Breathing Special Gases After Heart Attack May Protect Brain and Heart
- Authors
- Abbas Alshami, Sharon Einav, Markus B. Skrifvars, Joseph Varon
- Journal
- American Journal of Emergency Medicine
- Year
- 2020
- DOI
- 10.1016/j.ajem.2020.06.066
- Study Type
- clinical
- Peer Reviewed
- Yes
- Country
- United States
- Health Condition
- Cardiac Arrest
- Body System
- Cardiovascular
TL;DR
Scientists looked at whether breathing in special gases like xenon and hydrogen after someone's heart stops could help protect their brain and heart. Early research shows these gases might work, but there aren't enough tests on actual patients yet to prove it really helps.
Key Finding
Hydrogen, xenon, and nitric oxide showed both brain-protective and heart-strengthening effects in preclinical studies following cardiac arrest, with hydrogen and hydrogen sulfide uniquely preserving the most oxygen-sensitive brain region (hippocampal CA1 sector).
Summary
This review examined studies on inhaling various gases—including hydrogen, xenon, and nitric oxide—after cardiac arrest and CPR to see if they could protect the brain and heart from damage. Researchers found 27 relevant studies, mostly in animals. Several gases showed promise in laboratory studies for protecting brain tissue, with hydrogen and hydrogen sulfide being particularly effective at protecting a vulnerable brain region called the hippocampus. However, very few human studies exist, so it's unclear whether these gases actually work in real patients.
Practical Takeaway
While early laboratory evidence suggests hydrogen gas may have neuroprotective potential after cardiac arrest, this review found almost no human clinical trials. Any claims about hydrogen water or inhaled hydrogen for cardiac protection would be premature—much more human research is needed before these gases could be considered established medical treatments.
Abstract
Objective: Inhalation of noble and other gases after cardiac arrest (CA) might improve neurological and cardiac outcomes. This article discusses up-to-date information on this novel therapeutic intervention. Data sources: CENTRAL, MEDLINE, online published abstracts from conference proceedings, clinical trial registry clinicaltrials.gov, and reference lists of relevant papers were systematically searched from January 1960 till March 2019. Study selection: Preclinical and clinical studies, irrespective of their types or described outcomes, were included. Data extraction: Abstract screening, study selection, and data extraction were performed by two independent authors. Due to the paucity of human trials, risk of bias assessment was not performed DATA SYNTHESIS: After screening 281 interventional studies, we included an overall of 27. Only, xenon, helium, hydrogen, and nitric oxide have been or are being studied on humans. Xenon, nitric oxide, and hydrogen show both neuroprotective and cardiotonic features, while argon and hydrogen sulfide seem neuroprotective, but not cardiotonic. Most gases have elicited neurohistological protection in preclinical studies; however, only hydrogen and hydrogen sulfide appeared to preserve CA1 sector of hippocampus, the most vulnerable area in the brain for hypoxia. Conclusion: Inhalation of certain gases after CPR appears promising in mitigating neurological and cardiac damage and may become the next successful neuroprotective and cardiotonic interventions.