Inhalation of high concentration hydrogen gas improves short-term outcomes in a rat model of asphyxia induced-cardiac arrest
Huang L, Applegate RL II, Applegate PM, Boling W, Zhang JH. · Medical Gas Research. 2018;8(3):73–78.
Study at a glance
Preclinical
56 older male Sprague-Dawley rats subjected to nine or eleven minutes of asphyxia and cardiopulmonary resuscitation.
One hour before plus one hour after resuscitation, or two hours beginning one hour after resuscitation, in a hydrogen-treatment chamber. · The generator was described as capable of 67% H₂/33% O₂ at 2–3 L/min, but the experiment used a monitored chamber concentration of 60% H₂ without stating the actual intervention flow or chamber O₂ concentration.
One-hour pre- and post-treatment or two-hour post-treatment; neurological observations through 72 hours and survival through seven days.
Most comparisons were trends rather than statistically confirmed benefits. In the nine-minute model, neurological scores, seizures and seven-day survival did not differ significantly. In the eleven-minute model, resuscitation success, seizures and overall mortality numerically favored H₂, but none reached statistical significance; hemodynamics and body-weight changes were also largely null.
Small male-rat groups, pre-treatment has limited clinical realism, no matched chamber control, severe-model attrition after failed resuscitation, only two schedules and predominantly nonsignificant outcomes. A Loma Linda anesthesiology endowment funded the study; authors declared no conflicts and identified the commercial generator manufacturer.
What kind of evidence is this?
Preclinical
Two-experiment rat asphyxial-cardiac-arrest study comparing post-treatment with pre-plus-post treatment
Critical care and ischemia-reperfusion
Inhaled H₂
Information not yet classified
Some editorial classification fields are still pending. The source-reported outcomes and result are shown below; Hydrogenology does not infer a positive or negative signal from prose automatically.
Methods
56 older male Sprague-Dawley rats subjected to nine or eleven minutes of asphyxia and cardiopulmonary resuscitation.
Experiment I: untreated n=13, post-treatment n=13 and pre-plus-post n=12. Experiment II: untreated n=9 and pre-plus-post n=9.
One-hour pre- and post-treatment or two-hour post-treatment; neurological observations through 72 hours and survival through seven days.
One hour before plus one hour after resuscitation, or two hours beginning one hour after resuscitation, in a hydrogen-treatment chamber.
Water-electrolysis oxyhydrogen source. The chamber was monitored at 60% H₂; the exact delivered O₂ percentage was not reported, so the exposure is not relabeled as a confirmed 60:30 Brown's-gas mixture.
The generator was described as capable of 67% H₂/33% O₂ at 2–3 L/min, but the experiment used a monitored chamber concentration of 60% H₂ without stating the actual intervention flow or chamber O₂ concentration.
Not reported — the device capability of 2–3 L/min is not treated as the actual experimental flow.
Generated O₂ was co-delivered, but the exact chamber percentage and mL/min flow were not reported.
Cardiac arrest without chamber H₂ treatment; no matched chamber-gas exposure was described.
Outcomes and reported result
Return of spontaneous circulation, hemodynamics, seizures, neurological-deficit score, body weight and seven-day survival.
Most comparisons were trends rather than statistically confirmed benefits. In the nine-minute model, neurological scores, seizures and seven-day survival did not differ significantly. In the eleven-minute model, resuscitation success, seizures and overall mortality numerically favored H₂, but none reached statistical significance; hemodynamics and body-weight changes were also largely null.
The complete free PMC article, tables and figures were checked for both experiments, group allocation, exposure details, the distinction between device capability and actual flow, positive-direction trends, null findings, limitations, funding and conflicts.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Small male-rat groups, pre-treatment has limited clinical realism, no matched chamber control, severe-model attrition after failed resuscitation, only two schedules and predominantly nonsignificant outcomes. A Loma Linda anesthesiology endowment funded the study; authors declared no conflicts and identified the commercial generator manufacturer.
Experimental asphyxial cardiac arrest in rats; it does not establish neurological or survival benefit after human cardiac arrest.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 30319760 · DOI: 10.4103/2045-9912.241063
Free full article in PubMed Central.
Complete PMC article and PubMed metadata; full-text extraction checked 9 August 2026.
10 August 2026
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