Venous Occlusion Plethysmography  (VOP)

The venous occlusion plethysmography is used for the diagnosis of venous thrombosis. Therefore the veins are occluded by means of a pressure cuff so that the venous blood cannot flow out of the extremity. For this purpose a supradiastolic pressure is applied. In this case the arterial inflow is not affected because of the higher arterial blood pressure. If there is no outflow of blood, the increasing volume in the extremity corresponds with the arterial inflow.

After a defined filling of the veins is reached the cuffs are deflated and the outflow is recorded using Impedance Plethysmography (IPG). With signal analysis venous thrombosis can be detected.

Arterial Venous Occlusion Plethysmography (aVOP)

The arterial VOP can be used to diagnose arterial obliterative processes, evaluate the haemodynamic quality of collateral circulation, and to quantify parameters for comparative studies such as pharmaceutical drug effectiveness.  In contrast to VOP the cuff are inflated to a suprasystolic value. After deflation the arterial inflow is measured.