Phase II clinical trial of moderate hypothermia after severe traumatic brain injury in children

Brain tissue oxygen monitoring after severe traumatic brain injury in children: relationship to outcome and association with other clinical parameters

OBJECT

Minimizing secondary brain injuries after traumatic brain injury (TBI) in children is critical to maximizing neurological outcome. Brain tissue oxygenation monitoring (as measured by interstitial partial pressure of O2 [PbO2]) is a new tool that may aid in guiding therapies, yet experience in children is limited. This study aims to describe the authors' experience of PbO2 monitoring after TBI. It was hypothesized that PbO2 thresholds could be established that were associated with favorable neurological outcome, and it was determined whether any relationships between PbO2 and other important clinical variables existed.

METHODS

Forty-six children with severe TBI (Glasgow coma scale score ≤ 8 after resuscitation) who underwent PbO2 and brain temperature monitoring between September 2004 and June 2008 were studied. All patients received standard neurocritical care, and 24 were concurrently enrolled in a trial of therapeutic early hypothermia (n = 12/group). The PbO2 was measured in the uninjured frontal cortex. Hourly recordings and calculated daily means of various variables including PbO2, intracranial pressure (ICP), cerebral perfusion pressure (CPP), mean arterial blood pressure, partial pressure of arterial O2, and fraction of inspired O2 were compared using several statistical approaches. Glasgow outcome scale scores were determined at 6 months after injury.

RESULTS

The mean patient age was 9.4 years (range 0.1-16.5 years; 13 girls) and 8554 hours of monitoring were analyzed (PbO2 range 0.0-97.2 mm Hg). A PbO2 of 30 mm Hg was associated with the highest sensitivity/specificity for favorable neurological outcome at 6 months after TBI, yet CPP was the only factor that was independently associated with favorable outcome. Surprisingly, instances of preserved PbO2 with altered ICP and CPP were observed in some children with unfavorable outcomes.

CONCLUSIONS

Monitoring of PbO2 demonstrated complex interactions with clinical variables reflecting intracranial dynamics using this protocol. A higher threshold than reported in studies in adults was suggested as a potential therapeutic target, but this threshold was not associated with improved outcomes. Additional studies to assess the utility of PbO2 monitoring after TBI in children are needed.

The study of systemic general circulation disturbance during the initiation of therapeutic hypothermia: Pit fall of hypothermia

Aims:

Neurointensive care has reduced the mortality and improved the outcome of patients for severe brain damage, over recent decades, and made it possible to perform this therapy in safety. However, we have to understand the complications of this therapy well. The purpose of our study was to determine the systemic circulation disturbance during the initiation of therapeutic hypothermia by using this continuous neurointensive monitoring system.

Materials and Methods:

Ten severe brain damage patients treated with hypothermia were enrolled. All patients had Glasgow Coma Scale (GCS) less than or equal to 8, on admission.

Results:

We verified that heart rate, cardiac output, and oxygen delivery index (DO2I) decreased with decreasing core temperature. We recognized that depressed cardiac index (CI) was attributed to bradycardia, dehydration, and increased systemic vascular resistance index (SVRI) upon initiation of hypothermia.

Conclusion:

Although the hypothermia has a therapeutic role in severe brain damage patients, we have to carry out this therapy while maintaining their cardiac output using multimodality monitoring devices during hypothermia period.

Hospital care of childhood traumatic brain injury in the United States, 1997-2009: a neurosurgical perspective

OBJECT

The goal in this paper was to study hospital care for childhood traumatic brain injury (TBI) in a nationwide population base.

METHODS

Data were acquired from the Kids' Inpatient Database (KID) for the years 1997, 2000, 2003, 2006, and 2009. Admission for TBI was defined by any ICD-9-CM diagnostic code for TBI. Admission for severe TBI was defined by a principal diagnostic code for TBI and a procedural code for mechanical ventilation; admissions ending in discharge home alive in less than 4 days were excluded.

RESULTS

Estimated raw and population-based rates of admission for all TBI, for severe TBI, for death from severe TBI, and for major and minor neurosurgical procedures fell steadily during the study period. Median hospital charges for severe TBI rose steadily, even after adjustment for inflation, but estimated nationwide hospital charges were stable. Among 14,932 actual admissions for severe TBI captured in the KID, case mortality was stable through the study period, at 23.9%. In a multivariate analysis, commercial insurance (OR 0.86, CI 0.77-0.95; p = 0.004) and white race (OR 0.78, CI 0.70-0.87; p < 0.0005) were associated with lower mortality rates, but there was no association between these factors and commitment of resources, as measured by hospital charges or rates of major procedures. Increasing median income of home ZIP code was associated with higher hospital charges and higher rates of major and minor procedures. Only 46.8% of admissions for severe TBI were coded for a neurosurgical procedure of any kind. Fewer admissions were coded for minor neurosurgical procedures than anticipated, and the state-by-state variance in rates of minor procedures was twice as great as for major procedures. Possible explanations for the "missing ICP monitors" are discussed.

CONCLUSIONS

Childhood brain trauma is a shrinking sector of neurosurgical hospital practice. Racial and economic disparities in mortality rates were confirmed in this study, but they were not explained by available metrics of resource commitment. Vigilance is required to continue to supply neurosurgical expertise to the multidisciplinary care process.

Perioperative management of the pediatric patient with traumatic brain injury

TBI and its sequelae remain a major healthcare issue throughout the world. With an improved understanding of the pathophysiology of TBI, refinements of monitoring technology, and ongoing research to determine optimal care, the prognosis of TBI continues to improve. In 2003, the Society of Critical Care Medicine published guidelines for the acute management of severe TBI in infants, children, and adolescents. As pediatric anesthesiologists are frequently involved in the perioperative management of such patients including their stabilization in the emergency department, familiarity with these guidelines is necessary to limit preventable secondary damage related to physiologic disturbances. This manuscript reviews the current evidence-based medicine regarding the care of pediatric patients with TBI as it relates to the perioperative care of such patients. The issues reviewed include those related to initial stabilization, airway management, intra-operative mechanical ventilation, hemodynamic support, administration of blood and blood products, positioning, and choice of anesthetic technique. The literature is reviewed regarding fluid management, glucose control, hyperosmolar therapy, therapeutic hypothermia, and corticosteroids. Whenever possible, management recommendations are provided.

Translational barriers and opportunities for emergency preservation and resuscitation in severe injuries

BACKGROUND

Hypothermia is commonly used for organ and tissue preservation in multiple clinical settings, but its role in the management of injured patients remains controversial. There is no doubt that temperature modulation is a powerful tool, and hypothermia has been shown to protect cells during ischaemia and reperfusion, decrease organ damage and improve survival. Yet hypothermia is a double-edged sword: unless carefully managed, its induction can be associated with a number of complications.

METHODS

A literature review was performed to include important papers that address the impact of hypothermia on key biological processes, and explore the potential therapeutic role of hypothermia in trauma/haemorrhage models.

RESULTS

No clinical studies have been conducted to test the therapeutic benefits of hypothermia in injured patients. However, numerous well designed animal studies support this concept. Despite excellent preclinical data, there are several potential barriers to translating hypothermia into clinical practice.

CONCLUSION

Therapeutic hypothermia is a promising life-saving strategy. Appropriate patient selection requires a thorough understanding of how temperature modulation affects various biological mechanisms.

