Faster detection of ischemia in free tissue transfers by use of microdialysis

Abstract

Microdialysis is a sensitive and specific method for collection of metabolic biomarkers detecting secondary ischemia after microvascular surgery performing reconstructions by use of free tissue transfers.Microdialysis is a minimal invasive method for collection of dialysate representing the molecular composition in the tissue of interest. By using the traditional microdialysis setting with a perfusion flowrate of 0.3 μl/min, we have demonstrated a very high sensitivity and specificity clinically as well as experimentally regarding ischemia. Despite these demonstrations, there has been a hesitation to the use of microdialysis especially due to the diagnostic delay of 1–2 h.In a laboratory study and later in a porcine experiment we have demonstrated that the system can work faster by increasing the microdialysis perfusion flowrate from 0.3 μl/min to 1.0 μl/min. The median detection time for arterial ischemia in a pure muscle transfer can be reduced from 60 to 28 min. The monitoring system can be accelerated without reducing sensitivity or specificity. Furthermore, it is possible to alternate between the traditional and the new faster method without changing the ischemic alarm values.The microdialysis system is not a screening method but a final answer of whether the transfer is ischemic and the patient has to be taken back for a reoperation. The microdialysis system can be used in all sorts of free tissue transfers and by use of this faster method, the microdialysis monitoring system is approaching the demands of an ideal monitoring system for detection of ischemia in free tissue transfers.