Clinical trials in pediatric traumatic brain injury: unique challenges and potential responses

Best Practices for Obtaining Genomic Consent in Pediatric Traumatic Brain Injury Research

BACKGROUND

Precision health relies on large sample sizes to ensure adequate power, generalizability, and replicability; however, a critical first step to any study is the successful recruitment of participants.

OBJECTIVES

This study seeks to explore how the enrollment strategies used in a parent study contributed to the high consent rates, establish current best practices that can be used in future studies, and identify additional factors that contribute to consent into pediatric traumatic brain injury biobanks.

METHODS

Retrospective secondary analysis of data from a parent study with high consent rates was examined to explore factors affecting consent into biobanking studies.

RESULTS

Of the 76 subjects who were approached, met the eligibility criteria, and reviewed the consent form, only 16 (21.1%) declined to participate. The consented group (n = 60) represents 64.5% of those who met the eligibility criteria upon initial screening (n = 93) and 78.9% of those with confirmed eligibility (n = 76). Analysis of screening data suggested there were no major barriers to consenting individuals into this pediatric traumatic brain injury biobank.

DISCUSSION

There were no demographic or research-related characteristics that significantly explained enrollment. Ethically, to obtain true informed consent, parents need to understand only their child's diagnosis, prognosis, and medical care, as well as the purpose of the proposed research and its risks and benefits. Researchers need to implement best practices, including a comprehensive review of census data to identify eligible participants to approach, a prescreening protocol, and effective consenting process to obtain informed consent so that precision care initiatives can be pursued.

The Base Deficit, International Normalized Ratio, and Glasgow Coma Scale (BIG) Score, and Functional Outcome at Hospital Discharge in Children With Traumatic Brain Injury

OBJECTIVES

To examine the association of the base deficit, international normalized ratio, and Glasgow Coma Scale (BIG) score on emergency department arrival with functional dependence at hospital discharge (Pediatric Cerebral Performance Category ≥ 4) in pediatric multiple trauma patients with traumatic brain injury.

DESIGN

A retrospective cohort study of a pediatric trauma database from 2001 to 2018.

SETTING

Level 1 trauma program at a university-affiliated pediatric institution.

PATIENTS

Two to 17 years old children sustaining major blunt trauma including a traumatic brain injury and meeting trauma team activation criteria.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two investigators, blinded to the BIG score, determined discharge Pediatric Cerebral Performance Category scores. The BIG score was measured on emergency department arrival. The 609 study patients were 9.7 ± 4.4 years old with a median Injury Severity Score 22 (interquartile range, 12). One-hundred seventy-one of 609 (28%) had Pediatric Cerebral Performance Category greater than or equal to 4 (primary outcome). The BIG constituted a multivariable predictor of Pediatric Cerebral Performance Category greater than or equal to 4 (odds ratio, 2.39; 95% CI, 1.81-3.15) after adjustment for neurosurgery requirement (odds ratio, 2.83; 95% CI, 1.69-4.74), pupils fixed and dilated (odds ratio, 3.1; 95% CI, 1.49-6.38), and intubation at the scene or referral hospital (odds ratio, 2.82; 95% CI, 1.35-5.87) and other postulated predictors of poor outcome. The area under the BIG receiver operating characteristic curve was 0.87 (0.84-0.90). Using an optimal BIG cutoff less than or equal to 8, sensitivity and negative predictive value for functional dependence at discharge were 93% and 96%, respectively, compared with a sensitivity of 79% and negative predictive value of 91% with Glasgow Coma Scale less than or equal to 8. In children with Glasgow Coma Scale 3, the BIG score was associated with brain death (odds ratio, 2.13; 95% CI, 1.58-2.36). The BIG also predicted disposition to inpatient rehabilitation (odds ratio, 2.26; 95% CI, 2.17-2.35).

CONCLUSIONS

The BIG score is a simple, rapidly obtainable severity of illness score that constitutes an independent predictor of functional dependence at hospital discharge in pediatric trauma patients with traumatic brain injury. The BIG score may benefit Trauma and Neurocritical care programs in identifying ideal candidates for traumatic brain injury trials within the therapeutic window of treatment.