Cerebrospinal fluid levels of high-mobility group box 1 and cytochrome C predict outcome after pediatric traumatic brain injury

High-mobility group box 1 (HMGB1) is a ubiquitous nuclear protein that is passively released from damaged and necrotic cells, and actively released from immune cells. In contrast, cytochrome c is released from mitochondria in apoptotic cells, and is considered a reliable biomarker of apoptosis. Thus, HMGB1 and cytochrome c may in part reflect the degree of necrosis and apoptosis present after traumatic brain injury (TBI), where both are felt to contribute to cell death and neurological morbidity. Ventricular cerebrospinal fluid (CSF) was obtained from children admitted to the intensive care unit (ICU) after TBI (n=37). CSF levels of HMGB1 and cytochrome c were determined at four time intervals (0-24 h, 25-48 h, 49-72 h, and>72 h after injury) using enzyme-linked immunosorbent assay (ELISA). Lumbar CSF from children without TBI served as controls (n=12). CSF HMGB1 levels were: control=1.78±0.29, 0-24 h=5.73±1.45, 25-48 h=5.16±1.73, 49-72 h=4.13±0.75,>72 h=3.80±0.90 ng/mL (mean±SEM). Peak HMGB1 levels were inversely and independently associated with favorable Glasgow Outcome Scale (GOS) scores at 6 mo (0.49 [0.24-0.97]; OR [5-95% CI]). CSF cytochrome c levels were: control=0.37±0.10, 0-24 h=0.69±0.15, 25-48 h=0.82±0.48, 49-72 h=1.52±1.08,>72 h=1.38±1.02 ng/mL (mean±SEM). Peak cytochrome c levels were independently associated with abusive head trauma (AHT; 24.29 [1.77-334.03]) and inversely and independently associated with favorable GOS scores (0.42 [0.18-0.99]). In conclusion, increased CSF levels of HMGB1 and cytochrome c were associated with poor outcome after TBI in infants and children. These data are also consistent with the designation of HMGB1 as a "danger signal." Distinctly increased CSF cytochrome c levels in infants and children with AHT and poor outcome suggests that apoptosis may play an important role in this unique patient population.

Therapeutic hypothermia for acute neurological injuries

Therapeutic hypothermia (TH) is the intentional reduction of core body temperature to 32°C to 35°C, and is increasingly applied by intensivists for a variety of acute neurological injuries to achieve neuroprotection and reduction of elevated intracranial pressure. TH improves outcomes in comatose patients after a cardiac arrest with a shockable rhythm, but other off-label applications exist and are likely to increase in the future. This comprehensive review summarizes the physiology and cellular mechanism of action of TH, as well as different means of TH induction and maintenance with potential side effects. Indications of TH are critically reviewed by disease entity, as reported in the most recent literature, and evidence-based recommendations are provided.

Relationship between hyperglycemia and outcome in children with severe traumatic brain injury

OBJECTIVE

To determine the relationship between hyperglycemia and outcome in infants and children after severe traumatic brain injury.

DESIGN

Retrospective review of a prospectively collected Pediatric Neurotrauma Registry.

SETTING AND PATIENTS

Children admitted after severe traumatic brain injury (postresuscitation Glasgow Coma Scale ≤ 8) were studied (1999-2004). A subset of children (n = 28) were concurrently enrolled in a randomized, controlled clinical trial of early hypothermia for neuroprotection.

INTERVENTIONS

Demographic data, serum glucose concentrations, and outcome assessments were collected.

METHODS AND MAIN RESULTS

Children (n = 57) were treated with a standard traumatic brain injury protocol. Exogenous glucose was withheld for 48 hrs after injury unless hypoglycemia was observed (blood glucose <70 mg/dL). Early (first 48 hrs) and Late (49-168 hrs) time periods were defined and mean blood glucose concentrations were calculated. Additionally, children were categorized based on peak blood glucose concentrations during each time period (normal, blood glucose <150 mg/dL; mild hyperglycemia, blood glucose ≤ 200 mg/dL; severe hyperglycemia, blood glucose >200 mg/dL). In the Late period, an association between elevated mean serum glucose concentration and outcome was observed (133.5 ± 5.6 mg/dL in the unfavorable group vs. 115.4 ± 4.1 mg/dL in favorable group, p = .02). This association continued to be significant after correcting for injury severity, age, and exposure to insulin (p = .03). Similarly, in the Late period, children within the severe hyperglycemia group had decreased incidence of good outcome compared to children within the other glycemic groups (% good outcome: normal, 61.9%; mild hyperglycemia, 73.7%; severe hyperglycemia, 33.3%; p = .05). However, when adjusted for exposure to insulin, this relationship was no longer statistically significant.

CONCLUSIONS

In children with severe traumatic brain injury, hyperglycemia beyond the initial 48 hrs is associated with poor outcome. This relationship was observed in both our analysis of mean blood glucose concentrations as well as among the patients with episodic severe hyperglycemia. This observation suggests a relationship between hyperglycemia and outcome from traumatic brain injury. However, only a prospective study can answer the important question of whether manipulating serum glucose concentration can improve outcome after traumatic brain injury in children.

Fever control and application of hypothermia using intravenous cold saline

OBJECTIVES

To describe the use and feasibility of cold saline to decrease body temperature in pediatric neurocritical care.

DESIGN

Retrospective chart review.

SETTING

Pediatric tertiary care university hospital.

PATIENTS

Children between 1 wk and 17 yrs of age admitted to the pediatric intensive care unit with acute brain injury and having received intravenous cold saline between June and August 2009.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Eighteen subjects accounted for 20 infusions with mean infusion volume 18 ± 10 mL/kg. Eight subjects had traumatic brain injury, two had intracranial hemorrhage, six had cardiac arrest, and one each had ischemic stroke and status epilepticus. The mean age was 9.5 ± 4.8 yrs. Temperature decreased from 38.7 ± 1.1°C to 37.7 ± 1.2°C and from 37.0 ± 2.0°C to 35.3 ± 1.6°C 1 hr after infusion for fever (n = 14; p < .05) or hypothermia induction (n = 6; p = .05), respectively. Cold saline was not bloused but rather infused over 10-15 mins. Mean arterial blood pressure and oxygenation parameters (PaO2/FIO2 ratio, mean airway pressure) were unchanged, but heart rate decreased in those with hypothermia (121 ± 4 beats per minute vs. 109 ± 12 beats per minute; p < .05). Serum sodium concentration and international normalized ratio were significantly increased after cold saline infusion. There were no differences between preinfusion and postinfusion serum glucose and hematocrit, or between cerebral perfusion pressure and intracranial pressure in traumatic brain injury patients.

CONCLUSIONS

Cold saline was an effective method of reducing temperature in children with acute brain injury. This approach can be considered to treat fever or to induce hypothermia. A prospective study comparing safety and efficacy vs. other cooling measures should be considered.

Therapeutic hypothermia in stroke and traumatic brain injury

Therapeutic hypothermia (TH) is considered to improve survival with favorable neurological outcome in the case of global cerebral ischemia after cardiac arrest and perinatal asphyxia. The efficacy of hypothermia in acute ischemic stroke (AIS) and traumatic brain injury (TBI), however, is not well studied. Induction of TH typically requires a multimodal approach, including the use of both pharmacological agents and physical techniques. To date, clinical outcomes for patients with either AIS or TBI who received TH have yielded conflicting results; thus, no adequate therapeutic consensus has been reached. Nevertheless, it seems that by determining optimal TH parameters and also appropriate applications, cooling therapy still has the potential to become a valuable neuroprotective intervention. Among the various methods for hypothermia induction, intravascular cooling (IVC) may have the most promise in the awake patient in terms of clinical outcomes. Currently, the IVC method has the capability of more rapid target temperature attainment and more precise control of temperature. However, this technique requires expertise in endovascular surgery that can preclude its application in the field and/or in most emergency settings. It is very likely that combining neuroprotective strategies will yield better outcomes than utilizing a single approach.

Translating biomarkers research to clinical care: applications and issues for rehabilomics

Traumatic brain injury is a leading cause of morbidity and mortality in adults and children in the United States. Despite steady improvement in our understanding of the pathophysiology of acquired brain injuries, there has been remarkably little improvement in brain injury therapies and/or pharmacologic treatments over the past decade. One of the reasons may be the inability to properly stratify subjects for clinical trials and/or to have real-time assessment of the effectiveness of a given intervention. It has been recognized for several decades that serum biomarkers may allow for more objective subject stratification as well as act as surrogate markers of treatment efficacy. Despite numerous studies, however, biomarkers are not currently part of clinical practice in either acquired brain injury or other neurologic or musculoskeletal disorders. The goals of this review article, therefore, are to use traumatic brain injury as a example to discuss the use of biomarkers in clinical and randomized controlled trials; to briefly discuss the field of neuroproteomics and its interface with neurologic interventions; and to provide an overview of the collaborative pathway between academia and industry, which needs to be an integral part of the translation of biomarkers from the bench to the bedside in any clinical population. Introduction of the concept of rehabilomics and implications of biomarker use for the physical medicine and rehabilitation physician also are discussed.

