2023/03/22
Keio University School of Medicine
Tokyo Dental College
Professor Masaru Suzuki of Tokyo Dental College (Project Professor at the Keio University Global Research Institute), Senior Lecturer Koichiro Homma of the Department of Emergency and Critical Care Medicine, Keio University School of Medicine, and Associate Professor Motoaki Sano of the Division of Cardiology, Department of Internal Medicine at the same university, as part of the activities of the Keio University Global Research Institute's Center for Hydrogen Gas Medicine, conducted a multicenter, double-blind, randomized, controlled trial involving 15 domestic institutions. They demonstrated that administering 2% hydrogen-supplemented oxygen inhalation (hydrogen inhalation therapy) to patients who suffered out-of-hospital cardiac arrest and had their heartbeat restored through cardiopulmonary resuscitation but remained unconscious, reduces mortality and increases the likelihood of returning to society with restored consciousness and without sequelae.
When a person suddenly goes into cardiac arrest due to heart problems or other issues, it is not uncommon for their life to be saved and their heartbeat restored if cardiopulmonary resuscitation is performed immediately. However, organs throughout the body, including the brain, suffer significant damage because blood did not circulate while the heart was stopped. As a result, the reality is that many patients die without regaining consciousness or are left with severe sequelae. Currently, targeted temperature management is performed, but its effectiveness has not yet been established.
This research group has previously reported that in animal experiments, hydrogen gas inhalation after cardiac arrest reduces mortality and alleviates brain injury. However, whether this effect applies to humans had not yet been proven. Therefore, this time, using the most reliable research method—a double-blind, randomized, controlled trial—we administered 2% hydrogen-supplemented oxygen inhalation in addition to targeted temperature management to patients with out-of-hospital cardiac arrest to examine whether it would improve mortality rates and neurological sequelae.
Due to the ongoing COVID-19 pandemic, emergency medical services were strained, and the study was unavoidably terminated early. As a result, the target number of cases was not reached, and the study could not definitively show whether hydrogen inhalation therapy is effective. Surprisingly, however, the 90-day survival rate increased from 61% with conventional treatment to 85% with hydrogen inhalation therapy. Furthermore, it was statistically confirmed that the proportion of people who recovered without sequelae also rose from 21% to 46%. Hydrogen is considered harmless to the human body, and no side effects attributable to hydrogen were observed in this clinical trial. It is believed that its practical application could save many patients' lives.
These research findings were published in the journal eClinical Medicine on March 17, 2023 (JST).
For the full press release, please see below.