The transepidermal oxygen flux from the environment is in balance with thecapillary oxygen supply

It has been known since the nineteenth century that oxygen is taken up by t he 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( O-2). tcJ(O-2) was measured optically by determining the oxygen partial pre ssure difference, Delta pO(2) across a diffusion test membrane, which itsel f was brought into close contact to the skin surface. Under these condition s Delta pO(2) is proportional to the tcJ(O-2). The skin perfusion was varie d by the application of a hyperemizing ointment on the abdomen of 12 volunt eers and by suprasystolic occlusion at the thigh of 20 volunteers. The tcJ( O-2) was measured at a temperature of 33 degrees C of the humid skin. It wa s compared with the skin perfusion monitored by laser Doppler flow, and the capillary oxygen supply measured by transcutaneous partial pressure of oxy gen, tcpO(2), at an electrode temperature of 37 degrees C. The transcutaneo us O-2 flux produced a distinct Delta pO(2) of 81.8 +/- 8.2 Torr (abdomen) and 72.8 +/- 12.3 Torr (ankle). In hyperemic skin on the abdomen the O-2 fl ux was reduced (Delta pO(2) = 57.7 +/- 10.6 Torr). The tcpO(2) increased fr om 8.7 +/- 10.7 to 35.1 +/- 16.9 Torr. During suprasystolic occlusion, Delt a pO(2) increased by 6.4 +/- 2.3 Torr, whereas laser Doppler flow and tcpO( 2) decreased significantly. These results indicate that the total oxygen su pply of the epidermis and the upper dermis is guaranteed even if the perfus ion varies.