1. Standards. There are insufficient data to support a treatment standard for this topic.

2. Guidelines. There are insufficient data to support a treatment guideline for this topic.

3. Options. Intracranial pressure monitoring (ICP) is appropriate in infants and children with severe traumatic brain injury (TBI) (Glasgow Coma [GCS] score ≤8).

   The presence of open fontanels and/or sutures in an infant with severe TBI does not preclude the development of intracranial hypertension or negate the utility of ICP monitoring.

   Intracranial pressure monitoring is not routinely indicated in infants and children with mild or moderate head injury. However, a physician may choose to monitor ICP in certain conscious patients with traumatic mass lesions or in patients for whom serial neurologic examination is precluded by sedation, neuromuscular blockade, or anesthesia.

4. Indications from Adult Guidelines. In the adult guidelines for the management of severe TBI1, there were sufficient data to support a treatment guideline mandating ICP monitoring in patients with severe TBI. Even though pediatric-specific data only support a recommendation for ICP monitoring as a treatment option, no evidence exists to suggest that monitoring is less important in children than adults.

   Monitoring ICP is appropriate in patients with severe head injury with an abnormal admission CT scan. Severe head injury is defined as a GCS score of 3-8 after cardiopulmonary resuscitation. An abnormal CT scan demonstrates hematomas, contusions, cerebral edema, and/or compressed basal cisterns.

   Intracranial pressure monitoring is appropriate for patients with severe head injury and a normal CT if two or more of the following features are noted on admission: motor posturing, systemic hypotension, or age >40 yrs.

   Intracranial pressure monitoring is not routinely indicated in patients with mild or moderate head injury. However, a physician may choose to monitor ICP in certain conscious patients with traumatic mass lesions or for whom serial neurologic examination is precluded by sedation or anesthesia.

Published data and consensus practice since the late 1970s suggest that intensive management protocols may reduce the incidence of secondary brain injury after severe TBI and thus improve survival and outcome2-6. A central feature of such protocols is the monitoring of ICP and medical and/or surgical treatment of intracranial hypertension. Control of ICP within the normal range is intended to maintain adequate cerebral perfusion pressure, oxygenation, and metabolic substrate delivery and to avoid cerebral herniation events. The relative importance of avoiding ICP elevation, per se, and reduced cerebral perfusion pressure, is currently uncertain. However, severe perturbations in either value are likely to be adverse and are commonly associated with each other and with poor outcome2, 5, 7-12. Indications for the treatment of variations in cerebral perfusion pressure are addressed in a separate chapter of these guidelines.

No randomized controlled trial to evaluate the effect on outcome of management of severe TBI with or without ICP monitoring has been conducted in any age group. The obstacles to performing such a study include the ethical concern of not monitoring ICP in control patients and the widely accepted use of ICP monitoring in major pediatric centers involved in TBI research. Although modern, ICP-focused, intensive management protocols have almost unquestionably improved outcomes, these protocols have involved the simultaneous change of a number of other major variables: improved prehospital care, cranial CT imaging for accurate diagnosis of mass lesions, increased use of tracheal intubation and controlled ventilation, more aggressive use of enteral and parenteral nutrition, more active medical management of acute injury, and more widespread availability of formal rehabilitation programs. During this period, ICP monitoring has emerged as an accepted practice without being subjected to a randomized trial. Thus, it is difficult to separate the beneficial or deleterious effects of ICP monitoring, or other efforts to "manage" ICP, from the many other developments in treatment of severe TBI.

We searched Medline and Healthstar from 1966 to 2001 by using the search strategy for this question (see Appendix A) and supplemented the results with literature recommended by peers or identified from reference lists. Of 18 potentially relevant studies, 14 were used as evidence for this question (Table 1).

Of note, many studies in this literature specifically exclude children <3 yrs of age and those with head injury resulting from nonaccidental trauma13.

There are two lines of evidence to support the use of ICP monitoring in severe pediatric TBI:

1. Strong evidence supports the association of intracranial hypertension and poor neurologic outcome.
2. ICP monitoring and aggressive treatment of intracranial hypertension are associated with the best reported clinical outcomes.

