A planning and scheduling problem for an operating theatre using an open scheduling strategy

The objective of this paper is to design a weekly surgery schedule in an operating theatre where time blocks are reserved for surgeons rather than specialities. Both operating rooms and places in the recovery room are assumed to be multifunctional, and the objectives are to maximise the utilisation of the operating rooms, to minimise the overtime cost in the operating theatre, and to minimise the unexpected idle time between surgical cases. This weekly operating theatre planning and scheduling problem is solved in two phases. First, the planning problem is solved to give the date of surgery for each patient, allowing for the availability of operating rooms and surgeons. Then a daily scheduling problem is devised to determine the sequence of operations in each operating room in each day, taking into account the availability of recovery beds. The planning problem is described as a set-partitioning integer-programming model and is solved by a column-generation-based heuristic (CGBH) procedure. The daily scheduling problem, based on the results obtained in the planning phase, is treated as a two-stage hybrid flow-shop problem and solved by a hybrid genetic algorithm (HGA). Our results are compared with several actual surgery schedules in a Belgian university hospital, where time blocks have been assigned to either specific surgeons or specialities several months in advance. According to the comparison results, surgery schedules obtained by the proposed method have less idle time between surgical cases, much higher utilisation of operating rooms and produce less overtime.     

基于CMBBO的医院管理资源调度

手术室资源调度关系到医院资源配置的合理性,对医院竞争力具有至关重要的影响.针对BBO算法收敛速度效率低、易陷入局部最优的缺陷,提出了云模型BBO算法,并结合所建立的医院手术室资源调度模型,提出了一种基于CMBBO的医院手术资源调度模型.将该模型应用于某大型三甲医院,结果表明手术资源使用率和手术服务能力得到提升、手术等待...     

A two level metaheuristic for the operating room scheduling and assignment problem

Given a surgery department comprising several specialties that share a fixed number of operating rooms and post-surgery beds, we study the joint operating room (OR) planning and advanced scheduling problem. More specifically, we consider the problem of determining, over a one week planning horizon, the allocation of OR time blocks to specialties together with the subsets of patients to be scheduled within each time block. The aim of this paper is to extend and generalize existing approaches for the joint OR planning and scheduling problem. First, by allowing schedules that include patients requiring weekend stay beds which was not the case previously. Second, by tackling simultaneously both the OR planning and patient scheduling decision levels, instead of taking them into account in successive phases. To achieve this, we exploit the inherent hierarchy between the two decision levels, i.e., the fact that the assignment decisions of OR time blocks to surgical specialties directly affect those regarding the scheduling of patients, but not the reverse. The objective function used in this study is an extension of an existing one. It seeks to optimize both patient utility (by reducing waiting time costs) and hospital utility (by reducing production costs measured in terms of the number of weekend stay beds required by the surgery planning). 0–1 linear programming formulations exploiting the stated hierarchy are proposed and used to derive a formal proof that the problem is NP-hard. A two level metaheuristic is then developed for solving the problem and its effectiveness is demonstrated through extensive numerical experiments carried out on a large set of instances based on real data.     

New heuristics for planning operating rooms

We tackle the operating room planning problem of the Plastic Surgery and Major Burns Specialty of the University Hospital “Virgen del Rocio” in Seville (Spain). The decision problem is to assign an intervention date and an operating room to a set of surgeries on the waiting list, minimizing access time for patients with diverse clinical priority values. This problem has been previously addressed in the literature considering different objective functions. The clinical priority depends on the surgery priority and the number of days spent on the waiting list. We propose a set of 83 heuristics (81 constructive heuristics, a composite heuristic, and a meta-heuristic) based on a new solution encoding, and we compare these methods against existing heuristics from the literature for solving operating room planning problems. The heuristics are adapted to the problem under consideration (i.e. considering all constraints and the new objective function), being re-implemented using the information provided by the authors. In total, after a calibration procedure, we compare 17 heuristics. The computational experiments show that our proposed meta-heuristic is the best for the problem under consideration. Finally, the proposed heuristics are tested using data from the Plastic Surgery and Major Burns Specialty. The results show significant improvements on several key performance indicators (number of scheduled surgeries, quality of surgical plan, resources utilization, etc.) when comparing with the actual results obtained by the specialty in the current practice. The aforementioned hospital is currently implementing the heuristic methods.     

