HHE Sponsored supplement: Managing perioperative bleed | Page 12

perioperative bleeding. 5 Other studies have yielded similar findings for patients undergoing cardiac surgery. 6 Considering the potentially devastating outcomes of perioperative bleeding, the European Task Force for Advanced Bleeding Care in Trauma and the European Society of Anaesthesiology recommend immediate intervention for patients presenting haemorrhagic shock, and continual evaluation of the coagulation status before, during, and after surgery. 2,4 Conventional tests measuring coagulation parameters such as the international normalised ratio (INR), activated partial thromboplastin time (aPTT) and platelet counts are of very limited value for detecting and predicting the risk of bleeding before surgery or other invasive procedure. Oftentimes, the results are not specific (for example, INR and aPTT assess the initiation phase of coagulation, making it possible to have a false normal result, whereas platelet counts can only detect platelet dysfunction that is not induced by drugs and not acquired) or detailed enough, and they can come too late to initiate effective haemostatic control in a timely manner. 7 The implementation of point-of-care (POC) devices for coagulation analyses may help identify the often multifactorial causes of bleeding at all phases of perioperative care with only a small volume of whole blood, allowing for the screening of coagulopathies onsite, in the operating room or the intensive care unit. Two types of POC devices are currently available: viscoelastic, for the diagnosis of plasmatic disturbances of haemostasis and fibrinolysis as well as low platelet counts; and aggregometric, for the identification of platelet dysfunction, either caused by COX-1 inhibitors (for example, aspirin) or adenosine diphosphate receptor antagonists, or acquired platelet dysfunctions. Their main disadvantage is the impossibility of identifying coagulopathy caused by hypothermia/hyperthermia or anomalies in pH, calcium ion concentration or haematocrit that affect haemostasis. 7 Viscoelastic methods are based on thromboelastography and measure the time until the start of clotting, the dynamics of clotting, and the stability of blood clots over time. These techniques offer advantages relative to standard laboratory coagulation tests, namely rapid detection of coagulation anomalies resulting from the use of antithrombin agents and prediction of a need for massive blood transfusion, occurrence of thromboembolic events, and mortality in surgical and trauma patients. 2,7 By contrast, the incorporation of platelet function assessment via aggregrometry in blood management resulted in the reduction in the number of patients requiring massive transfusions or transfusions of red blood cells compared with conventional laboratory analyses, thus leading to fewer transfusion-related complications and reduced costs. 8 Initial management of perioperative bleeding and treatment escalation The first measures to limit further loss of blood include damage control surgery, coiling, and packing strategies as well as timely correction of acidosis and hypothermia, hypocalcaemia, and anaemia. In severely injured patients, 12 HHE 2018 | hospitalhealthcare.com