998 and December 2004. Six hundred eleven received intracranial pressure (ICP) monitoring and 58 received PBC. Three patients underwent craniotomy for intracranial mass lesion and were excluded. The study group received standardized medical management for severe TBI including opiates, benzodiazepines, elevation of the head of bed, avoidance of hypotension and hypercapnia and hyperosmolar therapy (HOsmRx). In addition, 31 of 55 patients (56%) underwent placement of intraventricular catheters for cerebrospinal fluid drainage. If routine medical management and cerebrospinal fluid diversion failed to control ICP, then the patient was determined to have refractory intracranial hypertension (RICH) and PBC treatment was initiated. PBC was performed with pentobarbital infusion with continuous electroencephalogram monitoring to ensure adequate burst suppression. The measurements include serum sodium (Na) and osmolality (Osm) were assessed as indicators for initiation of PBC and to estimate the 50% mortality cut-points when controlling for ICP. Follow-up functional outcomes were assessed using the Glasgow Outcome Scale and stratified according to admission Glasgow Coma Scale score and Marshall computed tomography classification. Of the 55 PBC patients, 22 (40%) survived at discharge. 19 of 22 had long-term follow-up (1 year or more) available. Of these, 13 (68%) were normal or functionally independent (Glasgow Outcome Scale score 4 or 5). Serum Na and Osm were associated with death (p < 0.05) when controlling for ICP. The 50% mortality cut-points were Na of 160 mEq/L and Osm of 330 mOsm/kg H2O. Median minimum cerebral perfusion pressure after PBC was 42 mm Hg in survivors and 34 mm Hg in nonsurvivors (p = 0.013).

CONCLUSIONS

In patients with severe TBI and RICH, survival at discharge of 40% with good functional outcomes in 68% of survivors at 1 year or more can be achieved with PBC after failure of HOsmRx. Based on 50% mortality cut-points, analysis suggests the limits of HOsmRx to be Na of 160 mEq/L and Osm of 330 mOsm/Kg H2O. Maintenance of higher cerebral perfusion pressure after PBC is associated with survival. PBC treatment of RIH may be even more important when other treatments of RIH, such as decompressive craniectomy, are not available.

Contemporary pharmacologic issues in the management of traumatic brain injury

Traumatic brain injury (TBI) is a major cause of death and disability in the United States. While there are no pharmacotherapeutic options currently available for attenuating the neurologic injury cascade after TBI, numerous pharmacologic issues are encountered in these critically ill patients. Adequate fluid resuscitation, reversal of coagulopathy, maintenance of cerebral perfusion, and treatment of intracranial hypertension are common interventions early in the treatment of TBI. Other deleterious complications such as venous thromboembolism, extremes in glucose concentrations, and stress-related mucosal disease should be anticipated and avoided. Early provision of nutrition and prevention of drug or alcohol withdrawal are also cornerstones of routine care in TBI patients. Prevention of infections and seizures may also be helpful. Clinicians caring for TBI patients should be familiar with the pharmacologic issues typical of this vulnerable population in order to develop optimal strategies of care to anticipate and prevent common complications.

Hypertonic saline and its effect on intracranial pressure, cerebral perfusion pressure, and brain tissue oxygen

OBJECTIVE

Hypertonic saline is emerging as a potentially effective single osmotic agent for control of acute elevations in intracranial pressure (ICP) caused by severe traumatic brain injury. This study examines its effect on ICP, cerebral perfusion pressure (CPP), and brain tissue oxygen tension (PbtO2).

METHODS

Twenty-five consecutive patients with severe traumatic brain injury who were treated with 23.4% NaCl for elevated ICP were evaluated. Bolt catheter probes were placed in the noninjured hemisphere, and hourly ICP, mean arterial pressure, CPP, and PbtO2 values were recorded. Thirty milliliters of 23.4% NaCl was infused over 15 minutes for intracranial hypertension, defined as ICP greater than 20 mm Hg. Twenty-one male patients and 4 female patients aged 16 to 64 years were included. The mean presenting Glasgow Coma Scale score was 5.7.

