急診為醫療體系中的重要一環，然而近年來急診的服務量日漸增多，但醫院的空間與人力配置皆未改變，使得急診壅塞日漸嚴重。為了使病情較嚴重的病患能得到妥善的治療，急診醫療團隊皆積極地開發出理想的檢傷分類系統以因應時勢。然而仍舊有四成的比例超出建議的候診時間，代表著急診壅塞最根本的問題仍舊存在。
造成此壅塞的情形主要是有限的醫療資源、急診流程效率不佳以及環境變異所致，因此如何在流程與需求變異的環境下，能夠縮減病患平均等候時間進而妥善運用醫療資源即為本研究所關切的議題。
本研究以精實觀點，針對急診流程繪製價值流圖(Value Stream Mapping，VSM)找出浪費之所在，從中分析出病患等待過久的原因為醫護人員必須在各病床間移動，進而造成急診流程效益不彰。因此，設計單元工程佈置以減少過多的走動，除此之外單元工程也能夠適應需求不確定下進行醫護人員的最佳化配置。本研究依據急診環境產出4種單元工程佈置(Cell)方案進行分析與比較，分別為1.分段式單元工程，將醫師判斷檢查結果與給藥放置在內科診療區2.分段式單元工程，將醫師判斷檢查結果與給藥放置在內科留觀區3.直線型單元工程，將所有流程皆合併在同一個單元工程4.U型單元工程，將所有流程皆合併在同一個單元工程。其次，建構模擬模式來模擬真實環境與單元工程方案，並以模擬最佳化求解不同班別的醫護人員配置可發現直線型設計相較於其他三種設計可使病患流動更為順暢並進而減少護理人員，最後以某醫學中心為實際案例說明導入之過程。
在情境分析後可發現直線型單元工程可從護理人力9名減少至6名的情況下，並能使病患的平均等候時間從64.97分鐘減少為38.49分鐘，改善幅度為40.76%；超過建議候診人數比例也從45.14%下降至12.06%，改善幅度為73.28%；由此可知運用精實管理並設計單元工程佈置可在急診環境中有效消除系統中的浪費。

Emergency department (ED) plays an important role of the health care system. The increases in patient volume and the total number of EDs decline cause the phenomenon of crowding over the past decade around the world. In order to let most urgent cases get the proper treatment, each country constructs the emergency severity index (ESI) triage. However, the percentage of average wait time to see physicians was still more than 40% as recommended time.
The causes of this congestion situation are the dynamic variation of system and constraint of resources. Therefore, the motivation of the present study is to allocate the resources for the propose of shorten the patients’ average waiting time.
First, the study applies the Value Stream Mapping (VSM) to find out the waste among the process. Second, we design four cell layouts to shorten the distance of movement by medical staff. The four kinds of cell layouts are followings: 1.The segment layout with the process of doctor review and nurse observation in non-traumatic treatment area. 2. The segment layout with the process of doctor review and nurse observation in observation area. 3. The linear layout. 4. The U-form layout with the processes of doctor observation, nurse observation, imaging, doctor review and nurse observation in the same arena. Third, constructs the discrete-event simulation for the current ED system and the four cell layouts. The decision variables of allocation doctors, nurses into cells among each shift of a day and dispatching rules will be decided by simulation optimization. Finally, a practical case is adopted for empirical illustrations.
According to the scenarios analysis, we find out the design of the linear layout is better than others not only decrease the amount of medical staffs but also the patients’ average waiting time. The patients’ average waiting time is reduced from 64.97 minutes to 38.49 minutes, which is a 40.76% improvement. The percentage of average wait time to see physicians is reduced from 45.14% to 12.06%, which is a 73.28% improvement. The amount of nurses is also reduced from 9 to 6. Therefore, by applying the lean management and the design of cell layout can eliminate the waste amount the system.

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