Scheduling and rescheduling elective patients in operating rooms to minimise the percentage of tardy patients

This paper considers the problem of building a schedule of elective surgery patients for a unit of a hospital. Two phases are followed. In the first phase, a tentative schedule is calculated 2 weeks before the planning period looking to minimise the percentage of tardy patients. Several weight-based short-term objective functions are defined and compared to optimise this goal in the long term. In the second phase, a second and final schedule is made a few days before the planning period, taking into account the changes in the available information. We propose a general methodology to calculate this final schedule. Several strategies to manage the types and importance of changes from the tentative schedule are presented considering the idiosyncrasy of dealing with elective patients. The computational experiments have been carried out via simulation on instances randomly generated according to the data from a Spanish hospital.