RESULTS

Mean pretreatment values included an ICP level of 25.9 mm Hg and a PbtO2 value of 32 mm Hg. The posttreatment ICP level was decreased by a mean of 8.3 mm Hg (P < 0.0001), and there was an improvement in PbtO2 of 3.1 mm Hg (P < 0.01). ICP of more than 31 mm Hg decreased by 14.2 mm Hg. Pretreatment CPP values of less than 70 mm Hg increased by a mean of 6 mm Hg (P < 0.0001). No complications occurred from this treatment, with the exception of electrolyte and chemistry abnormalities. At 6 months postinjury, the mortality rate was 28%, with 48% of patients achieving a favorable outcome by the dichotomized Glasgow Outcome Scale.

CONCLUSION

Hypertonic saline as a single osmotic agent decreased ICP while improving CPP and PbtO2 in patients with severe traumatic brain injury. Patients with higher baseline ICP and lower CPP levels responded to hypertonic saline more significantly.

Rapid sequence airway vs rapid sequence intubation in a simulated trauma airway by flight crew

BACKGROUND

Rapid sequence airway (RSA) utilizes rapid sequence intubation (RSI) pharmacology followed by the placement of an extraglottic airway without direct laryngoscopy.

STUDY OBJECTIVE

To evaluate the difference in time to airway placement and lowest oxygen saturations in a simulated trauma patient using RSI or RSA with a Laryngeal Mask Airway-Supreme (LMAS).

METHODS

This randomized, prospective, non-blinded, IRB-approved observational study used a SimMan human simulator in an ambulance. FC were randomly assigned to initially manage the patient with RSI or RSA. They then completed the same scenario with the other modality to serve as their own control. Trained assistants performed directed tasks. SimMan had an initial grade III view and desaturated along a standardized curve until intubation, LMAS, or bag-valve-mask ventilation (BVMV) was initiated. When BVMV was used, oxygen saturation increased along a standardized curve. The simulator's airway converted to a grade II view after the first attempt if difficult airway maneuvers were applied. Time, oxygen saturation, number of attempts and back-up airway placement were recorded.

RESULTS

Nineteen FC completed both paired modalities. Paired T-test was used for statistical analysis. Average time to secure the airway was 145 s shorter in the RSA group (95% CI: 100.4-189.7). Lowest oxygen saturation was 4.8% higher (95% CI: 2.8-6.8) in the RSA group. During RSI, FC placed a back-up airway 47% of the time.

CONCLUSION

In a simulated moderately difficult trauma airway managed by FC, RSA results in a significantly shorter time to secure the airway and less hypoxemia compared to RSI.

Traumatic brain injury is associated with the development of deep vein thrombosis independent of pharmacological prophylaxis

INTRODUCTION

Deep venous thrombosis (DVT) is common among trauma patients. If left untreated it may result in lethal pulmonary thromboembolism. Previous studies have suggested that intracranial hemorrhage serves as an independent risk factor for the development of DVT. These studies were not able to exclude anticoagulation therapy as a confounding variable in their analysis. Our objective was to determine the association of traumatic brain injury (TBI) to the formation of DVT irrespective of the use of anticoagulation therapy.

METHODS

All patients admitted to an academic level I Trauma Center between 2000 and 2007 with blunt or penetrating injuries were selected for inclusion in this study. Patients who died or who were discharged within 24 hours of admission were excluded in the analysis. TBI was defined as any intraparenchymal hemorrhage or extra-axial intracranial bleeding identified on radiographic imaging or both. Anticoagulation therapy was defined as the uninterrupted use of either subcutaneous lovenox or heparin. Risk ratios and 95% confidence intervals compared the risk of DVT among patients with and without TBI according to the initiation of anticoagulation therapy (no therapy, <24 hours, 24-48 hours, and >48 hours) adjusted for age, gender, race, injury severity, mechanism of injury, spinal injury, and lower extremity fracture.

RESULTS

Irrespective of the time of initiation of pharmacologic prophylaxis, TBI is independently associated with the formation of DVT. A threefold to fourfold increased risk of DVT formation is consistent across all prophylaxis groups among patients with TBI.

CONCLUSION

The incidence of DVT among injured patients with TBI is significantly higher than those patients without head injury independent of anticoagulation therapy. Rigorous surveillance to detect DVT among trauma patients with TBI should be undertaken and where appropriate alternate means for pulmonary thromboembolism prevention used.

