Variables affecting outcome from severe brain injury in children

Development of a Randomized Trial Comparing ICP-Monitor-Based Management of Severe Pediatric Traumatic Brain Injury to Management Based on Imaging and Clinical Examination Without ICP Monitoring-Study Protocol

BACKGROUND AND OBJECTIVES

Traumatic brain injury (TBI) is a major global public health problem. It is a leading cause of death and disability in children and adolescents worldwide. Although increased intracranial pressure (ICP) is common and associated with death and poor outcome after pediatric TBI, the efficacy of current ICP-based management remains controversial. We intend to provide Class I evidence testing the efficacy of a protocol based on current ICP monitor-based management vs care based on imaging and clinical examination without ICP monitoring in pediatric severe TBI.

METHODS

A phase III, multicenter, parallel-group, randomized superiority trial performed in intensive care units in Central and South America to determine the impact on 6-month outcome of children aged 1-12 years with severe TBI (age-appropriate Glasgow Coma Scale score ≤8) randomized to ICP-based or non-ICP-based management.

EXPECTED OUTCOMES

Primary outcome is 6-month Pediatric Quality of Life. Secondary outcomes are 3-month Pediatric Quality of Life, mortality, 3-month and 6-month Pediatric extended Glasgow Outcome Score, intensive care unit length of stay, and number of interventions focused on treating measured or suspected intracranial hypertension.

DISCUSSION

This is not a study of the value of knowing the ICP in sTBI. This research question is protocol-based. We are investigating the added value of protocolized ICP management to treatment based on imaging and clinical examination in the global population of severe pediatric TBI. Demonstrating efficacy should standardize ICP monitoring in severe pediatric TBI. Alternate results should prompt reassessment of how and in which patients ICP data should be applied in neurotrauma care.

Invasive Neuromonitoring Modalities in the Pediatric Population

Invasive neuromonitoring has become an important part of pediatric neurocritical care, as neuromonitoring devices provide objective data that can guide patient management in real time. New modalities continue to emerge, allowing clinicians to integrate data that reflect different aspects of cerebral function to optimize patient management. Currently, available common invasive neuromonitoring devices that have been studied in the pediatric population include the intracranial pressure monitor, brain tissue oxygenation monitor, jugular venous oximetry, cerebral microdialysis, and thermal diffusion flowmetry. In this review, we describe these neuromonitoring technologies, including their mechanisms of function, indications for use, advantages and disadvantages, and efficacy, in pediatric neurocritical care settings with respect to patient outcomes.

Catheter-associated deep vein thrombosis in children with severe traumatic brain injury: A single-center experience

BACKGROUND

This study was performed to describe the single-center experience of deep vein thrombosis (DVT) in children with severe traumatic brain injury (sTBI) who were mechanically ventilated with a central line, and to identify potentially modifiable risk factors. It was hypothesized that children with DVT would have a longer duration of central venous line (CVL) and a higher use of hypertonic saline (HTS) compared to those without DVT.

PROCEDURE/METHODS

This was a retrospective study of children (0-18 years) with sTBI, who were intubated, had a CVL, and a minimum intensive care unit (ICU) stay of 3 days. Children were analyzed by the presence or absence of DVT. HTS use was evaluated using milliliter per kilogram (ml/kg) of 3% equivalents. Univariable and multivariable logistic regression models were used to determine which factors were associated with DVT.

RESULTS

Seventy-seven children met inclusion criteria, 23 (29.9%) had a DVT detected in an extremity. On univariable analysis, children with DVT identified in an extremity had prolonged CVL use (14 vs. 8.5 days, p = .021) and longer duration of mechanical ventilation (15 vs. 10 days, p = .013). HTS 3% equivalent ml/kg was not different between groups. On multivariable analysis, mechanical ventilation duration was associated with DVT detection in an extremity, whereas neither CVL duration nor HTS use had an association.

CONCLUSIONS

There was a high incidence of extremity DVT detected in children with sTBI who received invasive mechanical ventilation and had a CVL. HTS administration was not associated with DVT detection in an extremity.

