Because some 60,000 people undergo surgery daily in the U.S., and the numbers continue to climb, quantifying the risk is essential. It hasn’t helped that the term “POCD” is vague. “We’re talking about things that happen immediately after operations, like delirium, to things that happen perhaps a decade after an operation like dementia or Alzheimer’s,” notes Roderic Eckenhoff, an anesthesiologist and researcher at the University of Pennsylvania.