Cell salvage and leucodepletion

Cell salvage has been used as a method of blood conservation for more than three decades. Although the principles and development of the Latham bowl had occurred in the 1960s, it was not until the early 1970s that washing of the concentrated red cells was introduced and a product that was universally acceptable was obtained. The last 25 years have seen little in the way of development of cell salvage, although significant refinement has taken place. Although the simple picture of cell salvage involves removal of the buffy coat, including platelets and leucocytes, in practice there are reports of great variation in the removal of these cells. Most recent studies suggest that there is very little removal of leucocytes by cell salvage. The leucocytes that remain in the red cell suspension following cell salvage have undergone significant morphological changes and the surface expression of leucocyte adhesion receptors increases dramatically during the process. There is little evidence that removal of these activated leucocytes has any significant clinical benefit. Although leucofiltration of blood before storage has been shown to be an extremely safe process, 'bedside leucofiltration', including leucofiltration of cell salvage blood, may not be without problems. Reports of hypotensive events while receiving blood products through a bedside leucocyte reduction filter have emerged during the last few years. This may be due to bradykinin production following platelet exposure to negatively charged leucocyte filters.