IntraoperativeAutotransfusion of RBC and PRP TATM 1999;3:5-13 • Intraoperative autotransfusion In addition, IP may be used when other autologous whole blood harvesting techniques are not an option.
DEPARTMENT OF ANESTHESIOLOGY AND INTENSIVE CARE
UNIVERSITY OF GRAZ GRAZ, AUSTRIATransfusion Alternatives in Transfusion Medicine VOLUME 1 NUMBER 3 DECEMBER 1999
Background summaryIntraoperative autotransfusion (IAT) is defined as the reinfusion of patient blood salvaged during and after surgery. IAT plays an important role in the context of perioperative blood saving strategies, having gained standard-of-care status in many surgical procedures 1,6 .The principle of IAT is to collect intraor postoperatively shed blood continuously from the operative field. The salvaged blood is aspirated from the wound site and collected in a dedicated reservoir. Under standard conditions, red cells are subsequently separated, washed, concentrated and stored for later retransfusion to the patient. Only erythrocytes are saved and retransfused; simultaneous volume and plasma replacement has to be provided, especially after processing of large quantities of shed blood 4 .In contrast to stored RBCs, freshly salvaged autologous red cells show uncompromized functional capacity, oxygen delivery to tissues and survival, indicating that IAT has no significant detrimental effects on erythrocytes 7,8 . IAT is most effective when combined with other autologous methods, particularly with preoperative autologous blood donation, acute normovolemic hemodilution or adjuvant drug therapies 4, 9, 10 .
Methods
Cell separation (washed blood)This technique is based on centrifugation, separating red blood cells (RBCs) from the lighter components and fluids, including plasma, saline and the buffy coat (Cell Saver, Haemolite ® , Haemonetics TM , Braintree, MA; Figure 1). Before starting the procedure, the operator must fill the system with 100-200 mL heparinized saline ("priming"), in order to prevent cells from binding to membrane surfaces initiating microaggregation, and to diminish frictional forces and damage to the cellu-
Figure 1lar components 4,8 . Blood released at the wound site is aspirated via a double-lumen suction catheter (80-100 mm Hg), immediately anticoagulated (30,000 IU heparin in 1000 mL saline) at the suction tip, and stored in a plastic cardiotomy reservoir, equipped with a 120 µm microaggregate filter. When a minimum of 1000 mL shed blood is collected, it is pumped into a rotating separation chamber (Latham bowl, 225 mL adaptable capacity), washed with 1000-1500 mL saline and concentrated. Whenever the extent or kind of surgical debris requires more extensive washing, processing cycles can be selected manually, and in emergency cases, washing can be skipped entirely. For pediatric patients, smaller centrifuges are available. As soon as the preset hematocrit is reached, the spinning separator chamber stops, and packed RBCs, suspended in saline solution, are pumped into an infusion bag, while the waste products are removed 4, 11 . Afte...