The human body, like any other, is an intermediate component of the nitrogen cycle in nature. Consuming nitrogen from the external environment in the form of various compounds, the body processes it into ammonia - one of the final products of exchange of nitrogen-containing substances [1], which is removed from the body in the form of urea. The most active ammonia producers are organs with high exchange of amino acids and biogenic amines - nerve tissue, liver, intestine, and muscles. In a state of nitrogen equilibrium, the adult body consumes and releases about 15 g of nitrogen per day, temporary or permanent disruption of nitrogen balance results in a great number of physiological conditions and diseases, and the need to stabilize it is well known. However, despite a huge number of studies on the role of nitrogen metabolism and its compounds in the clinic, to date we have not been able to find any conciliation document in the world literature on the classification of ammonia-ammonium levels in human blood and approaches to the correction of hyperammonemia, which was the basis for the emergence of this consensus.

A comprehensive interdisciplinary study is performed for 12 polymers promising for the fabrication of membranes for extracorporeal membrane oxygenation based on them by methods of gas permeability, wetting, piezoelectric microweighing, and direct biomedical methods for determining hemocompatibility of whole blood from healthy donors. It is found that trimethylsilyl-substituted polytricyclononene, polyhexafluoropropylene, and semicrystalline polyphenylene oxide are the best polymer materials for the diffusion membranes of oxygenators. It is shown that traditional approaches that associate the surface properties of polymers (water wettability, plasma protein adsorption, energy characteristics of surfaces) with their hemocompatibility do not provide precise correlations with the biomedical methods based on the analysis of the changes in the shape of blood cells as a result of adhesion on the surface of the polymer. The complexity of the mechanism of interaction of the surface of polymers with blood also does not allow for clear structureproperty correlations traditional for membrane gas separation. The directions of further research in this area are defined.

The presence or development of liver disorders can significantly complicate the course of critical illness and terminal conditions. Systemic hemostatic disorders are common in Intensive Care Units patients with cholestatic liver diseases, so the study of the mechanisms of their development can contribute to the understanding of the development of multiorgan failure in critical illness.The review discusses current data on changes in hemostatic parameters in patients with cholestatic liver diseases, proposes a mechanism for the development of such disorders, which involve interactions of phospholipids with platelet and endotheliocyte membranes. It is suggested that a trend for thrombosis in patients with cholestatic liver disease is due to increased accumulation of bile acids in the systemic circulation. Available data demonstrate that the antiphospholipid syndrome may predispose to the formation of blood clots due to alterations of phospholipid composition of membranes of platelets and vascular endothelial cells by circulating antiphospholipid antibodies. Clarifying the mechanisms contributing to changes of the blood coagulation system parameters in liver disorders will aid to development of optimal correction of hemostatic disorders in patients with chronic liver diseases.

Background. Cryoprecipitate is made from fresh-frozen plasma (FFP) and contains fibrinogen, factor VIII, factor XIII, von Willebrand factor, fibronectin and fibrinogen.Aim. To provide information on the composition and methods of production, storage, transportation and clinical use of cryoprecipitate.General findings. Cyoprecipitate is manufactured by slowly thawing FFP at 1–6°C. This precipitates out cryoproteins: factor VIII, von Willebrand factor, factor XIII, fibronectin and fibrinogen. After centrifugation, the cryoproteins are resuspended in a reduced volume of plasma. Cryoprecipitate is stored at temperatures not exceeding –25° С for 36 months. Indications for cryoprecipitate transfusion are hemophilia A, von Willebrand disease, factor XIII deficiency, congenital afibrinogenemia and hypofibrinogenemia, acquired hypofibrinogenemia. These indications can occur in obstetrics, neonatology, cardiac surgery, neurosurgery, hematology, orthopaedics, and general surgery during liver transplantation and disseminated intravascular coagulation.

Justification Given the large number of reports on the peculiarities of liver lesions during the Sars-Cov-2 infection [1], a team of experts who participated in the 23rd Congress of the Scientific Society of Gastroenterologists of Russia and 15 National Congress of Therapists of November 19, 2020 decided to make additions to the Russian Consensus of “Hyperammonemia in Adults” published early 2020 [2, 3].