J Reconstr Microsurg 2022; 38(08): 637-646
DOI: 10.1055/s-0042-1742733
Original Article

The 72-Hour Microcirculation Dynamics in Viable Free Flap Reconstructions

Nicholas Moellhoff
1   Division of Hand, Plastic and Aesthetic Surgery, University Hospital, LMU Munich, Munich, Germany
,
Clara Gernert
1   Division of Hand, Plastic and Aesthetic Surgery, University Hospital, LMU Munich, Munich, Germany
,
Konstantin Frank
1   Division of Hand, Plastic and Aesthetic Surgery, University Hospital, LMU Munich, Munich, Germany
,
Riccardo E. Giunta
1   Division of Hand, Plastic and Aesthetic Surgery, University Hospital, LMU Munich, Munich, Germany
,
Denis Ehrl
1   Division of Hand, Plastic and Aesthetic Surgery, University Hospital, LMU Munich, Munich, Germany
› Author Affiliations

Funding The authors have no commercial associations or financial disclosures that might pose or create a conflict of interest with the methods applied or the results presented in this article.
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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.



Publication History

Received: 18 June 2021

Accepted: 27 December 2021

Article published online:
14 February 2022

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