Nine studies involving 518 pediatric patients have demonstrated an association between intracranial hypertension and poor neurologic outcome and/or increased mortality rate14-22. These studies, and their individual ICP thresholds associated with poor outcome (generally >20 mm Hg; see Chapter 6), are listed in Table 1.

Monitoring and aggressive ICP-directed therapy have produced the best historical outcomes in the treatment of severe pediatric TBI. Studies that used three different intervention strategies for ICP control have produced similar and convincing reductions in the expected mortality and/or neurologic morbidity rate. These strategies include decompressive craniectomy23, 24, hyperosmolar therapy25, and hyperventilation therapy26. Each of these strategies is based and depends on accurate, continuous monitoring of intracranial pressure.

Two prospective studies of effective control of refractory intracranial hypertension that used decompressive craniectomy have demonstrated improved neurologic outcome23, 24. Cho and colleagues24 performed decompressive craniectomy for medically refractory intracranial hypertension due to abusive head trauma in a cohort of infants and toddlers. They showed improved Children's Outcome Score in the surgical cohort compared with a nearly contemporaneous cohort of nonoperated children from the same institution. Taylor and colleagues23 performed a prospective, randomized clinical trial of decompressive craniectomy for severe TBI in children aged 1-18 yrs. They showed a significantly reduced ICP in the first 48 hrs after randomization in those patients undergoing surgery, compared with those receiving maximal medical management and ventricular drainage alone. Surgical patients also experienced a strong trend toward improvement in Glasgow Outcome Score 6 months after injury, in this relatively small, single-institution, pilot study.

Peterson et al.25 reported a retrospective study on the use of continuous infusion of 3% saline in 68 infants and children with severe TBI and refractory intracranial hypertension. Intracranial pressure was monitored and therapy was titrated to control ICP at <20 mm Hg. Although there was no concurrent control group, only three patients died of uncontrolled ICP, and mortality rate (15%) was lower than expected based on trauma severity score (40%).

Bruce et al.27 studied 85 children with severe TBI by using ICP monitoring and aggressive therapy with hyperventilation and barbiturates to control ICP <20 mm Hg. Again, although there was no concurrent control group, a 9% mortality rate and 87.5% good outcome were achieved.

Although none of these studies achieve class II evidence for long-term outcome, they strongly support the association of ICP monitoring and the effective management of intracranial hypertension with improved outcome. In addition, raised ICP in children may result in secondary brain injury due to alterations in cerebral blood flow physiology26, 28, 29. Therefore, given the low risk of intracranial pressure monitoring (see Chapter 7), these data suggest a strongly favorable risk/benefit ratio for ICP monitoring in severe pediatric TBI.

The issue of who is at risk for intracranial hypertension is less clear for infants and young children than adults with TBI. Shapiro and Marmarou21 reported a retrospective evaluation of ICP monitoring in a case series of 22 children with TBI. They found that 86% of children with a GCS ≤8 had ICP values >20 mm Hg during the course of their monitoring.

Although GCS and neurologic examination remain the standard for the clinical evaluation of patients with TBI, these may be less sensitive in infants and young children30, 31. Certain imaging correlates of intracranial hypertension (such as compressed basal cisterns) are also poorly defined and can be misleading in children21, 32. Combined with a paucity of pediatricspecific studies, this results in limited information about which pediatric TBI patients are at risk for intracranial hypertension and should be monitored. However, given that pediatric head injury patients may suffer late deterioration and death31, monitoring certain patients with moderate TBI (e.g., those undergoing sedation, neuromuscular blockade, or anesthesia for the management of extracranial injuries) may be appropriate.

The clinical evaluation of an infant with TBI may be difficult, and a normal initial cranial CT does not rule out the possibility of intracranial hypertension30-32. The presence of open fontanels and/or sutures does not preclude the development of intracranial hypertension24. Thus, intracranial pressure monitoring can be of significant use in infants suffering from severe traumatic brain injury due to abusive head trauma or other mechanisms.

