Inflicted Childhood Neurotrauma: New Insight into The Detection, Pathobiology, Prevention, and Treatment of Our Youngest Patients with Traumatic Brain Injury

Successful enteral nutritional support in the neurocritical care unit

PURPOSE

Adequate caloric intake is associated with improved outcome in neurocritical illness, but factors influencing the provision of enteral nutrition (EN) have not been systematically evaluated. The primary goal of the study was to determine the EN intake of neurosurgical intensive care unit (ICU) patients within the first week of illness and investigate the factors contributing to achieving caloric goals.

METHODS

A retrospective cohort of adult patients admitted to the neurosurgery service (NS) during August 2005-August 2006 were randomly selected and stratified into three groups based on their ICU-admission Glasgow Coma Scale Score (GCS) (GCS > 11, GCS 8-11, GCS 4-7). Daily EN intake, GCS, and other clinical data were collected.

RESULTS

A total of 71 patients were included (GCS > 11 = 23, GCS 8-11 = 23, GCS 4-7 = 25). Admitting diagnoses included traumatic brain injury (TBI) (32%), subarachnoid hemorrhage (SAH) (32%), and intracerebral hemorrhage (17%). The overall in-hospital mortality was 23.9%. Overall, the maximum daily mean calories provided was 1,100 kcal (mean of 55% of caloric goal on hospital day 6). The median time to feeding was approximately 3 days in each group. GCS did not appear to significantly affect the mean % of caloric goal administered in patients with a minimum daily GCS < or = 11 (P = 0.053). Multivariate analysis revealed that clinical care factors, such as time to EN orders and enteral access confirmation, were significant impediments to EN provision (P = 0.001).

CONCLUSION

System-based clinical care factors appear to have great impact on the successful provision of EN in the first week of neurocritical illness.

The significance of altered temperature after traumatic brain injury: an analysis of investigations in experimental and human studies: part 2

Raised body temperature is a common occurrence after severe traumatic brain injury (TBI). It is widely accepted that experimental evidence points to a harmful effect of raised temperature both during and after TBI. Consequently, the policy of many neurocritical care units is to implement therapies for body temperature control. This article reviews the evidence that links spontaneous temperature changes with worsened outcome after experimentally-induced and human brain trauma. The current evidence-base and rationale for treatment of raised temperature after TBI is presented with discussion positing areas for further work to explore the notion that raised temperature may not be deleterious in all neurosurgical patients.

Intracranial Pressure Monitoring in Severe Isolated Pediatric Blunt Head Trauma

Very little research regarding standard treatments for pediatric traumatic brain injury (PTBI) exists. The objective of this study was to examine the use of intracranial pressure (ICP) monitoring devices in PTBI and to determine if its use was associated with any outcome benefit. Data were collected from the Trauma Registry over an 11-year period (1996–2006) on all blunt trauma pediatric patients (age < 14 years) with an initial Glasgow Coma Scale score ≤ 8. Data collected included: demographics, admission Glasgow Coma Scale score, mechanism of injury, Injury Severity Score, Abbreviated Injury Score, and use of an ICP monitor. Outcome measures included: mortality, complications, discharge location, and capacity. Thirty-three (25%) of 129 blunt PTBI patients had ICP monitors placed. Patients with monitors were more severely injured overall (Injury Severity Score: 25 vs 18, P = 0.001) and had more severe head injury (81% head Abbreviated Injury Score > 3 vs 55%, P = 0.01) than patients without monitors. However, there was no difference in mortality (28% vs 35%, P = 0.52), discharge location (P = 0.10), and discharge capacity (P = 0.84). After multivariable analysis to adjust for the differences between the two study groups, the use of ICP monitor provided no survival benefit (adjusted odds ratio: 1.1; 95% confidence interval [CI]: 0.3–4.1; adjusted P value = 0.85). The use of ICP monitor was, however, independently associated with a higher risk of developing extracranial complications (adjusted odds ratio: 4.3; 95% CI: 1.2–16.4; adjusted P value = 0.025). In conclusion, the use of ICP monitors in pediatric patients with severe isolated head injury provided no survival benefit and was associated with an increased risk of complications.