Clinical trials for pediatric traumatic brain injury: definition of insanity?

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in children both in the United States and throughout the world. Despite valiant efforts and multiple clinical trials completed over the last few decades, there are no high-level recommendations for pediatric TBI available in current guidelines. In this review, the authors explore key findings from the major pediatric clinical trials in children with TBI that have shaped present-day recommendations and the insights gained from them. The authors also offer a perspective on potential efforts to improve the efficacy of future clinical trials in children following TBI.

Multimodality neuromonitoring in severe pediatric traumatic brain injury

Each year, the annual hospitalization rates of traumatic brain injury (TBI) in children in the United States are 57.7 per 100K in the <5 years of age and 23.1 per 100K in the 5-14 years age group. Despite this, little is known about the pathophysiology of TBI in children and how to manage it most effectively. Historically, TBI management has been guided by clinical examination. This has been assisted progressively by clinical imaging, intracranial pressure (ICP) monitoring, and finally a software that can calculate optimal brain physiology. Multimodality monitoring affords clinicians an early indication of secondary insults to the recovering brain including raised ICP and decreased cerebral perfusion pressure. From variables such as ICP and arterial blood pressure, correlations can be drawn to determine parameters of cerebral autoregulation (pressure reactivity index) and "optimal cerebral perfusion pressure" at which the vasculature is most reactive. More recently, significant advances using both direct and near-infrared spectroscopy-derived brain oxygenation plus cerebral microdialysis to drive management have been described. Here in, we provide a perspective on the state-of-the-art techniques recently implemented in clinical practice for pediatric TBI.

U.S. Trends of ED Visits for Pediatric Traumatic Brain Injuries: Implications for Clinical Trials

Our goal in this paper was to use the 2006-2013 Nationwide Emergency Department Sample (NEDS) database to describe trends of annual patient number, patient demographics and hospital characteristics of pediatric traumatic brain injuries (TBI) treated in U.S. emergency departments (EDs); and to use the same database to estimate the available sample sizes for various clinical trials of pediatric TBI cases. National estimates of patient demographics and hospital characteristics were calculated for pediatric TBI. Simulation analyses assessed the potential number of pediatric TBI cases from randomly selected hospitals for inclusion in future clinical trials under different scenarios. Between 2006 and 2013, the NEDS database estimated that of the 215,204,932 children who visited the ED, 6,089,930 (2.83%) had a TBI diagnosis. During the study period in the US EDs, pediatric TBI patients increased by 34.1%. Simulation analyses suggest that hospital EDs with annual TBI ED visits >1000, Levels I and II Trauma Centers, pediatric hospitals, and teaching hospitals will likely provide ample cases for pediatric TBI studies. However, recruiting severe pediatric TBI cases for clinical trials from a limited number of hospital EDs will be challenging due to small sample sizes. Pediatric TBI-related ED visits in the U.S. increased by over 30% from 2006 to 2013. Including unspecified head injury cases with ICD-9-CM code 959.01 would significantly change the national estimates and demographic patterns of pediatric TBI cases. Future clinical trials of children with TBI should conduct a careful feasibility assessment to estimate their sample size and study power in selected study sites.

Challenges Enrolling Children Into Traumatic Brain Injury Trials: An Observational Study

OBJECTIVES

In preparation for a clinical trial of therapeutic agents for children with moderate-to-severe blunt traumatic brain injuries (TBIs) in emergency departments (EDs), we conducted this feasibility study to (1) determine the number and clinical characteristics of eligible children, (2) determine the timing of patient and guardian arrival to the ED, and (3) describe the heterogeneity of TBIs on computed tomography (CT) scans.

METHODS

We conducted a prospective observational study at 16 EDs of children ≤ 18 years of age presenting with blunt head trauma and Glasgow Coma Scale scores of 3-12. We documented the number of potentially eligible patients, timing of patient and guardian arrival, patient demographics and clinical characteristics, severity of injuries, and cranial CT findings.

