Complex sentence: Physicians in training (interns and residents), foreign medical graduates and sometimes nurses also staffed the ED. Emergency medicine was born as a specialty in order to fill the time commitment required by physicians on staff to work in the increasingly chaotic EDs of the time.
Split into simpler sentences: Physicians in training (interns and residents), foreign medical graduates and sometimes nurses also staffed the Emergency Department (ED). EM was born as a specialty in order to fill the time commitment required by physicians on staff to work in the increasingly chaotic emergency departments (EDs) of the time.