COVID後期におけるCOPD増悪・低酸素血症・高炭酸ガス血症性呼吸不全・続発性肺動脈性肺高血圧症患者への温熱ヘリオックス・一酸化窒素・分子状水素の複合使用の有効性と安全性
This randomized, parallel-group, controlled study enrolled 100 patients (52 male, 48 female) who had experienced SARS-CoV-2 pneumonia and subsequently developed COPD exacerbation (GOLD evidence levels C and D) complicated by hypoxemic-hypercapnic respiratory failure and secondary pulmonary arterial hypertension. Participants were allocated to five groups receiving various combinations of thermal heliox (t-He/O₂), nitric oxide (NO), and molecular hydrogen (H₂) alongside non-invasive ventilation and standard pharmacotherapy. The group receiving all three gases sequentially demonstrated superior outcomes across multiple parameters—including pulmonary gas exchange, acid-base balance, hemodynamics, shunt fraction, and exercise tolerance—compared with groups receiving individual gases or standard care alone. Reductions in hypoxemia and hypercapnia, improvements in vascular endothelial function, and restoration of metabolic indices were observed. No safety concerns were identified with the combined gas regimen.
Sequential administration of H₂, NO, and thermal heliox is proposed to normalize pulmonary gas exchange, increase oxygen delivery to tissues, reduce intrapulmonary shunt fraction, improve vascular endothelial function, and restore metabolic homeostasis through complementary pathophysiological mechanisms.
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/40327618