Oxygen diffusion in chronic venous ulceration.

A diffusion barrier to oxygen caused by fibrin deposition around dilated, proliferating capillaries in patients with venous hypertension may contribute to the development of venous ulceration. This diffusion barrier was studied in 18 patients with venous ulcers using the transcutaneous oxygen (TcPO2) monitor (TCM204 Radiometer, America). TcPO2 sensors were placed adjacent to venous ulcers on lower limbs and on the chest and foot of each patient. Readings were taken after a sensor temperature of 44 degrees C was reached (10-15 minutes). TcPO2 values were markedly decreased in skin adjacent to the ulcers (10 +/- 2 mmHg) compared with those of the chest (64 +/- 2 mmHg) and foot (43 +/- 2 mmHg). Inhalation of 100% oxygen for 10 minutes increased chest TcPO2 in all patients (145 +/- 8 mmHg) and increased TcPO2 in skin around the ulcers in 17 of 18 patients (61 +/- 13 mmHg). This study supports the existence of a local pathologic barrier to oxygen diffusion in patients with venous ulcers.