Common data elements for pediatric traumatic brain injury: recommendations from the working group on demographics and clinical assessment

The Common Data Elements (CDEs) initiative is a National Institutes of Health (NIH) interagency effort to standardize naming, definitions, and data structure for clinical research variables. Comparisons of the results of clinical studies of neurological disorders have been hampered by variability in data coding, definitions, and procedures for sample collection. The CDE project objective is to enable comparison of future clinical trials results in major neurological disorders, including traumatic brain injury (TBI), stroke, multiple sclerosis, and epilepsy. As part of this effort, recommendations for CDEs for research on TBI were developed through a 2009 multi-agency initiative. Following the initial recommendations of the Working Group on Demographics and Clinical Assessment, a separate workgroup developed recommendations on the coding of clinical and demographic variables specific to pediatric TBI studies for subjects younger than 18 years. This article summarizes the selection of measures by the Pediatric TBI Demographics and Clinical Assessment Working Group. The variables are grouped into modules which are grouped into categories. For consistency with other CDE working groups, each variable was classified by priority (core, supplemental, and emerging). Templates were produced to summarize coding formats, guide selection of data points, and provide procedural recommendations. This proposed standardization, together with the products of the other pediatric TBI working groups in imaging, biomarkers, and outcome assessment, will facilitate multi-center studies, comparison of results across studies, and high-quality meta-analyses of individual patient data.

A review of clinical trials of hypothermia treatment for severe traumatic brain injury

Clinical trials of hypothermia treatment of traumatic brain injury can be divided into (1) trials designed to abort the biochemical cascade after injury-neuroprotection, (2) trials primarily designed to test the effect of hypothermia in reducing elevated intracranial pressure (ICP), and (3) trials with features of both neuroprotection and elevated ICP control. Three of the four clinical trials testing hypothermia induction after failure of conventional means of ICP control showed decreased mortality rate, though sample sizes were small and findings were not always statistically significant. Nine randomized trials have tested hypothermia as a neuroprotectant, inducing it from 2.5 to 15 hours after injury and continuing it for a predetermined period of time regardless of ICP. Eight of these nine trials have been negative with three finding an effect in patients with evacuated hematomas, two of these if hypothermia is rendered before or soon after craniotomy. Despite extensive clinical testing over a range of treatment windows after injury, there is no evidence for the use of hypothermia as a neuroprotectant in patients with diffuse brain injury. Four randomized trials have features of neuroprotection and ICP control, randomizing and initiating hypothermia within 15 hours of injury and continuing hypothermia for the duration of ICP elevation. All found improved outcome and reduced ICP. Based on these findings and the negative results of neuroprotection trials that extended hypothermia for a defined period of time, it is likely that the mechanism of protection in these combined mechanism trials was early control of ICP. This literature suggests the need for clinical trials with two distinct objectives-(1) testing hypothermia for ICP control when conventional means (sedation and paralysis, mannitol, hyperventilation, and cerebrospinal fluid drainage) fail and (2) testing early induction of hypothermia before hematoma evacuation individualizing the duration of hypothermia to the patient's ICP responses.

Clinical report—Guidelines for the determination of brain death in infants and children: an update of the 1987 task force recommendations

OBJECTIVE

To review and revise the 1987 pediatric brain death guidelines.

METHODS

Relevant literature was reviewed. Recommendations were developed using the GRADE system.

CONCLUSIONS AND RECOMMENDATIONS

(1) Determination of brain death in term newborns, infants and children is a clinical diagnosis based on the absence of neurologic function with a known irreversible cause of coma. Because of insufficient data in the literature, recommendations for preterm infants less than 37 weeks gestational age are not included in this guideline. (2) Hypotension, hypothermia, and metabolic disturbances should be treated and corrected and medications that can interfere with the neurologic examination and apnea testing should be discontinued allowing for adequate clearance before proceeding with these evaluations. (3) Two examinations including apnea testing with each examination separated by an observation period are required. Examinations should be performed by different attending physicians. Apnea testing may be performed by the same physician. An observation period of 24 hours for term newborns (37 weeks gestational age) to 30 days of age, and 12 hours for infants and chi (> 30 days to 18 years) is recommended. The first examination determines the child has met the accepted neurologic examination criteria for brain death. The second examination confirms brain death based on an unchanged and irreversible condition. Assessment of neurologic function following cardiopulmonary resuscitation or other severe acute brain injuries should be deferred for 24 hours or longer if there are concerns or inconsistencies in the examination. (4) Apnea testing to support the diagnosis of brain death must be performed safely and requires documentation of an arterial Paco(2) 20 mm Hg above the baseline and ≥ 60 mm Hg with no respiratory effort during the testing period. If the apnea test cannot be safely completed, an ancillary study should be performed. (5) Ancillary studies (electroencephalogram and radionuclide cerebral blood flow) are not required to establish brain death and are not a substitute for the neurologic examination. Ancillary studies may be us d to assist the clinician in making the diagnosis of brain death (i) when components of the examination or apnea testing cannot be completed safely due to the underlying medical condition of the patient; (ii) if there is uncertainty about the results of the neurologic examination; (iii) if a medication effect may be present; or (iv) to reduce the inter-examination observation period. When ancillary studies are used, a second clinical examination and apnea test should be performed and components that can be completed must remain consistent with brain death. In this instance the observation interval may be shortened and the second neurologic examination and apnea test (or all components that are able to be completed safely) can be performed at any time thereafter. (6) Death is declared when the above criteria are fulfilled.

Targeted temperature management in critical care: a report and recommendations from five professional societies

OBJECTIVE

Representatives of five international critical care societies convened topic specialists and a nonexpert jury to review, assess, and report on studies of targeted temperature management and to provide clinical recommendations.

DATA SOURCES

Questions were allocated to experts who reviewed their areas, made formal presentations, and responded to questions. Jurors also performed independent searches. Sources used for consensus derived exclusively from peer-reviewed reports of human and animal studies.

STUDY SELECTION

Question-specific studies were selected from literature searches; jurors independently determined the relevance of each study included in the synthesis.

CONCLUSIONS AND RECOMMENDATIONS

1) The jury opines that the term "targeted temperature management" replace "therapeutic hypothermia." 2) The jury opines that descriptors (e.g., "mild") be replaced with explicit targeted temperature management profiles. 3) The jury opines that each report of a targeted temperature management trial enumerate the physiologic effects anticipated by the investigators and actually observed and/or measured in subjects in each arm of the trial as a strategy for increasing knowledge of the dose/duration/response characteristics of temperature management. This enumeration should be kept separate from the body of the report, be organized by body systems, and be made without assertions about the impact of any specific effect on the clinical outcome. 4) The jury STRONGLY RECOMMENDS targeted temperature management to a target of 32°C-34°C as the preferred treatment (vs. unstructured temperature management) of out-of-hospital adult cardiac arrest victims with a first registered electrocardiography rhythm of ventricular fibrillation or pulseless ventricular tachycardia and still unconscious after restoration of spontaneous circulation (strong recommendation, moderate quality of evidence). 5) The jury WEAKLY RECOMMENDS the use of targeted temperature management to 33°C-35.5°C (vs. less structured management) in the treatment of term newborns who sustained asphyxia and exhibit acidosis and/or encephalopathy (weak recommendation, moderate quality of evidence).

Pre-hospital hypothermia is not associated with increased survival after traumatic brain injury

BACKGROUND

Conclusions from in vivo and in vitro studies suggest hypothermia may be protective in traumatic brain injury (TBI). Few studies evaluated the effect of admission temperature on outcomes. The purpose of this study is to examine the relationship between admission hypothermia and mortality in patients with isolated, blunt, moderate to severe TBI.

METHODS

The Los Angeles Trauma Database was queried for all patients ≥ 14 y of age with isolated, blunt, moderate to severe TBI (head abbreviated injury score (AIS) ≥ 3, all other <3), admitted between 2005 and 2009. The study population was then stratified into two groups by admission temperature: hypothermic (≤ 35°C) and normothermic (>35°C). Demographic characteristics and outcomes were compared between groups. Logistic regression analysis was used to determine the relationship between admission hypothermia and mortality.

