The Modeling of Interrupts and Unplanned Absences in Health Care Operations

The health care sector is a fast-growing segment of GNP in almost every economy. No wonder that we witnessed a tremendous increase in research to improve both medical practice and management practice. Patient flow management is an example of such a management practice and represents the ability of the health care system to serve patients quickly, reliably, and efficiently as they move through stages of care. This is basically a supply chain issue in the service sector in which we try to match demand and supply. Unfortunately patients still experience delays and waiting lists. This is an immediate consequence of a mismatch between demand and supply. A queueing model offers an excellent tool to analyze and improve the performance of health care systems. The purpose of this article is to discuss differences with the modeling of manufacturing systems (or more broadly supply chain issues in the health care industry compared to supply chain issues in services) and to focus on modeling issues in patient flow. In this work, we concentrate on service outages and develop new expressions to assess their impact on waiting lists and delays. Using data obtained from a Belgian hospital, these expressions are evaluated through a number of queueing models. We provide a comparison of the different queueing models and indicate which queueing technique is most appropriate to model a health care system.