Reproducibility of air plethysmography for the evaluation of arterial and venous function of the lower leg

This study assessed the test-retest reliability of air plethysmographic parameters for the evaluation of arterial and venous function of the lower extremity in normal, healthy adults. Fourteen voluntary subjects underwent air plethysmographic tests on two occasions, 1-2 weeks apart, with three tests being performed at each visit. Test-retest reliability was assessed via correlation coefficients and the intraclass correlations. Differences in the parameters of arterial inflow (AI), venous volume (VV), venous refilling time (VFT), venous refilling index (VFI), ejection volume (EV) and residual fraction (EF) obtained on the two separate occasions were small (r = 0.81 approximately 0.95; ICC = 0.94 approximately 0.99), whereas differences in ejection fraction (EF), residual volume (RV) and venous outflow (OF) measurements were much larger (r = 0.50 approximately 0.61; ICC = 0.58 approximately 0.95). The findings demonstrate that evaluation of blood flow in the lower limbs of healthy individuals using air plethysmography is reliable in test-retest measures, suggesting that this technique represents a sensitive method for quantifying changes in parameters of arterial and venous functions of the lower extremity.