Pathophysiology of traumatic brain injury

Traumatic brain injury is a major source of death and disability worldwide. Significant success has been achieved in improving short-term outcomes in severe traumatic brain injury victims; however, there are still great limitations in our ability to return severe traumatic brain injury victims to high levels of functioning. Primary brain injury, due to initial injury forces, causes tissue distortion and destruction in the early postinjury period. Clinical outcomes depend in large part on mediating the bimolecular and cellular changes that occur after the initial injury. These secondary injuries from traumatic brain injury lead to alterations in cell function and propagation of injury through processes such as depolarization, excitotoxicity, disruption of calcium homeostasis, free-radical generation, blood-brain barrier disruption, ischemic injury, edema formation, and intracranial hypertension. The best hope for improving outcome in traumatic brain injury patients is a better understanding of these processes and the development of therapies that can limit secondary brain injury.

Prehospital management of traumatic brain injury

The aim of this study was to review the current protocols of prehospital practice and their impact on outcome in the management of traumatic brain injury. A literature review of the National Library of Medicine encompassing the years 1980 to May 2008 was performed. The primary impact of a head injury sets in motion a cascade of secondary events that can worsen neurological injury and outcome. The goals of care during prehospital triage, stabilization, and transport are to recognize life-threatening raised intracranial pressure and to circumvent cerebral herniation. In that process, prevention of secondary injury and secondary insults is a major determinant of both short- and longterm outcome. Management of brain oxygenation, blood pressure, cerebral perfusion pressure, and raised intracranial pressure in the prehospital setting are discussed. Patient outcomes are dependent upon an organized trauma response system. Dispatch and transport timing, field stabilization, modes of transport, and destination levels of care are addressed. In addition, special considerations for mass casualty and disaster planning are outlined and recommendations are made regarding early response efforts and the ethical impact of aggressive prehospital resuscitation. The most sophisticated of emergency, operative, or intensive care units cannot reverse damage that has been set in motion by suboptimal protocols of triage and resuscitation, either at the injury scene or en route to the hospital. The quality of prehospital care is a major determinant of long-term outcome for patients with traumatic brain injury.

Beta-2 receptor antagonists for traumatic brain injury: a systematic review of controlled trials in animal models

A systematic review and meta-analysis of controlled trials was undertaken to assess the effects of beta-2 receptor antagonists in animal models of traumatic brain injury (TBI). Database and reference list searches were performed to identify eligible studies. Outcome data were extracted on functional status, as measured by the grip test or neurological severity score (NSS), and cerebral edema, as measured by brain water content (BWC). Data were pooled using the random-effects model. Seventeen controlled trials involving 817 animals were identified. Overall methodological quality was poor. Results from the grip test suggest that the treatment group maintained grip for a longer period than the control group; pooled weighted mean difference (WMD) = 8.28 (95% CI 5.78-10.78). The treatment group was found to have a lower NSS (i.e., better neurological function); pooled WMD =-3.28 (95% CI -4.72 to -1.85). Analysis of the cerebral edema data showed that the treatment group had a lower BWC than the control; pooled WMD =-0.42 (95% CI -0.59 to -0.26). There was evidence of statistical heterogeneity between comparisons for all outcomes. Evidence for small study effects was found for the grip test and BWC outcomes. The evidence from animal models of TBI suggests that beta-2 receptor antagonists can improve functional outcome and lessen cerebral edema. However, the poor methodological quality of the included studies and presence of small study effects may have influenced these findings.

Does ICP monitoring make a difference in neurocritical care?

