Designing a master surgical schedule for Gelre Apeldoorn: increasing the efficiency of the surgical nursing wards and leveling the workload for their nursing staff by regulating the patient flow that originates from the operating room department

Problem description The amount of patients admitted to and discharged from surgical nursing wards, along with the amount of beds occupied at these wards, varies from day to day. These fluctuations are closely related to the workload of nursing staff, and are of a magnitude that they experience as unpleasant (interview with Brummelhuis, 2010, and Groters-Kremer, 2010). These fluctuations also cause inefficiency, since more fluctuation mean more beds and nursing staff are needed to cope with peaks in demand. The management believes that these fluctuations are mainly due to the current way of planning surgeries, which disregards its effect on the wards where patients recover. Previous research in Gelre Apeldoorn (Vollebregt, 2011) showed that implementing a so called Master Surgical Schedule (MSS) can, for each specialty, level the flow of patients originating from the OR department. An MSS is a cyclical schedule, in which slots of OR-time are reserved for a specific set of surgeries, allowing surgeons to decide which patients to treat in these slots. Limiting the choice of surgeries to be performed in a slot to those with similar medical and logistical properties allows the (central) planner to design a recurring sequence of slots that optimizes the efficiency of the OR and the wards. Vollebregt’s research however, was exploratory in nature and did not take into account that wards are shared by specialties, and that some specialties use multiple wards. Research goal In the current research we redesign Vollebregt’s method for creating an MSS and use a more realistic model to predict the impact it would have. The goal of this research is: “Design a Master Surgical Schedule that levels the workload and increases the efficiency of the surgical nursing wards of Gelre Apeldoorn and does not deteriorate the OR department’s efficiency” In this research we model both the current ward configuration and the proposed alterations to this configuration (variant 1D, version 4.0, as determined on November 29, 2011). Approach We determine what surgeries make up the case-mix of Gelre Apeldoorn and what the expected surgery duration, length of stay (LOS), and annual frequency are for these surgeries, based on historical data of 2011. Surgeries that occur, on average, at least once every plan cycle of two weeks are eligible for a slot of OR-time on a specific OR on a specific day in that cycle. iv To increase the percentage of the case-mix that is assigned such a slot, and to increase the MSS ability to cope with fluctuation in demand for a specific surgery, we first create sets of surgeries that use the same resources in a comparable quantity. Each set of surgeries defines a surgical case type and is assigned a number of slots corresponding to the expected demand. We create case types from the historical data using a heuristic in which several parameters can be altered. By altering these parameters we can influence which surgeries are grouped together. We create multiple sets of case types to determine what settings are the best. Each set of case types is used as input for Operating Room simulation and optimization software called “OR manager”, currently under development by Dr. Ir. E.W. Hans of the University of Twente. Using this software we assign each case type a number of slots and optimize the sequence of these slots in a two week cycle using two variations of a heuristic (again to test which is the best). We compare the performance of the resulting Master Surgical Schedules to the current planning policy in a simulation study, also with “OR manager”. Results It is apparent from the experiments we conduct that for both the current and proposed new ward configurations an MSS exists that levels the workload for nursing staff without deteriorating the OR performance compared to the current planning policy. It is also plausible that fewer beds would be needed in comparison to the current planning policy. However, we do not know the extent to which the capacities can be reduced. The number of beds needed, resulting from our model, is higher than reality for two reasons (for both the current planning policy and the MSS). First, in our model, peaks in bed utilization sometimes occur that only last for a few minutes. In practice a patient would likely be discharged a few minutes earlier to prevent this peak. Second, our simulation model does not recognize what surgeries are schedule, but to what case type those surgeries belong. This artificially increases the uncertainty in length of stay. Since this affects both the current planning policy and the MSS, it does not disprove the benefits of the MSS. However, we cannot give an exact number of beds that can be saved by an MSS. The largest bed reduction in comparison to the current planning policy that results from our model is three beds in 2012 for both the current and new ward configuration. Limitations The most important limitation of our model is that it does not include restrictions that are imposed by the availability of surgical instruments. Whether or not an MSS can be infeasible in this respect and, if so, whether it can be made feasible without deteriorating the OR and ward performance, remains to be seen. We expect this is not a bottleneck since most surgical case types consist of a variety of surgeries. Therefore the same rules that are currently in place to assure feasibility of the schedule can be used under the MSS planning policy. v Conclusion Our main goal was to “Design a Master Surgical Schedule that levels the workload and increases the efficiency of the surgical nursing wards of Gelre Apeldoorn and does not deteriorate the OR department’s efficiency”. We conclude that we succeeded in this goal for both the scenario that Gelre Apeldoorn continues to use the current ward configuration and the scenario that they implement the current plans for a new ward configuration. However, there are a few important considerations. The Master Surgical Schedules remain to be checked for feasibility judging by the available surgical instruments. Also, there are discrepancies between our model and reality. Because of this our results cannot quantify the efficiency increase and the workload leveling. However, since these discrepancies impact both our model of the current situation and our model of the MSS, we believe they do not disprove that implementing an MSS is preferable. We investigated whether implementing an MSS makes the work of surgeons repetitive and conclude that this is not the case. Recommendations As a by-product of this research, the tools that enable Gelre Apeldoorn to predict the impact of an MSS also enable them to predict the impact of other organizational changes. Examples are changes in the allocation of OR-time to specialties, and the allocation of surgical beds to specialties. We suggest this is used to further perfect these allocations before a definitive MSS is created. Also, in the final weeks of this research, plans were made to redistribute parts of the surgical case-mix between Gelre Apeldoorn, Gelre Zutphen, and the Deventer Hospital. These plans should be taken into account when creating the definitive MSS. The outcome of the optimization step that we use to create an MSS is not constant. Because of this we believe that an even better MSS is possible than the ones we created. We recommend that multiple Master Surgical Schedules are created and compared in a simulation study each time an MSS is designed. With the tools we provide this should take no more than a day. The settings used to define surgical case types in the grouping heuristic should be maintained each time an MSS is created to minimize the changes in case type definitions. The best Master Surgical Schedules should then be assessed for possible problems with the available surgical instruments and adjusted accordingly