Hydrogen Gas Improves Brain Recovery After Cardiac Arrest in Rats
- Authors
- Kei Hayashida, Motoaki Sano, Naomi Kamimura, Takashi Yokota, Masaru Suzuki, Shigeo Ohta, Keiichi Fukuda, Shingo Hori
- Journal
- Circulation
- Year
- 2014
- DOI
- 10.1161/CIRCULATIONAHA.114.011848
- Study Type
- Rat
- Outcome
- Positive
- Peer Reviewed
- Yes
- Country
- Japan
- Health Condition
- Cardiac Arrest
- Body System
- Cardiovascular
TL;DR
Starting hydrogen gas inhalation right after a rat's heart starts beating again, with or without cooling therapy, improves survival and brain health after cardiac arrest.
Key Finding
Rats that received both hydrogen inhalation and targeted cooling therapy after cardiac arrest had an 85.7% survival rate at 7 days, compared to 38.4% in untreated controls, with the combined treatment showing superior neurological recovery compared to cooling alone.
Summary
Researchers studied whether inhaling hydrogen gas could help rats recover from cardiac arrest (when the heart stops beating). After the rats' hearts restarted, some received hydrogen gas mixed with their breathing air, some received cooling therapy (a standard treatment), some received both, and some received neither. Rats that received both hydrogen and cooling therapy had the best survival rates and the least brain damage, suggesting that hydrogen gas may enhance recovery when added to existing cardiac arrest treatments.
Practical Takeaway
This rat study suggests hydrogen gas may have neuroprotective potential as an add-on to standard cardiac arrest treatment, but these results cannot yet be applied to humans. Human clinical trials would be needed to determine if this approach is safe and effective in cardiac arrest patients.
Abstract
Background— We have previously shown that hydrogen (H 2 ) inhalation, begun at the start of hyperoxic cardiopulmonary resuscitation, significantly improves brain and cardiac function in a rat model of cardiac arrest. Here, we examine the effectiveness of this therapeutic approach when H 2 inhalation is begun on the return of spontaneous circulation (ROSC) under normoxic conditions, either alone or in combination with targeted temperature management (TTM). Methods and Results— Rats were subjected to 6 minutes of ventricular fibrillation cardiac arrest followed by cardiopulmonary resuscitation. Five minutes after achieving ROSC, post–cardiac arrest rats were randomized into 4 groups: mechanically ventilated with 26% O 2 and normothermia (control); mechanically ventilated with 26% O 2 , 1.3% H 2 , and normothermia (H 2 ); mechanically ventilated with 26% O 2 and TTM (TTM); and mechanically ventilated with 26% O 2 , 1.3% H 2 , and TTM (TTM+H 2 ). Animal survival rate at 7 days after ROSC was 38.4% in the control group, 71.4% in the H 2 and TTM groups, and 85.7% in the TTM+H 2 group. Combined therapy of TTM and H 2 inhalation was superior to TTM alone in terms of neurological deficit scores at 24, 48, and 72 hours after ROSC, and motor activity at 7 days after ROSC. Neuronal degeneration and microglial activation in a vulnerable brain region was suppressed by both TTM alone and H 2 inhalation alone, with the combined therapy of TTM and H 2 inhalation being most effective. Conclusions— H 2 inhalation was beneficial when begun after ROSC, even when delivered in the absence of hyperoxia. Combined TTM and H 2 inhalation was more effective than TTM alone.