RESULTS

We enrolled 295 eligible children at the 16 sites over 6 consecutive months. Cardiac arrest and nonsurvivable injuries were the most common characteristics that would exclude patients from a future trial. Most children arrived within 2 hours of injury, but most guardians did not arrive until 2-3 hours after the injury. There was a substantial range in types of TBIs, with subdural hemorrhages being the most common.

CONCLUSION

Enrolling children with moderate-to-severe TBI into time-sensitive clinical trials will require large numbers of sites and meticulous preparation and coordination and will prove challenging to obtain informed consent given the timing of patient and guardian arrival. The Federal Exception from Informed Consent for Emergency Research will be an important consideration for enrolling these children.

Informed consent in paediatric critical care research--a South African perspective

BACKGROUND

Medical care of critically ill and injured infants and children globally should be based on best research evidence to ensure safe, efficacious treatment. In South Africa and other low and middle-income countries, research is needed to optimise care and ensure rational, equitable allocation of scare paediatric critical care resources. Ethical oversight is essential for safe, appropriate research conduct. Informed consent by the parent or legal guardian is usually required for child research participation, but obtaining consent may be challenging in paediatric critical care research. Local regulations may also impede important research if overly restrictive. By narratively synthesising and contextualising the results of a comprehensive literature review, this paper describes ethical principles and regulations; potential barriers to obtaining prospective informed consent; and consent options in the context of paediatric critical care research in South Africa.

DISCUSSION

Voluntary prospective informed consent from a parent or legal guardian is a statutory requirement for child research participation in South Africa. However, parents of critically ill or injured children might be incapable of or unwilling to provide the level of consent required to uphold the ethical principle of autonomy. In emergency care research it may not be practical to obtain consent when urgent action is required. Therapeutic misconceptions and sociocultural and language issues are also barriers to obtaining valid consent. Alternative consent options for paediatric critical care research include a waiver or deferred consent for minimal risk and/or emergency research, whilst prospective informed consent is appropriate for randomised trials of novel therapies or devices. We propose that parents or legal guardians of critically ill or injured children should only be approached to consent for their child's participation in clinical research when it is ethically justifiable and in the best interests of both child participant and parent. Where appropriate, alternatives to prospective informed consent should be considered to ensure that important paediatric critical care research can be undertaken in South Africa, whilst being cognisant of research risk. This document could provide a basis for debate on consent options in paediatric critical care research and contribute to efforts to advocate for South African law reform.

Neutrophil elastase mediates acute pathogenesis and is a determinant of long-term behavioral recovery after traumatic injury to the immature brain

While neutrophil elastase (NE), released by activated neutrophils, is a key mediator of secondary pathogenesis in adult models of brain ischemia and spinal cord injury, no studies to date have examined this protease in the context of the injured immature brain, where there is notable vulnerability resulting from inadequate antioxidant reserves and prolonged exposure to infiltrating neutrophils. We thus reasoned that NE may be a key determinant of secondary pathogenesis, and as such, adversely influence long-term neurological recovery. To address this hypothesis, wild-type (WT) and NE knockout (KO) mice were subjected to a controlled cortical impact at post-natal day 21, approximating a toddler-aged child. To determine if NE is required for neutrophil infiltration into the injured brain, and whether this protease contributes to vasogenic edema, we quantified neutrophil numbers and measured water content in the brains of each of these genotypes. While leukocyte trafficking was indistinguishable between genotypes, vasogenic edema was markedly attenuated in the NE KO. To determine if early pathogenesis is dependent on NE, indices of cell death (TUNEL and activated caspase-3) were quantified across genotypes. NE KO mice showed a reduction in these markers of cell death in the injured hippocampus, which corresponded to greater preservation of neuronal integrity as well as reduced expression of heme oxygenase-1, a marker of oxidative stress. WT mice, treated with a competitive inhibitor of NE at 2, 6 and 12h post-injury, likewise showed a reduction in cell death and oxidative stress compared to vehicle-treated controls. We next examined the long-term behavioral and structural consequences of NE deficiency. NE KO mice showed an improvement in long-term spatial memory retention and amelioration of injury-induced hyperactivity. However, volumetric and stereological analyses found comparable tissue loss in the injured cortex and hippocampus independent of genotype. Further, WT mice treated acutely with the NE inhibitor showed no long-term behavioral or structural improvements. Together, these findings validate the central role of NE in both acute pathogenesis and chronic functional recovery, and support future exploration of the therapeutic window, taking into account the prolonged period of neutrophil trafficking into the injured immature brain.

