Yamamoto, Ryo

写真a

Affiliation

School of Medicine, Department of Emergency and Critical Care Medicine (Shinanomachi)

Position

Instructor
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Career 【 Display / hide 】

  • 2006.04
    -
    2008.03

    東京都済生会中央病院, 初期研修医

  • 2006.04
    -
    2008.03

    東京都済生会中央病院, 初期研修医

  • 2008.04
    -
    2012.03

    Keio University School of Medicine, Department of Emerfency and Critical Care Medicine, Resident

  • 2008.04
    -
    2012.03

    Keio University School of Medicine, Department of Emerfency and Critical Care Medicine, Resident

  • 2012.04
    -
    2015.04

    済生会横浜市東部病院, 救急科, 医員

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Academic Background 【 Display / hide 】

  • 2000.04
    -
    2006.03

    Keio University, School of Medicine

  • 2000.04
    -
    2006.03

    Keio University, School of Medicine

    University, Graduated

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Academic Degrees 【 Display / hide 】

  • 学士（医学）, Keio University, Coursework, 2006.03

  • 博士（医学）, Keio University, Dissertation, 2019.05

    Hydrogen gas distribution in organs after inhalation: Real-time monitoring of tissue hydrogen concentration in rat.

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Licenses and Qualifications 【 Display / hide 】

  • ECFMG certification, 2011.07

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Research Areas 【 Display / hide 】

  • Life Science / Emergency medicine

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Books 【 Display / hide 】

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Papers 【 Display / hide 】

  • Early symptoms preceding post-infectious irritable bowel syndrome following COVID-19: a retrospective observational study incorporating daily gastrointestinal symptoms

    Yamamoto R., Yamamoto A., Masaoka T., Homma K., Matsuoka T., Takemura R., Wada M., Sasaki J., Kanai T., Amagai M., Saya H., Nishihara H.

    BMC Gastroenterology (BMC Gastroenterology)  23 ( 1 ) 108 2023.12

    　View Summary

    Background: Intestinal microinflammation with immune dysfunction due to severe acute respiratory syndrome coronavirus 2 reportedly precipitates post-infectious irritable bowel syndrome. This study aimed to elucidate potential risk factors for subsequent development of irritable bowel syndrome, hypothesizing that it is associated with specific symptoms or patient backgrounds. Methods: This single-center retrospective observational study (2020–2021) included adults with confirmed coronavirus disease requiring hospital admission and was conducted using real-world data retrieved from a hospital information system. Patient characteristics and detailed gastrointestinal symptoms were obtained and compared between patients with and without coronavirus disease-induced irritable bowel syndrome. Multivariate logistic models were used to validate the risk of developing irritable bowel syndrome. Moreover, daily gastrointestinal symptoms during hospitalization were examined in patients with irritable bowel syndrome. Results: Among the 571 eligible patients, 12 (2.1%) were diagnosed with irritable bowel syndrome following coronavirus disease. While nausea and diarrhea during hospitalization, elevated white blood cell count on admission, and intensive care unit admission were associated with the development of irritable bowel syndrome, nausea and diarrhea were identified as risk factors for its development following coronavirus disease, as revealed by the adjusted analyses (odds ratio, 4.00 [1.01–15.84] and 5.64 [1.21–26.31], respectively). Half of the patients with irritable bowel syndrome had both diarrhea and constipation until discharge, and constipation was frequently followed by diarrhea. Conclusions: While irritable bowel syndrome was rarely diagnosed following coronavirus disease, nausea and diarrhea during hospitalization precede the early signs of irritable bowel syndrome following coronavirus disease.

  • Hyperoxia for accidental hypothermia and increased mortality: a post-hoc analysis of a multicenter prospective observational study

    Yamamoto R., Yoshizawa J., Takauji S., Hayakawa M., Sasaki J.

