【作者】 徐腾达；

【导师】 于学忠；

【作者基本信息】 北京协和医学院 ， 急诊医学， 2012， 博士

【摘要】 背景在许多国家的大城市中,急诊科拥挤已经成为一个很严重的医疗卫生问题。但急诊拥挤现象研究受到方法学的制约,当前缺乏被广泛认可的急诊拥挤度评价系统。目的通过初步分析急诊科病人流量和拥挤度变化规律,了解影响急诊科拥挤相关变量,探寻客观评估急诊科拥挤度测量方法；建立适合国内急诊医学运行模式的急诊科拥挤度评估系统。方法对近年来急诊科拥挤度方面的研究进行系统回顾,确定急诊科拥挤相关研究存在瓶颈及其可能对策。前瞻性观察一家大型三级综合临床教学医院2008年-2010年间急诊科病人流量和拥挤度变化规律,观察病人流量的24小时变化节律和节假日效应、政策效应。并对影响急诊科拥挤度相关因素进行多元线性回归分析,对国家急诊科拥挤评估模型模型(National Emergency Department Overcrowding Scale, NEDOCS)进行改良。并通过建立急诊拥挤相关变量库,筛选多维急诊科拥挤度评估量表(Multidimensional ED Overcrowding Scale, MEDOS)所需项目,编制MEDOS量表。最后,对直观量表评分法(视觉模拟评分方法,Visual Analogue Scale, VAS)、NEDOCS和MEDOS三种评分方法进行一致性检验。结果近年来,急诊科拥挤相关文献呈急剧上升,急诊科拥挤研究研究进入一个高速发展的阶段。1974年至1988年,14年间总论文数为8篇；1989年至2002年,14年间论文数量325篇；2003年至2012年,9年间总论文数达1254篇(79%)。报告存在急诊科拥挤的国家也越来越多(至2012年2月,报告国家达48个)。从论文的内涵质量来看,86.5%为单中心研究,目前尚无多中心随机对照临床研究,论文质量短时间内难以提高的一个重要瓶颈是——急诊科拥挤评估方法,目前尚无各研究机构都易接受的可靠的评估方法。为构建客观、可靠的急诊科拥挤度评估方法,前期进行的研究结果显示,工作日急诊病人流量24小时变化规律特征明显,病人流量高峰在20：00-22：00,低谷则在4：00-6：00,而拥挤度评分高峰和低谷滞后2小时。急诊病人流量有明显周末和长假日双峰效应,急诊病人流量也受政策性因素影响。多元线性回归分析显示时间段内(2小时)急诊来诊人数(B=0.027,P=0.001)、急诊床位占用率(B=5.25,P<0.001)、新进抢救室人数(B=0.431,P=0.003)、抢救室床位占用率(B=1.21,P=0.03)、急诊总床位占用率与下一个时段急诊科拥挤度显著相关。在构建急诊科拥挤评估量表时,考虑把“新进抢救室病人数”和“急诊抢救室床位占用率”等自变量作为量表项目纳入方法学研究。急诊科拥挤度测量方法学研究结果主要分四个部分：第一部分：直观量表评分法(VAS)研究。医师直观量表评分(VAS-p)显著低于护士直观量表评分(VAS-n),6.49±1.82vs7.12±1.78,P<0.001；信度检验(Kappa检验)显示,Kappa值为0.112,P<0.001,提示两者一致性强度微弱；因此在进行方法学对比验证时,采用两者均值,即VAS-m。第二部分：国家急诊科拥挤度评分(NEDOCS),研究结果显示NEDOCS与VAS-m(医师和护士VAS评分均值)呈显著相关(r=0.714,P<0.001),配对样本t检验显示,NEDOCS评分明显高于20倍转换后VAS-m评分(155.5±±36.4vs136±33.4,t=17.26,P<0.001)；NEDOCS实际测量值在研究中有11.4%超过200分(参考值范围为0-200),且NEDOCS模型来自美国急诊医学运行模式,而中美两国急诊运行模式存在明显差异,有必要对其进行校正。以VAS-m(20倍等比转换后)作为结局变量,急诊在床治疗病人数／急诊额定床位数(Pbed/Bt)、生命支持设备数(Xn)、最近一个看医师病人候诊时间(Wtime)和流出道梗阻率(ABI)作为自变量,进行多元线性回归分析,得到改良NEDOCS模型(NEDOCSBJ):NEDOCSBJ=83.563×(Pbed/Bt)+7.201×(Xn)+0.116×Wtime+0.302xABI+2.835第三部分：构建多维急诊科拥挤度评估量表(MEDOS),通过相关变量库筛选量表项目(共12项项目,9项客观项目,3项主观项目),研究结果显示,MEDOS均值(n=552)为25.4±5.8,范围5-39；MEDOS与VAS-m、NEDOCSBJ相关分析显示,r分别为0.664和0.939,P均<0.001；对MEDOS量表进行折半信度检验显示,Split-half系数为0.817(P<0.001),提示MEDOS量表评分法有较高内部一致性。第四部分：VAS-m、NEDOCSBJ和MEDOS三种测量方法进行一致性检验,主要采用Bland-Altman法。VAS-m、NEDOCSBJ、MEDOS三种测量方法间的一致性检验结果均未显示其中两种方法间具有可替代性。一致性较好的方法有VAS-m与NEDOCSBJ、NEDOCSBJ与MEDOS,但前者Bland-Altman图显示其95%一致性界限值从临床专业接受程度来看超出了1个拥挤度评分等级(40分)。NEDOCSBJ与MEDOS间,组内相关分析(ICC)和Bland-Altman图显示两者有较好的一致性,两者差值均值为11.96分,可能存在系统性误差,从临床专业角度来看其95%一致性界限(-6.74至30.66,<40分)和差值均值(11.96分)尚可接受。结论系统性回顾分析显示,急诊科拥挤度测量方法已经成为制约急诊科拥挤研究的瓶颈,建立客观、高效的急诊科拥挤评估方法是当前急诊临床管理工作者迫切需要解决的课题。急诊科拥挤度测量方法学研究结果显示,国家急诊科拥挤度评估(NEDOCS)方法并不适合当前国内急诊运行模式,改良后NEDOCSBJ模型对急诊科拥挤度评估和研究具有重要潜在价值,但NEDOCSBJ模型应用起来受到自变量易获得性等诸多因素制约,不利于在国内广泛应用和推广；而多维急诊拥挤评估量表(MEDOS)因其直观量化、可即时评估、采集信息点多(均衡性好)等优点,且NEDOCSBJ与具有较好的一致性,在急诊临床管理学研究中具有广阔的前景。急诊科拥挤度评估方法的建立为今后急诊科拥挤现象研究搭建了坚实的科学平台。更多还原