Intracranial and Cerebral Perfusion Pressure Thresholds Associated With Inhospital Mortality Across Pediatric Neurocritical Care

OBJECTIVES

Targets for treatment of raised intracranial pressure or decreased cerebral perfusion pressure in pediatric neurocritical care are not well defined. Current pediatric guidelines, based on traumatic brain injury, suggest an intracranial pressure target of less than 20 mm Hg and cerebral perfusion pressure minimum of 40-50 mm Hg, with possible age dependence of cerebral perfusion pressure. We sought to define intracranial pressure and cerebral perfusion pressure thresholds associated with inhospital mortality across a large single-center pediatric neurocritical care cohort.

DESIGN

Retrospective chart review.

SETTING

PICU, single quaternary-care center.

PATIENTS

Individuals receiving intracranial pressure monitoring from January 2012 to December 2016.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Intracranial pressure and cerebral perfusion pressure measurements from 262 neurocritical care patients (87 traumatic brain injury and 175 nontraumatic brain injury; 63% male; 8.3 ± 5.8 yr; mortality 11.1%). Mean intracranial pressure and cerebral perfusion pressure had area under the receiver operating characteristic curves of 0.75 and 0.64, respectively, for association of inhospital mortality. Cerebral perfusion pressure cut points increased with age (< 2 yr = 47, 2 to < 8 yr = 58 mm Hg, ≥ 8 yr = 73 mm Hg). In the traumatic brain injury subset, mean intracranial pressure and cerebral perfusion pressure had area under the receiver operating characteristic curves of 0.70 and 0.78, respectively, for association of inhospital mortality. Traumatic brain injury cerebral perfusion pressure cut points increased with age (< 2 yr = 45, 2 to < 8 yr = 57, ≥ 8 yr = 68 mm Hg). Mean intracranial pressure greater than 15 mm Hg, male sex, and traumatic brain injury status were independently associated with inhospital mortality (odds ratio, 14.23 [5.55-36.46], 2.77 [1.04-7.39], and 2.57 [1.03-6.38], respectively; all p < 0.05). Mean cerebral perfusion pressure less than 67 mm Hg and traumatic brain injury status were independently associated with inhospital mortality (odds ratio, 5.16 [2.05-12.98] and 3.71 [1.55-8.91], respectively; both p < 0.01). In the nontraumatic brain injury subset, mean intracranial pressure had an area under the receiver operating characteristic curve 0.77 with an intracranial pressure cut point of 15 mm Hg, whereas mean cerebral perfusion pressure was not predictive of inhospital mortality.

CONCLUSIONS

We identified mean intracranial pressure thresholds, utilizing receiver operating characteristic and regression analyses, associated with inhospital mortality that is below current guidelines-based treatment targets in both traumatic brain injury and nontraumatic brain injury patients, and age-dependent cerebral perfusion pressure thresholds associated with inhospital mortality that were above current guidelines-based targets in traumatic brain injury patients. Further study is warranted to identify data-driven intracranial pressure and cerebral perfusion pressure targets in children undergoing intracranial pressure monitoring, whether for traumatic brain injury or other indications.

Approaches to Multimodality Monitoring in Pediatric Traumatic Brain Injury

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in children. Improved methods of monitoring real-time cerebral physiology are needed to better understand when secondary brain injury develops and what treatment strategies may alleviate or prevent such injury. In this review, we discuss emerging technologies that exist to better understand intracranial pressure (ICP), cerebral blood flow, metabolism, oxygenation and electrical activity. We also discuss approaches to integrating these data as part of a multimodality monitoring strategy to improve patient care.