    Critical Care (Critical Care)  27 ( 1 ) 131 2023.12

    ISSN  13648535

    　View Summary

    Background: Supraphysiologic oxygen administration causes unfavorable clinical outcomes in various diseases, including traumatic brain injury, post–cardiac arrest syndrome, and acute lung injury. Accidental hypothermia is a critical illness that reduces oxygen demands, and excessive oxygen is likely to emerge. This study aimed to determine whether hyperoxia would be associated with increased mortality in patients with accidental hypothermia. Methods: A post-hoc analysis of a nationwide multicenter prospective observational study (ICE-CRASH study) on patients with accidental hypothermia admitted in 2019–2022 was conducted. Adult patients without cardiac arrest whose core body temperature was < 32 °C and whose arterial partial pressure of oxygen (PaO2) was measured at the emergency department were included. Hyperoxia was defined as a PaO2 level of 300 mmHg or higher, and 28-day mortality was compared between patients with and without hyperoxia before rewarming. Inverse probability weighting (IPW) analyses with propensity scores were performed to adjust patient demographics, comorbidities, etiology and severity of hypothermia, hemodynamic status and laboratories on arrival, and institution characteristics. Subgroup analyses were conducted according to age, chronic cardiopulmonary diseases, hemodynamic instability, and severity of hypothermia. Results: Of the 338 patients who were eligible for the study, 65 had hyperoxia before rewarming. Patients with hyperoxia had a higher 28-day mortality rate than those without (25 (39.1%) vs. 51 (19.5%); odds ratio (OR) 2.65 (95% confidence interval 1.47–4.78); p < 0.001). IPW analyses with propensity scores revealed similar results (adjusted OR 1.65 (1.14–2.38); p = 0.008). Subgroup analyses showed that hyperoxia was harmful in the elderly and those with cardiopulmonary diseases and severe hypothermia below 28 °C, whereas hyperoxia exposure had no effect on mortality in patients with hemodynamic instability on hospital arrival. Conclusions: Hyperoxia with PaO2 levels of 300 mmHg or higher before initiating rewarming was associated with increased 28-day mortality in patients with accidental hypothermia. The amount of oxygen to administer to patients with accidental hypothermia should be carefully determined. Trial Registration: The ICE-CRASH study was registered at the University Hospital Medical Information Network Clinical Trial Registry on April 1, 2019 (UMIN-CTR ID, UMIN000036132).

  • Cushing Index Based on Cushing Signs to Predict In-Hospital Death and Early Intervention for Minor Head Injury.

    Matsumura K, Yamamoto R, Namiki J, Takemura R, Sasaki J

    Journal of neurotrauma  2023.07

    ISSN  0897-7151

  • A CASE OF TRAUMATIC RETROPHARYNGEAL HEMATOMA WITH DELAYED UPPER AIRWAY STENOSIS

    OSHIMA Chiho, YAMAMOTO Ryo, NISHIDA Yusho, OHNO Soichiro, UDAGAWA Kazuhiko, KURIHARA Tomohiro, SASAKI Junichi

    Journal of the Japanese Association for the Surgery of Trauma (The Japanese Association for the Surgery of Trauma)  37 ( 3 ) 319 - 323 2023.07

    ISSN  13406264

    　View Summary

    <p>　　A 76-year-old male was transported by ambulance to our hospital following a fall injury after drinking. Cervical CT images showed a retropharyngeal hematoma with no symptoms related to upper airway stenosis. On the 5th day after the injury, stridor appeared and oxygenation decreased. Bronchoscopy showed airway stenosis by posterior wall bulging due to retropharyngeal hematoma. The patient was immediately intubated using bronchoscopy, and respiratory condition and hypoxia improved. The patient was extubated on the 12th day and discharged to home on the 46th day. Although retropharyngeal hematoma is an uncommon injury, it is extremely rare that upper airway stenosis rapidly develops due to exaggeration of retropharyngeal hematoma on the 5th day after mild fall injury without any symptoms on hospital arrival. Extended closed observation is needed even for patients presenting without any symptoms on arrival.</p>

  • Healthcare costs for hospitalized COVID-19 patients in a Japanese university hospital: a cross-sectional study.

