Emergency and on-demand health care: modelling a large complex system

Abstract

This paper describes how system dynamics was used as a central part of a whole-system review of emergency and on-demand health care in Nottingham, England. Based on interviews with 30 key individuals across health and social care, a ‘conceptual map’ of the system was developed, showing potential patient pathways through the system. This was used to construct a stock-flow model, populated with current activity data, in order to simulate patient flows and to identify system bottle-necks. Without intervention, assuming current trends continue, Nottingham hospitals are unlikely to reach elective admission targets or achieve the government target of 82% bed occupancy. Admissions from general practice had the greatest influence on occupancy rates. Preventing a small number of emergency admissions in elderly patients showed a substantial effect, reducing bed occupancy by 1% per annum over 5 years. Modelling indicated a range of undesirable outcomes associated with continued growth in demand for emergency care, but also considerable potential to intervene to alleviate these problems, in particular by increasing the care options available in the community.

Keywords:

• emergency and on-demand health care
• A&E
• simulation
• system dynamics
• discrete event simulation

Acknowledgements

We thank the health and social care staff who assisted us in the conduct of this study and Dr Stephen Shortt, Mr James Scott, Mr John MacDonald, Dr Doug Black and the local steering committee for their contribution. We also thank Mr Steve Baxter and Mr Shaun Leah for their assistance in providing data. Nottingham Health Authority funded the project but the views expressed in the paper are those of the authors alone.