Raised intracranial pressure and low cerebral perfusion pressure are associated with ischaemia and poor outcome after brain injury. Therefore, many management protocols target these variables. However, there are no randomized controlled trials that have demonstrated the effectiveness of intracranial pressure-guided care in severely head-injured patients. Observational studies of such therapy have yielded inconsistent results, ranging from decreased mortality to no effect or increased morbidity or mortality. A recent cohort study supports the notion that the possible benefits of intracranial pressure monitoring after traumatic brain injury are small - if present - and would exceed a number needed for the treatment of 16. Furthermore, intracranial pressure monitoring and aggressive management of intracranial pressure and cerebral perfusion pressure have been associated with increased lengths of stay in the neurocritical care unit, conceivable costs and possibly an increased rate of complications. Against this background, there is sufficient clinical equipoise to warrant an adequately powered randomized controlled trial to compare intracranial pressure-guided care with supportive critical care without intracranial pressure monitoring in patients with severe traumatic brain injury. However, the realization of such a trial is likely to be problematic for a number of reasons, not least of which the firmly held biases of many clinicians.

Design and validation of a critical pathway for hospital management of patients with severe traumatic brain injury

BACKGROUND

Critical pathways for the management of patients with severe traumatic brain injury (STBI) may contribute to reducing the incidence of hospital complications, length of hospitalization stay, and cost of care. Such pathways have previously been developed for departments with significant resource availability. In Mexico, STBI is the most important cause of complications and length of stay in neurotrauma services at public hospitals. Although current treatment is designed basically in accordance with the Brain Trauma Foundation guidelines, shortfalls in the availability of local resources make it difficult to comply with these standards, and no critical pathway is available that accords with the resources of public hospitals. The purpose of the present study was to design and to validate a critical pathway for managing STBI patients that would be suitable for implementation in neurotrauma departments of middle-income level countries.

METHODS

The study comprised two phases: design (through literature review and design plan) and validation (content, construct, and appearance) of the critical pathway.

RESULTS

The validated critical pathway for managing STBI patients entails four sequential subprocesses summarizing the hospital's care procedures, and includes three components: (1) nodes and criteria (in some cases, indicators are also included); (2) health team members in charge of the patient; (3) maximum estimated time for compliance with recommendations.

CONCLUSIONS

This validated critical pathway is based on the current scientific evidence and accords with the availability of resources of middle-income countries.

Traumatic brain injury: an integrated clinical case presentation and literature review part II: the continuum of care

The following paper continues the presentation of a case scenario outlining the assessment, interventions and outcome of a person who sustained multiple trauma with a focus on traumatic brain injury (TBI). Part I explored assessment and initial management of the patient from pre-hospital care through to the emergency department and operating theatre. Part II describes the intensive care period as an integral component of the continuum of care. Key issues in the case are presented sequentially with relevant theory integrated and applied to the clinical case throughout the discussion with a focus on the complex physiological, psychological, and spiritual needs of the patient and their family.

Beta-2 receptor antagonists for acute traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Cerebral oedema, the accumulation of fluid within the brain, is believed to be an important contributor to the secondary brain damage that occurs following injury. The release of kinins is thought to be an important factor in the development of cerebral vasogenic oedema and the use of beta-2 receptor antagonists, which prevent the release of these kinins, have been proposed as a potential therapeutic intervention.

OBJECTIVES

The objective was to assess the safety and effectiveness of beta-2 receptor antagonists for TBI.

SEARCH STRATEGY

We searched the Cochrane Injuries Group's specialised register, CENTRAL, MEDLINE, EMBASE, National Research Register, LILACs, Zetoc, Web of Knowledge and Current Controlled Trials. We also searched the internet and checked the reference lists of relevant papers to identify any further studies. The searches were conducted in March 2007.

SELECTION CRITERIA

Randomised controlled trials of beta-2 receptor antagonists versus placebo for TBI.

DATA COLLECTION AND ANALYSIS

Two authors independently screened search results and assessed the full texts of potentially relevant studies for inclusion. Data were extracted and methodological quality was examined. Relative risks (RR) and 95% confidence intervals (CIs) were calculated and data were pooled using a fixed effect model.

MAIN RESULTS

Three studies were included, involving 178 participants. All three studies reported the effects of beta-2 receptor antagonists on mortality. The pooled RR for mortality was 0.63 (95% CI 0.36 to 1.10). Two studies measured disability, the RR of death or severe disability with beta-2 receptor antagonists was 0.81 (95% CI 0.59 to 1.09). Two studies measured the effect on intracranial pressure (ICP), although in only one did this finding reach statistical significance. There was no evidence for the presence of heterogeneity.

