Survey in expert clinicians on the validity of automated calculation of optimal cerebral perfusion pressure

BACKGROUND: Optimal cerebral perfusion pressure (CPPopt) targeting in traumatic brain injury (TBI) patients constitutes an active and controversial area of research. It has been suggested that an autoregulation guided CPP therapy may improve TBI outcome. Prerequisites of a CPPopt intervention study would be objective criteria for the CPPopt detection. This study compared the agreement between automated and visual CPPopt detection. METHODS: Twenty-five clinicians from 18 centers worldwide, familiar with brain monitoring and using dedicated software, reviewed ten 4-hour CPPopt screenshots at 48 hours after ictus in selected TBI patients. Each screenshot displayed the trends of cerebral perfusion pressure (CPP), intracranial pressure (ICP), cerebrovascular pressure reactivity (PRx) as well as the "CPP-optimal" curve and its associated value (automated CPPopt). The main objective was to evaluate the agreement between expert clinicians as well as the agreement between the clinicians and automated CPPopt. RESULTS : Twenty-two clinicians responded to our call (88%). Three screenshots were judged as "CPPopt not determinable" by > 45% of the clinicians. For the whole group, the consensus between automated CPPopt and clinicians' visual CPPopt was high. Three clinicians were identified as outliers. All clinicians recommended to modify CPP when patients differed >+/- 5 mmHg from their CPPopt. The inter-observer consensus was highest in cases with current CPP below the optimal value. CONCLUSIONS: The overall agreement between automated CPPopt and visual CPPopt identified by autoregulation experts was high, except for those cases when the curve was deemed by the clinicians not reliable enough to yield a trustworthy CPPopt.