RESULTS

A total of 1834 patients were analyzed and then stratified into two groups: hypothermic (n = 44) and normothermic (n = 1790). There was a significant difference noted in overall mortality (25% versus 7%), with the hypothermic group being four times more likely to succumb to their injuries. After adjusting for confounding factors, admission hypothermia was independently associated with increased mortality (AOR 2.5; 95% CI 1.1-6.3; P = 0.04).

CONCLUSIONS

Although in-vivo and in-vitro studies demonstrate induced hypothermia may be protective in TBI, our study demonstrates that admission hypothermia was associated with increased mortality in isolated, blunt, moderate to severe TBI. Further prospective research is needed to elucidate the role of thermoregulation in patients sustaining TBI.

Brain-systemic temperature gradient is temperature-dependent in children with severe traumatic brain injury

OBJECTIVES

To understand the gradient between rectal and brain temperature in children after severe traumatic brain injury. We hypothesized that the rectal temperature and brain temperature gradient will be influenced by the child's body surface area and that this relationship will persist over physiologic temperature ranges.

DESIGN

Retrospective review of a prospectively collected pediatric neurotrauma registry.

SETTING

Academic, university-based pediatric neurotrauma program.

PATIENTS

Consecutive children (n = 40) with severe traumatic brain injury (Glasgow coma scale of <8) who underwent brain temperature monitoring (July 2003 to December 2008) were studied after informed consent was obtained. A subset of children (n = 24) were concurrently enrolled in a randomized, controlled clinical trial of early-moderate hypothermia for neuroprotection.

INTERVENTIONS

Data extraction of multiple clinical variables, including demographic data, body surface area, and rectal and brain temperature at recorded at hourly intervals.

MEASUREMENTS AND MAIN RESULTS

Paired brain and rectal temperature measurements (in degrees Celsius, n = 4369) were collected hourly and compared by using Pearson correlations. Patients were stratified according to body surface area (<1.0 m, 1.0-1.99 m, 2.0-2.99 m, and >3.0 m) and based on brain temperature (≤34.0, 34.1-36.0; 36.1-38, ≥38.1). Body surface area and brain temperature were compared between groups by using Pearson correlations with correction for repeated measures. Mean brain temperature-rectal temperature difference was calculated for stratified brain temperature ranges. Overall, brain and rectal temperatures were highly correlated (r = .86, p < .001). During brain hyperthermia, brain temperature-rectal temperature was similar to that reported in previous studies with brain temperature higher than rectal temperature (1.75 ± 0.4; r = .54). Surprisingly, this relationship was reversed during brain hypothermia (brain temperature-rectal temperature = -1.87 ± 0.8; r = .37), indicating a reversal of the brain-systemic temperature gradient. When stratified for body surface area, the correlation between rectal temperature and brain temperature remained strong (r = .78, 0.91, 0.79 and 0.95, respectively, p < .001). However, the correlation between brain temperature and rectal temperature was substantially decreased when stratified for brain temperature (r = .37, 0.58, 0.48, 0.54, p < .001). In particular, during moderate brain hypothermia (brain temperature ≤34), the correlation between brain temperature and rectal temperature was weakest, indicating the greatest variability during this condition which is often targeted for therapeutic trials.

CONCLUSIONS

Brain temperature and rectal temperature are generally well-correlated in children with traumatic brain injury. This relationship is different at the extremes of the physiologic temperature range, with the temperature gradient reversed during brain hypothermia and hyperthermia. Given that studies showing neuroprotection from hypothermia in animal models of brain injury generally target brain temperature, our data suggest the possibility that, if brain temperature were the therapeutic target in clinical trials, this would result in somewhat higher systemic temperature and potentially fewer side effects. This relationship may be exploited in future clinical trials to maintain brain hypothermia (for neurologic protection) at slightly higher systemic temperatures (and potentially fewer systemic side effects).

Contemporary management of traumatic intracranial hypertension: is there a role for therapeutic hypothermia?

OBJECTIVE

Intracranial hypertension (ICH) remains the single most difficult therapeutic challenge for the acute management of severe traumatic brain injury (TBI). We reviewed the published trials of therapeutic moderate hypothermia to determine its effect on ICH and compared its efficacy to other commonly used therapies for ICH.

METHODS

A PubMed database search was done using various combinations of the search terms "brain injury," "therapeutic hypothermia," "intracranial hypertension," "barbiturates," "mannitol," "hypertonic saline," "hyperventilation," "decompressive craniectomy," and "CSF drainage."

RESULTS

We identified 11 prospective randomized clinical TBI trials comparing hypothermia vs. normothermia treatment for which intracranial pressure (ICP) data was provided, and 6 prospective cohort studies that provided ICP data before and during hypothermia treatment. In addition, we identified 37 clinical TBI studies of lumbar CSF drainage, mannitol, hyperventilation, barbiturates, hypertonic saline, and decompressive craniectomy that provided pre- and posttreatment ICP data. Hypothermia was at least as effective as the traditional therapies for ICH (hyperventilation, mannitol, and barbiturates), but was less effective than hypertonic saline, lumbar CSF drainage, and decompressive craniectomy. Ultimately, however, therapeutic hypothermia does appear to have a favorable risk/benefit profile.

CONCLUSION

Therapeutic moderate hypothermia is as effective, or more effective, than most other treatments for ICH. If used for 2-3 days or less there is no evidence that it causes clinically significant adverse events. The lack of consistent evidence that hypothermia improves long-term neurologic outcome should not preclude consideration of its use for the primary treatment of ICH since no other ICP therapy is held to this standard.

Relationship between increases in pancreatic enzymes and cerebral events in children after traumatic brain injury

OBJECTIVE

To describe the risk factors of early and delayed increases in pancreatic enzymes (PE) in children after severe traumatic brain injury (TBI) and to determine if cerebral events (such as intracranial hemorrhage or intracranial hypertension) are associated with increases in PE.

DESIGN AND SETTINGS

Retrospective analysis of prospectively collected Pediatric Neurotrauma Registry for children with severe TBI (GCS ≤ 8). We assessed the association of clinical characteristics with the development of increases in PE using regression analyses.

PATIENTS

Fifty-one children with severe TBI were classified into three groups [normal PE; early PE (PE increases within first 24 h); delayed PE (PE increases after 24 h)].

MEASUREMENTS AND MAIN RESULTS

Increases in PE were observed in 29/51 children [57% total; n = 9 (18%) early; n = 20 (39%) delayed]. Multisystem trauma was more prevalent in patients with early increases in PE compared to those without increases in PE (70 vs. 30%, RR = 2.8, 95% CI 1.1-7) but not different between delayed PE and normal PE groups. In the bivariate analyses, increasing age (odds ratios, [95% CI]; 1.2, [1.05-1.4]), intracranial hypertension (14.6, [2.6-80.5]), intracranial hemorrhage (6.2, [1.15-33.7]), receipt of pentobarbital (9.3, [2.1-39.9]), mannitol (13.2, [2.7-62.2]), and vasoactive medications (6.9, [1.5-31.3]) were associated with the development of delayed increases in PE, whereas sex, initial Glasgow Coma Scale, severity of injury (PRISM, Injury Severity Score), therapeutic hypothermia, morphine and furosemide were not associated. Both intracranial hypertension and intracranial hemorrhage independently predicted the development of increases in PE (14.6, [2.6-80.5], and 9.1, [1.31-63.3], respectively).

CONCLUSIONS

Increases in PE, often used as the only measures of pancreatitis in children with other severe injuries, are common in children after severe TBI and delayed presentation appears related to intracranial events. This suggests a possible interaction between the brain and the gastrointestinal system, implying that disturbances in cerebral hemodynamics may lead to pancreatic dysfunction.

Severe traumatic brain injury in children elevates glial fibrillary acidic protein in cerebrospinal fluid and serum

OBJECTIVES

1) To determine the levels of glial fibrillary acidic protein (GFAP) in both cerebrospinal fluid and serum; 2) to determine whether serum GFAP levels correlate with functional outcome; and 3) to determine whether therapeutic hypothermia, as compared with normothermia, alters serum GFAP levels in children with severe traumatic brain injury (TBI).

DESIGN

Laboratory-based analyses; postrandomized, controlled trial.

SETTING

Four Canadian pediatric intensive care units and a university-affiliated laboratory.

PATIENTS

Twenty-seven children, aged 2-17 yrs, with severe TBI (Glasgow Coma Scale score of ≤ 8).

