EFFECT OF EPIDURAL ANALGESIA ON VENOUS-BLOOD FLOW AFTER HIP-ARTHROPLASTY

The effects of postoperative epidural infusions using local anesthetic and narcotic were assessed in reference to lower extremity blood flow Nineteen patients who underwent unilateral total hip arthroplasty wer e randomly assigned to receive a postoperative epidural infusion of ei ther 5 mu g/ml fentanyl or 5 mu g/ml fentanyl plus 0.125% bupivacaine at a rate of 10 ml per hour, The infusions were started after complete resolution of the operative epidural blockade, Femoral venous blood f low volume and velocity were measured above and below the saphenous ve in bifurcation using an Acuson #128XP/10 computed sonography system (d uplex ultrasound) and proprietary software, Femoral venous blood flow was not affected by the type of infusion and did not increase during t he study period, However, femoral venous blood flow volume increased 5 0% after active flexion and extension of the foot, 10 times in quick s uccession, The addition of bupivacaine (a local anesthetic that blocks sympathetic afferent nerves) to a postoperative epidural infusion doe s not augment blood flow from the deep veins of the leg after total hi p arthroplasty. Alternatively, lower extremity skeletal muscle activit y significantly enhances femoral venous blood flow and may be a useful adjunct in deep venous thrombosis prevention.