In patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), the inhalation of an oxygen/hydroxide mixture vs oxygen alone, was associated with enhanced improvement in symptoms, including breathlessness, cough, and sputum, with an acceptable safety and tolerability profile.  A prospective, randomized, double-blind, parallel-group, controlled trial ( Identifier: NCT04000451) was conducted in 10 centers in China. Results of the analysis were published in the journal Respiratory Research.

Investigators sought to explore whether use of an oxygen/hydroxide mixture was superior to the use of oxygen in patients with AECOPD. All participants had a Breathlessness, Cough, and Sputum Scale (BCSS) score of at least 6 points. Eligible individuals were assigned in a 1:1 ratio to receive either an oxygen/hydroxide mixture or oxygen therapy.

The primary efficacy endpoint was change from baseline to day 7 via BCSS score, with 0 denoting “no symptoms” and 12 denoting “severely affected.” Secondary endpoints included change in Cough Assessment Test (CAT) score, which was calculated using the CAT Questionnaire, and change in noninvasive oxygen saturation. Exploratory endpoints were evaluated as well, including change in pulmonary function (forced vital capacity [FVC], forced expiratory volume in 1 second [FEV1], and FEV1/FVC); change in arterial blood gas while breathing room air, additional oxygen inhalation, additional noninvasive ventilation, and instrument performance evaluation.

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Of the 142 individuals who were screened, a total of 108 patients were randomly selected to receive either the hydrogen/oxygen mixture (n=54; intervention group) or  oxygen (n=54; control group). The mean participant age was 69.7±7.72 years in the intervention group and 69.8±8.23 years in the control group.

The change in BCSS score in the hydrogen/oxygen arm was significantly larger than that in the oxygen arm (-5.3 points vs -2.4 points, respectively; difference, -2.75; 95% CI,

-3.27 to -2.22), meeting the criteria for superiority. Moreover, participants in the hydrogen/oxygen group reported a more significant improvement in BCSS score over time (from day 1 to day 7), compared with participants in the oxygen group (P <.0001); the time by group interaction effect was also significant (P <.0001).

Regarding CAT score, a statistically significant reduction was seen with hydrogen/ oxygen (-11.00; 95% CI, -12.60 to -9.48) compared with the reduction seen with oxygen alone (-6.00; 95% CI, -7.46 to -4.61) in the full analysis set population

(P <.001). The data in the per-protocol set population were consistent with these results as well (-11.40; 95% CI, -12.99 to -9.79 vs -5.90; 95% CI, -7.37 to -4.38, respectively; P <.001).

Changes in pulmonary function parameters, arterial blood gas, and noninvasive oxygen saturation did not differ significantly between the groups.  Adverse events were reported in 63.0% of participants in the hydrogen/oxygen group and in 77.8% of those in the oxygen group.

The investigators concluded that the findings from this study show that the use of hydrogen/oxygen therapy was feasible and well tolerated among patients with AECOPD. This intervention might have potential use as an alternative emergency strategy for patient with AECOPD.


Zheng Z-G, Sun W-Z, Hu J-Y, et al. Hydrogen/oxygen therapy for the treatment of an acute exacerbation of chronic obstructive pulmonary disease: results of a multicenter, randomized, double-blind, parallel-group controlled trial. Respir Res. 2021;22(1):149. doi:10.1186/s12931-021-01740-w