**2.1 Pre-operative autologous blood donation**

The efficacy of pre-operative blood donation varies according to the time between blood collection and cardiac surgery. The current storage and preservation techniques allow us to collect and maintain 2 to 4 units of full blood or PRBCs. This efficacy can be enhanced by stimulation of erythropoiesis during blood donation, but this is used only selectively because of the potential of thrombotic cardiovascular events and costs [11, 12]. The use of erythropoietin is also limited by the necessity of starting its administration 3 weeks before surgery [13]. A short course erythropoietin was also used several days before cardiac

Modality Intervetion

Bleeding minimization Sophisticated technology of incision

Homeostasis optimization Controlled hemostasis ( blood fluidity )

Adherence to basic rule of transfusion Complying with lowest and safe level of

The efficacy of pre-operative blood donation varies according to the time between blood collection and cardiac surgery. The current storage and preservation techniques allow us to collect and maintain 2 to 4 units of full blood or PRBCs. This efficacy can be enhanced by stimulation of erythropoiesis during blood donation, but this is used only selectively because of the potential of thrombotic cardiovascular events and costs [11, 12]. The use of erythropoietin is also limited by the necessity of starting its administration 3 weeks before surgery [13]. A short course erythropoietin was also used several days before cardiac

Table 1. Policy for limitation of blood bank transfusion in cardiac surgery

**2.1 Pre-operative autologous blood donation** 

Fe supplementation, vitamines (C,

Autologous blood donation of 1-3 units:

folates, B12), short-course

a: blood bank center collection b: perioperative isovolemic

(argon atmosphere, laser scalpel,…) Refinements of surgical methods Topical hemostatic agents Peroperative blood recuperation Postoperative blood salvage Early revision for surgical bleeding

Low priming volume and retrograde

Controlled hemodynamics ( blood

anemia for a given clinical case STS recommended transfusion point:

Internal environment (pH, blood gases,

priming after starting CPB

Ultrafiltration Minicircuits

pressure ) Normothermia

ionts, glycaemia )

Hb 7 ± 1 g/dl .

erythropoietin,

hemodiloution

Preoperative erythrocyte maximizing

Hemodilution minimization during

CPB

and/or blood conservation

operation in anemic patients (haemoglobin < 13 g/dl) without autologous predonation [14, 15]. In cardiac patients, there are certain contraindications for participation in autologous blood donation programmes; in addition to anaemia (haematocrit below 33%), they include critical aortic stenosis, idiopathic subaortal stenosis, ischaemic heart disease with unstable angina or with left main coronary artery stenosis, chronic NYHA class IV heart failure, ventricular rhythm disturbances on the day of blood collection and an acute heart attack. This all narrows the selection of candidates for autologous blood donation in cardiac surgery. The proportion of patients meeting the criteria for autotransfusion varies from 10% to 30%; however, some centres can indicate more patients in relation to the range of surgical procedures done and according to experience of the blood collection team.

#### **Intra-operative isovolaemic haemodilution**

Blood collection performed immediately before cardiac surgery for the purpose of acute isovolaemic haemodilution is also included in an autologous blood donation programme, thus permitting participation of the patients otherwise contraindicated for a standard programme [16]. A 500- to 1000-ml amount of blood is collected via a central venous catheter or an arterial line and is replaced by a colloid or crystalloid solution before cardiopulmonary bypass (CPB) surgery is commenced. For calculation of the final haematocrit (HCT) value, it is necessary to take the CPB dilutional effect (minimum of 1.3 l) into consideration. Usually, a dilution of 25% to 20 % HCT is used, which is also recommended because of a lower risk of damage to blood elements during extracorporeal perfusion. In some centres, 15% HCT is an accepted transfusion trigger in the patients who do not tolerate allogeneic blood transfusion [17, 18].

The advantage of intra-operative haemodilution is in that the lost blood contains lower red blood cell counts and a transfusion of fresh autologous blood supplies functional platelets. The only contraindication for intra-operative isovolaemic haemodilution is anaemia and haemodynamic instability. Patients with a cardiac disease and a haemoglobin level below 130 g/l may not be able to compensate for a temporary decrease in erythrocyte counts and may show signs of tissue hypoxia or symptoms of cardiac disease. This approach can be combined with blood processing by apheresis.

#### **Intra-operative apheresis**

It was first used in thoracic surgery in 1987. It is a medical technology in which the blood of a patient is passed through an apparatus that separates out plasma and platelets and returns the reminder to the circulation. The separated components are then ready for use at the time needed to complete their deficiency. During cardiac surgery with extracorporeal circulation, this technology can also salvage part of the platelets which are otherwise absorbed onto the inner surface of the extracorporeal tubing or can end as platelet-leukocytes micro-aggregates in the capillary beds. The anaesthesiologist can decide between plasma with platelets or a platelet concentrate requiring a slowly rocking shaker for short-term maintenance. Similarly to many blood recuperation devices, the apheresis technique is based on centrifugal force. The proportion of platelets in plasma depends on the spin rate (2400-3600 revolutions per min). The amount of plasma safely collected is related to the patient's clinical condition and usually equals to 20 % of the calculated plasma volume or 12 ml/kg body weight. The procedure design for replenishing intravascular volume, which differs from centre to centre, involves crystalloids and starch derivatives or albumin. When a larger amount of blood is collected, it is necessary to check the ionogram, pH value and free calcium and magnesium levels. The efficiency of both plasmapheresis and thrombopheresis has been evaluated in many studies. Some have reported lower requirements for allogeneic blood transfusion [19, 20, 21] as well as lower post-operative blood losses [22]. A positive effect of pre-operative plasmapheresis has been demonstrated by low tendency to pathological fibrinolysis [23]. On the other hand, other authors described a low efficacy of pre-operative apheresis in cardiac surgery [24] and related it to the pre-operative administration of an anticoagulation and platelet anti-aggregation therapy. The patients who, before surgery, have received coumarin derivatives, heparin and non-steroidal anti-phlogistic drugs do not benefit from plasmapheresis [25].
