Dodd H J, Gaylarde P M, Sarkany I
J R Soc Med. 1985 May;78(5):373-6. doi: 10.1177/014107688507800505.
Tissue anoxia has for long been invoked as a cause of venous leg ulcers, and recently it has been suggested that pericapillary fibrin prevents the diffusion of oxygen in the skin. In the present study direct measurements of skin oxygen levels on the lower leg were made using a transcutaneous oxygen monitor. In the recumbent position mean oxygen tensions were higher in patients than in controls, thus disproving the existence of any block to oxygen diffusion. In both groups there was a fall in oxygen tension to low levels on standing as a result of the normal reflex vasoconstrictor response to increased venous pressure. Exercise produced a marked rise in skin oxygen tension in normal legs but not in those affected by venous insufficiency. In normal subjects exercise reduces venous pressure, thus removing the stimulus for reflex vasoconstriction. In patients with defective valves, the venous pressure remains high during exercise and reflex vasoconstriction persists. It is concluded from this study that the sustained low skin oxygen tension in the upright position even during exercise is responsible for leg ulcer formation associated with venous insufficiency. Normal legs are protected by a rise in skin oxygenation during exercise.
长期以来，组织缺氧一直被认为是导致下肢静脉溃疡的一个原因，最近有人提出，毛细血管周围的纤维蛋白会阻碍氧气在皮肤中的扩散。在本研究中，使用经皮氧监测仪对小腿皮肤的氧水平进行了直接测量。在卧位时，患者的平均氧分压高于对照组，从而反驳了存在任何氧气扩散障碍的观点。由于对静脉压升高的正常反射性血管收缩反应，两组站立时氧分压都会降至低水平。运动使正常腿部的皮肤氧分压显著升高，但静脉功能不全的腿部则不然。在正常受试者中，运动可降低静脉压，从而消除反射性血管收缩的刺激。在瓣膜功能不全的患者中，运动期间静脉压仍然很高，反射性血管收缩持续存在。从这项研究可以得出结论，即使在运动期间，直立位时持续的低皮肤氧分压是导致与静脉功能不全相关的腿部溃疡形成的原因。正常的腿部通过运动时皮肤氧合增加而得到保护。
