Randomized Trial of Sequential Compression Versus Ankle-Calf Movement to Increase Femoral Venous Velocity

Objective In postoperative patients with a high risk of bleeding, sequential compression devices (SCD) and ambulation are effective methods to reduce venous thromboembolic (VTE) risks. High leg venous flow decreases VTE risk. We postulated that ankle flexion and extension (AFE) while in bed increased leg venous flow velocity as well. We wished to compare the effectiveness of SCD versus AFE in increasing leg venous velocity. Methods Thirty-two healthy volunteers were recruited into the study. Each subject had two legs that were randomized into SCD or AFE. After 15 minutes of rest, SCD or AFE was applied, followed by 15 minutes of rest, and then an alternate treatment was given to the second leg. The sequence of leg and methodology was then reversed so the second treatment was applied to the first leg, and the first treatment to the second leg, and measurements were obtained. All treatments were separated by a rest period of 15 minutes. The venous velocity on each leg was measured by Doppler ultrasound at the superficial femoral vein. Venous velocity was measured initially (first cycle peak venous velocity) and during subsequent cycles. The alternate treatments on both legs with both treatments allowed for analysis in a manner where each subject could act as its control. Results Relative to baseline bed rest, SCD increased peak venous flow velocity by 112%, while AFE increased peak venous flow velocity by 161%. AFE resulted in 43% higher venous velocity on average than did SCDs (p<0.05). Conclusions AFE leads to significantly higher venous flow in the femoral veins of healthy subjects.