Yamamoto, Ryo

写真a

Affiliation

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

Position

Senior Assistant Professor (Non-tenured)/Assistant Professor (Non-tenured)
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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 】

  • Veno-arterial extracorporeal membrane oxygenation uses in trauma: a retrospective analysis of the Japanese nationwide trauma registry

    Akutsu T., Endo A., Yamamoto R., Yamakawa K., Suzuki K., Hoshi H., Otomo Y., Morishita K.

    BMC Emergency Medicine 24 ( 1 ) 179 2024.12

    　View Summary

    Background: Extracorporeal membrane oxygenation (ECMO) can provide temporary circulatory support and vital organ oxygenation and is potentially useful as a bridge therapy in some trauma cases. We aimed to demonstrate the characteristics and outcomes of patients with trauma treated with veno-arterial ECMO (V-A ECMO) using data from a Japanese nationwide trauma registry. Methods: This retrospective descriptive study analyzed data from the Japan Trauma Data Bank between January 2019 and December 2021. Patients with severe trauma (injury severity score [ISS] ≥ 9) and treated using V-A ECMO were assessed. Results: Among the 72,439 patients with severe trauma, 51 received V-A ECMO. Sixteen patients (31.3%) survived until hospital discharge. On hospital arrival, six (37.5%) survivors and 15 (42.9%) non-survivors experienced cardiac arrest. The median ISS for the survivor and non-survivor group was 25 (range, 25–39) and 25 (range, 17–33), respectively. Thoracic trauma was the most common type of trauma in both groups. In the non-survivor group, open-chest cardiopulmonary resuscitation, aortic cross-clamping, and resuscitative endovascular balloon occlusion of the aorta were performed in 10 (28.6%), 5 (14.3%), and 4 (11.4%) patients, respectively. However, these procedures were not performed in the survivor group. Peripheral oxygen saturation tended to be lower in the survivor group both before and upon arrival at the hospital. Conclusions: The results of this study suggest the potential benefit of V-A ECMO in some challenging trauma cases. Further studies are warranted to assess the indications for V-A ECMO in patients with trauma.

  • Use of resuscitative endovascular balloon occlusion of the aorta (REBOA) for trauma and its performance in Japan over the past 18 years: a nationwide descriptive study

    Hoshi H., Endo A., Yamamoto R., Yamakawa K., Suzuki K., Akutsu T., Morishita K.

    World Journal of Emergency Surgery 19 ( 1 ) 19 2024.12

    　View Summary

    Background: Resuscitative endovascular balloon occlusion of the aorta (REBOA) has been used to control massive hemorrhages. Although there is no consensus on the efficacy of REBOA, it remains an option as a bridging therapy in non-trauma centers where trauma surgeons are not available. To better understand the current landscape of REBOA application, we examined changes in its usage, target population, and treatment outcomes in Japan, where immediate hemostasis procedures sometimes cannot be performed. Methods: This retrospective observational study used the Japan Trauma Data Bank data. All cases in which REBOA was performed between January 2004 and December 2021 were included. The primary outcome was the in-hospital mortality rate. We analyzed mortality trends over time according to the number of cases, number of centers, severity of injury, and overall and subgroup mortality associated with REBOA usage. We performed a logistic analysis of mortality trends over time, adjusting for probability of survival based on the trauma and injury severity score. Results: Overall, 2557 patients were treated with REBOA and were deemed eligible for inclusion. The median age of the participants was 55 years, and male patients constituted 65.3% of the study population. Blunt trauma accounted for approximately 93.0% of the cases. The number of cases and facilities that used REBOA increased until 2019. While the injury severity score and revised trauma score did not change throughout the observation period, the hospital mortality rate decreased from 91.3 to 50.9%. The REBOA group without severe head or spine injuries showed greater improvement in mortality than the all-patient group using REBOA and all-trauma patient group. The greatest improvement in mortality was observed in patients with systolic blood pressure ≥ 80 mmHg. The adjusted odds ratios for hospital mortality steadily declined, even after adjusting for the probability of survival. Conclusions: While there was no significant change in patient severity, mortality of patients treated with REBOA decreased over time. Further research is required to determine the reasons for these improvements in trauma care.