Classification of traumatic brain injury for targeted therapies

The heterogeneity of traumatic brain injury (TBI) is considered one of the most significant barriers to finding effective therapeutic interventions. In October, 2007, the National Institute of Neurological Disorders and Stroke, with support from the Brain Injury Association of America, the Defense and Veterans Brain Injury Center, and the National Institute of Disability and Rehabilitation Research, convened a workshop to outline the steps needed to develop a reliable, efficient and valid classification system for TBI that could be used to link specific patterns of brain and neurovascular injury with appropriate therapeutic interventions. Currently, the Glasgow Coma Scale (GCS) is the primary selection criterion for inclusion in most TBI clinical trials. While the GCS is extremely useful in the clinical management and prognosis of TBI, it does not provide specific information about the pathophysiologic mechanisms which are responsible for neurological deficits and targeted by interventions. On the premise that brain injuries with similar pathoanatomic features are likely to share common pathophysiologic mechanisms, participants proposed that a new, multidimensional classification system should be developed for TBI clinical trials. It was agreed that preclinical models were vital in establishing pathophysiologic mechanisms relevant to specific pathoanatomic types of TBI and verifying that a given therapeutic approach improves outcome in these targeted TBI types. In a clinical trial, patients with the targeted pathoanatomic injury type would be selected using an initial diagnostic entry criterion, including their severity of injury. Coexisting brain injury types would be identified and multivariate prognostic modeling used for refinement of inclusion/exclusion criteria and patient stratification. Outcome assessment would utilize endpoints relevant to the targeted injury type. Advantages and disadvantages of currently available diagnostic, monitoring, and assessment tools were discussed. Recommendations were made for enhancing the utility of available or emerging tools in order to facilitate implementation of a pathoanatomic classification approach for clinical trials.

Cerebral apoptosis in severe traumatic brain injury patients: an in vitro, in vivo, and postmortem study

One of the most important recent observations in traumatic brain injury (TBI) relates to the potential role of apoptosis in secondary brain injury. We aimed to analyze the presence of apoptosis and the expression of apoptosis-related proteins in brain samples from patients with TBI. We also tried to find any association between the in situ results and the in vitro observations in a neuronal model of induced-apoptosis. Brain tissue from the pericontusional zone (PCZ) of patients with traumatic contusions and from post-mortem samples was analyzed. Immunohistochemical analyses of apoptosis-related proteins and the terminal deoxynucleotide transferase-mediated nick end labeling (TUNEL) method to determine the presence of apoptotic cells were performed. Apoptotic rates on neuronal cells induced by jugular bulb vein sera was determined by flow cytometry. TUNEL-positive cells were detected in all PCZ of traumatic contusions and in most of PCZ in post-mortem specimens (none in control; p = 0.026). In vivo samples showed higher expression of antiapoptotic proteins Bcl-2 (p = 0.027) and Bcl-XL (p = 0.014) than post-mortem samples. In autopsies, the expression of Fas and Bim (p < 0.05) were higher in PCZ than in the zone distal from the contusion. In vitro studies showed that apoptotic rate was an independent factor associated with mortality at 6 months (p = 0.014). In the receiving operator curve (ROC) curve, a cut-off point of 66.5% showed a sensitivity of 89.5% and specificity of 66.7% in the prediction of patients' death. Cerebral apoptosis is a prominent form of cell death in the PCZ of human traumatic cerebral contusions, and high rates of in vitro apoptosis are associated with a poorer prognosis after TBI.

Brain tissue oxygen tension is more indicative of oxygen diffusion than oxygen delivery and metabolism in patients with traumatic brain injury

OBJECTIVES

Despite the growing clinical use of brain tissue oxygen monitoring, the specific determinants of low brain tissue oxygen tension (P(bt)O2) following severe traumatic brain injury (TBI) remain poorly defined. The objective of this study was to evaluate whether P(bt)O2 more closely reflects variables related to cerebral oxygen diffusion or reflects cerebral oxygen delivery and metabolism.

DESIGN

Prospective observational study.

SETTING

Level I trauma center.

PATIENTS

Fourteen TBI patients with advanced neuromonitoring underwent an oxygen challenge (increase in FiO2 to 1.0) to assess tissue oxygen reactivity, pressure challenge (increase in mean arterial pressure) to assess autoregulation, and CO2 challenge (hyperventilation) to assess cerebral vasoreactivity.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

P(bt)O2 was measured directly with a parenchymal probe in the least-injured hemisphere. Local cerebral blood flow (CBF) was measured with a parenchymal thermal diffusion probe. Cerebral venous blood gases were drawn from a jugular bulb venous catheter. We performed 119 measurements of PaO2, arterial oxygen content (CaO2), jugular bulb venous oxygen tension (PVO2), venous oxygen content (CVO2), arteriovenous oxygen content difference (AVDO2), and local cerebral metabolic rate of oxygen (locCMRO2). In multivariable analysis adjusting for various variables of cerebral oxygen delivery and metabolism, the only statistically significant relationship was that between P(bt)O2 and the product of CBF and cerebral arteriovenous oxygen tension difference (AVTO2), suggesting a strong association between brain tissue oxygen tension and diffusion of dissolved plasma oxygen across the blood-brain barrier.

