Simulation of emergency department operations: A comprehensive review of KPIs and operational improvements

Emergency departments (EDs) are one of the main entry points of a hospital, offering non-stop healthcare services to patients with various needs. ED crowding is considered a major international problem. To cope with this problem, operations research techniques have been widely applied to analyse and optimise ED operations. In this regard, two essential aspects are the key performance indicators (KPIs) and improvement options under investigation. This paper structures the scientific literature on ED simulation based on KPIs and improvement options. Apart from a comprehensive discussion of individual KPIs and individual improvement options, studies combining multiple KPIs or multiple improvement options are discussed. In addition, the two aspects are linked by investigating the relationship between KPIs and improvement options. The focus is on simulation research, as this technique is most suitable to capture the randomness and complexity of patient flow through the ED. Because of the importance of efficient ED operations and the general recognition, and worsening, of the crowding problem, the amount of research keeps expanding. Structuring the literature can provide guidance to both researchers and practitioners when deciding on the KPIs and improvement options to consider. In fact, this study is the first to comprehensively analyse the relations between KPIs and improvement options, thereby providing insights into which options have an effect (either positive or negative) on which KPIs according to current literature. Finally, this literature review reveals promising areas for future research into ED crowding.