How Do Missing Patients Aggravate Emergency Department Overcrowding? A Real Case and a Simulation Study

Emergency department overcrowding has been reported over decades around the globe and the phenomenon is observed to be worsening in recent years. The overcrowding issue will hinder critically-ill patients from accessing timely and adequate medical services, and may result in unnecessary deaths of emergency patients. Furthermore, it may lead to patient dissatisfaction due to the many hours of waiting for consultation. While most studies suggest that there is a mismatch between demand and supply for emergency care and this is the primary factor for the phenomenon, reducing system inefficiency is a possible way to relieve the overcrowding situation when the demand and supply are not adjustable. In this paper, we study the impacts of missing patients, referring to the patients who are not present at the time that they are called for consultation. We conduct a real case study and a simulation study of an emergency department in Hong Kong. We found that even if there is only a small proportion of missing patients and their missing time is short, there is a significant increase in patient waiting time. We suggest that emergency departments should consider to adopt information technology to reduce the inefficiency due to missing patients.