Children With Severe Traumatic Brain Injury, Intracranial Pressure, Cerebral Perfusion Pressure, What Does it Mean? A Review of the Literature

Severe traumatic brain injury is a leading cause of morbidity and mortality in children. In 2003 the Brain Trauma Foundation released guidelines that have since been updated (2010) and have helped standardize and improve care. One area of care that remains controversial is whether the placement of an intracranial pressure monitor is advantageous in the management of traumatic brain injury. Another aspect of care that is widely debated is whether management after traumatic brain injury should be based on intracranial pressure-directed therapy, cerebral perfusion pressure-directed therapy, or a combination of the two. The aim of this article was to provide an overview and review the current evidence regarding these questions.

Management of Pediatric Severe Traumatic Brain Injury: 2019 Consensus and Guidelines-Based Algorithm for First and Second Tier Therapies

OBJECTIVES

To produce a treatment algorithm for the ICU management of infants, children, and adolescents with severe traumatic brain injury.

DATA SOURCES

Studies included in the 2019 Guidelines for the Management of Pediatric Severe Traumatic Brain Injury (Glasgow Coma Scale score ≤ 8), consensus when evidence was insufficient to formulate a fully evidence-based approach, and selected protocols from included studies.

DATA SYNTHESIS

Baseline care germane to all pediatric patients with severe traumatic brain injury along with two tiers of therapy were formulated. An approach to emergent management of the crisis scenario of cerebral herniation was also included. The first tier of therapy focuses on three therapeutic targets, namely preventing and/or treating intracranial hypertension, optimizing cerebral perfusion pressure, and optimizing partial pressure of brain tissue oxygen (when monitored). The second tier of therapy focuses on decompressive craniectomy surgery, barbiturate infusion, late application of hypothermia, induced hyperventilation, and hyperosmolar therapies.

CONCLUSIONS

This article provides an algorithm of clinical practice for the bedside practitioner based on the available evidence, treatment protocols described in the articles included in the 2019 guidelines, and consensus that reflects a logical approach to mitigate intracranial hypertension, optimize cerebral perfusion, and improve outcomes in the setting of pediatric severe traumatic brain injury.

Effectiveness of Pharmacological Therapies for Intracranial Hypertension in Children With Severe Traumatic Brain Injury--Results From an Automated Data Collection System Time-Synched to Drug Administration

OBJECTIVES

To describe acute cerebral hemodynamic effects of medications commonly used to treat intracranial hypertension in children with traumatic brain injury. Currently, data supporting the efficacy of these medications are insufficient.

DESIGN

In this prospective observational study, intracranial hypertension (intracranial pressure ≥ 20 mm Hg for > 5 min) was treated by clinical protocol. Administration times of medications for intracranial hypertension (fentanyl, 3% hypertonic saline, mannitol, and pentobarbital) were prospectively recorded and synchronized with an automated database that collected intracranial pressure and cerebral perfusion pressure every 5 seconds. Intracranial pressure crises confounded by external stimulation or mechanical ventilator adjustments were excluded. Mean intracranial pressure and cerebral perfusion pressure from epochs following drug administration were compared with baseline values using Kruskal-Wallis analysis of variance and Dunn test. Frailty modeling was used to analyze the time to intracranial pressure crisis resolution. Mixed-effect models compared intracranial pressure and cerebral perfusion pressure 5 minutes after the medication versus baseline and rates of treatment failure.

SETTING

A tertiary care children's hospital.

PATIENTS

Children with severe traumatic brain injury (Glasgow Coma Scale score ≤ 8).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We analyzed 196 doses of fentanyl, hypertonic saline, mannitol, and pentobarbital administered to 16 children (median: 12 doses per patient). Overall, intracranial pressure significantly decreased following the administration of fentanyl, hypertonic saline, and pentobarbital. After controlling for administration of multiple medications, intracranial pressure was decreased following hypertonic saline and pentobarbital administration; cerebral perfusion pressure was decreased following fentanyl and was increased following hypertonic saline administration. After adjusting for significant covariates (including age, Glasgow Coma Scale score, and intracranial pressure), hypertonic saline was associated with a two-fold faster resolution of intracranial hypertension than either fentanyl or pentobarbital. Fentanyl was significantly associated with the most frequent treatment failure.