AUTHORS' CONCLUSIONS

There is no reliable evidence that beta-2 receptor antagonists are effective in reducing mortality or disability after TBI. Further well conducted randomised controlled trials are required.

Effects of Fentanyl and S(+)-ketamine on Cerebral Hemodynamics, Gastrointestinal Motility, and Need of Vasopressors in Patients With Intracranial Pathologies

In neurosurgical patients, opioids are administered to prevent secondary cerebral damage. Complications often related to the administration of opioids are a decrease in blood pressure affording the use of vasopressors and intestinal atonia. One alternative approach to opioids is the application of S(+)-ketamine. However, owing to a suspected elevation of intracranial pressure (ICP), the administration of S(+)-ketamine has questioned for a long time. The aim of the present study was to evaluate ICP, gastrointestinal motility, and catecholamine consumption in neurosurgical patients undergoing 2 different protocols of anesthesia using fentanyl or S(+)-ketamine. Twenty-four patients sustaining traumatic brain injury or aneurysmal subarachnoid hemorrhage received methohexitone plus either fentanyl or S(+)-ketamine to establish a comparable level of sedation. To reach an adequate cerebral perfusion pressure (CPP), the norepinephrine dosage was adapted successively. Enteral nutrition and gastrointestinal stimulation were started directly after admission on the critical care unit. ICP, CPP, and norepinephrine dosage were recorded over 5 days and also the time intervals to full enteral nutrition and first defecation. There was no difference regarding ICP, CPP, and the time period until full enteral nutrition or first defecation between both groups. Patients who underwent analgesia with S(+)-ketamine showed a trend to a lower demand of norepinephrine compared with the fentanyl group. Our results indicate that S(+)-ketamine does not increase ICP and that its use in neurosurgical patients should not be discouraged on the basis of ICP-related concerns.

Effects of therapeutic mild hypothermia on patients with severe traumatic brain injury after craniotomy

PURPOSE

We investigated the effects of therapeutic mild hypothermia on patients with severe traumatic brain injury after craniotomy (TBI).

METHODS

Eighty patients with severe TBI after unilateral craniotomy were randomized into a therapeutic hypothermia group with the brain temperature maintained at 33 degrees C to 35 degrees C for 4 days, and a normothermia control group in the intensive care unit. Vital signs, intracranial pressure, serum superoxide dismutase level, Glasgow Outcome Scale scores, and complications were prospectively analyzed.

RESULTS

The mean intracranial pressure values of the therapeutic hypothermia group at 24, 48, and 72 hours after injury were much lower than those of the control group (23.49 +/- 2.38, 24.68 +/- 1.71, and 22.51 +/- 2.44 vs 25.87 +/- 2.18, 25.90 +/- 1.86, and 24.57 +/- 3.95 mm Hg; P = .000, .000, and .003, respectively). The mean serum superoxide dismutase levels of the therapeutic hypothermia group at days 3 and 7 were much higher than those of the control group at the same time point (533.0 +/- 103.4 and 600.5 +/- 82.9 vs 458.7 +/- 68.1 and 497.0 +/- 57.3 mug/L, respectively; P = .000). The percentage of favorable neurologic outcome 1 year after injury was 70.0% and 47.5%, respectively (P = .041). Complications, including pulmonary infections (57.5% in the therapeutic hypothermia group vs 32.5% in the control group; P = .025) were managed without severe sequelae.

CONCLUSIONS

Therapeutic mild hypothermia provides a promising way in the intensive care unit for patients with severe TBI after craniotomy.

Complications of emergency tracheal intubation: hemodynamic alterations--part I

Emergency airway management outside the elective operating room presents considerable risks to the patient and significant challenges to the practitioner. Complications and adverse consequences are commonplace, yet they have not received their justified discussion or scrutiny in the literature. This review will discuss potentially life-threatening complications partitioned into 2 broad categories: hemodynamic and airway. Part 1 will focus on alterations in the heart rate and blood pressure, new onset cardiac dysrhythmias and cardiac arrest. Part 2 will explore airway related consequences such as hypoxemia, esophageal intubation, multiple intubation attempts, and aspiration.

