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Purpose: There is currently no “ideal” monitoring technique for monitoring of both replants and flaps.  Sub-visual fluorescein and serial quantitative fluorescence have been used to assess replants and flaps concurrently with pencil Doppler, implantable Doppler, and clinical assessment on our microsurgical service since 1984.  Quantitative fluorescence has enabled us to diagnose perfusion disturbances in the face of false negative and false positive readings with pencil and implantable Dopplers.  The purpose of this study was to determine the sensitivity, specificity, and predictive value of quantitative fluorescence in microsurgery.

Test Methods and Procedures: All patients admitted to the replantation and microsurgical service from March 1, 2010 through July 30, 2010 were enrolled.   Fluorescein perfusion measurements were made every 2 hours for the first 24-48 hours following admission after microsurgical replantation or flap coverage with a skin or fasciocutaneous flap.  Clinical readings were assessed by nurses at zero, 10 minutes, and 60 minutes after injection of fluorescein.  After the first 24-48 hours, measurements were made every 4 hours and eventually tapered to every 8 hours.  Binary classification of test results was performed and sensitivity, specificity, positive and negative predictive values were calculated.

Results: A total of 4305 quantitative fluorimetry readings were performed using the Fluorostat in 33 patients.  Of the 33, 7 had microvascular transplants for limb or head and neck reconstruction.  Two had microvascular digital artery reconstruction for chronic venous ischemia from arteriosclerotic disease.  The remaining patients had mutilating hand injuries that required replantation/revascularization.  Many in this group had multiple finger replantation/revascularizations.  The Fluorostat demonstrated a sensitivity of 100%, specificity of 99% negative predictive value of 100% and positive predictive value of 86% in both arterial and venous phase testing.

Discussion: Quantitative fluorimetry is very sensitive, specific and with a 100% negative predictive value.   The Fluorostat will predict good circulation with near certainty (a rise and fall has a negative predictive value of 100%) and will flag potential cases of circulatory compromise.  Of the flagged cases, 86% had clinical evidence for circulatory compromise, while 14% did not.  The patients in whom a false monitor indication occurred did not suffer any complications, such as an unwarranted operative exploration or therapeutic maneuver.

Conclusions: The use of quantitative fluorimetry in replant and flap monitoring is highly sensitive, specific and has a 100% negative predictive value.  A negative test guarantees adequate inflow and outflow.