Hydrogen Gas Inhalation Proves Safe for Healthy Adults in 72-Hour Study
- Authors
- Alexis R. Cole, Francesca Sperotto, James A. DiNardo, Stephanie Carlisle, Michael J. Rivkin, Lynn A. Sleeper, John N. Kheir
- Journal
- Critical Care Explorations
- Year
- 2021
- DOI
- 10.1097/CCE.0000000000000543
- Study Type
- Human
- Outcome
- Positive
- Peer Reviewed
- Yes
- Country
- United States
- Health Condition
- Ischemia-Reperfusion Injury
- Body System
- Cardiovascular
TL;DR
Breathing in hydrogen gas at certain levels seems safe for healthy adults and doesn't cause harmful effects.
Key Finding
Inhaling 2.4% hydrogen gas for up to 72 hours produced no clinically significant adverse effects in healthy adults across all measured safety parameters.
Summary
Researchers tested whether breathing hydrogen gas mixed with air is safe in healthy adults. Eight volunteers breathed 2.4% hydrogen gas through a nasal tube for 24 to 72 hours while hospitalized. The researchers monitored their heart rate, breathing, blood tests, brain function, and heart activity before and after exposure. No serious side effects occurred, and all measurements remained normal.
Practical Takeaway
This small safety study in healthy volunteers suggests that inhaled hydrogen gas at this concentration may be tolerable for extended periods, which could support future research in critically ill patients. However, this was a very small study (8 people) in healthy adults only, so it doesn't tell us whether hydrogen gas would be safe or beneficial for people with actual medical conditions.
Abstract
Ischemia-reperfusion injury is common in critically ill patients, and directed therapies are lacking. Inhaled hydrogen gas diminishes ischemia-reperfusion injury in models of shock, stroke, and cardiac arrest. The purpose of this study was to investigate the safety of inhaled hydrogen gas at doses required for a clinical efficacy study. Design: Prospective, single-arm study. Setting: Tertiary care hospital. Patients/subjects: Eight healthy adult participants. Interventions: Subjects underwent hospitalized exposure to 2.4% hydrogen gas in medical air via high-flow nasal cannula (15 L/min) for 24 (n = 2), 48 (n = 2), or 72 (n = 4) hours. Measurements and main results: Endpoints included vital signs, patient- and nurse-reported signs and symptoms (stratified according to clinical significance), pulmonary function testing, 12-lead electrocardiogram, mini-mental state examinations, neurologic examination, and serologic testing prior to and following exposure. All adverse events were verified by two clinicians external to the study team and an external Data and Safety Monitoring Board. All eight participants (18-30 yr; 50% female; 62% non-Caucasian) completed the study without early termination. No clinically significant adverse events occurred in any patient. Compared with baseline measures, there were no clinically significant changes over time in vital signs, pulmonary function testing results, Mini-Mental State Examination scores, neurologic examination findings, electrocardiogram measurements, or serologic tests for hematologic (except for clinically insignificant increases in hematocrit and platelet counts), renal, hepatic, pancreatic, or cardiac injury associated with hydrogen gas inhalation. Conclusions: Inhalation of 2.4% hydrogen gas does not appear to cause clinically significant adverse effects in healthy adults. Although these data suggest that inhaled hydrogen gas may be well tolerated, future studies need to be powered to further evaluate safety. These data will be foundational to future interventional studies of inhaled hydrogen gas in injury states, including following cardiac arrest.