2%水素ガス混合気体を用いた未改造人工呼吸器の性能評価
This experimental study assessed whether four unmodified mechanical ventilators could accurately deliver 2% H2 gas mixtures across neonatal-to-adult ventilator settings using a closed test circuit. The Maquet Servo-i, Servo-u, and Dräger Evita Infinity V500 all demonstrated tidal volume and FiO2 delivery within ±10% bias compared with set values, and each passed pre-use safety checks. In contrast, the Dräger Babylog VN500 showed a mean tidal volume bias of −89.2% (95% CI −107.0 to −71.3), attributed to its hot-wire anemometry flow sensor and elevated operating temperature, which are incompatible with the physical properties of H2. These findings suggest that certain adult and pediatric ventilators can administer 2% H2 mixtures without hardware modification, whereas neonatal devices employing hot-wire sensors may require alternative approaches.
H2 gas possesses antioxidant, anti-inflammatory, and anti-apoptotic properties relevant to ischemia-reperfusion injury. This study examined device compatibility for clinical H2 delivery rather than biological mechanisms directly.
For inhalation applications of molecular hydrogen, the lower flammability limit (LFL) deserves careful handling. The classical 4% figure applies to closed-system mixtures; the practical inhalation-environment threshold is 10%. Even pure-hydrogen output (the UFL 75% paradox) passes through the flammable range at the air–gas boundary. High-concentration (66% / 100%) inhalers are documented in the Japanese Consumer Affairs Agency accident-information database and are not recommended.
See also:
https://h2-papers.org/en/papers/39969918