RESUMO
BACKGROUND: Acute normovolemic hemodilution (ANH) is known as the easieat and most economical and the quality of autologous blood saved by it is the best of all methods of autotransfusion. To investigate the efficacy of ANH, we studied whether it could reduce the transfusion requirement in spinal surgery. METHODS: Forty patients were randomly divided into 2 groups. In the hemodilution group (n=20), 2 or 3 units of autologous blood were procured immediately before or after anesthetic induction while Ringer's lactate and pentastarch were infused to maintain normovolemia. All patients received deliberate hypotension induced by labetalol. Perioperative changes of hemoglobin, hematocrit and platelets, the transfusion requirement and the amount of postoperative drainage were compared between each group. RESULTS: Perioperative changes of hemoglobin, hematocrit and platelet showed no significant differences between each group. Less packed RBC were used in the hemodilution group (1.9 2.0 units) than in control group (5.9 6.8 units) (p<0.05). In the control group, 4 patients were transfused with fresh frozen plasma (mean 4.8 units), 3 patients with platelets (mean 13 units) and 1 patient with cryoprecipitate (10 units) while only one patient was transfused with 3 units of fresh frozen plasma in the hemodilution group. Postoperative drainage was significantly less in the hemodilution group (1,494 488 ml) than in the control group (2,476 1,730 ml). CONCLUSION: ANH seems to decrease the transfusion requirement in spinal surgery. Reduction of postoperative wound drainage appears to play an important role in that.