Capillary blood flow and cutaneous uptake of oxygen from the atmosphere

摘要

In 1987 Baumgaertl, using needle electrodes to measure pO_2 in skin, demonstrated that a minimum pO_2 value could be observed between the surface and the capillary bed. This indicated that there is an O_2 flux through the epidermis supplying the upper layers of the skin. The recent development of a fluorescence-based O_2-fluxoptode for measuring oxygen flux has meant that the phenomenon could be studied directly. More recently Stiicker et. al. showed, using simultaneous measurement of oxygen flux, transcutaneous pO_2 and laser Doppler perfusion, that the epidermal oxygen uptake from the atmosphere is in balance with the blood-borne (haematogenic) oxygen supply. These measurements of oxygen flux and previous measurements of pO_2 profiles indicated that capillary blood flow in skin at normal skin temperature may not contribute to the oxygen supply of the superficial layers. In order to investigate this further, in the present study the transcutaneous hydrogen clearance technique was applied at various skin temperatures between 33℃ and 40℃. Laser Doppler flowmetry (LDF), transcutaneous oxygen flux, and transcutaneous oxygen measurements were also carried at the same site. The inability to detect hydrogen at the skin surface at 33℃ confirms the minimal contribution of capillary blood flow to the oxygen supply to superficial layers.