Fluorometric analysis of an attempt to reclaim ischemic flaps in rats with Fluosol

An experiment was designed to answer two questions as they apply to random skin-flap survival: Is there a therapy that can improve random skin-flap survival when given postoperatively? And if so, when does one start such a therapy? Fluosol-DA 20% (Fluosol) has increased random skin-flap survival when given preoperatively in our laboratory. An experiment was devised to see if it could rescue failing flaps. One-hundred Sprague-Dawley rats were divided into a control (N = 25) and five experimental groups (N = 15). All had 10 X 13 cm reverse McFarlane random flaps raised and reinset. The experimental groups underwent hemodilution with either Ringer's lactate or Fluosol at 4, 8, and 12 hours after flap elevation. All were kept in 50% oxygen for 72 hours postoperatively. The flaps and their corresponding necrotic areas were measured on day 7. As to when to institute a therapy, we simultaneously evaluated the use of a microfluorometer as a monitor of flap survival. Analysis of flap survival showed little difference between control and experimental Ringer's lactate or Fluosol groups. Analysis of the microfluorometric data led to the following points. First, as a monitor of flap viability, it is limited by a lack of specificity and sensitivity. Second, comparison of the data from portions of the flap destined to live with those destined to die suggests that it may not be failure of circulatory inflow that leads to flap death.