目標：利用全民健保資料檔檢視我國急診病患之急診暫留情形及急診長時間暫留相關因素探討。方法：採橫斷式研究法，利用2005年衛生署全民健保門住診資料選取該年急診就診個案。利用邏輯斯迴歸分析影響不同急診暫留時間之相關因素探討。結果：2005年急診就醫總人次為6,508,597人次，平均當年度每百人就醫次數為26.43次，急診後留觀率為7.7%，留觀者中留觀超過一日佔13.0%，留觀超過二日佔5.6%。急診留觀情形受病患特質（年齡越大、男性、非假日就醫、緊急程度越高、共病情形嚴重、非重大傷病者）、區域特質（居住地都市化程度越低、在地就醫）、醫院特質（公立醫院、醫學中心、教學醫院、總佔床率高、急診量高或低者）等影響。急診留觀者（暫留大於六小時者）中是否需留觀超過一日或超過二日，皆以假日就醫、重大傷病身份、非緊急程度、跨區就醫、至急診量低的醫院就醫易超長急診留觀。結論：我國急診留觀時間過長情形仍舊存在，應加強輔導改善，以提升急診醫療品質。

Objectives: The National Health Insurance database was used to explore the length of stay (LOS) and related factors in patients utilizing emergency rooms. Methods: In this cross-sectional study, patient use of emergency medical care was analyzed using clinic and hospital claims data from the Bureau of National Health Insurance (BNHI) in 2005. The factors related to emergency department length of stay (EDLOS) were analyzed by logistic regression. Results: There were 6,508,597 persons who had used emergency medical services in 2005, averaging every hundred human of every year 26.43 times. The was 7.7% patients staying at emergency room for observation, 13% and 5.6% of these patients staying at emergency room longer than one and two days for observation, respectively. Patient characteristics associated with EDLOS included old age, male gender, and visiting during a non-holiday. In addition, the presence of urgent medical conditions, comorbidity, or non-serious illness was associated with EDLOS. The regional characteristics associated with EDLOS were as follows: less urbanized area and local visits. Public, medical centers and teaching hospitals with higher occupancy rates and extremely high or low emergency visits were also associated with EDLOS. An observation time of more than one or two days was also influenced by these characteristics including a holiday visit, serious illness, non-urgent illness, visiting at hospital with low emergency department service volume, and cross-boundary visits. Conclusions: The length of stay in emergency rooms still long in Taiwan. Interventions for facilitating emergency medical services are necessary for improving quality.