The Relationship of Hematocrit Levels to Skin Flap Survival Length in the Pig

The work of several investigators suggests that anemia may increase the survival length of skin flaps in the dog and the rabbit. The following experiment was designed to study the survival of standardized skin flaps of varying lengths in normocythemic, polycythemic, and anemic pigs. The pig was chosen because of the similarity of its skin to that of human skin.

Twenty-nine standardized random-pattern flaps and six standardized arterial flaps were studied in pigs with varying hematocrits. A statistically significant increase was found in the survival lengths of skin flaps in the polycythemic animal as compared with the anemic one. No significant difference was found when the flap survival lengths of the normocythemic control animal were compared with those of the polycythemic animal or with those of the anemic animal. These findings suggest that relative polycythemia may allow improved flap length-survival and, in contradistinction to the findings of previous investigators, that anemia does not result in improved survival length.