INTERVENTIONS

Hypothermia therapy (32.5°C) for 24 hrs with cooling started within 8 hrs of injury and rewarming at a rate of 0.5°C every 2 hrs or normothermia (37.0°C).

MEASUREMENTS AND MAIN RESULTS

GFAP was measured in cerebrospinal fluid and serum, using enzyme-linked immunosorbent assay. Levels of GFAP were maximal on day 1 post-TBI, with cerebrospinal fluid GFAP (15.5 ± 6.1 ng/mL) 25-fold higher than serum GFAP (0.6 ± 0.2 ng/mL). Cerebrospinal fluid GFAP normalized by day 7, whereas serum GFAP decreased gradually to reach a steady state by day 10. Serum GFAP measured on day 1 correlated with Pediatric Cerebral Performance Category scores determined at 6 months post-TBI (ρ = 0.527; p = .008) but failed to correlate with the injury scoring on admission, physiologic variables, or indices of injury measured on computerized tomography imaging. The areas under the receiver operating characteristic curves for pediatric intensive care unit day 1 serum GFAP in determining good outcome were 0.80 (pediatric cerebral performance category, 1-2; normal-mild disability) and 0.91 (pediatric cerebral performance category, 1-3; normal-moderate disability). For a serum GFAP cutoff level of 0.6 ng/mL, sensitivity and specificity were 88% to 90% and 43% to 71%, respectively. Serum GFAP levels were similar among children randomized to either therapeutic hypothermia or normothermia.

CONCLUSIONS

GFAP was markedly elevated in cerebrospinal fluid and serum in children after severe TBI and serum GFAP measured on pediatric intensive care unit day 1 correlated with functional outcome at 6 months. Hypothermia therapy did not alter serum GFAP levels compared with normothermia after severe TBI in children. Serum GFAP concentration, together with other biomarkers, may have prognostic value after TBI in children.

Brain temperature: heat production, elimination and clinical relevance

Neurological insults are a leading cause of morbidity and mortality, both in adults and especially in children. Among possible therapeutic strategies to limit clinical cerebral damage and improve outcomes, hypothermia remains a promising and beneficial approach. However, its advantages are still debated after decades of use. Studies in adults have generated conflicting results, whereas in children recent data even suggest that hypothermia may be detrimental. Is it because brain temperature physiology is not well understood and/or not applied properly, that hypothermia fails to convince clinicians of its potential benefits? Or is it because hypothermia is not, as believed, the optimal strategy to improve outcome in patients affected with an acute neurological insult? This review article should help to explain the fundamental physiological principles of brain heat production, distribution and elimination under normal conditions and discuss why hypothermia cannot yet be recommended routinely in the management of children affected with various neurological insults.

Autologous Bone Marrow Mononuclear Cell Therapy for Severe Traumatic Brain Injury in Children

BACKGROUND:

Severe traumatic brain injury (TBI) in children is associated with substantial long-term morbidity and mortality. Currently, there are no successful neuroprotective/neuroreparative treatments for TBI. Numerous preclinical studies suggest that bone marrow-derived mononuclear cells (BMMNCs), their derivative cells (marrow stromal cells), or similar cells (umbilical cord blood cells) offer neuroprotection.

OBJECTIVE:

To determine whether autologous BMMNCs are a safe treatment for severe TBI in children.

METHODS:

Ten children aged 5 to 14 years with a postresuscitation Glasgow Coma Scale of 5 to 8 were treated with 6 × 106 autologous BMMNCs/kg body weight delivered intravenously within 48 hours after TBI. To determine the safety of the procedure, systemic and cerebral hemodynamics were monitored during bone marrow harvest; infusion-related toxicity was determined by pediatric logistic organ dysfunction (PELOD) scores, hepatic enzymes, Murray lung injury scores, and renal function. Conventional magnetic resonance imaging (cMRI) data were obtained at 1 and 6 months postinjury, as were neuropsychological and functional outcome measures.

RESULTS:

All patients survived. There were no episodes of harvest-related depression of systemic or cerebral hemodynamics. There was no detectable infusion-related toxicity as determined by PELOD score, hepatic enzymes, Murray lung injury scores, or renal function. cMRI imaging comparing gray matter, white matter, and CSF volumes showed no reduction from 1 to 6 months postinjury. Dichotomized Glasgow Outcome Score at 6 months showed 70% with good outcomes and 30% with moderate to severe disability.

CONCLUSION:

Bone marrow harvest and intravenous mononuclear cell infusion as treatment for severe TBI in children is logistically feasible and safe.

Quo vadis 2010? - carpe diem: challenges and opportunities in pediatric traumatic brain injury

Traumatic brain injury (TBI) in infants and children remains a public health problem of enormous magnitude. It is a complex and heterogeneous condition that presents many diagnostic, therapeutic and prognostic challenges. A number of investigative teams are studying pediatric TBI both in experimental models and in clinical studies at the bedside. This review builds on work presented in a prior supplement to Developmental Neuroscience that was published in 2006, and addresses several active areas of research on this topic, including (1) the application of novel imaging methods, (2) the use of serum and/or CSF biomarkers of injury, (3) advances in neuromonitoring, (4) the development and testing of novel therapies, (5) developments in modeling pediatric TBI, (6) the consideration of a new approach to classification of pediatric TBI, and (7) assessing the potential impact of the development of pediatric and neonatal neurocritical care services on the management and outcome of pediatric TBI.

Impact of hypotension and low cerebral perfusion pressure on outcomes in children treated with hypothermia therapy following severe traumatic brain injury: a post hoc analysis of the Hypothermia Pediatric Head Injury Trial

Hypotension and low cerebral perfusion pressure are known to be associated with unfavorable outcome in children and adults with traumatic brain injury. Using the database from a previously published, randomized controlled trial of 24 h of hypothermia therapy in children with severe traumatic brain injury, we compared the number of patients with hypotension or low cerebral perfusion pressure between the hypothermia therapy and normothermia groups. We also determined the association between these physiologic insults and unfavorable outcome using regression analysis. There were more patients with episodes of hypotension or low cerebral perfusion pressure in the hypothermia therapy group than in the normothermia group. These physiologic insults were associated with unfavorable outcome in both intervention groups. Hypotension and low cerebral perfusion pressure should be anticipated and prevented in future trials of hypothermia therapy in patients with traumatic brain injury.

α-Synuclein levels are elevated in cerebrospinal fluid following traumatic brain injury in infants and children: the effect of therapeutic hypothermia

α-Synuclein is one of the most abundant proteins in presynaptic terminals. Normal expression of α-synuclein is essential for neuronal survival and it prevents the initiation of apoptosis in neurons through covalent cross-linking of cytochrome c released from mitochondria. Exocytosis of α-synuclein occurs with neuronal mitochondrial dysfunction, making its detection in cerebrospinal fluid (CSF) of children after severe traumatic brain injury (TBI) a potentially important marker of injury. Experimental therapeutic hypothermia (TH) improves mitochondrial function and attenuates cell death, and therefore may also affect CSF α-synuclein concentrations. We assessed α-synuclein levels in CSF of 47 infants and children with severe TBI using a commercial ELISA for detection of monomeric protein. 23 patients were randomized to TH based on published protocols where cooling (32-33°C) was initiated within 6-24 h, maintained for 48 h, and then followed by slow rewarming. CSF samples were obtained continuously via an intraventricular catheter for 6 days after TBI. Control CSF (n = 9) was sampled from children receiving lumbar puncture for CSF analysis of infection that was proven negative. Associations of initial Glasgow Coma Scale (GCS) score, age, gender, treatment, mechanism of injury and Glasgow Outcome Scale (GOS) score with CSF α-synuclein were compared by multivariate regression analysis. CSF α-synuclein levels were elevated in TBI patients compared to controls (p = 0.0093), with a temporal profile showing an early, approximately 5-fold increase on days 1-3 followed by a delayed, >10-fold increase on days 4-6 versus control. α-Synuclein levels were higher in patients treated with normothermia versus hypothermia (p = 0.0033), in patients aged <4 years versus ≥4 years (p < 0.0001), in females versus males (p = 0.0007), in nonaccidental TBI versus accidental TBI victims (p = 0.0003), and in patients with global versus focal injury on computed tomography of the brain (p = 0.046). Comparisons of CSF α-synuclein levels with initial GCS and GOS scores were not statistically significant. Further studies are needed to evaluate the conformational status of α-synuclein in CSF, and whether TH affects α-synuclein aggregation.

