Hemodynamic effect of intermittent pneumatic compression and the position of the body

The purpose of this study was to investigate the three likely mechanisms of intermittent pneumatic compression (IPC) in deep vein thrombosis prophylaxis (increased volume flow, increased flow velocity, and acceleration of flow) and to do this in a variety of positions, in different venous segments, and with the stimulus of three different compression garments.

In 12 healthy volunteers, three types of compression cuffs were used: foot, calf, and calf + thigh. The foot was compressed with 80 mm Hg, and the calf and thigh with 40 mm Hg. Duplex ultrasound scan was performed before and during the compression in the horizontal, 15-degree head-down, and 15-degree head-up positions. The common femoral, greater saphenous, profunda femoral, superficial femoral, and popliteal veins were examined.

In comparison with the horizontal position, the 15-degree head-down position was associated with an increase of volume flow and velocities and the head-up position was associated with decreased flow and velocities in the deep veins. The application of IPC caused significant increases in velocities and volume flow in all venous segments. The lowest increase in velocities and volume flow in the deep veins was observed with the subjects in the head-down position, and in the two other positions, the increases were greater and similar to each other. IPC caused a much more prominent increase in flow velocities and volume flow in deep veins compared with simple elevation of the legs.

IPC produces significant increases of venous flow volume and flow velocity and acceleration of flow. This is true whether the limbs are elevated, horizontal, or dependent. Segmental flow changes vary with the position of the patient and the compression garment used. Foot compression increases volume flow and velocity primarily in the popliteal vein. Calf compression provides maximal increases of volume flow and flow velocity through the deep veins.