In an investigation on
deep venous thrombosis and
pulmonary embolism, where neither
dextran nor antithrombotic
drug prophylaxis were employed, 30 patients undergoing
total hip replacement were randomly allotted to one of two groups receiving either epidural or general anaesthesia. The epidural group (n = 15) was given 0.5%
bupivacaine with
epinephrine (5 micrograms/ml) and this was prolonged into the postoperative period for
pain relief. The general anaesthesia group (n = 15) was operated on under artificial ventilation with
nitrous oxide/
oxygen via an endotracheal tube and intravenously administered
fentanyl and
pancuronium bromide. In this group of patients
narcotic analgesics (
ketobemidone) were given intramuscularly on demand for
pain relief postoperatively. The frequency of
deep venous thrombosis involving the femoral veins, as observed at phlebography, was significantly lower in patients receiving continuous epidural block (3 of 15; 20%), than in those receiving general anaesthesia and parenteral
analgesics postoperatively (11 of 15; 73%). Further, the frequency of
pulmonary embolism, as determined by pulmonary perfusion lung scanning, was lower in patients receiving continuous epidural block (2 of 15) than in the general anaesthesia group (7 of 15). Possible explanations for these findings are discussed, including a hyperkinetic lower limb blood flow and lower fibrinolysis inhibition activity in patients given epidural block. Lower
blood transfusion requirements in patients given epidural block might also play a role, as well as a "stabilizing" effect of local anaesthetics on platelets, leukocytes and endothelial cells.