  • Differences in outcomes of patients with out-of-hospital cardiac arrest treated with extracorporeal cardiopulmonary resuscitation between day-time and night-time

    Koguchi H., Takayama W., Otomo Y., Morishita K., Inoue A., Hifumi T., Sakamoto T., Kuroda Y., Senda A., Suzuki H., Tanimoto A., Kitagawa K., Katayama Y., Igarashi N., Kawano M., Kuroki Y., Umehara T., Sasaki Y., Tominaga N., Hamaguchi T., Sakai T., Abe T., Hanafusa H., Yamaoka Y., Kakizaki Y., Sakato S., Kashiwabara S., Kadoya T., Misumi K., Kobayashi T., SouYamada , Kobayashi M., Akashi N., Kuno M., Maruyama J., Kobata H., Soh M., Shirasaki K., Shiba D., Isokawa S., Uchida M., Sakurai A., Tatsukawa H., Nishikawa M., Kojima M., Kosaki R., Shimazui T., Kinoshita H., Sawada Y., Yamamoto R., Masuzawa Y., Matsumura K., Shimazaki J.

    Scientific Reports 14 ( 1 )  2024.12

    　View Summary

    Although patients who underwent night-time resuscitation for out-of-hospital cardiac arrest (OHCA) had worse clinical outcomes than those who underwent day-time resuscitation, the differences between the outcomes of patients with OHCA who underwent extracorporeal cardiopulmonary resuscitation (ECPR) in the day-time and night-time remain unclear. We analyzed data from the Study of Advanced Life Support for Ventricular Fibrillation with Extracorporeal Circulation in Japan. Patients were categorized according to whether they received treatment during the day-time or night-time. The primary outcomes were survival to hospital discharge and favorable neurological outcome at discharge, and the secondary outcomes were estimated low-flow time, implementation time of ECPR, and complications due to ECPR. A multivariate logistic regression model adjusted for confounders was used for comparison. Among the 1644 patients, the night-time patients had a significantly longer ECMO implementation time and estimated low-flow time than the day-time patients, along with a significantly higher number of complications than the day-time patients. However, the survival and neurologically favorable survival rates did not differ significantly between the groups. Thus, although patients who underwent ECPR at night had an increased risk of longer implementation time and complications, their clinical outcomes did not differ from those who underwent day-time ECPR.

  • Association between preoperative lactate level and early complications after surgery for isolated extremity fracture

    Nishida Y., Yamamoto R., Ono S., Sasaki J.

    BMC Musculoskeletal Disorders 25 ( 1 ) 314 2024.12

    　View Summary

    Background: The role of lactate level in selecting the timing of definitive surgery for isolated extremity fracture remains unclear. Therefore, we aimed to elucidate the use of preoperative lactate level for predicting early postoperative complications. Methods: This was a single-center retrospective observational study of patients with isolated extremity fracture who underwent orthopedic surgery. Patients who underwent lactate level assessment within 24 h prior to surgery were included. The incidence of early postoperative complications was compared between patients with a preoperative lactate level of ≥ 2 and < 2 mmol/L. Moreover, subgroup analyses were performed based on the time from hospital arrival to surgery and fracture type. Results: In total, 187 patients were included in the study. The incidence of postoperative complications was significantly higher in patients with a preoperative lactate level of ≥ 2 mmol/L than those with a preoperative lactate level of < 2 mmol/L. This result did not change after adjusting for age and severity. Further, a high preoperative lactate level was associated with a greater incidence of postoperative complications in patients who underwent definitive surgery within 6 h after arrival. Conclusion: A preoperative lactate level of ≥ 2 mmol/L was associated with a greater incidence of early postoperative complications in isolated extremity fractures. Nevertheless, this correlation was only observed among patients who underwent definitive fixation within 6 h after hospital arrival.

  • Prehospital endotracheal intubation for traumatic out-of-hospital cardiac arrest and improved neurological outcomes.

    Yamamoto R, Suzuki M, Takemura R, Sasaki J

    Emergency medicine journal : EMJ  2024.11

    ISSN  1472-0205

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

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Reviews, Commentaries, etc. 【 Display / hide 】

  • 重症COVID-19に対する早期挿管と死亡率の減少 多施設共同研究によるパンデミック初期の学説への挑戦

    山元 良, 垣内 大樹, 松村 一希, 本間 康一郎, 遠藤 彰, 田上 隆, 鈴木 茂利雄, 八木 雅幸, 梨木 栄作, 佐々木 淳一

    日本救急医学会雑誌 ((一社)日本救急医学会)  33 ( 10 ) 758 - 758 2022.10

    ISSN  0915-924X

  • 救急医の新たな役割 ワクチン接種計画から接種後の副反応対応まで

    佐藤 幸男, 山元 良, 宇野 俊介, 上蓑 義典, 菅原 洋子, 正木 克宜, 高橋 勇人, 関根 和彦, 福永 興壱, 長谷川 直樹, 佐々木 淳一

    日本救急医学会雑誌 ((一社)日本救急医学会)  32 ( 12 ) 1993 - 1993 2021.11

    ISSN  0915-924X

  • Reply to Swinging the pendulum in prehospital trauma mortality needs a more holistic approach.

