Biomedical Equipment Technology Department, Sana'a Community College, Sana'a, Yemen.
Department of Biomedical Engineering and Systems, Faculty of Engineering, Cairo University, Giza, Egypt.
J Med Eng Technol. 2020;44(7):411-422. doi: 10.1080/03091902.2020.1799096. Epub 2020 Sep 4.
In this paper, the medical equipment replacement strategy is optimised using a multistage stochastic dynamic programming (SDP) approach. The outcome is an optimal path which shows whether to keep an existing piece of medical equipment (defender) or replace it with a more economical alternative (challenger). We assume that each decision can result in a number of different possible outcomes, each with a known probability. Contrary to deterministic dynamic programming, the state at the next stage is not completely determined by the state and policy decision at the current stage. Instead, the next stage depends on the operation and maintenance cost which is modelled as a stochastic variable. A Keep-Replace sequence of the highest returns (lowest costs) is the result of solving the problem using forward decision making. The benefit of the SDP solution versus that of keeping medical equipment until the end of its expected life is investigated for three scenarios: (1) no revenue for the defender and the challenger, (2) equal revenues for both, and (3) higher revenue for the challenger. The percentage of benefits relative to the current acquisition cost for the three scenarios are 616.9%, 728.2%, and 789.29%, respectively. Each percentage represents the relative difference between the equipment life cycle cost of the optimal sequence and that of the conventional sequence.
本文采用多阶段随机动态规划 (SDP) 方法优化医疗设备更换策略。结果是一个最优路径，显示是保留现有的医疗设备（防御者）还是用更经济的替代品（挑战者）来替换它。我们假设每个决策都可能导致许多不同的可能结果，每个结果都有已知的概率。与确定性动态规划不同，下一阶段的状态不完全由当前阶段的状态和策略决策决定。相反，下一阶段取决于作为随机变量建模的操作和维护成本。使用前向决策解决问题的结果是最高回报（最低成本）的保留-更换序列。针对三种情况研究了 SDP 解决方案相对于将医疗设备保留到预期寿命结束的优势：（1）防御者和挑战者都没有收入，（2）两者收入相等，（3）挑战者收入更高。相对于三种情况的当前购置成本，收益的百分比分别为 616.9%、728.2%和 789.29%。每个百分比表示最优序列和传统序列的设备生命周期成本之间的相对差异。
