What is the optimal cerebral perfusion pressure in children suffering from traumatic coma?

Early cerebral perfusion pressure augmentation with phenylephrine after traumatic brain injury may be neuroprotective in a pediatric swine model

OBJECTIVE

Cerebral perfusion pressure<40 mm Hg following pediatric traumatic brain injury has been associated with increased mortality independent of age, and current guidelines recommend maintaining cerebral perfusion pressure between 40 mm Hg-60 mm Hg. Although adult traumatic brain injury studies have observed an increased risk of complications associated with targeting a cerebral perfusion pressure>70, we hypothesize that targeting a cerebral perfusion pressure of 70 mm Hg with the use of phenylephrine early after injury in the immature brain will be neuroprotective.

DESIGN

Animals were randomly assigned to injury with a cerebral perfusion pressure of 70 mm Hg or 40 mm Hg. Diffuse traumatic brain injury was produced by a single rapid rotation of the head in the axial plane. Cerebral microdialysis, brain tissue oxygen, intracranial pressure, and cerebral blood flow were measured 30 min-6 hrs postinjury. One hour after injury, cerebral perfusion pressure was manipulated with the vasoconstrictor phenylephrine. Animals were euthanized 6 hrs posttraumatic brain injury, brains fixed, and stained to assess regions of cell injury and axonal dysfunction.

SETTING

University center.

SUBJECT

Twenty-one 4-wk-old female swine.

MEASUREMENTS AND MAIN RESULTS

Augmentation of cerebral perfusion pressure to 70 mm Hg resulted in no change in axonal dysfunction, but significantly smaller cell injury volumes at 6 hrs postinjury compared to cerebral perfusion pressure 40 (1.1% vs. 7.4%, p<.05). Microdialysis lactate/pyruvate ratios were improved at cerebral perfusion pressure 70 compared to cerebral perfusion pressure 40. Cerebral blood flow was higher in the cerebral perfusion pressure 70 group but did not reach statistical significance. Phenylephrine was well tolerated and there were no observed increases in serum lactate or intracranial pressure in either group.

CONCLUSIONS

Targeting a cerebral perfusion pressure of 70 mm Hg resulted in a greater reduction in metabolic crisis and cell injury volumes compared to a cerebral perfusion pressure of 40 mm Hg in an immature swine model. Early aggressive cerebral perfusion pressure augmentation to a cerebral perfusion pressure of 70 mm Hg in pediatric traumatic brain injury before severe intracranial hypertension has the potential to be neuroprotective, and further investigations are needed.

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.

Severe traumatic brain injury in children--a single center experience regarding therapy and long-term outcome

OBJECT

The impact of intracranial pressure (ICP), decompressive craniectomy (DC), extent of ICP therapy, and extracranial complications on long-term outcome in a single-center pediatric patient population with severe traumatic brain injury (TBI) is examined.

METHODS

Data of pediatric (≤16 years) TBI patients were retrospectively reviewed using a prospectively acquired database on neurosurgical interventions between April 1996 and March 2007 at the Charité Berlin. The patients' records, neuroimages, admission Glasgow Coma Scale (GCS) score, the time to craniectomy for hematoma evacuation/DC, and the extent of ICP therapy were reviewed. Twelve-month and long-term outcome was evaluated (Glasgow Outcome Scale).

RESULTS

Fifty-three pediatric TBI patients [mean age 8.41 (0-16) years] were studied. Patients were categorized into two groups, with DC (n = 14) and without DC (n = 39). DC was performed 3 ± 3.98 median, quartiles 2 (0-3.75) days post-trauma. In the majority of children (n = 9; 64%), surgical decompression was performed early within 2 days post-trauma. (0.8 ± 0.9 days). The DC group tended to be older (median age 12 vs. 7 years, p = 0.052), had a lower GCS (3 vs. 6.5, p < 0.01), and had a 3-fold longer stay on the ICU (20 vs. 6.5 days, p < 0.03) compared to the conservatively treated group. Mean follow-up duration (n = 30) was 5.2 ± 2.4 years (range 1-10.5). At the most recent follow-up examination, 92% of survivors had returned to school.

CONCLUSION

Though initial GCS was worse in pediatric TBI patients who underwent decompressive craniectomy compared to the conservatively treated patients, long-term outcome was comparable. In children, decompressive craniectomy might be favored early in the management of uncontrollable ICP.

Are head injury guidelines changing the outcome of head injured children? A regional investigation

BACKGROUND

Secondary pathophysiological CPP insult is related to outcome after head injury, and improved management would be expected to reduce secondary brain insult. Paediatric head injury management guidelines have been published in recent years, by SIGN (2000), RCPCH (2001), NICE (June 2003), and jointly by Critical/Intensive Care Societies (C/ICS July 2003). We investigated whether outcome of children's head injury (and total burden of secondary CPP insult) has changed (1) annually; (2) before and after the introduction of any HI guidelines, and (3) following other service changes.

METHODS

Seventy-six children (aged 1-14 years with severe HI) were admitted to the Edinburgh Regional Head Injury Service between 1989 and 2006, and dichotomised at various time points and compared in terms of: demographic factors, intracranial pressure (ICP), cerebral perfusion pressure (CPP) insults [e.g. age-banded pressure-time index (PTI)], and Glasgow Outcome Scale (GOS) score (assessed at 6 months post injury).

