ABSTRACT 
         
         Vasospasm leading to thrombosis is a major cause of free flap failure. Flap blood
            flow may improve by application of vasodilating agents to the pedicle. The purpose
            of this study is to evaluate the effect of a novel S -nitrosylating agent, O -ethyl nitrite, on flap blood flow and pedicle vessels diameter in a rat model, after
            induction of vasospasm. Two hours after surgery, the arterial diameter was significantly
            (P < .05) dilated by treatment with O -ethyl nitrite, lidocaine, or lidocaine + O -ethyl nitrite. None of these treatments had a statistically significant effect on
            blood flow or venous diameter. Twenty-four hours following surgery, both O -ethyl nitrite- and lidocaine-treated groups had larger arteries than the control
            group (P  < .05). The O -ethyl nitrite-treated animals also had significantly (P < .05) elevated blood flow
            compared with control animals, but lidocaine-treated animals did not demonstrate any
            improved flow at 24 hours. O -Ethyl nitrite may become clinically useful in microvascular surgery procedures.
         
         
         
            
KEYWORDS 
         
         
            Vasospasm - vasodilating agents - ethyl nitrite (ENO)
          
       
    
   
      
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          Michael R ZennM.D.  
            Division of Plastic, Reconstructive, Maxillofacial, and Oral Surgery 
             
            Box 3358, Duke University Medical Center, Durham, NC 27710