A stochastic model for operating room planning under uncertainty and equipment capacity constraints


1 School of Industrial Engineering, College of Engineering, University of Tehran, Tehran, Iran

2 Department of Mechanical Engineering, Malek e Ashtar University of Technology, Shahin Shahr, Isfahan, Iran


In the present economic context, the operating
theater is considered as a critical activity in health care
management. This paper describes a model for operating
room (OR) planning under constraint of a unique equipment.
At first level we schedule elective surgeries under the
uncertainty of using a unique equipment. At the second
level we consider emergency surgeries, and at the third
level a coefficient factor for surgeons is introduced in using
this unique equipment. The planning problem consists in
scheduling a unique equipment and assigning elective
cases to different periods over a planning horizon to minimize
the sum of elective patient related costs and overtime
costs of ORs. The most important factor that we have
focused on this paper is equipment resource constraint. A
new mathematical programming model is first proposed
and at the second and third level, a new stochastic mathematical
programming model is proposed. Then sample
average approximation is presented to approximate the
problem with sample size N and then Lingo is used as an
exact approach. Because of NP-hardness, exact method
does not work for large size problems, so a Metaheuristic
approach (differential evolution) is proposed for large size
problems. Numerical results show that important gains
(approximately 3.5 % in overall cost) can be realized by
this stochastic OR planning model.