Optoelectric volume measurements to demonstrate volume changes in the lower extremities during orthostasis

Although an increase in volume of the legs during prolonged standing is a well-known phenomenon, there is little information on the initial phase in orthostasis. The aim of this study is to measure the increase in volume and its distribution in the lower extremities during orthostatic stress in healthy and varicose patients.

In this prospective study volume changes of the legs in 16 healthy individuals and 24 patients with varicose veins were investigated using an optoelectric volume measurement system (Perometer®) during 10 minutes in a standing position.

We could show that during a 10 minute standing experiment, a significant increase in volume of the entire leg, in both the healthy vein group (2.48%) and the varicose group (2.1%) occurred. Significant volume increase appeared in the upper and lower leg respectively. No significant differences could be demonstrated between right and left leg or between healthy and varicose legs.

These results in accordance with other published data indicate that changing position from lying or sitting to standing initially leads to a rapid increase in volume of the leg. These changes take place very quickly and with respect to their volume changes, are significant. The volume increase is following a bi-exponential function fitting to a fast filling compartment (venous pooling) and a slow filling compartment reflecting extravasation. Over the course of the day additional edema formation may occur.