Relationship of intracranial pressure and cerebral perfusion pressure with outcome in young children after severe traumatic brain injury.

Traumatic brain injury (TBI) is the most common cause of death for children less than 18 years of age. Current standards of care for children with severe TBI include monitoring of intracranial pressure (ICP), and goal-directed therapies to minimize ICP and optimize cerebral perfusion pressure (CPP; the mathematical difference between the mean arterial pressure and ICP). Current guidelines for ICP and CPP thresholds suggest that age-based thresholds should be adopted, but few studies have included the youngest children affected by TBI (those <2 years of age). We performed a retrospective analysis of our pediatric neurotrauma database to determine if ICP and CPP thresholds associated with favorable neurological outcome could be determined, or if the number of episodic alterations in the parameters (ICP >15 or >20 mm Hg; CPP <40 mm Hg, <45 mm Hg or <50 mm Hg) was different between children with favorable and unfavorable outcomes (based on dichotomous Glasgow Outcome Scale score at 6 months after TBI). Data from 22 children (of whom 81% had suffered from inflicted childhood neurotrauma) were analyzed in the first 7 days. Children with unfavorable outcome had more hourly readings of CPP of <45 mm Hg compared to children with favorable outcome [median (25-75%): 2 (1-31) vs. 0 (0-2); p <0.05]. There was no difference between the number of hourly readings of ICP of >20 mm Hg between the outcome groups [median (25-75%): favorable 0 (0-1) vs. unfavorable 1 (0-4); p = 0.17]. To our knowledge, this is the first exploratory report to test if CPP and ICP thresholds can be established for this young population of children after TBI, and it suggests a CPP target threshold of 45 mm Hg. Despite good ICP control in this population, there was still a 50% incidence of unfavorable outcome, suggesting that there may be unique physiologic parameters that need to be targeted in infants with severe TBI. A prospective study is needed to fully determine what goals should be targeted for this vulnerable population.