The effect of compression on venous haemodynamics assessed by quantitativephotoplethysmography

Background: The purpose of this study was to examine quantitatively the eff ect of compression stockings on venous haemodynamics at the level of the an kle. Methods: To obtain quantifiable results, a computer-controlled photoplethys mographic system was used to measure the displacement of local blood volume induced by exercise (exercise displacement volume, EDV) and by tilting the subject (tilt displacement volume, TDV). The test was repeated after appli cation of class I compression stockings 20-30 mmHg). The ratio EDV/TDV is c onsidered to represent the efficiency of the veno-muscular pump. Three grou ps of subjects were studied: a control group (n = 8), patients with telangi ectases (n = 10) and a group with large varices (n = 11). Results: The application of external compression had a quantifiable and ben eficial effect on venous haemodynamics and was most significantly documente d by an increase in veno-muscular efficiency (EDV/TDV) from 28% to 44% in t he varicose vein patients. Statistically significant increases of EDV/TDV c ould also be identified in the telangiectatic patients and normal subjects. EDV also showed an increase with compression stockings: however, statistic al significance was only reached in the varicose vein group. Conclusion: External compression (class 1 compression stockings! significan tly improved venous haemodynamic indices, especially in patients with varic ose veins. Quantitative photoplethysmography used in this study permits a f ast, non-invasive and quantifiable evaluation of venous haemodynamics of th e lower extremities.