Increasing circulation in the lower limb under general anesthesia using the A-V impulse system.

The action of foot impulse technology (FIT) in reducing the risk of deep vein thrombosis (DVT) is well established. We hypothesized that intraoperative use of FIT devices will be effective in the prophylaxis of DVT. The aim of this study was to investigate the effect of a FIT device (A-V impulse system) on the venous flow of the lower extremity using duplex ultrasound scanning while the patient was under general anesthesia. Thirteen surgical patients who had no lower limb vessel lesions were selected for the study. Duplex scanning was used to measure blood velocity in the right common femoral vein, with and without the foot pump, before and during general anesthesia. The mean resting velocity was 33.2 +/- 5.5 cm/sec in the pre-anesthetic state, 32.1 +/- 4.2 cm/sec under anesthetic, and 30.4 +/- 5.0 cm/sec postoperatively. The peak velocities with the pump active were 38.6 +/- 5.0 cm/sec before anesthetic, 54.6 +/- 5.9 cm/sec while anesthetized, and 52.7 +/- 7.8 cm/sec postoperatively. The measured increases while under anesthesia and postoperatively both reached statistical significance (p<0.05). Our study demonstrated that use of the A-V impulse system causes a statistically significant increase in venous velocity of the lower extremity while the patient is under general anesthesia.