FINDINGS

When dichotomised around the SIGN guidelines, there were no statistically significant differences between the two group's demography or in primary brain injury, but the outcomes were different (p = 0.03), with 6 vs 4 GOS1 (died), 2 vs 4 GOS3 (severely disabled), 5 vs 16 GOS4 (moderately disabled) and 23 vs 14 GOS5 (good recovery), when comparing before and after year 2000. GOS4 was significantly different (chi-square = 7.99, p < 0.007). There was a (non-significant) trend for the later years to have longer insult durations of ICP, hypertension, CPP, hypoxia, pyrexia, tachycardia and bradycardia, greater PTI for both CPP and ICP, and more CPP insults (p = 0.003). There was, however, significantly less CPP insult (p = 0.030) after the introduction of the more management-oriented C/ICS guidelines.

CONCLUSIONS

The most recent paediatric HI guidelines appear to have reduced the burden of secondary insult, but more time is required to determine if this will be reflected in improved outcomes.

Management of critically ill children with traumatic brain injury

The management of critically ill children with traumatic brain injury (TBI) requires a precise assessment of the brain lesions but also of potentially associated extra-cranial injuries. Children with severe TBI should be treated in a pediatric trauma center, if possible. Initial assessment relies mainly upon clinical examination, trans-cranial Doppler ultrasonography and body CT scan. Neurosurgical operations are rarely necessary in these patients, except in the case of a compressive subdural or epidural hematoma. On the other hand, one of the major goals of resuscitation in these children is aimed at protecting against secondary brain insults (SBI). SBI are mainly because of systemic hypotension, hypoxia, hypercarbia, anemia and hyperglycemia. Cerebral perfusion pressure (CPP = mean arterial blood pressure - intracranial pressure: ICP) should be monitored and optimized as soon as possible, taking into account age-related differences in optimal CPP goals. Different general maneuvers must be applied in these patients early during their treatment (control of fever, avoidance of jugular venous outflow obstruction, maintenance of adequate arterial oxygenation, normocarbia, sedation-analgesia and normovolemia). In the case of increased ICP and/or decreased CPP, first-tier ICP-specific treatments may be implemented, including cerebrospinal fluid drainage, if possible, osmotic therapy and moderate hyperventilation. In the case of refractory intracranial hypertension, second-tier therapy (profound hyperventilation with P(a)CO(2) < 35 mmHg, high-dose barbiturates, moderate hypothermia, decompressive craniectomy) may be introduced, after a new cerebral CT scan.

Measurement of intracranial pressure in children: a critical review of current methods

Assessment of intracranial pressure (ICP) is essential in the management of acute intracranial catastrophe to limit or actively reduce ICP. This article provides background information and reviews the current literature on methods of measuring ICP in children. Indications for ICP measurement are described for children with traumatic brain injury, shunt insertion or malfunction, arachnoid cyst, craniosynostosis, and prematurity. Various methods of ICP monitoring are detailed: non-invasive, indirect (lumbar puncture, visual-evoked potentials, fontanelle compression, and optic nerve sheath), and direct assessment (ventricular cannulation, and epidural, subdural, and intraparenchymal devices). Normal levels of ICP will depend on the age and position of the child during monitoring. This article provides clinical and research-based evidence in this area where there is currently limited guidance.

[Decompressive craniectomy in children and adolescents with head injury: analysis of seven cases]

INTRODUCTION

Decompressive craniectomy (DC) is a surgical technique used to treat patients with elevated intracranial pressure often found in head injury. Its indication remains a controversial issue in the pediatric population.

OBJECTIVE

To report seven cases managed with this technique.

METHOD

Retrospective study of seven patients, aged from 2 to 17 years, treated with unilateral DC due to increased intracranial pressure (ICP) as a consequence of head injury. All patients had ICP monitored post operatively and the DC classified as ultra-early (<6h), early (6-12h) or late (>24h) according to the time of its application. The minimum follow-up was six months.

RESULTS

Patients were evaluated with CT scans and clinical exams, and graded according the Glasgow Outcome Scale (GOS). Three patients deceased (GOS1), one was in vegetative state (GOS2), two recovered but still requiring nursing care (GOS3 and 4), and one had a full recovery (GOS5) at hospital discharge. After six months the GOS2 and a GOS3 patients achieved full recovery (GOS5). Subdural collection (2), hydrocephalus (1) and superficial infection (1) occurred as complication. Two patients had autologous cranioplasty and the other two heterologous cranioplasty.

CONCLUSION

Decompressive craniectomy remains a feasible treatment method to lower the ICP, but is not safe from complications. A multicentric study should be done for appropriate protocol treatment of pediatric patients.

Controversies in the care of children with acute brain injury

Care of children with acute brain injury is evolving from mere observation to active intervention that requires intensive care units focused on the nervous system primarily and other organs secondarily. The physical examination supplemented by neuroimaging, invasive monitoring, and an improved understanding of the mechanisms of injury allows for the development of rational therapies. This paper reviews common bedside controversies in care, including initial assessments and outcomes, as well as the prevention of secondary injury through the maintenance of brain oxygen and energy and the treatment of cerebral edema. The advantages and disadvantages of frequently utilized techniques are identified.