Skin grafts and compromised skin flaps represent a classical problem involving insufficient oxygen supply to tissue.
Plastic surgeons use grafts and flaps to repair serious tissue damage and to close or cover wounds. Skin is taken from one part of the patient’s body and used to cover a break in the skin on another part. There are several types of skin grafts. They include full-thickness grafts in which all of the skin layers are used, and split-thickness grafts in which only the top layers and several of the deeper layers are used. There are also pedicle grafts, in which part of the skin remains attached to the donor site. This allows the old blood supply to remain intact while a new blood supply develops.
A freshly applied split-thickness graft receives no oxygen until tiny blood vessels called capillaries can penetrate it. Such capillary ingrowth normally takes place over a two to three day period. If this does not happen, it’s unlikely that the graft will survive. HBOT improves the chances that a graft will take, both by supplying oxygen and by encouraging quick capillary growth.
Providing hyperoxygenation increases the oxygen tension in the graft bed and wound margins up to 1500 percent. It also causes a marked increase in the amount of oxygen that reaches the graft through the compromised blood vessels. The volume of tissue that derives sufficient oxygen from a single damaged blood vessel increases 16 fold, and marked tissue salvage results.
Lack of oxygen tends to be less of a problem with full-thickness and pedicle grafts since these grafts have their own supply of capillaries. Even so, it still takes time for good blood flow to become established through these type of grafts, Therefore, full-thickness and pedicle grafts also respond to HBOT. In many instances HBOT is used only after a skin graft starts to fail.
- While HBOT can help save failing grafts it can be even more effective when used before surgery to keep grafts from failing in the first place.
- HBOT also offers strategies for reducing edema. The edema reduction effect, induced by the relative spasm of a precapillary arteriolar sphincter helps to limit the swelling of the graft or flap. The high oxygen tension achievable with HBOT induces neovascularization. Among other things, oxygen dissolved in plasma is readily available to tissues and organs thus limiting damage from reperfusion injury.
- HBOT’s effectiveness in aiding skin graft survival is supported by research. The effectiveness of HBOT is shown in grafting and in reimplantation of limbs, with a salvage rate of 75% for the HBOT group compared to 46% for the controls, with 100% HBOT salvage when the patient is treated within 72 hours post-operatively.
- The use of HBOT for the preparation of a base for skin grafting and the preservation of compromised skin grafts has been well documented as effective.