Hyperbaric oxygen has a specific indication for diabetic wounds, and knowing it explains the timing of a referral better than anything else.
A specific indication for hyperbaric oxygen therapy in wound healing is a Wagner grade 3 diabetic wound that hasn’t responded to at least 30 days of conventional therapy.
That’s two conditions in one sentence. The first is the grade. The Wagner scale grades how severe a diabetic foot wound is: grade 0 is intact skin, grade 1 a superficial wound, grade 2 a wound reaching bone or tendon, grade 3 an abscess, osteomyelitis or tendonitis, grade 4 gangrene involving the forefoot or toes, and grade 5 gangrene involving the whole foot. Grade 3 is the one named.
The second is at least 30 days of conventional therapy without a response. That’s why a referral comes when it does rather than at the start. The indication describes a wound that has already been treated conventionally for a month without responding.
Why oxygen at all? Because of what these wounds are. Diabetic wounds that won’t heal are often chronically or acutely infected and have a poor blood supply. This is usually in the small arteries farther out in the limb, though larger arteries can be involved, sometimes with venous congestion, neuropathy and swelling as well. The principle is simple: oxygen is important for healing, and the chamber pressure helps your blood carry more oxygen to organs and tissues.
Hyperbaric oxygen therapy is also one of the methods used to help remove dead or infected tissue in a diabetic foot ulcer, because it helps deliver more oxygen to the wound.
A referral is not a verdict on the wound, and it isn’t a last resort in the way people often assume. It’s a treatment with a defined indication, and that indication is met when a wound of a particular grade hasn’t responded to a month of conventional care.