Key Elements From the Adult Guidelines Relevant to Pediatric TBI

Severely head-injured patients (GCS ≤8) are at high risk for intracranial hypertension10, 33. The combination of severe head injury and an abnormal head CT scan suggests a high likelihood (53-63%) of raised ICP12. However, even with a normal admission CT scan, intracranial hypertension may be present3, 34.

Patients with mild and moderate head injury (GCS 9-15) are less likely to suffer from intracranial hypertension than severely head-injured patients, and therefore the small risk and expense of ICP monitoring may be relatively less justified. Furthermore, serial neurologic examinations are more eloquent in these patients and likely of greater accuracy in monitoring clinically significant changes in neurologic status. However, conscious patients with traumatic mass lesions suggestive of a risk of neurologic deterioration, such as diffuse brain swelling on CT or temporal lobe contusion, may be monitored based on the opinion of the treating physician4, 32. Inability to perform serial neurologic examinations, because of pharmacologic sedation or anesthesia, may also influence a clinician's decision to monitor ICP in an individual patient30, 31.

In adults, the presence of two of three adverse factors (systolic hypotension, unilateral or bilateral motor posturing, age >40) predicted a significant rate of intracranial hypertension despite a normal CT scan. Data collected predominantly in adult patients suggest that detection and treatment of intracranial hypertension may protect cerebral perfusion, avoid cerebral herniation, and improve neurologic outcome5, 10, 32, 33, 35, 36. Thus, the "Guidelines for the Management of [Adult] Severe Head Injury"1 recommend ICP monitoring in adults with an abnormal CT scan or with two or more of these variables.

Clinical signs of raised ICP are generally associated with a change in the level of consciousness and/or cerebral herniation. Level of consciousness is not measurable in severely head-injured (and thus by definition comatose) patients, and herniation comes after severe and often irreversible brain injury has occurred37, 38. Direct, physiologic monitoring is thus the most accurate method of determining ICP38, 39.

Intracranial pressure data allow the management of severe head injury by objective criteria. This is particularly important because many, and perhaps all, medical and surgical measures for the treatment of intracranial hypertension have significant potential adverse consequences40-42. Thus, ICP monitoring allows the judicious use of interventions such as hyperosmolar therapy, sedatives, paralytics, barbiturates, and ventilator management, with a defined end point that is correlated with clinical outcome. This may avoid potentially harmful, overly aggressive treatment.

In adults, a number of important studies suggest that ICP monitoring and intervention for intracranial hypertension may have a significant salutary effect on survival and outcome after severe head injury. Intensive management protocols including ICP monitoring have lowered mortality rates compared with historical controls and compared with centers in other countries not using monitoring techniques2, 32, 43, 44. Eisenberg et al.45 reported that in severely head-injured patients, those in whom ICP could be well controlled with barbiturates had better outcomes than those with refractory intracranial hypertension. Finally, in a small, single-institution study of patients triaged according to the attending neurosurgery call schedule, mortality rate was more than four times higher in nonmonitored than in monitored patients with severe head injury46.

Two lines of evidence support the use of ICP monitoring as a treatment option in severe pediatric TBI. In addition, guideline level support in the adult literature mirrors the pediatric evidence that ICP monitoring is of clinical benefit in severe TBI. Intracranial hypertension may be difficult to diagnose in infants and young children and is associated with decreased survival and poor neurologic outcome. The presence of an open fontanel and/or sutures in an infant with severe TBI does not preclude the development of intracranial hypertension or negate the utility of ICP monitoring. ICP monitoring is not routinely indicated in infants and children with mild or moderate head injury. However, a physician may choose to monitor ICP in certain conscious patients with traumatic mass lesions or in whom serial neurologic examination is precluded by sedation, neuromuscular blockade, or anesthesia.

Definitive evidence of the value of ICP monitoring would require the performance of a prospective, randomized clinical trial of appropriate power. However, it appears unlikely that such a study will ever be carried out. Study of the efficacy of specific, ICP-directed therapies on long-term, age-appropriate, neurologic outcome in infants and children is needed. Further study of the efficacy of ICP-directed therapies in infants and young children with an open fontanel and/or sutures is needed. Similarly, additional studies of ICP monitoring and ICPdirected therapies in infants and young children with abusive head trauma should be conducted.