[The flow-volume curve. Expression of emptying as a function of venous distensibility]

Mercury strain gauge venous occlusion plethysmography is a non invasive exploration of the lower limb venous hemodynamic. Classically, venous distensibility (delta V/V %) is expressed in terms of time during venous inflow (venous occlusion) and venous outflow (after cuff deflation). The authors proposed to express the total flow Q of the limb (obtained by a differentiator of the electric signal of the strain gauge) in terms of the venous distensibility (delta V/V %) whatever recording a top each second. This new representation Q = f(delta V/V) permit a more acute visualisation of the initial part of the venous emptying: more differentiation between venous drainage and systolic arterial waves, acceleration then deceleration of the venous emptying, return of the venous wall to its initial position later than venous emptying, active venous constriction. Some parameters are proposed to described this curve and the values obtained in 50 patients without and 10 patients with deep venous thrombosis are reported.