The influence of inflation rate on the hematologic and hemodynamic effects of intermittent pneumatic calf compression for deep vein thrombosis prophylaxis.

OBJECTIVE: The study was conducted to determine whether the different inflation rates of intermittent pneumatic compression systems used in deep vein thrombosis prophylaxis influence their hematologic and hemodynamic effects.

METHODS: A rapidly inflating intermittent calf compression system and a more gently inflating equivalent were applied to 20 healthy male volunteers for 2 hours each. Venous blood samples were taken for analysis of blood coagulation and fibrinolytic potential. Blood flow velocity was measured in the femoral vein with Doppler ultrasound.

RESULTS: Tissue factor pathway inhibitor significantly increased after the 2 hours of compression for both pumps (78.0 to 85.0 ng/mL rapid, P = .004; 76.5 to 78.0 ng/mL gentle, P = .5), as did plasminogen activator activity (0.85 to 1.05 IU/mL rapid, P = .006; 0.85 to 1.5 IU/mL gentle, P = 0.5). Plasminogen activator inhibitor 1 activity was reduced, although only approaching significance for the gentle system (16.5 to 14.3 AU/mL, P = .06). A D-dimer test for global fibrinolysis showed significant increases for the gently inflating system (97 to 411 ng/mL P < .001) but not for the rapidly inflating system (276 to 350 ng/mL P = .9). The rapidly inflating system produced significantly higher venous peak velocities and augmentations as expected.

CONCLUSIONS: Although the data confirm that both types of intermittent compression suppress procoagulant activation, rapid inflation clearly produced no extra benefit in increasing global fibrinolysis, and may be less hematologically effective.