Menu		Inservice Exam 2005 Microsurgery Clinically proven effects of dextran include which of the following? (A) Improved flap survival (B) Increased systemic complications (C) Ischemia reperfusion protection (D) Leukopenia The correct response is Option B. Low-molecular-weight dextran is a polysaccharide produced by bacteria that is frequently used as an antithrombotic agent in microsurgical procedures. It is believed to have multiple actions, including decreasing platelet aggregation, increasing fibrin degradation, inhibiting alpha-2 plasmin, decreasing factor VII and von Willebrand factor and thereby altering platelet function, as well as acting as a volume expander. Anaphylactic reactions to this substance can occur, and many practitioners recommend administering a test dose of the hapten dextran one hour before starting infusion. However, severe reactions are uncommon and generally are noted early in its administration. Cases of pulmonary edema and acute respiratory distress syndrome have been reported. Some animal experiments and a few retrospective nonrandomized studies have shown improved patency rates of anastomoses in free flaps; however, conflicting data have resulted in a lack of consensus among microsurgeons. An overall increase in systemic complications (pulmonary, cardiac, anaphylactic) has been demonstrated with dextran compared with aspirin only. Improved flap survival, leukopenia, or ischemia reperfusion protection has not been demonstrated with dextran. References: 1. Conrad MH, Adams WP. Pharmacological optimization of microsurgery in the new millennium. Plast Reconstr Surg. 2001;108:2088-2096. 2. Disa JD, Polvora VP, Pusic AL, et al. Dextran related complications in head and neck microsurgery: do the benefits outweigh the risks? A prospective randomized analysis. Plast Reconstr Surg. 2003;112:1534-1539.
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