Emergency medicine and resuscitation
Ian Greaves in Military Medicine in Iraq and Afghanistan, 2018
In terms of optimal ratios of blood to other blood products, several retrospective studies have now been overtaken by a large prospective trial – the PROPPR study, which randomised civilian trauma patients to receive either 1:1:1 (plasma, platelets and pRBCs) or 1:1:2.18 Although no overall mortality benefit was found, there were significant differences in early deaths due to bleeding in favour of the higher ratio, supporting as close to 1:1:1 ratios as possible as the initial target. However, all trauma patients are different, and near-patient functional coagulation testing is now employed in the deployed (Role 3) setting, which allows bespoke blood product transfusion depending on the patient’s specific requirements.19 Rotational thromboelastometry (ROTEM™) or thromboelastography (TEG) both allow measurement of clot initiation and function as well as more traditional coagulation parameters. Despite the observed benefit in practice, a recent Cochrane review has suggested that there is not yet enough evidence to support its routine use in guiding trauma resuscitation.20
Pelvic fractures
Charles M Court-Brown, Margaret M McQueen, Marc F Swiontkowski, David Ring, Susan M Friedman, Andrew D Duckworth in Musculoskeletal Trauma in the Elderly, 2016
Monitoring of coagulation in bleeding patients has also changed. It was recognized that traditional laboratory tests including prothrombin time and partial thromboplastin time only test selected components of the coagulation process.68 They also have the salient disadvantage that they are time consuming and therefore not available at the point of care when the patient is still haemodynamically unstable. The old cascade model of coagulation has now been replaced with a newer cell based model which emphasizes the role of cellular elements, particularly platelets, in haemostasis. This cell based model is in three phases: initiation, amplification and propagation, and the quality of haemostasis is dependent on the quantity of thrombin production. Tests have been developed to reflect this newer concept of haemostasis and include viscoelastic haemostatic assays of thromboelastography and rotational thromboelastometry.69 These tests have a number of advantages over older investigations: they can be performed much more quickly so results are available during the resuscitation phase. They can also reveal low fibrinogen, poor platelet function and hyperfibrinolysis and so are a much better guide to blood product requirement and type of product needed.
Antepartum Haemorrhage
Sanjeewa Padumadasa, Malik Goonewardene in Obstetric Emergencies, 2021
Continuous dialogue between the operator/s, the anaesthesiologist and the nursing staff, as well as attention to blood loss, haemoglobin, electrolytes and coagulation parameters are pivotal in ensuring the safety of the woman. Transfusion of blood and blood products can be guided by rotational thromboelastometry, if this is available. The use of an autologous cell saver is also an option, and this reduces the need for allogenic blood transfusion without any adverse sequelae. The antifibrinolytic agent, tranexamic acid 1 g IV should be administered early, but its function as a prophylactic agent against haemorrhage in PAS disorders has not been proven. It is imperative to keep the patient warm, because many clotting factors work poorly in the presence of hypothermia. Manual aortic compression (just above the bifurcation of the aorta, with compression released every 30 minutes) can be utilised to control haemorrhage until hysterectomy is completed (discussed in Chapter 14).
Does plateletpheresis induce a hypercoagulable state? A global assessment of donor’s hemostatic system by ROTEM
Published in Platelets, 2019
O. Meltem Akay, Fatih Taştekin, Ertuğrul Çolak
In the last decade, thromboelastometry has became a valuable tool of coagulation testing for the diagnosis and management of hemostatic disorders. Thromboelastometry is a technique that provides data about the entire coagulation system, from the beginning of clot formation to fibrinolysis, involving both cellular and plasma components of hemostasis. Rotational thromboelastometry (ROTEM) which evolved from thromboelastometry technology avoids several limitations of classical method while maintaining a good correlation with conventional thromboelastometry determination. The most important benefits of ROTEM technology include the rapid availability of test results, less susceptibility to mechanical stress, movement and vibration; as well as providing enhanced reproducibility [11]. The data is also continuous, digital, and retrievable for further calculations [12].
Rotational thromboelastometry (ROTEM) profiling of COVID–19 patients
Published in Platelets, 2021
Mirjana Mitrovic, Nikica Sabljic, Zorica Cvetkovic, Nikola Pantic, Aleksandra Zivkovic Dakic, Zoran Bukumiric, Vesna Libek, Nebojsa Savic, Branislava Milenkovic, Marijana Virijevic, Violeta Vucinic, Ivana Milosevic, Zlatko Pravdic, Nada Suvajdzic, Jawed Fareed, Darko Antic
Conventional coagulation and fibrinolytic tests reflect only limited parts of the coagulation system and are insufficient for assessment of hypercoagulation[10]. Viscoelastic tests (VETs), such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM), as a whole blood analysis has the advantage of providing information related to clot formation, clot elasticity development, and the fibrinolysis process in real time[10]. Depending on the substrate added into the cuvette along with phospholipids and calcium, several ROTEM tests can be assessed. Extrinsic rotational thromboelastometry (EXTEM) is initiated by adding a tissue factor and imitates the extrinsic pathway. Fibrinogen rotational thromboelastometry (FIBTEM) is initiated like EXTEM but by adding of cytochalasin D, platelet cytoskeleton is inhibited, so the whole clot formation depends on fibrinogen[10]. Moreover, recent literature has stated that in critically ill patients with sepsis, ROTEM is useful in identifying a hypercoagulable state [11,12],
Platelet function assessed by ROTEM® platelet in patients receiving antiplatelet therapy during cardiac and vascular surgery
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2022
Anna Schultz-Lebahn, Peter H. Nissen, Troels Fogh Pedersen, Mariann Tang, Anne-Mette Hvas
In patients bleeding during or after surgery, the cause must rapidly be determined to support targeted hemostatic treatment. Rotational thromboelastometry (ROTEM®) is used for diagnosing and monitoring of bleeding patients, but this method does not systematically reveal the effect of antiplatelet therapy [36]. The gold standard platelet function test is light transmission aggregometry (LTA) [37], but the method holds some disadvantages, among other the pre-analytical preparation of platelet-rich plasma (PRP) which is a time-consuming step. A recent diagnostic modality for platelet function testing, ROTEM®platelet, employs whole blood impedance aggregometry. It has been marketed as capable of detecting reduced platelet function due to antiplatelet therapy.