CONCLUSIONS

Intracranial pressure decreased after multiple drug administrations, but hypertonic saline may warrant consideration as the first-line drug for treating intracranial hypertension, as it was associated with the most favorable cerebral hemodynamics and fastest resolution of intracranial hypertension.

Intracranial pressure monitoring among children with severe traumatic brain injury

OBJECT Well-designed studies linking intracranial pressure (ICP) monitoring with improved outcomes among children with severe traumatic brain injury (TBI) are lacking. The main objective of this study was to examine the relationship between ICP monitoring in children and in-hospital mortality following severe TBI. METHODS An observational study was conducted using data derived from 153 adult or mixed (adult and pediatric) trauma centers participating in the American College of Surgeons (ACS) Trauma Quality Improvement Program (TQIP) and 29 pediatric trauma centers participating in the pediatric pilot TQIP between 2010 and 2012. Random-intercept multilevel modeling was used to examine the association between ICP monitoring and in-hospital mortality among children with severe TBI ≤16 years of age after adjusting for important confounders. This association was evaluated at the patient level and at the hospital level. In a sensitivity analysis, this association was reexamined in a propensity-matched cohort. RESULTS A total of 1705 children with severe TBI were included in the study cohort. The overall in-hospital mortality was 14.3% of patients (n = 243), whereas the mortality of the 273 patients (16%) who underwent invasive ICP monitoring was 11% (n = 30). After adjusting for patient- and hospital-level characteristics, ICP monitoring was associated with lower in-hospital mortality (adjusted OR 0.50; 95% CI 0.30-0.85; p = 0.01). It is possible that patients who were managed with ICP monitoring were selected because of an anticipated favorable or unfavorable outcome. To further address this potential selection bias, the analysis was repeated with the hospital-specific rate of ICP monitoring use as the exposure. The adjusted OR for death of children treated at high ICP-use hospitals was 0.49 compared with those treated at low ICP-use hospitals (95% CI 0.31-0.78; p = 0.003). Variations in ICP monitoring use accounted for 15.9% of the interhospital variation in mortality among children with severe TBI. Similar results were obtained after analyzing the data using propensity score-matching methods. CONCLUSIONS In this observational study, ICP monitoring use was associated with lower hospital mortality at both the patient and hospital levels. However, the contribution of variable ICP monitoring rates to interhospital variation in pediatric TBI mortality was modest.

Variations of the blood gas levels and thermodilutional parameters during ICP monitoring after severe head trauma in children

PURPOSE

The purpose of this study was to define, in children following head trauma and GSC ≤ 8, at which level of intracranial pressure (ICP), the thermodilutional, and gas analytic parameters implicated in secondary cerebral insults shows initial changes.

METHODS

We enrolled in the study 56 patients: 30 males and 26 females, mean age 71 ± 52 months. In all children, volumetric hemodynamic and blood gas parameters were monitored following initial resuscitation and every 4 h thereafter or whenever a hemodynamic deterioration was suspected. During the cumulative hospital stay, a total of 1050 sets of measurements were done. All parameters were stratified in seven groups according to ICP (group A1 = 0-5 mmHg, group A2 = 6-10 mmHg, group A3 = 11-15 mmHg, group A4 16-20 mmHg, group A5 21-25 mmHg, group A6 26-30 mmHg, group A7 >31 mmHg).

RESULTS

Mean values of jugular oxygen saturation (SJO2), jugular oxygen partial pressure (PJO2), extravascular lung water (EVLWi), pulmonary vascular permeability (PVPi), fluid overload (FO), and cerebral extraction of oxygen (CEO2) vary significantly from A3 (11-15 mmHg) to A4 (16-20 mmHg). They relate to ICP in a four-parameter sigmoidal function (4PS function with: r(2) = 0.90), inflection point of 15 mmHg of ICP, and a maximum curvature point on the left horizontal asymptote at 13 mmHg of ICP.