Use of Hypertonic 7.5% Sodium Chloride (NaCl) Solution in Patients with Traumatic Brain Injuries Trauma: Antibiotics in Open Fractures: Sedation Update: Time for a Change?

This feature examines the impact of pharmacologic interventions on the treatment of the critically ill patient — an area of health care that has become increasingly complex. Recent advances in drug therapy (including evolving and controversial data) for adult intensive-care-unit patients will be reviewed and assessed in terms of clinical, humanistic, and economic outcomes. Direct questions or comments to Sandra Kane-Gill, PharmD, MSc, at kanesl@upmc.edu .

Safety of rFVIIa in hemodynamically unstable polytrauma patients with traumatic brain injury: post hoc analysis of 30 patients from a prospective, randomized, placebo-controlled, double-blind clinical trial

BACKGROUND

Trauma is a leading cause of mortality and morbidity, with traumatic brain injury (TBI) and uncontrolled hemorrhage responsible for the majority of these deaths. Recombinant activated factor VIIa (rFVIIa) is being investigated as an adjunctive hemostatic treatment for bleeding refractory to conventional replacement therapy in trauma patients. TBI is a common component of polytrauma injuries. However, the combination of TBI with polytrauma injuries is associated with specific risk factors and treatment modalities somewhat different from those of polytrauma without TBI. Although rFVIIa treatment may offer added potential benefit for patients with combined TBI and polytrauma, its safety in this population has not yet been assessed. We conducted a post hoc sub analysis of patients with TBI and severe blunt polytrauma enrolled into a prospective, international, double-blind, randomized, placebo-controlled study.

METHODS

A post hoc analysis of study data was performed for 143 patients with severe blunt trauma enrolled in a prospective, randomized, placebo-controlled study, evaluating the safety and efficacy of intravenous rFVIIa (200 + 100 + 100 microg/kg) or placebo, to identify patients with a computed tomography (CT) diagnosis of TBI. The incidences of ventilator-free days, intensive care unit-free days, and thromboembolic, serious, and adverse events within the 30-day study period were assessed in this cohort.

RESULTS

Thirty polytrauma patients (placebo, n = 13; rFVIIa, n = 17) were identified as having TBI on CT. No significant differences in rates of mortality (placebo, n = 6, 46%, 90% confidence interval (CI): 22% to 71%; rFVIIa, n = 5, 29%, 90% CI: 12% to 56%; P = 0.19), in median numbers of intensive care unit-free days (placebo = 0, rFVIIa = 3; P = 0.26) or ventilator-free days (placebo = 0, rFVIIa = 10; P = 0.19), or in rates of thromboembolic adverse events (placebo, 15%, 90% CI: 3% to 51%; rFVIIa, 0%, 90% CI: 0% to 53%; P = 0.18) or serious adverse events (placebo, 92%, 90% CI: 68% to 98%; rFVIIa, 82%, 90% CI: 60% to 92%; P = 0.61) were observed between treatment groups.

CONCLUSION

The use of a total dose of 400 (200 + 100 + 100) microg/kg rFVIIa in this group of hemodynamically unstable polytrauma patients with TBI was not associated with an increased risk of mortality or with thromboembolic or adverse events.

Respiratory mechanics in brain-damaged patients

OBJECTIVE

To assess respiratory mechanics on the 1st and 5th days of mechanical ventilation in a cohort of brain-damaged patients on positive end-expiratory pressure (PEEP) of 8 cmH(2)O or zero PEEP (ZEEP).

DESIGN AND SETTING

Physiological study with randomized control trial design in a multidisciplinary intensive care unit of a university hospital.

PATIENTS AND MEASUREMENTS

Twenty-one consecutive mechanically ventilated patients with severe brain damage and no acute lung injury were randomly assigned to be ventilated with ZEEP (n = 10) or with 8 cmH(2)O of PEEP (n = 11). Respiratory mechanics and arterial blood gases were assessed on days 1 and day 5 of mechanical ventilation.

