The Effect of Elastic Compression on Tcpo 2 in Limbs with Venous Stasis

Abstract

A low oxygen tension might contribute to the dermatological changes produced by deep venous insufficiency and venous stasis. Since elastic support is often prescribed for stasis disorders, it would be of value to know whether compression alters the oxygen tension in affected skin. We performed studies in which the transcutaneous Po₂ (TcPo₂) was determined for the foot or lower leg in subjects with normal veins (n = 9) or with dermatitis caused by documented deep venous insufficiency (n = 14). Measurements were made using O₂-sensing electrodes placed 1–2 cm apart; surface temperature was 45°C for one electrode (producing maximal vasodilation of the underlying skin) and 42°C for the other (producing submaximal vasodilation). The vasodilation index (VI = TcPo₂ at 42 °C/TcPo₂ at 45°C) was used as an index of vasomotor tone. In normal limbs, TcPo₂ (mmHg) and VI were affected by the subject's posture (TcPo₂ = 38.8 at 42°C and 61.4 at 45°C when supine; 40.8 at 42°C and 74.6 at 45°C when upright with legs dependent; VI = 0.63 supine and 0.53 upright). In limbs with venous stasis, TcPo₂ and VI were considerably lower (TcPo₂ = 23.6 at 42°C and 51.5 at 45°C when supine; 20.8 at 42°C and 60.5 at 45°C when upright; VI = 0.48 supine and 0.37 upright). Following the application of an elastic wrap to the limbs with stasis, upright values for TcPo₂ and VI were substantially improved (TcPo₂ with compression = 28.8 at 42°C and 62.4 at 45°C; VI = 0.46). We conclude that (1) TcPo₂ is reduced in regions of skin affected by stasis dermatitis, and (2) elastic compression improves TcPo₂ (during upright posture) in limbs with stasis dermatitis.