    Yamamoto R, Suzuki M, Sasaki J

    The journal of trauma and acute care surgery (Journal of Trauma and Acute Care Surgery)  91 ( 3 ) E81 - E82 2021.09

    ISSN  21630755

  • web会議ツールを利用した救命のための侵襲的手技に関するオンライン講義の試み

    佐藤 幸男, 葉 季久雄, 金子 靖, 高詰 佳史, 山元 良, 佐々木 淳一

    日本外傷学会雑誌 ((一社)日本外傷学会)  35 ( 2 ) 152 - 152 2021.05

    ISSN  1340-6264

  • Reply to Methodological issues on developing a novel scale for prediction of delayed intubation in patients with inhalation injury

    Yamamoto R, Matsumura K, Sasaki J

    Burns (Burns)  47 ( 1 ) 258 2021.02

    Other, Joint Work,  ISSN  03054179

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Presentations 【 Display / hide 】

  • 【救うを救ける-Surgical Rescue】Surgical Rescueの実践　慶應義塾大学病院におけるSurgical Rescue

    山元 良

    救急医学, 

    2024.09
    , 

    (株)へるす出版

  • 【内科医が知っておくべきICU・ERでの薬の使い方】血液　止血製剤

    山元 良

    Medicina, 

    2024.09
    , 

    (株)医学書院

    　View Summary

    ＜文献概要＞Point　◎プロトロンビン複合体はビタミンK拮抗薬の抗凝固作用を抑制する目的として使用され,少ない容量負荷で迅速な効果発現が可能である.◎プロトロンビン複合体はワルファリン服用中の急性重篤出血あるいは緊急手術・処置を行う際に保険適用となるが,容量負荷を避けたい患者や迅速な凝固能の回復が望ましい場面に良い適応となる.◎イダルシズマブとアンデキサネット アルファは直接経口抗凝固薬(DOAC)の拮抗薬であるが,イダルシズマブはダビガトランのみ,アンデキサネット アルファはリバーロキサバン,アピキサバン,エドキサバンに対して有効である.◎トラネキサム酸は外傷患者や周術期での効果が示されてきた止血薬剤であるが,消化管出血などの内科領域の出血性疾患ではその効果は確立していない.

  • 初回手術時間がopen abdomen後の筋膜閉鎖に与える影響

    山下 幾太郎, 山元 良, 矢島 慶太郎, 松岡 義, 佐藤 幸男, 佐々木 淳一

    日本消化器外科学会総会, 

    2024.07
    , 

    (一社)日本消化器外科学会

  • ロボット支援腹腔鏡下前立腺全摘除術後に下肢コンパートメント症候群を生じ緊急減張切開術を要した1例

    村田 康彰, 松本 一宏, 山元 良, 福本 桂資郎, 安水 洋太, 田中 伸之, 武田 利和, 森田 伸也, 小坂 威雄, 水野 隆一, 浅沼 宏, 佐々木 淳一, 大家 基嗣

    泌尿器外科, 

    2024.06
    , 

    医学図書出版(株)

  • 【QQ CASES COLLECTION 100】右上腹部の一つの銃創

    山元 良

    救急医学, 

    2024.06
    , 

    (株)へるす出版

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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

    Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Principal investigator

    　View Summary

    本研究の目的は、特異的治療薬の存在しない臓器虚血再灌流障害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虚血再灌流障害に対する治療開発研究を行い、水素ガスが腸管虚血再灌流で腸粘膜幹細胞を保護することを解明した。また、虚血臓器障害急性期では再灌流による幹細胞障害が背景病態である可能性を見出し、組織再生効果が示唆された間葉系幹細胞培養上清液を用いた幹細胞保護再生治療の開発に着手している。本研究は、幹細胞そのものではなく、培養上清液によって急性期から自己幹細胞の保護増殖を図る独創性の高い治療開発研究であり、人体に無害であると証明された上清液を用いることから実現可能性も極めて高い。

  • 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

    2025

  • LECTURE SERIES, EMERGENCY MEDICINE

    2024

  • LECTURE SERIES, EMERGENCY MEDICINE

    2023

  • LECTURE SERIES, EMERGENCY MEDICINE

    2022

  • LECTURE SERIES, EMERGENCY MEDICINE

    2021

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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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