【Abstract】 [Background]Emergency department overcrowding (EDO) is a severe worldwide concern and is associated with significant negative outcomes, including unnecessary deaths. Yet the study of EDO is hindered by lack of widely accepted evaluation system.[Objective]To establish the objective EDO measuring method by observing emergency patient flow and EDO varying pattern as well as evaluating the variables affecting EDO. Aim to establish a practicable and balanced EDO assessment system suitable for domestic operation in Chinese ED setting.[Methods]The studies on emergency department overcrowding were systemically reviewed. The emergency patient flow and the EDO varying pattern during2008and2010in a2000-bed academic teaching hospital were observed prospectively. The rhythms of24h and the holiday effect as well as the policy effect on EDO were observed. The factors that might affect EDO were evaluated by multiple linear regression analysis. The National Emergency Department Overcrowding Scale (NEDOCS) was modified. The database of factors which might affect EDO was founded and the multidimensional ED Overcrowding Scale (MEDOS) items were screened. Consistency check among the Visual Analogue Scale (VAS), NEDOCS and MEDOS was performed.[Results]PARTIThe studies and papers about EDO are steadily increasing in recent years. The number of papers on this issue is8during1974and1988. The number elevated to325during1989and2002. Yet the number has climbed up to1254dramatically (which was79%of all the papers on this issue) during2003and2012. The number of countries which have reported ED overcrowding phenomenon has also been on the increase with the number of48till Feb2012. Among all the papers on this issue,86.5%were single institution studies. There has been no multi-center, randomized control clinical trial on this issue till now. The bottleneck of EDO research is the lack of the widely accepted EDO objective measuring technique.PART ⅡDistinctive patient flow patterns on workdays was observed with the patients volume peak flow in20:00-22:00, low ebb in4:00-6:00, while overcrowding score was2hours lag behind. Emergency patient flow significantly increased at weekend and long holiday with a bimodal pattern effect with a peak flow at10am to12pm and8pm to10pm. ER patient volume is affected by policy factors, but the changes only apply to non-critical patients while the number of critical patients remains consistent. Multivariate regression analysis showed that a period of time (2hours) emergency patient number (B=0.027, P=0.001), emergency bed occupancy rate (B=5.25, P<0.001) correlated with the next period of time ER overcrowding significantly.PART ⅢThis part was composed of four mainly results. The first one was focused on VAS evaluation. It was shown that VAS-p value evaluated by physicians was significantly lower than VAS-n value evaluated by nurses (6.49±1.82vs7.12±1.78, P<0.001). The reliability analysis (Kappa test) showed that Kappa value is as low as0.112,(P<0.001) which meant the consistency between VAS-p and VAS-n is weak. VAS-m (average value of VAS-p and VAS-n) was adopted while comparing different evaluation system.The second one was focused on