The emergency department "carousel": an ethnographically-derived model of the dynamics of patient flow.

Emergency department (ED) overcrowding reduces efficiency and increases the risk of medical error leading to adverse events. Technical solutions and models have done little to redress this. A full year's worth of ethnographic observations of patient flow were undertaken, which involved making hand-written field-notes of the communication and activities of emergency clinicians (doctors and nurses), in two EDs in Sydney, Australia.