A 60-year-old man on ICU has severe traumatic brain injury. The team monitors the pressure reactivity index (PRx) as part of multimodal neuromonitoring. PRx is consistently +0.4 (normal <0). What does a positive PRx indicate?ANormal cerebral autoregulationBImpaired cerebral autoregulation - a positive PRx indicates that cerebral blood volume (and therefore ICP) passively follows changes in arterial blood pressure, meaning the cerebral vasculature has lost its ability to maintain constant cerebral blood flow across a range of CPP; this is associated with worse outcomesCThe ICP monitor is faultyDThe PRx is clinically irrelevantENegative PRx indicates impaired autoregulationCheck my answer