The safety of one-per-mil tumescent infiltration into tissue that has survived ischemia.

Background: The aim of this study was to assess the safety of one-per-mil tumescent injections into viable skin flaps that had survived an ischemic insult, in order to assess the potential suitability of one-per-mil tumescent injections in future secondary reconstructive procedures such as flap revision and refinements after replantation.
Methods: Forty groin flaps harvested from 20 healthy Wistar rats weighing 220 to 270 g were subjected to acute ischemia by clamping the pedicle for 15 minutes. All flaps showing total survival on the 7th postoperative day were randomly divided into group A (one-per-mil tumescent infiltration; n=14), group B (normal saline infiltration; n=13), and group C (control, with no infiltration; n=13) before being re-elevated. Transcutaneous oxygen tension (TcPO2) was measured before and after infiltration, and changes in TcPO2 were statistically analyzed using analysis of variance, the paired t-test, and the independent t-test. The viability of flaps was also assessed using the Analyzing Digital Images software at 7 days after the second elevation.
Results: Thirty-nine flaps survived to the final assessment, with the sole exception of a flap from group A that did not survive the first elevation. TcPO2 readings showed significant decreases (P<0.05) following both one-per-mil tumescent (99.9±5.7 mmHg vs. 37.2±6.3 mmHg) and normal saline (103±8.5 mmHg vs. 48.7±5.9 mmHg) infiltration. Moreover, all groin flaps survived with no signs of tissue necrosis.
Conclusions: One-per-mil tumescent infiltration into groin flap tissue that had survived ischemia did not result in tissue necrosis, although the flaps experienced a significant decrease of cutaneous oxygenation.