Effect of local application of transcutaneous carbon dioxide on survival of random-pattern skin flaps

Skin flap procedures are widely used to reconstruct skin and soft tissue defects. Skin flap necrosis is a serious postoperative complication. Many researchers have introduced pharmacological agents to improve flap ischemia in experimental studies. However, outcomes of these studies remain controversial. We previously demonstrated that transcutaneous CO₂ application improves hypoxia in fracture repair. In this study, we hypothesized that improving hypoxia by transcutaneous CO₂ application can improve the blood flow in skin flaps and increase angiogenesis. We investigated whether transcutaneous CO₂ application can increase the survival of random-pattern skin flaps.

Six-week-old male Sprague-Dawley rats were divided into two equal groups: the control group (n = 6) and CO₂ group (n = 6). A random-pattern skin flap was constructed in these rats. Topical CO₂ was applied using a hydrogel every day for 5 days in the CO₂ group. The flap survival area was measured on postoperative days 1, 3, and 5. The vessel density and expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and hypoxia-inducible factor-1α (HIF-1α) were evaluated on postoperative day 5.

A statistically significant difference was found in the percentage of the flap survival area between the two groups on postoperative days 3 and 5 (p < 0.05). Furthermore, the expression of VEGF and bFGF was significantly higher and that of HIF-1α was significantly lower in the CO₂ than in the control group (p < 0.05).

Transcutaneous CO₂ application can improve the blood flow in skin flaps and increase angiogenesis, thus increasing the survival of random-pattern skin flaps.