A study of consent for participation in a non-therapeutic study in the pediatric intensive care population

OBJECTIVE

To document the legal guardian-related barriers to consent procurement, and their stated reasons for non-participation in a paediatric critical care research study.

STUDY DESIGN

A multicentre, prospective, cohort study.

PARTICIPANTS

Legal guardians of children who participated in a multicentre study on adrenal insufficiency in paediatric critical illness. Data were collected on all consent encounters in the main study.

METHODS

Screening data, reasons for consent not being obtained, paediatric risk of mortality (illness severity) scores and age were collected on all 1707 patients eligible for participation in the Adrenal Insufficiency Study.

RESULTS

The main barriers to approaching legal guardians for consent were lack of availability of the legal guardians (321/1707) and language barriers (84/1707). Legal guardians of 917 patients were approached with an overall consent rate of 42% (range 14-56% across the seven sites). 81% of the 528 legal guardians who declined consent provided an unsolicited reason for refusal. The three most commonly stated reasons were: being overwhelmed (117/429), not wanting anything else done to their child (63/429) and not wanting an additional medication (53/429). In addition, 14.2% cited research-related concerns as the reason for their non-participation.

CONCLUSIONS

Barriers to consent procurement in a non-therapeutic paediatric critical care study appear to occur at many levels with lack of availability of legal guardians, and legal guardians feeling overwhelmed, being the most commonly recorded reasons. Further research into the impact of these findings on the validity and generalisability of the results of such studies is necessary prior to the development and study of future consent models.

The neuroethics and neurolaw of brain injury

Neuroethics and neurolaw are fields of study that involve the interface of neuroscience with clinical and legal decision-making. The past two decades have seen increasing attention being paid to both fields, in large part because of the advances in neuroimaging techniques and improved ability to visualize and measure brain structure and function. Traumatic brain injury (TBI), along with its acute and chronic sequelae, has emerged as a focus of neuroethical issues, such as informed consent for treatment and research, diagnostic and prognostic uncertainties, and the subjectivity of interpretation of data. The law has also more frequently considered TBI in criminal settings for exculpation, mitigation and sentencing purposes and in tort and administrative law for personal injury, disability and worker's compensation cases. This article provides an overview of these topics with an emphasis on the current challenges that the neuroscience of TBI faces in the medicolegal arena.

Therapeutic hypothermia after pediatric cardiac arrest trials: the vanguard phase experience and implications for other trials

OBJECTIVE

To determine whether an 18-month vanguard phase, in the Therapeutic Hypothermia after Pediatric Cardiac Arrest trials, confirmed study feasibility and patient safety, a prerequisite to continued funding by the sponsor.

DESIGN

Randomized controlled trial.

SETTING

Pediatric intensive care and pediatric cardiac care units in 15 clinical sites in the United States and Canada.

PATIENTS

Children aged 48 hrs to 18 yrs of age, with return of circulation after cardiac arrest.

INTERVENTIONS

Therapeutic hypothermia vs. therapeutic normothermia.

MEASUREMENTS AND MAIN RESULTS

The first 15 of 20 potential sites to obtain Institutional Review Board and subcontract approvals were selected as vanguard sites. Institutional Review Board approvals were obtained 92 days (median, interquartile range 65-114) and subcontracts signed 34 days (interquartile range 20-48) after distribution. Sites screened subjects at 13 days (interquartile range 9-21) and enrolled the first subjects 64 days (interquartile range 13-154) after study launch. The recruitment milestone was reached 4 months ahead of schedule, with no safety concerns identified. Overall recruitment in this ongoing trial remains on target.

