How Stochasticity and Emergencies Disrupt the Surgical Schedule

Abstract

In health care system, the operating theatre is recognized as having an important role, notably in terms of generated income and cost. Its management, and in particular its scheduling, is thus a critical activity, and has been the sub ject of many studies. However, the stochasticity of the operating theatre environment is rarely considered while it has considerable effect on the actual working of a surgical unit. In practice, the planners keep a safety margin, let's say 15% of the capacity, in order to absorb the effect of unpredictable events. However, this safety margin is most often chosen sub jectively, from experience. In this paper, our goal is to rationalize this process. We want to give insights to managers in order to deal with the stochasticity of their environment, at a tactical-strategic decision level. For this, we propose an analytical approach that takes account of the stochastic operating times as well as the disruptions caused by emergency arrivals. From our model, various performance measures can be computed: the emergency disruption rate, the waiting time for an emergency, the distribution of the working time, the probability of overtime, the average overtime, etc. In particular, our tool is able to tell how many operations can be scheduled per day in order to keep the overtime limited.

Managing urgent care in hospitals

“…Additionally, simulation is often used to validate schedules obtained using mathematical programming under different scenarios, and additional stochasticity. The resource capacity allocation problems in which the possible use of, and number of dedicated emergency ORs is decided, is evaluated using simulation (e.g., [68,225,253]). The other methodologies are seen more evenly across the various departments.…”

“…Table 2.4 lists the publications per department and planning level. [68,199,225,226,253,263] tactical [2, 8, 17, 18, 68, 93, 125, 147, 171, 195, 225-228, 249, 262, 263] operational [2, 18, 32, 61, 63, 64, 77, 93, 106, 113, 126, 153-156, 184, 192, 201, 207, 247, 249 [33,35,73,79,90,120,123,141,143,174,204,215,260] operational [16,73,84,112,143,172,202,229,234,240] N/A 2.3. Results…”

“…For the operating theater, strategic decision making involves the capacity dimensioning of OR capacity among elective and urgent patient types [68,199,226,253,263]. Not only the number of needed ORs is determined [199], but also how OR time is assigned to different patients types (e.g., evaluate the use of dedicated emergency ORs) [68,225,253].…”

“…However the performance of using dedicated ORs (or not) depends on the underlying case settings such as patient mix, volume, and number of available ORs, because conclusions differ on the effectiveness of dedicated ORs [68,195]. When urgent patients are treated in the same ORs as elective patients, they are taken into account as by allocating slack [2,113,126,153,207,225,226,247] where some part of the ORs is left unused by electives for urgent arrivals. Admission control policies are also evaluated, in which different prioritizations of urgent patients requiring surgery are evaluated [93], as well as staff shift scheduling in which staff shifts are assigned to (emergency) ORs that must quickly be able to respond to emergency arrivals [249] and possibly also treat elective patients [18].…”

“…[192] schedules non-elective patients in an emergency setting using mathematical programming, and maximize the number of patients that can be treated on time. [225] model the operating theater as a markov process, analyze patient flows through the ORs. They find the maximum capacity that may be allocated to electives while still being able to treat non-electives on time.…”