Fat elimination during intraoperative autotransfusion: an in vitro investigation

Intraoperative autotransfusion of scavenged blood is an established method to reduce the need for perioperative homologous blood transfusion. However, if fat particles contaminate blood suctioned from the wound site, no reliable method is available to remove them during the washing and concentration of the recycled blood. A new generation of autotransfusion devices (e.g., continuous autotransfusion system [CATS]), based on separation chambers used in cell separators or plasmapheresis devices, allows continuous procession of the collected blood, in contrast with the discontinuous process used in conventional autotransfusion devices such as the Cell Saver 5. Theoretically, the continuous system should be more efficient than the discontinuous system in eliminating fat. Outdated, 36-day-old packed red blood cells, 600 mL, were mixed with 500 mL of lactated Ringer's solution and 200 mL of soya oil. Soya oil was used because it has a fatty acid composition similar to that of fat found in bone marrow. The blood mixture was then washed and concentrated by using either the CATS or the Cell Saver 5. Six samples were processed by each device. The CATS eliminated the soya oil (200 mL) completely, whereas the Cell Saver 5 delivered 30.3 +/- 7.8 mL soya oil into the retransfusion bag. The new generation of autotransfusion devices allows complete removal of fat particles.

Autotransfusion devices serve to wash and retransfuse blood scavenged from the wound site. However, they cannot completely remove fat particles. This in vitro investigation showed that a new device completely removes fat particles and thus prevents retransfusion of fat.