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Molecular hydrogen exposure improves functional state of red blood cells in the early postoperative period: a randomized clinical study.

心肺バイパス手術における分子水素吸入が赤血球機能状態および心機能指標に与える影響:無作為化臨床試験

human randomized controlled trial inhalation positive 1.5–2%

Abstract

This randomized clinical trial enrolled 24 patients undergoing elective cardiac surgery with cardiopulmonary bypass (CPB) for acquired valve disease at a specialized cardiosurgical hospital in Nizhny Novgorod, Russia. Twelve patients inhaled 1.5–2.0% molecular hydrogen via facemask through a ventilator breathing circuit from tracheal intubation through the end of surgery, while 12 control patients received no hydrogen. Blood samples were collected at four time points: immediately after anesthesia induction, before CPB initiation, immediately after CPB termination, and 24 hours postoperatively. Compared with controls, the hydrogen group showed increased erythrocyte electrophoretic mobility, enhanced red blood cell metabolic activity, and reduced erythrocyte aggregation. Markers of oxidative stress were most markedly reduced at 24 hours after surgery. Statistically significant differences in myocardial contractile function were observed on postoperative days 1 and 3. These findings indicate that hydrogen inhalation during CPB surgery is associated with improved red blood cell functional status and a more favorable early postoperative course.

Mechanism

Molecular hydrogen is thought to reduce oxidative stress during cardiopulmonary bypass, thereby improving erythrocyte membrane charge and metabolic activity, decreasing red blood cell aggregation, and contributing to enhanced myocardial contractile function in the early postoperative period.

Bibliographic

Authors
Deryugina AV, Danilova DA, Brichkin YD, Taranov EV, Nazarov EI, Pichugin VV, et al.
Journal
Med Gas Res
Year
2023
PMID
36204784
DOI
10.4103/2045-9912.356473
PMC
PMC9555031

Tags

Delivery context

In air, molecular hydrogen is reported to be combustible across approximately **4% (LFL, lower flammability limit) to 75% (UFL, upper flammability limit)**. Among high-concentration hydrogen inhalers, 66% output sits inside this range, and even pure-hydrogen (100%) output forms a 4–75% concentration-gradient layer at the device–air boundary (the UFL 75% paradox). Engineering principle would therefore call for operation below LFL (the classical 4%); that figure, however, was measured under closed, pre-mixed, static conditions. For the open, dynamic inhalation environment, the empirical value reported in the literature is **10%**, which is the figure referenced in practice as the operating ceiling. The 66% / 100% output devices are recorded in the Japanese Consumer Affairs Agency accident-information database, and from these considerations are not recommended.

→ Evidence by delivery route

Safety notes

In air, molecular hydrogen is reported to be combustible across approximately **4% (LFL, lower flammability limit) to 75% (UFL, upper flammability limit)**. Among high-concentration hydrogen inhalers, 66% output sits inside this range, and even pure-hydrogen (100%) output forms a 4–75% concentration-gradient layer at the device–air boundary (the UFL 75% paradox). Engineering principle would therefore call for operation below LFL (the classical 4%); that figure, however, was measured under closed, pre-mixed, static conditions. For the open, dynamic inhalation environment, the empirical value reported in the literature is **10%**, which is the figure referenced in practice as the operating ceiling. The 66% / 100% output devices are recorded in the Japanese Consumer Affairs Agency accident-information database, and from these considerations are not recommended.

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