[The combined use of inhaled nitric oxide and molecular hydrogen in patients with post-COVID-19 syndrome].

Abstract

Background: Medical gases, inhaled nitric oxide (iNO) and molecular hydrogen (iH2), have been used in the therapy for various medical conditions. When combined, these gases have shown to be more effective and safer for patients, and may become a promising treatment option for various diseases рost-COVID-19 syndrome (PS).

Aim: To compare the efficacy and safety of combined therapy iNO/iH₂ with monotherapy iNO and a control group in patients with respiratory disorders during with PS.

Materials and methods: A prospective, open-label, controlled trial involving 60 patients with PS was conducted in parallel groups (the mean age of the participants was 58.1 ± 12.9 years, and the sample consisted of 18 men and 42 women). The participants were randomly assigned to 3 groups: 1 (n = 20) - iNO/iH₂ treatment; 2 (n = 20) - only iNO treatment; and 3 (n = 20) - control group. The duration of treatment was 10 days, and the treatment involved inhalation through a nasal cannula for 90 minutes (flow rate of 4 liters per minute, iH₂ concentrations < 4%, iNO - 60 pmm). Clinical outcomes were assessed using self-observation diaries, Modified Medical Research Council Dyspnea Scale questionnaires, the "Language of Dyspnea" Scale, Fatigue Assessment Scale, Hospital Anxiety and Depression Scale, and Short Form-36 Health Status Survey questionnaires. Additionally, a 6-Minute Walk Test was performed, and indicators of oxidative status in blood serum and microcirculation in the bulbar conjunctiva were measured.

Results: The course of iNO/iН₂ and iNO led to regression of the clinical manifestations of PS (dyspnea, cough, fatigue), improved the physical and psychological component of quality of life, and contributed to improvement in microcirculation (increased venule diameter and velocity) compared to the control group (p < 0.05). In combination therapy, there was an increase in distance traveled by 6-minute walk test and decrease in reactive oxygen species compared to iNO and control groups (p < 0.05). No serious adverse events were noted.

Conclusion: The study demonstrates the advantage of the iNO/iH₂ course in comparison with iNO and control in the rehabilitation program of patients with PS. The safety and effectiveness of the iNO/iH₂ course has been proven in the form of regression of clinical manifestations of PS, improvement of quality of life, exercise tolerance, microcirculation parameters, and restoration of the oxidative status of the body.