Optimization of layout and path planning of surgical robotic system

Positioning a surgical robot for optimal operation in a crowded operating room is a challenging task. In the robotic-assisted surgical procedures, the surgical robot’s end-effector must reach the patient’s anatomical targets because repositioning of the patient or surgical robot requires additional time and labor. This paper proposes an optimization algorithm to determine the best layout of the operating room, combined with kinematics criteria and optical constraints applied to the surgical assistant robot system. A new method is also developed for trajectory of robot’s end-effector for path planning of the robot motion. The average deviations obtained from repeatability tests for surgical robot’s layout optimization were 1.4 and 4.2 mm for x and y coordinates, respectively. The results of this study show that the proposed optimization method successfully solves the placement problem and path planning of surgical robotic system in operating room.

     

集成手术排程和护士排班的中期决策优化研究

在手术需求增大与医护人员短缺的矛盾下如何合理安排手术和配置医护资源,解决手术室实际运作中资源负荷不均衡现象,是当前手术室运作管理中亟待解决的难题。然而手术排程和手术室护士排班作为手术室科学管理的核心决策问题,却有着不同的时间域,并且会相互影响。在考虑科室手术和手术室护士偏好等硬约束和软约束前提下,构建一个集成手术排程和护士排班的手术室中期集成决策模型,设计了具有双层嵌套路径化结构的蚁群算法。通过某三甲医院10天的实际手术室运作数据,进行算法对比和分析评价,验证了算法在解决集成决策问题上的可行性和有效性。     

A simulation of emergency rooms

The purpose of this paper is to provide a framework for the planning and staffing of an emergency room in a hospital. The problem is to find the optimal number of service units (stations) and their staffing pattern under regular operating conditions and in a period of peak demand. Presented in a simulation model of a simplified case, which can be extended for more complicated situations. The simulation can facilitate planning, budgeting, decision-making, and managerial control by providing management with information about costs, waiting time of patients and idleness of facilities.     

Teamwork enables remote surgical control and a new model for a surgical system emerges

Technology has revolutionised surgery in minimising anatomical invasiveness and increasing the range of surgical interventions available. However, modern remote and robot assisted surgery places unorthodox demands on surgeons and on all those involved in surgical operations in the operating theatre/room. This system of work is of vital importance to surgical success. However, research for developing surgical technique focuses mainly on the surgeon’s interface with the operative site, neglecting the operating room system supporting that technique. Furthermore, there is yet no agreement on the framework for regularly organising this vital system and for optimising its design for interprofessional work. By expanding on the conventional human–machine interface, we develop a model depicting the surgeon controlling surgical action through the media and technology of the operating room system. We show how the operating room team mediate the control of the surgical operation. By viewing control and communication in the operating room as a property of a distributed or joint cognitive system, we emphasise the potential for the team, their media and technology to either impair or enhance surgical performance.     

无菌条件非接触式多通道自然交互手术环境

无菌和非接触环境是医疗手术室的基本要求,这使得计算机操作室和手术室需要在物理上隔离.同时,因为手术进行中,主治医生如果需要查看病灶图像,通常授意护士或者手术助理到计算机操作室操作病灶图像,由于手术室和计算机操作室间的隔离,以及主治医生和助理间可能存在的意图理解不准确,容易导致护士或者手术助理在手术室和计算机操作室往返多次,这增加了患者手术时间延长、失血增多、脏器暴露时间长等风险,尽量减少手术中定位到病灶图像的时间对于医生和病人都很重要.针对上述需求,借助遮挡环境下的深度图像人体骨架提取、手势跟踪与理解、手术室环境远场语音识别,多模态信息处理与融合技术,构建无菌条件下的非接触式多通道自然交互手术环境.该环境使得主治医生在手术中可通过语音命令、手势及上述交互方式相结合的方式快速定位到需要观察的病灶成像.在接近真实环境的实验环境中,建立的无菌条件的非接触式多通道自然交互手术环境在保证精度的情况下,可显著缩短病灶图像定位时间.无菌环境智能交互医疗手术室为未来下一代高效的手术提供了技术与方法验证.     

Maximizing the efficiency of use of nurses under uncertain surgery durations: A case study

This paper studies a nurse scheduling problem of assigning a set of nurses to surgeries scheduled on each workday in an operating room (OR) suite. This problem plays a decisive role in utilizing nurses efficiently, which is of paramount importance for OR suites to provide high-quality service at ever reduced cost. Due to significant uncertainty in surgery durations, designing schedules that achieve high nurse efficiency is complicated by the competing objective of ensuring on-time starts of surgeries. For trading off between the two performance criteria, we formulate the problem as a mixed integer programming (MIP) model with explicit probability modeling of uncertainty. We are concerned about improving nurse efficiency in terms of overtime and idle time of nurses while mastering the risk of delay of surgeries. The MIP model is applied in a large size Chinese hospital, and the results are compared with the actual performance of the OR suite. The comparisons reveal that through examining the trade-off between the performance criteria, important nurse efficiency improvements can be achieved with good on-time start performance. Moreover, the applicability of the MIP model in various problem settings is also investigated.     

