University of Twente Student Theses


Improving surgery scheduling for urology and vascular surgery in UMC Utrecht

Hoeksema, Menno (2010) Improving surgery scheduling for urology and vascular surgery in UMC Utrecht.

[img] PDF
Abstract:Problem description The operating room (OR) department of UMC Utrecht faces a high demand for surgery time. However, the amount of surgery time it can offer is limited, because both surgical technologists and anesthesia assistants are scarce. The shortage of personnel is caused by a shortage of qualified OR- and anesthesia-assistants in the Netherlands. This leads to cancelled days of surgery because of personnel shortage. Therefore, the production quota is not met. However, the available surgery time in UMC Utrecht is not utilized completely. In 2008, the gross utilization of the ORs was 89%, so 11% of the available time was not used for surgeries or changeovers. On the other hand, overtime occurred on 36% of the OR-days (an OR-day is one day of surgery in one OR), with an average duration of almost one hour. On top of this, 8.3% of the surgeries were cancelled on the day they were scheduled. Despite that other hospitals encounter the same problems, we strive to improve this situation. Simulation The high amount of resources involved when scheduling the OR and the stochastic nature of surgery durations make it hard to use an analytical approach to improve surgery scheduling. Simulation handles stochastic processes well and is able to evaluate several alternative solutions, whilst producing quantitative results. E.W. Hans developed a simulation model for the OR, which we adapt to serve as a basis for a simulation model in this research, and for other research projects in the OR of UMC Utrecht. Research objectives To restrict the scope of this research, we focus on the surgeries of urology and vascular surgery. We want to improve the problems we mentioned with the following objectives: Decrease the percentage of cancelled surgeries and increase utilization while not increasing overtime. Adapt and implement a simulation model of urology and vascular surgery in the operating department of UMC Utrecht.Approach We have studied related literature and designed several interventions that may improve OR performance. These interventions include a change of the number of working hours per day, the scheduling heuristic used, the use of a Master Surgery Schedule (MSS), and a combination of these interventions. An MSS contains slots for surgery types that recur regularly and is cyclically executed [Van Oostrum et al. 2009]. We adapted and implemented a simulation tool for two specialties (urology and vascular surgery) of the OR department of UMC Utrecht based on software developed in cooperation with University of Twente, called OR Manager. We used this tool to evaluate the effects of the interventions. Conclusions We performed a simulation study of the aforementioned interventions, from which we have drawn several conclusions: • Adapting working hours to the MSS (for example, schedule one surgery of 7 hours and 3 surgeries of 3 hours respectively in one day of 7 hours and one day of 9 hours, instead of two days of 8 hours) helps to reduce the number of cancellations by 1 percentage point, with a loss of utilization of 1.4 percentage points. • Longer working days allow a higher utilization with a lower amount of overtime, while the number of cancellations is not influenced. Utilization increases up to 5 percentage point for vascular surgery and overtime decreases up to 68% for urology, when twelve hours of surgery are scheduled per OR per day. • Moving delayed surgeries at the end of the day from one OR to the other helps to decrease the number of cancellations by 1.4 percentage points and increase utilization by 0.8 percentage points. • A combination of the interventions can reduce the number of cancellations by 50%, does not increase overtime and at the same time increase the utilization by 0.9 to 1.5 percentage points. Recommendations In de current situation, there are limited incentives for specialties to make good use of the resources on the OR. For example, scheduling too many surgeries on an OR-day can be a way to perform more surgeries, but has a negative effect on the expected overtime. We advise to implement a judgment of the OR performance of each specialty based on overtime,cancellations and utilization. This creates an incentive for OR performance improvement. A pilot implementation based on simulation outcomes of urology and vascular surgery will then be followed with great interest by other specialties and may result in a broad acceptance of the simulation tool. This could ultimately lead to a simulation of the entire OR department, including main resources and emergency surgeries.
Item Type:Essay (Master)
UMC Utrecht
Faculty:BMS: Behavioural, Management and Social Sciences
Subject:85 business administration, organizational science
Programme:Industrial Engineering and Management MSc (60029)
Link to this item:
Export this item as:BibTeX
HTML Citation
Reference Manager


Repository Staff Only: item control page