Blood conservation in elective surgery

Abstract

AbstractThe primary aim of blood conservation is to reduce blood loss during major surgery. Some surgery however inevitably involves blood loss and in this situation blood conservation techniques are indicated. These techniques include preoperative donation, simple haemodilution, combined haemodilution and intraoperative autologous blood transfusion and blood scavenging during and after surgery.Simple haemodilutionSimple haemodilution involves the use of a suitable colloid for blood replacement during surgery until the patient's haemoglobin falls below 8–10g/dl. This technique is widely practised and can only be safe if repeated haemoglobin measurements are made throughout the operation and postoperative course.Combined intraoperative haemodilution and autotranfusionIn this process two units of blood are taken from the patient after induction of anaesthesia and are replaced with a suitable colloid. Our preference is to use polygeline because it is relatively cheap, has a low reaction rate and its short half‐life is an advantage. The two units of blood collected are retransfused at the end of surgery, thus boosting the patient's haemoglobin and supplying a significant amount of platelets and coagulation factors. Blood that is lost during surgery has a lower haemoglobin and therefore the net loss in red cells is less with the process than if the patient's haemoglobin was left at a normal level.Intraoperative scavengingThis involves the collection of blood from the operative site during surgery in a sterile fashion. The blood can then either be retransfused as whole blood or processed using a cell processor, washing the red cells and supplying washed packed red cells. These techniques have become more practical with the advent of cheaper disposable equipment and have some place in major surgery.ConclusionBlood conservation techniques involve a number of different approaches, each of which can be applied in a specific situation provided one has sufficient experience in their application.