Brain Injury in Postoperative Delirium: Lessons from Neurofilament Light

Although the earliest descriptions of delirium date back to 500 BC, it was the English doctor Philip Barrough who first reported in 1583 a “loss of memory and reasoning power” after the resolution of delirium.¹  Modern population-based studies have supported this observation by demonstrating an association between delirium and subsequent accelerated cognitive decline.²  This begs a fundamental question: is delirium causative of cognitive impairment, or is it a symptom of a “vulnerable” brain that was already in decline? Proving causation in this area is difficult but nonetheless extremely important to the study of delirium prevention. One tool to help us prove causation is the demonstration of neuropathology in delirium: if people incur greater brain damage during an episode of delirium, this would provide a pathophysiological connection between delirium and greater subsequent cognitive decline. In this issue of Anesthesiology, Khalifa et al.³  assess the relationship between a...