Prophylactic hypothermia for traumatic brain injury: a quantitative systematic review

INTRODUCTION

During the past 7 years, considerable new evidence has accumulated supporting the use of prophylactic hypothermia for traumatic brain injury (TBI). Studies can be divided into 2 broad categories: studies with protocols for cooling for a short, predetermined period (e.g., 24-48 h), and those that cool for longer periods and/or terminate based on the normalization of intracranial pressure (ICP). There have been no systematic reviews of hypothermia for TBI that include this recent new evidence.

METHODS

This analysis followed the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions and the QUOROM (quality of reporting of meta-analyses) statement. We developed a comprehensive search strategy to identify all randomized controlled trials (RCTs) comparing therapeutic hypothermia with standard management in TBI patients. We searched Embase, MEDLINE, Web of Science, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, ProceedingsFirst and PapersFirst. Additional relevant articles were identified by hand-searching conference proceedings and bibliographies. All stages of study identification and selection, quality assessment and analysis were conducted according to prospectively defined criteria. Study quality was determined by assessment of each study for the use of allocation concealment and outcome assessment blinding. Studies were divided into 2 a priori-defined subgroups for analysis based on cooling strategy: short term (< or = 48 h), and long term or goal-directed (> 48 h and/or continued until normalization of ICP). Outcomes included mortality and good neurologic outcome (defined as Glasgow Outcome Scale score of 4 or 5). Pooling of primary outcomes was completed using relative risk (RR) and reported with 95% confidence intervals (CIs).

RESULTS

Of 1709 articles, 12 studies with 1327 participants were selected for quantitative analysis. Eight of these studies cooled according to a long-term or goal-directed strategy, and 4 used a short-term strategy. Summary results demonstrated lower mortality (RR 0.73, 95% CI 0.62-0.85) and more common good neurologic outcome (RR 1.52, 95% CI 1.28-1.80). When only short-term cooling studies were analyzed, neither mortality (RR 0.98, 95% CI 0.75-1.30) nor neurologic outcome (RR 1.31, 95% CI 0.94-1.83) were improved. In 8 studies of long-term or goal-directed cooling, mortality was reduced (RR 0.62, 95% CI 0.51-0.76) and good neurologic outcome was more common (RR 1.68, 95% CI 1.44-1.96).

CONCLUSION

The best available evidence to date supports the use of early prophylactic mild-to-moderate hypothermia in patients with severe TBI (Glasgow Coma Scale score < or = 8) to decrease mortality and improve rates of good neurologic recovery. This treatment should be commenced as soon as possible after injury (e.g., in the emergency department after computed tomography) regardless of initial ICP, or before ICP is measured. Most studies report using a temperature of 32 degrees -34 degrees C. The maximal benefit occurred with a long-term or goal-directed cooling protocol, in which cooling was continued for at least 72 hours and/or until stable normalization of intracranial pressure for at least 24 hours was achieved. There is large potential for further research on this therapy in prehospital and emergency department settings.

Management of raised intracranial pressure

Appropriate management of raised intracranial pressure begins with stabilization of the patient and simultaneous assessment of the level of sensorium and the cause of raised intracranial pressure. Stabilization is initiated with securing the airway, ventilation and circulatory function. The identification of surgically remediable conditions is a priority. Emergent use of external ventricular drain or ventriculo-peritoneal shunt may be lifesaving in selected patients. In children with severe coma, signs of herniation or acutely elevated intracranial pressure, treatment should be started prior to imaging or invasive monitoring. Emergent use of hyperventilation and mannitol are life saving in such situations. Medical management involves careful use of head elevation, osmotic agents, and avoiding hypotonic fluids. Appropriate care also includes avoidance of aggravating factors. For refractory intracranial hypertension, barbiturate coma, hypothermia, or decompressive craniectomy should be considered.

Mild hypothermia therapy reduces blood glucose and lactate and improves neurologic outcomes in patients with severe traumatic brain injury

PURPOSE

The study aimed to investigate the association between blood glucose or lactate and the outcomes of severe traumatic brain injury (TBI), and to evaluate the effect of mild hypothermia therapy on glucose and lactate levels.

METHODS

Eighty-one patients with TBI were randomly divided into normothermia (n = 41) and mild hypothermia (n = 40) group. Body temperature of hypothermia group was maintained at 32.7°C for 72 hours. Arterial blood glucose and lactic acid were determined before and after hypothermia therapy. Glasgow Outcome Scale (GOS) score was assessed 3 months after the treatment.

RESULTS

The mean glucose (7.04 ± 0.51 vs 9.71 ± 1.63 mmol/L, P < .05) in the hypothermia group was lower than in the normothermia group after hypothermia therapy. There were more patients with good neurologic function (GOS 4-5) in the hypothermia group than in the normothermia group (75.0% vs 51.2%, P = .038). Multivariate regression analysis showed that blood glucose greater than 10 mmol/L (adjusted risk ratio, 5.7; 95% confidence interval, 1.4-13.2; P < .05) was an independent predictor for poor neurologic outcomes in these patients, and hypothermia therapy was an independent predictor for favorable outcomes (risk ratio, 4.9; 95% confidence interval, 1.0-15.6; P < .05). No significant association between lactate and GOS scores was identified in the multivariate analysis.

CONCLUSION

Hyperglycemia after TBI was associated with poor clinical outcomes, but the predictive value of blood lactate level requires further investigation. Hypothermia therapy improves neurologic outcomes in patients with severe TBI, and reduction in blood glucose may be partially responsible for the improved outcomes.

Endothelin-1 is increased in cerebrospinal fluid and associated with unfavorable outcomes in children after severe traumatic brain injury

Severe pediatric traumatic brain injury (TBI) is associated with unfavorable outcomes secondary to injury from activation of the inflammatory cascade, the release of excitotoxic neurotransmitters, and changes in the reactivity of cerebral vessels, causing ischemia. Hypoperfusion of injured brain tissues after TBI is also associated with unfavorable outcomes. Therapeutic hypothermia is an investigational treatment strategy for use in patients with severe TBI that has shown differential effects on various cerebrospinal fluid (CSF) mediators in pediatric patients. Endothelin-1 (ET-1) is a powerful vasoconstrictor that exerts its effects on the cerebrovascular endothelium for sustained periods after TBI. The purpose of this study was to determine if CSF concentrations of ET-1 are increased after severe TBI in children, and if they are associated with demographics and outcomes that are affected by therapeutic hypothermia. This was an ancillary study to a prospective, randomized-controlled trial of early hypothermia in a tertiary care pediatric intensive care unit. Children (n = 34, age 3 months-15 years) suffering from severe TBI were randomized to hypothermia (n = 19) and normothermia (n = 15) as part of the efficacy study. Children undergoing diagnostic lumbar puncture (n = 11) to rule out infection were used as controls. Patients received either mild to moderate hypothermia (32-33°C) or normothermia as part of their treatment protocol. CSF was serially collected during the first 5 days after TBI. ET-1 concentrations were quantitated in patient and control CSF samples by a validated ELISA in duplicate with a limit of quantification of 0.195 pg/mL. CSF ET-1 concentrations were increased by two- to threefold in children after TBI compared to controls, and the increase was sustained for up to 5 days post-TBI. This relationship was not affected by hypothermia, and there were no differences in ET-1 response between children with inflicted and accidental TBI. Group-based trajectory analysis revealed two distinct groups with similar ET-1 levels over time. Univariate analysis showed a significant association between ET-1 levels and Glasgow Outcome Scale (GOS) scores, for which higher ET-1 levels over time were associated with unfavorable outcomes. ET-1 is increased in children with severe TBI and is associated with unfavorable outcomes. This increase in ET-1 may mediate the hypoperfusion or cerebrovascular dysfunction accompanying severe TBI in children. Importantly, hypothermia does not affect the brain's ET-1 response as measured in the CSF.

