[Oxygen pressure fields in ulcers of the lower leg]

Using a multi-wire surface electrode, oxygen pressure fields were determined in leg ulcers of 11 patients with chronic venous insufficiency (cvi). In three of them, cvi was combined with arterial occlusive disease. The histograms of all patients with very low PO2 values revealed microcirculatory disturbances of the ulcer tissue. The influence of leg position is reflected in the histograms. Patients with cvi showed higher PO2 values when the leg was raised in comparison with when it was in the hanging position. The patients with mixed ulcerations showed a significant increase in tissue PO2 when the leg was in the hanging position, which shows the importance of arterial perfusion pressure. After a compression bandage had been applied to the legs with cvi, the tissue oxygen pressure of the ulcers increased markedly, probably as a result of diminished blood stasis. These results can be explained either by a rarefaction of capillaries in the ulcer tissue or by fibrin diffusion barriers around the capillaries. The changes in the histograms after bandaging are thought to be caused by an improvement in venous circulation.