Optimal Cerebral Perfusion Pressure Assessed with a Multi-Window Weighted Approach Adapted for Prospective Use: A Validation Study

BACKGROUND: Pressure reactivity index (PRx)-cerebral perfusion pressure (CPP) relationships over a given time period can be used to detect a value of CPP at which PRx shows the best autoregulation (optimal CPP, or CPPopt). Algorithms for continuous assessment of CPPopt in traumatic brain injury (TBI) patients reached the desired high yield with a multi-window approach (CPPopt_MA). However, the calculations were tested on retrospective manually cleaned datasets. Moreover, CPPopt false-positive values can be generated from non-physiological variations of intracranial pressure (ICP) and arterial blood pressure (ABP). Therefore, the algorithm robustness was improved, making it suitable for prospective bedside application (COGiTATE trial).OBJECTIVE: To validate the CPPopt revised algorithm in a large single-centre retrospective cohort of TBI patients.METHODS: 840 TBI patients were included. CPPopt yield, stability and ability to discriminate outcome groups were compared to CPPopt_MA and the Brain Trauma Foundation (BTF) guideline reference.RESULTS: CPPopt yield was lower than CPPopt_MA yield (85% and 90%, p < 0.001), but, importantly, with increased stability (p < 0.0001). The ∆(CPP-CPPopt) could distinguish the mortality and survival outcome (t = -6.7, p < 0.0001) with a statistical significance higher than the ∆CPP calculated with the guideline reference (CPP-60) (t = -4.5, p < 0.0001).CONCLUSION: This study validates, on a large cohort of patients, the new algorithm proposed for prospective use of CPPopt as a CPP target at bedside.