TRANSFUSION AND INFUSION THERAPY FOR MASSIVE BLOOD LOSS. PART 1, UNEXPECTED INTRAOPERATIVE HAEMORRHAGE
Authors: PYLYPENKO M.M , DUBROV S.O. 
Published: October 2023

Massive intraoperative bleeding has been one of the leading causes of mortality and morbidity in the perioperative period for many decades, and about a third of deaths occurred due to unexpected bleeding. Despite the widespread use of the terms massive haemorrhage (MH) and massive blood loss, their definition is still not fully agreed upon. The most widespread is the retrospective definition of MH, which is based on the number of units of blood transfused to the patient. The main manifestations of MH are the symptoms of severe haemorrhagic shock, that is, progressive overstrain of the sympathoadrenal system of the body, followed by a progressive decrease in blood pressure (BP) and cardiac output. In addition to massive haemorrhage, there are also such definition as severe bleeding, in which blood loss is about 20% of the volume of circulating blood. Severe bleeding can lead to the development of haemorrhagic shock in a particular category of patients.
In cases where MH are planned (or at least severe bleeding), surgeons prepare to stop bleeding, and anaesthesiologists prepare to compensate of blood loss according to modern principles of hemostatic resuscitation. Over the past decade, in developed countries, scientists have developed and practitioners have widely implemented the principles of Patient Blood Management into clinical practice, which primarily consist of the preoperative diagnosis of anaemia and coagulation disorders and their compensation. Controlled (permissive) arterial hypotension is performed during surgery to reduce the planned MH. When MH occurs unexpectedly, surgeons are often not ready to quickly and effectively stop it, and anaesthesiologists have neither a sufficient supply of blood components and products nor a sufficient number of human resources to carry out balanced haemotransfusions in a fast and safe way. In such cases, it is very difficult for an anesthesiologist to perform full-fledged hemostatic resuscitation, so it is important to at least partially apply its basic principles. To do this, it is necessary to determine the rate of blood loss as early as possible, as well as to identify the main physiological disorders in the body, which will make it possible to establish diagnoses of hemorrhagic shock and MH. Timely establishment of the diagnosis of MH enables the practitioners to activate the massive transfusion protocol and receive a predetermined transfusion package from the blood bank. This package typically includes several packs of blood components, including red blood cells, plasma, platelets, and blood products such as cryoprecipitate, fibrinogen, and concentrates of other clotting factors. The system for ordering transfusion packages works only under the conditions when the massive transfusion protocols are created, agreed upon, approved and implemented in the clinical practice of the blood transfusion department of the medical institution in advance. It should be emphasized that the blood supply system in different medical facilities can vary to a certain extent. Some institutions have a full-fledged blood service that can provide the operating room with a wide range of blood components and preparations, and the massive transfusion protocol in such hospitals can rely on the traditional use of group-specific blood products in a balanced ratio of 1:1:1. In other hospitals, there is a separate person responsible for the delivery of components and blood products from blood banks, storage of blood and replenishment of used stocks or those components that have expired. Such hospitals may have a small supply of red blood cells and plasma of each blood group, and a slightly larger supply of universal components - erythrocyte mass of group O(I) and plasma of group AB(IV), but platelet mass is almost never available in such institutions. Some medical centres lack both a blood service and the possibility of creating a stock of drugs or blood components of all groups, except for a small stock of universal components.
In some cases, when MK occurs and in the absence of the appropriate amount of drugs and blood components, a transfusion of warm whole blood may be performed as part of measures to save the patient's life. An additional method that helps to reduce the volume of haemotransfusion in case of haemorrhages in the thorax, and sometimes in the abdomen, is the collection and transfusion of blood that has just spilled into these clean cavities.
The approach to conducting blood transfusions, in particular the selection of blood components and products, may differ in different types of hospitals, and these differences should be fixed in the local guidelines and protocols that regulate blood transfusions. This publication emphasizes the importance of developing and approving specific clinical protocols or patient pathways that can be fully implemented in each ED. In addition, the evidence base, regulatory and legal aspects in Ukraine are presented. In the following publications, it is planned to continue the coverage of blood transfusions in the conditions of providing assistance to the injured and injured, as well as other modern aspects of infusion and transfusion therapy.