Andrews B, Sommerville K, Austin S, Wilson N, Browse NL.
Effect of foot compression on the velocity and volume of blood flow in the deep
veins.
Br J Surg 1993 Feb;80(2):198-200

Department of Surgery, St. Thomas' Hospital, London, UK.

The A-V Impulse System reduces the incidence of deep vein thrombosis by
pneumatically compressing the venae comitantes of the lateral plantar artery,
causing an increase in the velocity of blood in the proximal axial veins. Using a
duplex scanner the effects of altering the pressure, pulse duration and frequency
of foot compression on the velocity and volume of blood flow in the superficial
femoral and popliteal veins were quantified. In 20 legs, foot compression of 50,
125 and 200 mmHg significantly increased the maximum venous blood flow by 9.0,
13.4 and 15.1 ml/s respectively (P < 0.001). Conversely, reducing the frequency
of compression from 6 to 3 cycles per min significantly increased the rise in
peak flow from 10.1 to 14.8 ml/s (P < 0.001). Changing the duration of
compression from 1 to 3 s had no significant effect on peak flow. Increased blood
flow is best achieved with high-pressure low-frequency foot compression.
Increasing the duration of compression beyond 1 s has no effect on augmentation
of flow in the deep veins.