    Shunsuke Uno, Rei Goto, Kimiko Honda, Machiko Tokuda, Hirofumi Kamata, Shotaro Chubachi, Ryo Yamamoto, Yukio Sato, Koichiro Homma, Sho Uchida, Ho Namkoong, Yoshifumi Uwamino, Junichi Sasaki, Koichi Fukunaga, Naoki Hasegawa

    Cost effectiveness and resource allocation : C/E 21 ( 1 ) 43 - 43 2023.07

    ISSN  1478-7547

    　View Summary

    BACKGROUND: A health-economic evaluation related to COVID-19 is urgently needed to allocate healthcare resources efficiently; however, relevant medical cost data in Japan concerning COVID-19 are scarce. METHODS: This cross-sectional study investigated the healthcare cost for hospitalized COVID-19 patients in 2021 at Keio University Hospital. We calculated the healthcare costs during hospitalization using hospital claims data and investigated the variables significantly related to the healthcare cost with multivariable analysis. RESULTS: The median healthcare cost per patient for the analyzed 330 patients was Japanese yen (JPY) 1,304,431 (US dollars ~ 11,871) (interquartile range: JPY 968,349-1,954,093), and the median length of stay was 10 days. The median healthcare cost was JPY 798,810 for mild cases; JPY 1,113,680 for moderate I cases; JPY 1,643,909 for moderate II cases; and JPY 6,210,607 for severe cases. Healthcare costs increased by 4.0% for each additional day of hospitalization; 1.26 times for moderate I cases, 1.64 times for moderate II cases, and 1.84 times for severe cases compared to mild cases; and 2.05 times for cases involving ICU stay compared to those not staying in ICU. CONCLUSIONS: We clarified the healthcare cost for hospitalized COVID-19 patients by severity in a Japanese university hospital. These costs contribute as inputs for forthcoming health economic evaluations for strategies for preventing and treating COVID-19.

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Papers, etc., Registered in KOARA 【 Display / hide 】

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Reviews, Commentaries, etc. 【 Display / hide 】

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Presentations 【 Display / hide 】

  • 【レジデントが知っておくべき敗血症診療のポイント&ピットフォール】ステロイド・IVIG治療のポイント　補助療法としての効果は?

    山元 良, 藤島 清太郎

    月刊レジデント, 

    2023.06
    , 

    (株)医学出版

    　View Summary

    ＜Point(1)＞敗血症において,ステロイド治療の適応を説明できる.＜Point(2)＞敗血症に投与するステロイドの種類・量を説明できる.＜Point(3)＞IVIGとはどんな治療薬なのかを説明できる.＜Point(4)＞敗血症において,IVIGの適応を説明できる.(著者抄録)

  • 【徹底ガイド　重症感染症のすべて-研修医からの質問302-】感染症の診断・治療・病態　消毒薬の効果と限界

    堀越 雄一郎, 山元 良, 佐々木 淳一

    救急・集中治療, 

    2023.05
    , 

    (株)総合医学社

    　View Summary

    ＜ここがポイント!＞▼医療関連感染症は医療行為を介して罹患する感染症のことであり,いまだ高い有病率を認め,患者の健康のみならず社会への経済的影響も重大である.▼医療関連感染症を防ぐ手段として,正しい方法で行う手指衛生は非常に重要である.▼手指衛生に用いる消毒薬の種類を認知し,適切な種類と濃度をもって手指衛生を実施することが重要である.▼消毒薬を使用する際には,消毒薬への感受性低下の可能性を認識し,適切な濃度と量を用いることを意識する.▼消毒薬を用いた手指衛生を実施すべきタイミングを理解し,診療中に正しく実施することが重要である.(著者抄録)

  • 重症外傷患者に対する,より安全なCT撮影　ショックを伴う外傷患者における搬送時の血圧変動とCT撮影が予後に与える影響

    松岡 義, 山元 良, 佐藤 幸男, 佐々木 淳一

    日本外傷学会雑誌, 

    2023.05
    , 

    (一社)日本外傷学会

  • 重症外傷患者に対する,より安全なCT撮影　重症外傷に対する迅速CT　riskを上回るbenefitの検証

    山元 良, 前島 克哉, 船曵 知弘, 佐々木 淳一

    日本外傷学会雑誌, 

    2023.05
    , 

    (一社)日本外傷学会

  • 大腸穿孔における術前予後予測スコアの算出と術式選択への応用　EPPoC:Early Prediction for Prognosis of Colorectal perforation Score

    松岡 義, 山元 良, 小林 健二, 篠崎 浩治, 佐々木 淳一

    日本外科学会定期学術集会抄録集, 

    2023.04
    , 

    (一社)日本外科学会

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

  • 間葉系幹細胞培養上清液による幹細胞増殖を介した急性期臓器虚血再灌流障害の治療開発

    2024.04
    -
    2027.03

    基盤研究(C), Principal investigator

  • 腸管虚血に対する水素ガス吸入療法

    2022.04
    -
    2024.03

    MEXT,JSPS, Grant-in-Aid for Scientific Research, 山元 良, 若手研究, Principal investigator

