Loãng máu cấp tính Normovolemic (ANH) Kỹ thuật này liên quan đến việc WB thu thập từ các bệnh nhân ngay lập tức trước khi một thủ tục trong đó mất máu là dự đoán. Nhanh chóng thay thế lượng máu lấy ra bằng tinh thể hoặc keo giải pháp được thực hiện trước khi phẫu thuật. | 3. Blood Components 31 Acute Normovolemic Hemodilution ANH This technique involves WB collection from patients immediately prior to a procedure in which blood loss is anticipated. Rapid replacement of the removed blood volume with crystalloid or colloid solution is done prior to surgery. Re-infusion of the collected blood typically occurs toward the end of the procedure or as soon as major bleeding has stopped Goodnough et al. 1992 . The reduction of RBC loss during surgery is the purpose of this technique and is sometimes preferred to the cell saver WB collection which ends up with lower hematocrits than ANH blood products. Postoperative Blood Collection This procedure involves recovery of blood from surgical drains and is usually filtered but not always washed before reinfusion. The salvaged product may be hemolyzed and dilute. The product must be transfused within 6 hours or it must be discarded. The primary indications for postoperative blood collection are cardiac and orthopedic surgery cases. PLATELETS Description Two types of platelet components are available to most hospitals in the United States pooled platelet concentrates also called random donor platelets and apheresis platelets also called single-donor platelets . Platelet concentrates are derived from WB donations from a single donor. Apheresis platelets are collected via an apheresis device returning the other WB components to the patient. In addition to the difference in product production the amount of platelets unit is also quite distinct. It takes 5 to 8 pooled platelet concentrates 7 X 1010platelets concentrate to achieve the same dose of platelets as a single apheresis platelet unit 3 to 6 X 1011 platelets . As a result the recipient of pooled platelet concentrates is exposed to 5 to 8 times more blood donors per transfusion than a single apheresis platelet recipient. Additionally a platelet concentrate unit must undergo leukofiltration to be rendered leukoreduced WBC 5 X 106 while an apheresis