CONCLUSIONS

Mean values of SJO2, PJO2, EVLWi, PVPi, FO, and CEO2 become pathologic at 15 mmHg of ICP; however, the curve turns steeper at 13 mmHg, possibly a warning level in children for the development of post head trauma secondary insult.

Special considerations in infants and children

Head injury in children is one of the most common causes of death and disability in the US and, increasingly, worldwide. This chapter reviews the causes, patterns, pathophysiology, and treatment of head injury in children across the age spectrum, and compares pediatric head injury to that in adults. Classification of head injury in children can be organized according to severity, pathoanatomic type, or mechanism. Response to injury and repair mechanisms appear to vary at different ages, and these may influence optimal treatment; however, much work is still needed before investigation leads to clearly effective clinical interventions. This is true both for the more severe injuries as well as those at the milder end of the injury spectrum, the latter of which have received increasing attention. In this chapter, neuroassessment tools for each age, newer imaging modalities including magnetic resonance imaging (MRI), and specific pediatric management issues, including intracranial pressure (ICP) monitoring and seizure prophylaxis, are reviewed. Finally, specific head injury patterns and functional outcomes relevant to pediatric patients are discussed. While head injury is common, the number of head-injured children is significantly smaller than the corresponding adult head-injured population. When divided further by specific ages, injury types, and other sources of heterogeneity, properly powered clinical research is likely to require large data sets that will allow for stratification across variables, including age. While much has been learned in the past several decades, further study will be required to determine the best management practices for optimizing recovery in individual pediatric patients. This approach is likely to depend on collaborative international head injury databases that will allow researchers to better understand the nuanced evolution of different types of head injury in patients at each age, and the pathophysiologic, treatment-related, and genetic factors that influence recovery.

Evidence-based assessment of severe pediatric traumatic brain injury and emergent neurocritical care

Pediatric traumatic brain injury accounts for approximately 474,000 emergency department visits, 37,000 hospitalizations, and 3,000 deaths in children 14 years and younger annually in the United States. Acute neurocritical care in children has advanced with specialized pediatric trauma centers and emergency medical services. This article reviews pediatric-specific diagnosis, management, and medical decision making related to the neurocritical care of severe traumatic brain injury.

Carotid artery blood flow decreases after rapid head rotation in piglets

Modification of cerebral perfusion pressure and cerebral blood flow (CBF) are crucial components of the therapies designed to reduce secondary damage after traumatic brain injury (TBI). Previously we documented a robust decrease in CBF after rapid sagittal head rotation in our well-validated animal model of diffuse TBI. Mechanisms responsible for this immediate (<10 min) and sustained (∼24 h) reduction in CBF have not been explored. Because the carotid arteries are a major source of CBF, we hypothesized that blood flow through the carotid arteries (Q) and vessel diameter (D) would decrease after rapid nonimpact head rotation without cervical spine injury. Four-week-old (toddler) female piglets underwent rapid (<20 msec) sagittal head rotation without impact, previously shown to produce diffuse TBI with reductions in CBF. Ultrasonographic images of the bilateral carotid arteries were recorded at baseline (pre-injury), as well as immediately after head rotation and 15, 30, 45, and 60 min after injury. Diameter (D) and waveform velocity (V) were used to calculate blood flow (Q) through the carotid arteries using the equation Q=(0.25)πD(2)V. D, V, and Q were normalized to the pre-injury baseline values to obtain a relative change after injury in right and left carotid arteries. Three-way analysis of variance and post-hoc Tukey-Kramer analyses were used to assess statistical significance of injury, time, and side. The relative change in carotid artery diameter and flow was significantly decreased in injured animals in comparison with uninjured sham controls (p<0.0001 and p=0.0093, respectively) and did not vary with side (p>0.39). The average carotid blood velocity did not differ between sham and injured animals (p=0.91). These data suggest that a reduction in global CBF after rapid sagittal head rotation may be partially mediated by a reduction in carotid artery flow, via vasoconstriction.

