Effects of Normovolemic Hemodilution on Survival of Skin Flaps: An Experimental Study

BACKGROUND The aim of this study was to investigate the effects of various ratios of hemodilution on the survival of McFarlane's skin flaps. MATERIAL AND METHODS An experimental study was performed on 42 adult male Wistar rats (weighing 260 to 305 g) allocated to a control group without any volume loss and to 6 study groups with hemodilution ratios of 5%, 10%, 15%, 20%, 25%, and 30%. In all subjects, random-pattern McFarlane's skin flaps were uniformly elevated and re-sutured to the donor sites. The amount of necrosis was evaluated on the 7th day postoperatively and compared among the groups. RESULTS The amounts of flap necrosis in the groups with 5%, 10%, 15%, and 20% hemodilution ratios were significantly lower than that of the control group (p<0.001). In the 25% and 30% hemodilution groups, although there was less necrosis than in the control group, the differences were not statistically significant. Hematocrit levels, which initially decreased in conjunction with the hemodilution ratios, returned to normal levels on the 7th day after the operation. CONCLUSIONS Our results indicated that 20% or less of the total blood volume loss that may be compensated by the normovolemic hemodilution with dextran can improve flap survival.