RESULTS

In the ZEEP group on day 1 static elastance and minimal resistance were above normal limits (18.9 +/- 3.8 cmH(2)O/l and 5.6 +/- 2.2 cmH(2)O/l per second, respectively); on day 5 static elastance and iso-CO(2) minimal resistance values were higher than on day 1 (21.2 +/- 4.1 cmH(2)O/l; 7.0 +/- 1.9 cmH(2)O/l per second, respectively). In the PEEP group these parameters did not change significantly. One of the ten patients on ZEEP developed acute lung injury. On day 5 there was a significant decrease in PaO(2)/FIO(2) in both groups.

CONCLUSIONS

On day 1 of mechanical ventilation patients with brain damage exhibit abnormal respiratory mechanics. After 5 days of mechanical ventilation on ZEEP static elastance and minimal resistance increased significantly, perhaps reflecting "low lung volume" injury. Both could be prevented by administration of moderate levels of PEEP.

Effects of selective brain cooling in patients with severe traumatic brain injury: a preliminary study

We prospectively investigated non-invasive selective brain cooling (SBC) in patients with severe traumatic brain injury. Sixty-six in-patients were randomized into three groups. In one group, brain temperature was maintained at 33 - 35 degrees C by cooling the head and neck (SBC); in a second group, mild systemic hypothermia (MSH; rectal temperature 33 - 35 degrees C) was produced with a cooling blanket; and a control group was not exposed to hypothermia. Natural rewarming began after 3 days. Mean intracranial pressure 24, 48 or 72 h after injury was significantly lower in the SBC group than in the control group. Mean serum superoxide dismutase levels on Days 3 and 7 after injury in the SBC and MSH groups were significantly higher than in the control group. The percentage of patients with a good neurological outcome 2 years after injury was 72.7%, 57.1% and 34.8% in the SBC, MSH and control groups, respectively. Complications were managed without severe sequelae. Non-invasive SBC was safe and effective.

Acute, transient hemorrhagic hypotension does not aggravate structural damage or neurologic motor deficits but delays the long-term cognitive recovery following mild to moderate traumatic brain injury

OBJECTIVES

Posttraumatic hypotension is believed to increase morbidity and mortality in traumatically brain-injured patients. Using a clinically relevant model of combined traumatic brain injury with superimposed hemorrhagic hypotension in rats, the present study evaluated whether a reduction in mean arterial blood pressure aggravates regional brain edema formation, regional cell death, and neurologic motor/cognitive deficits associated with traumatic brain injury.

DESIGN

Experimental prospective, randomized study in rodents.

SETTING

Experimental laboratory at a university hospital.

SUBJECTS

One hundred nineteen male Sprague-Dawley rats weighing 350-385 g.

INTERVENTIONS

Experimental traumatic brain injury of mild to moderate severity was induced using the lateral fluid percussion brain injury model in anesthetized rats (n = 89). Following traumatic brain injury, in surviving animals one group of animals was subjected to pressure-controlled hemorrhagic hypotension, maintaining the mean arterial blood pressure at 50-60 mm Hg for 30 mins (n = 47). The animals were subsequently either resuscitated with lactated Ringer's solution (three times shed blood volume, n = 18) or left uncompensated (n = 29). Other groups of animals included those with isolated traumatic brain injury (n = 34), those with isolated hemorrhagic hypotension (n = 8), and sham-injured control animals receiving anesthesia and surgery alone (n = 22).

MEASUREMENTS AND MAIN RESULTS

The withdrawal of 6-7 mL of arterial blood significantly reduced mean arterial blood pressure by 50% without decreasing arterial oxygen saturation or Pao2. Brain injury induced significant cerebral edema (p < .001) in vulnerable brain regions and cortical tissue loss (p < .01) compared with sham-injured animals. Neither regional brain edema formation at 24 hrs postinjury nor the extent of cortical tissue loss assessed at 7 days postinjury was significantly aggravated by superimposed hemorrhagic hypotension. Brain injury-induced neurologic deficits persisted up to 20 wks after injury and were also not aggravated by the hemorrhagic hypotension. Cognitive dysfunction persisted for up to 16 wks postinjury. The superimposition of hemorrhagic hypotension significantly delayed the time course of cognitive recovery.

CONCLUSIONS

A single, acute hypotensive event lasting 30 mins did not aggravate the short- and long-term structural and motor deficits but delayed the speed of recovery of cognitive function associated with experimental traumatic brain injury.