Risk factors for mortality in children with abusive head trauma

OBJECTIVE

We sought to identify risk factors for mortality in a large clinical cohort of children with abusive head trauma.

STUDY DESIGN

Bivariate analysis and multivariable logistic regression models identified demographic, physical examination, and radiologic findings associated with in-hospital mortality of children with abusive head trauma at 4 pediatric centers. An initial Glasgow Coma Scale (GCS) ≤ 8 defined severe abusive head trauma. Data are shown as OR (95% CI).

RESULTS

Analysis included 386 children with abusive head trauma. Multivariable analysis showed children with initial GCS either 3 or 4-5 had increased mortality vs children with GCS 12-15 (OR = 57.8; 95% CI, 12.1-277.6 and OR = 15.6; 95% CI, 2.6-95.1, respectively, P < .001). Additionally, retinal hemorrhage (RH), intraparenchymal hemorrhage, and cerebral edema were independently associated with mortality. In the subgroup with severe abusive head trauma and RH (n = 117), cerebral edema and initial GCS of 3 or 4-5 were independently associated with mortality. Chronic subdural hematoma was independently associated with survival.

CONCLUSIONS

Low initial GCS score, RH, intraparenchymal hemorrhage, and cerebral edema are independently associated with mortality in abusive head trauma. Knowledge of these risk factors may enable researchers and clinicians to improve the care of these vulnerable children.

Intracranial pressure-monitoring systems in children with traumatic brain injury: combining therapeutic and diagnostic tools

OBJECTIVE

To compare the correlation of intracranial pressure (ICP) measurement and time to detection of ICP crises (defined as ICP ≥ 20 mm Hg for ≥ 5 mins) between an intraparenchymal (IP) monitor and external ventricular drain (EVD) in children for whom continuous cerebrospinal fluid diversion was used as a therapy for severe traumatic brain injury.

SETTING

Academic, pediatric intensive care unit.

DESIGN

Retrospective review of a prospectively collected pediatric neurotrauma database.

PATIENTS

Children with severe traumatic brain injury (Glasgow Coma Scale score of ≤ 8) who underwent ICP monitoring with both IP and EVD techniques were studied. In cohort 1 (n = 58), hourly ICP measurements were extracted from the medical record; in cohort 2 (n = 4), ICP measurements were collected every minute by an automated data-collection system.

MEASUREMENTS AND MAIN RESULTS

The mean absolute difference in ICP (|N5ICP|N5) and intraclass correlation coefficients were calculated. Timing to detection of ICP crises was analyzed. Data were expressed as mean ± sem. For cohort 1, 7,387 hrs of data were analyzed; 399 hrs (23,940 mins) were analyzed for cohort 2. In cohort 1, the |N5ICP|N5 was 3.10 ± 0.04 mm Hg (intraclass correlation coefficients = 0.98, p < .001). The |N5ICP|N5 in cohort 2 was 3.30 ± 0.05 mm Hg (intraclass correlation coefficients = 0.98, p < .001). In cohort 2, a total of 75 ICP crises were observed. Fifty-five (73%) were detected first by the IP monitor, of which 35 were not identified by the EVD monitor. Time between IP and EVD detection of a crisis was 12.60 ± 2.34 mins.

CONCLUSION

EVD and IP measurements of ICP were highly correlated, although intermittent EVD ICP measurements may fail to identify ICP events when continuously draining cerebrospinal fluid. In institutions that use continuous cerebrospinal fluid diversion as a therapy, a two-monitor system may be valuable for accomplishing monitoring and therapeutic goals.

