[Observations of blood circulation disturbance in random skin flap]

Thirty-nine rats were used to study the mechanism of random flap necrosis. A random flap (3 cm x 9 cm) created on the back of each rat was observed with naked eye, microscope, skin thermometer and laser Doppler flowmeter. The average surviving length of the flap was 4.69 +/- 0.47 cm. We found that the following observations indicated circulation disturbance in the "shock flap": After surgery, the color of the flap became dark; skin temperature kept falling; when the room temperature was about 20 degrees C, the flap temperature was below 28.5-29.0 degrees C; at one hour postoperation, LDF value decreased more than 50%; microcirculation of the flap stagnated without recovery. We conclude that necrosis of the flap can be fully predicted.