CPR時間を延長することにより生存率が上昇する(RESS[Resuscitation Science Symposium] Abstract 154）

CPRを38分以上行うことにより心停止後の生存および正常な脳機能を保持する確率が改善する

CPR for 38 minutes or longer improves chance of a person surviving cardiac arrest and having normal brain function

CPRを38分以上行うことにより患者が心停止後生存する確率および心停止後生存した患者が正常な脳機能を保持する確率が改善する可能性があるとのスタディ結果が2013年American Heart Association学会で発表された。日本における全ての院外心停止症例を追跡したレジストリを用いて研究者らは、患者が虚脱してから心拍再開までに経過した時間、および1か月後に脳機能がどの程度維持されていたかを調査した。意識清明で通常の活動に復帰できる場合や、中等度の障害を有するがパートタイムで働ける程度であったり独立して日常活動に参加できたりする場合は、生存者が神経学的に良好と判断された。虚脱してから心拍再開までの時間は、予後が良好であった者において13分であったのと比較し、重度の脳障害を負った者においては21分であった。脳の予後が良好であることと虚脱から心拍再開までの時間との相関に基づき研究者らは、CPRを38分以上継続することが推奨されると算定した。どの時点においてでも、自己心拍が再開した場合にはCPRを継続することが適切であろうと筆者らは述べている。

Performing CPR for 38 minutes or longer can improve a patient's chance of surviving cardiac arrest, according to a study presented at the American Heart Association's Scientific Sessions 2013. Sustaining CPR that long also improves the chances that survivors will have normal brain function, researchers said.

About 80 percent of cardiac arrests occur outside of a hospital each year, and fewer than 10 percent survive, according to the American Heart Association.

Research has found that early return of spontaneous circulation is important for people to survive cardiac arrest with normal brain function. But little research has focused on the period between cardiac arrest and any return of spontaneous circulation.

Using a massive registry tracking all out-of-hospital cardiac arrests in Japan in 2005-11, researchers studied how much time passed between survivors' collapse and the return of spontaneous circulation, and how well brain function was preserved a month later.

Survivors were considered to have fared well neurologically if they were alert and able to return to normal activities, or if they had moderate disability but were well enough to work part-time in a sheltered environment or take part in daily activities independently.

The time between collapse and return of spontaneous circulation for those who fared well was 13 minutes compared to about 21 minutes for those who suffered severe brain disability, said Ken Nagao, M.D., Ph.D., professor and director-in-chief of the Department of Cardiology, CPR and Emergency Cardiovascular Care at Surugadai Nihon University Hospital in Tokyo.

After adjusting for other factors that can affect neurological outcomes, researchers found that the odds of surviving an out-of-hospital cardiac arrest without severe brain damage dropped 5 percent for every 60 seconds that passed before spontaneous circulation was restored.

Based on the relationship between favorable brain outcomes and the time from collapse to a return of spontaneous circulation, the researchers calculated that CPR lasting 38 minutes or more was advisable.

"It may be appropriate to continue CPR if the return of spontaneous circulation occurs for any period of time," said Nagao.

The 2010 AHA Guidelines for CPR and ECC advise bystanders to perform CPR until emergency crews arrive.

The Japanese Circulation Society Resuscitation Science Study group conducted the study.

Co-authors are Eizo Tachibana, M.D., Ph.D.; Tukasa Yagi, M.D., Ph.D.; Naohiro Yonemoto, Dr.P.H.; Morimasa Takayama, M.D., Ph.D.; Hiroshi Nogoni, M.D., Ph.D.; Shinichi Shirai, M.D., Ph.D.; and Takeshi Kimura, M.D., Ph.D. Author disclosures are on the abstract.