Ten (+1) lessons from conducting a mass casualty in situ simulation exercise in a Canadian academic hospital setting.

Providing care in a twenty-first century urban emergency department (ED) and trauma center is a complex high-pressure practice environment. The pressure is intensified during patient surge scenarios commonly seen during mass casualty incidents, such that response must be practiced regularly. Beyond clinical mastery of individual patient trauma care, a coordinated system-level response is essential to optimize patient care during these relatively infrequent events.