Relationship of intracranial pressure and cerebral perfusion pressure with outcome in young children after severe traumatic brain injury

Traumatic brain injury (TBI) is the most common cause of death for children less than 18 years of age. Current standards of care for children with severe TBI include monitoring of intracranial pressure (ICP), and goal-directed therapies to minimize ICP and optimize cerebral perfusion pressure (CPP; the mathematical difference between the mean arterial pressure and ICP). Current guidelines for ICP and CPP thresholds suggest that age-based thresholds should be adopted, but few studies have included the youngest children affected by TBI (those <2 years of age). We performed a retrospective analysis of our pediatric neurotrauma database to determine if ICP and CPP thresholds associated with favorable neurological outcome could be determined, or if the number of episodic alterations in the parameters (ICP >15 or >20 mm Hg; CPP <40 mm Hg, <45 mm Hg or <50 mm Hg) was different between children with favorable and unfavorable outcomes (based on dichotomous Glasgow Outcome Scale score at 6 months after TBI). Data from 22 children (of whom 81% had suffered from inflicted childhood neurotrauma) were analyzed in the first 7 days. Children with unfavorable outcome had more hourly readings of CPP of <45 mm Hg compared to children with favorable outcome [median (25-75%): 2 (1-31) vs. 0 (0-2); p <0.05]. There was no difference between the number of hourly readings of ICP of >20 mm Hg between the outcome groups [median (25-75%): favorable 0 (0-1) vs. unfavorable 1 (0-4); p = 0.17]. To our knowledge, this is the first exploratory report to test if CPP and ICP thresholds can be established for this young population of children after TBI, and it suggests a CPP target threshold of 45 mm Hg. Despite good ICP control in this population, there was still a 50% incidence of unfavorable outcome, suggesting that there may be unique physiologic parameters that need to be targeted in infants with severe TBI. A prospective study is needed to fully determine what goals should be targeted for this vulnerable population.

Practitioner review: beyond shaken baby syndrome: what influences the outcomes for infants following traumatic brain injury?

BACKGROUND

Traumatic brain injury (TBI) in infancy is relatively common, and is likely to lead to poorer outcomes than injuries sustained later in childhood. While the headlines have been grabbed by infant TBI caused by abuse, often known as shaken baby syndrome, the evidence base for how to support children following TBI in infancy is thin. These children are likely to benefit from ongoing assessment and intervention, because brain injuries sustained in the first year of life can influence development in different ways over many years.

METHODS

A literature search was conducted and drawn together into a review aimed at informing practitioners working with children who had a brain injury in infancy. As there are so few evidence-based studies specifically looking at children who have sustained a TBI in infancy, ideas are drawn from a range of studies, including different age ranges and difficulties other than traumatic brain injury.

RESULTS

This paper outlines the issues around measuring outcomes for children following TBI in the first year of life. An explanation of outcomes which are more likely for children following TBI in infancy is provided, in the areas of mortality; convulsions; endocrine problems; sensory and motor skills; cognitive processing; language; academic attainments; executive functions; and psychosocial difficulties. The key factors influencing these outcomes are then set out, including severity of injury; pre-morbid situation; genetics; family factors and interventions.

CONCLUSIONS

Practitioners need to take a long-term, developmental view when assessing, understanding and supporting children who have sustained a TBI in their first year of life. The literature suggests some interventions which may be useful in prevention, acute care and longer-term rehabilitation, and further research is needed to assess their effectiveness.

How I cool children in neurocritical care

Brain injury is the leading cause of death in our pediatric ICU [Au et al. Crit Care Med 36:A128, 2008]. Clinical care for brain injury remains largely supportive. Therapeutic hypothermia has been shown to be effective in improving neurological outcome after adult ventricular-arrhythmia-induced cardiac arrest and neonatal asphyxia, and is under investigation as a neuroprotectant after cardiac arrest and traumatic brain injury in children in our ICU and other centers. To induce hypothermia in children comatose after cardiac arrest we target 32-34 degrees C using cooling blankets and intravenous iced saline as primary methods for induction, for 24-72 h duration with vigilant re-warming. The objective of this article is to share our hypothermia protocol for cooling children with acute brain injury.

Therapeutic hypothermia and traumatic brain injury

PURPOSE OF REVIEW

Therapeutic hypothermia after traumatic brain injury (TBI)? For the last 10 years, no topic has been more popular and more controversial among neurointensivists. This article reviews the most current findings (experimental, clinical, adult and pediatric TBI), as well as the clinical management of therapeutic hypothermia.

RECENT FINDINGS

Despite ample experimental evidence, the clinical utility of therapeutic hypothermia has still to be conclusively demonstrated in terms of reduced mortality or improved functional recovery after TBI (even in pediatric TBI). Current findings support that hypothermia should be initiated as soon as possible, for at least 48 h duration, and that outcome is worse when barbiturates are part of ICU management. Currently, available cooling techniques, including prehospital cooling protocols, expand and improve clinical management of therapeutic hypothermia.

SUMMARY

Taking into consideration all results from clinical hypothermia TBI studies discussion has to be focused around the possibility that a better outcome could be achieved if protocols for therapeutic hypothermia are reviewed. It is possible that the negative effects of the cooling and the rewarming procedure currently overshadow the neuroprotective effects.

Hypothermia reduces brain edema, spontaneous recurrent seizure attack, and learning memory deficits in the kainic acid treated rats

AIMS

It is unknown whether hypothermia can disrupt the progress of epileptogenesis. The present study aimed to determine the effect of hypothermia on brain edema and epileptogenesis and to establish whether brain edema is associated with epileptogenesis after severe status epilepticus (SE).

METHODOLOGY

Rats were injected with a single dose of Kainic acid (KA) to produce either chronic epileptic rats (rats with spontaneous recurrent seizure, SRS) or rats without spontaneous recurrent seizure (no-SRS rats). A second KA injection was used to induce SE in SRS rats and in no-SRS rats. The number of SRS was counted and the brain edema induced by SE was assessed by brain water content measurement. The cognitive function was assessed by the radial-arm maze (RAM) test.

RESULTS

A second KA injection resulted in brain edema that was more severe in SRS rats than in no-SRS rats. After second injection of KA, hypothermia treatment attenuated the KA induced brain edema and reduced the SRS attack in SRS rats. Additionally cognitive function was better in hypothermia-treated SRS rats than in nomothermia treated SRS rats 1 month after the second KA injection.

CONCLUSIONS

Hypothermia treatment immediately after SE not only exhibited protective effects against the chronic spontaneous recurrent convulsant seizures but also improved cognitive function. These antiepileptogenic properties of hypothermia may be related to its attenuating effect on brain edema induced by SE. They therefore suggest that brain edema may be involved in the progress of epileptogenesis.

Induced hypothermia for trauma: current research and practice

Induction of hypothermia with the goal of providing therapeutic benefit has been accepted for use in the clinical setting of adult cardiac arrest and neonatal hypoxic-ischemic encephalopathy (HIE). However, its potential as a treatment in trauma is not as well defined. This review discusses potential benefits and complications of induced hypothermia (IH) with emphasis on the current state of knowledge and practice in various types of trauma. There is excellent preclinical research showing that in cases of penetrating trauma with cardiac arrest, inducing hypothermia to 10 degrees C using cardiopulmonary bypass (CPB) could possibly save those otherwise likely to die without causing neurologic sequelae. A human trial of this intervention is about to get underway. Preclinical studies suggest that inducing hypothermia may be useful to delay cardiac arrest in penetrating trauma victims who are hypotensive. There is potential for IH to be used in cases of blunt trauma, but it has not been well studied. In the case of traumatic brain injury (TBI), clinical trials have shown conflicting results, despite almost uniform efficacy seen in preclinical experiments. Major studies are analyzed and ways to standardize its use and optimize future clinical trials are discussed. More preclinical and clinical research is needed to better define whether there could be a role for IH in the case of spinal cord injuries.

[Effects of induced hypothermia in critically ill children]

OBJECTIVE

To study the efficacy of induced hypothermia (IH) in children, its effect on hemodynamic, hematological, and biochemical parameters and its side effects.

DESIGN

Retrospective, observational study.

SETTING

Pediatric intensive care unit.

PATIENTS

Pediatric patients requiring induced hypothermia.

INTERVENTIONS

None.

