Emergency – but no accident – a system dynamics study of an accident and emergency department

Public concern over long waiting times for admissions motivated this study, whose aim was to explore the factors which contribute to such delays. In collaboration with a major London teaching hospital, a system dynamics model of the interaction of demand pattern, A&E resource deployment, other hospital processes and bed numbers was developed. The analysis indicates that while reductions in bed numbers increase waiting times for emergency admissions to a small extent, their principal effect is to increase sharply the number of cancellations of admissions for elective surgery. This suggests that basing A&E policy solely on any single criterion will suceed in transferring the effects of a resource deficit to a different patient group.