    　View Summary

    本研究の目的は、重要課題であるにも関わらず特異的治療薬の存在しない腸管虚血に対する新規治療を見出すことである。研究代表者は、以前より精力的に〝水素ガス吸入療法〟に関する研究を行い、心停止後症候群に対する本邦初のランダム化比較臨床試験の実施や、吸入した水素ガスが血流に依存し体内分布する事実の解明に至った。さらに、水素ガス吸入が腸管粘膜の幹細胞の保護作用を持つ可能性を見出している。本研究は、ガス吸入という独創性の高い治療開発研究であり、すでに人体に無害であることが証明されているガスを利用することから、実現可能性も極めて高いといえる。

  • 汎発性腹膜炎を伴う上部消化管穿孔に対する術式選択支援システムの開発：急性腹症ガイドラインのための新たなエビデンスの創出

    2021.07
    -
    Present

    日本腹部救急医学会, 2021年度消化器外科領域NCD新規研究, Research grant, Principal investigator

  • Optimal Tentative Abdominal Closure for Open Abdomen (OPTITAC) trial

    2020.11
    -
    Present

    日本腹部救急医学会, 日本腹部救急医学会プロジェクト研究, Research grant, Principal investigator

  • 重症COVID-19肺炎に対する水素ガス吸入療法

    2020.06
    -
    2021.03

    国立研究開発法人 日本医療研究開発機構, ウイルス等感染症対策技術開発事業, Research grant, Coinvestigator(s)

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Awards 【 Display / hide 】

  • The 35th Japan Shock Society General Meeting, President Award

    2021.05, Japan Shock Society

    Type of Award： Award from Japanese society, conference, symposium, etc.

  • The 35th Japan Shock Society General Meeting, President Award

    2021.05, Japan Shock Society

    Type of Award： Award from Japanese society, conference, symposium, etc.

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Courses Taught 【 Display / hide 】

  • LECTURE SERIES, EMERGENCY MEDICINE

    2024

  • LECTURE SERIES, EMERGENCY MEDICINE

    2023

  • LECTURE SERIES, EMERGENCY MEDICINE

    2022

  • LECTURE SERIES, EMERGENCY MEDICINE

    2021

  • LECTURE SERIES, EMERGENCY MEDICINE

    2020

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Courses Previously Taught 【 Display / hide 】

  • LECTURE SERIES, EMERGENCY MEDICINE

    Keio University

    2023.04
    -
    2024.03

  • LECTURE SERIES, EMERGENCY MEDICINE

    Keio University

    2022.04
    -
    2023.03

  • LECTURE SERIES, EMERGENCY MEDICINE

    Keio University

    2021.04
    -
    2022.03

  • LECTURE SERIES, EMERGENCY MEDICINE

    Keio University

    2020.04
    -
    2021.03

  • LECTURE SERIES, EMERGENCY MEDICINE

    Keio University

    2019.04
    -
    2020.03

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Memberships in Academic Societies 【 Display / hide 】

  • 日本熱傷学会, 

    2013
    -
    Present

  • 日本熱傷学会, 

    2013
    -
    Present

  • 日本消化器外科学会, 

    2009.01
    -
    Present

  • 日本消化器外科学会, 

    2009.01
    -
    Present

  • Society of Critical Care Medicine, 

    2008
    -
    Present

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Committee Experiences 【 Display / hide 】

  • 2021.05
    -
    Present

    Japan CDC創設に関する委員会 新型コロナウイルス感染症の情報発信ワーキンググループ, 日本医学会連合

  • 2021.05
    -
    Present

    Japan CDC創設に関する委員会 新型コロナウイルス感染症の情報発信ワーキンググループ, 日本医学会連合

  • 2021.05
    -
    Present

    Japan CDC創設に関する委員会 新型コロナウイルス感染症の情報発信ワーキンググループ, 日本医学会連合

  • 2020.09
    -
    Present

    日本版敗血症診療ガイドライン2020特別委員会　COVID-19対策タスクフォース, 日本救急医学会・日本集中治療学会

  • 2020.09
    -
    Present

    国際委員会, 日本外傷学会

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