CONCLUSIONS

The Therapeutic Hypothermia after Pediatric Cardiac Arrest vanguard phase proved beneficial for the investigators and funding agency. Because complex multicenter trials are rarely ready to launch when grant funds are received, the vanguard allowed time to refine the protocol and recruitment approaches. Competition for vanguard positions led to expedient Institutional Review Board and subcontract completion. Early success and sustained momentum contributed to recruitment at or above goals. Financial risks to the sponsor were minimized by tying funding for the full trial to achieving prespecified milestones. A vanguard phase may be a desirable strategy for the successful conduct of other complex clinical trials.

US estimates of hospitalized children with severe traumatic brain injury: implications for clinical trials

OBJECTIVES

To estimate sample sizes available for clinical trials of severe traumatic brain injury (TBI) in children, we described the patient demographics and hospital characteristics associated with children hospitalized with severe TBI in the United States.

METHODS

We analyzed the 2006 Kids' Inpatient Database. Severe TBI hospitalizations were defined as children discharged with TBI who required mechanical ventilation or intubation. Types of high-volume severe TBI hospitals were categorized based on the numbers of discharged patients with severe TBI in 2006. National estimates of demographics and hospital characteristics were calculated for pediatric severe TBI. Simulation analyses were performed to assess the potential number of severe TBI cases from randomly selected hospitals for inclusion in future clinical trials.

RESULTS

The majority of children with severe TBI were discharged from either a children's unit in general hospitals (41%) or a nonchildren's hospital (34%). Less than 5% of all hospitals were high-volume TBI hospitals, which discharged >78% of severe TBI cases and were more likely to be a children's unit in a general hospital or a children's hospital. Simulation analyses indicate that there is a saturation point after which the benefit of adding additional recruitment sites decreases significantly.

CONCLUSIONS

Children with severe TBI are infrequent at any one hospital in the United States, and few hospitals treat large numbers of children with severe TBI. To effectively plan trials of therapies for severe TBI, much attention has to be paid to selecting the right types of centers to maximize enrollment efficiency.

Re-orientation of clinical research in traumatic brain injury: report of an international workshop on comparative effectiveness research

During the National Neurotrauma Symposium 2010, the DG Research of the European Commission and the National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH/NINDS) organized a workshop on comparative effectiveness research (CER) in traumatic brain injury (TBI). This workshop reviewed existing approaches to improve outcomes of TBI patients. It had two main outcomes: First, it initiated a process of re-orientation of clinical research in TBI. Second, it provided ideas for a potential collaboration between the European Commission and the NIH/NINDS to stimulate research in TBI. Advances in provision of care for TBI patients have resulted from observational studies, guideline development, and meta-analyses of individual patient data. In contrast, randomized controlled trials have not led to any identifiable major advances. Rigorous protocols and tightly selected populations constrain generalizability. The workshop addressed additional research approaches, summarized the greatest unmet needs, and highlighted priorities for future research. The collection of high-quality clinical databases, associated with systems biology and CER, offers substantial opportunities. Systems biology aims to identify multiple factors contributing to a disease and addresses complex interactions. Effectiveness research aims to measure benefits and risks of systems of care and interventions in ordinary settings and broader populations. These approaches have great potential for TBI research. Although not new, they still need to be introduced to and accepted by TBI researchers as instruments for clinical research. As with therapeutic targets in individual patient management, so it is with research tools: one size does not fit all.

Factors affecting consent in pediatric critical care research

PURPOSE

Consent for research is a difficult and unpredictable process in pediatric critical care populations. The objectives of this study were to describe consent rates in pediatric critical care research and their association with patient, legal guardian, consent process, and study design-related factors.

