Health System Patient Flow Simulation Model
Michael W. Carter
Ali Vahit Esensoy
Centre for Research in Healthcare Engineering
University of Toronto
Our cross-sector patient flow model is a system dynamics simulation focused on the flow rates of patients between health system sectors, and the feedback structures around them. It takes a whole-system, strategic perspective, and is designed to produce output that captures the direction and magnitude resulting from policy changes around patient pathways and service levels.
The model was developed within a geographically large health region of around one million people. It was constructed based on consultations with four expert panels: health policy leaders, acute, institutional and home and community care. The first panel identified the policy levers targeting flows of patients between healthcare sectors, while the other three panels were engaged to develop causal loop diagrams (CSD) that explained admission and discharge flows of their respective sectors. Qualitative input from these panels was merged with health system data to develop a stock-and-flow structure of the health region. Patients are grouped into cohorts by age, sex, clinical condition, referral source and discharge destination. The model output was validated against admission and discharge data collected over a four year period.
The model has been applied to both qualitative (CSD) and quantitative (stock and flow) decision problems. The CSD model was used by the Ontario Ministry of Health and Long Term Care to test a new slow stream rehab option for complex patients. The model demonstrated several negative unintended consequences and led the policy team to revise their recommendations. The quantitative model has been used to validate the Ontario Stroke Strategy to estimate length of stay improvements. We are currently working with the Ministry to make the tool more widely accessible