Rehabilitation program of post-COVID-19 syndrome with the use of nitric oxide and molecular hydrogen

Рost-COVID-19 syndrome (PS) is one of the medical and social problem. According to WHO, 10–20% of COVID-19 patients suffer from PS. The use of medical gases – inhaled nitric oxide (iNO) and molecular hydrogen (iH₂) – may influence on the mechanisms of development PC.

Aim. To evaluate the safety and efficacy of the combined inhalation of NO and H₂ (iNO/iH₂) in patients with respiratory manifestations of PS.

Materials and methods. 34 patients with PS (11 men/23 women, 60.0±11.7 years) were included in the prospective open-label controlled study in parallel groups: the main group (n=17) received iNO/iH₂ for 90 minutes once a day for 10 days (concentration of NO 60 ppm, H₂<4% in the gas mixture), the control group (n=17) didn’t receive inhalations. The period from the confirmation of COVID-19 to the start of the study was 641.8±230.5 days. The groups did not differ in the baseline parameters. The clinical symptoms (from the self-observation diary and mMRC questionnaires, "dyspnea language"), FAS, HADS, SF-36 scores, 6-minute walk test, the blood serum parameters of oxidative stress, the dynamics of the microcirculation in the eye bulbar conjunctiva were evaluated. The individual dose of iNO has chosen during a 15-minute test (the positive dynamics of the microcirculation have indicated that the dose was selected correctly).

Results. The decrease the symptoms severity, such as dyspnea, cough, fatigue and palpitations (p<0.005), the increase in SF-36 questionnaire scores (p=0.006) and a reducing of FAS score (p=0.001), as well as the anxiety component of HADS (p=0.02) were revealed at the end of treatment in the main group compared to the control group. We observed an improvement in distance walked (p=0.01) and the values SpO₂ (p=0.04) in 6-minute walk test, the increase in the volumetric blood flow velocity in venules (p<0.001), and the date in oxidative damage (p<0.001) and antioxidant activity (p=0.03) parameters in the blood serum.

Conclusion. The results of the study demonstrate clinical efficacy iNO/iH₂ on clinical indicators, parameters of oxidative stress and microcirculation in patients with PS.