METHODS

A prospective, cohort study was conducted from 2009 to 2010 in six tertiary care pediatric intensive care units (PICU) in Canada with legal guardians of patients who were approached for consent for any ongoing PICU research study. Data were recorded on details of the consent process for all consent encounters.

RESULTS

We recorded 271 consent encounters. The overall consent rate was 80.1% (217/271). We observed higher consent rates when the research assistant was introduced by a member of the clinical team prior to approaching the family (89.7 vs. 77.7%; P = 0.04). Legal guardians of cardiac surgery patients were less likely to provide consent than those of all other patients (75.3 vs. 86.0%; P = 0.03). There was no difference in consent rates between therapeutic (117/145, 80.7%) versus non-therapeutic studies (100/126, 79.4%; P = 0.88).

CONCLUSION

This study provides future researchers with consent data for determination of recruitment rates, sample sizes, budget estimations, and study timelines. Future pediatric critical care studies should consider incorporating the lower consent rates in cardiac surgery patients and routine introduction of the research assistant to the family by a member of the patient's care team into their study designs. The potential influence of parental factors on consent rates in pediatric critical care studies requires further research.

Cerebral oximetry for pediatric anesthesia: why do intelligent clinicians disagree?

Reflectance near-infrared spectroscopy has been used to measure cortical tissue oximetry for more than 30 years. In that time, many centers have adopted the routine use of the cerebral oximeter for children having repair of congenital heart lesions, while some prominent academic centers have resisted routine use of these monitors citing lack of definitive evidence for outcome benefit. In this review, we provide an overview of the method used to measure cerebral oximetry, as well as validation and clinical outcome data that have accrued from the use of cerebral oximeters. We discuss the peculiarities of evidentiary review for monitoring devices, and the confounding errors that occur when a monitor is evaluated as a therapeutic intervention. We outline the physiologic basis of cerebral desaturation and the shifts in practice that have occurred with implementation of NIRS monitoring.

Clinical management and functional neuromonitoring in traumatic brain injury in children

PURPOSE OF REVIEW

Traumatic brain injury is the main cause of childhood disability and death. In this review, we highlight recent original findings and emerging themes from published literature on children with serious traumatic brain injury.

RECENT FINDINGS

We focus this review on lessons learned from our recent randomized clinical trial of hypothermia therapy in severe traumatic brain injury in children and on bedside neuromonitoring. We propose that integrating the measurement of biomarkers into clinical care as surrogate endpoints and as potential prognostic markers would allow us to evaluate earlier the effect of injury and clinical care in children after traumatic brain injury. Several methods are now more readily available to monitor cerebral physiology in children. These methods include indices evaluating the integrity of cerebral autoregulation, such as the pressure reactivity index derived from values obtained from intracranial pressure measurements, flow velocity measurements from transcranial Doppler ultrasonography or from cerebral oximetry. Other methods allow the evaluation of coma with the nonlinear analysis of electroencephalography or the evaluation of cerebral metabolism and cell death pathways with biomarkers from serum, cerebral spinal fluid, and cerebral microdialysis.

SUMMARY

We suggest expanding clinical functional neuromonitoring to help clinicians understand the burden of exposure to physiological variables and response to therapies during intensive care in order to enhance the management of critically ill children with traumatic brain injury.

Mitochondrial mechanisms of cell death and neuroprotection in pediatric ischemic and traumatic brain injury

