Time spent with impaired autoregulation is linked with outcome in severe infant/paediatric traumatic brain injury.

Abstract

It could be shown in traumatic brain injury (TBI) in adults that the functional status of cerebrovascular autoregulation (AR), determined by the pressure reactivity index (PRx), correlates to and even predicts outcome. We investigated PRx, cerebral perfusion pressure (CPP) and intracranial pressure (ICP) and their correlation to outcome in severe infant and paediatric TBI. Seventeen patients (range, 1day to 14years) with severe TBI (median GCS at presentation, 4) underwent long-term computerised ICP and mean arterial pressure (MAP) monitoring using dedicated software to determine CPP and PRx and optimal CPP (CPP level where PRx shows best autoregulation) continuously. Outcome was determined at discharge and at follow-up using the Glasgow Outcome Scale. Favourable outcome was reached in eight patients, unfavourable outcome in seven patients. Two patients died. Nine patients underwent decompressive craniectomy to control ICP during Intensive Care Unit treatment. When dichotomised to outcome, no significant difference was found for overall ICP, CPP and PRx. The time with severely impaired AR (PRx>0.2) was significantly longer for patients with unfavourable outcome (64h vs 6h, p=0.001). Continuously impaired AR of ≥24h and age<1year was associated to unfavourable outcome. Children with favourable outcome spent the entire monitoring time at or above the optimal CPP. Integrity of AR has a similar role for outcome after TBI in the paediatric population as in adults. The amount of time spent with deranged AR seems to be associated with outcome; a factor especially critical for infant patients. The results of this preliminary study need to be validated in the future.