The effect of replacement fluids and normovolaemic haemodilution on the survival of dorsal skin flaps in rats

The objective of this study is to investigate the effect of normovolaemic haemodilution (anaemia), haemoglobin level and replacement fluids on the survival of local flaps in rats. Fifty male Wistar rats were divided into four study groups and one control group (10 rats for each). In the study groups, 20% or 30% of blood was withdrawn and replaced by either Gelofusine or saline (0.9%). Single 1.5 cm x 3 cm cranially based dorsal random skin flaps consisting of skin and panniculus carnosus were elevated in all rats. No difference was determined between the control and 20% exsanguinated groups regarding flap survival area. There was a statistically significant difference between the flap survival areas of 20% exsanguinated groups and 30% exsanguinated groups. If the blood loss exceeds 30% of total volume and/or haemoglobin (Hb) level is lower than 10.72 g/dL, the risk of flap necrosis increases significantly.