This study is aimed to determine if acute normovolemic hemodilution (ANH), an established blood conservation technique, reduces the requirement for allogeneic blood transfusion in operations with prediction of surgical bleeding over 20% of estimated blood volume (EBV)

Allogeneic blood transfusion is often done during surgery to save life- threatening conditions. Blood conservation is a method that can reduce peri-operative allogeneic blood transfusion. This study has been conducted on 34 patients underwent laparotomy surgery with bleeding more than 20% of EBV. After being informed concent, research subjects were randomized into two groups: ANH (conducted ANH) and control group (without ANH). After starting general anesthesia, the ANH group was withdrawing blood based on Gross formula. Restoration of circulated volume was instituted by infusion of colloids. In control group, the operation was started right after the induction of anesthesia. The monitoring of blood pressure, heart rate, the amount of bleeding, total fluid, urine production, hemoglobin concentration and number of allogenic transfusion were recorded.

Inclusion Criteria:

• Adult patients scheduled for laparotomy under general anesthesia with potentially surgical bleeding > 20% of EBV
• ASA physical status I - II
• hemoglobin level before surgery > 11 g / dl for men and > 10 g / dl for women

Exclusion Criteria:

• impaired coagulation (INR> 1.5 and / or platelet count <100,000)
• active infection
• disruption of metabolic liver
• received anti fibrinolytic drugs