Introduction

The goal of blood conservation in cardiac surgery is to reduce or avoid patient exposure to allogeneic transfusion. In transfusion situations where the donor and recipient are the same individual, the term ‘autologous’ is used.

Blood conservation techniques

Techniques for conservation of blood, minimizing the requirement for transfusion, can be subdivided into preoperative, intraoperative and postoperative strategies, and are usually used in combination.

Preoperative phase

Elective surgery allows planning and prevention of common problems that increase the likelihood of a perioperative transfusion.

ANAEMIA

A patient who is anaemic (≤ 12.5 g/dL) is more likely to be transfused. Any patient referred for elective cardiac surgery should therefore have a full blood count checked in time to detect and treat anaemia. For example, a 4-week course of oral iron supplementation often elevates red cell mass significantly. Other deficiencies, such as folate or vitamin B12, may also be identified and corrected.

CONGENITAL COAGULOPATHIES

Patients presenting for cardiac surgery with inherited coagulation disorders, such as haemophilia, require appropriate perioperative factor replacement. Involvement of a haematologist at an early stage is advisable.

AUTOLOGOUS BLOOD PREDONATION AND ERYTHROPOIETIN

Erythropoietin (EPO) may be used to increase red cell mass alone, or to facilitate autologous blood predonation. Autologous blood predonation involves the patients donating their own blood over a number of weeks with the purpose of retransfusion at the time of surgery. Autologous blood pre-donation rose in popularity as a technique in the 1980s during the initial phase of the HIV crisis, but is now rarely practiced.