A hybrid simulation and optimisation approach for capacity allocation of operating rooms under uncertainty

Operating rooms are the most important assets of hospitals whose capacity allocation to different specialties is critical and challenging. This paper proposes a hybrid simulation and optimisation approach for the strategic surgery capacity allocation problem over a yearly horizon. First, a simulation model is proposed to specify an appropriate percentage of the total available time of operating rooms in each period which is allocated to emergency patients. Then, a new mathematical model is developed to determine the optimal capacity plan (i.e. resource allocation) for operating rooms by handling both elective and emergency patients under uncertainty of surgery demands, surgery times and length of stays. The model aims to minimise the total under-time and the number of patients on the waiting list according to their surgery priorities. A tailored fix and relax algorithm is devised to solve the problem efficiently. Finally, a real case study in a private hospital along with some test problems are provided to evaluate the proposed model and its solution method. The numerical results demonstrate the desirable performance of the proposed solution approach. Moreover, the results indicate a significant reduction in the total under-time and the number of beds allocated in each period.