NEDOCS evaluation. It is shown that the NEDOCS value correlated well with VAS-m value (r=0.714, P<0.001). The paired sample T test showed that NEDOCS significantly higher than VAS (VAS-mx20),155.5±36.4vs136±33.4, t=17.26, P<0.001.It was found that11.4%of the evaluation value of NEDOCS higher than200, the upper limit of the reference range (0-200).The reason of this phenomenon is that the Chinese emergency system is much different than that of the US. Then multiple linear regression was performed with VAS-m as outcome variable, Pbed/Bt, Xn, Wtime and ABI as independent variable. The modified NEDOCS (NEDOCSBJ) model was thus established: NEDOCSBJ=83.563x (Pbed/Bt)+7.201×(Xn)+0.116×Wtime+0.302×ABI+2.835The third one was focused on establishing multidimensional emergency department overcrowding scale (MEDOS) evaluation system through screening the variables data for scale items which include nine objective items and three subjective items. It was shown that the average value of MEDOS was25.4±5.8(n=552,5～39). The correlation analysis showed that MEDOS correlates with VAS-m (r=0.664, P<0.001) and NEDOCS (r=0.939, P<0.001). The Split-half reliability testing showed that Split-half coefficient was0.817(P<0.001) which means the high internal consistency of MEDOS evaluation system.The fourth one was focused on consistency check among VAS-m, NEDOCSBJ and MEDOS by using Bland-Altman Plot. None pairwise substitutability was found between nether VAS-m and NEDOCSBJ, or NEDOCSBJ and MEDOS, or VAS-m and MEDOS. The methods with moderately consistency included VAS-m and NEDOCSBJ, NEDOCSBJ and MEDOS. Yet the former could not be well accepted in clinical practice since the95%confidence interval of Bland-Altman plot is rather low. Intra-class correlation coefficients (ICC) of NEDOCSBJ and MEDOS, as well as Bland-Altman plot (95%limits of agreement:-6.74,30.66), was fairly acceptable, which meant the consistency between the two methods. Difference mean of the two methods was11.95which may be due to systemic bias and could also be acceptable in clinical practice.[Conclusions]The systemic review on EDO studies showed that the standardized measurement of EDO has become the bottleneck of EDO study. It is very important and urgent for ED management and staff to establish an objective and effective EDO evaluation system. It has been proved that the National Emergency Department Overcrowding Study (NEDOCS) was inapplicable in domestic emergency system due to the differences practice pattern between China and US. It seems that modified NEDOCS (NEDOCSBJ) model has potential value for EDO evaluation, yet it is less practical in emergency environment since it is difficulties to obtain the primary data, which need advance patient information track system. MEDOS seems to a promising EDO evaluation method not only because it is intuitive, ready to evaluate, but also because the availability and good proportionality and balance of the data.更多还原