Hydrogen Gas Protects Brain After Cardiac Arrest in Rats
- Authors
- Jianjie Wang, Yiming Shen, Jingru Li, Bihua Chen, Changlin Yin, Yongqin Li
- Journal
- Frontiers in Neurology
- Year
- 2022
- DOI
- 10.3389/fneur.2022.996112
- Study Type
- Rat
- Outcome
- Positive
- Peer Reviewed
- Yes
- Country
- China
- Health Condition
- Cardiac Arrest
- Body System
- Cardiovascular
TL;DR
Breathing in a mixture of 2% hydrogen and high levels of oxygen significantly improves survival and brain function in rats after a cardiac arrest, regardless of their body temperature.
Key Finding
In rats recovering from cardiac arrest, breathing 2% hydrogen combined with high oxygen concentrations (50% or 98%) significantly improved 96-hour survival rates and reduced neurological deficits compared to standard oxygen alone.
Summary
Researchers studied whether hydrogen gas could protect the brain after cardiac arrest in rats. They compared different mixtures of oxygen and hydrogen given to rats after CPR. Rats that received hydrogen combined with high oxygen levels (50% or 98%) had better survival rates and fewer neurological problems than rats breathing regular air, suggesting hydrogen may help reduce brain damage after cardiac arrest.
Practical Takeaway
This early evidence from rat studies suggests hydrogen gas combined with high oxygen may help protect the brain after cardiac arrest. However, this is animal research only, and it's unclear whether these results would apply to humans or what the optimal oxygen and hydrogen combinations would be for clinical use. Much more research is needed before any conclusions can be drawn for human patients.
Abstract
BackgroundPost-cardiac arrest (CA) brain injury is the main cause of death in patients resuscitated from CA. Previous studies demonstrated that hydrogen inhalation mitigates post-CA brain injury. However, factors affecting the efficacy of hydrogen remain unknown. In the present study, we investigated the influence of oxygen concentration and targeted temperature on neuroprotective effect in a CA rat model of ventricular fibrillation (VF).MethodsCardiopulmonary resuscitation (CPR) was initiated after 7 min of untreated VF in adult male Sprague–Dawley rats. Immediately following successful resuscitation, animals were randomized to be ventilated with 21% oxygen and 79% nitrogen (21%O2); 2% hydrogen, 21% oxygen, and 77% nitrogen (2%H2 + 21%O2); 2% hydrogen, 50% oxygen, and 48% nitrogen (2%H2 + 50%O2); or 2% hydrogen and 98% oxygen (2%H2 + 98%O2) for 3 h. For each group, the target temperature was 37.5°C for half of the animals and 35.0°C for the other half.ResultsNo statistical differences in baseline measurements and CPR characteristics were observed among groups. For animals with normothermia, 2%H2 + 50%O2 (123 [369] vs. 500 [393], p = 0.041) and 2%H2 + 98%O2 (73 [66] vs. 500 [393], p = 0.002) groups had significantly lower neurological deficit scores (NDSs) at 96 h and significantly higher survival (75.0 vs. 37.5%, p = 0.033 and 81.3 vs. 37.5%, p = 0.012) than 21%O2 group. For animals with hypothermia, no statistical difference in NDS among groups but 2%H2 + 98%O2 has significantly higher survival than the 21%O2 group (93.8 vs. 56.3%, p = 0.014).ConclusionIn this CA rat model, inhaling 2% hydrogen combined with a high concentration of oxygen improved 96-h survival, either under normothermia or under hypothermia.