Oxygen tension and consumption measured by a tc‐Po 2 electrode on heated skin before and after epidermal stripping

Oxygen tensions, cutaneous blood flow rate, and skin oxygen consumption rate were detrrmincd by tc‐Po 2 measurements at an electrode temperature of 45°C. The epidermal surface was stripped by 50 applications of adhesive plaster to the surface. Ten healthy, normotensive adults were examined. Cutaneous blood flow rate was 41.2 ± 8.6 ml. (100 g) ‐1 . min ‐1 before and 42.8 ± 5.9 ml. (100g) ‐1 . min ‐1 after epidermal stripping. Oxygen consumption before stripping was 0.327 ± 0.065 ml O 2 · (100 g) ‐1 · min ‐1 , and after stripping it was determined at two different saturation levels to be 0.208±0.072 ml O 2 · (100 g) ‐1 · mill ‐1 and 0.251 ± 0.096 ml O 2 · (100g) ‐1 . min ‐1 · Capillary temperature was estimated to be approximately 43°C before and after stripping. At this temperature mean arterial Po 2 was estimated to be 18.1 kPa (136 mmHg), which would be reduced by the computed local metabolism to a mean capillary Po 2 of 14.4 kPa (108 mmHg) before stripping and 15.2 kPa (114 mmHg) after. Stripping increased mean skin Pop from 10.9 ± 0.6 kPa (82.3 ± 4.7 mmHg) to 14.6 k 1.0 kPa (109.4 ± 7.7 mmHg). Thus, stripping eliminated 82% of the gradient between the capillaries and electrode while reducing the computed oxygen consumption by 23–36%. It is concluded that the epidermal membrane is a significant barrier to oxygen diffusion and that the transcutaneous oxygtm electrode has a significant effect on skin Po 2 owing to its own even low oxygen consumption. This will reduce the observed skin Pop significantly.