Patients undergoing surgery are at risk of haemorrhagic complications. In these cases, immediate blood transfusions are often required. However, according to current guidelines, increasing evidence supports use of PBM, a patient-centred, systemic and evidence-based approach to managing a patient’s own blood. Under these guidelines, autologous blood transfusion may be more effective than transfusion of allogeneic blood from a donor.1
One method of autotransfusion is the use of a cell saver machine (otherwise known as the intraoperative cell savage machine or autologous blood salvage system), commonly called the “cell saver”, to suction, wash and filter blood for parenteral administration. Cell salvage is an important tool in PBM, and is widely used in orthopaedic-, trauma-, cardiac-, vascular and transplant surgery,2 in cases of severe bleeding where cell salvage adds significant value for blood supply.
Cardiac surgical procedures carry a high risk of blood-loss, and account for approximately 10% of all blood supplied by the National Blood Service in the United Kingdom.3 At least three out of four patients require the use of at least one unit of homologous transfusion during cardiac surgery.4 Use of cell salvage can significantly reduce the requirement for allogeneic blood intra- and postoperatively in cardiac surgery. The administration of allogeneic blood comes with numerous risks including an increased risk of perioperative myocardial infarction.1
Conventional cardiopulmonary bypass (CPB) induces a systemic inflammatory response that can result in microembolisms to the brain and other organs. The majority of cardiac surgeons employ cardiotomy suction to preserve autologous blood during on-pump coronary artery bypass surgery.5 However, the use of cardiotomy suction is associated with a pronounced systemic response, and intraoperative autologous red cell salvage during cardiopulmonary bypass may be an attractive alternative to cardiotomy suction.5 It allows the conservation of red blood cells whilst reducing the re-transfusion of fat micro-emboli, activated coagulation and inflammatory markers. A recent study showed that coagulation function after CPB did not differ significantly when assessed either by thromboelastography or conventional laboratory tests between patients with or without intraoperative blood salvage.6
Cell salvage use should be carefully monitored during cardiac surgery, as very large volumes of blood processed through a cell saver may deplete the blood of valuable platelets and clotting factors, and additional replacement of these may be necessary.5
Whilst the use of cell salvage devices in immediate trauma care is often impractical, postoperative anaemia is a common problem in surgical intensive care units.1 Since the re-transfusion of unwashed shed blood should be avoided due to multiple side effects and low blood quality, cell salvage can be used to reduce postoperative anaemia by providing autologous blood of high quality.1 Several studies have shown that the use and administration of autologous (washed) blood collected and processed by cell salvage devices can reduce longer-term hospital stay and mortality,7,8 however, additional studies on the use of cell salvage in emergency settings are needed.
Obstetric haemorrhage currently accounts for a significant amount of allogeneic blood transfusions (up to 3% or 4% in some geographies).9 Cell salvage can be used as an option to recover shed blood for patients undergoing a caesarean section, reducing the need for an allogeneic blood transfusion and the associated risks of infectious and non-infectious complications.10 Cell salvage use for obstetric haemorrhage has been endorsed by several medical societies and has been incorporated into national guidelines including the National Institute for Health and Clinical Excellence (NICE), Italian Society of Transfusion Medicine and Immunohaematology (SIMTI) and the American Association of Blood Banks (AABB). However, a recent meta-analysis including RCTs showed no effect of cell salvage on minimising perioperative allogeneic blood transfusion in obstetric patients.11
However, the adoption of cell salvage in obstetrics has been hindered due to concerns around the theoretical risk of amniotic fluid embolism (AFE).12 The exact mechanism of the AFE reaction is currently not completely understood, but there are a growing number of reports in which foetal material has been found in the maternal circulation of women who do not have AFE.12 The washing stage of cell salvage, in combination with the use of a leucodepletion filter, significantly reduces the levels of amniotic fluid contaminants,10 and as yet, no serious complications have been directly attributed to the use of cell salvage in obstetrics.
Orthopaedic hip and spine surgeries can be associated with haemorrhage and blood loss; however, it is often difficult to predict which cases may bleed and require autologous transfusion. Cell salvage has been shown to be useful for reducing the volumes of perioperative and postoperative allogeneic RBC transfusion in scoliosis surgery, and successfully increases haemoglobin and haematocrit levels on the first day postoperatively. Some studies have also demonstrated reductions in allogeneic blood requirements when cell salvage is used in major spinal deformity surgery hip and knee arthroplasty.13 However, there are currently only low level or inconclusive evidence of benefits of cell salvage in knee and hip surgery.11,14
Cell salvage was cost-effective in complex surgeries with expected blood loss of greater than 500 mL. The American Red Cross, AABB and ABC all are projecting significant sustained blood and platelet shortages and asking hospitals to reduce blood transfusions by 10%.
