Light reflection rheography: a simple method of assessing lower limb venous filling.

Light reflection rheography (LRR) has been developed as a simple, quick and non-invasive test of venous function which reproduces the haemodynamic parameters of venous pressure measurements by recording changes in dermal blood content of the lower limb during exercise. It uses the same principles as photoplethysmography (PPG) but is simpler to use in a clinical context. To assess the comparability of LRR, changes in ambulatory venous pressure measurements were compared to simultaneous recordings of LRR in 40 limbs of 20 individuals with venous stasis during and after a standard exercise. One hundred and twenty paired observations were made with an excellent correlation between venous refill times (VRT) recorded by the two methods (r = 0.85, P < 0.01). There was no significant correlation between exercise induced changes in venous pressure (delta P) and light reflection (delta LR) as measures of venous emptying. LRR also demonstrated differences in VRT and delta LR of the limbs of normal subjects and those with signs of venous stasis (varicose veins) (P < 0.0001). Light reflection rheography is thus a simple accurate test of venous function which may be of value in both the pre- and postoperative assessment of venous function.