Logistical support scheduling under stochastic travel times given an emergency repair work schedule

Stochastic factors during the operational stage could have a significant influence on the planning results of logistical support scheduling for emergency roadway repair work. An optimal plan might therefore lose its optimality when applied in real world operations where stochastic disturbances occur. In this study we employ network flow techniques to construct a logistical support scheduling model under stochastic travel times. The concept of time inconsistency is also proposed for precisely estimating the impact of stochastic disturbances arising from variations in vehicle trip travel times during the planning stage. The objective of the model is to minimize the total operating cost with an unanticipated penalty cost for logistical support under stochastic traveling times in short term operations, based on an emergency repair work schedule, subject to related operating constraints. This model is formulated as a mixed-integer multiple-commodity network flow problem and is characterized as NP-hard. To solve the problem efficiently, a heuristic algorithm, based on problem decomposition and variable fixing techniques, is proposed. A simulation-based evaluation method is also presented to evaluate the schedules obtained using the manual method, the deterministic model and the stochastic model in the operation stage. Computational tests are performed using data from Taiwan’s 1999 Chi-Chi earthquake. The preliminary test results demonstrate the potential usefulness of the proposed stochastic model and solution algorithm in actual practice.     

The development of an integrated haptic VR machining environment for the automatic generation of process plans

In modern manufacturing it is crucial to be able to produce a product right first time, as efficiently as possible. Virtual prototyping can play a key part in fulfilling this requirement, allowing the simulation of production in advance without the need for unnecessary downtime, material waste or increased lead times. This makes virtual reality (VR) potentially an ideal planning tool since, with each simulation, a better understanding of requirements can be reached and a more effective solution found.     

A decision support system for cyclic master surgery scheduling with multiple objectives

This paper presents a decision support system for cyclic master surgery scheduling and describes the results of an extensive case study applied in a medium-sized Belgian hospital. Three objectives are taken into account when building the master surgery schedule. First of all, the resulting bed occupancy at the hospitalization units should be leveled as much as possible. Second, a particular operating room is best allocated exclusively to one group of surgeons having the same speciality; i.e., operating rooms should be shared as little as possible between different surgeon groups. Third, the master surgery schedule is preferred to be as simple and repetitive as possible, with few changes from week to week. The system relies on mixed integer programming techniques involving the solution of multi-objective linear and quadratic optimization problems, and on a simulated annealing metaheuristic.     

Robotic surgery setup simulation with the integration of inverse-kinematics computation and medical imaging

At present, there are representative robot operation systems such as da Vinci and ZEUS which have realized minimally invasive surgery by the use of dexterous manipulators. In the operating room, medical staff must prepare and set up an environment in which the robot has optimal freedom of motion and its functions can be fully demonstrated for every case. The range of motion in which the robot can reach and be maneuvered is restricted by the fixed point of the trocar site. We have developed a preoperative planning system with the function of volume rendering of medical images and automatic positioning by applying an inverse-kinematics computation of surgical robot. The motion of a surgical robot can be simulated in advance with the intuitive interface and kinematics computation program running in the background of the system. If robotic surgery planning with volume rendering of DICOM images is possible, the discussion of a surgical plan can be directly made just after the diagnosis considering the patient-specific structure. This kind of setup platform would be essential for the future introduction of surgical robotics into an operating room.     

Opportunities and challenges in improving surgical work flow

Safe and efficient surgical operations depend on a work environment larger than the individual operating room (OR) and on communications at different levels of the hospital organization. Extensive communication is needed before and during surgery to ensure that surgical rooms, equipment, and supplies; patients; surgeons; supporting personnel; and accompanying documentation are all ready at the appropriate times. In this article, we compile the results of three of our studies of communication activities outside ORs, with the goal of identifying opportunities and challenges in the workflow of surgery. The first study demonstrates the amount of communication work performed by OR coordinators. The second study demonstrates the potential functions of a whiteboard in communication. The third study describes an organizational learning strategy of proactive event reporting. We apply computer-supported cooperative work and organizational learning concepts to the findings and suggest ways in which information technology may improve surgical workflow.     