CONCLUSIONS

Measurements of P(bt)O2 represent the product of CBF and the cerebral AVTO2 rather than a direct measurement of total oxygen delivery or cerebral oxygen metabolism. This improved understanding of the cerebral physiology of P(bt)O2 should enhance the clinical utility of brain tissue oxygen monitoring in patients with TBI.

Shaken baby syndrome and a baby's cry

The aim of this study was to investigate the relationship between crying of an infant and inflicted head injury by shaking and/or impact. During the period between January 1, 1997 and December 31, 2003, 26 cases of shaken baby syndrome (SBS) were identified in Estonia. The incidence of SBS was 28.7 per 100,000 children under 1 year of age during the whole study period. In this group there were four children from twin pairs: two twin boys and a girl from a twin pair and a boy from another twin pair. This represents 15.4% of the 26 cases. Twins in Estonia represent 2.12% of infant births. The mean age on admission was 3.9 months. According to outpatient records almost all parents (88.5%) in the study group (23/26) had contacted their family physicians and other specialists because of excessive crying or irritability of the baby prior to the admission to the hospital with SBS or death. We found that the time curve of crying was similar to the curve of highest incidence of cases of SBS except the crying curve began earlier. CONCLUSION. Our data confirm that the families with twins are at additional risk for SBS and parent's complaints of excessive crying of their infants should be taken as signal that parents need to be carefully counselled.

Hypothermia treatment for traumatic brain injury: a systematic review and meta-analysis

In this study, we conducted an updated meta-analysis of the effects of hypothermia therapy on mortality, favorable neurologic outcome, and associated adverse effects in adults with traumatic brain injury (TBI) for use by Brain Trauma Foundation (BTF)/American Association of Neurological Surgeons (AANS) task force to develop evidence-based treatment guidelines. Our data sources relied on handsearches of four previous good-quality systematic reviews, which all conducted electronic searches of primarily MEDLINE (OVID), EMBASE, and Cochrane Library. An independent, supplemental electronic search of MEDLINE was undertaken as well (last searched June 2007). Only English-language publications of randomized controlled trials of therapeutic hypothermia in adults with TBI were selected for analysis. Two reviewers independently abstracted data on trial design, patient population, hypothermia and cointervention protocols, patient outcomes, and aspects of methodological quality. Pooled relative risks (RR) and associated 95% confidence intervals (CIs) were calculated for each outcome using random-effects models. In the current study, only 13 trials met eligibility criteria, with a total of 1339 randomized patients. Sensitivity analyses revealed that outcomes were influenced by variations in methodological quality. Consequently, main analyses were conducted based on eight trials that demonstrated the lowest potential for bias (n = 781). Reductions in risk of mortality were greatest (RR 0.51; 95% CI 0.33, 0.79) and favorable neurologic outcomes much more common (RR 1.91; 95% CI 1.28, 2.85) when hypothermia was maintained for more than 48 h. However, this evidence comes with the suggestion that the potential benefits of hypothermia may likely be offset by a significant increase in risk of pneumonia (RR 2.37; 95% CI 1.37, 4.10). In sum, the present study's updated meta-analysis supports previous findings that hypothermic therapy constitutes a beneficial treatment of TBI in specific circumstances. Accordingly, the BTF/AANS guidelines task force has issued a Level III recommendation for optional and cautious use of hypothermia for adults with TBI.

Update on shaken baby syndrome: ophthalmology

PURPOSE OF REVIEW

Shaken baby syndrome is a common problem with a high morbidity and mortality. Ophthalmologists help manage this condition and therefore must keep abreast of current advances.

RECENT FINDINGS

Clinical updates include the discovery that retinal folds and traumatic retinoschisis can very rarely occur after crush head injury, but remain specific for shaken baby syndrome in other scenarios. Pathology updates include new studies on orbital histology and woodpecker anatomy that suggest the retinal and optic nerve hemorrhages in shaken baby syndrome are caused by shaking itself rather than secondary to intracranial pathology. Regarding this shaking injury, some primary prevention strategies have proven surprisingly effective. In the near future, serum biomarkers may be used as a screening tool for inflicted neurotrauma. Animal models such as the neonatal pig and computer models using finite element analysis are promising experimental techniques for studying shaken baby syndrome. Finally, child abuse recently became an accredited subspecialty of pediatrics, which will lead to further advances in patient care, education, research and prevention.

SUMMARY

Ophthalmologists play a key role in the diagnosis of shaken baby syndrome. In addition, they are in a unique position to study ophthalmic aspects of the syndrome, which in turn furthers the overall understanding of this devastating condition.