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CC BY 4.0 · J Reconstr Microsurg Open 2025; 10(01): e6-e11
DOI: 10.1055/a-2576-0650
Original Article

Blood Gaseous Changes in Patients Undergoing a Dangling Protocol after Lower Leg Free Flap Reconstruction

Mike Westmeijer
1   Department of Plastic and Reconstructive Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
,
Emile B. List
1   Department of Plastic and Reconstructive Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
,
Wiesje Maarse
1   Department of Plastic and Reconstructive Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
,
J. Henk Coert
1   Department of Plastic and Reconstructive Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
,
David D. Krijgh
1   Department of Plastic and Reconstructive Surgery, University Medical Center Utrecht, Utrecht, The Netherlands
› Author Affiliations Funding None.
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Abstract

Background

Patients undergoing free flap reconstruction of the lower extremity are typically started on a postoperative dangling protocol. This protocol gradually exposes the free flap to increasing gravitational forces. This study aimed to quantify the internal blood gaseous changes within the free flap over the course of a dangling protocol.

Methods

Three patients who underwent lower leg free flap reconstruction were included. Capillary blood gas samples were taken daily for six consecutive days (postoperative days 7–12) from the free flap before and after dangling, as well as from the contralateral, “healthy” leg. Mean blood gas curves were created for partial pressure of oxygen (pO2), partial pressure of carbon dioxide (pCO2), and potential hydrogen (pH) levels. A paired t-test was used to compare mean blood gas values.

Results

Baseline mean pO2 was decreased (p = 0.002), pCO2 was increased (p < 0.001), and pH levels were lowered (p = 0.021) at the site of the free flap, compared with the contralateral, “healthy” leg. Mean pre- and post-dangling pO2 levels were not significantly different (p = 0.380). Mean pCO2 levels significantly increased after dangling (p = 0.028). Over the course of the dangling protocol, mean pO2, pCO2, and pH curves remained considerably stable.

Conclusion

Blood samples taken from the free flap show that the mean pO2 and pH levels are lower, and pCO2 levels are higher compared with the contralateral, “healthy” leg. Furthermore, an increase in dangling duration does not cause significant changes in blood gas values. This raises the question of whether the current form of the dangling protocol accomplishes its intended goal of gradually challenging the flap.

Keywords

reconstruction - free flap - dangling - lower leg - blood gas

Previous Presentation

This research is original. An abstract was presented at the European Plastic Surgery Research Council in August 2024 (Brno, Czech).


Ethical Approval

The study was approved by the local institutional review board (Medisch Ethische Toetsings Commissie [METC], protocol no.: 17/920). All patients provided written informed consent before POD 5. Throughout the study, patients had the opportunity to withdraw at any given time.


Supplementary Material



Publication History

Received: 14 January 2025

Accepted: 20 March 2025

Accepted Manuscript online:
07 April 2025

Article published online:
28 April 2025

© 2025. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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