There are several forms of acute pediatric brain injury, including neonatal asphyxia, pediatric cardiac arrest with global ischemia, and head trauma, that result in devastating, lifelong neurologic impairment. The only clinical intervention that appears neuroprotective is hypothermia initiated soon after the initial injury. Evidence indicates that oxidative stress, mitochondrial dysfunction, and impaired cerebral energy metabolism contribute to the brain cell death that is responsible for much of the poor neurologic outcome from these events. Recent results obtained from both in vitro and animal models of neuronal death in the immature brain point toward several molecular mechanisms that are either induced or promoted by oxidative modification of macromolecules, including consumption of cytosolic and mitochondrial NAD(+) by poly-ADP ribose polymerase, opening of the mitochondrial inner membrane permeability transition pore, and inactivation of key, rate-limiting metabolic enzymes, e.g., the pyruvate dehydrogenase complex. In addition, the relative abundance of pro-apoptotic proteins in immature brains and neurons, and particularly within their mitochondria, predisposes these cells to the intrinsic, mitochondrial pathway of apoptosis, mediated by Bax- or Bak-triggered release of proteins into the cytosol through the mitochondrial outer membrane. Based on these pathways of cell dysfunction and death, several approaches toward neuroprotection are being investigated that show promise toward clinical translation. These strategies include minimizing oxidative stress by avoiding unnecessary hyperoxia, promoting aerobic energy metabolism by repletion of NAD(+) and by providing alternative oxidative fuels, e.g., ketone bodies, directly interfering with apoptotic pathways at the mitochondrial level, and pharmacologic induction of antioxidant and anti-inflammatory gene expression.

Improving outcomes in pediatric trauma care: essential characteristics of the trauma center

The best outcome after pediatric injury can be anticipated when the entire trauma team is prepared, knowledgeable, and appreciative of the unique aspects of pediatric trauma and pays strict attention to all aspects of the care of the injured child. Five aspects should be considered essential elements in the delivery of care by any trauma team: preparation, equipment, and training; prevention of secondary insults after brain injury; the ability to recognize when nonoperative therapy should not be attempted or when it should be abandoned; consideration of the psychological impact of injury on a child; and, the role of trauma centers in injury prevention. Each of these areas encompasses important unanswered questions.

Pilot study to determine the hemodynamic safety and feasibility of magnesium sulfate infusion in children with severe traumatic brain injury

OBJECTIVE

Magnesium sulfate is neuroprotective in preclinical models, but there are limited safety data regarding its clinical use for pediatric traumatic brain injury. We conducted a pilot study in children with severe traumatic brain injury to a) examine if magnesium sulfate decreases mean arterial pressure, decreases cerebral perfusion pressure, increases intracranial pressure, or adversely effects cardiac conduction; and b) determine the feasibility of a multiple-center trial of magnesium sulfate.

DESIGN

Double-blinded, placebo-controlled, randomized pilot trial with repeated measurement of hemodynamic variables.

SETTING

Two pediatric trauma centers.

PATIENTS

Six children (3 months to 18 yrs) with severe traumatic brain injury.

INTERVENTIONS

: Magnesium sulfate (50 mg/kg) bolus followed by (8.3 mg/kg/hr) infusion for 24 hr vs. equivolume placebo.

MEASUREMENTS AND MAIN RESULTS

We screened 96 patients with severe traumatic brain injury during 24 months; 20 were eligible for enrollment, six provided informed consent, four received magnesium sulfate, and two received placebo. Before and after study drug infusion, we repeatedly measured blood ionized magnesium concentration, mean arterial pressure, cerebral perfusion pressure, intracranial pressure, heart rate, and corrected QT interval. Mean age (7.9 yrs), mean highest Glasgow Coma Scale score (6), gender (33% boys), inflicted injury rate (17%), and case mortality rate (17%) did not differ between those enrolled and those not enrolled. Compared with baseline, magnesium sulfate did not change cerebral perfusion pressure, intracranial pressure, heart rate, or corrected QT interval. Mean arterial pressure was unchanged until the late phase of magnesium sulfate infusion, when mean arterial pressure rose (82 +/- 5 vs. 93 +/- 6 mm Hg, p < .05). Sixty-four percent of corrected QT interval determinations obtained in the first 6 days after injury exceeded 440 msecs; 12% were >600 msecs.

CONCLUSIONS

In children with severe traumatic brain injury, magnesium sulfate administration did not decrease mean arterial pressure or cerebral perfusion pressure or adversely effect cardiac conduction. Our data suggest that enrollment of brain-injured children in a therapeutic trial remains challenging. These results provide information important for clinical trials of magnesium sulfate in children with severe traumatic brain injury.