A greater effort to avoid adverse events due to transfusion has also increased the emphasis on blood conservation (see bloodless surgery).
[1] Transfusion-associated immunomodulation, which may suppress the immune response and cause adverse effects such as a small increase in the risk of postoperative infection.
Screening for transmissible diseases and deferral policies for classic CJD and vCJD designed to improve safety have unfortunately contributed to shrinking the donor pool.
[citation needed] Ways to avoid the adverse events associated with allogenic transfusion are often grouped under the umbrella phrase bloodless surgery.
RBC washing devices can help remove byproducts in salvaged blood such as activated cytokines, anaphylatoxins, and other waste substances that may have been collected in the reservoir suctioned from the surgical field.
Following bypass surgery, the ECC circuit contains a significant volume of diluted whole blood that can be harvested in transfer bags and re-infused into patients.
The filter process removes unwanted excess non-cellular plasma water, low molecular weight solutes, platelet inhibitors and some particulate matter through hemoconcentration, including activated cytokines, anaphylatoxins, and other waste substances making concentrated whole blood available for reinfusion.
However, the contaminants that are potentially reduced by using RBC-savers, as shown by data from in vitro laboratory tests, are transient and reversible in vivo with hemostatic profiles returning to baselines within hours.
Over the years numerous studies have been done to compare these methods of blood salvage in terms of safety, patient outcomes, and cost effectiveness, often with equivocal or contradictory results.