李 英伊¹, 孝田 雅彦¹, 下坂 拓矢¹, 佐々木 修一¹, 李 瑛^{2, 3}, 紙本 美菜子^{2, 3}, 井上 和興^{2, 3}, 朴 大昊³, 濱田 紀宏^{2, 3}, 谷口 晋一^{2, 3}

Youngee LEE¹, Masahiko KODA¹, Takuya SHIMOSAKA¹, Shuichi SASAKI¹, Young LEE^{2, 3}, Minako KAMIMOTO^{2, 3}, Kazuoki INOUE^{2, 3}, Daeho PAK³, Toshihiro HAMADA^{2, 3}, Shinichi TANIGUCHI^{2, 3}

¹日野病院組合日野病院内科, ²日野病院組合日野病院総合診療科, ³鳥取大学医学部医学科地域医療学講座

¹Department of Internal Medicine, Hino Hospital, ²Department of General Practice, Hino Hospital, ³Department of Community-based Family Medicine, Tottori University

キーワード : lung ultrasound, elderly, pneumonia, point-of-care ultrasound, mobile ultrasound scanner

目的：近年高齢者人口の増加により肺炎が増加している．肺超音波による肺炎診断能は報告されているが，高齢者肺炎に対する携帯型超音波を用いた肺point of care ultrasound（POCUS）の有用性については明らかではない．本研究の目的は携帯型超音波を用いた肺POCUSによる高齢者肺炎の診断能をCT，胸部Ｘ線の診断能と比較し，肺POCUSの臨床的有用性を明らかにすることである．対象と方法：対象は2019年1月1日より12月31日までに当院に入院し，肺炎が疑われる65歳以上の患者101例（平均年齢87.1歳，男性57例）である．携帯型超音波を用いて肺POCUSを施行し，血液検査，胸部CT，胸部Ｘ線による診断と比較した．肺POCUSによる肺炎診断はmultiple Bline（mBline）あるいはconsolidationを認めた場合とし，心原性肺水腫（心不全）の診断は両側2区域以上のmBlineを必須とし，IVC2 cm≦，呼吸性変動50％以下，右室左室比1以上，両側胸水の内1つ以上を認める場合とした．結果：101例中，総合的に肺炎と診断された症例は72例，心不全合併肺炎8例，心不全7例，その他14例であった．肺POCUSによる診断では肺炎75例で，心不全12例であった．肺POCUSと臨床診断の一致率は87％，κ値0.601（p＜0.0001）と良好であった．肺炎診断における感度はCT99％，Ｘ線92％，肺POCUS 89％の順であった．特異度はCT 85％で最も高く，肺POCUSとＸ線が78％であった．陽性的中率はCT 96％，肺POCUS 95％，Ｘ線 93％の順で，陰性的中率はCT 94％，Ｘ線74％，肺POCUS 61％の順であった．結論：携帯超音波を用いた肺POCUSによる肺炎診断能は良好でベッドサイドや在宅での利用に極めて有用であることが示唆された．

Purpose: The incidence of pneumonia is increasing with the increase in the elderly population. Although lung ultrasonography can be useful to diagnose pneumonia, there are not enough studies on the diagnostic accuracy of Lung point-of-care ultrasound (LPOCUS) in the elderly. The aim of the present study is to evaluate the diagnostic accuracy of LUS with a mobile US scanner for pneumonia in elderly patients. Method: Subjects were 101 elderly patients(mean age 87.1 years, 57 males) admitted to our hospital with suspected pneumonia between January 1 and December 31, 2019. LPOCUS was performed using a mobile ultrasound scanner, and the results were compared with those of diagnosis by blood test, chest X-ray, and chest CT. Diagnosis of pneumonia by LPOCUS was defined as multiple Blines(mBline) or consolidation. Diagnosis of heart failure required mBline in two areas or more on both sides, and presence of one or more of the following: IVC diameter 2 cm≦, respiratory variation ≦50%, ratio of right ventricle to left ventricle 1≦, and bilateral pleural effusion. Results: Of the 101 cases, 72 cases were comprehensively diagnosed with pneumonia, eight cases with heart failure with pneumonia, and seven cases with heart failure. Using LPOCUS, 75 cases were diagnosed with pneumonia and 12 cases with heart failure. The concordance rate between diagnosis by LPOCUS and clinical diagnosis was 87% (κ=0.601, p＜0.0001), which was good. The sensitivity of diagnosis of pneumonia was 99% for CT, 92% for X-ray, and 89% for LPOCUS. Specificity was highest for CT (85%), while LPOCUS and X-ray were 78%. The positive predictive value was 96% for CT, 95% for LPOCUS, and 93% for CXR, and the negative predictive value was 94% for CT, 74% for CXR, and 61% for LPOCUS. Conclusion: Bedside LPOCUS with a mobile US scanner was extremely useful for the diagnosis of pneumonia in the elderly.