Efficacy and safety of the combined use of medical gases in patients with exacerbation of chronic obstructive pulmonary disease and secondary pulmonary arterial hypertension in the post-COVID period

The interest in medical gases for the correction of respiratory failure (RF) has been growing over recent years. However, there are virtually no scientific studies of combination therapy for exacerbation of chronic obstructive pulmonary disease (COPD), which is a combination of non-invasive ventilation (NIV) with thermal heliox (t-He/O 2 ), nitric oxide (NO 2 ) and molecular hydrogen (H 2 ), in the Russian Federation and in the world. The aim of the study was to investigate the efficacy and safety of the combined use of t-He/O 2 , NO and H 2 in patients with exacerbation of COPD complicated by hypoxemic, hypercapnic RF and secondary pulmonary hypertension (PH) in the post-COVID period. Methods. The randomized, comparative, controlled, parallel-group, prospective study included 100 patients (52 men, 48 women) with exacerbation of COPD categories C and D according to the criteria of the Global Initiative for Chronic Obstructive Lung Disease (GOLD, 2021 – 2023), with hypoxemic, hypercapnic respiratory failure and PH, who had COVID-19 ( COronaVIrus Disease 2019) complicated by pneumonia caused by SARS-CoV-2 ( Severe Acute Respiratory Syndrome-related CoronaVirus 2) before the hospitalization. Patients with similar demographic, clinical, and functional parameters, who received, along with standard drug therapy, NIV in the spontaneous-forced biphasic positive airway pressure (BiPAP S/T) mode and oxygen (O 2 ) to maintain blood hemoglobin oxygen saturation (SpO 2 ) in the range of 95–97% according to GOLD (2021 – 2023), were divided into 5 groups: patients of the 1 st (main) group ( n = 22: 12 men, 10 women) received t-He/O 2 , NO, and H 2 sequentially; the 2 nd group ( n = 20: 10 men, 10 women) – t-He/O 2 and NO; the 3 rd group ( n = 20: 11 men, 9 women) – t-He/O 2 and H 2 ; the 4 th group ( n = 18: 10 men, 8 women) – NO and H 2 ; the 5 th group (control) ( n = 20: 9 men, 11 women) – only standard drug therapy, NIV and O 2 . Changes in the clinical condition of the patients, gas exchange in the lungs, acid-base balance, left-to-right shunt fraction, hemodynamic parameters, and exercise tolerance (ET) were assessed. Results. Not only clinical condition of the patients, but also the arterial blood gas composition, acid-base balance and intrapulmonary blood shunt fraction, hemodynamics and ET were improved in the main group compared to those in patients who received inhalation therapy with medical gases separately and the control group. Conclusion. The combination of t-He/O 2 , NO and H 2 combined with pathogenetic therapy and NIV in patients with exacerbation of COPD complicated by hypoxemic, hypercapnic DN and secondary PH in the post-COVID period is safe and more effective compared to administering each medical gas separately. The clinical condition of patients improves, signs of hypoxemia and hypercapnia, vascular endothelial dysfunction, and metabolic disorders are reduced with the combined therapy. An increase in ET was also noted due to the normalization of gas exchange in the lungs, increased oxygen delivery to tissues, a decrease in the shunt fraction, and restoration of metabolism.