It has been shown that the new coronavirus infection is life-threatening for patients not because of the COVID-19 virus, but because of the complications it causes. The most dangerous complication of this disease is the airway obstruction syndrome, which occurs with atypical pneumonia. Blockage of the airways occurs due to the accumulation of excessively large amounts of mucus and pus in them and swelling of the lung tissue, so ventilation of the lungs with air becomes almost impossible. The sad outcome of respiratory obstruction is hypoxia and hypoxic brain damage. Under these conditions, extracorporeal membrane oxygenation remains the only known way to increase blood oxygenation. However, in 2021, it was shown that intra-pulmonary administration of a warm alkaline solution of hydrogen peroxide immediately turns mucus and pus into oxygen foam and increases blood oxygen saturation. The proposed technology is a new variant of emergency blood oxygenation in severe suffocation caused by blockage of the respiratory tract with mucus, pus and blood.

COVID-19 causes non-specific pneumonia, which has become a new cause of hypoxia, leading to the death of many patients. Today, there are no effective drugs that provide an urgent increase in blood oxygenation. Therefore, it is urgently necessary to develop drugs to increase blood oxygenation in order to save the lives of patients with the new coronavirus infection. Since hypoxia develops in this disease due to the blockage of respiratory tract with viscous mucus and sputum, an appropriate experimental model is needed for screening and finding new drugs. However this model is yet missing. Therefore, the development of an experimental model of respiratory obstruction by sputum with traces of blood can accelerate the discovery of drugs that eliminate hypoxia and prevent the death of patients with nonspecific pneumonia complicated by respiratory obstruction. The purpose of this letter was to present a model for evaluating the biological activity of drugs, which can become a new vector for the development of effective ways to increase blood oxygenation across pulmonary and save the lives of patients with severe atypical pneumonia complicated by respiratory obstruction in COVID-19.

After reading with great interest the article entitled: "Non-vitamin K antagonist oral anticoagulants (NOACs) do not increase the risk of hepatic impairment in patients with non-valvular atrial fibrillation: insights from multi-source medical data" authored by Zhi-Chun Gu et al. and published by Reviews in Cardiovascular Medicine, we would like to add the following thoughts. Oral anticoagulants are generally accepted in patients with non-valvular atrial fibrillation to prevent thrombosis and stroke. Since anticoagulants are taken daily for many months in these patients, we cannot rule out chronic poisoning and the development of liver failure. But another complication is just as likely, that being bleeding. Thus, the determining risk factor for the health of patients with a prolonged course of oral anticoagulants is hypofunctional activity of the blood coagulation system, which remains at the same level throughout the course of treatment. At the same time, it is the activity of the blood coagulation system that is an important and very sensitive link of adaptation to various external and internal factors, including anticoagulants. The fact is that regular and prolonged oral use of anticoagulants is likely to develop and tolerance to them. That is why it is necessary to carefully study the relationship between the dose of oral anticoagulants, the duration of pharmacotherapy and the development of thrombosis (bleeding) in patients with non-valvular atrial fibrillation.

Pyolytics are drugs that dissolve thick pus when applied topically. This group of drugs was discovered in early 21st century in Russia as a result of successful repurposing of antiseptics hydrogen peroxide, sodium bicarbonate and sodium chloride from antiseptics to pyolytics. Prior to this watershed event in pharmacy, the problem of effective treatment of purulent diseases had not been solved. The fact is that before that in the treatment of various purulent diseases mainly antiseptics and disinfectants solutions were used, of which hypertonic sodium chloride solution and 3 - 6% hydrogen peroxide solutions took the leading role as "antipurulent" drugs. However, the use of the known antiseptics and disinfectants solutions provided disinfection of the treated surface, but not dissolution of thick pus masses, as the solutions had no effective pyolytic action. Pyolytic activity, i.e. activity of dissolution of thick pus masses, was fantastically increased in hydrogen peroxide solutions only after the possibility of transformation of "old" drugs into "new" drugs by means of artificial changes in physical and chemical properties of their dosage forms was discovered. The greatest (explosive) effect was achieved by developing warm alkaline hydrogen peroxide solutions enriched with oxygen gas under increased pressure. In chronological order, an overview is given of Russian inventions, which formed the basis for the physicochemical repurposing of hydrogen peroxide solutions into pyolytics as well as the basis of temperature and physicochemical pharmacology and pharmaceutics.