Venous photoplethysmography: relationship between transducer position and regional distribution of venous...

This study was performed to evaluate the photoplethysmographic technique in venous disease, especially regarding the effect of different positions of the photoplethysmographic transducer and the possibility of measuring regional changes in venous circulation. For this purpose photoplethysmographic recovery times were assessed from three different parts of the lower leg, that is, anterior midcalf level, medial midcalf level, and medial malleolar level. In patients with documented venous disease, regional photoplethysmographic findings were compared with results from venous pressure measurements, ascending/descending phlebography, foot volumetry, venous plethysmography, and Doppler investigation of the anterior tibial veins. The best correlation with pressure and volume recordings at the foot was obtained at the medial malleolar level. Only photoplethysmographic recovery times recorded at the anterior aspect of the leg were influenced by reflux in the anterior tibial veins. The present results indicate that photoplethysmographic recovery times reflect regional venous hemodynamics rather than overall venous hemodynamics in the limb. Photoplethysmographic recovery times were also found to be more related to superficial than to deep venous insufficiency. The results might have clinical implications when evaluating patients with regional venous dysfunction and in follow-up studies after venous surgery.