Laser Doppler velocimetry and fluorescein dye in the prediction of skin flap viability. A comparison.

Laser Doppler velocimetry provides a quantitative and noninvasive measurement of cutaneous blood flow. Piglets were used to compare laser Doppler velocimetry and fluorescein with each other and as predictors of flap viability. Twenty-five random pattern rectangular skin flaps were studied with both techniques. Eighteen of the flaps were observed for two weeks and the length of viable flap documented. A reading of 100 mV on the laser Doppler corresponded with full fluorescence after dye injection. Both fluorescein and the laser Doppler underestimated flap surviving length slightly. Laser Doppler readings taken 24 hours postoperatively predicted the length of surviving flap exactly. The laser Doppler correlated well with fluorescein dye.