Operating room planning and scheduling for outpatients and inpatients: A review and future research

In hospitals, surgeries are treated either on an outpatient or on an inpatient basis. Outpatients are normally routine patients that enter and leave the hospital on the same day, while inpatients who need more complex surgeries have to stay overnight. More recently, a shift from inpatient surgery to outpatient surgery is occurring due to scientific progress in anaesthesia and surgical techniques. Identifying possible similarities and differences between outpatient surgery scheduling and inpatient surgery scheduling can serve as a valuable decision-making foundation for practitioners and for operations researchers to efficiently schedule patients for surgery in the surgical department. This paper provides the first literature review on comparing outpatient surgery scheduling with inpatient surgery scheduling. The literature published between 2000 and 2020 that explicitly mentions either scheduling setting is included and it is analyzed from three dimensions, i.e., the uncertainty incorporation, the research methodology, and a scheduling performance comparison between both settings. We find that outpatient surgery can observe better results in many of the performance measures (i.e., operating room utilization, overtime, and patient cancellation rate) as opposed to inpatient surgery. This is due to the fact that inpatient surgery duration is longer and more variable and to the presence of more emergency patients, although there is a higher likelihood of no-shows for outpatients. Moreover, we identify future research directions that provide opportunities for expanding existing methodologies and especially for narrowing the gap between theory and practice.