A variable neighborhood search algorithm for the surgery tactical planning problem

We address the tactical planning problem of surgeries that consists in building an admission plan of patients over a medium-term horizon planning so as to minimize over and under utilization of several resources such as operating theaters, beds and nursing care, compared with their target level of utilization. The problem is formulated as a mixed integer linear program for which exact solution methods fail to find an optimal solution in a reasonable execution time. We develop a Variable Neighborhood Search algorithm and show its ability to provide high quality solutions in short computational running times compared with CPLEX for numerous real-sized instances based on the surgery planning problem in a Dutch cardiothoracic center. Furthermore, with few parameters' settings and low computational memory requirements, this approach may easily be implemented in a decision support system for hospitals.     

Sequencing surgical cases in a day-care environment: An exact branch-and-price approach

In this paper we investigate how to sequence surgical cases in a day-care facility. We specify a multi-criteria objective function in which we minimize the peak use of recovery beds, the occurrence of recovery overtime and the violation of various patient and surgeon preferences. The limited availability of resources and the occurrence of medical precautions, such as an additional cleaning of the operating room after the surgery of an infected patient, are taken into account. We apply column generation to solve this combinatorial optimization problem and propose a dynamic programming algorithm to solve the pricing problem. The computational efficiency of this dynamic programming approach is validated through comparison with a mixed integer linear programming approach. In order to obtain integer variables, we embed the column generation loop in an enumerative branch-and-price framework. We elaborate on various branching strategies and branching schemes and examine their impact on the solution quality. The test instances for the computational experiments are generated using real-life data of the surgical day-care center at the academic hospital UZ Leuven Campus Gasthuisberg (Belgium).     

Optimal scheduling of emergency roadway repair and subsequent relief distribution

Emergency roadway repair and relief distribution planning following a natural disaster has traditionally been done manually and separately, based on the decision-maker's experience, disregarding the interrelationship between emergency roadway repair and relief distribution from the system perspective, which may yield inferior solutions. Hence, in this research we consider minimizing the length of time required for both emergency roadway repair and relief distribution, as well as the related operating constraints, to develop a model, for planning emergency repair and relief distribution routes and schedules within a limited time. We construct a time–space network for emergency repair and another for relief distribution. A number of operational constraints are set between these two networks according to real constraints. Our model is a multi-objective, mixed-integer, multiple-commodity network flow problem. We adopt the weighting method and develop a heuristic to efficiently solve this problem in practice. To evaluate our model and the solution algorithm, we perform a case study. The results show the model and the solution algorithm could be useful in practice.     

Stochastic programming analysis and solutions to schedule overcrowded operating rooms in China

As a result of the growing demand for health services, China's large city hospitals have become markedly overstretched, resulting in delicate and complex operating room scheduling problems. While the operating rooms are struggling to meet demand, they face idle times because of (human) resources being pulled away for other urgent demands, and cancellations for economic and health reasons. In this research we analyze the resulting stochastic operating room scheduling problems, and the improvements attainable by scheduled cancellations to accommodate the large demand while avoiding the negative consequences of excessive overtime work. We present a three-stage recourse model which formalizes the scheduled cancellations and is anticipative to further uncertainty. We develop a solution method for this three-stage model which relies on the sample average approximation and the L-shaped method. The method exploits the structure of optimal solutions to speed up the optimization. Scheduled cancellations can significantly and substantially improve the operating room schedule when the costs of cancellations are close to the costs of overtime work. Moreover, the proposed methods illustrate how the adverse impact of cancellations (by patients) for economic and health reasons can be largely controlled. The (human) resource unavailability however is shown to cause a more than proportional loss of solution value for the surgery scheduling problems occurring in China's large city hospitals, even when applying the proposed solution techniques, and requires different management measures.     

Anytime search in dynamic graphs

Agents operating in the real world often have limited time available for planning their next actions. Producing optimal plans is infeasible in these scenarios. Instead, agents must be satisfied with the best plans they can generate within the time available. One class of planners well-suited to this task are anytime planners, which quickly find an initial, highly suboptimal plan, and then improve this plan until time runs out.A second challenge associated with planning in the real world is that models are usually imperfect and environments are often dynamic. Thus, agents need to update their models and consequently plans over time. Incremental planners, which make use of the results of previous planning efforts to generate a new plan, can substantially speed up each planning episode in such cases.In this paper, we present an A^∗-based anytime search algorithm that produces significantly better solutions than current approaches, while also providing suboptimality bounds on the quality of the solution at any point in time. We also present an extension of this algorithm that is both anytime and incremental. This extension improves its current solution while deliberation time allows and is able to incrementally repair its solution when changes to the world model occur. We provide a number of theoretical and experimental results and demonstrate the effectiveness of the approaches in a robot navigation domain involving two physical systems. We believe that the simplicity, theoretical properties, and generality of the presented methods make them well suited to a range of search problems involving dynamic graphs.