Head trauma in children, part 2: course and discharge with outcome

To minimize the secondary brain damage, we analyzed the effect of cerebral perfusion pressure-orientated management and tried to find factors of clinical management and biochemical findings that influence clinical, cognitive, and psychosocial outcome. Management at intensive care unit was standardized. A standardized (short form 36 health survey) and nonstandardized split questionnaire explored long-term outcome. Glutamic-oxaloacetic-transaminase, creatine kinase MB or glucose are markers for bad outcome (P < .05). Patients with cerebral perfusion pressure values below the recommended standard for just a single occurrence had significantly worse outcome (P = .0132). Mean arterial pressure, central venous pressure, and heart rate alone do not correlate with outcome. At least 1 occurrence of mean arterial pressure and central venous pressure below the lower limits resulted in a poor outcome (P = .035). Cerebral perfusion pressure-guided therapy seems to prevent further brain damage and results in outcome scores that are comparable to those children with head trauma exhibiting symptoms of mild brain edema.

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.

New concepts in treatment of pediatric traumatic brain injury

Emerging evidence suggests unique age-dependent responses following pediatric traumatic brain injury. The anesthesiologist plays a pivotal role in the acute treatment of the head-injured pediatric patient. This review provides important updates on the pathophysiology, diagnosis, and age-appropriate acute management of infants and children with severe traumatic brain injury. Areas of important clinical and basic science investigations germane to the anesthesiologist, such as the role of anesthetics and apoptosis in the developing brain, are discussed.

Traumatic brain injury in children: recent advances in management

To define and discuss new developments in the field of pediatric traumatic brain injury (TBI). Review of several recent key studies on therapy since publication of the first U.S. traumatic brain injury guidelines in 2003. In addition, we discuss new developments in the use of biomarkers of brain injury in TBI diagnosis and also discuss recent advances in bedside neuromonitoring that may be helpful in the setting of pediatric brain injury. Important new information on optimal cerebral perfusion pressure management, cerebrospinal fluid drainage, decompressive craniectomy, hypothermia, biomarkers of brain injury along with advances in neuromonitoring are presented. The 2003 guidelines have stimulated important new research. This is reshaping bedside care.

ICP and CPP: excellent predictors of long term outcome in severely brain injured children

OBJECTIVE

To determine the predictive powers of intracranial pressure (ICP) and cerebral perfusion pressure (CPP) amongst severely brain injured children.

MATERIALS AND METHODS

ICP and CPP were recorded from thirty-five severely brain injured children who were prospectively recruited after admission to paediatric intensive care. Twenty-five suffered traumatic brain injury (TBI) and ten suffered non-TBI. Peak ICP and minimum CPP recorded for each patient during their admission were related to 5 year Glasgow Outcome Scale outcome. Receiver operator characteristic curves determined that the optimum threshold for unfavourable outcome prediction was >or=40 mmHg for ICP and <or=49 mmHg for CPP. At these thresholds the sensitivity/specificity pairs for the prediction of unfavourable outcome were 33.3/100% and 55.6/100% for ICP and CPP, respectively, amongst patients suffering TBI and were 46.2/100% and 66.2/100% for ICP and CPP, respectively, amongst all patients.

CONCLUSION

ICP and CPP are accurate predictors of unfavourable outcome.

Brain tissue oxygen monitoring in pediatric patients with severe traumatic brain injury

OBJECT

Intracranial pressure (ICP) and cerebral perfusion pressure (CPP) monitoring are fundamental to the management of severe traumatic brain injury (TBI). In adults, brain tissue oxygen monitoring (specifically PO2) and treatment have been shown to be safe additions to conventional neurocritical care and are associated with improved outcome. Brain tissue oxygen monitoring, however, has not been described in pediatric patients with TBI. In this report, the authors present preliminary experience with the use of ICP and PO2 monitoring in this population.

METHODS

Pediatric patients (age <18 years) with severe TBI (Glasgow Coma Scale score <8) admitted to a Level 1 trauma center who underwent ICP and PO2 monitoring were evaluated. Therapy was directed at maintaining ICP below 20 mm Hg and age-appropriate CPP (> or =40 mm Hg). Data obtained in six patients (two girls and four boys ranging in age from 6-16 years) were analyzed. Brain tissue oxygen levels were significantly higher (p < 0.01) at an ICP of less than 20 mm Hg (PO2 29.29 +/- 7.17 mm Hg) than at an ICP of greater than or equal to 20 mm Hg (PO2 22.83 +/- 13.85 mm Hg). Significant differences (p < 0.01) were also measured when CPP was less than 40 mm Hg (PO2 2.53 +/- 7.98 mm Hg) and greater than or equal to 40 mm Hg (PO2 28.97 +/- 7.85 mm Hg).

