Abstract
BACKGROUND: Paediatric traumatic brain injury (TBI) is a heterogeneous condition with age-dependent differences in systemic and cerebral physiology, making cerebral perfusion pressure (CPP) challenging to target. Monitoring cerebral autoregulation using the pressure reactivity index (PRx) and deriving an autoregulatory optimal CPP (CPPopt) may personalize treatment, but evidence in children remains limited. In this multicentre paediatric TBI study, we aimed to explore and visualize PRx and CPPopt in relation to outcome. METHODS: In this secondary analysis of the prospective, multicentre study (STARSHIP), 98 paediatric TBI patients (1-16 years) from 10 paediatric intensive care units, in the UK, between 2018 and 2023, with high-frequency physiological data and 12-month GOS-E Peds outcomes, not treated with decompressive craniectomy, were included. Intracranial pressure (ICP), PRx, CPP, and ΔCPPopt were correlated with outcome using insult intensity/duration heatmaps across the full monitoring period. Two-variable heatmaps incorporating PRx were also used to assess how autoregulation modified the relationship between ICP, CPP, and ΔCPPopt with outcome. RESULTS: There was a transition from favourable to unfavourable outcome when PRx exceeded + 0.00 for longer episodes. Furthermore, there was a transition towards worse outcome when CPP went below 40 mmHg and above 100 mmHg for sustained durations. For ΔCPPopt, the transition towards poor prognosis occurred for values below - 20 mmHg, but positive ΔCPPopt was tolerated. In the two-variable heatmaps, PRx above + 0.50 together with ICP above 20 mmHg, CPP below 60 mmHg, or negative ΔCPPopt were particularly associated with unfavourable outcome. CONCLUSIONS: This novel study visualized the safe and dangerous intervals for PRx and CPPopt as well as the interaction effect between the autoregulatory status and ICP, CPP, and ΔCPPopt in relation to outcome in paediatric TBI. Future prospective trials are needed to evaluate the safety, feasibility, and efficacy of PRx/CPPopt guided management.