Unwashed blood: is widespread use justified? A review of current knowledge: SAFE USE OF UNWASHED BLOOD

SUMMARY Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are associated with a considerable amount of total blood loss. This results in a significant postoperative decline in hemoglobin levels, and thereby the use of allogeneic blood transfusion (ABT), which is not a risk-free therapy. Postoperative shed blood (PSB) salvage and retransfusion, after washing or filtering, was introduced as a unique blood saving concept to decrease perioperative blood loss, to maintain higher postoperative hemoglobin levels and to decrease the use of ABT. PSB reinfusion must be restricted to elective procedures with an anticipated postoperative blood loss between 750 mL and 1500 mL, allowing for the recovery of at least the equivalent of one unit of packed red cells, and used in conjunction with a defined ABT protocol. The results of a number of clinical and laboratory studies strongly suggest that reinfusion of unwashed PSB can reduce the requirements for ABT, and that most of the potential adverse effects of unwashed PSB are no more than theoretical. Therefore, reinfusion of unwashed PSB after THA and TKA is easy-to-use, safe, economic and clinically beneficial, as it may reduce ABT-associated risks. The superiority of washed PSB over unwashed PSB in these procedures has not been demonstrated. All these make widespread use of unwashed PSB available for all patients and justified.