Blood-flow augmentation of intermittent pneumatic compression systems used for prevention of deep vein thrombosis prior to surgery.
PURPOSE: To compare, using Duplex ultrasonography, different intermittent pneumatic compression (IPC) systems to augment venous blood flow for deep venous thrombosis (DVT) prevention during and after surgery and during periods of immobility. METHODS: This cross-over study randomly assigned 26 young, healthy, adult subjects, without history of DVT, hypertension, diabetes, stroke. vascular or cardiac pathologies, to an order of knee-high, foam, single-pulse IPC device and thigh-high, vinyl, sequential-pulse pneumatic compression systems. Prior to making the flow measurement, the girth of the calf and thigh and length of the leg of each subject were determined. The right leg was used in this evaluation. RESULTS: The average flow augmentation, which is a direct measure of the amount of femoral vein blood flow velocity increase over the base, was 107%+/-49% with the knee-high system, and 77%+/-35% with the thigh-high IPC system (P<0.002). Augmentation was higher for 62% of the subjects with knee-high IPC, and for 23% of the subjects with the thigh-high system. Overall, the blood was actively moving through the vein during the decompression phase. On occasion, the velocity during the decompression phase would fall to zero for short intervals with both systems, indicating complete emptying of the vessel. Variation in limb anatomy did not significantly affect blood-flow augmentation with the knee-high IPC, but augmentation decreased with increase in girth with the thigh-high IPC. CONCLUSIONS: The study indicates that the knee-high, foam, single-pulse IPC device produces a significantly higher venous blood-flow augmentation than the thigh-high, vinyl, sequential-pulse system.