CONCLUSIONS

Brain tissue oxygen monitoring may be a safe and useful addition to ICP monitoring in the treatment of pediatric patients with severe TBI.

Traumatic brain injury in infants and children: mechanisms of secondary damage and treatment in the intensive care unit

Unfortunately no specific pharmacologic therapies are available for the treatment of TBI in patients. Current investigation of contemporary therapies for the treatment of TBI consists of recycling of previously tested therapies in the era of contemporary neurointensive care. These therapies include hypothermia, decompressive craniectomy, osmotherapy, and controlled hyperventilation. It is hoped that more detailed knowledge regarding the dominant pathophysiologic mechanisms associated with TBI-excitotoxicity, CBF dysregulation, oxidative stress, and programmed cell death-will catapult an efficacious intervention from the laboratory bench to the bedside. This intervention may be a potent agent targeting a single dominant pathway, a broad-spectrum intervention such as hypothermia, or, more likely, a combination of therapies. Meanwhile, practitioners must offer meticulous supportive neurointensive care using clinically proven therapies aimed at minimizing cerebral swelling for the management of pediatric patients who are victims of TBI.

Hypothermia related changes in electrocortical activity at stepwise increase of intracranial pressure in piglets

Recent experimental studies have demonstrated that mild hypothermia can be effective in the control of intracranial hypertension. However, investigations to analyze the effects of hypothermia on changes in brain oxygen metabolism and electrocortical activity caused by increased intracranial pressure (ICP) are lacking. We examined the effects of mild hypothermia on electrocorticogram (ECoG) in combination with measurement of regional cerebral blood flow (CBF) and estimation of brain oxygen metabolism during stepwise increase of ICP. For this purpose thirteen female piglets (14 days old, 4-5 kg b.w.) were anaesthetized and mechanically ventilated. An epidural balloon was gradually inflated in order to increase ICP to 25 mmHg, 35 mmHg and 45 mmHg every 30 minutes at adjusted mean arterial blood pressures (MAP). This procedure resulted in gradual cerebral perfusion pressure (CPP) reduction of about 70%, 50%, and 30% of baseline [baseline CPP: normothermia (NT) 80+/-3 mmHg; hypothermia (HT) 84+/-3 mmHg]. Control animals were maintained in a normothermic state (38.6+/-0.2 degrees C). HT animals were surface cooled and maintained at 31.9+/-0.1 degrees C. ECoG, regional CBF, cerebral oxygen delivery (cDO2) and the cerebral metabolic rate of oxygen (CMRO2) were estimated during the normothermic period, after hypothermic stabilization, and after the gradual CPP reductions. The baseline ECoG showed the typical delta-dominated frequency pattern for isoflurane anaesthesia. At the hypothermic level, a frequency shift was seen from delta activity towards the higher frequencies (theta- and alpha activity) and the total spectral power was significantly reduced (56+/-17% from baseline, p < 0.05). the cortical CBF decreased markedly to 67+/-10% (p < 0.05), whereas the medulla oblongata blood flow increased slightly. During controlled increase of ICP by regional mass expansion from epidural balloon inflation, we found at mild and moderate stages of ICP increase (25 and 35 mmHg) only minimal changes in the ECoG in hypothermic animals compared to the hypothermic baseline, whereas the ECoG in normothermic animals showed a marked decrease in frequency, amplitude and total spectral power. We conclude that mild hypothermia produces an arousal-like ECoG activity with marked frequency shift to alpha activity and a change from high to low voltage activity. Furthermore, the hypothermic brain showed a preserved neuronal function at moderate stages of ICP. Obviously, hypothermia improves the functional tolerance of the brain to impaired oxygen supply.