Reviews
Katharina Schulte, Rizwan Atti
Abstract
surgery poses a higher risk for bleeding diathesis. Predictors of bleeding include patient factors such as older age, emergency surgery, lower body surface area and the use of perioperative antiplatelet agents. Operative factors include prolonged cardiopulmonary bypass (CPB) time, complexity of surgery, reoperative surgery and prolonged hypothermia. Between 2% and 15% of patients require re-exploration for bleeding. Although a surgically correctable source is found in 50% to 67% of cases, bleeding and surgical re-exploration are independent predictors of adverse outcome. The use of allogeneic transfusions is associated with numerous adverse outcomes such as an increase in nosocomial infection and mortality in critically ill patients. Blood conservation strategies and steps to minimize bleeding are the desired clinical goal. Preoperative antiplatelet agents are limited when possible. Transfusion triggers use hemoglobin levels and platelet counts to guide treatment. Advanced measurements (whole body oxygen-carrying capacity, oxygen consumption, oxygen extraction ratios and oxygen delivery) represent accurate methods to estimate the need for transfusion. Intraoperative deployment of minimally invasive techniques and meticulous hemostasis reduce blood loss. Modified strategies for CPB are discussed such as using activated clotting time-guided heparinization, retrograde autologous priming of the CPB circuit, autotransfusion and cell salvage. Postoperative use of autologous transfusion strategies, and pharmacological adjuncts, such as aprotinin, lysine analogues epsilon-aminocaproic acid and tranexamic acid, are discussed. Specific correction of coagulation using fresh frozen plasma, cryoprecipitate or factor VIIa may be required. The multimodality approach to blood loss aims to optimize outcomes in highrisk aortic surgical patients.