DATA COLLECTED

The following variables were recorded prior to the initiation of IH and after 4, 24, 48, 72, and 120 hours: heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), diuresis, dose of inotropic, sedative, and muscle relaxant drugs, fluid balance, hematocrit, white cell count, white cell differential percentages, platelet count, blood levels of glucose, sodium, and potassium, C reactive protein, lactate, coagulation times, pressure ulcers, shivering, infections and death.

RESULTS

Thirty-one patients with a mean age of 20 months (SD: 39.8) were included in the study. The mean duration of IH was 3.97 days (range: 1 to 11 days). Among the IH effects, there was a significant fall in heart rate, with no changes in SBP, DBP, or diuresis. The blood tests revealed a progressive and significant fall in platelet count and an increase in C reactive protein levels. The fall in hematocrit and glucose and lactate levels was not significant. Positive cultures were detected in 25.8% of the patients during IH, most commonly from the bronchial aspirate (65%).

CONCLUSIONS

Induced hypothermia can be useful in some critically ill children. Tolerance is generally good and there are usually few side effects, which can be controlled through appropriate monitoring.

Impact of hypothermia in the rural, pediatric trauma patient

OBJECTIVE

Hypothermia is an independent predictor of mortality in adult trauma studies. However, the impact of hypothermia on the pediatric trauma population has not been described. The purpose of this study is to evaluate hypothermia as a cofactor to mortality, complications, and among survivors, hospital length of stay parameters in the pediatric trauma population.

DESIGN

Retrospective review of a prospectively collected database (National Trauma Registry of the American College of Surgeons) over a 5-yr period (July 2002 to June 2007).

SETTING

A rural, level I trauma center.

PATIENTS

One thousand six hundred twenty-nine pediatric patients admitted with a traumatic injury.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Multivariate regression models were used to evaluate the association of hypothermia with mortality, infectious complications, organ dysfunction, and among survivors, hospital length of stay parameters. Of 1,629 pediatric trauma patients admitted, 182 (11.1%) patients were hypothermic (temperature below 36 degrees C) on admission. Hypothermia had an adjusted odds ratio (AOR) of 2.41 (95% confidence interval [CI], 1.12-5.22, p = .025) for mortality. After controlling for covariates, hypothermia had associations with developing pneumonia (AOR, 0.185, 95% CI, 0.040-0.853; p = .031) and a bleeding diathesis (AOR, 3.14, 95% CI, 1.04-9.44; p = .042). The median days in the hospital, intensive care unit (ICU), and ventilator were longer in the hypothermic cohort; however, after controlling for covariates, hypothermia was not associated with differences in hospital days, ICU days, or ventilator days.

CONCLUSIONS

Hypothermia is a common problem at admission among pediatric trauma patients. Hypothermia is associated with an increase in the odds of death and the development of a bleeding diathesis, while having decreased odds for developing pneumonia. While the length of stay indicators were longer in the hypothermic cohort among survivors, no significant association was noted with hypothermia for hospital, ICU, or ventilator days after controlling for confounders.

Head trauma in children, part 1: admission, diagnostics, and findings

The objective of this study is to describe and to determine the preclinical situation and early in-clinical situation, diagnostic findings, and factors influencing the outcome of severe head trauma in children. Records of 48 children (0-16 years) were analyzed during a 3-year interval. Correlations with the outcome (Glasgow Outcome Scale) were determined by focusing on different scales, clinical findings, biochemistry, and clinical course features. The initial shock index had a major relevance (P = .0089). Systolic blood pressure (P = .0002) and bradycardia (P = .035) were important factors. Assessing the severity of trauma according to the Glasgow Coma Score, the most accurate parameter for outcome is based on the detailed quality of ''eye opening'' (P = .0155). Pupillary motoricity at the accident site (P = .002) and emergency room (P = .0004) are strong predictors. Preclinical measurements of stabilization and oxygenation have the same impact as the in-clinical management.

The evidence for hypothermia as a neuroprotectant in traumatic brain injury

This article reviews published experimental and clinical evidence for the benefits of modest hypothermia in the treatment of traumatic brain injury (TBI). Therapeutic hypothermia has been reported to improve outcome in several animal models of CNS injury and has been successfully translated to specific patient populations. A PubMed search for hypothermia and TBI was conducted, and important papers were selected for review. The research summarized was conducted at major academic institutions throughout the world. Experimental studies have emphasized that hypothermia can affect multiple pathophysiological mechanisms thought to participate in the detrimental consequences of TBI. Published data from several relevant clinical trials on the use of hypothermia in severely injured TBI patients are also reviewed. The consequences of mild to moderate levels of hypothermia introduced by different strategies to the head-injured patient for variable periods of time are discussed. Both experimental and clinical data support the beneficial effects of modest hypothermia following TBI in specific patient populations. Following on such single-institution studies, positive findings from multicenter TBI trials will be required before this experimental treatment can be considered standard of care.

Controversies of prophylactic hypothermia and the emerging use of brain tissue oxygen tension monitoring and decompressive craniectomy in traumatic brain-injured children

BACKGROUND

Despite being the leading cause of death and disability in the paediatric population, traumatic brain injury (TBI) in this group is largely understudied. Clinical practice within the paediatric intensive care unit (PICU) has been based upon adult guidelines however children are significantly different in terms of mechanism, pathophysiology and consequence of injury.

AIM

To review TBI management in the PICU and gain insight into potential management strategies.

METHOD

To conduct this review, a literature search was conducted using MEDLINE, PUBMED and The Cochrane Library using the following key words; traumatic brain injury; paediatric; hypothermia. There were no date restrictions applied to ensure that past studies, whose principles remain current were not excluded.

RESULTS

Three areas were identified from the literature search and will be discussed against current acknowledged treatment strategies: Prophylactic hypothermia, brain tissue oxygen tension monitoring and decompressive craniectomy.

CONCLUSION

Previous literature has failed to fully address paediatric specific management protocols and we therefore have little evidence-based guidance. This review has shown that there is an emerging and ongoing trend towards paediatric specific TBI research in particular the area of moderate prophylactic hypothermia (MPH).

Hypothermia in bleeding trauma: a friend or a foe?

The induction of hypothermia for cellular protection is well established in several clinical settings. Its role in trauma patients, however, is controversial. This review discusses the benefits and complications of induced hypothermia--emphasizing the current state of knowledge and potential applications in bleeding patients. Extensive pre-clinical data suggest that in advanced stages of shock, rapid cooling can protect cells during ischemia and reperfusion, decrease organ damage, and improve survival. Yet hypothermia is a double edged sword; unless carefully managed, its induction can be associated with a number of complications. Appropriate patient selection requires a thorough understanding of the pre-clinical literature. Clinicians must also appreciate the enormous influence that temperature modulation exerts on various cellular mechanisms. This manuscript aims to provide a balanced view of the published literature on this topic. While many of the advantageous molecular and physiological effects of induced hypothermia have been outlined in animal models, rigorous clinical investigations are needed to translate these promising findings into clinical practice.

Active cooling in traumatic brain-injured patients: a questionable therapy?

Hypothermia is shown to be beneficial for the outcome after a transient global brain ischaemia through its neuroprotective effect. Whether this is also the case after focal ischaemia, such as following a severe traumatic brain injury (TBI), has been investigated in numerous studies, some of which have shown a tendency towards an improved outcome, whereas others have not been able to demonstrate any beneficial effect. A Cochrane report concluded that the majority of the trials that have already been published have been of low quality, with unclear allocation concealment. If only high-quality trials are considered, TBI patients treated with active cooling were more likely to die, a conclusion supported by a recent high-quality Canadian trial on children. Still, there is a belief that a modified protocol with a shorter time from the accident to the start of active cooling, longer cooling and rewarming time and better control of blood pressure and intracranial pressure would be beneficial for TBI patients. This belief has led to the instigation of new trials in adults and in children, including these types of protocol adjustments. The present review provides a short summary of our present knowledge of the use of active cooling in TBI patients, and presents some tentative explanations as to why active cooling has not been shown to be effective for outcome after TBI. We focus particularly on the compromised circulation of the penumbra zone, which may be further reduced by the stress caused by the difference in thermostat and body temperature and by the hypothermia-induced more frequent use of vasoconstrictors, and by the increased risk of contusional bleedings under hypothermia. We suggest that high fever should be reduced pharmacologically.