The document defines a sentinel event as an unexpected occurrence involving death or serious physical or psychological injury or risk thereof. It then classifies different types of sentinel events such as unanticipated death, major permanent loss of function, wrong surgery/site/person, and nosocomial infections resulting in unanticipated death or injury. The document explains that when a sentinel event occurs, a response team must conduct a root cause analysis (RCA) to determine the underlying causes. It outlines the five steps of an RCA: defining the problem, understanding what happened, determining the root cause, identifying effective solutions, and following up. Tools like 5 Whys and fishbone diagrams can be used to help uncover root causes. The