**4.2 Postoperative bleeding and transfusion**

One of the most important adverse events after CABG is excessive blood loss, resulting in blood transfusion which increases mortality risk, ischemic morbidity, infections, hospital stay and overall health care costs following CABG (Augoustides et al,2009).

In order to prevent blood loss, it is important to identify the patients with increased risk of bleeding and also the patients who may develop adverse events related to transfusion. Advanced age, low preoperative red cell volume, preoperative usage of antithrombotic and antiplatelet drugs, reoperations, combined procedures, emergency surgery and comorbidities are the major contributing factors to the risk of bleeding (Augoustides et al,2009). Limiting bleeding and tranfusion after CABG begins with adequate preparation of the operating room and ICU with full institutional support. A guideline to lead a systematic, standardized approach is also an important factor for limiting bleeding and tranfusion (Ferraris&Spiess,2007).

In the preoperative period usage of anticoagulants leads to an increased risk of bleeding, thus if clinically feasible, the anticoagulants should be stopped allowing coagulation system to recover (Augoustides et al,2009). Clopidogrel, a high-intensity platelet blocker, is reasonable to be discontinued for at least 5-7 days before surgery (Ferraris&Spiess,2007). The low-intensity antiplatelet aspirin therapy is recommended to be stopped in elective patients without acute coronary syndromes (Ferraris et al,2002).

In combination with appropriate erythropoietin and iron therapy, donation of 2 units of autologous blood before CABG, significantly reduces allogenic blood transfusions. Kahraman et al. reported that acute intraoperative hemodilution reduces the blood requirements without affecting RBC volume loss and high-volume phlebotomy does not provide any additional benefit (Kahraman et al,1997). Antifibrinolytic agents can be used to limit bleeding and transfusion; tranexamic acid and aminocaproic acid are the major agents that can be used instead of aprotinin, providing a reduction in bleeding and blood transfusion; especially recommended for their usage in the high-risk subgroups (Henry et al, 2007; Umscheid et al, 2007). Desmopressin is reserved for patients who have pletelet dysfunction in the preoperative period and also factor 7a therapy has been shown to be effective in the management of refractory bleeding after CABG (Warren et al,2007).

As it exerts a mechanical pressure on the heart PEEP can be used to limit bleeding and need for transfusion.

Off-pump CABG is a resonable alternative for the prevention of blood loss, however emergent conversion to CABG with CPB increases blood loss and risk of transfusion (Jin et al,2005).

Several parts of CPB circuit have been improved for patient safety. Membrane oxygenators, centrifugal pumps, heparin-coated circuits, minimized low-prime CPB circuits are the recommended types for these parts of the circuit (Augoustides et al,2009).

cardioversion in non-surgical patients (3-4 weeks of anticoagulant therapy before cardioversion in AF more than 48 hours) for cardiac surgical patients is not clear, it is acceptable to use echocardiography especially for left atrial appendage mural thrombus, immediately placing patient on heparin and continue with oral anticoagulants for 3-4 weeks after cardioversion (Echahidi,2008). POAF is well known to increase the incidence of thromboembolism and stroke, but it is also well known that anticoagulation may result in bleeding and cardiac tamponade. Risk-benefit should be considered before anticoagulant therapy is initiated, especially for patients with advanced age, uncontrolled hypertension

One of the most important adverse events after CABG is excessive blood loss, resulting in blood transfusion which increases mortality risk, ischemic morbidity, infections, hospital

In order to prevent blood loss, it is important to identify the patients with increased risk of bleeding and also the patients who may develop adverse events related to transfusion. Advanced age, low preoperative red cell volume, preoperative usage of antithrombotic and antiplatelet drugs, reoperations, combined procedures, emergency surgery and comorbidities are the major contributing factors to the risk of bleeding (Augoustides et al,2009). Limiting bleeding and tranfusion after CABG begins with adequate preparation of the operating room and ICU with full institutional support. A guideline to lead a systematic, standardized approach is also an important factor for limiting bleeding and tranfusion

In the preoperative period usage of anticoagulants leads to an increased risk of bleeding, thus if clinically feasible, the anticoagulants should be stopped allowing coagulation system to recover (Augoustides et al,2009). Clopidogrel, a high-intensity platelet blocker, is reasonable to be discontinued for at least 5-7 days before surgery (Ferraris&Spiess,2007). The low-intensity antiplatelet aspirin therapy is recommended to be stopped in elective

In combination with appropriate erythropoietin and iron therapy, donation of 2 units of autologous blood before CABG, significantly reduces allogenic blood transfusions. Kahraman et al. reported that acute intraoperative hemodilution reduces the blood requirements without affecting RBC volume loss and high-volume phlebotomy does not provide any additional benefit (Kahraman et al,1997). Antifibrinolytic agents can be used to limit bleeding and transfusion; tranexamic acid and aminocaproic acid are the major agents that can be used instead of aprotinin, providing a reduction in bleeding and blood transfusion; especially recommended for their usage in the high-risk subgroups (Henry et al, 2007; Umscheid et al, 2007). Desmopressin is reserved for patients who have pletelet dysfunction in the preoperative period and also factor 7a therapy has been shown to be

effective in the management of refractory bleeding after CABG (Warren et al,2007).

recommended types for these parts of the circuit (Augoustides et al,2009).

As it exerts a mechanical pressure on the heart PEEP can be used to limit bleeding and need

Off-pump CABG is a resonable alternative for the prevention of blood loss, however emergent conversion to CABG with CPB increases blood loss and risk of transfusion (Jin et al,2005). Several parts of CPB circuit have been improved for patient safety. Membrane oxygenators, centrifugal pumps, heparin-coated circuits, minimized low-prime CPB circuits are the

stay and overall health care costs following CABG (Augoustides et al,2009).

patients without acute coronary syndromes (Ferraris et al,2002).

and history of bleeding.

(Ferraris&Spiess,2007).

for transfusion.

**4.2 Postoperative bleeding and transfusion** 

Leukofiltration, ultrafiltration or infusion of shed mediastinal blood are other interventions that are addressed in clinical trials (Augoustides et al,2009).

In general, in CPB, it is reasonable to maintain hemoglobin >10 gr/dl in patients who are at risk of non-cardiac end-organ ischemia; and >7 gr/dl in patients who are at risk of critical end-organ injury (Augoustides et al,2009).
