急診加護病房病人預後探討及對急診壅塞之影響

Evaluating the Outcome of Patients Admitted to Emergency Department Intensive Care Unit and the Impact on Emergency Department Overcrowding

王安怡(An-Yi Wang)

指導教授 ： 張丞圭

臺北醫學大學/公共衛生學院/傷害防治學研究所/博士(2020年)

摘要

急診加護病房(Emergency department intensive care unit, ED ICU) 設立之主要目的在於能夠緩解各專科加護病房床位短缺，ED ICU亦能夠提供一定程度之重症照護能力，評估ED ICU所收治之病人預後能夠更了解其處置成效，並且提供更好的加護病房資源分配指標。本研究為回溯式研究主要探討急診加護病房病人之預後以及設立ED ICU後對急診壅塞之影響。研究期間為2015年4月至2016年12月於台北醫學大學附設醫院急診加護病房內，床位配置為8床重症照護病床，於研究期間收案分析急診加護病房內病人特性及住院預後。
第一部分:敗血症預後
敗血症病人死亡率甚高，關於敗血症若有簡易且方便之早期評估工具協助判斷病情發展，可以作為協助醫護人員與家屬針對臨床處置上討論依據，第一部分研究著重於老人敗血症之預後分析。紅細胞分佈寬度（Red cell distribution width, RDW）為一般在評估血液中完整血球計數之一項檢驗項目，過去研究顯示RDW與心血管疾病，中風和代謝症候群的死亡率相關，收案期間總共117名65歲以上病人診斷為敗血症。平均年齡為81.5±8.3歲，死亡率為30.8％。Cox比例風險模式中，RDW的增加與死亡率顯著相關（每增加1% RDW其危險比：1.18；95％信賴區間: 1.03-1.35，p=0.019），RDW的接受者操作特性曲線（Receiver operating characteristic curve, ROC）曲線下面積為0.63（95％信賴區間: 0.52-0.74，p=0.025）。在次族群分析中以快速敗血症相關器官衰竭評分(quick Sepsis Related Organ Failure Assessment, qSOFA)為區分，qSOFA小於2分之族群，未存活出院者相對於存活出院者有較高RDW數值(17.0±3.3% vs. 15.3±1.4%, p=0.044)，研究中顯示RDW與老年敗血症患者的死亡率相關，並且相對於APACHE (Acute Physiology and Chronic Health Evaluation)II分數，研究結論顯示RDW是較為簡單的預測因子，可以搭配其他臨床指標協助評估病人預後。
第二部分: DNR病人預後
由於重症照護資源有限，為了達到有效運用，美國重症學會提出許多建議評估病人是否適合入住加護病房，對於病情過於嚴重或是已經簽署不施行心肺復甦術(Do not resuscitation, DNR)病人，因其死亡率極高，因此入住加護病房往往會被認為是無效醫療並且排擠其他重症病人之資源，然而有許多潛在因素影響病人預後，探討DNR病人之預後將更能適當分配重症資源，因此第二部分研究中探討此類病人在ED ICU之特性及預後。本研究結果顯示DNR病人入住ED ICU後，50%的病人可存活出院，在Cox比例風險模式中控制病人診斷及處置後， APACHE Ⅱ分數大於29.5分為預測病人死亡之獨立因子(危險比：2.46; 95% 信賴區間: 1.04-5.83, p=0.042)，ROC曲線下面積為0.64 (p = 0.028)，對於DNR病人使用APACHE II分數評估疾病嚴重度指標對於存活率有中度鑑別力，對於已簽署DNR病人來說，加護病房提供的照護並非全然為無效醫療，病人對重症照護仍有存活幫助。
第三部分: 敗血症病人與DNR之影響
由於敗血症在急重症為大宗，第三部分研究著重在分析敗血症病人族群中，簽署DNR對於預後之影響，在控制可能干擾預後因子如過去共病、升壓劑治療及疾病嚴重度之後，簽署DNR對於預測病人死亡率為一獨立因子(勝算比：6.22; 95% 信賴區間：2.71-17.88, p<0.001)，邏輯回歸模型中將DNR加上其他影響預後因子顯示ROC曲線下面積為0.84(95% 信賴區間: 0.77-0.92, p <0.001)，在次族群分析中65歲及80歲以上族群簽署DNR仍然唯一獨立預測因子，因此對於敗血症病人而言簽署DNR為一顯著影響存活之因子。
第四部分: 急診壅塞
第四部份研究分析在設立急診加護病房前後時期，急診病人量、檢傷分類、急診暫留時間比較，在急診加護病房開始收治病人之後，急診來診量顯著增加、檢傷分類一二級屬於危及個案比例也顯著增加，急診轉加護病房住院比例也上升，進一步分析病人在急診停留時間比較上，前後時期並無顯著差異(5.9±32.7小時 vs.5.9±73.9 小時,p=0.891)，對於創傷病人前後時期亦無隨著增加急診停留時間(2.1±10.0小時 vs.2.6±35.7小時,p=0.192)，顯示在設立急診加護病房後，隨著病人數量增多但並未增加重症病人留置於急診室，能達成一定程度改善急診壅塞狀況。
病況需要密集生命徵象監測及重症加護治療之病人，將轉入加護病房作進一步評估、監測與治療，病人收治優先順序也會參考疾病之嚴重度及病況之可逆性，對於急診來診，敗血症病人為大宗，但隨簽署不施行心肺復甦術病人數越來越多，入住加護病房往往會被認為佔用醫療資源，將增加急診擁塞狀況，然而簽署DNR之病人重症照護仍有存活助益，影響病人預後判定為多因素，需綜合生理、診斷、病史等各項指標；例如DNR病人可使用APACHEII分數評估預後，而若是合併敗血症之病人可利用RDW協助臨床醫師早期判斷病人預後，未來可能影響病人收治標準，促進加護病房資源有效利用並且可以協助急診病人動向判定，使重症資源分配更適宜、降低病人傷害，而急診加護病房之設立解決病人於急診停留時間過長，提供解決急診壅塞輸出端之方案，未來研究方向可更深入探討病人滿意度或是醫療費用之差異。

