The 72-Hour Microcirculation Dynamics in Viable Free Flap Reconstructions

Abstract

Background The risk for vascular complications is the highest within the first 24 hours after free flap transfer. Clinical signs of critical perfusion are often recognized with time delay, impeding flap salvage. To detect failing flaps as soon as possible and to prevent persisting microvascular impairments, knowledge of physiological perfusion dynamics in free flaps is needed. Aim of this study was to investigate the physiological perfusion dynamics of viable free flaps using the Oxygen to See (O2C) device for continuous monitoring. Methods Microcirculation was continuously monitored in 85 viable free flaps over a period of up to 72 hours following microvascular anastomosis using tissue spectrophotometry and laser Doppler flowmetry (O2C, LEA Medizintechnik, Gießen, Germany). The parameters investigated included capillary-venous blood flow (flow), oxygen saturation (SO2), and relative amount of hemoglobin (rHB). Results Microcirculatory blood flow increased significantly overall, especially within the first 18 hours after microsurgical anastomosis, after which peak formation was occurred. Mean values of SO2 showed a decreasing trend and the steepest decrease of SO2 (slope: 1.0) occurred during the steepest increase of flow between 3 and 6 hours (slope: 4.7) postanastomosis. The rHB values remained fairly constant throughout the study period. Conclusion Hyperemia after free flap transfer accounts for a significant increase of microvascular flow. Tissue oxygenation is reduced, likely due to an increase of oxygen consumption after anastomosis. A better understanding of physiological perfusion dynamics in free flaps can aid surgeons in recognizing compromised vasculature earlier and improve free flap salvage.

Influence of VAC Therapy on Perfusion and Edema of Gracilis Flaps: Prospective Case-control Study

“…This phenomenon could be explained by reactive spastic vasoconstriction in the superficial part of the flap, resulting in reduced oxygen saturations. 22 However, it should be emphasized that there were no wound healing disorders or reduced adherence of split thickness skin grafts in the VAC group. Reduced oxygen levels therefore do not seem to have much relevance in terms of clinical outcome.…”

Attached compared with unattached surface probes for monitoring flap perfusion in microvascular head and neck reconstruction: a feasibility study

“…However, this was a pilot study that evaluated the use of attached surface probes with the O2C analysis system for flap perfusion monitoring for the first time, and generally only few flaps require revision in microvascular head and neck reconstruction 1 , 4 , 23 . In addition, the short 48-h time interval for the comparison of attached and unattached surface probes in this study was based on the observation that flap monitoring is most valuable in the first 48 postoperative hours, because of the high risk of vascular comprise during this period and the low salvage rates for failing flaps beyond this period 8 , 24 – 27 .…”

Analysis of Factors Determining Patient Survival after Receiving Free-Flap Reconstruction at a Single Center—A Retrospective Cohort Study

“…In addition, data on microcirculation were gathered for both flap entities utilizing laser-doppler flowmetry and tissue-spectrometry (O2C, LEA Medizintechnik, Gießen, Germany) upon availability of the measuring device. A previously described protocol was utilized for continuous measurement of venous-capillary microvascular flow (flow), hemoglobin oxygenation (SO 2 ), and the relative amount of hemoglobin (rHb) [ 17 , 18 , 19 , 20 ]. In brief, measurements were performed continuously over a time period of 72 h post-anastomosis.…”