Improved venous return by elliptical, sequential and seamless air-cell compression

The risk of deep vein thrombosis (DVT) in the peri-operative period is significant, but can be reduced with the use of mechanical intermittent pneumatic compression (IPC). These devices have reached widespread use in hospitals and have been found to be effective prophylactic measures against DVT. This study evaluates the latest design features of one particular IPC device in comparison to current models.

Duplex ultrasound scanning was performed on 40 lower extremities of 20 healthy volunteers before and during the application of the IPC device (VenaFlow System, Aircas, NJ, USA. Two hemodynamic parameters were measured, acceleration time from spontaneous baseline venous flow and peak vein velocity. All measurements were obtained by scanning proximal to the saphenofemoral junction in the common femoral vein in both extremities for each subject. Data were obtained from 3 compression cycles and averaged for each extremity. Results were compared with a recent prospective study form our center using a slow-filling and a rapid-filling sequential IPC devices.

The medians for spontaneous average peak velocities at rest of the right and left lower extremities were 26 cm/s and 24.1 cm/s. The median augmented peak velocities during the compression cycle of the device in the right and left side were 79.6 cm/s and 79.0 cm/s. This represented a 306.2% increase in average peak velocity on the right side and a 327.8% increase on the left side. The median acceleration time was 305 ms +/- 40 in the left and 310 ms +/- 50 in the right limb. There was no statistically significant difference in the spontaneous and augmented velocities between the right and left lower extremities in each subject. In comparison to existing slow- and rapid-filling IPC devices the VenaFlow System had superior peak velocities and shorter acceleration times.

The use of elliptical, sequential and rapid-filling compression of the leg with overlapping air-cells produces significant hemodynamic changes in the common femoral vein, which are superior to other sequential slow- or rapid-filling IPC devices. Randomized studies should be performed to determine the efficacy of this new device in DVT prevention.