The Transepidermal Oxygen Flux from the Environment is in Balance with the Capillary Oxygen Supply

It has been known since the nineteenth century that oxygen is taken up by the human skin. With a newly developed sensor it became possible to examine the influence of the vascular supply on the oxygen flux into the skin, tcJ(O2). tcJ(O2) was measured optically by determining the oxygen partial pressure difference, ΔpO2 across a diffusion test membrane, which itself was brought into close contact to the skin surface. Under these conditions ΔpO2 is proportional to the tcJ(O2). The skin perfusion was varied by the application of a hyperemizing ointment on the abdomen of 12 volunteers and by suprasystolic occlusion at the thigh of 20 volunteers. The tcJ(O2) was measured at a temperature of 33°C of the humid skin. It was compared with the skin perfusion monitored by laser Doppler flow, and the capillary oxygen supply measured by transcutaneous partial pressure of oxygen, tcpO2, at an electrode temperature of 37°C. The transcutaneous O2 flux produced a distinct ΔpO2 of 81.8 ± 8.2 Torr (abdomen) and 72.8 ± 12.3 Torr (ankle). In hyperemic skin on the abdomen the O2 flux was reduced (ΔpO2 = 57.7 ± 10.6 Torr). The tcpO2 increased from 8.7 ± 10.7 to 35.1 ± 16.9 Torr. During suprasystolic occlusion, ΔpO2 increased by 6.4 ± 2.3 Torr, whereas laser Doppler flow and tcpO2 decreased significantly. These results indicate that the total oxygen supply of the epidermis and the upper dermis is guaranteed even if the perfusion varies