Subjects in the experimental arm and the control arm will receive hydrogen-oxygen mixed gas inhalation (Hydrogen-Oxygen Generator with Nebulizer, AMS-H-03, output: 3 L/min (hydrogen concentration: 66.7%, oxygen concentration: 33.3%)) and oxygen inhalation (OLO-1 Medical Molecular Sieve Oxygen Generator, output: 3 L/min (oxygen concentration: 33.3%), Shanghai Ouliang Medical Devices Co., Ltd.), respectively; the treatment duration will not be less than 8 hours per day, for 12 weeks.~Subjects in the experimental arm and the control arm will also receive other medications (excluding antiviral drugs) by the investigator as clinically indicated. Six visits are required for each subject in this study, including Visit 1 (D-7~-1), Visit 2 (D1), Visit 3 (D14±3d), Visit 4 (D28±3d), Visit 5 (D56±7d), Visit 6 (D84±7d).
This study is a multicenter, randomized, open, parallel-controlled study. Qualified subjects will randomly be assigned to the experimental arm or the control arm according to the ratio of 1:1, with age (> 60 years or ≤ 60 years), smoking status (yes/no) and forced expiratory volume in one second/prediction (FEV1 %pred > 60% or ≤ 60%) as the random stratification factors.