In the 1974 PRS article entitled, "The effect of local anaesthesia with epinephrine on skin flap survival," it was found that "infiltration with xylocaine alone had no influence on the viability of either non-delayed or delayed flaps. However, the addition of 1:200,000 epineprhine which was not detrimental to survival length in non-delayed flaps, significantly reduced the surviving length in delayed skin flaps." This study was done in pigs, an animal with a similar cutaneous blood supply.
In the 1978 PRS article, these findings were confirmed, and in addition showed that epinephrine used at both 1:200,000 and 1:400,000 significantly increases losses to the delayed flaps. However, epinephrine used at 1:100,000, 1:200,000 and 1:400,000 were not demonstrated to be harmful to undelayed flaps.