Haemodynamics of the delayed skin flap: a total blood-flow study.

Pedicle skin flaps in dogs were delayed and venous outflow measured at various times following a delay procedure. An initial small but significant decrease in blood flow was noted in the first 48 hours postoperatively in several flaps suggesting that a denervation supersensitivity-arteriovenous shunt mechanism may be active at this time. In all flaps after the second day, total flap blood flow markedly increased compared to the initial measurement. This suggests that the most significant haemodynamic event occurring during the delay period is the development of vascular collaterals.