Use of lightguide spectrophotometry to investigate the effect of postural changes on skin oxygenation in deep venous insufficiency.

Background: Postural changes play an important role in the development of venous disease. The aim of this study was to investigate skin oxygenation in patients with deep venous insufficiency.

Methods: Haemoglobin oxygen saturation (SO2) was measured with macro- and micro-lightguide spectrophotometry in clinically normal skin at the gaiter area with the leg in the supine position, raised to 45 degrees and on standing. Similarly, transcutaneous oxygen tension (PtcO2) and laser Dopper flux (LDF) values were obtained. SO2 was also measured after heating the skin to 44 degrees C in the supine and standing positions.

Results: SO2 and PtcO2 decreased on leg raising (P < 0.05 and P < 0.01 respectively). SO2 fell on standing (P < 0.05) while PtcO2 rose (P < 0.05). On heating the skin, SO2 increased (P < 0.05) on standing. LDF fell on standing (P < 0.005) but increased on leg raising (P < 0.05).

Conclusion: Lightguide spectrophotometry showed a profound decrease in skin oxygenation on standing and leg raising; PtcO2 measurements may miss the role of vasoconstriction with postural changes.