| 摘要: | 背景：慢性肺阻塞疾病(Chronic Obstructive Pulmonary Disease, COPD)會造成吐氣氣流受阻而造成所謂空氣滯積(air trapping)，進而形成肺氣腫，而在此狀態下容易形成肺泡性死腔，造成病患低血氧、喘咳、呼吸困難及運動能力受限等症狀。此外，肺氣腫患者可能因滯留的二氧化碳造成痰液黏稠或是反覆呼吸道感染，另外也容易引發心血管疾病之共病症，形成肺心病情形。而新興指標--距離與低血氧乘積(Distance-saturation product, DSP)可綜合評估病患六分鐘行走距離及血氧變化情形，也可預測病患死亡率，然而其對COPD肺氣腫程度的影響尚未明瞭。因此，本研究目的為探討COPD病患的DSP與肺氣腫嚴重程度之相關性，並與目前較常使用的運動後血氧(post-SpO2)做評估肺氣腫的成效比較。
方法：本實驗採橫斷性研究，於衛生福利部雙和醫院共收案139位COPD病患。收集參數包括病患基本資料、電腦斷層掃描、肺功能檢查、六分鐘走路測試、運動前後血氧數值、血液檢查、與急性惡化次數之數據，並依據文獻將DSP參數290m%分為低DSP組與高DSP組。利用皮爾森相關係數(Pearson’s correlation coefficient)分析關聯性，並使用羅吉斯回歸(Logistic regression analysis)分析風險影響因子，設定p <0.05 為顯著差異水準，再利用接受者操作特徵曲線(Receiver-operating-characteristic curve, ROC curve)分析兩種指標的敏感度及特異性。
結果：統計結果顯示，低DSP組相較於高DSP組，於年齡、患者呼吸困難評估量表(mMRC)、慢性阻塞性肺病評估量表(CAT)、急性惡化次數、肺氣腫嚴重程度、肺功能測試、六分鐘走路距離、運動血氧皆有顯著差異。並且於嚴重程度肺氣腫組別中，發現低DSP組別的肺氣腫嚴重程度較高DSP組高，且在肺功能測試以及COPD症狀相關量表都較差。相關性結果顯示，DSP與運動後血氧都與mMRC、急性惡化次數、低衰減區域(Low attenuation area, LAA)、肺功能測試、六分鐘行走測試有相關，另外DSP與患者的性別、CAT以及淋巴性白血球有相關性。DSP於羅吉斯回歸建模顯示其對LAA的風險並沒有運動後血氧來的高，但對於患者急性惡化的風險影響較運動後血氧為高。ROC曲線顯示，使用DSP作為病患肺氣腫嚴重程度的初步判斷依據較單純使用運動後血氧為佳。
結論：本研究顯示DSP與COPD病患肺氣腫嚴重程度有負相關，並且DSP小於290m%的嚴重程度肺氣腫患者肺功能與六分鐘行走測試表現都較大於290m%的組別來的低，呼吸症狀如喘的表現較嚴重。DSP於ROC曲線顯示，比運動後血氧用於評估患者肺氣腫嚴重程度較有鑑別度。
Background: Chronic obstructive pulmonary disease(COPD) causes air trapping by restricting expiratory flow, then leads to pulmonary emphysema, forming physiological dead space which making patients get desaturation, dyspnea and impaired exercise capacity. Besides, patients with pulmonary emphysema could have stick sputums or repeat respiratory infection caused by accumulated carbon dioxide in lung, then induced comorbidities such as cardiovascular disease, resulting cor pulmonale. Distance-saturation product, a novel index, is able to evaluate 6-minute walking distance(6MWD) and oxygen saturation together, and also predict mortality, however, its’ relationship to COPD pulmonary emphysema severity hasn’t been clarified. Therefore, the aim of this study is to discuss the correlation between pulmonary emphysema severity and DSP of COPD patients, and compare the effectiveness evaluation of DSP and post-SpO2.
Method: This study is a retrospective study, and 139 COPD patients from Shuang Ho Hospital, Ministry of Health and Welfare (New Taipei, Taiwan) were enrolled. HRCT, pulmonary function tests, 6 minute walking test, blood test, acute exerbation frequency were collected from subjects, than low DSP group was seperated by DSP 290m%. Pearson’s correlation was used for correlation between DSP and emphysema severity, and Logistic regression analysis was used for odds ratio. ROC curve was used to analysis specificity and sensitivity of DSP and EID to pulmonary emphysema or acute exacerbation.
Results: Low DSP group was statistical significant on age, mMRC score, CAT score, AE frequency, pulmonary function tests and 6MWT compared with high DSP group. Besides, low DSP group with severe pulmonary emphysema had much higher LAA% than control group, and its pulmonary function test and COPD symptoms scale performed poorly comparatively. Pearson’s correlation showed that both DSP and post-SpO2 are correlated with mMRC, AE frequency, low attenuation area (LAA), pulmonary function tests, 6-minute walking test, besides, DSP was also correlated with sex, CAT and lymphocytes. Logistic regression analysis showed that DSP influenced LAA not as much as post-SpO2. However, ROC curves showed that DSP may be considered to distinguish pulmonary emphysema severity than using post-SpO2.
Conclusion: This study shows that DSP is negatively correlated with pulmonary emphysema severity, and severe pulmonary emphysema patients, whose DSP is lower than 290m%, may perform worse on pulmonary function test and 6-minute walking test than whose DSP is higher, and respiratory symptoms such as dyspnea is much severe. DSP may evaluate patients’ emphysema severity better than the post-SpO2. |