關鍵字

急診加護病房、重症照護、不施行心肺復甦術、敗血症、急診壅塞、創傷病人

並列摘要

Emergency department (ED) intensive care units (ICUs) admit patients with critical illness from the ED and provide continual critical care. ED ICUs, can act as a reservoir buffer by reducing the working pressure due to insufficient critical care beds and shortening the length of stay in ED. To evaluate the effectiveness of ED ICUs, our study examined the outcomes of patients with critical illness admitted to an ED ICU and the impact of implementing an ED ICU on ED overcrowding. This study was in Taipei Medical University Hospital’s ED ICU, which had eight ED ICU beds during the study period of April 2015 to December 2016.
Patients with sepsis have higher mortality rates. Early and convenient evaluation tools for prognostication are essential for physicians to discuss treatment plans with families.
The first section of our study focuses on outcomes of geriatric sepsis. Elderly patients (aged ≥65 years) who were admitted to the ED ICU having received a diagnosis of severe sepsis and/or septic shock were included. In total, 117 patients with a mean age 81.5±8.3years old were included. The mortality rate was 30.8%. In the multivariate Cox proportional hazards model, red cell distribution width (RDW) level was an independent variable for mortality (hazard ratio: 1.18, 95% confidence interval [CI]: 1.03-1.35 for each 1% increase in RDW, p=0.019), after adjustments for comorbidities, any diagnosed malignancies, and renal function. The area under the receiver operating characteristics (ROC) of RDW in predicting mortality was 0.63 (95% CI: 0.52-0.74, p=0.025). In the subgroup analysis, for quick Sepsis-Related Organ Failure Assessment (qSOFA) scores of <2, nonsurvivors had higher RDW levels than survivors (17.0±3.3% vs. 15.3±1.4%, p=0.044). RDW was an independent predictor of in-hospital mortality in elderly patients with sepsis. For qSOFA scores <2, higher RDW levels were associated with poor prognosis. RDW could be a potential parameter used alongside clinical prediction rules.
Critical care resource allocation is debated regarding patients who have “do not resuscitate" (DNR) status. Patients with critical illness who have DNR status have a lower priority of intensive care. The effectiveness of active intervention for these patients has not yet been fully evaluated.
The second section of our study analyzes the characteristics and outcomes of patients with critical illness and DNR status admitted to our ED ICU. The final analysis included 78 non-trauma patients with prior DNR status, of which 50% (39/78) survived to discharge. In the multivariate Cox proportional model, an APACHE II score above 29.5 was an independent predictor for mortality (hazard ratio =2.46; 95% CI: 1.04-5.83, p=0.042). We found that 50% of patients with prior DNR status upon ICU admission survived to discharge, indicating that aggressive care is not definitely futile.
The third section of our study evaluates whether DNR status affects the outcomes of patients with sepsis. In the multivariate logistic regression analysis, DNR status was an independent predictor for in-hospital mortality (odds ratio: 6.22, 95% CI: 2.71-17.88, p<0.001). The area under the ROC curve for the logistic regression model was 0.84 (95% CI: 0.77-0.92, p<0.001). In the subgroup analysis, DNR status remained an independent predictor for mortality among patients aged ≥ 65 and ≥80 years.
The final section of our study compares the number of ED patients, triage categories, and length of stay (LOS) in the ED before-and-after implementing the ED ICU. The period after ED ICU implementation had an increased number of patients, and disease severity as defined by the Taiwan Triage and Acuity Scale (TTAS) levels 1 and 2; however, the LOS in the ED did not increase significantly (5.9±32.7 hours vs.5.9±73.9 hours, p=0.891). In the subgroup analysis of trauma patients, LOS in the ED did not increase either (2.1±10.0 hours vs.2.6±35.7 hours, p=0.192).
ICU prioritization depends on disease severity, intensive care requirements, and reversibility of disease course. Most ICUs reject applications of patients with DNR status for ICU admission and regard their treatment as futile. In our study, aggressive care in the ICU in certain patients with DNR status had some survival benefits. The APACHE II score can help evaluate the prognosis of patients with DNR status. In elderly patients with sepsis, RDW was an independent predictor of in-hospital mortality and can also help clinicians more confidently recognize and predict outcomes at the initial presentation of sepsis. The prognostication of critical illness is multifactorial; physicians should combine patient’s previous health statuses with multiple physiological parameters to discuss the likely prognose with patients and their families. The final section of our study demonstrated that implementation of an ED ICU could be one of the throughout solution to ED overcrowding. Further research on medical costs of ED ICUs is warranted.

並列關鍵字

Emergency department intensive care unit, critical care, Do-Not-Resuscitate, sepsis, ED overcrowding

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