Using closed malpractice claims from a previously described database, this study discovered significant patient injury associated with monitored anesthesia care (MAC) and a liability profile similar to that of general anesthesia. Investigators performed a detailed analysis of more than 120 MAC claims, compared them with those of general and regional anesthesia, and report on the claim characteristics. MAC claims involved older and more ill patients, with respiratory depression being the most frequent occurrence leading to patient injuries. The authors conclude that more than half of the claims would be preventable with improved monitoring strategies.